final presentation

NEFT DASHLARI GCSIINEFT DASHLARI GCSII

TRAINING ON NEW GAS STATION CONTROL SYSTEMS, TRAINING ON NEW GAS STATION CONTROL SYSTEMS, INSTRUMENTATION AND DETECTION SYSTEMS INSTRUMENTATION AND DETECTION SYSTEMS

PRESENTATIONPRESENTATION

SPEACHER: Mandarini SalvatoreSPEACHER: Mandarini Salvatore

COMPANY: RENCO COMPANY: RENCO

visit our web site. visit our web site. www.renco.itwww.renco.it

ACRONYMSACRONYMS DCS: Distribute Control System;DCS: Distribute Control System;

ESD: Emergency Shut Down;ESD: Emergency Shut Down;

SDV: Shut Down Valve;SDV: Shut Down Valve;

BDV: Blow Down Valve;BDV: Blow Down Valve;

MAIN PROCESS DATAMAIN PROCESS DATA Gas Flow: 3.6 MM Scm/day:Gas Flow: 3.6 MM Scm/day:

Pressure: Pressure:

Inlet: 4,5-6 bara;Inlet: 4,5-6 bara; Outlet: 35-58 bara.Outlet: 35-58 bara.

Temperature: Temperature:

Inlet: 5-25 °C; Inlet: 5-25 °C; Outlet: Outlet: ~~45°C.45°C.

Water content.Water content.

Inlet: 0,4 g/Scm;Inlet: 0,4 g/Scm; Outlet: Water dew point -5°C @ 58 bar.Outlet: Water dew point -5°C @ 58 bar.

DCS SUB -SYSTEMSDCS SUB -SYSTEMS The compressor station is divided is Subsystems:The compressor station is divided is Subsystems:

Sub-system Main HeadersSub-system Main Headers

Sub-system HP Fuel Gas HeaderSub-system HP Fuel Gas Header

Sub-systems Fuel Gas HP, LPSub-systems Fuel Gas HP, LP

Sub-system Seal Gas HP, LPSub-system Seal Gas HP, LP

Sub-system Turbines HP. LPSub-system Turbines HP. LP

Sub-system Glycol Regeneration SystemSub-system Glycol Regeneration System

Sub-system Glycol Regeneration Utility SystemSub-system Glycol Regeneration Utility System

DCS SYSTEMDCS SYSTEM

The Compressor Station can be controlled in the Following Way:The Compressor Station can be controlled in the Following Way:

Semiautomatic; (Professional User) Semiautomatic; (Professional User)

Automatic; (Basic User)Automatic; (Basic User)

Manual; (Professional User)Manual; (Professional User)

In semi automatic operating mode the operator can leads the single sub system status in a defined state.In semi automatic operating mode the operator can leads the single sub system status in a defined state.

Each “Sub-system” is controlled by “ PROCEDURE”. Each “Sub-system” is controlled by “ PROCEDURE”. In Semiautomatic operating mode Static and Dynamic In Semiautomatic operating mode Static and Dynamic procedure of sub procedure of sub

systems involved are executed by DCS Control system. systems involved are executed by DCS Control system.

The sub system dynamic states represent transitions between two static states of the same sub system.

During the execution of Dynamic Procedure commands and check up are carried out sequentially by DCS During the execution of Dynamic Procedure commands and check up are carried out sequentially by DCS Control system. Control system.

During the execution of Static Procedure conditions are continuously checked up by DCS Control system. During the execution of Static Procedure conditions are continuously checked up by DCS Control system.

Closing and Opening valves commands are not enabled on valves faceplate if the relative subsystem is in Closing and Opening valves commands are not enabled on valves faceplate if the relative subsystem is in Semi automatic Semi automatic

operating mode and only the “CASCATE” valves operating mode on faceplate is active. operating mode and only the “CASCATE” valves operating mode on faceplate is active.

SEMIAUTOMATIC: (PROFESSIONAL USER)SEMIAUTOMATIC: (PROFESSIONAL USER)

TRANSITION RULES BETWEEN STATESTRANSITION RULES BETWEEN STATES

The gas compression plant is decomposed in several sub-systems

and at any sub systems is associated a state variable that

defines the current condition.

DCS has to check the operator request to switch from a DCS has to check the operator request to switch from a state state

to another.to another.

Not all states are reachable starting from a generic Not all states are reachable starting from a generic state.state.

At the beginning of each procedure in order to allow the At the beginning of each procedure in order to allow the requested transition the actual state check up shall be requested transition the actual state check up shall be

carried carried out.out.

At the end of each procedure the system will provide to At the end of each procedure the system will provide to update update

the value of state variable of process sub system. the value of state variable of process sub system.

The process sub-systems can be in Unknown state:The process sub-systems can be in Unknown state:

• UNKNOWN: Dynamic state generated by a UNKNOWN: Dynamic state generated by a TIMEOUT or an ERROR.TIMEOUT or an ERROR.

Following are showed the possible transitions:Following are showed the possible transitions:

• UNKNOWN state is reachable starting from UNKNOWN state is reachable starting from each each

state in presence of TIMEOUT/ERRORS.state in presence of TIMEOUT/ERRORS.

At the end of each procedure the system will provide to At the end of each procedure the system will provide to update the value of state variable of process sub-system.update the value of state variable of process sub-system.

When the sub-system state is UNKNOWN all the alarms When the sub-system state is UNKNOWN all the alarms are are

armed.armed.

Hysteresis is necessary to avoid continuous Hysteresis is necessary to avoid continuous changeover. changeover.

ABORT: In case of abnormal exit from an automatic procedure (abort) the state variable ABORT: In case of abnormal exit from an automatic procedure (abort) the state variable

shall be set to shall be set to the previous static status (the value of the state variable had at the beginning of the the previous static status (the value of the state variable had at the beginning of the

dynamic procedure dynamic procedure itself)itself)

ERROR: In case of a malfunction of the system response is detected, an error state is ERROR: In case of a malfunction of the system response is detected, an error state is generated.generated.

ALARM ONLY: The signals that generate this effect, does not affect the proceeding of the ALARM ONLY: The signals that generate this effect, does not affect the proceeding of the sequence.sequence.

CALL: Sequence Jump to another CALL: Sequence Jump to another dynamic proceduredynamic procedure of the same sub-system. of the same sub-system.

KEYWORDSKEYWORDS

When a step of dynamic transition can't finish within a determinate time interval (TIMEOUT), When a step of dynamic transition can't finish within a determinate time interval (TIMEOUT), or an or an

ERROR occurred, DCS produces an interrupt with indications of the cause and gives choice to ERROR occurred, DCS produces an interrupt with indications of the cause and gives choice to the operator the operator

to change the status to UNKNOWN or to force the process system in SAFETY CONDITION. to change the status to UNKNOWN or to force the process system in SAFETY CONDITION.

The Safety Condition The Safety Condition of process sub-system is the final condition of the automatic of process sub-system is the final condition of the automatic safety procedures.safety procedures.

When the state is UNKNOWN or the control mode is MANUAL, the DCS tries continuously to When the state is UNKNOWN or the control mode is MANUAL, the DCS tries continuously to recognize recognize

the new status (one of the defined static states). the new status (one of the defined static states).

If this is possible the UNKNOWN status changes to the recognized one.If this is possible the UNKNOWN status changes to the recognized one.

Operator can understand what forbid the status recognition looking at Status Table.Operator can understand what forbid the status recognition looking at Status Table.

Status Table is a graphic page where, for each automatic procedure and for each relevant Status Table is a graphic page where, for each automatic procedure and for each relevant static status, static status,

are listed the involved conditions with a back color associated: red when the condition is are listed the involved conditions with a back color associated: red when the condition is unsatisfied, greenunsatisfied, green

otherwise. otherwise.

TIME OUT/ERRORTIME OUT/ERROR

State Recognized ProcedureState Recognized Procedure In normal plant working conditions (automatic or Semi automatic operation mode), SRP is

disabled for process sub-plant that are on dynamic state and activated for process sub-plant that are in static state.

For last cases, SRP checks the setting of the process sub-plant and in case the state doesn’t recognized,

the state variable is set to UNKNOWN.

The “known state” lost may be caused by an operator manual interventions and/or ESD interventions and/or

faults and/or loosing of signals that identify a static state (Static state not recognized)

ESD interrupt, are “unforeseen events”.

Dynamic procedures in Semi automatic mode will be available again only for those process sub-plant which

have the state variable different to UNKNOWN;

An exception at this rule is for the dynamic procedures which bring the process sub-plant in safety condition

(DEPRESSURIZATION, STOPPING, COLD CATCH).

These dynamic procedure in Semi automatic mode must be reacheble from any state and must be execute in

any case, independently from process sub-system state (unconditional procedures).

State Recognized MatrixState Recognized Matrix

State Recognized Matrix shows, for any process sub-plant, all possible Static States in relationship with main items.

Any row contains, then, necessary and sufficient conditions in order that a specific state may be recognized.

In case that a condition is insignificant for state recognized, this will be marked with “ / “.

The SRP, starting from the first row, has to execute all the check list in the column and compare the result with the relative value;

In case the check of ALL conditions is true the state associated to the row is set like current sub-plant state.

In case the check is false, next row will be examined.

If any state is recognized, at the end of the loop, state variable of process sub-plant will be set as UNKNOWN.

VENT MONITORINGVENT MONITORING

If manual mode is requested by operator when process sub-system is in pressurized state, it If manual mode is requested by operator when process sub-system is in pressurized state, it is possible that a vent line is opened is possible that a vent line is opened by operatorby operator for some time and the pressure falls near for some time and the pressure falls near atmospheric value. atmospheric value.

If, after that, the operator closes the vent valve and pressurizes the sub-system again If, after that, the operator closes the vent valve and pressurizes the sub-system again without purging it, the process fluid may be contaminated.without purging it, the process fluid may be contaminated.

When the auto mode will be selected again the control system has no information about this When the auto mode will be selected again the control system has no information about this circumstance. circumstance.

To avoid this shall be define a new variable/flag VENT_MONITORING used for monitoring the To avoid this shall be define a new variable/flag VENT_MONITORING used for monitoring the situation described. situation described.

This variable is SET during the PRESSURIZATION and RESET if the pressure fall bellow a This variable is SET during the PRESSURIZATION and RESET if the pressure fall bellow a minimum value.minimum value.

However it shall be possible for the operator to force VENT_MONITORING STATUS by a However it shall be possible for the operator to force VENT_MONITORING STATUS by a dedicated push button in manual mode.dedicated push button in manual mode.

The “VENT MONITORING” procedure is "always running". The “VENT MONITORING” procedure is "always running".

It means these procedures run in parallel mode to all the other ones foreseen for this plant It means these procedures run in parallel mode to all the other ones foreseen for this plant sub-system, even when manual mode is selected.sub-system, even when manual mode is selected.

Obviously automatic procedures are written so that no mismatch can happen with the always Obviously automatic procedures are written so that no mismatch can happen with the always running procedures. running procedures.

ALWAYS RUNNING PROCEDURESALWAYS RUNNING PROCEDURES

EMERGENCYEMERGENCY

During normal operation the DCS takes the control of SDV/BDV valves and all During normal operation the DCS takes the control of SDV/BDV valves and all equipments.equipments.

When a cause of Emergency shutdown is activated the ESD system take the control of When a cause of Emergency shutdown is activated the ESD system take the control of some shutdown/ blow down valves and equipment. some shutdown/ blow down valves and equipment.

When the ESD action is terminated the DCS tries to recognize the new status (one of the When the ESD action is terminated the DCS tries to recognize the new status (one of the defined static states). defined static states).

If this is possible the UNKNOWN status changes to the recognized one, otherwise an alert If this is possible the UNKNOWN status changes to the recognized one, otherwise an alert message is sent to operator.message is sent to operator.

HP FUEL GAS HEADER SUB-SYSTEMHP FUEL GAS HEADER SUB-SYSTEM The process sub-system can be in Depressurization state:The process sub-system can be in Depressurization state:

• DEPRESSURIZATION: Dynamic state which allows to vent process fluid. DEPRESSURIZATION: Dynamic state which allows to vent process fluid.

Following are showed the possible transitions:Following are showed the possible transitions:• DEPRESSURIZATION dynamic state allows the transition from any state to DEPRESSURIZED.DEPRESSURIZATION dynamic state allows the transition from any state to DEPRESSURIZED.

In order to update the SUB SYSTEM status to DEPRESSURIZED status during the execution of In order to update the SUB SYSTEM status to DEPRESSURIZED status during the execution of DEPRESSURIZATION procedure essentially the following conditions and actions shall be verified and followed DEPRESSURIZATION procedure essentially the following conditions and actions shall be verified and followed through:through:

1.1. Turbine LP A,B – HP A,B Seal Gas sub systems shall be isolated and inlet valves “SDV – 3X50“ Turbine LP A,B – HP A,B Seal Gas sub systems shall be isolated and inlet valves “SDV – 3X50“ shall be closed..shall be closed..

2.2. HP Fuel Gas sub system inlet valve “SDV – 3140“ shall be closed.HP Fuel Gas sub system inlet valve “SDV – 3140“ shall be closed.3.3. HP Fuel Gas sub system vent valve “BDV – 3139“ shall be open.HP Fuel Gas sub system vent valve “BDV – 3139“ shall be open.4.4. TIMEOUT shall be expired.TIMEOUT shall be expired.

HP FUEL GAS HEADER SUB-SYSTEMHP FUEL GAS HEADER SUB-SYSTEM The process sub-system can be in Depressurized state:The process sub-system can be in Depressurized state:

• DEPRESSURIZED: Static state with inlet HP fuel valve closed and vent line open.DEPRESSURIZED: Static state with inlet HP fuel valve closed and vent line open.

Following are showed the possible transitions:Following are showed the possible transitions:• DEPRESSURIZED state can be achieved by completing the procedure of DEPRESSURIZED state can be achieved by completing the procedure of

DEPRESSURIZATION.DEPRESSURIZATION.

SAFETY CONDITION of process sub-system, that represents the final condition of automatic SAFETY CONDITION of process sub-system, that represents the final condition of automatic protection protection

procedures, coincides with DEPRESSURIZED state.procedures, coincides with DEPRESSURIZED state.

In order to maintain the DEPRESSURIZED SUB SYSTEM status essentially the following conditions In order to maintain the DEPRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified :shall be verified :

1.1. HP Fuel Gas sub system inlet valve “SDV – 3140“ shall be closed.HP Fuel Gas sub system inlet valve “SDV – 3140“ shall be closed.2.2. HP Fuel Gas sub system vent valve “BDV – 3139“ shall be open.HP Fuel Gas sub system vent valve “BDV – 3139“ shall be open.

HP FUEL GAS HEADER SUB-SYSTEMHP FUEL GAS HEADER SUB-SYSTEM The process sub-system can be in Pressurization state:The process sub-system can be in Pressurization state:

• PRESSURIZATION: Dynamic state which allows the purging of trapped air and the PRESSURIZATION: Dynamic state which allows the purging of trapped air and the pressurization of process sub-system.pressurization of process sub-system.

Following are showed the possible transitions:Following are showed the possible transitions:• PRESSURIZATION dynamic state allows the transition from DEPRESSURIZED to PRESSURIZATION dynamic state allows the transition from DEPRESSURIZED to

PRESSURIZED.PRESSURIZED.

In order to update the SUB SYSTEM status to PRESSURIZED status during the execution of In order to update the SUB SYSTEM status to PRESSURIZED status during the execution of PRESSURIZATION procedure essentially the following conditions and actions shall be verified and PRESSURIZATION procedure essentially the following conditions and actions shall be verified and followed through:followed through:

1.1. Pipeline pressure “PIT-3134” shall be above the set point..Pipeline pressure “PIT-3134” shall be above the set point..2.2. VBD10-3137 shall be open and operator shall confirm it..VBD10-3137 shall be open and operator shall confirm it..3.3. HP Fuel Gas sub system inlet valve “SDV – 3140“ shall be open.HP Fuel Gas sub system inlet valve “SDV – 3140“ shall be open.4.4. HP Fuel Gas purging shall be carried out.HP Fuel Gas purging shall be carried out.5.5. HP Fuel Gas sub system vent valve “BDV – 3139“ shall be closed when purging TIMEOUT HP Fuel Gas sub system vent valve “BDV – 3139“ shall be closed when purging TIMEOUT

is expired.is expired.6.6. Vent_Monitoring_3 variable status shall be set.Vent_Monitoring_3 variable status shall be set.

The “VENT MONITORING” procedure is "always running“ and if the conditions showed The “VENT MONITORING” procedure is "always running“ and if the conditions showed

hereafter are hereafter are verified during its execution a Vent_Monitoring_3 variable reset shall be carried out to avoid verified during its execution a Vent_Monitoring_3 variable reset shall be carried out to avoid

a process a process fluid contamination:fluid contamination:

1.1. HP Fuel Gas sub system inlet valve “BDV – 3139“ is open & HP Fuel Gas sub system HP Fuel Gas sub system inlet valve “BDV – 3139“ is open & HP Fuel Gas sub system inlet valve inlet valve

“ “SDV – 3140“ is closed.SDV – 3140“ is closed.

In case the operator is operating in manual mode it shall be possible for the operator to In case the operator is operating in manual mode it shall be possible for the operator to force force

VENT_MONITORING_3 STATUS by a dedicated push button which is active / inactive whether VENT_MONITORING_3 STATUS by a dedicated push button which is active / inactive whether all HP all HP

Fuel gas header sub-system vent monitoring conditions are verified.Fuel gas header sub-system vent monitoring conditions are verified.

HP FUEL GAS HEADER SUB-SYSTEMHP FUEL GAS HEADER SUB-SYSTEM

HP FUEL GAS HEADER SUB-SYSTEMHP FUEL GAS HEADER SUB-SYSTEM The process sub-system can be in Pressurized state:The process sub-system can be in Pressurized state:

• PRESSURIZED: Static state with inlet HP fuel valve open and vent line closed.PRESSURIZED: Static state with inlet HP fuel valve open and vent line closed.

Following are showed the possible transitions:Following are showed the possible transitions:• PRESSURIZED state can be achieved by completing the procedure PRESSURIZATION.PRESSURIZED state can be achieved by completing the procedure PRESSURIZATION.

In order to maintain the PRESSURIZED SUB SYSTEM status essentially the following conditions shall be In order to maintain the PRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified :verified :

1.1. HP Fuel Gas sub system inlet valve “SDV – 3140“ shall be open.HP Fuel Gas sub system inlet valve “SDV – 3140“ shall be open.2.2. HP Fuel Gas sub system vent valve “BDV – 3139“ shall be closed.HP Fuel Gas sub system vent valve “BDV – 3139“ shall be closed.3.3. Pipeline pressure “PIT-3134” shall be above the set point.Pipeline pressure “PIT-3134” shall be above the set point.4.4. Vent_Monitoring_3 variable status shall be set.Vent_Monitoring_3 variable status shall be set.

HP FUEL GAS HEADER SUBSYSTEMHP FUEL GAS HEADER SUBSYSTEM

EMERGENCYEMERGENCY

If the ESD system force the SHUTDOWN of SDV-3140 or BDV-3139 the state variable of the If the ESD system force the SHUTDOWN of SDV-3140 or BDV-3139 the state variable of the HP Fuel HP Fuel Gas Gas

Header sub-system Header sub-system that control the valves above mentioned and equipment shall be changed to that control the valves above mentioned and equipment shall be changed to UNKNOWN by UNKNOWN by

means of the state RECOGNITION procedure. means of the state RECOGNITION procedure.

FUEL GAS HP, LP SUBSYSTEMSFUEL GAS HP, LP SUBSYSTEMS The process sub-system can be in Depressurization state:The process sub-system can be in Depressurization state:

• DEPRESSURIZZATION dynamic state which leads to STOPPED PRESSURIZED state. DEPRESSURIZZATION dynamic state which leads to STOPPED PRESSURIZED state. • This state can be always achieved from all the states on the request of operator.This state can be always achieved from all the states on the request of operator.

Following are showed the possible transitions:Following are showed the possible transitions:• DEPRESSURIZATION dynamic state allows the transition from any state to STOPPED DEPRESSURIZATION dynamic state allows the transition from any state to STOPPED DEPRESSURIZED.DEPRESSURIZED.

In order to update the SUB SYSTEM status to STOP DEPRESSURIZED status during the execution of In order to update the SUB SYSTEM status to STOP DEPRESSURIZED status during the execution of DEPRESSURIZATION procedure essentially the following conditions and actions shall be verified and DEPRESSURIZATION procedure essentially the following conditions and actions shall be verified and

followed through:followed through:1.1. Fuel Gas sub system inlet valves “SDV – 3X30“ & “SDV – 3X31“ shall be closed.Fuel Gas sub system inlet valves “SDV – 3X30“ & “SDV – 3X31“ shall be closed.2.2. Fuel Gas sub system vent valve “BDV – 3X40“ shall be open.Fuel Gas sub system vent valve “BDV – 3X40“ shall be open.3.3. Process sub plant pressure “PIT-3X30” shall be below the set point.Process sub plant pressure “PIT-3X30” shall be below the set point.

