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SPM-721 Advanced Distillation Operator Training Manual

Version 6.3

Information: 1-800-730-0760 Simtronics Corporation +1-732-747-0322 P.O. Box 38 1-732-224-0009 Fax Little Silver, NJ 07739-0038 USA Technical Support: 1-800-730-0760 [email protected] +1-732-869-6651 Document Revision 3

SPM-721 Manual Operator

Doc Revision 3 DSS-100 Version 6.3

Front Matter

Copyright Notice

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SPM-721 Advanced Distillation Contents

Topic See Page Introduction 4 Process Description 5 Process Schematics 10 Instrumentation 15 Pre-Startup 29 Startup 30 Shutdown 37 Emergency Operations 42 Profitability Calculations 44 Critical Safety Performance 45 Virtual Field Operator 46 Appendix: Standard Score Details 54



Introduction

Simtronics’ Advanced Distillation simulator program represents a typical industrial

distillation plant consisting of a distillation column, feed storage tank, two product storage tanks, an off-spec tank and a flare system. The feed to the unit is a raw light gasoline feed produced from primary fractionation of natural gas liquids (NGL). In the petroleum industry the distillation column is commonly called a debutanizer since it removes butane and lighter compounds from the feed to produce a stabilized (less volatile) liquid product. The feed mainly contains a range of alkane hydrocarbons: propane through hexane. The purpose of the unit is to separate the lighter components (principally butane and lighter components) from the heavier components (pentane and heavier components). All products are removed as liquids and are routed to product storage tanks. Off-Spec product can be transferred to the Off-Spec Storage Tank. A flare system is included in the model and is present in the event that a small amount of light gas is produced. The flare system is intended to burn any light gas produced during operations. A full range of operations can be learned and practiced on the Distillation Column with Tank Farm and Flare System simulator. These include normal, startup, shutdown, and emergency shutdown procedures. The rest of this manual describes the Advanced Distillation simulation and provides detailed operating procedures and exercises for training.



Process Description

Advanced Distillation Process Description - Overview

Refer to Schematic 2 in the “Process Schematics” section below. Hydrocarbon feed enters the process and is stored in a spherical Feed Tank, V-101. The feed is pumped to Distillation Column, T-401. To effect separation in the Distillation Column, heat is provided to the process by:

• A Feed Preheater, E-400, in which heat is recovered from the distillation column bottoms by the distillation column feed.

• A Reboiler, E-402, via hot oil. Distillation Column overhead vapor is a reasonably pure butane stream containing a small amount of propane. The overhead vapor is condensed in Condenser, E-401, by cooling water before separation in the Reflux Drum, D-401. The Reflux Drum pressure is controlled by the Condenser and its bypass control valve. Uncondensed vapor in the Reflux Drum, if any, is sent to the flare system. Condensate from the Reflux Drum is pumped by Reflux Pumps, P-401A/B, with a portion of the liquid returned as reflux to the Distillation Column. The balance of the condensate is pumped to the Light Product Tank, V-901. The Light Product Tank provides short term product storage prior to being pumped by the Light Product Pump, P-901, for delivery. The Distillation Column operates at a pressure sufficiently high to transfer its bottoms liquid to atmospheric product storage. As indicated earlier, heat is recovered by heating feed with distillation column bottoms in E-400. If necessary, Distillation Column bottoms is further cooled by cooling water in the Bottoms Cooler, E-403 before entering the Heavy Product Tank, V-902. The Heavy Product Tank provides short term product storage prior to being pumped by the Heavy Product Pump, P-902, for delivery. Alternatively, any off-spec product can be transferred to the Off-Spec Tank, V-903, for reprocessing by sending material back to the Feed Tank, V-101, or to another processing unit. The Flare System collects pressure safety valve (PSV) releases from all four tanks and from vent and PSV release from the Distillation Column in the Flare Header. The releases, typically vapor, are sent to the Liquids Knock Out Drum, D-951, to separate any liquid releases that may occur in case a vessel is overfilled. Any liquid collected in the drum is pumped by Knock Out Liquid Pumps, P-951A/B, to liquids disposal at battery limits. Remaining vapor from D-951 is sent to the Seal Drum, D-952, where the vapor is contacted with utility water to create a seal that prevents air from back-flowing into V-951 and the flare header. Water is collected on the spillover side of the Seal Drum and pumped to water disposal by Seal Water Pumps, P-952A/B. Vapor from the Seal Drum is combined with fuel gas in the Flare Stack, FS-952, where it is burned before being released to the atmosphere.

Continued on next page



Process Description, continued

Feed Tank

Refer to Schematic 3 in the “Process Schematics” section below. The Feed Tank, V-101, receives raw feed from Unit A at battery limits under flow control from the upstream unit. The Feed Tank is designed to combine fresh feed and rerun feed from the Tank Farm. Fresh Feed normally enters the Feed Tank via XV-101A. Fresh feed may also bypass the Feed Tank and pass on to the Distillation Column (T-401) through XV-101B. Normally, no rerun from Off-Spec Tank, V-903, is processed. The design feed composition to the unit is:

Component Mole % Weight % Propane (C3H8) 1.316 0.902 Butane (C4H10) 65.074 58.816 Pentane (C5H12) 21.806 24.465 Hexane (C6H14) 11.803 15.817

Under startup, shutdown and upset conditions the unit may produce off-spec product. If desired, and as noted above, the off-spec product from the Tank Farm can be rerun by combining with fresh feed in the Feed Tank. The pressure of V-101 floats depending on the vapor pressure of the tank contents. In case of overpressure due to high vapor pressure or if the tank is overfilled, PSV-101 will release gas and/or liquid to the Flare Header.

Feed System Refer to Schematic 4 in the “Process Schematics” section below. Liquid from the Feed Tank is transferred to the Distillation Column via the Distillation Feed Pumps, P-400 A/B. The feed pumps are electric motor driven pumps and each has the same capacity. Normally, only one pump is in service. Feed which bypasses the Feed Tank via XV-101B is combined with the pump discharge before entering the Feed Preheater, E-400. The Feed Preheater recovers heat from the Distillation Column bottoms (light gasoline) which facilitates component separation downstream in the Distillation Column and reduces the heat input required from hot oil. The direct feed line is used in case the Feed Pumps, P-400A/B, are out of service or in circumstances where the feed rate to the Distillation Column needs to be less than the flow rate from Unit A at battery limits. In this latter circumstance, the Feed Pumps should normally be stopped.





Distillation Column

Refer to Schematic 5 in the “Process Schematics” section below. The Distillation Column, T-401 consists of 36 distillation trays with the feed introduced on tray 24 (bottom-most tray is tray 1). The feed liquid is distilled into a butane product produced in the overhead section of the Distillation Column and a liquid product (principally pentane) from the bottom of the column. Additional heat is supplied to the Distillation Column by the Reboiler, E-402. The reboiler uses hot oil to provide supplemental heat for component separation. The Distillation Column operates at a pressure sufficiently high so that pumping the column bottoms product to storage is not required. The heavy liquid bottoms product is normally used to preheat to the Distillation Column. Residual heat is removed by cooling water in the Bottoms Cooler, E-403. The cooled heavy product is normally routed to Heavy Product Tank V-902. Alternatively, it can be routed to the Off-Spec Storage Tank, V-903, or directly to the Feed Tank, V-101 for reprocessing. Top vapor from T-401 is sent to Condenser E-401. The Distillation Column is protected from overpressure by PSV-401 which routes any release to the Flare Header. The set pressure of PSV-401 is 12.8 BARG.

Overhead System

Refer to Schematic 6 in the “Process Schematics” section below. Typically, all the vapor from the top of the Distillation Column T-401 is condensed in Condenser, E-401. The condenser uses cooling water from battery limits to cool and condense the overhead vapor down to 33 DEG C. The condensed liquid from E-401 enters the bottom of the Reflux Drum D-401. The elevation of E-401 relative to D-401 is such that the condensate it produces will form a liquid seal between the shell-side inlet of E-401 and the vapor space of D-401. The liquid level within E-401 will change until the condensing rate matches the overhead vapor flow rate from T-401. Increasing the pressure in D-401 will back up liquid in E-401 which, in turn, will cause a lower condensing rate in E-401. Because of the lower condensing rate, the pressure builds in T-401 until it can push the liquid level in E-401 lower to increase the condensing rate until it balances with the overhead vapor rate from T-401. Therefore, changing the pressure of D-401 will change the pressure of T-401. In order to increase the pressure of D-401, a hot vapor bypass line is provided around E-401 to admit hot vapor from the overhead of T-401 directly to the vapor space of D-401. To decrease the pressure of D-401, some of the vapor from D-401 may be vented to flare. A split-range control loop is used to automatically control the hot vapor bypass and flare control valves. In case the pressure of D-401 cannot be controlled, a second automatic pressure vent to flare is provided. The Reflux Drum is protected from overpressure by PSV-402 which routes any release to the Flare Header. The set pressure of PSV-402 is 12.8 BARG. The liquid collected in D-401 is product butane and is pumped by Reflux Pumps P-401A/B under level/flow control to the Light Product Storage Tank, V-901. Before entering V-901, that stream is cooled by cooling water in E-404, the Overhead Cooler. A separate portion of the reflux is under flow control with the liquid returning to the Distillation Column. The reflux pumps are electric motor driven pumps and are of the same capacity. Normally, only one pump is in service.





