Completely revised and updated to reflect the current IUPAC standards, this second edition is enlarged by five new chapters dealing with the assessment of energy potential, physical unit operations, emergency pressure relief, the reliability of risk reducing measures, and process safety and process development.
Clearly structured in four parts, the first provides a general introduction and presents the theoretical, methodological and experimental aspects of thermal risk assessment. Part II is devoted to desired reactions and techniques allowing reactions to be mastered on an industrial scale, while the third part deals with secondary reactions, their characterization, and techniques to avoid triggering them. Due to the inclusion of new content and restructuring measures, the technical aspects of risk reduction are highlighted in the new section that constitutes the final part.
Each chapter begins with a case history illustrating the topic in question, presenting lessons learned from the incident. Numerous examples taken from industrial practice are analyzed, and each chapter concludes with a series of exercises or case studies, allowing readers to check their understanding of the subject matter. Finally, additional control questions have been added and solutions to the exercises and problems can now be found.
Table of Contents
Preface xxi
Acknowledgments xxv
Part I General Aspects of Thermal Process Safety 1
1 Introduction to Risk Analysis of Fine Chemical Processes 3
1.1 Chemical Industry and Safety 4
1.1.1 Chemical Industry and Society 4
1.1.2 Responsibility 6
1.1.3 Definitions and Concepts 7
1.2 Steps of Risk Analysis 8
1.2.1 Scope of Analysis 9
1.2.2 Safety Data Collection 10
1.2.3 Safe Conditions and Critical Limits 10
1.2.4 Identification of Deviations 10
1.2.5 Risk Assessment 11
1.2.6 Risk Matrixes 14
1.2.7 Risk-Reducing Measures 15
1.2.8 Residual Risk 17
1.3 Safety Data 17
1.3.1 Physical Properties 18
1.3.2 Chemical Properties 18
1.3.3 Toxicity 18
1.3.4 Ecotoxicity 20
1.3.5 Fire and Explosion Data 20
1.3.6 Interactions 21
1.4 Systematic Identification of Hazards 21
1.4.1 Checklist Method 22
1.4.2 Failure Mode and Effect Analysis 24
1.4.3 Hazard and Operability Study 24
1.4.4 Decision Table 26
1.4.5 Event Tree Analysis 26
1.4.6 Fault Tree Analysis 27
1.4.7 Brainstorming 29
1.5 The Practice of Risk Analysis 29
1.5.1 Preparing the Risk Analysis 29
1.5.2 The Risk Analysis Team 30
1.5.3 The Team Leader 30
1.5.4 Finalizing the Risk Analysis 31
1.6 Exercises 31
References 32
2 Fundamentals of Thermal Process Safety 35
2.1 Energy Potential 37
2.1.1 Thermal Energy 37
2.1.2 Pressure Effects 41
2.2 Effect of Temperature on Reaction Rate 41
2.2.1 Single Reaction 41
2.2.2 Multiple Reactions 42
2.3 Heat Balance 43
2.3.1 Terms of the Heat Balance 43
2.3.2 Simplified Expression of the Heat Balance 48
2.3.3 Reaction Rate Under Adiabatic Conditions 49
2.4 Runaway Reactions 50
2.4.1 Thermal Explosions 50
2.4.2 Semenov Diagram 51
2.4.3 Parametric Sensitivity 52
2.4.4 Critical Temperature 53
2.4.5 Sensitivity Toward Variation of the Coolant Temperature 55
2.4.6 Time Frame of a Thermal Explosion, the tmrad Concept 56
2.5 Exercises 57
References 59
3 Assessment of Thermal Risks 61
3.1 Thermal Process Safety 62
3.1.1 Thermal Risks 62
3.1.2 Processes Concerned by Thermal Risks 62
3.2 Thermal Risk Assessment Criteria 63
3.2.1 Cooling Failure Scenario 63
3.2.2 Severity 66