FUEL GAS HP, LP SUBSYSTEMSFUEL GAS HP, LP SUBSYSTEMS The process sub-system can be in Stopped Depressurized state:The process sub-system can be in Stopped Depressurized state:

• STOPPED DEPRESSURIZED: turbine stopped, SDVs inlet valves “SDV – 3X30“ & “SDV – 3X31“STOPPED DEPRESSURIZED: turbine stopped, SDVs inlet valves “SDV – 3X30“ & “SDV – 3X31“ closed, vent line “BDV – 3X40“closed, vent line “BDV – 3X40“ valves opened.opened.

Following are showed the possible transitions:Following are showed the possible transitions:• STOPPED DEPRESSURIZED state can be achieved by completing the procedure of STOPPED DEPRESSURIZED state can be achieved by completing the procedure of DEPRESSURIZATION.DEPRESSURIZATION.

The SAFETY CONDITION of process sub-system corresponds to the STOPPED DEPRESSURIZED state.The SAFETY CONDITION of process sub-system corresponds to the STOPPED DEPRESSURIZED state.

In order to maintain the STOP DEPRESSURIZED SUB SYSTEM status essentially the following conditions shall be In order to maintain the STOP DEPRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified:verified:

1.1. Fuel Gas sub system inlet valves “SDV – 3X30“ & “SDV – 3X31“ shall be closed.Fuel Gas sub system inlet valves “SDV – 3X30“ & “SDV – 3X31“ shall be closed.2.2. Fuel Gas sub system vent valves “BDV – 3X40“ shall be open.Fuel Gas sub system vent valves “BDV – 3X40“ shall be open.3.3. Process sub plant pressure “PIT-3X30” shall be below the set point.Process sub plant pressure “PIT-3X30” shall be below the set point.

FUEL GAS HP, LP SUBSYSTEMSFUEL GAS HP, LP SUBSYSTEMS The process sub-system can be in Pressurization state:The process sub-system can be in Pressurization state:

• PRESSURIZATION: dynamic state with delivery valves “SDV – 3X30“PRESSURIZATION: dynamic state with delivery valves “SDV – 3X30“ open and vent line “BDV – open and vent line “BDV – 3X40“3X40“ valves

before open (purging) and after closed. It leads to STOPPED PRESSURIZED state.before open (purging) and after closed. It leads to STOPPED PRESSURIZED state.

Following are showed the possible transitions:Following are showed the possible transitions:• PRESSURIZATION dynamic state allows the transition from STOPPED DEPRESSURIZED to PRESSURIZATION dynamic state allows the transition from STOPPED DEPRESSURIZED to

STOPPED STOPPED PRESSURIZED.PRESSURIZED.

In order to update the SUB SYSTEM status to STOP PRESSURIZED status during the execution of In order to update the SUB SYSTEM status to STOP PRESSURIZED status during the execution of PRESSURIZATION PRESSURIZATION

procedure essentially the following conditions and actions shall be verified and followed through:procedure essentially the following conditions and actions shall be verified and followed through:1.1. Manual valves “VBD10-3X10” & “ VBB70” shall be open and operator shall confirm it..Manual valves “VBD10-3X10” & “ VBB70” shall be open and operator shall confirm it..2.2. HP Fuel Gas Header conditions showed hereafter in State Recognized matrix shall be verified..HP Fuel Gas Header conditions showed hereafter in State Recognized matrix shall be verified..3.3. At the beginning Fuel Gas sub system inlet valve “SDV – 3X30“ shall be open. At the beginning Fuel Gas sub system inlet valve “SDV – 3X30“ shall be open. 4.4. Fuel Gas purging shall be carried out . Fuel Gas purging shall be carried out . 5.5. Fuel Gas vent valve “BDV – 3X40“ shall be closed when the purging TIMEOUT is expired. Fuel Gas vent valve “BDV – 3X40“ shall be closed when the purging TIMEOUT is expired. 6.6. Process sub plant pressure “PIT-3X30” shall be above the set point.Process sub plant pressure “PIT-3X30” shall be above the set point.7.7. Vent_Monitoring_1 variable status shall be set.Vent_Monitoring_1 variable status shall be set.8.8. Fuel Gas sub system inlet valve “SDV – 3X30“ shall be closed. Fuel Gas sub system inlet valve “SDV – 3X30“ shall be closed.

FUEL GAS HP, LP SUBSYSTEMSFUEL GAS HP, LP SUBSYSTEMS

The “VENT MONITORING” procedure is "always running“ and if the conditions showed hereafter are verified The “VENT MONITORING” procedure is "always running“ and if the conditions showed hereafter are verified during its execution a Vent_Monitoring_1 variable reset shall be carried out to avoid a process fluid during its execution a Vent_Monitoring_1 variable reset shall be carried out to avoid a process fluid contamination :contamination :

1.1. Fuel Gas process sub plant pressure “PIT – 3X30“ is below the threshold.Fuel Gas process sub plant pressure “PIT – 3X30“ is below the threshold.2.2. Fuel Gas sub system inlet valve “SDV – 3X30“ is open & Hp Fuel Gas Header sub system is not Fuel Gas sub system inlet valve “SDV – 3X30“ is open & Hp Fuel Gas Header sub system is not

purged ( VENT_MONITORING_3 shall be reset ).purged ( VENT_MONITORING_3 shall be reset ).

In case the operator is operating in manual mode it shall be possible for the operator to force In case the operator is operating in manual mode it shall be possible for the operator to force VENT_MONITORING_1 STATUS by a dedicated push button which is active / inactive whether all Fuel gas VENT_MONITORING_1 STATUS by a dedicated push button which is active / inactive whether all Fuel gas header sub-system vent monitoring conditions are verified.header sub-system vent monitoring conditions are verified.

FUEL GAS HP, LP SUBSYSTEMSFUEL GAS HP, LP SUBSYSTEMS The process sub-system can be in Stopped Pressurized state:The process sub-system can be in Stopped Pressurized state:

• STOPPED PRESSURIZED: turbine stopped, SDVs inlet STOPPED PRESSURIZED: turbine stopped, SDVs inlet valves “SDV – 3X30“ & “SDV – 3X31“ “SDV – 3X30“ & “SDV – 3X31“ closed, vent line closed, vent line

valve “BDV – 3X40“ closed.valve “BDV – 3X40“ closed.

Following are showed the possible transitions:Following are showed the possible transitions:• STOPPED PRESSURIZED state can be achieved by completing the procedures of STOPPING or STOPPED PRESSURIZED state can be achieved by completing the procedures of STOPPING or PRESSURIZATION.PRESSURIZATION.

In order to maintain the STOPPED PRESSURIZED SUB SYSTEM status essentially the following conditions shall In order to maintain the STOPPED PRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified :be verified :

1.1. Fuel Gas sub system inlet valves “SDV – 3X30“ & “SDV – 3X31“ shall be closed.Fuel Gas sub system inlet valves “SDV – 3X30“ & “SDV – 3X31“ shall be closed.2.2. Fuel Gas sub system vent valve “BDV – 3X40“ shall be closed.Fuel Gas sub system vent valve “BDV – 3X40“ shall be closed.3.3. Vent_Monitoring_1 variable status shall be set.Vent_Monitoring_1 variable status shall be set.


The process sub-system can be in Starting state:The process sub-system can be in Starting state:• STARTING: dynamic state whom leads to RUN HP/HL state.STARTING: dynamic state whom leads to RUN HP/HL state.

Following are showed the possible transitions:Following are showed the possible transitions:• STARTING dynamic state allows the transition from STOPPED PRESSURIZED to RUN HP/LP.STARTING dynamic state allows the transition from STOPPED PRESSURIZED to RUN HP/LP.

In order to update the SUB SYSTEM status to RUN HP or RUN LP during the execution of START procedure In order to update the SUB SYSTEM status to RUN HP or RUN LP during the execution of START procedure essentially the following conditions and actions shall be verified and followed through:essentially the following conditions and actions shall be verified and followed through:

1.1. If LP Fuel Gas Header conditions showed hereafter in State Recognized matrix are verified Fuel Gas If LP Fuel Gas Header conditions showed hereafter in State Recognized matrix are verified Fuel Gas sub system inlet valve “SDV – 3X31“ shall be open.sub system inlet valve “SDV – 3X31“ shall be open.

2.2. If the conditions regarding LP Fuel Gas Header are not verified HP Fuel Gas Header conditions If the conditions regarding LP Fuel Gas Header are not verified HP Fuel Gas Header conditions showed hereafter in State Recognized matrix shall be verified & Fuel Gas sub system inlet valve showed hereafter in State Recognized matrix shall be verified & Fuel Gas sub system inlet valve “SDV – 3X30“ shall be open..“SDV – 3X30“ shall be open..

3.3. Process sub plant pressure “PIT-3X30” shall be above the set point.Process sub plant pressure “PIT-3X30” shall be above the set point.

FUEL GAS HP, LP SUBSYSTEMSFUEL GAS HP, LP SUBSYSTEMS The process sub-system can be in Run HP state:The process sub-system can be in Run HP state:

• RUN HP: operating functioning with gas feeding from the H.P. FUEL GAS HEADER.RUN HP: operating functioning with gas feeding from the H.P. FUEL GAS HEADER.

Following are showed the possible transitions:Following are showed the possible transitions:• RUN HP can be achieved by completing the procedures of STARTING or SWITCHING.RUN HP can be achieved by completing the procedures of STARTING or SWITCHING.

In order to maintain the RUN HP SUB SYSTEM status essentially the following conditions shall be verified:In order to maintain the RUN HP SUB SYSTEM status essentially the following conditions shall be verified:• Vent_Monitoring_1 variable status shall be set.Vent_Monitoring_1 variable status shall be set.• Pipeline pressure “PIT-3X30” shall be above the set point. Pipeline pressure “PIT-3X30” shall be above the set point. • Fuel Gas sub system vent valve “BDV – 3X40“ shall be closed.Fuel Gas sub system vent valve “BDV – 3X40“ shall be closed. • Fuel Gas sub system inlet valve “SDV – 3X31“ shall be closed and “SDV – 3X30“ valve shall be Fuel Gas sub system inlet valve “SDV – 3X31“ shall be closed and “SDV – 3X30“ valve shall be

open.open. • If LP Fuel Gas Header conditions showed hereafter in State Recognized matrix are verified a If LP Fuel Gas Header conditions showed hereafter in State Recognized matrix are verified a

calling to calling to • SWITCHING procedure shall be carried out.SWITCHING procedure shall be carried out.• If the conditions regarding LP Fuel Gas Header are not verified, HP Fuel Gas Header If the conditions regarding LP Fuel Gas Header are not verified, HP Fuel Gas Header

conditions showed conditions showed • hereafter in State Recognized matrix shall be verified & Fuel Gas sub system inlet valve “SDV hereafter in State Recognized matrix shall be verified & Fuel Gas sub system inlet valve “SDV

– 3X30“ shall be open.– 3X30“ shall be open.• Turbine actual speed shall be higher than set point.Turbine actual speed shall be higher than set point.• TRIGGER_x variable status shall be set if the Turbine actual speed is higher than set point. TRIGGER_x variable status shall be set if the Turbine actual speed is higher than set point.

HPHP

The process sub-system can be in Run LP state:The process sub-system can be in Run LP state:• RUN LP: operating functioning with gas feeding from the L.P. FUEL GAS HEADER.RUN LP: operating functioning with gas feeding from the L.P. FUEL GAS HEADER.

Following are showed the possible transitions:Following are showed the possible transitions:• RUN LP can be achieved by completing the procedures of STARTING or SWITCHING.RUN LP can be achieved by completing the procedures of STARTING or SWITCHING.

In order to maintain the RUN LP SUB SYSTEM status essentially the following conditions shall be verified :In order to maintain the RUN LP SUB SYSTEM status essentially the following conditions shall be verified :1.1. Vent_Monitoring_1 variable status shall be set.Vent_Monitoring_1 variable status shall be set.2.2. Pipeline pressure “PIT-31X4” shall be above the set point. Pipeline pressure “PIT-31X4” shall be above the set point. 3.3. Fuel Gas sub system vent valve “BDV – 3X40“ shall be closed.Fuel Gas sub system vent valve “BDV – 3X40“ shall be closed. 4.4. Fuel Gas sub system inlet valve “SDV – 3X31“ shall be open and “SDV – 3X30“ valve shall be closed. Fuel Gas sub system inlet valve “SDV – 3X31“ shall be open and “SDV – 3X30“ valve shall be closed. 5.5. If the conditions regarding LP Fuel Gas Header are NOT verified, HP Fuel Gas Header conditions If the conditions regarding LP Fuel Gas Header are NOT verified, HP Fuel Gas Header conditions

showed hereafter in State Recognized matrix shall be verified and a calling to SWITCHING procedure showed hereafter in State Recognized matrix shall be verified and a calling to SWITCHING procedure shall be carried out.shall be carried out.

6.6. Turbine actual speed shall be higher than set point.Turbine actual speed shall be higher than set point.7.7. TRIGGER_x variable status shall be set if Turbine actual speed is higher than set point.TRIGGER_x variable status shall be set if Turbine actual speed is higher than set point.


LPLP

FUEL GAS HP, LP SUBSYSTEMSFUEL GAS HP, LP SUBSYSTEMS The timer T91 is the maximum time that the fuel gas system can operate in RUN status with the Turbine The timer T91 is the maximum time that the fuel gas system can operate in RUN status with the Turbine

stopped. stopped. If the timer T91 expires the Fuel Gas status is forced to STOP immediately.If the timer T91 expires the Fuel Gas status is forced to STOP immediately.

The flag named TRIGGER_x is set when the turbine is started ; from this time, the timer has no effect, The flag named TRIGGER_x is set when the turbine is started ; from this time, the timer has no effect, and if again and if again

the turbine is stopped, the fuel gas system is forced to STOPPING immediately.the turbine is stopped, the fuel gas system is forced to STOPPING immediately.

The flag TRIGGER_x shall be reset automatically if the state is not RUN or UNKNOWN.The flag TRIGGER_x shall be reset automatically if the state is not RUN or UNKNOWN.

To avoid the risk to close the fuel gas while the turbine is running, if a turbine speed state is not defined To avoid the risk to close the fuel gas while the turbine is running, if a turbine speed state is not defined (serial link in (serial link in

bad status) the trigger function is disabled.bad status) the trigger function is disabled.

HPHP


SWITCHING PROCEDURESWITCHING PROCEDURE

The process sub-system can be in Run HP state:The process sub-system can be in Run HP state:• SWITCHING: dynamic state which leads from RUN_HP state to RUN_LP state and vice versa.SWITCHING: dynamic state which leads from RUN_HP state to RUN_LP state and vice versa.

Following are showed the possible transitions:Following are showed the possible transitions:• SWITCHING procedure allow transition from RUN HP to RUN LP (and vice versa) according to SWITCHING procedure allow transition from RUN HP to RUN LP (and vice versa) according to

process process conditions. When it is possible the system give the preference to RUN_LP mode.conditions. When it is possible the system give the preference to RUN_LP mode.

In order to update the SUB SYSTEM status to RUN HP or RUN LP during the execution of Switching In order to update the SUB SYSTEM status to RUN HP or RUN LP during the execution of Switching procedure essentially procedure essentially

the following conditions and actions shall be verified and followed through:the following conditions and actions shall be verified and followed through:

• Every time a switching procedure calling is carried out when HP Fuel Gas sub system actual Every time a switching procedure calling is carried out when HP Fuel Gas sub system actual status is RUN status is RUN

HP the HP Fuel Gas sub system inlet valve “SDV – 3X31“ shall be open & the HP Fuel Gas sub HP the HP Fuel Gas sub system inlet valve “SDV – 3X31“ shall be open & the HP Fuel Gas sub system inlet system inlet

valve “SDV – 3X30“ shall be closed.valve “SDV – 3X30“ shall be closed.

• Every time a switching procedure calling is carried out when HP Fuel Gas sub system actual Every time a switching procedure calling is carried out when HP Fuel Gas sub system actual status is RUN status is RUN

LP the HP Fuel Gas sub system inlet valve “SDV – 3X30“ shall be open & the HP Fuel Gas sub LP the HP Fuel Gas sub system inlet valve “SDV – 3X30“ shall be open & the HP Fuel Gas sub system inlet system inlet

valve “SDV – 3X31“ shall be closed.valve “SDV – 3X31“ shall be closed.

RUN HPRUN HP

RUN LPRUN LP

FUEL GAS HP, LP SUBSYSTEMSFUEL GAS HP, LP SUBSYSTEMS The process sub-system can be in Stop state:The process sub-system can be in Stop state:

• STOPPING: dynamic state whom leads to STOPPED PRESSURIZED state.STOPPING: dynamic state whom leads to STOPPED PRESSURIZED state.

Following are showed the possible transitions:Following are showed the possible transitions:• STOPPING dynamic state allows the transition from RUN LP/HP to STOPPED PRESSURIZED.STOPPING dynamic state allows the transition from RUN LP/HP to STOPPED PRESSURIZED.

In order to update the SUB SYSTEM status to STOP PRESSURIZED during the execution of STOP procedure essentially the In order to update the SUB SYSTEM status to STOP PRESSURIZED during the execution of STOP procedure essentially the following conditions and actions shall be verified and followed through:following conditions and actions shall be verified and followed through:

1.1. Fuel Gas sub system inlet valves “SDV – 3X30“ & “SDV – 3X31“ shall be closed.Fuel Gas sub system inlet valves “SDV – 3X30“ & “SDV – 3X31“ shall be closed.

LP FUEL SELECTORLP FUEL SELECTOR

A SOFTWARE SELECTOR always active is foreseen that enable/disable the automatic switching from A SOFTWARE SELECTOR always active is foreseen that enable/disable the automatic switching from RUN_HP to RUN_LP operations when the operator push the button showed hereafter.RUN_HP to RUN_LP operations when the operator push the button showed hereafter.

If the selector is disabled by means the operator when the operation is just in RUN_LP mode, the If the selector is disabled by means the operator when the operation is just in RUN_LP mode, the transition to RUN_HP mode is forced.transition to RUN_HP mode is forced.

Furthermore when the selector is disable by means the operator the STARTING operation will be Furthermore when the selector is disable by means the operator the STARTING operation will be performed only by using HP fuel gas header.performed only by using HP fuel gas header.


ELECTRIC FUEL GAS HEATERELECTRIC FUEL GAS HEATER A stand alone procedure manages the fuel gas heater. A stand alone procedure manages the fuel gas heater. When the LOCAL/REMOTE switch of the Heater Control Panel is in LOCAL, an alarm shall be generated, When the LOCAL/REMOTE switch of the Heater Control Panel is in LOCAL, an alarm shall be generated,

the TIC controller shall be disabled and the ON/OFF command to the heater shall be in OFF state. the TIC controller shall be disabled and the ON/OFF command to the heater shall be in OFF state. When the LOCAL/REMOTE switch of the Heater Control Panel is in REMOTE position, the fuel gas heater When the LOCAL/REMOTE switch of the Heater Control Panel is in REMOTE position, the fuel gas heater

shall be started if the following conditions are satisfied:shall be started if the following conditions are satisfied:

1.1. Fuel gas flow rate “FT-3X14” shall be higher than set point.Fuel gas flow rate “FT-3X14” shall be higher than set point.2.2. One of the SDV-3X30 and SDV-3X31 valves shall be open or both valves shall be open.One of the SDV-3X30 and SDV-3X31 valves shall be open or both valves shall be open.3.3. The set point of electric fuel gas heater depends on the SDV valve opened: the higher set The set point of electric fuel gas heater depends on the SDV valve opened: the higher set

point is point is related to SDV-3931 opened.related to SDV-3931 opened.

If there is a switching between the SDV valves the set point changes accordingly.If there is a switching between the SDV valves the set point changes accordingly.

ELECTRIC FUEL GAS HEATERELECTRIC FUEL GAS HEATER

When the LOCAL/REMOTE switch of the Heater Control Panel is in LOCAL or Heater Control Panel is When the LOCAL/REMOTE switch of the Heater Control Panel is in LOCAL or Heater Control Panel is switched off the TIC controller AUTO or CASCATE operating mode shall be disabled and the TIC controller switched off the TIC controller AUTO or CASCATE operating mode shall be disabled and the TIC controller MANUAL operating mode shall be enable.MANUAL operating mode shall be enable.

In Manual MODE the operator can change the controller output.In Manual MODE the operator can change the controller output. In AUTO mode the operator can changes the controller set point in a predetermined range. In AUTO mode the operator can changes the controller set point in a predetermined range. In CASCATE mode the set point is fixed.In CASCATE mode the set point is fixed.


EMERGENCYEMERGENCY

If the ESD system force the SHUTDOWN of SDV-3X30 or SDV-3X31 or BDV-3X40 valves the state If the ESD system force the SHUTDOWN of SDV-3X30 or SDV-3X31 or BDV-3X40 valves the state variable of the variable of the Fuel Gas HP-LP sub-systems Fuel Gas HP-LP sub-systems that control the valves above mentioned and equipment that control the valves above mentioned and equipment shall be changed to UNKNOWN by means of the state RECOGNITION procedure. shall be changed to UNKNOWN by means of the state RECOGNITION procedure.