Product and Off-Spec Tanks

Refer to Schematic 7 in the “Process Schematics” section below. There are three spherical storage tanks which make up the product portion of the Tank Farm (the other is the Feed Tank V-101). The Light Product Tank, V-901, is supplied by the Reflux Pumps, P-401A/B, via the Overhead Cooler, E-404. The Light Product Tank contains liquid with a high butane content. Liquid is removed from the Light Product Tank by the Light Transfer Pump, P-901, under level control to Unit C. The pressure of V-901 floats depending on the vapor pressure of the tank contents. In case of overpressure due to high vapor pressure or if the tank is overfilled, PSV-901 will release gas and/or liquid to the Flare Header. The Heavy Product Tank, V-902, is supplied by the Distillation Column, T-401, bottoms via the Bottoms Cooler, E-403. The Heavy Product Tank contains liquid rich in pentane with some hexane and a small amount of butane. Liquid is removed from the Heavy Product Tank by the Heavy Transfer Pump, P-902, under level control to Unit E. The pressure of V-902 floats depending on the vapor pressure of the tank contents. In case of overpressure due to high vapor pressure, or if the tank is overfilled, PSV-902 will release gas and/or liquid to the Flare Header. The Off-Spec Tank, V-903, can accept feed from the Reflux Drum, D-401, or the Distillation Column, T-401, bottoms. The Off-Spec Tank will contain off-spec liquid. This liquid is removed from the Off-Spec Tank by the Off-Spec Transfer Pump, P-903, under level control. The liquid is transferred to Unit D or returned for rerun to the Feed Tank, V-101. The pressure of V-903 floats depending on the vapor pressure of the tank contents. In case of overpressure due to high vapor pressure or if the tank is overfilled, PSV-903 will release gas and/or liquid to the Flare Header.





Flare System Refer to Schematic 8 in the “Process Schematics” section below. Any releases to the Flare Header are routed to the Liquids Knock Out Drum, D-951. This includes:

• Flare system purge nitrogen • Releases from the Distillation Column, T-401, pressure relief valve, PSV-401 • Releases from the Reflux Drum, D-401, pressure relief valve, PSV-402 • D-401 vapor via

o PV-412B, the split range pressure release control valve o PV-413, the high pressure control valve

• Releases from the Feed Tank, V-101, pressure relief valve, PSV-101 • Releases from the Light Product Tank, V-901, pressure relief valve, PSV-901 • Releases from the Heavy Product Tank, V-902, pressure relief valve,

PSV-902 • Releases from the Off-Spec Tank, V-903, pressure relief valve, PSV-903

Normally, there is a nominal flow of nitrogen added at the end of the Flare Header to sweep any leaks from the PSVs or small vent flows from Reflux Drum, D-401, to D-951. This also inhibits the infiltration of air from the Flare Stack, FS-952, into the header. The combined feeds from the Flare Header enter the Liquids Knock Out Drum, D-951, where liquid, if any, will accumulate at the bottom of the drum. This liquid will be transferred from the Liquids Knock Out Drum by the Knock Out Liquids Pumps, P-951A/B, under level control. The Knock Out Liquids Pumps are electric motor driven pumps and are of the same capacity. Normally, no pump is in service. An interlock system will automatically start P-951A if the level of D-951 exceeds 30% and will automatically start P-951B if the level exceeds 60%. Vapor from the Liquids Knock Out Drum, D-951, feeds the left side of the Seal Drum, D-952 which is normally completely full of water. Under no-release conditions, the nitrogen sweep gas to the Flare Header will bubble through the water in the left side of the Seal Drum and then flow to the Flare Stack, FS-952. The water seal prevents infiltration of air back into D-951 and the Flare Header under no-release conditions. The Seal Drum is partitioned with a vertical baffle separating two sides. Utility water under flow control feeds the left side of the drum. Once the left side is water full, water will spill over the baffle to the right side of the Seal Drum. A small opening is cut in the base of the baffle to allow drainage of water from the seal-side at shutdown. Water collected in the right side of the Seal Drum will be pumped to disposal via Seal Water Pumps, P-952A/B, under level control. The Seal Water Pumps are electric motor driven pumps and are of the same capacity. Normally, only one pump is in service. The vapor from D-951 will combine with draft air entering at openings in the base of the Flare Stack. The draft air provides oxygen which will burn fuel gas fed to a burner ring within the stack. The Flare Stack contains a Pilot Flame Generator (X-955) which provides a steady ignition flame at the burner ring. A small gas flow keeps the Flare Stack warm so as to have a sufficient flow of draft air in case of a release of hydrocarbons into the Flare Header. During a release to the Flare Header, the temperature of the Flare Stack will increase which will, in turn, provide more draft air.



Process Schematics

Schematics List

The Advanced Distillation simulator has a total of 8 process schematics as follows:

- 2 – Overview - 3 – Feed Tank - 4 – Feed System - 5 – Distillation Column - 6 – Overhead System - 7 – Product & Off-Spec Tanks - 8 – Flare System

Note: schematic 1 on the simulator is a thumbnail selection menu of these schematics. There are additional schematics provided on the simulator as follows:

- 9 through 20 – Field operations (for use with the Virtual Field Operator if purchased for simulator)

- 21 – Profitability - 22 – Critical Safety Performance

The last two schematics show the details of how the instant profit and the critical safety penalty are calculated. These variables are indicated in the upper left of Schematic 2 – Overview.

Schematic 2 Overview




Process Schematics, continued

Schematic 3 Feed Tank

Schematic 4 Feed System





Schematic 5 Distillation Column

Schematic 6 Overhead System





Schematic 7 Product & Off-Spec Tanks

Schematic 8 Flare System





Schematic 21 Profitability

Schematic 22 Critical Safety Performance



Instrumentation

Overview This section describes the controls and instruments of the Advanced Distillation

simulator program. Refer to Schematics 3 through 8 in the “Process Schematics” section above for details of the connections. There are no advanced controls in the unit.

Feed Tank Controls and Instruments

Refer to Schematic 3 in the “Process Schematics” section above. Total fresh feed to the process unit is indicated on FI-100. The feed rate is normally controlled in Unit A at battery limits when feed is routed to Feed Tank, V-101. Switch XV-101A is used to open and close the feed to tank isolation valve XV-101A. Switch XV-101B is used to open and close the feed tank bypass valve XV-101B. Normally XV-101A is open and XV-101B is closed. The liquid level in spherical Feed Tank, V-101, is displayed on level controller LIC-101 which is cascaded to the downstream feed flow controller FIC-400 for the Distillation Column, T-401. The pressure in V-101 is indicated on PI-101.

Feed System Controls and Instruments

Refer to Schematic 4 in the “Process Schematics” section above. Pumps P-400A/B transfer feed to the Distillation Column, T-401. Switches HS-400A and HS-400B are used to change the states of the motors for Distillation Feed Pumps P-401A and P-401B, respectively. The temperature and pressure of the combined feed (from Feed Tank V-401 and its bypass) are indicated on TI-400 and PI-400, respectively. The feed analyzer provides four composition measurements:

• AI-400A – Mole % Propane • AI-400B – Mole % Butane • AI-400C – Mole % Pentane • AI-400D – Mole % Hexane

As indicated earlier, the total feed to the Distillation Column is controlled by FIC-400 (receives the output signal from LIC-101) and adjusts the valve opening of FV-400. FIC-400 is normally in cascade mode. In the case where the Feed Tank is bypassed and Unit A directly feeds into the discharge of P-400A/B, FIC-400 should be placed into either automatic or manual mode. Also, pumps P-400A/B should be switched off in this mode of operation unless they are needed to empty the Feed Tank. When FIC-400 is in automatic mode, the feed to the Distillation Column will be controlled by FIC-400. The setpoint of FIC-400 should be at least a bit less than the demand flow of the flow controller in Unit A (normally 1950 BPD210 M3/D); otherwise the controllers will fight each other. In case FIC-400 is in manual mode, the flow controller in Unit A will try to regulate the feed flow. In this case, make sure that the feed control valve FV-400 is fully open to allow Unit A’s controller to properly regulate the flow. Distillation Column feed temperature (tube side pass) is indicated on TI-402. The temperature at the outlet of the shell side pass (Distillation Column Bottoms) can be observed on TI-415.