3.2.3 Probability 68
3.2.4 Runaway Risk Assessment 70
3.3 Criticality of Chemical Processes 70
3.3.1 Assessment of the Criticality 70
3.3.2 Criticality Classes 72
3.3.3 Special Cases of Criticality Assessment 76
3.3.4 Remarks on Criticality Class 5 76
3.3.5 Using MTT as a Safety Barrier 77
3.4 Assessment Procedures 81
3.4.1 General Rules for Thermal Safety Assessment 81
3.4.2 Practical Procedure for the Assessment of Thermal Risks 81
3.5 Exercises 85
References 87
4 Experimental Techniques 89
4.1 Calorimetric Measurement Principles 90
4.1.1 Classification of Calorimeters 90
4.1.2 Temperature Control Modes of Calorimeters 90
4.1.3 Heat Balance in Calorimeters 92
4.2 Instruments Used in Safety Laboratories 94
4.2.1 Characteristics of Instruments Used for Safety Studies 94
4.2.2 Example of Instruments Used for Safety Studies 97
4.3 Microcalorimeters 97
4.3.1 Differential Scanning Calorimetry (DSC) 97
4.3.2 Calvet Calorimeters 104
4.3.3 Thermal Activity Monitor 106
4.4 Reaction Calorimeters 107
4.4.1 Purpose of Reaction Calorimeters 107
4.4.2 Principles of Reaction Calorimeters 108
4.4.3 Examples of Reaction Calorimeters 110
4.4.4 Applications 113
4.5 Adiabatic Calorimeters 114
4.5.1 Principle of Adiabatic Calorimetry 114
4.5.2 On the Thermal Inertia 115
4.5.3 Dewar Calorimeters 116
4.5.4 Accelerating Rate Calorimeter (ARC) 119
4.5.5 Vent Sizing Package (VSP) 121
4.6 Exercises 122
References 126
5 Assessment of the Energy Potential 131
5.1 Thermal Energy 132
5.1.1 Thermal Energy of Synthesis Reactions 132
5.1.2 Energy Potential of Secondary Reactions 133
5.1.3 Adiabatic Temperature Rise 136
5.2 Pressure Effects 137
5.2.1 Gas Release 137
5.2.2 Vapor Pressure 138
5.2.3 Amount of Solvent Evaporated 139
5.3 Experimental Determination of Energy Potentials 140
5.3.1 Experimental Techniques 140
5.3.2 Choosing the Sample to be Analyzed 141
5.3.3 Assessment of Process Deviations 144
5.4 Exercises 147
References 149
Part II Mastering Exothermal Reactions 153
6 General Aspects of Reactor Safety 155
6.1 Dynamic Stability of Reactors 157
6.1.1 Parametric Sensitivity 157
6.1.2 Sensitivity Toward Temperature: Reaction Number B 157
6.1.3 Heat Balance 158
6.2 Reactor Safety After a Cooling Failure 163
6.2.1 Potential of the Reaction, the Adiabatic Temperature Rise 163
6.2.2 Temperature in Case of Cooling Failure: The Concept of MTSR 164
6.3 Example Reaction System 165
References 168
7 Batch Reactors 171
7.1 Chemical Reaction Engineering Aspects of Batch Reactors 172
7.1.1 Principles of Batch Reaction 172
7.1.2 Mass Balance 173
7.1.3 Heat Balance 174
7.1.4 Strategies of Temperature Control 174
7.2 Isothermal Reactions 175
7.2.1 Principles 175
7.2.2 Design of Safe Isothermal Reactors 175
7.2.3 Safety Assessment 178
7.3 Adiabatic Reaction 178
7.3.1 Principles 178
7.3.2 Design of a Safe Adiabatic Batch Reactor 178
7.3.3 Safety Assessment 179
7.4 Polytropic Reaction 179
7.4.1 Principles 179
7.4.2 Design of Polytropic Operation: Temperature Control 180
7.4.3 Safety Assessment 184
7.5 Isoperibolic Reaction 184
7.5.1 Principles 184
7.5.2 Design of Isoperibolic Operation: Temperature Control 184
7.5.3 Safety Assessment 184
7.6 Temperature-Controlled Reaction 185
7.6.1 Principles 185
7.6.2 Design of Temperature-Controlled Reaction 186
7.6.3 Safety Assessment 187
7.7 Key Factors for the Safe Design of Batch Reactors 188
7.7.1 Determination of Safety Relevant Data 188
