A Real-Time Approach to Process Control

362 Pages·2014·4.848 MB·English

by  William Y. Svrcek, Donald P. Mahoney, Brent R. Young

A Real-Time
Approach to
Process Control
Third Edition
William Y. Svrcek
Donald P. Mahoney
Brent R. Young

A Real-Time Approach
to Process Control

A Real-Time Approach
to Process Control
Third Edition
WILLIAM Y. SVRCEK
Department of Chemical and Petroleum Engineering,
University of Calgary, Canada
DONALD P. MAHONEY
Chemical Industry Business Solutions, SAP AG, USA
BRENT R. YOUNG
Department of Chemical and Materials Engineering,
University of Auckland, New Zealand
Thiseditionfirstpublished2014
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LibraryofCongressCataloging-in-PublicationData
Svrcek,WilliamY.
Areal-timeapproachtoprocesscontrol/WilliamY.Svrcek,DonaldP.Mahoney,BrentR.Young.–Thirdedition.
pagescm
Includesindex.
ISBN978-1-119-99387-2(cloth)–ISBN978-1-119-99388-9(pbk.)1.Processcontrol–Dataprocessing.
2.Real-timecontrol.I.Mahoney,DonaldP.II.Young,BrentR.III.Title.
TS156.8.S862014
670.42(cid:3)75433–dc23
2013030739
AcataloguerecordforthisbookisavailablefromtheBritishLibrary.
HBISBN:9781119993872
PBISBN:9781119993889
Setin10/12ptTimesbyAptaraInc.,NewDelhi,India.
1 2014
Contents
AuthorBiographies xi
ForewordandEndorsements xiii
Preface xv
Acknowledgements xvii
1 ABriefHistoryofProcessControlandProcessSimulation 1
1.1 ProcessControl 1
1.2 ProcessSimulation 5
References 11
2 ProcessControlHardwareFundamentals 15
2.1 ControlSystemComponents 15
2.2 PrimaryElements 16
2.2.1 PressureMeasurement 17
2.2.2 LevelMeasurement 21
2.2.3 TemperatureMeasurement 23
2.2.4 FlowMeasurement 26
2.2.5 QualityMeasurementandAnalyticalInstrumentation 32
2.2.6 ApplicationRangeandAccuracyofDifferentSensors 33
2.3 FinalControlElements 33
2.3.1 ControlValves 33
References 53
3 FundamentalsofSingle-Input/Single-OutputSystems 55
3.1 OpenLoopControl 55
3.2 Disturbances 56
3.3 FeedbackControl–Overview 57
3.4 FeedbackControl–ACloserLook 60
3.4.1 PositiveandNegativeFeedbacks 60
3.4.2 ControlElements 60
3.4.3 Sensor/Transmitter 63
3.4.4 Processes 63
3.4.5 FinalControlElement 65
3.4.6 Controller 65
vi Contents
3.5 ProcessAttributes–CapacitanceandDeadTime 66
3.5.1 Capacitance 67
3.5.2 DeadTime 71
3.6 ProcessDynamicResponse 74
3.7 ProcessModellingandSimulation 76
3.7.1 First-OrderSystems 76
3.7.2 Second-OrderandHigherOrderSystems 76
3.7.3 SimpleSystemAnalysis 83
3.7.4 ClassicalModellingforControlApproaches 89
3.7.5 TheModernModellingforControlApproach 92
References 93
4 BasicControlModes 95
4.1 On–OffControl 95
4.2 Proportional(P-Only)Control 97
4.3 Integral(I-Only)Control 102
4.4 ProportionalPlusIntegral(PI)Control 105
4.5 DerivativeAction 107
4.6 ProportionalPlusDerivative(PD)Controller 108
4.7 ProportionalIntegralDerivative(PID)Control 111
4.8 DigitalElectronicControllerForms 112
4.9 ChoosingtheCorrectController 112
4.10 ControllerHardware 114
References 117
5 TuningFeedbackControllers 119
5.1 QualityofControlandOptimization 119
5.1.1 ControllerResponse 120
5.1.2 ErrorPerformanceCriteria 122
5.2 TuningMethods 123
5.2.1 ‘TrialandError’Method 124
5.2.2 ProcessReactionCurveMethods 125
5.2.3 ConstantCyclingMethods 127
References 132
6 AdvancedTopicsinClassicalAutomaticControl 133
6.1 CascadeControl 133