Instrumentation, continued

Distillation Column Controls and Instruments

Refer to Schematic 5 in the “Process Schematics” section above. As indicated earlier, the feed temperature to the Distillation Column is displayed on TI-402. The pressure at the top of Distillation Column T-401 is indicated on PI-403. A second independent pressure indicator, PAH-403, is used as a trip sensor for the Distillation Column Reboiler Interlock I-401 (see Interlock I-401 below). The temperature of vapor leaving the top of T-401 is indicated on TI-403. TI-404, TI-405, TI-406 and TI-407 indicate the temperatures of trays 15, 13, 8 and 6 of T-401, respectively (recall that the bottom of the column is tray 1 while the top of the column is tray 17). TIC-408 controls the temperature of tray 3 by adjustment of the setpoint of hot oil flow controller FIC-004. FIC-004 will adjust the valve opening of FV-004. The temperature of tray 1 liquid to the Distillation Column Reboiler is indicated on TI-409. The temperature of the NGL leaving the Reboiler, E-402, is indicated on TI-410. The temperature of T-401 bottoms is indicated on TI-411. For the Reboiler, E-402, the hot oil supply pressure is indicated on PI-001. The temperature of the hot oil supply is indicated on TI-001. The flow of hot oil to E-402 is controlled by FIC-004 which adjusts the position of FV-004. The temperature of hot oil leaving E-402 is indicated on TI-004. If the Distillation Column Reboiler Interlock I-401 is active, FIC-004 will be locked in manual with an output of 0% to prevent flow of hot oil to E-402. The flow of Distillation Column bottoms is managed by HIC-415 which controls a 3-way valve. At an output of 100%, all of the bottoms flow will be directed to E-400, the Distillation Column Preheater. When the output of HIC-415 is 0%, all of the bottoms flow will bypass E-400 entirely and feed directly into Bottoms Cooler, E-403. The tube side inlet temperature for E-403 is indicated on TI-416. After transferring heat to cooling water in E-403, the tube side outlet temperature from E-403 is displayed on TI-417. The cooling water supply temperature is indicated on TI-021 and the cooling water outlet temperature from E-403 is indicated on TI-025. The cooling water flow rate can be adjusted with hand controller HIC-025 which adjusts the opening of control valve HV-025. The pressure drop across the top section of T-401 is indicated on PDI-401. The pressure drop across the lower section of T-401 is indicated on PDI-402. The level of liquid in the bottom of T-401 is controlled by LIC-411 which adjusts the setpoint of bottoms flow controller FIC-411. FIC-411 controls the bottoms flow from T-401 to Bottoms Storage by adjustment of the position of FV-411. The butane content of the bottoms from T-401 is indicated on AI-411.





Overhead Controls and Instruments

Refer to Schematic 6 in the “Process Schematics” section above. The process stream outlet temperature from Distillation Column Condenser E-401 is indicated on TI-412. The cooling water flow to E-401 is controlled by HIC-024 with the cooling water outlet temperature displayed on TI-024. The pressure of Reflux Drum, D-401, is controlled by PIC-412 which is a split range controller. PIC-412 controls both PV-412A (0-50%) and PV-412B (50-100%). Only one of these two valves will be open at any point in time. When the Reflux Drum pressure is low, PV-412A is open (PV-412B is closed). Conversely, when the Reflux Drum pressure is high, PV-412B is open (PV-412A is closed). The graph below shows the relationship between PIC-412 and the positions of the valves it controls.

The flow of gas through PV-412B to flare is indicated on FI-412. A second independent pressure controller PIC-413 adjusts the position of PV-413. PIC-413 should have a higher pressure setpoint than PIC-412 and will only open PV-413 if PIC-412 is unable to control the pressure of D-401. The level of liquid in Reflux Drum D-401 is controlled by LIC-412 which adjusts the setpoint of overhead product flow controller FIC-414. An independent level is indicated on LAH-412 which is used for the Reboiler Interlock I-401 (see Interlock I-401 below). The temperature of liquid leaving D-401 is indicated on TI-413. Switches HS-401A and HS-401B are used to change the states of the motors for Reflux Pumps P-401A and P-401B, respectively. The flow of reflux to T-401 is controlled by FIC-413 which adjusts the position of FV-413. The flow of light product to storage is controlled by FIC-414 which adjusts the position of FV-414. The concentration of pentane and higher components in the light product indicated on AI-414. HIC-026 adjusts the position of Overhead Cooler, E-404 cooling water supply valve HV-026. The temperature of light product leaving E-404 is indicated on TI-418. The temperature of the cooling water return is indicated on TI-026.





Product & Off-Spec Tanks Controls and Instruments

Refer to Schematic 7 in the “Process Schematics” section above. Light Product from Reflux Drum, D-401 bottoms can be forwarded to the:

• Light Product Tank, V-901, by opening isolation valve XV-901, or • Off-Spec Tank, V-903, by opening isolation valve XV-903A.

Heavy Product from Distillation Column, T-401 bottoms can be forwarded to the:

• Heavy Product Tank, V-902, by opening isolation valve XV-902, or • Off-Spec Tank, V-903, by opening isolation valve XV-903B, or • Feed Tank, V-101, by opening isolation valve XV-101C.

Product is transferred from the Light Product Tank, V-901, by level controller LIC-901 which adjusts valve LV-901. Switch HS-901 is used to change the state of the motor for the Light Transfer Pump P-901. Product flow is displayed on FI-901 and is transferred to Unit C. The pressure in V-901 is indicated on PI-911. Product is transferred from the Heavy Product Tank, V-902, by level controller LIC-902 which adjusts valve LV-902. Switch HS-902 is used to change the state of the motor for the Heavy Transfer Pump P-902. Product flow is displayed on FI-902 and is transferred to Unit E. The pressure in V-902 is indicated on PI-912. Off-Spec material is transferred from the Off-Spec Tank, V-903 by level controller LIC-903. Switch HS-903 is used to change the state of the motor for the Off-Spec Transfer Pump P-903. Liquid flow is displayed on FI-903. Off-Spec material can be forwarded to:

• Feed Tank, V-101, by opening isolation valve XV-101D for reprocessing, or • Unit D at battery limits by opening isolation valve XV-903C.

The pressure in V-903 is indicated on PI-913.





Flare System Controls and Instruments

Refer to Schematic 8 in the “Process Schematics” section above. HIC-960 adjusts the position of valve HV-960 which will admit a small nitrogen purge stream to the Flare Header. The nitrogen flow is indicated on FI-960. The pressure of the Liquids Knock Out Drum, D-951 is shown on PI-951. The liquid level in D-951 is controlled by LIC-951, which adjusts valve LV-951. The flow of liquid from the bottom of D-951 is measured by FI-951. Switches HS-951A and HS-951B are used to change the state of the motor for the Knock Out Drum Liquids Pumps, P-951A and P-951B, respectively. An independent level for D-951 is indicated on LAH-951 which is used for the KO Drum Interlock I-951 (see Interlock I-951 below). Overhead vapor flow from the Liquids Knock Out Drum to the Seal Drum, D-952 is indicated on FI-953. The liquid level on the left side of the Seal Drum is indicated on LI-953. Utility water supply is controlled by FIC-961 which manipulates valve FV-961. The right side of the seal drum is liquid level controlled by LIC-952 which adjusts LV-952. The flow of seal water from the Seal Drum, D-952, is measured by FI-952. Switches HS-952A and HS-952B are used to change the state of the motor for the Seal Water Pumps, P-952A and P-952B, respectively. The flare system has a pilot generator, X-955, which is turned on and off with switch HS-955. The flow of pilot fuel gas to X-955 is shown on FI-955. XI-955 is a measure of pilot flame intensity. Flare gas is supplemented with a small stream of fuel gas which is under flow control by FIC-954 which adjusts the valve opening of FV-954. XI-956 provides an indication of flame intensity in the Flare Stack. TI-955A and TI-955B are indicators for temperatures in the Flare Stack, FS-952.