7.7.2 Rules for Safe Operation of Batch Reactors 190
7.8 Exercises 193
References 195
8 Semi-batch Reactors 197
8.1 Principles of Semi-batch Reaction 198
8.1.1 Definition of Semi-batch Operation 198
8.1.2 Material Balance 199
8.1.3 Heat Balance of Semi-batch Reactors 200
8.2 Reactant Accumulation in Semi-batch Reactors 202
8.2.1 Fast Reactions 203
8.2.2 Slow Reactions 205
8.2.3 Design of Safe Semi-batch Reactors 207
8.3 Isothermal Reaction 208
8.3.1 Principles of Isothermal Semi-batch Operation 208
8.3.2 Design of Isothermal Semi-batch Reactors 208
8.3.3 Accumulation with Complex Reactions 212
8.4 Isoperibolic, Constant Cooling Medium Temperature 212
8.5 Non-isothermal Reaction 214
8.6 Strategies of Feed Control 215
8.6.1 Addition by Portions 215
8.6.2 Constant Feed Rate 215
8.6.3 Interlock of Feed with Temperature 217
8.6.4 Why Reducing the Accumulation 219
8.7 Choice of Temperature and Feed Rate 219
8.7.1 General Principle 219
8.7.2 Scale-Up from Laboratory to Industrial Scale 220
8.7.3 Online Detection of Unwanted Accumulation 221
8.8 Advanced Feed Control 222
8.8.1 Feed Control by the Accumulation 222
8.8.2 Feed Control by the Thermal Stability 224
8.9 Exercises 226
References 228
9 Continuous Reactors 231
9.1 Continuous Stirred Tank Reactors 232
9.1.1 Mass Balance 233
9.1.2 Heat Balance 233
9.1.3 Cooled CSTR 234
9.1.4 Adiabatic CSTR 234
9.1.5 The Autothermal CSTR 236
9.1.6 Safety Aspects 237
9.2 Tubular Reactors 240
9.2.1 Mass Balance 240
9.2.2 Heat Balance 241
9.2.3 Safety Aspects 242
9.2.4 Performance and Safety Characteristics of Ideal Reactors 246
9.3 Other Continuous Reactor Types 247
9.3.1 Cascade of CSTRs 248
9.3.2 Recycling Reactor 248
9.3.3 Microreactors 249
9.3.4 Process Intensification 251
9.4 Exercises 252
References 253
Part III Avoiding Secondary Reactions 255
10 Thermal Stability 257
10.1 Thermal Stability and Secondary Decomposition Reactions 258
10.2 Triggering Conditions 260
10.2.1 Onset: A Concept Without Scientific Base 260
10.2.2 Decomposition Kinetics, the tmrad Concept 261
10.2.3 Safe Temperature 262
10.2.4 Assessment Procedure 262
10.3 Estimation of Thermal Stability 264
10.3.1 Estimation of TD24 from One Dynamic DSC Experiment 264
10.3.2 Conservative Extrapolation 264
10.3.3 Empirical Rules for the Determination of a “Safe” Temperature 267
10.3.4 Prediction of Thermal Stability 268
10.4 Quantitative Determination of the TD24 269
10.4.1 Principle of Quantitative Determination Methods for the Heat Release Rate 269
10.4.2 Determination of q′ = f (T) from Isothermal Experiments 269
10.4.3 Determination of q′ = f (T) from Dynamic Experiments 273
10.4.4 Determination of TD24 275
10.5 Practice of Thermal Stability Assessment 276
10.5.1 Complex Reactions 276
10.5.2 Remarks on the Quality of Experiments and Evaluation 278
10.6 Exercises 278
References 281
11 Autocatalytic Reactions 283
11.1 Autocatalytic Decompositions 284
11.1.1 Definitions 284
11.1.2 Behavior of Autocatalytic Reactions 285
11.1.3 Rate Equations of Autocatalytic Reactions 286
11.1.4 Phenomenological Aspects of Autocatalytic Reactions 289
11.2 Identification of Autocatalytic Reactions 291
11.2.1 Chemical Information 291
11.2.2 Qualitative Peak Shape in a Dynamic DSC Thermogram 292
11.2.3 Quantitative Peak Shape Characterization 293
11.2.4 Double Scan Test 294
11.2.5 Identification by Isothermal DSC 296
11.3 Determination of tmrad of Autocatalytic Reactions 296
11.3.1 One-Point Estimation 296
