Process Intensification Technologies for Green Chemistry: Engineering Solutions for Sustainable Chemical Processing

The successful implementation of greener chemical processes relies not only on the development of more efficient catalysts for synthetic chemistry but also, and as importantly, on the development of reactor and separation technologies which can deliver enhanced processing performance in a safe, cost-effective and energy efficient manner. Process intensification has emerged as a promising field which can effectively tackle the challenges of significant process enhancement, whilst also offering the potential to diminish the environmental impact presented by the chemical industry. Following an introduction to process intensification and the principles of green chemistry, this book presents a number of intensified technologies which have been researched and developed, including case studies to illustrate their application to green chemical processes. Topics covered include: • Intensified reactor technologies: spinning disc reactors, microreactors, monolith reactors, oscillatory flow reactors, cavitational reactors • Combined reactor/separator systems: membrane reactors, reactive distillation, reactive extraction, reactive absorption • Membrane separations for green chemistry • Industry relevance of process intensification, including economics and environmental impact, opportunities for energy saving, and practical considerations for industrial implementation. Process Intensification for Green Chemistry is a valuable resource for practising engineers and chemists alike who are interested in applying intensified reactor and/or separator systems in a range of industries to achieve green chemistry principles.

Table of Contents:
List of Contributors xiii Preface xv 1 Process Intensification: An Overview of Principles and Practice 1 Kamelia Boodhoo and Adam Harvey 1.1 Introduction 1 1.2 Process Intensification: Definition and Concept 2 1.3 Fundamentals of Chemical Engineering Operations 3 1.3.1 Reaction Engineering 3 1.3.2 Mixing Principles 5 1.3.3 Transport Processes 8 1.4 Intensification Techniques 11 1.4.1 Enhanced Transport Processes 11 1.4.2 Integrating Process Steps 19 1.4.3 Moving from Batch to Continuous Processing 20 1.5 Merits of PI Technologies 21 1.5.1 Business 22 1.5.2 Process 22 1.5.3 Environment 23 1.6 Challenges to Implementation of PI 24 1.7 Conclusion 25 Nomenclature 26 Greek Letters 26 References 27 2 Green Chemistry Principles 33 James Clark, Duncan Macquarrie, Mark Gronnow and Vitaly Budarin 2.1 Introduction 33 2.1.1 Sustainable Development and Green Chemistry 35 2.2 The Twelve Principles of Green Chemistry 35 2.2.1 Ideals of Green Chemistry 36 2.3 Metrics for Chemistry 37 2.3.1 Effective Mass Yield 38 2.3.2 Carbon Efficiency 38 2.3.3 Atom Economy 38 2.3.4 Reaction Mass Efficiency 39 2.3.5 Environmental (E) Factor 39 2.3.6 Comparison of Metrics 40 2.4 Catalysis and Green Chemistry 41 2.4.1 Case Study: Silica as a Catalyst for Amide Formation 43 2.4.2 Case Study: Mesoporous Carbonaceous Material as a Catalyst Support 45 2.5 Renewable Feedstocks and Biocatalysis 46 2.5.1 Case Study: Wheat Straw Biorefinery 48 2.6 An Overview of Green Chemical Processing Technologies 50 2.6.1 Alternative Reaction Solvents for Green Processing 50 2.6.2 Alternative Energy Reactors for Green Chemistry 52 2.7 Conclusion 55 References 55 3 Spinning Disc Reactor: Continuous Thin-film Flow Processing for Green Chemistry Applications 59 Kamelia Boodhoo 3.1 Introduction 59 3.2 Design and Operating Features of SDRs 60 3.2.1 Hydrodynamics 63 3.2.2 SDR Scale-up Strategies 64 3.3 Characteristics of SDRs 66 3.3.1 Thin-film Flow and Surface Waves 66 3.3.2 Heat and Mass Transfer 68 3.3.3 Mixing Characteristics 71 3.3.4 Residence Time and Residence Time Distribution 72 3.3.5 SDR Applications 75 3.4 Case Studies: SDR Application for Green Chemical Processing and Synthesis 76 3.4.1 Cationic Polymerization using Heterogeneous Lewis Acid Catalysts 76 3.4.2 Solvent-free