Interlock I-401

Refer to Schematic 5 and Schematic 6 in the “Process Schematics” section above. This interlock protects the Distillation Column T-401 in case of high pressure and protects the Reflux Drum D-401 from overfilling by stopping hot oil flow to the Distillation Column Reboiler, E-402. The interlock is activated by either of the following:

- the pressure of T-401 exceeds15.0 BARG as indicated on PAH-403

- the liquid level of D-401 exceeds 90% as indicated on LAH-412 This interlock has the following effects:

- E-402 hot oil flow controller FIC-004 is locked in manual and its output is locked at 0%

- XA-401 will alarm I-401 automatically resets when all the trip inputs have cleared. The flow of hot oil to E-402 must be reestablished manually.




Instrumentation, continued Interlock I-951

Refer to Schematic 8 in the “Process Schematics” section above. This interlock protects the Liquids Knock Out Drum D-951 from being overfilled during a release to the Flare Header. The interlock is activated by:

- the level of D-951 exceeds 30% (high trip) as indicated on LAH-951 - the level of D-951 exceeds 60% (high-high trip) as indicated on LAH-951

This interlock has the following effects:

- On a high trip pump P-951A will be started on a one-shot basis - On a high trip LIC-951 will be placed in automatic mode with a setpoint of

40% on a one-shot basis - On a high-high trip pump P-951B will be started on a one-shot basis

I-951 only executes on a one-shot basis to assist the operator during an emergency. At any time thereafter, the operator may start/stop either pump with HS-951A/B and adjust LIC-951 as needed to manage the situation. Each trip input (high and high-high) will be is re-armed once the level is below the trip point (30% and 60%, respectively).

Normal Design Conditions

The following table is a list of the normal design conditions (initial condition 1) for the SPM-720721 Advanced Distillation simulation as provided by Simtronics.

Analog Instruments

TagID Description Value Units Output % AI-400A PROPANE FEED 1.3 MOLE% AI-400B BUTANE FEED 65.1 MOLE% AI-400C PENTANE FEED 21.8 MOLE% AI-400D HEXANE FEED 11.8 MOLE% AI-411 BUTANE T401 BTM 0.82 MOLE% AI-414 PENTANE IN BUTAN 0.24 MOLE% FI-100 UNIT A FLOW 310 M3/D 42.2 FI-412 D-401 TO FLARE 0 KNM3D FI-901 LT XFER UNIT C 184.9 M3/D FI-902 HVY XFER UNIT E 125 M3/D FI-903 OFFSPEC XFER 0 M3/D FI-951 LIQ TO DISPOSAL 0 M3/D FI-952 WATER TO DISPOSAL 27 M3/D FI-953 FLARE GAS 5.3 KNM3D FI-955 FUEL GAS TO PILOT 0.4 KNM3D FI-960 N2 PURGE TO FLARE 5.3 KNM3D FIC-004 E-402 HOT OIL 1343.3 M3/D 52.4 FIC-400 FEED TO T-401 310 M3/D 38.6 FIC-411 T-401BTM TO STG. 125.1 M3/D 49.7 FIC-413 REFLUX TO T-401 222.6 M3/D 52.7 FIC-414 BUTANE TO STG. 184.9 M3/D 60.8




Analog Instruments

TagID Description Value Units Output % FIC-414 BUTANE TO STG. 184.9 M3/D 60.8 FIC-954 FUEL GAS TO FLARE 5.38 KNM3D 30 FIC-961 SEAL WATER 27 M3/D 40.3 HIC-024 E-401 CW 70 % 70 HIC-025 E-403 CW 60 % 60 HIC-026 E-404 CW 70 % 70 HIC-415 E-400 BTMS IN 100 % 100 HIC-960 N2 PURGE TO FLARE 40 % 40 LAH-412 D-401 HH TRIP 50 % LAH-951 D-951 HI TRIP 0 % LAHH-951 D-951 HI-HI 0 % LI-953 SEAL WATER 100 % LIC-101 V-101 TANK 50 % 62 LIC-411 T-401 BOTTOM 50 % 41.7 LIC-412 D-401 OVERHEAD 50 % 61.6 LIC-901 V-901 TANK 50 % 23.3 LIC-902 V-902 TANK 50 % 69.4 LIC-903 V-903 TANK 50.4 % 0 LIC-951 D-951 KO DRUM 0 % 0 LIC-952 D-952 SEAL DRM 50 % 36 PAH-403 T-401 HH TRIP 8.99 BARG PDI-401 T-401 TOP 133.3 MBAR PDI-402 T-401 BOTTOM 138.8 MBAR PI-001 HOT OIL SUPPLY 8.99 BARG PI-021 CW SUPPLY 3.45 BARG PI-101 V-101 TANK 0.87 BARG PI-400 FEED TO E-400 17.9 BARG PI-403 T-401 TOP 8.99 BARG PI-903 FEED HEADER 0 BARG PI-911 V-901 TANK 1.77 BARG PI-912 V-902 TANK 0 BARG PI-913 V-902 TANK 0 BARG PI-951 D-951 KO DRUM 0.01 BARG PIC-412 D-401 OVERHEAD 8.69 BARG 50 PIC-413 D-401 TO FLARE 8.69 BARG 0 TI-001 HOT OIL SUPPLY 260 DEG C TI-004 E-402 H.O. OUT 206.9 DEG C TI-021 CW SUPPLY 26.7 DEG C TI-024 E-401 CW OUTLET 44.3 DEG C TI-025 E-403 CW OUTLET 26.7 DEG C TI-026 E-404 CW OUTLET 27.5 DEG C




Analog Instruments

TagID Description Value Units Output % TI-026 E-404 CW OUTLET 27.5 DEG C TI-400 FEED TO T-401 25 DEG C TI-402 T-401 FEED 67.7 DEG C TI-403 T-401 OVERHEAD 78.8 DEG C TI-404 T-401 TRAY 32 79.7 DEG C TI-405 T-401 TRAY 28 81.4 DEG C TI-406 T-401 TRAY 18 88.3 DEG C TI-407 T-401 TRAY 12 98.7 DEG C TI-409 E-402 NGL IN 130.5 DEG C TI-410 E-402 NGL OUT 135.9 DEG C TI-411 T-401 BOTTOM 132.1 DEG C TI-412 E-401 OUTLET 33.2 DEG C TI-413 D-401 LIQUID 33.1 DEG C TI-415 E-400 BOTTOMS 26 DEG C TI-416 E-403 INLET 26 DEG C TI-417 E-403 TO STORAGE 26 DEG C TI-418 BUTANE TO STORG 27.7 DEG C TI-955A FLARE STACK 413.3 DEG C TI-955B FLARE STACK 413.3 DEG C TIC-408 T-401 TRAY 6 121.1 DEG C 44.8 XI-955 PILOT INTENSTY 54.7 % XI-956 FLARE INTENSTY 8.2 %





Switches TagID Description State HS-400A P-400A MOTOR RUN HS-400B P-400B MOTOR STOP HS-401A P-401A MOTOR RUN HS-401B P-401B MOTOR STOP HS-901 LIGHT PUMP RUN HS-902 HEAVY PUMP RUN HS-903 OFF-SPEC PUMP STOP HS-951A P-951A MOTOR STOP HS-951B P-951B MOTOR STOP HS-952A P-952A MOTOR RUN HS-952B P-952B MOTOR STOP HS-955 PILOT GENERATR RUN XV-101A V-101 UNIT A OPEN XV-101B V-101 BYPASS CLSD XV-101C V-101 BOTTOMS CLSD XV-101D V-101 OFF-SPEC CLSD XV-901 OVERHEAD TO V-901 OPEN XV-902 BOTTOMS TO V-902 OPEN XV-903A OVERHEAD TO V-903 CLSD XV-903B BOTTOMS TO V-903 CLSD XV-903C OFF-SPEC UNIT D CLSD





Normal Production Monitoring

Below are the major process variables to be polled. The other process variables should be periodically polled to ensure normal process operation.