SEAL GAS HP, LP SUBSYSTEMSSEAL GAS HP, LP SUBSYSTEMS The process sub-system can be in Depressurization state:The process sub-system can be in Depressurization state:

• DEPRESSURIZATION: Dynamic state DEPRESSURIZATION: Dynamic state which allows to vent process fluid. which allows to vent process fluid.

Following are showed the possible transitions:Following are showed the possible transitions:• DEPRESSURIZATION dynamic state allows the transition from any state to DEPRESSURIZATION dynamic state allows the transition from any state to

DEPRESSURIZED.DEPRESSURIZED.

In order to update the SUB SYSTEM status to DEPRESSURIZED status during the execution of In order to update the SUB SYSTEM status to DEPRESSURIZED status during the execution of DEPRESSURIZATION procedure essentially the following conditions and actions shall be verified and DEPRESSURIZATION procedure essentially the following conditions and actions shall be verified and followed through:followed through:

1.1. Gas compressor LP A,B – HP A,B shall not be pressurized (ST_Case_Pressurized signal shall Gas compressor LP A,B – HP A,B shall not be pressurized (ST_Case_Pressurized signal shall be reset)..be reset)..

2.2. Seal Gas sub system inlet valve “SDV – 3X50“ shall be closed.Seal Gas sub system inlet valve “SDV – 3X50“ shall be closed.3.3. Seal Gas vent valve “BDV – 3X52“ shall be open. Seal Gas vent valve “BDV – 3X52“ shall be open. 4.4. Process sub plant pressure “PIT-3X53” shall be lower than set point. Process sub plant pressure “PIT-3X53” shall be lower than set point.

SEAL GAS HP, LP SUBSYSTEMSSEAL GAS HP, LP SUBSYSTEMS The process sub-system can be in Depressurized state:The process sub-system can be in Depressurized state:

• DEPRESSURIZED: Static state with inlet seal gas feed valve “SDV – 3X50“DEPRESSURIZED: Static state with inlet seal gas feed valve “SDV – 3X50“ closed closed (properly this state certifies a NOT-PRESSURIZED process sub-system).(properly this state certifies a NOT-PRESSURIZED process sub-system).



SAFETY CONDITION of process sub-system, that represents the final condition of automatic SAFETY CONDITION of process sub-system, that represents the final condition of automatic protection procedures, coincides with DEPRESSURIZED state.protection procedures, coincides with DEPRESSURIZED state.

In order to maintain the DEPRESSURIZED SUB SYSTEM status essentially the following conditions In order to maintain the DEPRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified :shall be verified :

1.1. Seal Gas sub system inlet valve “SDV – 3X50“ shall be closed.Seal Gas sub system inlet valve “SDV – 3X50“ shall be closed.2.2. Seal Gas vent valve “BDV – 3X52“ shall be open. Seal Gas vent valve “BDV – 3X52“ shall be open. 3.3. Process sub plant pressure “PIT-3X53” shall be lower than set point. Process sub plant pressure “PIT-3X53” shall be lower than set point.

SEAL GAS HP, LP SUBSYSTEMSSEAL GAS HP, LP SUBSYSTEMS The process sub-system can be in Pressurization state:The process sub-system can be in Pressurization state:

• PRESSURIZATION: Dynamic state PRESSURIZATION: Dynamic state which allows the purging of trapped air and the which allows the purging of trapped air and the pressurization of process sub-system.pressurization of process sub-system.

Following are showed the possible transitions:Following are showed the possible transitions:• PRESSURIZATION dynamic state allows the transition from DEPRESSURIZED to PRESSURIZATION dynamic state allows the transition from DEPRESSURIZED to

PRESSURIZED.PRESSURIZED.

In order to update the SUB SYSTEM status to PRESSURIZED status the execution of In order to update the SUB SYSTEM status to PRESSURIZED status the execution of PRESSURIZATION procedure essentially the following conditions and actions shall be verified and PRESSURIZATION procedure essentially the following conditions and actions shall be verified and followed through:followed through:

1.1. HP Fuel Gas good conditions shall be verified.HP Fuel Gas good conditions shall be verified.2.2. Seal Gas sub system inlet valve “SDV – 3X50“ shall be open.Seal Gas sub system inlet valve “SDV – 3X50“ shall be open.3.3. Seal Gas purging shall be carried out . Seal Gas purging shall be carried out . 4.4. Seal Gas vent valve “BDV – 3X52“ shall be closed when the purging TIMEOUT is expired. Seal Gas vent valve “BDV – 3X52“ shall be closed when the purging TIMEOUT is expired. 5.5. Process sub plant pressure “PIT-3X53” shall be above the set point.Process sub plant pressure “PIT-3X53” shall be above the set point.6.6. Vent_Monitoring_2 variable status shall be set.Vent_Monitoring_2 variable status shall be set.7.7. Process sub plant pressure “PIT-3X53” shall be above the set point.Process sub plant pressure “PIT-3X53” shall be above the set point.

SEAL GAS HP, LP SUBSYSTEMSSEAL GAS HP, LP SUBSYSTEMS The “VENT MONITORING” procedure is "always running“ and if the conditions showed The “VENT MONITORING” procedure is "always running“ and if the conditions showed

hereafter are hereafter are verified during its execution a Vent_Monitoring_2 variable reset shall be carried out to avoid verified during its execution a Vent_Monitoring_2 variable reset shall be carried out to avoid

a process a process fluid contamination :fluid contamination :

1.1. Seal Gas process sub plant pressure “PIT – 3X53“ is below the threshold.Seal Gas process sub plant pressure “PIT – 3X53“ is below the threshold.2.2. Seal Gas sub system inlet valve “SDV – 3X50“ is open & Hp Fuel Gas Header sub Seal Gas sub system inlet valve “SDV – 3X50“ is open & Hp Fuel Gas Header sub

system is not system is not purged.purged.

In case the operator is operating in manual mode it shall be possible for the operator to In case the operator is operating in manual mode it shall be possible for the operator to force force

VENT_MONITORING_2 STATUS by a dedicated push button which is active / inactive whether VENT_MONITORING_2 STATUS by a dedicated push button which is active / inactive whether all HP all HP

Fuel gas header sub-system vent monitoring conditions are verified.Fuel gas header sub-system vent monitoring conditions are verified.

SEAL GAS HP, LP SUBSYSTEMSSEAL GAS HP, LP SUBSYSTEMS The process sub-system can be in Pressurized state:The process sub-system can be in Pressurized state:

• PRESSURIZED: Static state with seal gas inlet feed valve open and seal gas vent valve PRESSURIZED: Static state with seal gas inlet feed valve open and seal gas vent valve closed.closed.

Following are showed the possible transitions:Following are showed the possible transitions:• PRESSURIZED state can be achieved by completing the procedure of PRESSURIZATION. PRESSURIZED state can be achieved by completing the procedure of PRESSURIZATION.

In order to maintain the PRESSURIZED SUB SYSTEM status essentially the following conditions shall In order to maintain the PRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified :be verified :

1.1. Seal Gas sub system inlet valve “SDV – 3X50“ shall be open.Seal Gas sub system inlet valve “SDV – 3X50“ shall be open.2.2. Seal Gas sub system vent valve “BDV – 3X52“ shall be closed.Seal Gas sub system vent valve “BDV – 3X52“ shall be closed.3.3. Process sub plant pressure “PIT-3X53” shall be above the set point.Process sub plant pressure “PIT-3X53” shall be above the set point.

SEAL GAS HP, LP SUBSYSTEMSSEAL GAS HP, LP SUBSYSTEMS

EMERGENCYEMERGENCY

If the ESD system force the SHUTDOWN of SDV-3X50 or BDV-3X52 the state variable of the If the ESD system force the SHUTDOWN of SDV-3X50 or BDV-3X52 the state variable of the Seal Seal Gas HP-LP sub-systems Gas HP-LP sub-systems that control the valves above mentioned and equipment shall be that control the valves above mentioned and equipment shall be changed to UNKNOWN by means of the state RECOGNITION procedure. changed to UNKNOWN by means of the state RECOGNITION procedure.

The process sub-system can be in Depressurization state:The process sub-system can be in Depressurization state:• DEPRESSURIZATION: dynamic state which leads to STOP DEPRESSURIZED state. DEPRESSURIZATION: dynamic state which leads to STOP DEPRESSURIZED state.

Following are showed the possible transitions:Following are showed the possible transitions:• DEPRESSURIZATION dynamic state allows the transition from any state to STOP DEPRESSURIZATION dynamic state allows the transition from any state to STOP

DEPRESSURIZED. DEPRESSURIZED.


1.1. Slug Catcher inlet valve “SDV-3111” shall be closedSlug Catcher inlet valve “SDV-3111” shall be closed2.2. Loading line bypass valve “SDV-3112” shall be closed.Loading line bypass valve “SDV-3112” shall be closed.3.3. Discharge pipeline vent valve “BDV-3135” shall be open.Discharge pipeline vent valve “BDV-3135” shall be open.4.4. Station delivery line valve “SDV-3134” shall be closed.Station delivery line valve “SDV-3134” shall be closed.5.5. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be under the set point. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be under the set point. 6.6. The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be under the set The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be under the set

point.point.7.7. The fluid pressure “PIT-3123” within the Filter Separator shall be under the set point.The fluid pressure “PIT-3123” within the Filter Separator shall be under the set point.8.8. The fluid pressure “PIT-3133” at the station discharge shall be under the set point.The fluid pressure “PIT-3133” at the station discharge shall be under the set point.9.9. The PID-3133 regulator shall be set in AUTO with a predetermined set point.The PID-3133 regulator shall be set in AUTO with a predetermined set point.

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS The process sub-system can be in Pressurized state:The process sub-system can be in Pressurized state:

• STOP DEPRESSURIZED: turbine stopped with outlet valves “SDV-3134”STOP DEPRESSURIZED: turbine stopped with outlet valves “SDV-3134” closed, inlet valve “SDV-closed, inlet valve “SDV-3111”3111” closed, vent line “BDV-3135”closed, vent line “BDV-3135” valve opened. opened.

Following are showed the possible transitions:Following are showed the possible transitions:• STOP DEPRESSURIZED state can be achieved by completing the procedure of STOP DEPRESSURIZED state can be achieved by completing the procedure of

DEPRESSURIZATION. DEPRESSURIZATION.

The SAFETY CONDITION of process sub-system (which is the final condition of the automatic safety The SAFETY CONDITION of process sub-system (which is the final condition of the automatic safety procedures) corresponds to the STOP DEPRESSURIZED state.procedures) corresponds to the STOP DEPRESSURIZED state.

In order to maintain the STOP DEPRESSURIZED SUB SYSTEM status essentially the following conditions shall In order to maintain the STOP DEPRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified:be verified:

1.1. Loading line bypass valve “SDV-3112” shall be closed.Loading line bypass valve “SDV-3112” shall be closed.2.2. Slug Catcher inlet valve “SDV-3111” shall be closed.Slug Catcher inlet valve “SDV-3111” shall be closed.3.3. Station delivery line valve “SDV-3134” shall be closed.Station delivery line valve “SDV-3134” shall be closed.4.4. Discharge pipeline vent valve “BDV-3135” shall be open.Discharge pipeline vent valve “BDV-3135” shall be open.5.5. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be lower than set point. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be lower than set point. 6.6. The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be lower than set The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be lower than set

point.point.7.7. The fluid pressure “PIT-3123” within the Filter Separator shall be lower than set point. The fluid pressure “PIT-3123” within the Filter Separator shall be lower than set point.

8.8. The fluid pressure “PIT-3133” at the station discharge shall be under the set point.The fluid pressure “PIT-3133” at the station discharge shall be under the set point.

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS The process sub-system can be in Pressurization state:The process sub-system can be in Pressurization state:

• PRESSURIZATION: dynamic state which allows the purging of trapped air and the pressurization of PRESSURIZATION: dynamic state which allows the purging of trapped air and the pressurization of process sub-system. It leads to STOP PRESSURIZED state.process sub-system. It leads to STOP PRESSURIZED state.

Following are showed the possible transitions:Following are showed the possible transitions:• PRESSURIZATION dynamic state allows the transition from STOP DEPRESSURIZED to STOP PRESSURIZATION dynamic state allows the transition from STOP DEPRESSURIZED to STOP

PRESSURIZED. PRESSURIZED.

In order to update the SUB SYSTEM status to STOPPED PRESSURIZED status during the execution of In order to update the SUB SYSTEM status to STOPPED PRESSURIZED status during the execution of PRESSURIZATION procedure essentially the following conditions and actions shall be verified and followed through:PRESSURIZATION procedure essentially the following conditions and actions shall be verified and followed through:

• Manual valves “VBD10-3125”, “VBD10-3127”, “VBD10-3126” on MAK-3120 filter separator Skid , Manual valves “VBD10-3125”, “VBD10-3127”, “VBD10-3126” on MAK-3120 filter separator Skid , “VBD10-3615”“VBD10-3615” ,

“ “VBD10-3616”, VBD10-3616”, “VBD10-3617” on Dehydration Skid and “VBD10-3621”, “VBD10-3142”, “VBD10-“VBD10-3617” on Dehydration Skid and “VBD10-3621”, “VBD10-3142”, “VBD10-3143” shall be closed and valves3143” shall be closed and valves on Main Header shall be open and operator shall confirm it.. on Main Header shall be open and operator shall confirm it..

• At the beginning Loading line bypass valve “SDV-3112” shall be open & fluid pressure “PIT-3113”, At the beginning Loading line bypass valve “SDV-3112” shall be open & fluid pressure “PIT-3113”,

“ “PIT-3114”, “PIT-3115”, “PIT-3123”, “PIT-3133 shall be lower than set point. PIT-3114”, “PIT-3115”, “PIT-3123”, “PIT-3133 shall be lower than set point. • Main Header sub system purging shall be carried out . Main Header sub system purging shall be carried out . • Discharge pipeline vent valve “BDV–3135“ shall be closed when the purging TIMEOUT is expired. Discharge pipeline vent valve “BDV–3135“ shall be closed when the purging TIMEOUT is expired. • Differential pressure “PDS-3112” across the Slug Catcher inlet valve “SDV-3111” shall be lower than Differential pressure “PDS-3112” across the Slug Catcher inlet valve “SDV-3111” shall be lower than

set point.set point.• Slug Catcher inlet valve “SDV-3111” shall be open.Slug Catcher inlet valve “SDV-3111” shall be open.• Loading line bypass valve “SDV-3112” shall be closed.Loading line bypass valve “SDV-3112” shall be closed.• The fluid pressure “PIT-3113”, “PIT-3114”, “PIT-3115”, “PIT-3123”, “PIT-3133 shall be higher than The fluid pressure “PIT-3113”, “PIT-3114”, “PIT-3115”, “PIT-3123”, “PIT-3133 shall be higher than

set point.set point.• Vent_Monitoring_4 variable status shall be set.Vent_Monitoring_4 variable status shall be set.• The PID-3133 industrial regulator shall be set in AUTO with a predetermined set point.The PID-3133 industrial regulator shall be set in AUTO with a predetermined set point.

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS If the MAK-3120 is BY-PASSED, during the execution of PRESSURIZATION sequence, it is requested to If the MAK-3120 is BY-PASSED, during the execution of PRESSURIZATION sequence, it is requested to

operator the operator the confirmation of VBD10-3125 CLOSED, VBD10-3127 CLOSED, VBD10-3126 OPEN.confirmation of VBD10-3125 CLOSED, VBD10-3127 CLOSED, VBD10-3126 OPEN. If the MAK-3120 is ON-DUTY ,during the execution of PRESSURIZATION sequence, it is requested to If the MAK-3120 is ON-DUTY ,during the execution of PRESSURIZATION sequence, it is requested to operator the confirmation of: VBD10-3125 OPEN, VBD10-3127 OPEN, VBD10-3126 CLOSED. operator the confirmation of: VBD10-3125 OPEN, VBD10-3127 OPEN, VBD10-3126 CLOSED. Operator can by-pass the filter separator by insert a password into the ESD.Operator can by-pass the filter separator by insert a password into the ESD. This password switch off the checking of DCS and ESD on the filter separator to avoid possible alarms.This password switch off the checking of DCS and ESD on the filter separator to avoid possible alarms. The same password has to be inserted to come back, to enable again DCS and ESD checking.The same password has to be inserted to come back, to enable again DCS and ESD checking. When checking is enabled again the DCS shall leads the sub system status to unknown and SRP shall be When checking is enabled again the DCS shall leads the sub system status to unknown and SRP shall be

run to recognize the plant sub-system state.run to recognize the plant sub-system state.

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS If the Glycol Dehydration Skid is BY-PASSED, during the execution of PRESSURIZATION sequence, it is If the Glycol Dehydration Skid is BY-PASSED, during the execution of PRESSURIZATION sequence, it is

requested to requested to operator the confirmation of: VBD10-3616 CLOSED, VBD10-3617 CLOSED, VBD10-3615 OPENoperator the confirmation of: VBD10-3616 CLOSED, VBD10-3617 CLOSED, VBD10-3615 OPEN Operator can by-pass the Glycol Dehydration Skid by insert a password into the ESD.Operator can by-pass the Glycol Dehydration Skid by insert a password into the ESD. This password switch off the checking of DCS and ESD on the filter separator to avoid possible alarms.This password switch off the checking of DCS and ESD on the filter separator to avoid possible alarms. The same password has to be inserted to come back, to enable again DCS and ESD checking.The same password has to be inserted to come back, to enable again DCS and ESD checking. When checking is enabled again the DCS shall leads the sub system status to unknown and SRP shall be run When checking is enabled again the DCS shall leads the sub system status to unknown and SRP shall be run

to recognize the plant sub-system state.to recognize the plant sub-system state. However this password shall not take effect on the glycol regeneration utility system.However this password shall not take effect on the glycol regeneration utility system. If the Glycol Dehydration Skid is ON-DUTY, during the execution of PRESSURIZATION sequence, it is If the Glycol Dehydration Skid is ON-DUTY, during the execution of PRESSURIZATION sequence, it is

requested to requested to operator the confirmation of: VBD10-3616 OPEN, VBD10-3617 OPEN, VBD10-3615 CLOSEDoperator the confirmation of: VBD10-3616 OPEN, VBD10-3617 OPEN, VBD10-3615 CLOSED

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS A dedicated procedure "always running“A dedicated procedure "always running“ manages the drainage operations of the discharge filter separator manages the drainage operations of the discharge filter separator

and the slug catcher. and the slug catcher. These procedures maintain the liquid between two defined level by operating the discharge filter separator These procedures maintain the liquid between two defined level by operating the discharge filter separator

control valves LV-3121A and LV-3122A and the slug catcher control valves LV-3114A. control valves LV-3121A and LV-3122A and the slug catcher control valves LV-3114A. Hysteresis is necessary to avoid continuous changeover. Hysteresis is necessary to avoid continuous changeover. A PID industrial controls the valve PV-3133 which regulates the pressure at the station discharge.A PID industrial controls the valve PV-3133 which regulates the pressure at the station discharge.


The “VENT MONITORING” procedure is "always running“ and if the following conditions are verified The “VENT MONITORING” procedure is "always running“ and if the following conditions are verified during its execution a Vent_Monitoring _4 variable reset shall be carried out to avoid a process fluid during its execution a Vent_Monitoring _4 variable reset shall be carried out to avoid a process fluid contamination :contamination :

1.1. The fluid pressure “PIT-3113” upstream the Slug Catcher is lower than set point. The fluid pressure “PIT-3113” upstream the Slug Catcher is lower than set point. 2.2. The fluid pressure “PIT-3114” or “PIT-3115” in the Inter stage Headers is lower than set The fluid pressure “PIT-3114” or “PIT-3115” in the Inter stage Headers is lower than set

point.point.3.3. The fluid pressure “PIT-3123” within the Filter Separator is lower than set point.The fluid pressure “PIT-3123” within the Filter Separator is lower than set point.4.4. The fluid pressure “PIT-3133” at the station discharge is lower than set point.The fluid pressure “PIT-3133” at the station discharge is lower than set point.

In case the operator is operating in manual mode it shall be possible for the operator to force In case the operator is operating in manual mode it shall be possible for the operator to force VENT_MONITORING_4 STATUS by a dedicated push button which is active / inactive whether all HP VENT_MONITORING_4 STATUS by a dedicated push button which is active / inactive whether all HP Fuel gas header sub-system vent monitoring conditions are verified.Fuel gas header sub-system vent monitoring conditions are verified.

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS The process sub-system can be in Stop Pressurized state:The process sub-system can be in Stop Pressurized state:

• STOP PRESSURIZED: turbine stopped, outlet valves “SDV-3134”STOP PRESSURIZED: turbine stopped, outlet valves “SDV-3134” closed, inlet valve “SDV-3111”closed, inlet valve “SDV-3111” opened, opened,

vent line “BDV-3135”vent line “BDV-3135” valve closed. closed. Following are showed the possible transitions:Following are showed the possible transitions:

• STOP PRESSURIZED state can be achieved by completing the procedures of STOPPING and STOP PRESSURIZED state can be achieved by completing the procedures of STOPPING and PRESSURIZATION.PRESSURIZATION.

