refinery crude unit advanced control – what? why?...

Refinery Crude Unit Refinery Crude Unit Advanced Control Advanced Control ––What? Why? How?What? Why? How?

Lou Heavner

Advanced Applied TechnologiesGroup

ProcessSystems and SolutionDivision

©2005 Emerson Process ManagementSlide 2

TopicsTopicsTopicsWhy Do Crude / Vacuum Units Need Advanced Controls?

What Advanced Controls Do We Implement?

What’s New And Different With Emerson APC Tools?

Case Study


Crude DistillationCrude Distillation

T-2106

Naphtha Stabilizer

HN

MK

LG

HG

HHG

LN

T-2101

RefluxDrum

Pump-arounds

Naphtha

LGO

HGO

Crude Oilfrom Heaters H-2101A/B

LP Steam Injection

Atmospheric Residue

To Vacuum Column T-2201

T-2105

T-2104

T-2103

T-2102

T-2107

TI

TI

TI

TI

TI

TI

TI

TI

TI

TI

TI

TI

OverflashTI

TI

AID86 95%

AI

FI

Flash Pt. Density

AI

Cloud Pt. D86 5%

AICloud Pt.

AI

Color

PC

MV

MV

MV

MV

MV

*


Crude Unit Product VariabilityCrude Unit Product VariabilityCrude Unit Product Variability

654.000656.000658.000660.000662.000664.000666.000668.000670.000672.000674.000

7/5/00

7/5/00

7/6/00

7/6/00

7/7/00

7/7/00

7/8/00

7/8/00

7/9/00

7/9/00

7/10/00

Date

Die

sel 9

0%


Crude Unit CharacteristicsCrude Unit CharacteristicsCrude Unit CharacteristicsConditions Are Often Changing– Changing Crude Feed Compositions

– Changing Targets For Sidestream Qualities• Product Qualities Measured by Laboratory Samples or Online

Analyzers with a lot of delay

One Of The Largest Consumers Of Energy In The Refinery

One of the most INTERACTIVE units in the refinery –difficult to control

Primary Yields Set Overall Refinery Yields


Typical BenefitsTypical BenefitsTypical BenefitsUnit PredictPro Benefit

USc/ bbl Feed

Atmospheric Crude Units 5

Vacuum Distillation Units 5

FCCU Main Fractionator 4

Coker Main Fractionator 8


APC Improves QualityAPC Improves QualityAPC Improves QualityRemoves process variabilityProvides real-time predictions of unmeasured qualitiesCompensates for dead-time and analyzer delays

Hot-end Temperature PV

0

50

100

150

200

250

300

350

400

450

500

565

630

695

760

825

890

955

1020

1085

1150

Deg C

Freq

uenc

y

Before

Hot-end Temperature PV

0

50

100

150

200

250

300

350

400

450

500

555

610

665

720

775

830

885

940

995

1050

1105

1160

Deg C

Freq

uenc

y

AfterNaphtha 95%Point

Typically 40-80% reduction in

quality variation.


APC Increases ThroughputAPC Increases ThroughputAPC Increases ThroughputIdeal for managing multiple constraintsPredicts limit violations before they occurPush equipment and plant limits every minute of every day

Past Future

Constraints

Time

Throughput Production Increase $$

Throughput at limit

Operator Setpoint

APCTypically 3-10% increase in throughput.


APC Reduce Operations & Maintenance CostsAPC Reduce Operations & Maintenance APC Reduce Operations & Maintenance CostsCosts

Automation of routine tasks increases the loop count per operator

“Safe Park” applications lowers risks during process upsets

More stable operation reduces wear-and-tear on machinery

Typically 0-4% reduction in O&M

costs.


APC Reduce IncidentsAPC Reduce IncidentsAPC Reduce IncidentsPrediction and control against actual equipment limitsAutomated action on instrument or equipment failureMore stable operation reduces opportunity for excursionsTypically 10-20%

reduction in safety or environmental

incident risk.