TagID Description Value Units AI-411 BUTANE T401 BTM 0.82 MOLE% AI-414 PENTANE IN BUTAN 0.24 MOLE% FI-100 UNIT A FLOW 1950 BPD FI-412 D-401 TO FLARE 0 MMCFD FI-901 LT XFER UNIT C 1163 BPD FI-902 HVY XFER UNIT E 787 BPD FI-952 WATER TO DISPOSAL 169.8 BPD FI-953 FLARE GAS 0.19 MMCFD FI-960 N2 PURGE TO FLARE 0.188 MMCFD FIC-004 E-402 HOT OIL 8449 BPD FIC-400 FEED TO T-401 1950 BPD FIC-411 T-401BTM TO STG. 787 BPD FIC-413 REFLUX TO T-401 1400 BPD FIC-414 BUTANE TO STG. 1163 BPD FIC-954 FUEL GAS TO FLARE 0.19 MMCFD FIC-961 SEAL WATER 169.8 BPD LAH-412 D-401 HH TRIP 50 % LAH-951 D-951 HI TRIP 0 % LI-953 SEAL WATER 100 % LIC-101 V-101 TANK 50 % LIC-411 T-401 BOTTOM 50 % LIC-412 D-401 OVERHEAD 50 % LIC-901 V-901 TANK 50 % LIC-902 V-902 TANK 50 % LIC-903 V-903 TANK 50.4 % LIC-951 D-951 KO DRUM 0 % LIC-952 D-952 SEAL DRM 50 % PAH-403 T-401 HH TRIP 130.4 PSIG PDI-401 T-401 TOP 53.5 INH2O PDI-402 T-401 BOTTOM 55.7 INH2O PI-001 HOT OIL SUPPLY 130.3 PSIG PI-021 CW SUPPLY 50 PSIG PI-101 V-101 TANK 12.6 PSIG PI-400 FEED TO E-400 259.4 PSIG PI-403 T-401 TOP 130.4 PSIG






TagID Description Value Units AI-411 BUTANE T401 BTM 0.82 MOLE% AI-414 PENTANE IN BUTAN 0.24 MOLE% FI-100 UNIT A FLOW 310 M3/D FI-412 D-401 TO FLARE 0 KNM3D FI-901 LT XFER UNIT C 184.9 M3/D FI-902 HVY XFER UNIT E 125 M3/D FI-952 WATER TO DISPOSAL 27 M3/D FI-953 FLARE GAS 5.3 KNM3D FI-955 FUEL GAS TO PILOT 0.4 KNM3D FI-960 N2 PURGE TO FLARE 5.3 KNM3D FIC-004 E-402 HOT OIL 1343.3 M3/D FIC-400 FEED TO T-401 310 M3/D FIC-411 T-401BTM TO STG. 125.1 M3/D FIC-413 REFLUX TO T-401 222.6 M3/D FIC-414 BUTANE TO STG. 184.9 M3/D FIC-954 FUEL GAS TO FLARE 5.38 KNM3D FIC-961 SEAL WATER 27 M3/D LAH-412 D-401 HH TRIP 50 % LAH-951 D-951 HI TRIP 0 % LI-953 SEAL WATER 100 % LIC-101 V-101 TANK 50 % LIC-411 T-401 BOTTOM 50 % LIC-412 D-401 OVERHEAD 50 % LIC-901 V-901 TANK 50 % LIC-902 V-902 TANK 50 % LIC-903 V-903 TANK 50.4 % LIC-951 D-951 KO DRUM 0 % LIC-952 D-952 SEAL DRM 50 % PAH-403 T-401 HH TRIP 8.99 BARG PDI-401 T-401 TOP 133.3 MBAR PDI-402 T-401 BOTTOM 138.8 MBAR PI-001 HOT OIL SUPPLY 8.99 BARG PI-021 CW SUPPLY 3.45 BARG PI-101 V-101 TANK 0.87 BARG PI-400 FEED TO E-400 17.9 BARG PI-403 T-401 TOP 8.99 BARG






TagID Description Value Units PI-911 V-901 TANK 1.77 BARG PI-912 V-902 TANK 0 BARG PI-913 V-902 TANK 0 BARG PI-951 D-951 KO DRUM 0.01 BARG PIC-412 D-401 OVERHEAD 8.69 BARG TI-001 HOT OIL SUPPLY 260 DEG C TI-021 CW SUPPLY 26.7 DEG C TI-400 FEED TO T-401 25 DEG C TI-402 T-401 FEED 67.7 DEG C TI-403 T-401 OVERHEAD 78.8 DEG C TI-411 T-401 BOTTOM 132.1 DEG C TI-412 E-401 OUTLET 33.2 DEG C TI-417 E-403 TO STORAGE 26 DEG C TI-418 BUTANE TO STORG 27.7 DEG C TI-955A FLARE STACK 413.3 DEG C TI-955B FLARE STACK 413.3 DEG C TIC-408 T-401 TRAY 6 121.1 DEG C XI-955 PILOT INTENSTY 54.7 % XI-956 FLARE INTENSTY 8.2 %





Monitoring and Adjusting Advanced Distillation Operations

The main objective of Advanced Distillation operations is maintaining throughput while safely operating the unit. Safe operations are:

- Keeping all controlled liquid levels around 50% - Making sure equipment is not operated at higher temperatures and

pressures than for which they were designed - Minimizing flaring of gas from the Distillation Column and the Reflux Drum - Keeping the light and heavy products on-specification

Alarms will sound to alert the operator to potentially unsafe conditions. The operator needs to develop an understanding of the Distillation Column and Tank Farm with Flare System so he can determine the cause of such alarms. Often, it is possible for skilled operators to discover problems and take remedial action before an alarm occurs. Disturbances in feed supply conditions such as composition will cause the largest changes in operating conditions of the Unit. When this happens, check that levels throughout the unit are properly maintained. If the levels cannot be maintained because of control valve/piping capacity, reduce feed rate until the levels are back in control. Keeping product purities on-target after significant feed composition changes will often require adjustment of column operating pressure, bottoms temperature and reflux flow rate. It is important to recognize in distillation processes that temperatures in columns are indicative of the composition at the point of measurement. Higher temperatures represent heavier composition and vice-versa. Also, it is important to understand that the column pressure will also affect the indicated temperature for a given composition. Higher pressures will increase column temperatures and vice-versa. Therefore, when changing a column pressure, the bottoms temperature controller setpoint will also need to be adjusted. Use the bottoms composition analyzer to guide the temperature controller setpoint changes. Make all setpoint changes gradually and stay vigilant to notice any operating difficulties. For overhead product purity control, adjust the reflux flow to the column to get the product purity specification back to the desired value. Increasing reflux flow will improve the overhead product purity and vice-versa. However, increasing reflux flow comes at the expense of higher utility cost because more hot oil must be used to maintain the bottoms temperature. Also, very high reflux rates may cause choking or flooding in the column. Be careful to monitor distillation section pressure drops and keep them out of alarm. If product purity cannot be maintained through reflux flow control due high column pressure drop, then consider reducing feed rate to the Distillation Column until the purity specification can be met while keeping the column section pressure drops out of alarm. Another adjustment that might be necessary as conditions change is the setpoint of the pressure controller, PIC-412, of the Reflux Drum, D-401. If this pressure is too low, too much heavy components will move to the top of the Distillation Column. This can lead to off-spec conditions for the product butane. Conversely, if the setpoint of PIC-412 is too high, additional butane will be condensed, leading to product purity issues at the bottom of the Distillation Column.




Monitoring and Adjusting Advanced Distillation Operations

Keeping delivered products on-specification is a very important economic requirement. If the composition of light or bottom products become off-specification, switch the affected product’s flow to the Off-Spec Tank, V-903, until the problem is resolved. The off-spec material in V-903 can be recycled to the Feed Tank, V-101, at a later time. When recycling off-spec products, use a low flow rate to avoid upsetting the Distillation Column by manually adjusting the output of the Off-Spec Tank’s level controller. The flare system normally needs no special attention until there is a release. The most dangerous safety issue would be overfilling of the Feed Tank, V-101, with a subsequent release of liquids into the Flare Header. This flow may exceed the capacity of the Liquid Knock Out Pumps P-951A/B. If this occurs, immediately block any flows into the tank. The same rule applies to the three other tanks, but the flow rates to these tanks are less than the normal feed rate to the Advanced Distillation Plant.

Responding to Alarms

An instrument in alarm indicates that there is an upset condition in the process. A swift response to an alarm can prevent a dangerous condition from occurring. Responding directly to a key process variable that is in alarm may not always be the best corrective action. Understanding and observing the relationships of all process variables can help troubleshoot the problem and take proper corrective action to return the process to design conditions.




Pre-Startup

Pre-Startup Procedure

Pre-startup procedures must be performed before any startup may begin.

Normal Pre-Startup Procedure

All Simtronics process simulations assume that the following normal procedures have already been completed. However, trainees should be made aware of these procedures and any other procedures particular to your process plant. SPM-: Normal Pre-Startup Procedure • Notify all personnel involved with the startup: − Shift Supervisors − Process Engineers − Control Engineers − Outside Operators − Instrument Technicians

• Flush, clean, and purge all lines • Flush, clean, and purge all equipment • Pressure test all lines • Pressure test all equipment • Check, calibrate, and zero all instruments • Commission all pumps • Commission all heat exchangers • Commission any other process equipment as required

Cold Start Pre-Startup Procedure

The cold start initial condition provided by Simtronics ensures that the following procedures have already been completed. However, trainees should be required to perform these procedures as a matter of course. You may change the cold start initial condition provided by Simtronics to ensure that trainees do in fact perform these procedures.