In order to maintain the STOP PRESSURIZED SUB SYSTEM status essentially the following conditions shall be In order to maintain the STOP PRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified :verified :

1.1. Loading line bypass valve “SDV-3112” shall be closed.Loading line bypass valve “SDV-3112” shall be closed.2.2. Slug Catcher inlet valve “SDV-3111” shall be open.Slug Catcher inlet valve “SDV-3111” shall be open.3.3. Station delivery line valve “SDV-3134” shall be closed.Station delivery line valve “SDV-3134” shall be closed.4.4. Discharge pipeline vent valve “BDV-3135” shall be closed.Discharge pipeline vent valve “BDV-3135” shall be closed.5.5. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be higher than set point. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be higher than set point. 6.6. The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be higher than set The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be higher than set

point.point.7.7. The fluid pressure “PIT-3123” within the Filter Separator shall be higher than set point.The fluid pressure “PIT-3123” within the Filter Separator shall be higher than set point.8.8. The fluid pressure “PIT-3133” at the station discharge shall be higher than set point.The fluid pressure “PIT-3133” at the station discharge shall be higher than set point.9.9. Vent_Monitoring_4 variable status shall be set.Vent_Monitoring_4 variable status shall be set.

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS The process sub-system can be in Starting state:The process sub-system can be in Starting state:

• STARTING: dynamic state whom leads to RUN state. STARTING: dynamic state whom leads to RUN state.

Following are showed the possible transitions:Following are showed the possible transitions:• STARTING dynamic state allows the transition from STOP PRESSURIZED to RUN. STARTING dynamic state allows the transition from STOP PRESSURIZED to RUN.

In order to update the SUB SYSTEM status to RUN status during the execution of STARTING procedure In order to update the SUB SYSTEM status to RUN status during the execution of STARTING procedure essentially the following conditions and actions shall be verified and followed through:essentially the following conditions and actions shall be verified and followed through:

1.1. Differential pressure across the station delivery line valve “SDV-3134” shall be lower than set Differential pressure across the station delivery line valve “SDV-3134” shall be lower than set point..point..

2.2. Station delivery line valve “SDV-3134” shall be open.Station delivery line valve “SDV-3134” shall be open.3.3. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be higher than set point. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be higher than set point. 4.4. The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be higher than set The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be higher than set

point.point.5.5. The fluid pressure “PIT-3123” within the Filter Separator shall be higher than set point.The fluid pressure “PIT-3123” within the Filter Separator shall be higher than set point.6.6. The fluid pressure “PIT-3133” at the station discharge shall be higher than set point.The fluid pressure “PIT-3133” at the station discharge shall be higher than set point.

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS The process sub-system can be in RUN state:The process sub-system can be in RUN state:

• RUN: operating functioning (compressors running and on load). RUN: operating functioning (compressors running and on load).

Following are showed the possible transitions:Following are showed the possible transitions:• RUN state can be achieved by completing the procedure of STARTING.RUN state can be achieved by completing the procedure of STARTING.

In order to maintain the RUN SUB SYSTEM status essentially the following conditions and actions shall be In order to maintain the RUN SUB SYSTEM status essentially the following conditions and actions shall be verified and followed through:verified and followed through:

1.1. Loading line bypass valve “SDV-3112” shall be closed.Loading line bypass valve “SDV-3112” shall be closed.2.2. Slug Catcher inlet valve “SDV-3111” shall be open.Slug Catcher inlet valve “SDV-3111” shall be open.3.3. Station delivery line valve “SDV-3134” shall be open.Station delivery line valve “SDV-3134” shall be open.4.4. Discharge pipeline vent valve “BDV-3135” shall be closed.Discharge pipeline vent valve “BDV-3135” shall be closed.5.5. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be above the set point. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be above the set point. 6.6. Vent_Monitoring_4 variable status shall be set.Vent_Monitoring_4 variable status shall be set.7.7. At least one compressor shall be in ON LOAD status.At least one compressor shall be in ON LOAD status.8.8. TRIGGER_x variable status shall be set if one compressor is operating in ON LOAD status.TRIGGER_x variable status shall be set if one compressor is operating in ON LOAD status.

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS The timer T141 is the maximum time that the main header system can operate in RUN status ( with The timer T141 is the maximum time that the main header system can operate in RUN status ( with station discharge valve opened ) without ON-LOAD turbines. If the timer T141 expires the main header station discharge valve opened ) without ON-LOAD turbines. If the timer T141 expires the main header status is forced to STOPPING immediately.status is forced to STOPPING immediately.

The flag named TRIGGER_y is set when the first turbine reach the On-load status; from this time, the The flag named TRIGGER_y is set when the first turbine reach the On-load status; from this time, the timer has no timer has no

effect, and if again no turbines is ON-LOAD, the main header status is forced to STOPPING immediately.effect, and if again no turbines is ON-LOAD, the main header status is forced to STOPPING immediately.

The flag TRIGGER_x shall be reset automatically if the state is not RUN or UNKNOWN.The flag TRIGGER_x shall be reset automatically if the state is not RUN or UNKNOWN.

This function is used to avoid the backflow of gas from the pipeline to the compression station through This function is used to avoid the backflow of gas from the pipeline to the compression station through the check the check

valve. valve.

To avoid the risk to close the station discharge valve “ SDV - 3134 “ while a turbine is ON-LOAD, if a To avoid the risk to close the station discharge valve “ SDV - 3134 “ while a turbine is ON-LOAD, if a turbine turbine

state is not defined (serial link in bad status) the trigger function is disabled.state is not defined (serial link in bad status) the trigger function is disabled.

MAIN HEADER SUBSYSTEMSMAIN HEADER SUBSYSTEMS The process sub-system can be in STOPPING state:The process sub-system can be in STOPPING state:

• STOPPING: dynamic state whom leads to STOP PRESSURIZED state. STOPPING: dynamic state whom leads to STOP PRESSURIZED state.

Following are showed the possible transitions:Following are showed the possible transitions:• STOPPING dynamic state allows the transition from RUN to STOP PRESSURIZED. STOPPING dynamic state allows the transition from RUN to STOP PRESSURIZED.

In order to update the SUB SYSTEM status to STOPPED PRESSURIZED status during the execution of STOPPING In order to update the SUB SYSTEM status to STOPPED PRESSURIZED status during the execution of STOPPING procedure essentially the following conditions and actions shall be verified and followed through:procedure essentially the following conditions and actions shall be verified and followed through:

1.1. Station delivery line valve “SDV-3134” shall be open.Station delivery line valve “SDV-3134” shall be open.

EMERGENCYEMERGENCY

If the ESD system force the SHUTDOWN of SDV-3111 or SDV-3112 or SDV-3134 or BDV-3135 the state If the ESD system force the SHUTDOWN of SDV-3111 or SDV-3112 or SDV-3134 or BDV-3135 the state variable of the variable of the Main Header sub-system Main Header sub-system that control the valves above mentioned and equipment that control the valves above mentioned and equipment shall be changed to UNKNOWN by means of the state RECOGNITION procedureshall be changed to UNKNOWN by means of the state RECOGNITION procedure . .


GLYCOL UTILITY SUBSYSTEMSGLYCOL UTILITY SUBSYSTEMS The process sub-system can be in Depressurization state:The process sub-system can be in Depressurization state:

• DEPRESSURIZATION: Dynamic state with delivery valve “ SDV – 3138 ” closed.DEPRESSURIZATION: Dynamic state with delivery valve “ SDV – 3138 ” closed.

Following are showed the possible transitions:Following are showed the possible transitions:• DEPRESSURIZATION dynamic state allows the transition from any state to DEPRESSURIZATION dynamic state allows the transition from any state to DEPRESSURIZED.DEPRESSURIZED.

In order to update the SUB SYSTEM status to DEPRESSURIZED status during the execution of In order to update the SUB SYSTEM status to DEPRESSURIZED status during the execution of DEPRESSURIZATION procedure essentially the following conditions and actions shall be verified and DEPRESSURIZATION procedure essentially the following conditions and actions shall be verified and followed through:followed through:

1.1. Glycol regeneration utility sub system inlet valve “SDV – 3138“ shall be closed.Glycol regeneration utility sub system inlet valve “SDV – 3138“ shall be closed.2.2. Process sub plant pressure “PIT-3138” shall be lower than set point.Process sub plant pressure “PIT-3138” shall be lower than set point.

GLYCOL UTILITY SUBSYSTEMSGLYCOL UTILITY SUBSYSTEMS The process sub-system can be in Pressurized state:The process sub-system can be in Pressurized state:

• DEPRESSURIZED: Static state with delivery valve “ SDV – 3138 “ closed (properly this state DEPRESSURIZED: Static state with delivery valve “ SDV – 3138 “ closed (properly this state certifies a NOT-PRESSURIZED process sub-system).certifies a NOT-PRESSURIZED process sub-system).



In order to maintain the DEPRESSURIZED SUB SYSTEM status essentially the following conditions shall In order to maintain the DEPRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified :be verified :

1.1. Glycol regeneration utility sub system inlet valve “SDV – 3138“ shall be closed.Glycol regeneration utility sub system inlet valve “SDV – 3138“ shall be closed.2.2. Process sub plant pressure “PIT-3138” shall be lower than set point.Process sub plant pressure “PIT-3138” shall be lower than set point.

GLYCOL UTILITY SUBSYSTEMSGLYCOL UTILITY SUBSYSTEMS The process sub-system can be in Depressurization state:The process sub-system can be in Depressurization state:

• PRESSURIZATION: Dynamic state with delivery valve “ SDV – 3138 “ opened.PRESSURIZATION: Dynamic state with delivery valve “ SDV – 3138 “ opened.

Following are showed the possible transitions:Following are showed the possible transitions:• PRESSURIZATION: Dynamic state which allows the transitions from DEPRESSURIZED to PRESSURIZATION: Dynamic state which allows the transitions from DEPRESSURIZED to PRESSURIZED.PRESSURIZED.

In order to update the SUB SYSTEM status to PRESSURIZED status during the execution of PRESSURIZATION In order to update the SUB SYSTEM status to PRESSURIZED status during the execution of PRESSURIZATION procedure essentially the following conditions and actions shall be verified and followed through:procedure essentially the following conditions and actions shall be verified and followed through:

1.1. Pipeline pressure “PIT-3134” shall be above the set point..Pipeline pressure “PIT-3134” shall be above the set point..2.2. Glycol regeneration utility sub system inlet valve “SDV – 3138“ shall be open.Glycol regeneration utility sub system inlet valve “SDV – 3138“ shall be open.3.3. Process sub plant pressure “PIT-3138” shall be higher than set point.Process sub plant pressure “PIT-3138” shall be higher than set point.4.4. Purging TIMEOUT shall be expired.Purging TIMEOUT shall be expired.

GLYCOL UTILITY SUBSYSTEMSGLYCOL UTILITY SUBSYSTEMS The process sub-system can be in Pressurized state:The process sub-system can be in Pressurized state:

• PRESSURIZED: Static state with delivery valve “ SDV – 3138 “ open.PRESSURIZED: Static state with delivery valve “ SDV – 3138 “ open.

Following are showed the possible transitions:Following are showed the possible transitions:• PRESSURIZED state can be achieved by completing the procedure of PRESSURIZATION. PRESSURIZED state can be achieved by completing the procedure of PRESSURIZATION.

In order to maintain the PRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified In order to maintain the PRESSURIZED SUB SYSTEM status essentially the following conditions shall be verified ::

1.1. Glycol regeneration utility sub system inlet valve “SDV – 3138“ shall be open.Glycol regeneration utility sub system inlet valve “SDV – 3138“ shall be open.2.2. Process sub plant pressure “PIT-3138” shall be higher than set point.Process sub plant pressure “PIT-3138” shall be higher than set point.

GLYCOL UTILITY SUBSYSTEMSGLYCOL UTILITY SUBSYSTEMS Operator can by-pass the gas dehydration system by operating the manual valves VBD10-3615, 3616, 3617.Operator can by-pass the gas dehydration system by operating the manual valves VBD10-3615, 3616, 3617. In this case the operator must insert a password into the ESD system.In this case the operator must insert a password into the ESD system. However this password shall not take effect on the glycol regeneration utility system.However this password shall not take effect on the glycol regeneration utility system.

EMERGENCYEMERGENCY

If the ESD system force the SHUTDOWN of SDV-3138 the state variable of the If the ESD system force the SHUTDOWN of SDV-3138 the state variable of the Glycol Utility sub-Glycol Utility sub-system system that control the valve above mentioned and equipment shall be changed to UNKNOWN by that control the valve above mentioned and equipment shall be changed to UNKNOWN by means of the state RECOGNITION proceduremeans of the state RECOGNITION procedure. .

GLYCOL UTILITY SUBSYSTEMSGLYCOL UTILITY SUBSYSTEMS

GLYCOL UTILITY SYSTEMGLYCOL UTILITY SYSTEM Gas forwarded though line 1”-A10-080-FG-12114 to the regeneration skid is used for two services:Gas forwarded though line 1”-A10-080-FG-12114 to the regeneration skid is used for two services:

1.1. as stripping gas for regeneration purpose;as stripping gas for regeneration purpose;

2.2. as blanketing in order to preserve glycol from atmosphere contamination.as blanketing in order to preserve glycol from atmosphere contamination.

When the gas flow is 0, the stripping gas is not necessary, but the gas for blanketing is still necessary.When the gas flow is 0, the stripping gas is not necessary, but the gas for blanketing is still necessary.

For this reason is considered not correct to close the SDV-3138 when the station flow is 0 and the gas out of our battery For this reason is considered not correct to close the SDV-3138 when the station flow is 0 and the gas out of our battery limit is cold. limit is cold.

In order to avoid that cold gas at high pressure is forwarded to regeneration skid, generating problem on PCV 3134/3135 it In order to avoid that cold gas at high pressure is forwarded to regeneration skid, generating problem on PCV 3134/3135 it is better to adopt the following procedure:is better to adopt the following procedure:

1.1. Close 1” valves 3826 and 3828 (SEE P&ID 7035-PH-0410). These valves are on the stripping gas line, if these valves Close 1” valves 3826 and 3828 (SEE P&ID 7035-PH-0410). These valves are on the stripping gas line, if these valves are closed the gas flow through SDV-3138 and PCV-3134/3135 is very low.are closed the gas flow through SDV-3138 and PCV-3134/3135 is very low.

2.2. Depressurize the part of pipe between discharge station valve SDV-3134 and SOCAR’s manual valve at 20 bar. Depressurize the part of pipe between discharge station valve SDV-3134 and SOCAR’s manual valve at 20 bar.

In this way the Differential Pressure across PCV3134/3135 is low and the possibility to damage the PCV is reduced.In this way the Differential Pressure across PCV3134/3135 is low and the possibility to damage the PCV is reduced.

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS The process sub-system can be in Cold Catch state:The process sub-system can be in Cold Catch state:

• COLD CATCH: Dynamic state after START command and STAND BY command disable. COLD CATCH: Dynamic state after START command and STAND BY command disable.

Following are showed the possible transitions:Following are showed the possible transitions:• COLD CATCH allows the transition from RUNNING state to READY state.COLD CATCH allows the transition from RUNNING state to READY state.

In order to update the SUB SYSTEM status to READY status during the execution of COLD CATCH procedure In order to update the SUB SYSTEM status to READY status during the execution of COLD CATCH procedure essentially the following conditions and actions shall be verified and followed through:essentially the following conditions and actions shall be verified and followed through:

1.1. DCS shall disables START command “XS-3610A” and Stand by command “XS-3610B” to PLC DCS shall disables START command “XS-3610A” and Stand by command “XS-3610B” to PLC Glycol Control System.Glycol Control System.

2.2. PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. 3.3. PLC Glycol Control System shall sends “READY TO START” signal “UL-3610A”PLC Glycol Control System shall sends “READY TO START” signal “UL-3610A” to DCS before to DCS before

TIMEOUT will expire.TIMEOUT will expire.

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS The process sub-system can be in Ready state:The process sub-system can be in Ready state:

• READY: Static state result of the fact that PLC whom controls the skid is ready to READY: Static state result of the fact that PLC whom controls the skid is ready to start. (Default state). start. (Default state).

Following are showed the possible transitions:Following are showed the possible transitions:• READY state is reachable after COLD CATCH procedure (or like default status).READY state is reachable after COLD CATCH procedure (or like default status).

In order to maintain the READY SUB SYSTEM status essentially the following conditions and actions In order to maintain the READY SUB SYSTEM status essentially the following conditions and actions shall be verified and followed through:shall be verified and followed through:

1.1. PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. 2.2. PLC Glycol Control System shall sends “READY TO START” signal “UL-3610A”PLC Glycol Control System shall sends “READY TO START” signal “UL-3610A” to DCS.to DCS.

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS PLC Glycol system sends the “ READY TO START ” PLC Glycol system sends the “ READY TO START ”

signal signal “ “UL-3610A” to DCS when the following conditions are UL-3610A” to DCS when the following conditions are

verified:verified:

• When SDV 3613B, SDV 3614B, SDV 3707 close PLC When SDV 3613B, SDV 3614B, SDV 3707 close PLC command is active, close limit switch feedback command is active, close limit switch feedback signal shall be reached in a predetermined time.signal shall be reached in a predetermined time.

• Emergency shut down from PLC shall not be Emergency shut down from PLC shall not be active. active.

• Shut down from ESD system “XSD-3610”Shut down from ESD system “XSD-3610” shall not shall not be be

active. active.

• The instrument air pressure “PSL 3713” shall be The instrument air pressure “PSL 3713” shall be inside a inside a

predetermined range.predetermined range. • The contactor glycol level “LSHH-3614B” shall be The contactor glycol level “LSHH-3614B” shall be

inside a inside a predetermined range.predetermined range.

• If one of the conditions above mentioned is not verified

a “ Glycol Dehydration Package Trip shall occurred”.

• The contactor glycol level “LSLL-3613B” shall be The contactor glycol level “LSLL-3613B” shall be inside a predetermined range.inside a predetermined range.

• The pressure outlet pump “PAHH-3714”The pressure outlet pump “PAHH-3714” shall be shall be inside a inside a

predetermined range. predetermined range.

• The Glycol Flush Drum pressure “PT 3717” & level The Glycol Flush Drum pressure “PT 3717” & level

“ “LAH 3705” & “LAH 3709” shall be inside a LAH 3705” & “LAH 3709” shall be inside a predetermined range. predetermined range.

• The glycol accumulator level “LALL 3713” shall be The glycol accumulator level “LALL 3713” shall be inside a inside a

predetermined range. predetermined range.

• When PLC Glycol control system sends start When PLC Glycol control system sends start “ “OBB-3710A/B” pumpOBB-3710A/B” pump command to MCC the “OBB-command to MCC the “OBB-

3710A” 3710A” glycol pump running feedback signal shall be glycol pump running feedback signal shall be

reached by reached by PLC Glycol Control system in a predetermined PLC Glycol Control system in a predetermined

time.time. “Alarm Glycol Pump “OBB-3710A” or OBB-3710B “OBB-3710A” or OBB-3710B

not occurred”.

• When PLC Glycol control system sends startWhen PLC Glycol control system sends start command to command to

MCC the ELECTRICAL HEATER running feedback MCC the ELECTRICAL HEATER running feedback signal signal

shall be reached in a predetermined time.shall be reached in a predetermined time. “Alarm Electrical Heater not occurred”.

• PLC shall not receives the ELECTRICAL HEATER PLC shall not receives the ELECTRICAL HEATER NOT NOT

READY signal from Electrical Heater.READY signal from Electrical Heater. (LSLL-3712; TSHH-3716; .. SEE FIGURE)(LSLL-3712; TSHH-3716; .. SEE FIGURE)

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS The process sub-system can be in Depressurization state:The process sub-system can be in Depressurization state:

• PREHEATING: Dynamic state after STAND BY command. PREHEATING: Dynamic state after STAND BY command.

Following are showed the possible transitions:Following are showed the possible transitions:• PREHEATING allows the transition from READY state to HOT state.PREHEATING allows the transition from READY state to HOT state.

In order to update the SUB SYSTEM status to HOT status during the execution of PREHEATING procedure In order to update the SUB SYSTEM status to HOT status during the execution of PREHEATING procedure essentially the following conditions and actions shall be verified and followed through:essentially the following conditions and actions shall be verified and followed through:

1.1. PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. 2.2. If Glycol regeneration utility sub system inlet pressure “PIT-3138” is not higher than a If Glycol regeneration utility sub system inlet pressure “PIT-3138” is not higher than a

predetermined set point a calling to “Cold Catch” procedure shall be carried out.predetermined set point a calling to “Cold Catch” procedure shall be carried out.3.3. If Contactor outlet pressure “PIT-3133” is not higher than a predetermined set pointIf Contactor outlet pressure “PIT-3133” is not higher than a predetermined set point a calling to a calling to

“Cold Catch” procedure shall be carried out.“Cold Catch” procedure shall be carried out.4.4. DCS shall sends “STAND BY” command “XS-3610B” to PLC Glycol Control System.DCS shall sends “STAND BY” command “XS-3610B” to PLC Glycol Control System.5.5. PLC Glycol Control System shall sends “HOT STATUS” signal “UL-3610B” to DCSPLC Glycol Control System shall sends “HOT STATUS” signal “UL-3610B” to DCS..