APC Minimize Energy CostsAPC Minimize Energy CostsAPC Minimize Energy CostsDesigned to minimize energy when possibleMaximize equipment efficiency and heat recoveryOptimize tradeoffs in the site utility and fuel balance

Typically 2-6% reduction in energy

costs.


APC Reduces Off-spec and ReworkAPC Reduces OffAPC Reduces Off--spec and Reworkspec and ReworkReal-time prediction and control of key product qualitiesStable operation yields consistent, predictable qualitiesOn-spec blends every time leads to lower inventories and component costsTypically 5-10%

reduction in product inventories.


Hierarchy of Performance Control

Loop Performance

Process ControlDCS

EnterpriseControl

AdvancedControl

Improving Control Improving Control PerformancePerformance


Reducing Input Disturbances – Fuel Gas Reducing Input Disturbances Reducing Input Disturbances –– Fuel Gas Fuel Gas

28.7757.79Hydrogen

10.99635.38Butane

11.08488.53Propane

11.35341.26Ethane

11.95191.76Methane

Kcal/gmKcal/moleHeat Combustion

Conclusion: Measure and control by mass – not by volume!


Reducing Variability – Remove Disturbances -Heater ControlsReducing Variability Reducing Variability –– Remove Disturbances Remove Disturbances --Heater ControlsHeater Controls

Fuel Gas with Mass Control and Density Feedforward

O2

PI


Heater Excess Air ControlHeater Excess Air ControlHeater Excess Air Control


Main Crude UnitMain Crude UnitMain Crude UnitMain feed valve deadband was 5-7%. This caused pressure fluctuations to the desalter units in the preheat train. A lower pressure setpoint was necessary to avoid lifting relief valves.

The main feed valve was replaced with a 12” V300 control valve assembly and tuned using Lambda Tuning methodology (avoid interaction with the desalter pressure controller).

Pressure fluctuations were reduced to a +/- 1 psi allowing a higher pressure setpoint.

Throughput increases have averaged 2000 BPD with a desalterpressure controller setpoint increase.

This optimization is presently valued at $1,900,000 annually.

DeltaVDeltaV Advanced Advanced Control Control -- PredictProPredictPro


Yesterday’s Technology…YesterdayYesterday’’s Technologys Technology……

…required you to have a really big one!


DeltaV: Removing Obstacles To APC Implementation & MaintenanceDeltaV: Removing Obstacles To APC DeltaV: Removing Obstacles To APC Implementation & MaintenanceImplementation & Maintenance

Team of consultants

DeltaV APC Projects are 25-50% Faster and Less Costly than

traditional APC Projects


Embedded APC Tools – What’s new?Embedded APC Tools Embedded APC Tools –– WhatWhat’’s new?s new?• NO extra

databases• NO database

synchronization issues

• NO watchdog timers

• NO fail/shed logic design

• NO custom DCS programming

• NO interface programming

• NO operator interface development

Traditional Advanced Control

Embedded APC:

• Can run in DCS controllers

• Redundant and fast (1/sec)

• Integrated operator user interface

• Configured in DeltaV environment

• Automated step testing and Model ID


Typical APC Project TimelineTypical APC Project TimelineTypical APC Project Timeline

1 2 3 4 5 6Months

107 9 118 12

Functional Design

Det. Design, Config & Staging

Step Tests & Model IDTraditional APC Technology Commissioning

Functional Design

Det. Design & Config

Step Tests & Model IDCommissioning

Performed on-site

Embedded APC Technology


DeltaV PredictPRODeltaV PredictPRODeltaV PredictPRO


Classical Feedback ControlClassical Feedback ControlClassical Feedback Control

PID Algorithmto makeError zero

Plant

Current measured value for singlecontrolled variableSetpoint

Error

Movesingle manipulatedvariable

+ -

Control Moves Based on Current Measurement


Multivariable Predictive Constraint ControlMultivariable Predictive Constraint ControlMultivariable Predictive Constraint Control