SPM-: Cold Start Pre-Startup Procedure • Check position of all block valves (open or closed) • Check position of all control valves (open or closed) • Check status of all controllers (manual, automatic, or cascade) • Check status of all switches (on or off) • Check status of all pumps (run or stop) • Check status of any other equipment or instrumentation as required




Startup

Startup Procedure Overview

The following is a startup procedure recommended by Simtronics. You may modify this procedure to more closely reflect your particular plant startup procedure. On the Advanced Distillation simulator, the startup procedure consists of the following main steps:

1. Line up controllers 2. Start cooling water to coolers 3. Commission Flare System 4. Bring in feed 5. Start hot oil to Distillation Column 6. Establish Distillation Column reflux 7. Commission Storage Tanks 8. Bring unit up to design rate

The entire startup procedure is practiced from initial condition no. 2 – COLD START. In this initial condition, all equipment is at ambient temperature and pressure. It should take about 2 to 3 hours to complete the startup procedure of the Advanced Distillation process.

Startup Procedure

This section provides the detailed startup procedure for the Advanced Distillation process. If there are any unusual troubles noticed during startup, take time to identify and correct any problems before proceeding to the next step. If it is not possible to resolve a critical problem, it may be necessary to shut the unit down.

Check Step Action Time To

Complete Step, Minutes

1 Line up the following controllers: Place PIC-412, Reflux Drum D-401 to flare pressure controller, into automatic. Verify setpoint is 8.7 BARG. Place PIC-413, Reflux Drum D-401 to flare pressure controller, into automatic. Verify setpoint is 11.0 BARG.

1

2 Place all cooling water into service by adjusting the following HICs:

- HIC-025, E-403 Bottoms Cooler to 60%

- HIC-024, E-401 Condenser to 70% - HIC-026, E-404 Overhead Cooler to

70%

1





3 Start nitrogen purge to the Flare Header by opening the output of HIC-960 to 40%. Verify nitrogen is flowing by observing FI-960.

1

4 Commission the Liquids Knock Out Drum D-951 level controller. Do not start either Knock Out Liquids pump P-951A/B at this time. These are only started if a liquid accumulates in D-951.

- Place LIC-951 in automatic - Adjust LIC-951 setpoint to 50%

1

5 Set up Seal Drum, D-952 in Flare System

- Place Utility Water flow controller, FIC-961 in automatic

- Change FIC-961 setpoint to 27.0 M3/D

- Place D-952 Level controller in automatic

- Change LIC-952 setpoint to 50.0% - After a couple minutes the seal side

of the D-952 should be filled as seen on LI-953 and water will be spilling over the baffle to the collection side. After the level indicated on LIC-952 is above 20%, start Seal Water Pump P-952A by setting HS-952A to run.

2

6 Set up the Flare System so that flare gas will burn and warm up the Flare Stack FS-952.

- Set Flame Generator X-955 start/stop switch HS-955 to run. Verify that fuel gas is flowing as indicated on FI-955. Also verify good flame intensity reading on XI-955.

- Place fuel gas flow controller FIC-954 in automatic.

- Enter a setpoint for FIC-954 of 5.38 KNM3/D.

1

7 Bring in feed by first inventorying the Feed Tank, V-101, to about 30%. This will provide a good working inventory of fresh feed while maintaining enough ullage (spare volume) in V-101 to accommodate recycle from Off-Spec Tank V-903.

- Open XV-101A and watch as level

1





builds in V-101 using LIC-101.

8 As LIC-101 approaches 50%, prepare downstream pumps and valves.

- Place FIC-400 in manual. Set the output of FIC-400 to 5%.

- Start P-400A with HS-400A. This will begin moving feed from Feed Tank, V-101 to Distillation Column T-401. Verify feed is moving into Distillation Column T-401 and starts filling the bottom.

3

9 Prepare Overhead System to handle condensate.

- Place FIC-414 (for light product to V-901, Light Product Storage Tank) in cascade.

- Place LIC-412, the level controller for the Reflux Drum, D-401, in automatic with a setpoint of 50%.

-

1

10 Prepare Distillation Column Bottoms to handle liquid.

- Place FIC-411 (for pentane product to V-902, Heavy Product Storage Tank) in cascade.

- Place LIC-411, the level controller for the Distillation Column, T-401 in automatic with a setpoint of 50%.

1

11 After Feed Tank V-101 is filled to around 50%, bypass the tank and feed directly to the Distillation Column:

- Open XV-101B - Close XV-101A - Stop feed pump P-400A using

HS-400A The feed rate from Unit A will now be controlled by FIC-400 in this configuration.

1

12 Line up top and bottom products to the Off-Spec Tank V-903:

- Open XV-903A - Open XV-903B - Close XV-901

1





- Close XV-902

13 Prepare Heavy Product Tank to handle liquid. Set Heavy Product Tank Level Controller (LIC-902) in automatic with a setpoint of 50%.

1

14 Prepare Light Product Tank to handle liquid. Set Heavy Product Tank Level Controller (LIC-901) in automatic with a setpoint of 50%.

1

15 Start heating up the Distillation Column using the reboiler.

- Place the Distillation Column (T-401) bottoms temperature controller, TIC-408 in manual.

- Place the hot oil flow controller, FIC-004 in automatic.

- FIC-004 setpoint to 225 M3/D. - Preheat feed by opening HIC-415 to

15%. As the bottom of the column warms up it will begin generating overhead vapors and T-401 pressure will increase more quickly. This will start pushing bottoms out of T-401 into the Off-Spec Tank V-903. Verify the bottoms level LIC-411 is controlled by FIC-411.

4

16 Gradually ramp up the process as follows:

- With FIC-400 in automatic, change setpoint to 100 M3/D

- FIC-004 setpoint = 450 M3/D - HIC-415 output = 30% -

4

17 When the level of the Reflux Drum D-401 reaches 30%, start refluxing the Distillation Column:

- Start Reflux Pump P-401A by placing HS-401A in the RUN position

- Place FIC-413 in automatic and adjust its setpoint to 50 M3/D

4

18 Place Reboiler E-402 in automatic mode:

- Place FIC-004 in cascade - Place TIC-408 in automatic - Change TIC-408 setpoint to 110.0

1





DEG C

19 Continue to ramp up feed rate:

- FIC-413 setpoint = 100 M3/D - HIC-415 output = 45 % - TIC-408 setpoint = 112.0 DEG C

4


- FIC-413 setpoint = 150 M3/D - FIC-400 setpoint = 200 M3/D - HIC-415 output = 60%

4


- FIC-413 setpoint = 200 M3/D - FIC-400 setpoint = 250 M3/D - HIC-415 output = 75 % - TIC-408 setpoint = 114.0 DEG C

4


- FIC-413 setpoint = 223 M3/D - FIC-400 setpoint = 300 M3/D - HIC-415 output = 100 % - TIC-408 setpoint = 116.0 DEG C

4

23 As the level of Off-Spec Tank V-903 approaches 75%, start recycling its contents back to the Feed Tank V-101. Before recycling, make sure that the level of V-101 can accommodate recycle flow (LIC-101 should be around 30%).

- Open XV-101D - Close XV-903C - Place LIC-903 into automatic with a

setpoint of 75% - Start Off-Spec Pump P-903 by

placing HS-903 into the RUN position

1

24 Switch feed from direct feed mode to the Feed Storage Tank. Then start the Feed Pump P-400A. Set the feed rate to design:

- Open XV-101A - Set switch HS-400A to RUN - Close XV-101B - FIC-400 setpoint = 310.0 M3/D

5





25 If the level of Feed Tank V-101 (LIC-101) is reasonably close to 50%, place FIC-400 into cascade mode. Then place LIC-101 into automatic with a setpoint of 50%. If LIC-101 is much higher than 50%, first increase the setpoint of FIC-400 to about 5% higher than design until the level gets reasonably close to 50% before establishing the cascade between LIC-101 and FIC-101. If LIC-101 is much lower than 50%, first decrease the setpoint of FIC-400 to about 5% lower than design until the level gets reasonably close to 50% before establishing the cascade between LIC-101 and FIC-101.

2

25 Adjust the Distillation Column temperature controller TIC-408 setpoint to 118.0 DEG C.

1

26 Once the light product specification (analyzer AI-414) is out of alarm, switch the routing of light overhead product from the Off-Spec Tank V-903 to the Light Product Tank V-901:

- Open XV-901 - Close XV-903A

Verify the Light Product Tank level LIC-901 starts increasing.