6.1.1 StartingupaCascadeSystem 136
6.2 FeedforwardControl 137
6.3 RatioControl 140
6.4 OverrideControl(AutoSelectors) 142
6.4.1 ProtectionofEquipment 143
6.4.2 Auctioneering 145
6.4.3 RedundantInstrumentation 145
6.4.4 ArtificialMeasurements 147
6.5 SplitRangeControl 147
References 149
Contents vii
7 CommonControlLoops 151
7.1 FlowLoops 151
7.2 LiquidPressureLoops 153
7.3 LiquidLevelControl 155
7.3.1 Proportional-OnlyControlforIntegratingProcesses 163
7.3.2 PIControllerTuningforIntegratingProcess 164
7.4 GasPressureLoops 165
7.5 TemperatureControlLoops 166
7.5.1 TheEndothermicReactorTemperatureControlLoop 168
7.5.2 TheExothermicReactorTemperatureControlLoop 170
7.6 PumpControl 172
7.7 CompressorControl 172
7.7.1 ReciprocatingCompressorControl 173
7.7.2 CentrifugalCompressorControl 173
7.8 BoilerControl 179
7.8.1 CombustionControl 180
7.8.2 WaterDrumLevelControl 181
7.8.3 WaterDrumPressureControl 181
7.8.4 SteamTemperatureControl 181
References 182
8 DistillationColumnControl 185
8.1 BasicTerms 185
8.2 Steady-StateandDynamicDegreesofFreedom 186
8.3 ControlSystemObjectivesandDesignConsiderations 188
8.4 MethodologyforSelectionofaControllerStructure 190
8.5 Level,Pressure,TemperatureandCompositionControl 192
8.5.1 LevelControl 192
8.5.2 PressureControl 193
8.5.3 TemperatureControl 198
8.5.4 CompositionControl 198
8.6 OptimizingControl 199
8.6.1 Example:BenzeneColumnwithaRectifying
SectionSidestream 199
8.7 DistillationControlSchemeDesignUsingSteady-StateModels 204
8.7.1 ScreeningControlStrategiesviaSteady-StateSimulation 206
8.7.2 ACaseStudy–TheWorkshopStabilizer 207
8.7.3 RespecifyingSimulationSpecifications 207
8.7.4 MimickingtheBehaviourofAnalysersorLabAnalyses 209
8.7.5 DevelopinganEconomicProfitabilityFunction 209
8.7.6 EvaluatingtheCandidateStrategies 210
8.7.7 EvaluatingtheCandidateStrategiesunderDisturbances 211
8.7.8 EvaluatingSensorStrategies 211
8.7.9 ExampleSummary 212
8.8 DistillationControlSchemeDesignUsingDynamicModels 212
References 213
viii Contents
9 UsingSteady-StateMethodsinaMulti-loopControlScheme 215
9.1 VariablePairing 215
9.2 TheRelativeGainArray 216
9.2.1 CalculatingtheRGAwithExperiments 216
9.2.2 CalculatingtheRGAUsingtheSteady-StateGainMatrix 218
9.2.3 InterpretingtheRGA 219
9.3 NiederlinskiIndex 220
9.4 DecouplingControlLoops 220
9.4.1 SingularValueDecomposition 221
9.5 TuningtheControllersforMulti-loopSystems 222
9.6 PracticalExamples 222
9.6.1 Example1:ATwo-StreamMixer 222
9.6.2 Example2:AConventionalDistillationColumn 226
9.7 Summary 232
References 232
10 Plant-WideControl 233
10.1 Short-TermversusLong-TermControlFocus 233
10.2 CascadedUnits 235
10.3 RecycleStreams 236
10.4 GeneralConsiderationsforPlant-WideControl 241
References 242
11 AdvancedProcessControl 245
11.1 AdvancedProcessControl 245
11.2 ModelPredictiveControl 246
11.3 DynamicMatrixControl 249
11.4 GeneralConsiderationsforModelPredictiveControlImplementation 253
References 254
AppendixA P&IDSymbols 257
AppendixB GlossaryofTerms 261
AppendixC NewCapabilitieswithControlTechnologyHardware
andSoftware 267
Workshop1 LearningthroughDoing 279
Workshop2 FeedbackControlLoopConcepts 283
Workshop3 ProcessCapacityandDeadTime 289
Workshop4 FeedbackControl 295
Workshop5 ControllerTuningforCapacityandDeadTimeProcesses 303