Uses Information fromThe Past

To Predict The Future

Controlled Variable

Past Present Future

Time

Manipulated Variable

ModeledRelationship


Multi-Variable Control ProblemMultiMulti--Variable Control ProblemVariable Control Problem

Controller

DistillationProcess

-

+ RefluxTemperature

Controller

-

+

Temperature

Reboil


Multi-Variable Control ProblemMultiMulti--Variable Control ProblemVariable Control Problem

Controller

-

+

Controller

-

+Temperature

Temperature

Reflux

Reboil


Plant

Multivariable PredictiveConstraintController

MultipleSetpoints

Multiple measurementsof controlled

variables

Multiple manipulated variable moves

based on predicted plant behaviour

Multivariable Predictive Constraint ControlMultivariable Predictive Constraint ControlMultivariable Predictive Constraint Control

MultipleConstraints

MeasuredDisturbances

Benefits: Reduction in Standard Deviation of 30 to 70%


Historically, Advanced Control Was Done in Supervisory ComputersHistorically, Advanced Control Historically, Advanced Control Was Done in Supervisory ComputersWas Done in Supervisory Computers

LAN

Advanced Process Control• Not redundant• Not real-time

(1 minute)

Proprietary Bus

DCS Controller

APC

PID


DeltaV Predict in the ControllerDeltaV Predict in the ControllerDeltaV Predict in the Controller

LAN

Advanced Process Control• Not redundant• Real-time(1 minute)

Proprietary Bus

LAN

Open Bus

• Redundant and Fault Tolerant

• Real-time(1 second)

• Communicates data throughout enterprise

Fieldbus

PID

DCS ControllerAPC

PID

APC


MPC Implementation SequenceMPC Implementation SequenceMPC Implementation Sequence1. PreTest and Variable Selection

2. Configure

3. Process Testing

4. Model Building and Validation

5. Controller Simulation

6. Build Operator Interface

7. Controller Download

8. Controller Operation


Step 2 - Graphical Configuration - MPCProFunction BlockStep 2 Step 2 -- Graphical Configuration Graphical Configuration -- MPCProMPCProFunction BlockFunction Block


Configure the MPCPro by Selecting Properties Configure the MPCPro by Selecting Configure the MPCPro by Selecting Properties Properties


Attributes for Control, Manipulated, Disturbance and Constraint ParametersAttributes for Control, Manipulated, Attributes for Control, Manipulated, Disturbance and Constraint ParametersDisturbance and Constraint Parameters


Step 3 - Automated Step TestingStep 3 Step 3 -- Automated Step TestingAutomated Step Testing

Process Steps

Step SizeTss

Manipulated inputs selected for test are changed in a pseudo-random fashion during the test based on the step size and initial starting manipulated input value.


Step 4 – Model Validation - Process Model Displays ProducedStep 4 Step 4 –– Model Validation Model Validation -- Process Model Process Model Displays ProducedDisplays Produced


Model ValidationModel ValidationModel Validation


Step 5 - Controller SimulationStep 5 Step 5 -- Controller SimulationController Simulation


Step 6 : Automatic Operator DisplayStep 6 : Automatic Operator DisplayStep 6 : Automatic Operator Display

Trend Window

Past Future

CVs MVs DVsLVs


BuiltBuilt--in LP Optimizationin LP Optimization

100% position

0% position

0% p

ositi

on

100%

pos

ition

80 deg F

120 deg F

50 psi

100 psi

Maximized ThroughputMaximized

ProfitMinimized

Energy


DeltaV NeuralDeltaV NeuralDeltaV Neural

– Create real-time “virtual sensors” for periodic lab measurements

– Easy to understand and use

– Easy to update and maintain


Property EstimationProperty EstimationProperty EstimationWhen critical measurements are slow to reflect process changes or only lab analysis is available, then parameter estimation can often be used to improve the performance of control and monitoring applications.

