Principles and Case Studies of Simultaneous Design

PREFACE xv

1 INTRODUCTION 1

1.1 Overview / 1

1.2 History / 3

1.3 Books / 4

1.4 Tools / 4

Reference Textbooks / 5

2 PRINCIPLES OF REACTOR DESIGN AND CONTROL 7

2.1 Background / 7

2.2 Principles Derived from Chemistry / 8

2.2.1 Heat of Reaction / 8

2.2.2 Reversible and Irreversible Reactions / 9

2.2.3 Multiple Reactions / 10

2.3 Principles Derived from Phase of Reaction / 11

2.4 Determining Kinetic Parameters / 12

2.4.1 Thermodynamic Constraints / 12

2.4.2 Kinetic Parameters from Plant Data / 13

2.5 Principles of Reactor Heat Exchange / 13

2.5.1 Continuous Stirred-Tank Reactors / 13

2.5.2 Tubular Reactors / 14

2.5.3 Feed-Effluent Heat Exchangers / 16

2.6 Heuristic Design of Reactor/Separation Processes / 17

2.6.1 Introduction / 17

2.6.2 Process Studied / 18

2.6.3 Economic Optimization / 21

2.6.4 Other Cases / 22

2.6.5 Real Example / 27

2.7 Conclusion / 28

References / 29

3 PRINCIPLES OF DISTILLATION DESIGN AND CONTROL 31

3.1 Principles of Economic Distillation Design / 32

3.1.1 Operating Pressure / 32

3.1.2 Heuristic Optimization / 33

3.1.3 Rigorous Optimization / 33

3.1.4 Feed Preheating and Intermediate Reboilers and Condensers / 34

3.1.5 Heat Integration / 34

3.2 Principles of Distillation Control / 35

3.2.1 Single-End Control / 36

3.2.2 Dual-End Control / 38

3.2.3 Alternative Control Structures / 38

3.3 Conclusion / 39

References / 39

4 PRINCIPLES OF PLANTWIDE CONTROL 41

4.1 History / 42

4.2 Effects of Recycle / 42

4.2.1 Time Constants of Integrated Plant with Recycle / 42

4.2.2 Recycle Snowball Effect / 43

4.3 Management of Fresh Feed Streams / 45

4.3.1 Fundamentals / 45

4.3.2 Process with Two Recycles and Two Fresh Feeds / 46

4.4 Conclusion / 52

5 ECONOMIC BASIS 53

5.1 Level of Accuracy / 53

5.2 Sizing Equipment / 54

5.2.1 Vessels / 54

5.2.2 Heat Exchangers / 55

5.2.3 Compressors / 56

5.2.4 Pumps, Valves, and Piping / 56

5.3 Equipment Capital Cost / 56

5.3.1 Vessels / 56

5.3.2 Heat Exchangers / 56

5.3.3 Compressors / 57

5.4 Energy Costs / 57

5.5 Chemical Costs / 57

References / 57

6 DESIGN AND CONTROL OF THE ACETONE PROCESS VIA DEHYDROGENATION OF ISOPROPANOL 59

6.1 Process Description / 60

6.1.1 Reaction Kinetics / 61

6.1.2 Phase Equilibrium / 62

6.2 Turton Flowsheet / 62

6.2.1 Vaporizer / 63

6.2.2 Reactor / 64

6.2.3 Heat Exchangers, Flash Tank, and Absorber / 64

6.2.4 Acetone Column C1 / 66

6.2.5 Water Column C2 / 66

6.3 Revised Flowsheet / 66

6.3.1 Effect of Absorber Pressure / 66

6.3.2 Effect of Water Solvent and Absorber Stages / 68

6.3.3 Effect of Reactor Size / 68

6.3.4 Optimum Distillation Design / 69

6.4 Economic Comparison / 69

6.5 Plantwide Control / 71

6.5.1 Control Structure / 71

6.5.2 Column Control Structure Selection / 75

6.5.3 Dynamic Performance Results / 76

6.6 Conclusion / 81

References / 81

7 DESIGN AND CONTROL OF AN AUTO-REFRIGERATED ALKYLATION PROCESS 83

7.1 Introduction / 84

7.2 Process Description / 84

7.2.1 Reaction Kinetics / 85