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS PLC Glycol system switch on the Electrical Heater when the following conditions are verified:PLC Glycol system switch on the Electrical Heater when the following conditions are verified:

• PLC PLC Glycol Control SystemGlycol Control System shall receives the STAND BY command “XS-3610B” shall receives the STAND BY command “XS-3610B” from DCS.from DCS.

• Electrical Heater shall sends Remote signal to PLC Glycol Control System. Electrical Heater shall sends Remote signal to PLC Glycol Control System.

• “Alarm Electrical Heater shall not occurred”.

• “ Glycol Dehydration Package Trip shall not occurred”.

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS The process sub-system can be in HOT state:The process sub-system can be in HOT state:

• HOT: Static state result of the fact that PLC whom controls the skid has completed the HOT: Static state result of the fact that PLC whom controls the skid has completed the preheating procedure. preheating procedure.

Following are showed the possible transitions:Following are showed the possible transitions:• HOT state is reachable after HOT CATCH from RUNNING state or after PREHEATING HOT state is reachable after HOT CATCH from RUNNING state or after PREHEATING

procedure from READY. procedure from READY.

In order to maintain the HOT SUB SYSTEM status essentially the following conditions and actions shall be In order to maintain the HOT SUB SYSTEM status essentially the following conditions and actions shall be verified and followed through :verified and followed through :

• PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. • If Glycol regeneration utility sub system inlet pressure “PIT-3138” is not higher than a If Glycol regeneration utility sub system inlet pressure “PIT-3138” is not higher than a

predetermined predetermined set point a calling to “Cold Catch” procedure shall be carried out.set point a calling to “Cold Catch” procedure shall be carried out.• If Contactor outlet pressure “PIT-3133” is higher than a predetermined set point a calling to If Contactor outlet pressure “PIT-3133” is higher than a predetermined set point a calling to

“Cold “Cold Catch” procedure shall be carried out.Catch” procedure shall be carried out.• PLC Glycol Control System shall sends “HOT STATUS” signal to DCS.PLC Glycol Control System shall sends “HOT STATUS” signal to DCS.

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS PLC Glycol system sends to DCS the HOT signal when the following conditions are verified:PLC Glycol system sends to DCS the HOT signal when the following conditions are verified:

• LIC 3613A & LIC 3706 level controller AUTO operating mode shall be set.LIC 3613A & LIC 3706 level controller AUTO operating mode shall be set.

• The pressure outlet pump “PAHH 3714” shall be inside a predetermined range. The pressure outlet pump “PAHH 3714” shall be inside a predetermined range.

• The Glycol Flush Drum pressure “PT 3717” & level “LAH 3705” shall be inside a The Glycol Flush Drum pressure “PT 3717” & level “LAH 3705” shall be inside a predetermined range. predetermined range.

• The glycol accumulator level “LALL 3713” shall be inside a predetermined range. The glycol accumulator level “LALL 3713” shall be inside a predetermined range.

• “ Alarm Glycol Pump “OBB-3710A”“OBB-3710A” or “OBB-3710B”“OBB-3710B” shall not occurred”.


• PLC shall receives the STAND BY command “XS-3610B” from DCS.PLC shall receives the STAND BY command “XS-3610B” from DCS.

• The Glycol Reboiler temperature “TT 3712” shall be inside a predetermined range.The Glycol Reboiler temperature “TT 3712” shall be inside a predetermined range.

• The contactor glycol level “LSHH 3613B” shall be inside a predetermined range.The contactor glycol level “LSHH 3613B” shall be inside a predetermined range.


• STARTING: Dynamic state after START command. STARTING: Dynamic state after START command.

Following are showed the possible transitions:Following are showed the possible transitions:• STARTING allows the transition from HOT state to RUNNING state.STARTING allows the transition from HOT state to RUNNING state.

In order to update the SUB SYSTEM status to RUNNING status during the execution of STARTING In order to update the SUB SYSTEM status to RUNNING status during the execution of STARTING procedure essentially the following conditions and actions shall be verified and followed through:procedure essentially the following conditions and actions shall be verified and followed through:


predetermined set point a calling to “Cold Catch” procedure shall be carried out.predetermined set point a calling to “Cold Catch” procedure shall be carried out.3.3. If Contactor outlet pressure “PIT-3133” If Contactor outlet pressure “PIT-3133” is not is not higher than a predetermined set point ahigher than a predetermined set point a a a

calling to “Cold Catch” procedure shall be carried out.calling to “Cold Catch” procedure shall be carried out. 4.4. Flow rate “FIT-3132” on Main Header System shall be available..Flow rate “FIT-3132” on Main Header System shall be available..5.5. DCS shall sends the START command “XS-3610A” to PLC Glycol Control System.DCS shall sends the START command “XS-3610A” to PLC Glycol Control System.6.6. PLC Glycol Control System shall sends “RUNNING” signal “UL-3610E”PLC Glycol Control System shall sends “RUNNING” signal “UL-3610E” to DCS.to DCS.

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS PLC Glycol Control System switch on the OBB-3710A or OBB-3710B glycol pump when the following PLC Glycol Control System switch on the OBB-3710A or OBB-3710B glycol pump when the following

conditions are conditions are verified:verified:

• PLC shall receives the START command “XS-3610A” from DCS.PLC shall receives the START command “XS-3610A” from DCS.

• The Glycol pump “OBB-3710A” or “OBB-3710B”The Glycol pump “OBB-3710A” or “OBB-3710B” shall be selected.shall be selected.

• The pressure outlet pump “PAHH 3714” shall be inside a predetermined range. The pressure outlet pump “PAHH 3714” shall be inside a predetermined range.

• The Glycol accumulator level “LALL 3713” shall be inside a predetermined range. The Glycol accumulator level “LALL 3713” shall be inside a predetermined range.

• The Glycol Reboiler temperature TT 3712” shall be inside a predetermined range.The Glycol Reboiler temperature TT 3712” shall be inside a predetermined range.

• The contactor Glycol level “LSHH 3613B” shall be inside a predetermined range.The contactor Glycol level “LSHH 3613B” shall be inside a predetermined range.

• “Alarm Glycol Pump “OBB-3710A”“OBB-3710A” or “OBB-3710B”“OBB-3710B” shall not occurred”.


GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS The process sub-system can be in Running state:The process sub-system can be in Running state:

• RUNNING: Static state result of the fact that PLC whom controls the skid is in running RUNNING: Static state result of the fact that PLC whom controls the skid is in running mode. mode.

Following are showed the possible transitions:Following are showed the possible transitions:• RUNNING state is reachable after STARTING procedure from HOT state. RUNNING state is reachable after STARTING procedure from HOT state.

In order to maintain the RUNNING SUB SYSTEM status essentially the following conditions shall be In order to maintain the RUNNING SUB SYSTEM status essentially the following conditions shall be verified :verified :


predetermined set pointpredetermined set point a calling to “Cold Catch” procedure shall be carried out.a calling to “Cold Catch” procedure shall be carried out.3.3. If Contactor outlet pressure “PIT-3133” is not higher than a predetermined set pointIf Contactor outlet pressure “PIT-3133” is not higher than a predetermined set point a a

calling to “Cold Catch” procedure shall be carried out.calling to “Cold Catch” procedure shall be carried out. 4.4. If a flow rate “FIT-3132” is not available on Main Header System a calling to “Hot Catch” If a flow rate “FIT-3132” is not available on Main Header System a calling to “Hot Catch”

procedure shall be carried out.procedure shall be carried out.5.5. PLC Glycol Control System shall sends “RUNNING” signal “UL-3610E”PLC Glycol Control System shall sends “RUNNING” signal “UL-3610E” to DCS.to DCS.

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS PLC Glycol system sends RUNNING signal “UL-3610A“ to DCS when the following conditions are verified:PLC Glycol system sends RUNNING signal “UL-3610A“ to DCS when the following conditions are verified:

• PLC Glycol Control System shall receives the START command “XS-3610A“ from DCS.PLC Glycol Control System shall receives the START command “XS-3610A“ from DCS.

• At least one Glycol Pump “OBB-3710A”“OBB-3710A” or “OBB-3710B”“OBB-3710B” shall be running.


• HOT CATCH: Dynamic state after START command disable (STOP). HOT CATCH: Dynamic state after START command disable (STOP).

Following are showed the possible transitions:Following are showed the possible transitions:• HOT CATCH allows the transition from RUNNING state to HOT state. HOT CATCH allows the transition from RUNNING state to HOT state.

In order to update the SUB SYSTEM status to HOT status during the execution of HOT CATH procedure In order to update the SUB SYSTEM status to HOT status during the execution of HOT CATH procedure essentially the following conditions and actions shall be verified and followed through:essentially the following conditions and actions shall be verified and followed through:

1.1. DCS shall disables START command “XS-3610A” to PLC Glycol Control System.DCS shall disables START command “XS-3610A” to PLC Glycol Control System.2.2. PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. PLC Glycol Control System shall sends REMOTE signal “UL-3610D” to DCS. 3.3. If Glycol regeneration utility sub system inlet pressure “PIT-3138” is not higher than a If Glycol regeneration utility sub system inlet pressure “PIT-3138” is not higher than a 4.4. predetermined set point a calling to “Cold Catch” procedure shall be carried out.predetermined set point a calling to “Cold Catch” procedure shall be carried out.5.5. If Contactor outlet pressure “PIT-3133” is not higher than a predetermined set pointIf Contactor outlet pressure “PIT-3133” is not higher than a predetermined set point a a

calling to “Cold Catch” procedure shall be carried out.calling to “Cold Catch” procedure shall be carried out. 6.6. Glycol Control System shall sends “HOT STATUS” signal “UL-3610B”Glycol Control System shall sends “HOT STATUS” signal “UL-3610B” to DCS.to DCS.

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMSEMERGENCYEMERGENCY

When Glycol regeneration skid shutdown When Glycol regeneration skid shutdown XSD-3610XSD-3610 signal is forced the state variable of the signal is forced the state variable of the Glycol Reg. sub-system Glycol Reg. sub-system shall be changed to UNKNOWN by means of the state shall be changed to UNKNOWN by means of the state RECOGNITION procedure.RECOGNITION procedure.

GLYCOL SYSTEM CONTROLLERSGLYCOL SYSTEM CONTROLLERS PLC Glycol control system enables the Temperature controller “TIC-3712”PLC Glycol control system enables the Temperature controller “TIC-3712” set point of 0 C when at set point of 0 C when at

least one of the least one of the following conditions is verified:following conditions is verified:

• Heater Control Panel shall not send REMOTE signal “UL-3710C” to PLC Glycol Control System.Heater Control Panel shall not send REMOTE signal “UL-3710C” to PLC Glycol Control System.

• DCS shall not sends START command “XS-3610A” to PLC Glycol Control System & PLC Glycol DCS shall not sends START command “XS-3610A” to PLC Glycol Control System & PLC Glycol Control System Control System

shall not sends START command to Heater Control Panel.shall not sends START command to Heater Control Panel.

• Shut down from ESD system shall not be active.Shut down from ESD system shall not be active.

PLC Glycol control system enables the Temperature controller “TIC-3712”PLC Glycol control system enables the Temperature controller “TIC-3712” set point of 80 C when the set point of 80 C when the following following

conditions are verified:conditions are verified:

1.1. DCS shall not sends START command “XS-3610A” to PLC Glycol Control System & PLC Glycol DCS shall not sends START command “XS-3610A” to PLC Glycol Control System & PLC Glycol Control System Control System

shall sends START command to Heater Control Panel.shall sends START command to Heater Control Panel.

PLC Glycol control system enables the Temperature controller “TIC-3712”PLC Glycol control system enables the Temperature controller “TIC-3712” set point of 200 C when the set point of 200 C when the following following

conditions are verified:conditions are verified:

1.1. DCS shall sends START command “XS-3610A” to PLC Glycol Control System & PLC Glycol DCS shall sends START command “XS-3610A” to PLC Glycol Control System & PLC Glycol Control System Control System

shall sends START command to Heater Control Panel.shall sends START command to Heater Control Panel.

GLYCOL SYSTEM CONTROLLERSGLYCOL SYSTEM CONTROLLERS Temperature controller “TIC-3710” AUTO operating mode is enabled when the following conditions are Temperature controller “TIC-3710” AUTO operating mode is enabled when the following conditions are

verified: verified:

1.1. DCS shall sends START command “XS-3610A” to PLC Glycol Control System.DCS shall sends START command “XS-3610A” to PLC Glycol Control System.

GLYCOL SYSTEM CONTROLLERSGLYCOL SYSTEM CONTROLLERS Level controller “LIC 3706” AUTO operating mode is enabled when the following conditions are verified:Level controller “LIC 3706” AUTO operating mode is enabled when the following conditions are verified:

1.1. DCS shall sends STAND BY command “XS-3610B”DCS shall sends STAND BY command “XS-3610B” to PLC Glycol Control System. to PLC Glycol Control System.

2.2. The contactor glycol level “LALL 3708” shall be higher than set point. The contactor glycol level “LALL 3708” shall be higher than set point.

3.3. The Glycol Flush Drum pressure “PT 3717” shall be higher than set point.The Glycol Flush Drum pressure “PT 3717” shall be higher than set point.

GLYCOL SYSTEM CONTROLLERSGLYCOL SYSTEM CONTROLLERS Flow controller “FIC 3700” AUTO operating mode is enabled when the following conditions are Flow controller “FIC 3700” AUTO operating mode is enabled when the following conditions are

verifiedverified:

• DCS shall sends START command “XS-3610A” to PLC Glycol Control System.DCS shall sends START command “XS-3610A” to PLC Glycol Control System.

If the pump “OBB-3710A” is running, the changeover to pump “OBB-3710B” is performed when the If the pump “OBB-3710A” is running, the changeover to pump “OBB-3710B” is performed when the following conditions are verified:following conditions are verified:

• The pump “OBB-3710A” shall be selected.The pump “OBB-3710A” shall be selected.

• “Alarm Glycol Pump “OBB-3710A”“OBB-3710A” shall occurred”.

GLYCOL SYSTEM CONTROLLERSGLYCOL SYSTEM CONTROLLERS Level controller “LIC 3613A” AUTO operating mode is enabled when the following conditions are verified:Level controller “LIC 3613A” AUTO operating mode is enabled when the following conditions are verified:

1.1. DCS shall sends STAND BY command “XS-3610B”DCS shall sends STAND BY command “XS-3610B” to PLC Glycol Control System. to PLC Glycol Control System.

2.2. The contactor glycol level “LSLL 3613B” shall be higher than set point. The contactor glycol level “LSLL 3613B” shall be higher than set point.

3.3. The Glycol Flush Drum level “LAH 3709” shall be lower than set point.The Glycol Flush Drum level “LAH 3709” shall be lower than set point.

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS The process sub-system can be in STOPPING state:The process sub-system can be in STOPPING state:

• STOPPING Dynamic state which leads to READY state.STOPPING Dynamic state which leads to READY state.

Following are showed the possible transitions:Following are showed the possible transitions:• STOPPING is a dynamic state that allows the transition from any state to READY state.STOPPING is a dynamic state that allows the transition from any state to READY state.

In order to update the SUB SYSTEM status to READY during the execution of STOPPING procedure essentially the following conditions & actions shall be verified and followed through:

1.1. DCS shall forces the STOP command “ XS – 3X44 ” to UCP turbine control system.DCS shall forces the STOP command “ XS – 3X44 ” to UCP turbine control system.2. Turbine Cool down shall be initiated and UCP control system shall sends the Cool down signal

to DCS.3. Turbine speed shall be lower than set point.4. DCS shall removes STOP command to UCP control system and cooler stopping timer shall be

started up.5. N cooler motors shall not be fault.6. UCP turbine control system shall sends the “ READY TO RUN “ signal to DCS.

STOPPINGSTOPPING

TRUETRUE

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS The process sub-system can be in Ready state:The process sub-system can be in Ready state:

• READY: Static state with turbine stopped and ready to start.READY: Static state with turbine stopped and ready to start.

Following are showed the possible transitions:Following are showed the possible transitions:• READY state is reachable after STOPPING procedure.READY state is reachable after STOPPING procedure.

In order to maintain the READY SUB-SYSTEM status essentially the following conditions shall be verified & actions shall be verified and followed through:

1.1. At least N cooler motors shall not be faultAt least N cooler motors shall not be fault2.2. Turbine actual speed shall be lower than set point.Turbine actual speed shall be lower than set point.3. UCP turbine control system shall sends the “ READY TO RUN “ signal to DCS.

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS The process sub-system can be in STARTING state:The process sub-system can be in STARTING state:

• STARTING: Dynamic state which leads to IDLE state from READY state.STARTING: Dynamic state which leads to IDLE state from READY state.

Following are showed the possible transitions:Following are showed the possible transitions:• STARTING is a dynamic state that allows the transition from READY state to IDLE state. STARTING is a dynamic state that allows the transition from READY state to IDLE state.

In order to update the SUB SYSTEM status to IDLE during the execution of STARTING procedure essentially the following conditions & actions shall be verified and followed through;

1.1. The variable HAW_STARTThe variable HAW_START status shall be checked and updates to ON status if it is in OFF status.

2. Cooler motors starting shall be carried out sequentially and at the end of this phase the the variable variable HAW_START shall be reset to off status.HAW_START shall be reset to off status.

3.3. HP Turbines: Main Header HP suction pressure shall be higher than set point.HP Turbines: Main Header HP suction pressure shall be higher than set point.4. DCS shall selects NGP control (Manual) and sends remote speed set point to UCP turbine

control system.5. DCS shall sends START command “ XS – 3X40 “ to UCP turbines control system.6. UCP turbine control system shall sends the “ READY TO LOAD “ signal to DCS.

STARTINGSTARTING

The turbine control from DCS is possible only if the serial link connection working rightly. The turbine control from DCS is possible only if the serial link connection working rightly.

The turbine commands from DCS to the turbine are enabled only if the turbine CONTROL MODE from UCP is in The turbine commands from DCS to the turbine are enabled only if the turbine CONTROL MODE from UCP is in REMOTE. REMOTE.

In this case, if the sub-system is in SEMI-AUTOMATIC, the turbine status is controlled by using the NGP or suction In this case, if the sub-system is in SEMI-AUTOMATIC, the turbine status is controlled by using the NGP or suction pressure pressure

set point control mode. set point control mode.

To pilot the Turbine in IDLE state, the control is set to MANUAL (NGP) with a set-point of 80%, while to pilot the LP To pilot the Turbine in IDLE state, the control is set to MANUAL (NGP) with a set-point of 80%, while to pilot the LP Turbine Turbine

in ON-Load state the control is set to AUTO (suction pressure) with a set-point of 445 kPa ( 1600 Kpa for HP Unit ). in ON-Load state the control is set to AUTO (suction pressure) with a set-point of 445 kPa ( 1600 Kpa for HP Unit ).

For this reason, in SEMI-AUTOMATIC mode, the set-point are locked and the operator can not change it.For this reason, in SEMI-AUTOMATIC mode, the set-point are locked and the operator can not change it.

If the sub-system is in MANUAL, the turbine state can be change by operator from DCS changing the NGP or If the sub-system is in MANUAL, the turbine state can be change by operator from DCS changing the NGP or PRESSURE PRESSURE

set point values. set point values.

If the CONTROL MODE from UCP is in LOCAL or AUX no command are possible to the operator from DCS with the If the CONTROL MODE from UCP is in LOCAL or AUX no command are possible to the operator from DCS with the exception exception

of the STOP. of the STOP.

Whichever control mode is used, the automatic state recognize procedure is active to identify the turbine status.Whichever control mode is used, the automatic state recognize procedure is active to identify the turbine status.

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS To avoid an overload on the electrical system caused by inrush current, the motors of each cooler are To avoid an overload on the electrical system caused by inrush current, the motors of each cooler are

started at started at different time sequentially.different time sequentially. Furthermore, the variable HAW_START is used to postpone the coolers motors starting, if another Furthermore, the variable HAW_START is used to postpone the coolers motors starting, if another

cooler is in the starting phase. cooler is in the starting phase. If the starting phase is interrupted in asynchronous mode the variable shall be reset.If the starting phase is interrupted in asynchronous mode the variable shall be reset. The variable HAW_START is a common parameter for all the turbine logic sequence.The variable HAW_START is a common parameter for all the turbine logic sequence. The coolers motor could be started/stopped manually by the operator also if the sub-system is in Semi-The coolers motor could be started/stopped manually by the operator also if the sub-system is in Semi-

auto mode.auto mode. The The cooler motors motors status is maintained when the operation mode is switched from Semi-auto to

manual and vice-versa. The automatic cooler starting sequence is executed:

• When the operation mode is semi-automatic and the automatic state recognize procedure, identify a new state that require gas cooling (on-load or idle states) and sub system goes from UNLNOWN state to STAND-BY or

ON LOAD state by executing the Cooler procedure.• During STARTING dynamic phase; • During PWR-OFF phase at power recovery.