Measured process inputs their relationship to the property of some process output is used to infer an estimate of the output.


Example: Crude Column Product QualityExample: Crude Column Product Example: Crude Column Product QualityQuality

Predict product qualities from temperature / pressure profile

– Distillation properties (IBP, 90, EP)

– Pour, cloud, SUS

Updated from lab measurements

Real-time estimate used for control

Crude Column

VirtualSensorVirtualSensor

FC

FC

FC

FC

FC

FC

FI

FI

TI

TC

FC

TI

TI

TI

TI

TI

TI

FC

PC

EP


EP


PP


PP

TI


Distillation Control ModuleDistillation Control ModuleDistillation Control Module

Standard Distillation Calcs

Predict Pro Block

Preconfigured Neural Blocks

Module Library


SmartProcess ImplementationSmartProcess ImplementationSmartProcess Implementation

1 2 3 4 5 6Months

107 9 118 12

Traditional APC TechnologyFunctional Design

Det. Design, Config & Staging

Step Tests & Model IDCommissioningFunctional Design

Det. Design & Config

Step Tests & Model IDCommissioning Embedded APC Technology

CommissioningStep Tests & Model ID

FDS & Confg

SmartProcess Applications

Implementing Advanced Implementing Advanced ControlControl


Refinery APC ExampleRefinery APC ExampleRefinery APC Example

Ergon, West VirginiaErgon, West VirginiaErgon, West Virginia


Ergon Project ScopeErgon Project ScopeErgon Project ScopeAtmospheric Crude and Vacuum Units

2 Model Predictive Controllers – 4 x 4, 3 x 3

3 Neural Networks– SR Naphtha 95% point

– AGO 95% point

– Wax distillate 95% point


Atmospheric Column 4 Controlled VariablesAtmospheric Column Atmospheric Column 4 Controlled Variables4 Controlled Variables

Naphtha

Kero

Hvy Kero

AGO

Resid to VAC Column

FC

FC

FC

FC

TC

Crude

Fuel Gas

TC

MPC

TI

TI

TI PCT

PCT

PCT

PCT


Atmospheric Column 4 Manipulated VariablesAtmospheric Column Atmospheric Column 4 Manipulated Variables4 Manipulated Variables

Naphtha

Kero

Hvy Kero

AGO

Resid to VAC Column

FC

FC

FCFC

FC

FC

FC

FC

TC

Crude

Fuel Gas

TC

MPC


Atmospheric Column 3 Disturbance VariablesAtmospheric Column Atmospheric Column 3 Disturbance Variables3 Disturbance Variables

Naphtha

Kero

Hvy Kero

AGO

Resid to VAC Column

FC

FC

FC

FC

TC

Crude

Fuel Gas

TC

MPC

TI

TI

TI

TI


Atmospheric ColumnNeural Network PredictionsAtmospheric ColumnAtmospheric ColumnNeural Network PredictionsNeural Network Predictions

Naphtha

Kero

Hvy Kero

AGOFC

FC

FCFC

FC

FC

FC

FC

TC

Crude

Fuel Gas

TCPredicted NA

End Point

Predicted AGO End Point

Column Temps & Yields

Column Temps& Yields

Resid to VAC Column


TC

Vacuum ColumnControlled VariablesVacuum ColumnVacuum ColumnControlled VariablesControlled Variables

VGO

Wax Dist

Hvy Wax Dist

VAC Resid

FC

FC

LC

FC

FC

Atm Btms

Fuel Gas

TC

FC

VAC P/A

PC

TI

TI

MPC

PCT

PCT

PCT


TC

Vacuum ColumnManipulated VariablesVacuum ColumnVacuum ColumnManipulated VariablesManipulated Variables