Photopolymerization Processing 78 3.4.3 Heterogeneous Catalytic Organic Reaction in the SDR: An Example of Application to the Pharmaceutical/Fine Chemicals Industry 80 3.4.4 Green Synthesis of Nanoparticles 83 3.5 Hurdles to Industry Implementation 84 3.5.1 Control, Monitoring and Modelling of SDR Processes 84 3.5.2 Limited Process Throughputs 86 3.5.3 Cost and Availability of Equipment 86 3.5.4 Lack of Awareness of SDR Technology 86 3.6 Conclusion 86 Nomenclature 87 Greek Letters 87 Subscripts 87 References 87 4 Micro Process Technology and Novel Process Windows – Three Intensification Fields 91 Svetlana Borukhova and Volker Hessel 4.1 Introduction 91 4.2 Transport Intensification 93 4.2.1 Fundamentals 93 4.2.2 Mixing Principles 94 4.2.3 Micromixers 96 4.2.4 Micro Heat Exchangers 102 4.2.5 Exothermic Reactions as Major Application Examples 106 4.3 Chemical Intensification 108 4.3.1 Fundamentals 108 4.3.2 New Chemical Transformations 108 4.3.3 High Temperature 118 4.3.4 High Pressure 122 4.3.5 Alternative Reaction Media 124 4.4 Process Design Intensification 128 4.4.1 Fundamentals 128 4.4.2 Large-scale Manufacture of Adipic Acid – A Full Process Design Vision in Flow 130 4.4.3 Process Integration – From Single Operation towards Full Process Design 131 4.4.4 Process Simplification 135 4.5 Industrial Microreactor Process Development 137 4.5.1 Industrial Demonstration of Specialty/Pharma Chemistry Flow Processing 138 4.5.2 Industrial Demonstration of Fine Chemistry Flow Processing 138 4.5.3 Industrial Demonstration of Bulk Chemistry Flow Processing 139 4.6 Conclusion 140 Acknowledgement 141 References 141 5 Green Chemistry in Oscillatory Baffled Reactors 157 Adam Harvey 5.1 Introduction 157 5.1.1 Continuous versus Batch Operation 157 5.1.2 The Oscillatory Baffled Reactor’s ‘Niche’ 157 5.2 Case Studies: OBR Green Chemistry 164 5.2.1 A Saponification Reaction 164 5.2.2 A Three-phase Reaction with Photoactivation for Oxidation of Waste Water Contaminants 166 5.2.3 ‘Mesoscale’ OBRs 168 5.3 Conclusion 170 References 172 6 Monolith Reactors for Intensified Processing in Green Chemistry 175 Joseph Wood 6.1 Introduction 175 6.2 Design of Monolith Reactors 176 6.2.1 Monolith and Washcoat Design 176 6.2.2 Reactor and Distributor Design 178 6.3 Hydrodynamics of Monolith Reactors 179 6.3.1 Flow Regimes 179 6.3.2 Mixing and Mass Transfer 180 6.4 Advantages of Monolith Reactors 182 6.4.1 Scale-out, Not Scale-up? 182 6.4.2 PI for Green Chemistry 183 6.5 Applications in Green Chemistry 185 6.5.1 Chemical and Fine Chemical Industry 185 6.5.2 Cleaner Production of Fuels 187 6.5.3 Removal of Toxic Emissions 188 6.6 Conclusion 192 Acknowledgement 193 Nomenclature 193 Greek Letters 193 Subscripts and Superscripts 193 References 193 7 Process Intensification and Green Processing Using Cavitational Reactors 199 Vijayanand Moholkar, Parag Gogate and Aniruddha Pandit 7.1 Introduction 199 7.2 Mechanism of Cavitation-based PI of Chemical Processing 200 7.3 Reactor Configurations 201 7.3.1 Sonochemical Reactors 201 7.3.2 Hydrodynamic Cavitation Reactors 205 7.4 Mathematical Modelling 207 7.5 Optimization of Operating Parameters in Cavitational Reactors 209 7.5.1 Sonochemical Reactors 209 7.5.2 Hydrodynamic Cavitation Reactors 210 7.6 Intensification of Cavitational Activity 211 7.6.1 Use of PI Parameters 212 7.6.2 Use of a Combination of Cavitation and Other Processes 213 7.7 Case Studies: Intensification of Chemical Synthesis using Cavitation 214 7.7.1 Transesterification of Vegetable Oils Using Alcohol 214 7.7.2 Selective Synthesis of Sulfoxides from Sulfides Using Sonochemical Reactors 217 7.8 Overview of Intensification and Green Processing Using Cavitational Reactors 218 7.9 The Future 221 7.10 Conclusion 222 References 222 8 Membrane Bioreactors for Green Processing in a Sustainable Production System 227 Rosalinda Mazzei, Emma Piacentini, Enrico Drioli and Lidietta Giorno 8.1 Introduction 227 8.2 Membrane Bioreactors 228 8.2.1 Membrane Bioreactors with Biocatalyst Recycled in the Retentate Stream 