Details

Thermal Safety of Chemical Processes


Thermal Safety of Chemical Processes

Risk Assessment and Process Design
2. Aufl.

von: Francis Stoessel

133,99 €

Verlag: Wiley-VCH
Format: EPUB
Veröffentl.: 16.03.2020
ISBN/EAN: 9783527696925
Sprache: englisch
Anzahl Seiten: 574

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Beschreibungen

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.
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
Professor Francis Stoessel is Head of Chemical Process Safety Consulting in the Swissi Process Safety GmbH. After graduating in Chemical Engineering from the Universite de Haute Alsace, he spent most of his career working for Ciba-Geigy in their Chemical Engineering Department. He was Head of the Thermal Safety Department at Ciba, later of Process Safety Consulting at Novartis. He then took up a professorship at the Swiss Federal Institute of Technology at Lausanne. Prof. Stoessel has received awards from the Swiss Expert Commission for Safety in the Chemical Industry and the Swiss Society for Thermal Analysis and Calorimetry.

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