VGO

Wax Dist

Hvy Wax Dist

VAC Resid

FC

FC

LC

FC

FC

FC

FC

Atm Btms

Fuel Gas

TC

FC

VAC P/A

PC

MPC


TC

Vacuum ColumnDisturbance VariablesVacuum ColumnVacuum ColumnDisturbance VariablesDisturbance Variables

VGO

Wax Dist

Hvy Wax Dist

VAC Resid

FC

FC

LC

FC

FC

FC

FC

Atm Btms

Fuel Gas

FC

VAC P/A

PC

TI

MPC


Vacuum ColumnNeural Network PredictionVacuum ColumnVacuum ColumnNeural Network PredictionNeural Network Prediction

TC

VGO

Wax Dist

Hvy Wax DistFC

FC

LC

FC

FC

FC

FC

Atm Btms

Fuel Gas

TC

FC

VAC P/A

PC

TI

TI

Predicted Wax Distillate

95% Point

Column Temps& Yields

VAC Resid


Atm Controller PerformanceAtmAtm Controller PerformanceController PerformanceController

ON

Naphtha

Kero AGO

Hvy Kero

Crude Change

CVSPMVLabSpec


Neural Results – Naphtha 95% PointNeural Results Neural Results –– Naphtha 95% PointNaphtha 95% Point

SR Naphtha EP

340345350355360365370375380

07-Aug-0300:00:00

09-Aug-0300:00:00

11-Aug-0300:00:00

13-Aug-0300:00:00

LabNN PredictionFiltered

Crude Switch


Variability ReductionVariability ReductionVariability ReductionBefore After

Average St. Dev. Average St. Dev.Reduction in Std.

Dev.Atm Column

SR NAPHTHA EP 349.55 14.89 347.10 4.30 71.1%AGO EP 636.32 10.54 634.41 6.22 41.0%

OVERHEAD TEMP 253.18 5.01 260.91 1.80 64.1%KERO DRAW TEMP 362.59 4.60 366.60 1.86 59.5%HVY KERO TEMP 459.37 5.65 462.72 2.60 54.0%

AGO DRAW TEMP 528.14 5.60 530.77 2.55 54.5%

Vacuum ColumnWAX DIST 95% POINT 934.36 12.28 933.78 8.56 30.3%

VGO CHIMNEY TEMP 358.58 7.32 365.74 3.23 55.8%WAX VAP TEMP 542.47 5.99 599.50 2.29 61.8%H WAX VAP TEMP 651.77 5.39 671.75 3.74 30.7%


Crude/Vac Unit APC Project TimelineCrude/Crude/VacVac Unit APC Project TimelineUnit APC Project Timeline

Activity Timeframe

Functional Design Specification 3 weeks

Application Configuration < 1 day

Step Tests 10 days

Commissioning 1 week

DeltaV APC Projects are 25-50% Faster and Less Costly than traditional

APC Projects

Scope: Two 4x4 MPC controllers, 3 Neural Nets


Standard Operator DisplayStandard Operator DisplayStandard Operator Display


SummarySummarySummaryAPC has a large value for Crude Units

DeltaV Embedded APC dramatically lowers implementation costs– Less need for expensive consultants

– Quicker implementation

– Easier to maintain

Can be used with other DCS platforms

Simple Optimization can be done in APC layer


Learning More About DeltaV Advanced ControlLearning More About DeltaV Advanced ControlLearning More About DeltaV Advanced ControlBook was inspired by DeltaV Advanced Control Products. This book was introduced at ISA2002 may also be ordered through ISA, Amazon.com or at EasyDeltaV.com/Bookstore

The application sections include guided tours based on DeltaV Advanced Control Products

CD provides an overview video for each section and examples. Copies of the displays, modules, andHYSYS Cases are included on the CD.


Questions? Comments?Questions? Comments?Questions? Comments?

Questions? – contact

[email protected]

(512) 834-7262

mailto:[email protected]


Thank You!

Questions?

refinery crude unit advanced control – what? why?...

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