11.3.2 Characterization Using Zero-Order Kinetics 297
11.3.3 Characterization Using a Mechanistic Approach 299
11.3.4 Characterization by Isoconversional Methods 301
11.3.5 Characterization by Adiabatic Calorimetry 302
11.4 Practical Safety Aspects for Autocatalytic Reactions 306
11.4.1 Specific Safety Aspects of Autocatalytic Reactions 306
11.4.2 Autocatalytic Decompositions in the Industrial Practice 307
11.4.3 Volatile Products as Catalysts 307
11.5 Exercises 308
References 309
12 Heat Accumulation 311
12.1 Heat Accumulation Situations 312
12.2 Heat Balance 313
12.2.1 Heat Balance Using Time Scale 314
12.2.2 Forced Convection, the Semenov Model 314
12.2.3 Natural Convection 315
12.2.4 High Viscosity Liquids, Pastes, and Solids 316
12.3 Heat Balance with Reactive Material 318
12.3.1 Conduction in a Reactive Solid with a Heat Source, the Frank-Kamenetskii Model 318
12.3.2 Conduction in a Reactive Solid with Temperature Gradient at the Wall, the Thomas Model 323
12.3.3 Conduction in a Reactive Solid with Formal Kinetics, the Finite Elements Model 324
12.4 Assessing Heat Accumulation Conditions 325
12.4.1 Thermal Explosion Models 325
12.4.2 Assessment Procedure 326
12.5 Exercises 332
References 333
13 Physical Unit Operations 335
13.1 Thermal Hazards in Physical Unit Operations 336
13.1.1 Introduction to Physical Unit Operations 336
13.1.2 Hazards in Physical Unit Operations 337
13.1.3 Assessment Procedure for Unwanted Exothermal Reactions 337
13.1.4 Specificities of Physical Unit Operations 338
13.1.5 Standardization of the Risk Assessment 338
13.2 Specific Testing Procedures 338
13.2.1 Shock Sensitivity: The Falling Hammer Test 339
13.2.2 Friction Sensitivity 339
13.2.3 DSC Dynamic 339
13.2.4 Decomposition Gases 340
13.2.5 Dynamic Decomposition Test (RADEX) 340
13.2.6 Mini Autoclave 341
13.2.7 Spontaneous Decomposition 341
13.2.8 Grewer Oven and Decomposition in Airstream 342
13.2.9 RADEX Isoperibolic Test 342
13.2.10 Self-Ignition Test in a 400 ml Basket 342
13.2.11 Warm Storage Test in a Dewar 343
13.3 Hazards Associated to Solid Processing 343
13.3.1 Pneumatic and Mechanical Conveying Operations 343
13.3.2 Blending 343
13.3.3 Storage 344
13.3.4 Drying 344
13.3.5 Milling and Grinding 345
13.3.6 Hot Discharge 346
13.4 Hazards During Liquid Processing 346
13.4.1 Transport Operations 346
13.4.2 Operations with Heat Exchange 347
13.4.3 Evaporation and Distillation 348
13.4.4 Failure Modes of Heat Exchangers and Evaporators 350
13.4.5 Risk Reducing Measures 352
13.5 Transport of Dangerous Goods and SADT 353
13.6 Exercises 354
References 356
Part IV Technical Aspects of Thermal Process Safety 357
14 Heating and Cooling Industrial Reactors 359
14.1 Temperature Control of Industrial Reactors 361
14.1.1 Technical Heat Carriers 361
14.1.2 Heating and Cooling Techniques 364
14.1.3 Temperature Control Strategies 368
14.1.4 Dynamic Aspects of Heat Exchange Systems 371
14.2 Heat Exchange Across theWall 375
14.2.1 Two Film Theory 375
14.2.2 The Internal Film Coefficient of a Stirred Tank 376
14.2.3 Determination of the Internal Film Coefficient 376
14.2.4 The Resistance of the Equipment to Heat Transfer 378
14.2.5 Practical Determination of Heat Transfer Coefficients 379
14.3 Evaporative Cooling 382
14.3.1 Amount of Solvent Evaporated 383
14.3.2 Vapor Flow Rate 383
14.3.3 Flooding of the Vapor Tube 384
14.3.4 Swelling of the Reaction Mass 385