10

27 Once the heavy product specification (analyzer AI-411) is out of alarm, switch the routing of heavy bottoms product from Off-Spec Tank V-903 to Heavy Product Tank V-902:

- Open XV-902 - Close XV-903B

Verify the Heavy Product Tank level LIC-902 starts increasing.

1

28 Increase Distillation Column bottom temperature controller TIC-408 setpoint to design value of 121.1 DEG C.

1

29 After Off-Spec Tank V-903 is no longer receiving material, the recycle flow to Feed Tank V-101 will gradually drop to zero. Manually reduce the level of V-903 to 50%

10





by placing LIC-903 into manual with an output of 10%.

30 Once the Light Product Tank level LIC-901 approaches 50%, start shipping light product to battery limits by starting Light Product Pump P-901 using switch HS-901. Verify flow on FI-901 and level control.

2

31 Once Heavy Product Tank level LIC-902 approaches 50%, start shipping heavy product to battery limits by starting Bottom Product Pump P-902 using switch HS-902. Verify flow on FI-902 and level control.

2

32 Once Off-Spec Tank level LIC-903 is at or below 50%, stop Off-Spec Transfer Pump P-903 by placing HS-903 in the STOP state. Secure the line by adjusting the output of LIC-903 to 0% and closing XV-101D. Also make sure XV-903C is closed.

15

33 Continue to monitor the unit as the conditions trend toward design. Verify all controllers and switches are in their proper mode and state and that setpoints of controllers are at their design values. Startup is complete.

15



Shutdown

Normal Shutdown Procedure Overview

The following is a shutdown procedure recommended by Simtronics. You may modify this procedure to more closely reflect your particular process plant shutdown procedures. This orderly shutdown procedure should take approximately 2 to 3 hours. This procedure is practiced from initial condition no. 1 – DESIGN. In this initial condition the Advanced Distillation process is operating at steady-state design conditions. The normal shutdown procedure involves the following main steps:

1. Reduce feed rate to 50% 2. Stop feed and hot oil flows 3. Lower liquid levels while maintaining pressure 4. Slowly de-pressure the unit 5. Stop the Flare System 6. Isolate the unit

It should take about 2 to 3 hours to shut down the Advanced Distillation process.

Normal Shutdown Procedure

This section provides the detailed shutdown procedure for the Advanced Distillation process. If there are any unusual troubles noticed during shutdown, take time to identify and correct any problems before proceeding to the next step.

Check Step Action

Time To Complete

Step, Minutes

1 Switch over to direct feed (bypassing the Feed Tank, V-101)

- Close XV-101A - Open XV-101B

1

2 Over twenty minutes, gradually reduce feed to approximately 50% operation, making a setpoint change ~ once every 5 minutes:

- Place FIC-400 in automatic - FIC-400 setpoint = 250.0 M3/D - FIC-400 setpoint = 225.0 M3/D - FIC-400 setpoint = 200.0 M3/D - FIC-400 setpoint = 175.0 M3/D - FIC-400 setpoint = 150.0 M3/D

25

3 Once the Feed Tank (V-101) is empty, stop the Distillation Feed Pump, P-400A, by switching HS-400A to stop.

1




Complete Step,

Minutes 4 Continue turning down feed via FIC-400 by

reducing its setpoint ~ once every 5 minutes:

- FIC-400 setpoint = 125.0 M3/D - FIC-400 setpoint = 100.0 M3/D - FIC-400 setpoint = 75.0 M3/D - FIC-400 setpoint = 50.0 M3/D

15

5 Gradually reduce the setpoints of the level controllers for Reflux Drum D-401 and the bottom of Distillation Column T-401 from 50% to 20% over 10 minutes:

- D-401 – LIC-412 - T-401 – LIC-411

10

6 While reducing the levels per step 5 above, stop feed to the Distillation Column:

- Place FIC-400 into manual with an output of 0%

- Close XV-101B to isolate the plant from Unit A

1

7 Switch light and heavy products from their respective storage tank to the Off-Spec Tank:

- Open XV-903A - Open XV-903B - Close XV-901 - Close XV-902

1

8 Gradually shut down Distillation Column Reboiler, E-402 by reducing its setpoint of the hot oil flow controller twice over 10 minutes:

- Place FIC-004 in automatic - FIC-004 setpoint = 500.0 M3/D - FIC-004 setpoint = 300.0 M3/D

10

9 After a few minutes, stop Reboiler E-401 hot oil flow by placing flow controller FIC-004 into manual with an output of 0%.

3

10 When Reflux Drum D-401 (LIC-412) is nearly empty, stop Reflux Pump P-401A by switching HS-401A to STOP.

3

11 Place reflux flow controller into manual with an output of 0%.

1




Complete Step,

Minutes 12 Stop the flow to the Distillation Column Feed

Preheater (E-400) by closing HIC-415. Drain remaining liquid from the bottom of the Distillation Column (T-401):

- HIC-415 output = 0% - Place FIC-411 to manual with an output of

30%

1

13 De-pressure the Reflux Drum (D-401) and Distillation Column (T-401).

- Place PIC-412 to manual - Adjust PIC-412 output to 100%

1

14 When the bottom level of the Distillation Column becomes 0%, adjust the output of bottoms flow controller FIC-411 to 0%.

10

15 Once the level of the Reflux Drum stops increasing as the Distillation Column de-pressures, manually transfer the liquid to Off-Spec Tank V-903:

- Place FIC-414 in manual with an output of 20%

- Start Reflux Pump P-401A by placing HS-401A in the RUN position

- Place LIC-412 in manual Once the level becomes 0%:

- Stop P-401A by placing HS-401A in the STOP position

- Adjust the output of FIC-414 to 0%

5

16 Empty Heavy Product Tank, V-902 to Unit E.

- LIC-902 to manual - LIC-902 output = 100%

Continue to the next step but monitor the levels in the tank farm.

1




Complete Step,

Minutes 17 Transfer the inventory of Off-Spec Tank V-903 to

Unit D:

- Open XV-903C - Start P-903 by placing HS-903 in the RUN

position - LIC-903 to manual - LIC-903 output = 100%

Continue to the next step, but monitor the levels in the tank farm.

1

18 Empty Light Product Tank, V-901 to Unit C.

- LIC-901 to manual - LIC-901 output = 100%

Continue to the next step, but monitor the levels in the tank farm.

1

19 When the level of any tank in the tank farm approaches 0%, stop the respective pump and isolate the shipping line by adjusting output of the respective level controller to 0%:

- V-901: HS-901/LIC-901 - V-902: HS-902/LIC-902 - V-903: HS-903/LIC-903

Continue to the next step while monitoring tank farm levels.

30

20 Start draining the collection side of Seal Drum D-952 by placing LIC-952 into manual and increasing its output to 60%.

1

21 Once the Off-Spec Tank is empty and P-903 has been stopped, isolate the tank:

- Close XV-903A - Close XV-903B - Close XV-903C

1

22 Stop fuel gas to Flare System by placing FIC-954 to manual with an output of 0%.

1

23 Stop the Pilot Flame Generator X-955 by placing HS-955 in the STOP position.

1




Complete Step,

Minutes 24 Stop utility water flow to Seal Drum D-952 by

placing FIC-961 into manual with an output of 0%. The seal side of the drum will slowly drain into the collection side of the drum through the slot on the bottom of dividing baffle.

1

25 Reduce the flow of water from Seal Drum D-952 by adjusting the output of LIC-952 as needed to maintain a level on the collection side of D-952 while the seal side drains. When the seal side level LI-953 is nearly 0%, stop Seal Water Pump P-952A by placing HS-952A in the STOP state. Adjust the output of LIC-952 to 0%.

20

26 Isolate the unit completely by adjusting the outputs of the following controllers to 0% (place the controllers in manual as needed):

- HIC-024 (E-401 condenser cooling water) - HIC-025 (E-403 bottoms cooling water) - HIC-026 (E-404 overhead cooling water) - HIC-960 (Nitrogen to Flare Header) - PIC-413 (D-401 safety vent) - LIC-951 (D-951 liquids level)

Also adjust the output of PIC-412 (D-401 pressure controller) to 50%. This will close both PV-412A and PV-412B.

5

27 Verify the unit is cooling and is de-pressured and that all levels are at minimum and that all flows have stopped. Normal shutdown is complete.

5



Emergency Operations

Emergency Operation Procedure

All emergencies should be handled quickly. The particular steps taken in an emergency are specific to the problem at hand. As always, your trainees should follow the emergency procedures particular to your process plant. If an emergency cannot be handled quickly, then an emergency shutdown should be performed.