7.2.2 Phase Equilibrium / 85

7.2.3 Flowsheet / 86

7.2.4 Design Optimization Variables / 88

7.3 Design of Distillation Columns / 89

7.3.1 Depropanizer / 89

7.3.2 Deisobutanizer / 89

7.4 Economic Optimization of Entire Process / 91

7.4.1 Flowsheet Convergence / 91

7.4.2 Yield / 91

7.4.3 Effect of Reactor Size / 91

7.4.4 Optimum Economic Design / 93

7.5 Alternative Flowsheet / 94

7.6 Plantwide Control / 96

7.6.1 Control Structure / 96

7.6.2 Controller Tuning / 100

7.6.3 Dynamic Performance / 101

7.7 Conclusion / 103

References / 105

8 DESIGN AND CONTROL OF THE BUTYL ACETATE PROCESS 107

8.1 Introduction / 108

8.2 Chemical Kinetics and Phase Equilibrium / 108

8.2.1 Chemical Kinetics and

Chemical Equilibrium / 108

8.2.2 Vapor-Liquid Equilibrium / 110

8.3 Process Flowsheet / 112

8.3.1 Reactor / 112

8.3.2 Column C1 / 113

8.3.3 Column C2 / 113

8.3.4 Column C3 / 113

8.3.5 Flowsheet Convergence / 115

8.4 Economic Optimum Design / 117

8.4.1 Reactor Size and Temperature / 117

8.4.2 Butanol Recycle and Composition / 118

8.4.3 Distillation Column Design / 119

8.4.4 System Economics / 120

8.5 Plantwide Control / 121

8.5.1 Column C1 / 121

8.5.2 Column C2 / 122

8.5.3 Column C3 / 122

8.5.4 Plantwide Control Structure / 123

8.5.5 Dynamic Performance / 124

8.6 Conclusion / 133

References / 133

9 DESIGN AND CONTROL OF THE CUMENE PROCESS 135

9.1 Introduction / 136

9.2 Process Studied / 136

9.2.1 Reaction Kinetics / 136

9.2.2 Phase Equilibrium / 137

9.2.3 Flowsheet / 137

9.3 Economic Optimization / 140

9.3.1 Increasing Propylene Conversion / 140

9.3.2 Effects of Design Optimization Variables / 141

9.3.3 Economic Basis / 142

9.3.4 Economic Optimization Results / 143

9.4 Plantwide Control / 147

9.5 Conclusion / 158

References / 158

10 DESIGN AND CONTROL OF THE ETHYL BENZENE PROCESS 159

10.1 Introduction / 159

10.2 Process Studied / 160

10.2.1 Reaction Kinetics / 161

10.2.2 Phase Equilibrium / 162

10.2.3 Flowsheet / 163

10.3 Design of Distillation Columns / 164

10.3.1 Column Pressure Selection / 166

10.3.2 Number of Column Trays / 169

10.4 Economic Optimization of Entire Process / 169

10.5 Plantwide Control / 172

10.5.1 Distillation Column Control Structure / 172

10.5.2 Plantwide Control Structure / 173

10.5.3 Controller Tuning / 174

10.5.4 Dynamic Performance / 174

10.5.5 Modified Control Structure / 176

10.6 Conclusion / 183

References / 183

11 DESIGN AND CONTROL OF A METHANOL REACTOR/COLUMN PROCESS 185

11.1 Introduction / 185

11.2 Process Studied / 186

11.2.1 Compression and Reactor Preheating / 186

11.2.2 Reactor / 187

11.2.3 Separator, Recycle, and Vent / 187

11.2.4 Flash and Distillation / 188

11.3 Reaction Kinetics / 188

11.4 Overall and Per-Pass Conversion / 189

11.5 Phase Equilibrium / 191

11.6 Effects of Design Optimization Variables / 192

11.6.1 Economic Basis / 192

11.6.2 Effect of Pressure / 193

11.6.3 Effect of Reactor Size / 195

11.6.4 Effect of Vent/Recycle Split / 196

11.6.5 Effect of Flash-Tank Pressure / 197