14.3.5 Practical Procedure for the Assessment of Reactor Safety at the Boiling Point 386
14.4 Dynamics of the Temperature Control System and Process Design 388
14.4.1 Background 388
14.4.2 Modeling the Dynamic Behavior of Industrial Reactors 389
14.4.3 Experimental Simulation of Industrial Reactors 390
14.5 Exercises 391
References 395
15 Risk Reducing Measures 397
15.1 Strategies of Choice 399
15.2 Eliminating Measures 400
15.3 Technical Preventive Measures 401
15.3.1 Control of Feed 401
15.3.2 Emergency Cooling 402
15.3.3 Quenching and Flooding 403
15.3.4 Dumping 404
15.3.5 Controlled Depressurization 405
15.3.6 Alarm Systems 406
15.3.7 Time Factor 407
15.4 Emergency Measures 408
15.4.1 Emergency Pressure Relief Systems 408
15.4.2 Containment 408
15.5 Design of Technical Measures 409
15.5.1 Consequences of Runaway 409
15.5.2 Controllability 412
15.5.3 Assessment of Severity and Probability for the Different Criticality Classes 415
15.6 Exercises 423
References 425
16 Emergency Pressure Relief 427
16.1 General Remarks on Emergency Relief Systems 429
16.1.1 Position of Emergency Relief Systems in a Protection Strategy 429
16.1.2 Regulatory Aspects 429
16.1.3 Protection Devices 430
16.1.4 Sizing Methods 432
16.2 Preliminary Steps of the Sizing Procedure: The Scenario 432
16.2.1 Step 1: Definition of the Design Case 432
16.2.2 Step 1: Quantifying the Relief Scenario 434
16.2.3 Step 2: Determination of the Flow Behavior 437
16.3 Sizing Steps: Fluid Dynamics 439
16.3.1 Step 3: Mass Flow Rate to Be Discharged 439
16.3.2 Step 4: Dischargeable Mass Flux Through an Ideal Nozzle 441
16.3.3 Step 5 for Bursting Disk: Correction for Friction Losses 442
16.3.4 Step 6 for Bursting Disk: Calculation of the Required Relief Area 444
16.3.5 Step 5 for Safety Valve: Calculation of the Required Relief Area 444
16.3.6 Step 6 for SV: Checking Function Stability 445
16.4 Sizing ERS for Multipurpose Reactors 446
16.4.1 Principle of Sizing Procedure 446
16.4.2 Choice of the Sizing Scenario 447
16.4.3 Sensitivity Analysis of the Design Data 447
16.4.4 Checking the Relief Capacity 449
16.5 Effluent Treatment 450
16.5.1 Initial Design Step 451
16.5.2 Total Containment 451
16.5.3 Passive Condenser 451
16.5.4 Catch Tank, Gravity Separator 452
16.5.5 Cyclone 452
16.5.6 Quench Tank 452
16.6 Exercises 452
References 458
17 Reliability of Risk Reducing Measures 461
17.1 Basics of Reliability Engineering 463
17.1.1 Definitions 463
17.1.2 Failure Frequency 465
17.1.3 Failures on the Time Scale 467
17.2 Reliability of Process Control Systems 468
17.2.1 Safety Integrity Level 468
17.2.2 Control Loops 468
17.2.3 Increasing the Reliability of an SIS 469
17.3 Practice of Reliability Assessment 469
17.3.1 Scenario Structure 469
17.3.2 Risk Matrix 470
17.3.3 Risk Reduction 471
17.3.4 Other Methods for Reliability Analysis 473
17.4 Exercises 475
References 476
18 Development of Safe Processes 479
18.1 Inherently Safer Processes 480
18.1.1 Principles of Inherent Safety 480
18.1.2 Safety Along Life Cycle of a Process 482
18.1.3 Developing a Safe Process 483
18.2 Methodological Approach 484
18.2.1 Specificity of the Fine Chemicals Industry 484
18.2.2 Integrated Process Development 484
18.3 Practice of Integrated Process Development 485
18.3.1 Objectives and Data 485
18.3.2 Chemists and Engineers 487
18.3.3 Communication and Problem Solving 488
18.4 Concluding Remark 488
References 489
Solutions of Exercises 491
Symbols 529
Index 537