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS When all cooler motors are switched off the “TIC-3X33” controller AUTO or CASCATE When all cooler motors are switched off the “TIC-3X33” controller AUTO or CASCATE

operating mode shall be disabled and the TIC controller MANUAL operating mode shall operating mode shall be disabled and the TIC controller MANUAL operating mode shall be enable.be enable.

In Manual MODE the operator can change the controller output.In Manual MODE the operator can change the controller output. In AUTO mode the operator can changes the controller set point in a predetermined In AUTO mode the operator can changes the controller set point in a predetermined

range. range. In CASCATE operating mode the set point is fixed. In CASCATE operating mode the set point is fixed.

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS The process sub-system can be in IDLE state:The process sub-system can be in IDLE state:

• IDLE: The unit is operating at idle set point speed (typical: 50-60% NPT or 72-78% IDLE: The unit is operating at idle set point speed (typical: 50-60% NPT or 72-78% NGP).NGP).

Following are showed the possible transitions:Following are showed the possible transitions:• IDLE state is reachable after STARTING procedure from READY state or after IDLE state is reachable after STARTING procedure from READY state or after

UNLOADING UNLOADING procedure from ON-LOAD state.procedure from ON-LOAD state.• IDLE state is also reachable after an electrical fault with PWR-OFF procedure.IDLE state is also reachable after an electrical fault with PWR-OFF procedure.

In order to maintain the IDLE SUB-SYSTEM status essentially the following conditions shall be verified & actions shall be verified and followed through:

1.1. The minimum of N cooler motors shall be running.The minimum of N cooler motors shall be running.2. UCP turbine control system shall sends the “ READY TO LOAD “ signal to DCS.

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS The process sub-system can be in LOADING state:The process sub-system can be in LOADING state:

• LOADING: Dynamic state which leads to ON-LOAD state.LOADING: Dynamic state which leads to ON-LOAD state.

Following are showed the possible transitions:Following are showed the possible transitions:• LOADING is a dynamic state that allows the transition from IDLE state to ON-LOAD LOADING is a dynamic state that allows the transition from IDLE state to ON-LOAD

state.state.

In order to update the SUB SYSTEM status to ON LOAD during the execution of LOADING procedure essentially the following conditions & actions shall be verified and followed through:

1.1. UCP turbine control system UCP turbine control system shall sends CONTROL REMOTE signal to DCS.2.2. Station discharge valve SDV 3134 shall be open..Station discharge valve SDV 3134 shall be open..3.3. HP Turbines: At least one LP turbine shall be in ON LOAD status..HP Turbines: At least one LP turbine shall be in ON LOAD status..4.4. DCS shall selects suction pressure control (AUTO) and sends to UCP turbine control DCS shall selects suction pressure control (AUTO) and sends to UCP turbine control

system suction pressure set point command. system suction pressure set point command. 5. UCP turbine control system shall sends the “ ON LOAD “ signal to DCS.

LOADINGLOADING

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS The process sub-system can be in ON-LOAD state:The process sub-system can be in ON-LOAD state:

• ON-LOAD: The unit is operating at suction pressure set point. ON-LOAD: The unit is operating at suction pressure set point.

Following are showed the possible transitions:Following are showed the possible transitions:• ON-LOAD state is reachable after LOADING procedure from IDLE state. ON-LOAD state is reachable after LOADING procedure from IDLE state.

In order to maintain the IDLE SUB-SYSTEM status essentially the following conditions shall be verified & actions shall be verified and followed through:

1.1. The minimum of N cooler motors shall be running.The minimum of N cooler motors shall be running.2.2. HP Turbines: At least one LP turbine shall be in ON LOAD status.HP Turbines: At least one LP turbine shall be in ON LOAD status.3. UCP turbine control system shall sends the “ ON LOAD “ signal to DCS.

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS The process sub-system can be in UNLOADING state:The process sub-system can be in UNLOADING state:

• UNLOADING: Dynamic state which leads to IDLE state from ON-LOAD state. UNLOADING: Dynamic state which leads to IDLE state from ON-LOAD state.

Following are showed the possible transitions:Following are showed the possible transitions:• UNLOADING is a dynamic state that allows the transition from ON-LOAD state to UNLOADING is a dynamic state that allows the transition from ON-LOAD state to

IDLE state.IDLE state.

In order to update the SUB SYSTEM status to IDLE during the execution of UNLOADING procedure essentially the following conditions & actions shall be verified and followed through;

1.1. DCS shall selects NGP control (MANUAL) and it shall sends remote speed set point to DCS shall selects NGP control (MANUAL) and it shall sends remote speed set point to UCP turbine control system.UCP turbine control system.

2. UCP turbine control system shall sends the “ READY TO LOAD “ signal to DCS.

UNLOADINGUNLOADING

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS The process sub-system can be in Power Off state:The process sub-system can be in Power Off state:

• PWR-OFF: Dynamic state that, if the turbine was running, leads to IDLE state in case of electrical PWR-OFF: Dynamic state that, if the turbine was running, leads to IDLE state in case of electrical fault. fault.

Following are showed the possible transitions:Following are showed the possible transitions:• PWR-OFF is a dynamic state that allows the transition from any state to static state IDLE or READY PWR-OFF is a dynamic state that allows the transition from any state to static state IDLE or READY state by calling the STOPPING procedure.state by calling the STOPPING procedure.• This transition is called automatically when a power failure is detected and shall not available in This transition is called automatically when a power failure is detected and shall not available in

manual manual mode.mode.

During the execution of PWR-OFFPWR-OFF procedure essentially the following conditions & actions shall be verified and followed through:

• DCS shall performs the Cooler motors stopping sequentially DCS shall performs the Cooler motors stopping sequentially by forcing the variable HAW_START to the forcing the variable HAW_START to the off state off state

and shall forces STOP command “XS – 3244”and shall forces STOP command “XS – 3244” to UCP turbine Control system.• DCS shall selects NGP control (MANUAL) and it shall sends remote speed set point to UCP turbine DCS shall selects NGP control (MANUAL) and it shall sends remote speed set point to UCP turbine

control system.control system.• When electrical power supply change back normal if Compressor speed is lower than set point, serial When electrical power supply change back normal if Compressor speed is lower than set point, serial

link status is good and Stopping Cooler timer is expired the stopping procedure is called and started link status is good and Stopping Cooler timer is expired the stopping procedure is called and started up otherwise the following up otherwise the following

conditions conditions & actions shall be verified and followed through:1.1. DCS shall performs the Cooler motors starting sequentially DCS shall performs the Cooler motors starting sequentially by forcing the variable HAW_START to forcing the variable HAW_START to

ON state.ON state.2.2. The minimum of “N” cooler motors shall be running.The minimum of “N” cooler motors shall be running.3.3. DCS shall removes Stop command to PLC and reset from UCP shall be achieved.DCS shall removes Stop command to PLC and reset from UCP shall be achieved.

POWER OFFPOWER OFF

The COOLDOWN FORCING operation is an always run procedure which is active even if the system is in manual mode The COOLDOWN FORCING operation is an always run procedure which is active even if the system is in manual mode and guarantees the and guarantees the

safety operation of compressor by the checking of vital process parameters of the system. safety operation of compressor by the checking of vital process parameters of the system. The normal stop forcing is removed only when the cause is disappeared.The normal stop forcing is removed only when the cause is disappeared.

A local CD_X variableA local CD_X variable is used to force the Stop command “XS – 3X44”is used to force the Stop command “XS – 3X44” to the OFF state and to release it at the end of to the OFF state and to release it at the end of the alarm. the alarm.

During the execution of COOLDOWN FORCING procedure if one of the following conditions are not verified the stopping During the execution of COOLDOWN FORCING procedure if one of the following conditions are not verified the stopping procedure is procedure is

called and started up, called and started up, DCS shall forces STOP command “ XS – 3X44 ”DCS shall forces STOP command “ XS – 3X44 ” to PLC , sets the local CD_X variable to the OFF state and to PLC , sets the local CD_X variable to the OFF state and the Cool down of the unit shall initiate.the Cool down of the unit shall initiate.

• Main Header vent valve BDV - 3135 shall be closed.Main Header vent valve BDV - 3135 shall be closed.• Main Header subsystem shall be purged. (Vent_Monitoring_4 <> 0).Main Header subsystem shall be purged. (Vent_Monitoring_4 <> 0).• Seal Gas Pressure PIT – 3X53 shall be higher than a predetermined setpoint.Seal Gas Pressure PIT – 3X53 shall be higher than a predetermined setpoint.• Delta pressure across the inlet turbine valve “ SDV – 3X14 “ shall be below the max pressure value allowable.Delta pressure across the inlet turbine valve “ SDV – 3X14 “ shall be below the max pressure value allowable.• Main Header station discharge valve “ SDV -3134 “ shall be open.Main Header station discharge valve “ SDV -3134 “ shall be open.

If the condition above mentioned are verified and Compressor speed is lower than set point or Main Header station If the condition above mentioned are verified and Compressor speed is lower than set point or Main Header station discharge valve discharge valve

SDV – 3134 is open DCS shall removes the Stop command “ XS – 3X44 “ to PLC and sets the local CD_X variable to the ON SDV – 3134 is open DCS shall removes the Stop command “ XS – 3X44 “ to PLC and sets the local CD_X variable to the ON state. state.

The Cool down stop leads the unit to the IDLE state and, at the end of a UCP timer, to the STOP PRESSURIZED state.The Cool down stop leads the unit to the IDLE state and, at the end of a UCP timer, to the STOP PRESSURIZED state.

If one of conditions, above mentioned and highlighted in red, is not verified a depressurization of the unit is also If one of conditions, above mentioned and highlighted in red, is not verified a depressurization of the unit is also necessary, and the necessary, and the

FAST_STOP_DEPRESS procedure generates through the ESD system the Fast Stop depressurized command “XSD – 3X42 ” FAST_STOP_DEPRESS procedure generates through the ESD system the Fast Stop depressurized command “XSD – 3X42 ” to the UCP to the UCP

turbine unit.turbine unit.

TURBINE LP A,B – HP A,B SUBSYSTEMSTURBINE LP A,B – HP A,B SUBSYSTEMS

AUTOMATIC: (BASIC USER)AUTOMATIC: (BASIC USER) In automatic mode a series of macro procedures are available which recall the sub sequences of

the sub systems, allowing to operator to perform complex tasks.

The automatic macro procedures are available only if the related sub systems status involved is not equal to UNKNOWN state.

The automatic macro procedures are mutually exclusive.

MACROPROCEDUREMACROPROCEDURE A Macroprocedure is A Macroprocedure is a sort of "main program“.

It is a Macrosequence, which executes simultaneously several sequence of several SUB SYSTEMS in Macrosequence, which executes simultaneously several sequence of several SUB SYSTEMS in order to lead the entire plant or a part of it in a defined state.order to lead the entire plant or a part of it in a defined state.

MACROPROCEDURE EXECUTION TABLEMACROPROCEDURE EXECUTION TABLE

Notes for Macroprocedures execution:Notes for Macroprocedures execution:

In correspondence to each row are mentioned all conditions shall be verified to activate the single In correspondence to each row are mentioned all conditions shall be verified to activate the single Macroprocedure.Macroprocedure.

In correspondence to each column are indicated which Macroprocedure could be active (Y) at whatever time and In correspondence to each column are indicated which Macroprocedure could be active (Y) at whatever time and which which

Macroprocedure must be not active (N), ( the related push button is not active ) in order to start up the single Macroprocedure must be not active (N), ( the related push button is not active ) in order to start up the single Macroprocedure inMacroprocedure in

correspondence to the row.correspondence to the row.

Y: The Macroprocedure in correspondence to the row shall be available also if the related "Allowable States at the Y: The Macroprocedure in correspondence to the row shall be available also if the related "Allowable States at the beginning"beginning" are are

verifiedverified.

Y (INT): If the Macroprocedure in correspondence to the row is started the active one in correspondence to the Y (INT): If the Macroprocedure in correspondence to the row is started the active one in correspondence to the column shall be column shall be

interrupted.interrupted.

(1): If the Macroprocedure in correspondence to the row is started the active one in correspondence to the (1): If the Macroprocedure in correspondence to the row is started the active one in correspondence to the column could be interrupted by itself. column could be interrupted by itself.

(2): These condition is not really possible.(2): These condition is not really possible.

When the single Macroprocedure is active the Macroprocedure actives automatically the buttons showed within the When the single Macroprocedure is active the Macroprocedure actives automatically the buttons showed within the sequence sequence

management DCS graphic page of the subsystems involved and it executes automatically the commands to carried management DCS graphic page of the subsystems involved and it executes automatically the commands to carried out the transitions out the transitions

between the static states.between the static states.

MACROPROCEDUREMACROPROCEDURE

General Notes :General Notes :

A macroprocedure is available if the "allowable state at the beginning" at “ time 0 ” are checked and A macroprocedure is available if the "allowable state at the beginning" at “ time 0 ” are checked and verified in verified in

according to the multiple macroprocedure execution table. according to the multiple macroprocedure execution table.

The macroprocedures is activated by a push button (START SEQUENCE)The macroprocedures is activated by a push button (START SEQUENCE) that will be released at that will be released at end of macroprocedure or by the operator exit forcing.end of macroprocedure or by the operator exit forcing.

If a macroprocedures are not available the related push button (START, STOP SEQUENCE) shall be inactive. If a macroprocedures are not available the related push button (START, STOP SEQUENCE) shall be inactive.

It shall be possible for the operator to exit from a macroprocedure at any time ( STOP SEQUENCE).It shall be possible for the operator to exit from a macroprocedure at any time ( STOP SEQUENCE).


Notes for Macroprocedures execution:Notes for Macroprocedures execution:

According to the multiple Macroprocedure execution table if a cell, in correspondence to the According to the multiple Macroprocedure execution table if a cell, in correspondence to the even TIMEn even TIMEn

column, contains more than one state (dynamic and/or static), the verification on the allowable column, contains more than one state (dynamic and/or static), the verification on the allowable states is states is

carried out positively if the actual sub system state dovetails to one of the states indicated carried out positively if the actual sub system state dovetails to one of the states indicated within the cell.within the cell.

According to the multiple Macroprocedure execution tableAccording to the multiple Macroprocedure execution table a dynamic procedure, in a dynamic procedure, in correspondence to the odd correspondence to the odd

TIMEnTIMEn column, column, shall be called only if the condition inside bracket (if any) is verified and it shall shall be called only if the condition inside bracket (if any) is verified and it shall be runningbe running

until the next TIME conditions are checked in according to Macroprocedure the flow chart.until the next TIME conditions are checked in according to Macroprocedure the flow chart.


MACROPROCEDURE: HEADER PRESSURIZATIONMACROPROCEDURE: HEADER PRESSURIZATION

MACROPROCEDURE: DEHYDRATION SYSTEM PUMP STOP MACROPROCEDURE: DEHYDRATION SYSTEM PUMP STOP

MACROPROCEDURE: DEHYDRATION SYSTEM HEATER STOPMACROPROCEDURE: DEHYDRATION SYSTEM HEATER STOP

MACROPROCEDURE:TURBINE MACROPROCEDURE:TURBINE LP A,B - HP A,B LP A,B - HP A,B UNLOADUNLOAD

MACROPROCEDURE:TURBINE MACROPROCEDURE:TURBINE LP A,B – HP A,B LP A,B – HP A,B STOPSTOP

Notes for Macroprocedure execution:Notes for Macroprocedure execution:

If the Modbus link does not work (Bad condition) the signal "HPC Actual speed" is not If the Modbus link does not work (Bad condition) the signal "HPC Actual speed" is not checked.checked.

MACROPROCEDURE FLOW CHARTMACROPROCEDURE FLOW CHART

MACROPROCEDURE: DEHYDRATION SYSTEM STARTMACROPROCEDURE: DEHYDRATION SYSTEM START

MACROPROCEDURE: DEPRESSURIZATIONMACROPROCEDURE: DEPRESSURIZATION Notes for Macroprocedure execution:Notes for Macroprocedure execution:

If the Modbus link doesn't work (Bad condition) the signal "ST-Case-Depressurized" is not checked.If the Modbus link doesn't work (Bad condition) the signal "ST-Case-Depressurized" is not checked.

MACROPROCEDURE:MACROPROCEDURE:DEPRESSURIZATION DEPRESSURIZATION TURBINE A,B-LP, A,B-HP (UTILITY GAS)TURBINE A,B-LP, A,B-HP (UTILITY GAS)

Notes for Macroprocedure execution:Notes for Macroprocedure execution:

The compressor shall be depressurized to allow seal gas depressurization (The compressor shall be depressurized to allow seal gas depressurization ("ST-Case-"ST-Case-Pressurized"Pressurized" shall

be in off status.

(2) if the Modbus link does not work (Bad condition) the signal "ST-Case-Pressurized" is not (2) if the Modbus link does not work (Bad condition) the signal "ST-Case-Pressurized" is not checked.checked.

andand

MACROPROCEDURE: DEHYDRATION SYSTEM PREHEATMACROPROCEDURE: DEHYDRATION SYSTEM PREHEAT

and bypass is not active )and bypass is not active )

MACROPROCEDURE:TURBINE LP A,B -STARTMACROPROCEDURE:TURBINE LP A,B -START

MACROPROCEDURE:TURBINE LPA,B - LOADMACROPROCEDURE:TURBINE LPA,B - LOAD

MACROPROCEDURE:TURBINE HP A,B - STARTMACROPROCEDURE:TURBINE HP A,B - START

MACROPROCEDURE:TURBINE HP A,B - LOADMACROPROCEDURE:TURBINE HP A,B - LOAD Notes for Macroprocedure execution:Notes for Macroprocedure execution:

1.1. At least one of the LP turbines shall be in ON-LOAD state.At least one of the LP turbines shall be in ON-LOAD state.

Manual: (Professional User)Manual: (Professional User) The manual mode allows the lowest level, but also the most powerful and flexible, interaction with the plant.

It is "critical“ operating mode to avoid although the plant potentially dangerous manoeuvre are not allowed by the system (the procedures that manage the security of the system are always run).

The manual mode allows the operator to intervene "almost" in every part of the plant, with the only limitations imposed by the procedures of "always running".

In Manual operating mode Static procedure of involved sub systems are executed by DCS system. In Manual operating mode Static procedure of involved sub systems are executed by DCS system.

During the execution of Static Procedure conditions are continuously checked up by DCS Control system.During the execution of Static Procedure conditions are continuously checked up by DCS Control system.

Close and Open valves commands are enabled on valves faceplate if the relative subsystem is in Manual Close and Open valves commands are enabled on valves faceplate if the relative subsystem is in Manual operating mode and “CASCATE” or “AUTO” valves operating mode on faceplate can be active by the operating mode and “CASCATE” or “AUTO” valves operating mode on faceplate can be active by the operator. operator.

The process sub-system can be in Depressurization state:The process sub-system can be in Depressurization state:• DEPRESSURIZATION: dynamic state which leads to STOP DEPRESSURIZED state. DEPRESSURIZATION: dynamic state which leads to STOP DEPRESSURIZED state.

Following are showed the possible transitions:Following are showed the possible transitions:• DEPRESSURIZATION dynamic state allows the transition from any state to STOP DEPRESSURIZATION dynamic state allows the transition from any state to STOP

DEPRESSURIZED. DEPRESSURIZED.


1.1. Slug Catcher inlet valve “SDV-3111” shall be closedSlug Catcher inlet valve “SDV-3111” shall be closed2.2. Loading line bypass valve “SDV-3112” shall be closed.Loading line bypass valve “SDV-3112” shall be closed.3.3. Discharge pipeline vent valve “BDV-3135” shall be open.Discharge pipeline vent valve “BDV-3135” shall be open.4.4. Station delivery line valve “SDV-3134” shall be closed.Station delivery line valve “SDV-3134” shall be closed.5.5. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be under the set point. The fluid pressure “PIT-3113” upstream the Slug Catcher shall be under the set point. 6.6. The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be under the set The fluid pressure “PIT-3114” & “PIT-3115” in the Inter stage Headers shall be under the set

point.point.7.7. The fluid pressure “PIT-3123” within the Filter Separator shall be under the set point.The fluid pressure “PIT-3123” within the Filter Separator shall be under the set point.8.8. The fluid pressure “PIT-3133” at the station discharge shall be under the set point.The fluid pressure “PIT-3133” at the station discharge shall be under the set point.9.9. The PID-3133 regulator shall be set in AUTO with a predetermined set point.The PID-3133 regulator shall be set in AUTO with a predetermined set point.


MAIN _HEADERS_SYSTEMMAIN _HEADERS_SYSTEM - RULES FOR MANUAL - RULES FOR MANUAL

The state are written in Bold = The state are written in Bold = condition rule is critical, the rule must be followed;condition rule is critical, the rule must be followed; The state are written in Normal = The state are written in Normal = condition rule shall be followed to avoid condition rule shall be followed to avoid

procedures error; procedures error; The state are write in Grey = The state are write in Grey = condition rule could be ignored.condition rule could be ignored. The symbol "-" means: The symbol "-" means: no rules (The state can be in any state including Unknown).no rules (The state can be in any state including Unknown).