11.6.6 Optimum Distillation Column Design / 198

11.7 Plantwide Control / 201

11.7.1 Control Structure / 201

11.7.2 Column Control Structure Selection / 203

11.7.3 High-Pressure Override Controller / 203

11.7.4 Dynamic Performance Results / 204

11.8 Conclusion / 209

References / 210

12 DESIGN AND CONTROL OF THE METHOXY-METHYL-HEPTANE PROCESS 211

12.1 Introduction / 211

12.2 Process Studied / 212

12.2.1 Reactor / 212

12.2.2 Column C1 / 213

12.2.3 Column C2 / 213

12.2.4 Column C3 / 213

12.3 Reaction Kinetics / 213

12.4 Phase Equilibrium / 215

12.5 Design Optimization / 215

12.5.1 Economic Basis / 216

12.5.2 Reactor Size versus Recycle Trade-Off / 216

12.6 Optimum Distillation Column Design / 220

12.6.1 Column Pressures / 220

12.6.2 Number of Stages / 220

12.6.3 Column Profiles / 222

12.7 Plantwide Control / 223

12.7.1 Control Structure / 225

12.7.2 Dynamic Performance Results / 227

12.8 Conclusion / 230

References / 231

13 DESIGN AND CONTROL OF A METHYL ACETATE PROCESS USING CARBONYLATION OF DIMETHYL ETHER 233

13.1 Introduction / 233

13.2 Dehydration Section / 234

13.2.1 Process Description of Dehydration Section / 234

13.2.2 Dehydration Kinetics / 235

13.2.3 Alternative Flowsheets / 236

13.2.4 Optimization of Three Flowsheets / 240

13.3 Carbonylation Section / 245

13.3.1 Process Description / 246

13.3.2 Carbonylation Kinetics / 247

13.3.3 Effect of Parameters / 248

13.3.4 Flowsheet Convergence / 250

13.3.5 Optimization / 251

13.4 Plantwide Control / 255

13.4.1 Control Structure / 255

13.4.2 Dynamic Performance / 261

13.5 Conclusion / 262

References / 262

14 DESIGN AND CONTROL OF THE MONO-ISOPROPYL AMINE PROCESS 263

14.1 Introduction / 263

14.2 Process Studied / 264

14.2.1 Reaction Kinetics / 264

14.2.2 Phase Equilibrium / 265

14.2.3 Flowsheet / 266

14.3 Economic Optimization / 268

14.3.1 Design Optimization Variables / 268

14.3.2 Optimization Results / 269

14.4 Plantwide Control / 270

14.4.1 Dynamic Model Sizing / 271

14.4.2 Distillation Column Control Structures / 272

14.4.3 Plantwide Control Structure / 276

14.5 Conclusion / 289

References / 290

15 DESIGN AND CONTROL OF THE STYRENE PROCESS 291

15.1 Introduction / 292

15.2 Kinetics and Phase Equilibrium / 293

15.2.1 Reaction Kinetics / 293

15.2.2 Phase Equilibrium / 294

15.3 Vasudevan et al. Flowsheet / 295

15.3.1 Reactors / 295

15.3.2 Condenser and Decanter / 295

15.3.3 Product Column C1 / 296

15.3.4 Recycle Column C2 / 298

15.4 Effects of Design Optimization Variables / 298

15.4.1 Effect of Process Steam / 298

15.4.2 Effect of Reactor Inlet Temperature / 301

15.4.3 Effect of Reactor Size / 302

15.4.4 Optimum Distillation Column Design / 303

15.4.5 Number of Reactors / 304

15.4.6 Reoptimization / 304

15.4.7 Other Improvements / 305

15.5 Proposed Design / 305

15.6 Plantwide Control / 306

15.6.1 Control Structure / 306

15.6.2 Column Control Structure Selection / 310

15.6.3 Dynamic Performance Results / 312

15.7 Conclusion / 317

References / 317

NOMENCLATURE 319

INDEX 321