Emergency Shutdown Procedure

The following is an emergency shutdown procedure recommended by Simtronics. You may modify this procedure to more closely reflect your particular process plant emergency shutdown procedures. The procedure given here assumes all equipment and systems are in service as in initial condition no. 1 – DESIGN. The main objective in an emergency shutdown is to quickly isolate the unit and de-energize all rotating equipment. It is not recommended to de-pressure the unit unless the unit can first be de-inventoried of liquids in order to prevent chilling of the unit due to flashing. The following main steps are taken to isolate the unit:

1. Stop feed to the unit 2. Stop hot oil to the reboiler 3. Stop all pump motors 4. Isolate the Distillation Column 5. Verify the unit is stable

After an emergency stop the unit can be restarted if needed. It should take about 10 minutes to do an emergency shutdown of the Advanced Distillation process.

Check Step Action

Time To Complete

Step, Minutes

1 Stop feed to the Unit:

- Place FIC-400 into manual with an output of 0%

- Stop feed pump P-400A by placing HS-400A into the STOP state

- Isolate the feed from Unit A by closing XV-101A

1

2 Stop hot oil to the reboiler, E-402, by placing the hot oil flow controller FIC-004 in manual with an output of 0%.

1

3 Stop the motor of Reflux Pump P-401A by placing hand switch HS-401A into the STOP position.

1




Complete Step,

Minutes 4 Isolate the Distillation Column by the placing the

following controllers into manual with an output of 0%:

- FIC-413 (Reflux) - FIC-414 (Light Product) - FIC-411 (Distillation Column Bottoms

Product)

1

5 Stop all operating pumps in the Tank Farm:

- P-901 (HS-901 to STOP) - P-902 (HS-902 to STOP)

Place tank farm level controllers into manual with an output of 0%:

- LIC-901 (V-901) - LIC-902 (V-902) - LIC-903 (V-903)

2

6 The Flare System is kept in operation to handle the safe discharge of any releases to the Flare Header during an emergency.

0

7 Verify all flows except for the Flare System flows have stopped and that pressures and levels are holding steady. The unit may now be de-inventoried and de-pressured or restarted, depending on the circumstances. Emergency shutdown is complete.

5



Profitability Calculations

Overview

The Advanced Distillation simulator includes a set of profitability calculations to illustrate the basic economics of running a continuous industrial process. The calculations are illustrated on Schematic 21 shown in the Process Schematics section. The instructor can adjust the cost of each entity in the calculations using faults 173 through 181. These faults only affect the profitability calculations. The instant profit is shown on the Schematic 2 – Overview.



Critical Safety Performance

Overview

The Advanced Distillation simulator includes a critical safety performance monitoring schematic to help the student understand the most critical operating parameters of the Advanced Distillation Process. These are shown on Schematic 22 – Critical Safety Performance shown in the Process Schematics section. The critical operating variables for each of the major equipment in the process are shown on Schematic 22. A safety penalty is calculated whenever a condition exceeds its high or low alarm settings. The penalty amount is the absolute value of the deviation of the PV from the alarm setting expressed as a percent of instrument range. A total sum of the penalties is also shown on Schematic 2 – Overview. If the total penalty becomes non-zero, an alarm will be generated in addition to the PV alarm that first causes the penalty sum to become non-zero. Schematic 22 also shows if the high and low PV monitoring for variables is active. In some circumstances, the monitoring for a critical safety alarm becomes disabled because the process conditions are not critical. For example, a low level alarm on a vessel that supplies an operating pump will generate a safety penalty. However, if no pumps are operating, then low level is not critical and no penalty is generated. If, then, a pump is started with a low level in the supply vessel, a safety penalty will be calculated. One of the main objectives of simulator training is for the student to avoid and eliminate all critical safety penalties in a safe, efficient manner; the penalty sum is a guide to the progress of attaining safer operation. The conditions under which the safety penalties are calculated are provided below:

Equipment Tag High PV Enabled Conditions

Low PV Enabled Conditions

V-101 LIC-101 Always P-400A or B running PI-101 Always Never

T-401 LIC-411 Always FIC-411 output > 0% PI-403 Always Never

E-403 TI-417 Always Never E-401 TI-412 Always Never D-401 LIC-412 Always P-401A or B running

PIC-412 Always Never E-404 TI-418 Always Never V-901 LIC-901 Always P-901 running

PI-911 Always Never V-902 LIC-902 Always P-902 running

PI-912 Always Never V-903 LIC-903 Always P-903 running

PI-913 Always Never D-951 LAHH-951 Always P-951A or B running

FI-960 Never Always D-952 LI-953 Never Always

LIC-952 Always P-952A or B running FS-952 XI-955 Never Always



Virtual Field Operator

Overview

The Simtronics Virtual Field Operator (VFO) is an optional software module which presents a realistic walk-about interface to provide advanced process operations training for field operators. With a VFO station, the console DCS operator can coordinate with one or more field operators to perform very realistic startup, shutdown and fault recovery operations. For example, faulty control valves can be blocked in and bypassed by a field operator. This situation requires careful coordination and communication between the console operator and the field operator to transfer control over to the bypass valve. This section provides the details of the scope of the field operator functions. The following types of field functions are supported in the Advanced Distillation simulator:

- Independent local gauges for verifying flow, level, pressure and temperature readings of all DCS instruments

- Suction and discharge block valves and pressure gauge for all pumps - Block and bypass valves for all major control valves - Valve position indications for all control valves and PSVs - On/Off hand switches for motors (these are common with the DCS) - Open/close hand switches for Tank Farm isolation valves (these are common

with the DCS) Note that block valves are controlled using DSS-100 switches (OPEN/CLOSED) while bypass valves are controlled using a DSS-100 PID (hand controller, 0–100%).




Virtual Field Operator, continued

Field Schematics

A set of DSS-100 schematics which present the field instruments and functions of the Advanced Distillation simulator are provided to allow easy setup of an exercise/initial condition by the instructor without having to navigate to the field functions with the VFO interface. For example, the instructor can open a bypass valve or block in a spare pump to set up a scenario where it will negatively affect the DCS operator’s ability to control the process. Another example is to set up an initial condition where all equipment is blocked in so that a pre-startup checklist can be followed by the field operator. Note: In initial condition no. 2 (COLD START), all field block valves are open and all control valve bypasses are closed. To create a condition where all field block valves are closed simply load initial condition no. 2, adjust all the block valves as desired and save the initial condition in an open slot on the DSS-100 initial condition menu. Refer to the DSS-100 User’s Guide for details of how to create and manage custom initial conditions on your training system. The following schematics show the scope of the field functions in the Advanced Distillation simulator:

- Schematic 9 – Feed Tank - Schematic 10 – Feed Pumps - Schematic 11 – Feed Preheater - Schematic 12 – Distillation Column - Schematic 13 – Column Bottoms - Schematic 14 – Condenser - Schematic 15 – Reflux Pumps - Schematic 16 – Light Product Tank - Schematic 17 – Heavy Product Tank - Schematic 18 – Off-Spec Tank - Schematic 19 – Flare KO Drum - Schematic 20 – Flare Stack





Schematic 9 Feed Tank

Schematic 10 Feed Pumps




Schematic 11 Feed Preheater

Schematic 12 Distillation Column




Schematic 13 Column Bottoms

Schematic 14 Condenser




Schematic 16 Light Product Tank

Schematic 17 Heavy Product Tank




Schematic 18 Off-Spec Tank

Schematic 19 Flare KO Drum




Schematic 20 Flare Stack



Appendix: Standard Score Details

Exercise Base Duration Steps Safety/min Alarms Deviation/min Quality 1 2 150 85 331,379.22 36 4,155,626.75 39,318.76 2 1 120 89 144,167.81 0 3,801,187.25 56,754.83 3 1 10 1 3,262.12 0 567,259.13 11,581.13 4 1 15 1 4,860.76 0 680,672.25 16,077.34 5 1 30 14 56,544.59 2 2,315,704.00 51,604.46

Exercise Base Duration Steps Safety/min Alarms Deviation/min Quality 1 2 150 85 69,655.19 36 2,593,659.00 33,845.37 2 1 120 89 30,537.88 0 2,877,065.75 53,002.27 3 1 10 1 699.70 0 330,475.19 7,892.24 4 1 15 1 779.17 0 453,412.94 13,059.98 5 1 30 14 8,989.75 2 1,791,477.38 40,039.17

metric units spm-721 advanced distillation€¦ · instrumentation 15 pre-startup 29 startup 30...

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