Rules for manual:Rules for manual:

Before or immediately after the Main Header depressurization it will be Before or immediately after the Main Header depressurization it will be necessary to depressurize also each single turbine unit if the related necessary to depressurize also each single turbine unit if the related pressure drop across the discharge valve are too high.pressure drop across the discharge valve are too high.

Stopping: Normally this command is not necessary because is executed Stopping: Normally this command is not necessary because is executed automatically when there are no turbine on-load.automatically when there are no turbine on-load.

HP_FUEL_GAS_HEADER - RULES FOR MANUALHP_FUEL_GAS_HEADER - RULES FOR MANUAL

GLYCOL REGENERATION UTILITY SYSTEM - RULES FOR GLYCOL REGENERATION UTILITY SYSTEM - RULES FOR MANUAL COMMANDMANUAL COMMAND

The depressurization can cause the TEG The depressurization can cause the TEG contamination with air.contamination with air.

GLYCOL REGENERATION SYSTEM - RULES FOR MANUAL GLYCOL REGENERATION SYSTEM - RULES FOR MANUAL COMMANDCOMMAND

FUEL GAS SYSTEM-TURBINE A LP - RULES FOR MANUAL FUEL GAS SYSTEM-TURBINE A LP - RULES FOR MANUAL COMMANDCOMMAND

SEAL GAS SYSTEM-TURBINE A LP - RULES FOR MANUAL SEAL GAS SYSTEM-TURBINE A LP - RULES FOR MANUAL COMMANDCOMMAND

LOW PRESSURE TURBINE A - RULES FOR MANUAL COMMANDLOW PRESSURE TURBINE A - RULES FOR MANUAL COMMAND

Beside the control system that manages the station during all normal operation (Distribuited Beside the control system that manages the station during all normal operation (Distribuited Control System - DCS), an independent safety control system shall manages all aspects related to Control System - DCS), an independent safety control system shall manages all aspects related to safety within the station.safety within the station.

In case of emergency, upon reception of specific alarms or upon operators request the safety In case of emergency, upon reception of specific alarms or upon operators request the safety control system shall initiate a series of actions (ESD sequences) in order to put the station or control system shall initiate a series of actions (ESD sequences) in order to put the station or parts of it in a safe configuration.parts of it in a safe configuration.

Four different ESD levels have been identified for Four different ESD levels have been identified for NEFT DASHLARI GCSIINEFT DASHLARI GCSII Gas Compression station. Gas Compression station.

Depending on the emergency situation, these four different ESD levels shall isolate various Depending on the emergency situation, these four different ESD levels shall isolate various sections of the main process facilities and utilities, but also start eventually an automatic sections of the main process facilities and utilities, but also start eventually an automatic Emergency De-pressurization procedure.Emergency De-pressurization procedure.

ESD SYSTEM & CAUSE AND EFFECTESD SYSTEM & CAUSE AND EFFECT

If a shutdown condition is satisfied but a timer, delays the shutdown action, an alarm toIf a shutdown condition is satisfied but a timer, delays the shutdown action, an alarm to operator shall be given with the time remaining to the shutdown.operator shall be given with the time remaining to the shutdown. When the cause disappears a reset of the cause shall be carried out.When the cause disappears a reset of the cause shall be carried out.

ESD SYSTEM & CAUSE AND EFFECT: ESD 1ESD SYSTEM & CAUSE AND EFFECT: ESD 1

UA-3X46:UA-3X46: F&G detection from turbine enclosure unit. F&G detection from turbine enclosure unit. MANUAL SHUTDOWN ESD-1:MANUAL SHUTDOWN ESD-1: Software push button. Software push button.

The lower explosive limit (LEL) of a combustible gas is the smallest amount of the gas that supports

a self-propagating flame when mixed with air (or oxygen). In gas-detection systems, the amount of gas present is specified as a percentage (%) LEL-UEL. Below the LEL% the Gas concentration is not sufficient to generate an explosion. Above the UEL% the Gas concentration is not sufficient to generate an explosion because it does

not contains enough oxygen. The inflammability range is included between LEL and UEL. Outside of this range the gas can not burn.

ESD BATTERY AUTONOMY IS 72 HOURS

ESD SYSTEM & CAUSE AND EFFECT: ESD 1ESD SYSTEM & CAUSE AND EFFECT: ESD 1

ESD SYSTEM & ESD SYSTEM & CAUSE AND EFFECT: ESD 1-ACAUSE AND EFFECT: ESD 1-A Station vent valve BDV-3135 not closed. The effect shall be Station vent valve BDV-3135 not closed. The effect shall be

activated if valve close limit switches feedback is inconsistent activated if valve close limit switches feedback is inconsistent with the DCS full close command SY-3135 and the time delay with the DCS full close command SY-3135 and the time delay has elapsed. has elapsed.

ESD SYSTEM & CAUSE AND EFFECT: ESD 2 & 3ESD SYSTEM & CAUSE AND EFFECT: ESD 2 & 3

MAH-3151:MAH-3151: Instrument Air high dew-point. Instrument Air high dew-point. PALL-3112: (Set point = 1.38 bar)PALL-3112: (Set point = 1.38 bar) SDV-3111:SDV-3111: Station inlet valve SDV-3111 not open. Station inlet valve SDV-3111 not open.

The effect shall be activated if one or more turbine are running and The effect shall be activated if one or more turbine are running and valve open limit switches feedback is inconsistent with DCS full valve open limit switches feedback is inconsistent with DCS full open command SY. open command SY.

UA-3610A: UA-3610A: Glycol Dehydration System Trip (SLIDE 97).Glycol Dehydration System Trip (SLIDE 97). PAHH-3111:PAHH-3111: ESD level 2 shutdown (pressurized plant shutdown) if ESD level 2 shutdown (pressurized plant shutdown) if

a very high pressure is detected upstream the Slug catcher. (Set a very high pressure is detected upstream the Slug catcher. (Set point = 6.2 bar)point = 6.2 bar)

Due to the fact that the settle-out pressure Due to the fact that the settle-out pressure ( the equilibrium ( the equilibrium pressure when your compressor system is tripped pressurized )pressure when your compressor system is tripped pressurized ) is is greater than PSHH-3111 set-point, the shutdown shall be greater than PSHH-3111 set-point, the shutdown shall be inhibited if the turbo-compressors are not on-load (with delay inhibited if the turbo-compressors are not on-load (with delay timer) to allow the plant starting.timer) to allow the plant starting.

LAHH-3121-3122 (SETPOINT = 311 mm); UA3610A:LAHH-3121-3122 (SETPOINT = 311 mm); UA3610A: The Operator The Operator Station shall allow to inhibit those shutdowns with a Password Station shall allow to inhibit those shutdowns with a Password (FILTER BY-PASS PASSWORD & DEHYDRATION BY-PASS (FILTER BY-PASS PASSWORD & DEHYDRATION BY-PASS PASSWORD).PASSWORD).

GLYCOL REGENERATION SUBSYSTEMSGLYCOL REGENERATION SUBSYSTEMS

• When SDV 3613B, SDV 3614B, SDV 3707 When SDV 3613B, SDV 3614B, SDV 3707 close PLC command is active, close limit close PLC command is active, close limit

switch switch feedback signal shall be reached in a feedback signal shall be reached in a predetermined time.predetermined time.

• Emergency shut down from PLC shall not be Emergency shut down from PLC shall not be active. active.

• Shut down from ESD system “XSD-3610”Shut down from ESD system “XSD-3610” shall shall

not be active. not be active.

• The instrument air pressure “PSL 3713” The instrument air pressure “PSL 3713” shall be shall be

inside a predetermined range.inside a predetermined range. • The contactor glycol level “LSHH-3614B” The contactor glycol level “LSHH-3614B”

shall shall be inside a predetermined range.be inside a predetermined range.

• If one of the conditions above mentioned is not

verified a “ Glycol Dehydration Package Trip shall occurred”.

ESD SYSTEM: LP FUEL / SEAL GAS UNIT AESD SYSTEM: LP FUEL / SEAL GAS UNIT A

XSD-3740:XSD-3740: Fuel gas heater NAP-3740 – shutdown. Fuel gas heater NAP-3740 – shutdown. UA-3X47:UA-3X47: Turbo-Compressor unit - Fast stop Depressurized. Turbo-Compressor unit - Fast stop Depressurized.

TAHH-3X43: ( SET POINT = 93 C )TAHH-3X43: ( SET POINT = 93 C ) PAHH-3X30: ( SET POINT = 20,7 bar )PAHH-3X30: ( SET POINT = 20,7 bar ) PAHH-3X53: ( SET POINT - LP = 18,8 bar ) HP - 65 barPAHH-3X53: ( SET POINT - LP = 18,8 bar ) HP - 65 bar

ESD SYSTEM: GAS COOLERESD SYSTEM: GAS COOLER

XSD-323X:XSD-323X: Gas cooler ZMF-323X – shutdown. Gas cooler ZMF-323X – shutdown.

UA-3X47:UA-3X47: Turbo-Compressor unit - Fast stop Depressurized. Turbo-Compressor unit - Fast stop Depressurized.

UA-3X45:UA-3X45: Turbo-Compressor unit - Fast stop Pressurized. Turbo-Compressor unit - Fast stop Pressurized.

PAHH-3X53: ( SETPOINT – LP = 18,8 bar ) HP – 65 barPAHH-3X53: ( SETPOINT – LP = 18,8 bar ) HP – 65 bar

ESD SYSTEM: LP TURBO COMPRESSORESD SYSTEM: LP TURBO COMPRESSOR

XSD-3X42A; XSD-3X242B:XSD-3X42A; XSD-3X242B: Fast stop turbine depressurized. Fast stop turbine depressurized. XSD-3X43:XSD-3X43: Turbo-Compressor unit - Fast stop pressurized. Turbo-Compressor unit - Fast stop pressurized. TALL-3X43:TALL-3X43: ESD generates pressurized fast stop of turbo- ESD generates pressurized fast stop of turbo-

compressor if a very low temperature is detected downstream compressor if a very low temperature is detected downstream the fuel gas heater (the action is time delayed). Due to the the fuel gas heater (the action is time delayed). Due to the fact that the temperature sensing element doesn't work fact that the temperature sensing element doesn't work without gas flow, the shutdown is inhibited if the turbo-without gas flow, the shutdown is inhibited if the turbo-compressor is not running (the on-load status will be used compressor is not running (the on-load status will be used instead of running state).instead of running state).

TAHH-3X43: ( SET POINT = 93 C )TAHH-3X43: ( SET POINT = 93 C ) TALL-3X43: ( SET POINT = 21 C )TALL-3X43: ( SET POINT = 21 C ) PALL-3X30: ( SET POINT = 13,8 bar )PALL-3X30: ( SET POINT = 13,8 bar ) PAHH-3X30: ( SET POINT = 20,7 bar )PAHH-3X30: ( SET POINT = 20,7 bar ) PAHH-3X53: ( SET POINT – LP = 18,8 bar); HP – 65 barPAHH-3X53: ( SET POINT – LP = 18,8 bar); HP – 65 bar

ESD SYSTEM: COMMON AREAESD SYSTEM: COMMON AREA

LALL-3121-3122:LALL-3121-3122:

( SET POINT = 45 mm )( SET POINT = 45 mm )

ESD SYSTEM: UTILITY AREAESD SYSTEM: UTILITY AREA

XSD-1100A: XSD-1100A: MCC- Electrical cut-off.MCC- Electrical cut-off.

XSD-1100B: XSD-1100B: UPS- Electrical cut-off.UPS- Electrical cut-off.

XSD-3151:XSD-3151: Air compressor skid – shutdown. Air compressor skid – shutdown.

XSD-3610:XSD-3610: Glycol regeneration Skid – Glycol regeneration Skid – shutdown.shutdown.

FUEL GAS HP, LP SUBSYSTEMSFUEL GAS HP, LP SUBSYSTEMS The process sub-system can be in Pressurization state:The process sub-system can be in Pressurization state:

• PRESSURIZATION: dynamic state with delivery valves “SDV – 3X30“PRESSURIZATION: dynamic state with delivery valves “SDV – 3X30“ open and vent line “BDV – open and vent line “BDV – 3X40“3X40“ valves

before open (purging) and after closed. It leads to STOPPED PRESSURIZED state.before open (purging) and after closed. It leads to STOPPED PRESSURIZED state.

Following are showed the possible transitions:Following are showed the possible transitions:• PRESSURIZATION dynamic state allows the transition from STOPPED DEPRESSURIZED to PRESSURIZATION dynamic state allows the transition from STOPPED DEPRESSURIZED to

STOPPED STOPPED PRESSURIZED.PRESSURIZED.

In order to update the SUB SYSTEM status to STOP PRESSURIZED status during the execution of In order to update the SUB SYSTEM status to STOP PRESSURIZED status during the execution of PRESSURIZATION PRESSURIZATION

procedure essentially the following conditions and actions shall be verified and followed through:procedure essentially the following conditions and actions shall be verified and followed through:1.1. Manual valves “VBD10-3X10” & “ VBB70” shall be open and operator shall confirm it..Manual valves “VBD10-3X10” & “ VBB70” shall be open and operator shall confirm it..2.2. HP Fuel Gas Header conditions showed hereafter in State Recognized matrix shall be verified..HP Fuel Gas Header conditions showed hereafter in State Recognized matrix shall be verified..3.3. At the beginning Fuel Gas sub system inlet valve “SDV – 3X30“ shall be open. At the beginning Fuel Gas sub system inlet valve “SDV – 3X30“ shall be open. 4.4. Fuel Gas purging shall be carried out . Fuel Gas purging shall be carried out . 5.5. Fuel Gas vent valve “BDV – 3X40“ shall be closed when the purging TIMEOUT is expired. Fuel Gas vent valve “BDV – 3X40“ shall be closed when the purging TIMEOUT is expired. 6.6. Process sub plant pressure “PIT-3X30” shall be above the set point.Process sub plant pressure “PIT-3X30” shall be above the set point.7.7. Vent_Monitoring_1 variable status shall be set.Vent_Monitoring_1 variable status shall be set.8.8. Fuel Gas sub system inlet valve “SDV – 3X30“ shall be closed. Fuel Gas sub system inlet valve “SDV – 3X30“ shall be closed.

PCV ( PRESSURE CONTROL VALVE ) PCV ( PRESSURE CONTROL VALVE ) PSV ( PRESSURE SAFETY VALVE )PSV ( PRESSURE SAFETY VALVE ) SSV ( SLUM SHUT VALVE ) SSV ( SLUM SHUT VALVE ) SDV-BDV ( BLOW DOWN VALVE & SHUT DOWN VALVE ) SDV-BDV ( BLOW DOWN VALVE & SHUT DOWN VALVE ) LS ( LEVEL SWITCH )LS ( LEVEL SWITCH ) LIT ( LEVEL INDICATOR TRASMITTER )LIT ( LEVEL INDICATOR TRASMITTER ) VS ( VIBRATION SWITCH )VS ( VIBRATION SWITCH ) TS ( TEMPERATURE SWITCH )TS ( TEMPERATURE SWITCH ) PS-PDS ( PRESSURE DIFFERENTIAL & PRESSURE SWITCHES )PS-PDS ( PRESSURE DIFFERENTIAL & PRESSURE SWITCHES ) PIT – PDIT ( PRESSURE DIFFERENTIAL INDICATOR & PRESSURE PIT – PDIT ( PRESSURE DIFFERENTIAL INDICATOR & PRESSURE

INDICATOR TRASMITTER )INDICATOR TRASMITTER ) TIT ( TEMPERATURE INDICATOR TRASMITTER )TIT ( TEMPERATURE INDICATOR TRASMITTER )

INSTRUMENTATION OVERVIEWINSTRUMENTATION OVERVIEW

PCV (FUEL GAS) - DESIGN PRINCIPLESPCV (FUEL GAS) - DESIGN PRINCIPLES• On the fuel gas line, connected to HP fuel gas collector, are installed two On the fuel gas line, connected to HP fuel gas collector, are installed two

pressure regulating valves, in order to reduce the station discharge pressure pressure regulating valves, in order to reduce the station discharge pressure at a correct value for Turbines.at a correct value for Turbines.

• To control the fuel gas pressure are installed two PCV is series, one operating To control the fuel gas pressure are installed two PCV is series, one operating (Main) one in stand by ( Monitor ).(Main) one in stand by ( Monitor ).

• The monitor will control the pressure if the main valves fails.The monitor will control the pressure if the main valves fails.

• Regulation of the set pressure can be done using the screw.Regulation of the set pressure can be done using the screw.

• As long as the outlet pressure is above the outlet pressure setting, the pilot As long as the outlet pressure is above the outlet pressure setting, the pilot valve plug remains closed.valve plug remains closed.

• The inlet pressure bleeding through the restrictor along with force from the The inlet pressure bleeding through the restrictor along with force from the main spring, provides downward loading pressure to keep the main valve main spring, provides downward loading pressure to keep the main valve diaphragm and plug assembly tightly shut off.diaphragm and plug assembly tightly shut off.

• When the outlet pressure decreases below the pilot outlet pressure setting, When the outlet pressure decreases below the pilot outlet pressure setting, the pilot plug open.the pilot plug open.

• Loading pressure bleeds downstream through the pilot faster than it can be Loading pressure bleeds downstream through the pilot faster than it can be replaced through the restrictor.replaced through the restrictor.

• This reduces loading pressure on top of the main valve diaphragm and plug This reduces loading pressure on top of the main valve diaphragm and plug assembly and lets the unbalanced force between inlet and loading pressure assembly and lets the unbalanced force between inlet and loading pressure overcome the main spring force to open the diaphragm and plug assembly. overcome the main spring force to open the diaphragm and plug assembly.

• As the outlet pressure rises toward the outlet pressure setting, it compresses As the outlet pressure rises toward the outlet pressure setting, it compresses the pilot diaphragm against the pilot control spring and lets the pilot valve the pilot diaphragm against the pilot control spring and lets the pilot valve plug close.plug close.

• The loading pressure, along with force from the main spring, pushes the The loading pressure, along with force from the main spring, pushes the diaphragm and plug assembly onto the edged seat, producing plug assemblydiaphragm and plug assembly onto the edged seat, producing plug assembly tight shutoff.tight shutoff.

Main Valve

Monitor

PCV (Seal gas)PCV (Seal gas)• On the seal gas line for LPA and LPB compressors are installed two pressure regulating valves, in order On the seal gas line for LPA and LPB compressors are installed two pressure regulating valves, in order

to reduce the station discharge pressure at a correct value for LP compressors.to reduce the station discharge pressure at a correct value for LP compressors.

• To control the seal gas pressure are installed two PCV is series, one operating ( Main ) one in stand by ( To control the seal gas pressure are installed two PCV is series, one operating ( Main ) one in stand by ( Monitor ). Monitor ).

• The monitor will control the pressure if the main valves fails.The monitor will control the pressure if the main valves fails.

• Regulation of the set pressure can be done using the screw 35.Regulation of the set pressure can be done using the screw 35.

Main Valve

Monitor

PSVPSV PSV: Pressure safety valves are designed to open automatically at a pre-determined set pressure level of system pressure and to PSV: Pressure safety valves are designed to open automatically at a pre-determined set pressure level of system pressure and to

achieve a rated relieving capacity at a specified pressure above set point (overpressure) before re-closing at a pressure below achieve a rated relieving capacity at a specified pressure above set point (overpressure) before re-closing at a pressure below the opening point or set pressure (blow down).the opening point or set pressure (blow down).

Scope of pressure safety valves is to protect the equipments against any overpressure (external fire, rupture or other causes). Scope of pressure safety valves is to protect the equipments against any overpressure (external fire, rupture or other causes).

Pressure Safety Valves are installed on:Pressure Safety Valves are installed on:

• Slug Catcher MBF 3111;Slug Catcher MBF 3111;

• Suction Scrubber MBF-3X10:Suction Scrubber MBF-3X10:

• Fuel gas filter separator MAK-3X30:Fuel gas filter separator MAK-3X30:

• Seal gas filter separator MAK-3X50:Seal gas filter separator MAK-3X50:

• Discharge filter separator MAK-3120;Discharge filter separator MAK-3120;

• Glycol contactor MAF-3610;Glycol contactor MAF-3610;

• Regeneration Skid;Regeneration Skid;

• Glycol make up tank MBJ-3710;Glycol make up tank MBJ-3710;

• Glycol flash drum MBD-3710;Glycol flash drum MBD-3710;

• Glycol Cartridge filter MAJ-3710A/B;Glycol Cartridge filter MAJ-3710A/B;

• Glycol carbon filter MAJ-3720.Glycol carbon filter MAJ-3720.

Basically a spring forces opposes the system pressure acting on the valve disc.Basically a spring forces opposes the system pressure acting on the valve disc.

When the system pressure rises above the level of the spring force, the valve opens. When the system pressure rises above the level of the spring force, the valve opens.

As lift begins and fluid enters the chamber, a larger area of the shroud is exposed to the fluid pressure. As lift begins and fluid enters the chamber, a larger area of the shroud is exposed to the fluid pressure.

Since the magnitude of the lifting force (F) is proportional to the product of the pressure (P) and the area exposed to the fluid Since the magnitude of the lifting force (F) is proportional to the product of the pressure (P) and the area exposed to the fluid (A); (F = P x A), the opening force is increased. (A); (F = P x A), the opening force is increased.

This incremental increase in opening force overcompensates for the increase in spring force, causing rapid opening.This incremental increase in opening force overcompensates for the increase in spring force, causing rapid opening.

SSV - DESIGN PRINCIPLESSSV - DESIGN PRINCIPLES• The BM5 seriesThe BM5 series slum shut valve has the task to quickly shut off the gas slum shut valve has the task to quickly shut off the gas

flow when the pressure in control point reaches a fixed set value.flow when the pressure in control point reaches a fixed set value.

• The valve re opening can be made only through a pilot manual The valve re opening can be made only through a pilot manual operation.operation.

• The main features are the follows:The main features are the follows:

1.1. Axial flow valve with shutter valve sliding axially.Axial flow valve with shutter valve sliding axially.

2.2. Flanged connections.Flanged connections.

3.3. Protected seal pad.Protected seal pad.

4.4. Possible to fit in all positions.Possible to fit in all positions.

5.5. Pressure control in one or more points Of installation.Pressure control in one or more points Of installation.

6.6. Staring up following overpressure and or under pressure.Staring up following overpressure and or under pressure.

7.7. Pilot is provided with manual release push button to quickly Pilot is provided with manual release push button to quickly close the slam shut valve in case of emergency or during close the slam shut valve in case of emergency or during maintenance operations..maintenance operations..

8.8. Valve opening can be made manually by turning the eccentric Valve opening can be made manually by turning the eccentric shaft anticlockwise.shaft anticlockwise.

• If the discharge pressure of one compressor exceed the maximum If the discharge pressure of one compressor exceed the maximum allowable pressure, the SSV valve close the fuel gas line and the allowable pressure, the SSV valve close the fuel gas line and the machine is forced to stop. machine is forced to stop.

• The SSV valves are installed on the Fuel gas line for the four turbo The SSV valves are installed on the Fuel gas line for the four turbo compressor and sensing Line is connected to the discharge section of compressor and sensing Line is connected to the discharge section of each compressor.each compressor.

• The seal pad is not hit by the gas flow since it is protected by the pad The seal pad is not hit by the gas flow since it is protected by the pad holder and as a consequence is not affected by any possible dirt holder and as a consequence is not affected by any possible dirt present in the gas.present in the gas.

• When the controlled pressure is within set values of the pilot, this When the controlled pressure is within set values of the pilot, this remains set and prevents the rotation of the eccentric shaft.remains set and prevents the rotation of the eccentric shaft.

• When this pressure varies beyond setting limits, the pilot releases the When this pressure varies beyond setting limits, the pilot releases the eccentric shaft and the valve is brought to its closing position following eccentric shaft and the valve is brought to its closing position following the spring thrust.the spring thrust.

SDV-BDVSDV-BDV

• SDV and BDV are ball valves actuated by a SDV and BDV are ball valves actuated by a pneumatic piston single effectpneumatic piston single effect actuator. actuator.

• SDV are fail closed valves;SDV are fail closed valves;

• BDV are fail open valves;BDV are fail open valves;

• Each actuator is equiped with the following accessories:Each actuator is equiped with the following accessories:

LIQUID LEVEL CONTROL (1/2)LIQUID LEVEL CONTROL (1/2)

• Control of liquid level in the operator’s sump is obtained through the following components:Control of liquid level in the operator’s sump is obtained through the following components:

• LIT: level indicator transmitter provide a local and remote indication of the liquid level inside LIT: level indicator transmitter provide a local and remote indication of the liquid level inside sump. sump.

• Associated to the level have been implemented High level Alarm, Low level Alarm and control of Associated to the level have been implemented High level Alarm, Low level Alarm and control of LV. LV.

• LV: Level control valve is controlled by relevant LT. LV: Level control valve is controlled by relevant LT.

• This valve closes when the liquid reach the high level and closes at low level.This valve closes when the liquid reach the high level and closes at low level.

• SDV: If the liquid drop down to the low low level, the relevant LSLL actives the process shut down SDV: If the liquid drop down to the low low level, the relevant LSLL actives the process shut down (ESD) and the SDV is forced to close. (ESD) and the SDV is forced to close.

• LSLL: Low Low level switch is activated when the liquid reach the lowest level, generating a ESD LSLL: Low Low level switch is activated when the liquid reach the lowest level, generating a ESD signal.signal.

• LSHH. High High level switch is activated when the liquid reach the Highest level, generating a LSHH. High High level switch is activated when the liquid reach the Highest level, generating a ESD signal.ESD signal.

LIQUID LEVEL CONTROL (2/3) - DESIGN PRINCIPLESLIQUID LEVEL CONTROL (2/3) - DESIGN PRINCIPLES

• The level switch operating principles is based on hydrostatic principle (Archimede’s law). The level switch operating principles is based on hydrostatic principle (Archimede’s law).

• The float (1) that indicates the level of liquid is connected via a rod to the small piston (2) in magnetic The float (1) that indicates the level of liquid is connected via a rod to the small piston (2) in magnetic stainless steel within a non-magnetic sump (3).stainless steel within a non-magnetic sump (3).

• This sump (3) is fitted with a tripping unit consisting of a magnet (4) and a micro-switch (5) which are This sump (3) is fitted with a tripping unit consisting of a magnet (4) and a micro-switch (5) which are interconnected by means a levers. interconnected by means a levers.

• When the level of liquid is low “A”, the magnet (4) is at rest.When the level of liquid is low “A”, the magnet (4) is at rest.

• When the level of liquid is high “B”, the magnet (4) is attracted by small piston (2) which causes the When the level of liquid is high “B”, the magnet (4) is attracted by small piston (2) which causes the tripping of the micro-switch (5). tripping of the micro-switch (5).

• The level switch are installed on Slug Catcher, Fuel and Seal Gas Skids pipeline, on filter discharge, on The level switch are installed on Slug Catcher, Fuel and Seal Gas Skids pipeline, on filter discharge, on glycol contactor, on glycol regeneration skid tank.glycol contactor, on glycol regeneration skid tank.

LIQUID LEVEL CONTROL (2/2) - DESIGN PRINCIPLESLIQUID LEVEL CONTROL (2/2) - DESIGN PRINCIPLES

• LIT: level indicator transmitter Type GUIDED WAVE RADAR. LIT: level indicator transmitter Type GUIDED WAVE RADAR.

• LIT provide a local level indication and send to DCS a 4-20 mA signal proportional to the level of liquid LIT provide a local level indication and send to DCS a 4-20 mA signal proportional to the level of liquid inside the sump.inside the sump.

• The The Guided Wave Radar Guided Wave Radar level indicator trasmitter operating principles level indicator trasmitter operating principles is based upon the principle of TDR is based upon the principle of TDR (Time Domain Reflectometry). (Time Domain Reflectometry).

• Pulses of electromagnetic energy are transmitted down a probe. Pulses of electromagnetic energy are transmitted down a probe.

• The pulse is reflected when it reaches a liquid surface and received by the processing electronics. The pulse is reflected when it reaches a liquid surface and received by the processing electronics.

• A microcontroller identifies these level echoes measured, evaluates and converts the signals into level A microcontroller identifies these level echoes measured, evaluates and converts the signals into level information.information.

• The level transmitters are installed on Fuel and Seal Gas Skids pipeline, on inlet Slug Catcher.The level transmitters are installed on Fuel and Seal Gas Skids pipeline, on inlet Slug Catcher.

VIBRATION SWITCH - DESIGN PRINCIPLESVIBRATION SWITCH - DESIGN PRINCIPLES• The Vibraswitch, Model 366 installed in proximity of the coolers, is

sensitive to vibration in a direction perpendicular to its mounting base.

• It contains a vibration detecting mechanism which actives a snap-action switch when the selected level of vibration is exceeded.

• The detecting mechanism consists of an armature suspended on a flexure pivot which is restrained from motion by a permanent magnet (the hold down magnet).

• In the “armed” condition, the armature is held against the stop pin by the hold down magnet.

• The stop pin maintains a precise air gap between the armature and the hold down magnet.

• On the opposite end of the armature, the compression spring provides an adjustable force to oppose the force of the hold down magnet.

• Whenever the peak vibration inertial force (mass x acceleration) plus the adjustable compression spring force exceeds the force of the holding magnet, the armature is released and is pulled into the latching magnet (“tripped” position).

• Simultaneously, it activates the snap-action switch.

• Manually (locally) this mechanism may be reset to the “armed” position, depress the reset button to move the armature away from the latching magnet (“tripped” position) until it is held against the stop pin (“armed” position).

TSTS• TS- Temperature switch: A temperature bulb is partially filled with a chemical liquid. TS- Temperature switch: A temperature bulb is partially filled with a chemical liquid.

• As temperature increase the liquid vaporizes causing an increase in pressure above the liquid. As temperature increase the liquid vaporizes causing an increase in pressure above the liquid.

• At a predetermined pressure the sensing element diaphragm changes its position and transmits a force, proportional At a predetermined pressure the sensing element diaphragm changes its position and transmits a force, proportional to the temperature, to an operating shaft. to the temperature, to an operating shaft.

• The shaft is restrained by an adjustable spring. When the force on the shaft overcomes the spring load the shaft The shaft is restrained by an adjustable spring. When the force on the shaft overcomes the spring load the shaft moves and operates a switch or switches. moves and operates a switch or switches.

• On reduction of the applied temperature the force applied on the shaft also falls, the shaft is restored to its original On reduction of the applied temperature the force applied on the shaft also falls, the shaft is restored to its original position by the spring, and the switch reset.position by the spring, and the switch reset.

• The temperature switches are installed on Coolers downstream pipeline.The temperature switches are installed on Coolers downstream pipeline.

PSPS

• PS- Pressure switch: Process pressure is sensed by a diaphragm that generates a force PS- Pressure switch: Process pressure is sensed by a diaphragm that generates a force proportional to the applied pressure.proportional to the applied pressure.

• This force is opposed by an adjustable spring which, at the point of equilibrium permits This force is opposed by an adjustable spring which, at the point of equilibrium permits movement of an operating rod which actuates a switch.movement of an operating rod which actuates a switch.

• The pressure switches are installed on Slug Catcher upstream pipeline, Turbine Suction & The pressure switches are installed on Slug Catcher upstream pipeline, Turbine Suction & discharge pipeline, on Glycol Regeneration skid.discharge pipeline, on Glycol Regeneration skid.

PDSPDS

• PDS- Pressure Differential switch: Process pressure is sensed by a diaphragm that generates PDS- Pressure Differential switch: Process pressure is sensed by a diaphragm that generates a force proportional to the difference between two pressures applied to either side of the a force proportional to the difference between two pressures applied to either side of the diaphragm. diaphragm.

• The force is opposed by a control spring which, at the point of equilibrium permits movement The force is opposed by a control spring which, at the point of equilibrium permits movement of an operating rod which actuates a switch.of an operating rod which actuates a switch.

• The pressure differential switches are installed across the inlet valve SDV 3111, across the The pressure differential switches are installed across the inlet valve SDV 3111, across the turbines Suction valve SDV 3X10.turbines Suction valve SDV 3X10.

PIT - PDITPIT - PDIT• The digital transmitters, Model 364 are communication field devices equipped with a microprocessor.The digital transmitters, Model 364 are communication field devices equipped with a microprocessor.

• Those pressure transmitters are installed on Slug Catcher upstream & downstream pipeline, on Inter stage Header Those pressure transmitters are installed on Slug Catcher upstream & downstream pipeline, on Inter stage Header pipeline , Fuel and Seal Gas Skids pipeline, on gas station discharge pipeline.pipeline , Fuel and Seal Gas Skids pipeline, on gas station discharge pipeline.

• For bidirectional communication, a signal is superimposed on the 4 - 20 mA output signal via the HART protocol. For bidirectional communication, a signal is superimposed on the 4 - 20 mA output signal via the HART protocol.

• Using the graphic user interface, one can configure, query and test the trasmitter.Using the graphic user interface, one can configure, query and test the trasmitter.

• One can also communicate with the transmitter using a handheld terminal.One can also communicate with the transmitter using a handheld terminal.

• For on site operation, there is a key available on the equipment electronic system with which the operator can adjust For on site operation, there is a key available on the equipment electronic system with which the operator can adjust the zero and span.the zero and span.

• In combination with an optionally installed graphic LCD indicator, the transmitter can be configured and In combination with an optionally installed graphic LCD indicator, the transmitter can be configured and parameterized with the four local operating keys.parameterized with the four local operating keys.

• The measuring range is performed by silicon pressure sensor.The measuring range is performed by silicon pressure sensor.

• An incompressible silicone oil fluid is used to transfer pressure from the An incompressible silicone oil fluid is used to transfer pressure from the separating process diaphragm separating process diaphragm to the to the measuring diaphragm measuring diaphragm sense element .sense element .

• Four piezo resistor doped in the measuring diaphragm change their impedances.Four piezo resistor doped in the measuring diaphragm change their impedances.

• This pressure proportional internal output voltage is converted by the electronics system into an electric 4 – 20 mA This pressure proportional internal output voltage is converted by the electronics system into an electric 4 – 20 mA output signal.output signal.

TITTIT• The digital transmitters, Model TTF300 are communication field devices employing microprocessor controlled The digital transmitters, Model TTF300 are communication field devices employing microprocessor controlled

electronics.electronics.

• Those temperature transmitters are installed on Slug Catcher upstream pipeline, Fuel and Seal Gas Skids pipeline, on Those temperature transmitters are installed on Slug Catcher upstream pipeline, Fuel and Seal Gas Skids pipeline, on gas station discharge pipeline.gas station discharge pipeline.

• For bidirectional communication, a signal is superimposed on the 4 - 20 mA output signal via the HART protocol. For bidirectional communication, a signal is superimposed on the 4 - 20 mA output signal via the HART protocol.

• Using the graphic user interface, one can configure, query and test the trasmitter.Using the graphic user interface, one can configure, query and test the trasmitter.

• One can also communicate with the transmitter using a handheld terminal.One can also communicate with the transmitter using a handheld terminal.

• In combination with an optionally installed graphic LCD indicator, the transmitter can be configured and In combination with an optionally installed graphic LCD indicator, the transmitter can be configured and parameterized with the four local operating keys.parameterized with the four local operating keys.

• The temperature sensitive sensor is the heart of the thermometer series Sensy temp TSP.The temperature sensitive sensor is the heart of the thermometer series Sensy temp TSP.

• The TSP331 The TSP331 Sensy tempSensy temp temperature sensors use both Pt100 Resistive Temperature Detectors (RTD) for temperature temperature sensors use both Pt100 Resistive Temperature Detectors (RTD) for temperature measurement. measurement.

• The Pt100 RTD exhibits a resistance of 100 Ω at 0 °C.The Pt100 RTD exhibits a resistance of 100 Ω at 0 °C.

• Temperature is sensed by measuring the change in resistance of the RTD. Temperature is sensed by measuring the change in resistance of the RTD.

• As temperature increases, the resistance of the RTD also increases. As temperature increases, the resistance of the RTD also increases.

• The signal from the RTD is evaluated by a microprocessor inside the temperature control monitor. The signal from the RTD is evaluated by a microprocessor inside the temperature control monitor.

F&G SYSTEM (Flame detector)F&G SYSTEM (Flame detector)• Fire is a phenomenon of combustion. Combustion is the continuous chemical reaction of a reducing agent (fuel) and an Fire is a phenomenon of combustion. Combustion is the continuous chemical reaction of a reducing agent (fuel) and an

oxidizing agent (oxygen, etc.) with the evolution of thermal energy (heat). oxidizing agent (oxygen, etc.) with the evolution of thermal energy (heat).

• Fire is usually manifested in heat (IR), smoke, light (visible), and flame (UV). Fire is usually manifested in heat (IR), smoke, light (visible), and flame (UV).

• Flame is the gaseous region of a fire where vigorous combustion chain reactions take place. Flame is the gaseous region of a fire where vigorous combustion chain reactions take place.

• These reactions emit radiation covering the Infrared, Ultraviolet and the Visible Spectral Regions. These reactions emit radiation covering the Infrared, Ultraviolet and the Visible Spectral Regions.

• Ultraviolet/Infrared (UV/IR) FL3100 Flame Detector which detects the Ultraviolet and Infrared spectral regions of flame, Ultraviolet/Infrared (UV/IR) FL3100 Flame Detector which detects the Ultraviolet and Infrared spectral regions of flame, contains an ultraviolet phototube that responds to Ultraviolet (UV) radiation in the 185 to 260 nanometer region.contains an ultraviolet phototube that responds to Ultraviolet (UV) radiation in the 185 to 260 nanometer region.

• When the radiation from a flame reaches the cathode plate within the UV detector tube, electrons are ejected from the When the radiation from a flame reaches the cathode plate within the UV detector tube, electrons are ejected from the cathode plate.cathode plate.

• These electrons are accelerated towards the positively charged anode of the tube.These electrons are accelerated towards the positively charged anode of the tube.

• They collide with molecules of an ionizable gas, with which the tube is filled.They collide with molecules of an ionizable gas, with which the tube is filled.

• This emits more electrons and producing an avalanche condition more electrons are realesed which creates a This emits more electrons and producing an avalanche condition more electrons are realesed which creates a momentary electron flow from the cathode to anode.momentary electron flow from the cathode to anode.

• This momentary current (pulse) recurs at a rate proportional to the intensity of the UV radiation.This momentary current (pulse) recurs at a rate proportional to the intensity of the UV radiation.

• The Model FL3101 UV Flame Detector processes these UV pulses with a microprocessor and produces a 4 to 20 mA The Model FL3101 UV Flame Detector processes these UV pulses with a microprocessor and produces a 4 to 20 mA signal.signal.

F&G SYSTEM (Gas detector)F&G SYSTEM (Gas detector)• The Model S4000C is an Intelligent Sensor for the detection of The Model S4000C is an Intelligent Sensor for the detection of

combustible gases and vapors. combustible gases and vapors.

• The microprocessor-based electronics process information at the The microprocessor-based electronics process information at the sensor site, within an explosion-proof housing. sensor site, within an explosion-proof housing.

• A digital display provides indications and display codes that can A digital display provides indications and display codes that can be viewed through a window in the cover. be viewed through a window in the cover.

• A red LED above the digital display signifies an ALARM condition, A red LED above the digital display signifies an ALARM condition, while a red LED below the digital display signifies a WARN while a red LED below the digital display signifies a WARN condition. condition.

• A coil shaped platinum wire is coated with suitable metal oxides A coil shaped platinum wire is coated with suitable metal oxides and afterwards the sensor or bead is treated with a catalyst such and afterwards the sensor or bead is treated with a catalyst such as platinum.as platinum.

• The sensor is called “catalytic” sensor because the use of the The sensor is called “catalytic” sensor because the use of the catalyst is the main ingredient involved in the proper functioning catalyst is the main ingredient involved in the proper functioning of the sensor. of the sensor.

• The catalytic bead sensor converts the combustible materials to The catalytic bead sensor converts the combustible materials to heat.heat.

• A change in heat is then converted to a change in resistence, A change in heat is then converted to a change in resistence, which can be measured.which can be measured.

• As a combustible material is converted to heat, the resistence of As a combustible material is converted to heat, the resistence of the active bead increases, causing the voltage drop across each the active bead increases, causing the voltage drop across each bead to be different.bead to be different.

• This difference is proportional to the amount of combustible gas This difference is proportional to the amount of combustible gas that is present.that is present.

• The voltage from the sensor is amplified and fed to an Analogic The voltage from the sensor is amplified and fed to an Analogic and Digital (A/D) converter and than made available to the and Digital (A/D) converter and than made available to the microprocessor.microprocessor.

• Analog signal (4-20mA) produced by microprocessor, provides Analog signal (4-20mA) produced by microprocessor, provides remote indications of the sensor’s operation. remote indications of the sensor’s operation.

F&G SYSTEM: POWER CONTROL ROOMF&G SYSTEM: POWER CONTROL ROOM

F&G SYSTEM: FIRE DETECTORS LAYOUTF&G SYSTEM: FIRE DETECTORS LAYOUT

F&G DETECTORS LAYOUT FOR REGENERATION SKIDF&G DETECTORS LAYOUT FOR REGENERATION SKID

F&G SYSTEM: F&G SYSTEM: GAS DETECTORS LAYOUTGAS DETECTORS LAYOUT

THANKS FOR YOUR THANKS FOR YOUR ATTENTIONATTENTION

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SYSTEM SECURITYSYSTEM SECURITY

final presentation

Business

inter stage

equilibrium

glycol regeneration

heater control

glycol regeneration

glycol utility

alarm glycol

graphic user