228 8.2.2 Membrane Bioreactors with Biocatalyst Segregated in the Membrane Module Space 230 8.3 Biocatalytic Membrane Reactors 230 8.3.1 Entrapment 230 8.3.2 Gelification 231 8.3.3 Chemical Attachment 231 8.4 Case Studies: Membrane Bioreactors 232 8.4.1 Biofuel Production Using Enzymatic Transesterification 233 8.4.2 Waste Water Treatment and Reuse 237 8.4.3 Waste Valorization to Produce High-added-value Compounds 239 8.5 Green Processing Impact of Membrane Bioreactors 245 8.6 Conclusion 247 References 247 9 Reactive Distillation 251 Anton Kiss 9.1 Introduction 251 9.2 Principles of RD 252 9.3 Design, Control and Applications 253 9.4 Modelling RD 256 9.5 Economical and Technical Evaluation 257 9.5.1 Economical Evaluation 257 9.5.2 Technical Evaluation 260 9.6 Case Studies: RD 261 9.6.1 Biodiesel Production by Heat-Integrated RD 261 9.6.2 Fatty Ester Synthesis by Dual RD 267 9.7 Green Processing Impact of RD 270 9.8 Conclusion 271 References 271 10 Reactive Extraction Technology 275 Keat T. Lee and Steven Lim 10.1 Introduction 275 10.1.1 Definition and Description 275 10.1.2 Literature Review 276 10.2 Case Studies: Reactive Extraction Technology 277 10.2.1 Reactive Extraction for the Synthesis of FAME from Jatropha curcas L. Seeds 277 10.2.2 Supercritical Reactive Extraction for FAME Synthesis from Jatropha curcas L. Seeds 281 10.3 Impact on Green Processing and Process Intensification 284 10.4 Conclusion 286 References 286 11 Reactive Absorption 289 Anton A. Kiss 11.1 Introduction 289 11.2 Theory and Models 290 11.2.1 Equilibrium Stage Model 290 11.2.2 HTU/NTU Concepts and Enhancement Factors 291 11.2.3 Rate-based Stage Model 291 11.3 Equipment, Operation and Control 291 11.4 Applications in Gas Purification 293 11.4.1 Carbon Dioxide Capture 293 11.4.2 Sour Gas Treatment 296 11.4.3 Removal of Nitrogen Oxides 296 11.4.4 Desulfurization 297 11.4.5 Sulfuric Acid Production 299 11.4.6 Nitric Acid Production 299 11.4.7 Biodiesel and Fatty Esters Synthesis 302 11.5 Green Processing Impact of RA 307 11.6 Challenges and Future Prospects 307 References 307 12 Membrane Separations for Green Chemistry 311 Rosalinda Mazzei, Emma Piacentini, Enrico Drioli and Lidietta Giorno 12.1 Introduction 311 12.2 Membranes and Membrane Processes 312 12.3 Case Studies: Membrane Operations in Green Processes 318 12.3.1 Membrane Technology in Metal Ion Removal from Waste Water 318 12.3.2 Membrane Operations in Acid Separation from Waste Water 330 12.3.3 Membrane Operation for Hydrocarbon Separation from Waste Water 333 12.3.4 Membrane Operations for the Production of Optically Pure Enantiomers 336 12.4 Integrated Membrane Processes 342 12.4.1 Integrated Membrane Processes for Water Desalination 342 12.4.2 Integrated Membrane Processes for the Fruit Juice Industry 343 12.5 Green Processing Impact of Membrane Processes 344 12.6 Conclusion 347 References 347 13 Process Intensification in a Business Context: General Considerations 355 Dag Eimer and Nils Eldrup 13.1 Introduction 355 13.2 The Industrial Setting 356 13.3 Process Case Study 358 13.3.1 Essential Lessons 364 13.4 Business Risk and Ideas 366 13.5 Conclusion 367 References 367 14 Process Economics and Environmental Impacts of Process Intensification in the Petrochemicals, Fine Chemicals and Pharmaceuticals Industries 369 Jan Harmsen 14.1 Introduction 369 14.2 Petrochemicals Industry 370 14.2.1 Drivers for Innovation 370 14.2.2 Conventional Technologies Used 372 14.2.3 Commercially Applied PI Technologies 372 14.3 Fine Chemicals and Pharmaceuticals Industries 376 14.3.1 Drivers for Innovation 376 14.3.2 Conventional Technologies Used 377 14.3.3 Commercially Applied PI Technologies 377 References 377 15 Opportunities for Energy Saving from Intensified Process Technologies in the Chemical and Processing Industries 379 Dena Ghiasy and Kamelia Boodhoo 15.1 Introduction 379 15.2 Energy-Intensive Processes in UK Chemical and Processing Industries 380 15.2.1 What Can PI Offer? 380 15.3 Case Study: Assessment of the Energy Saving Potential of SDR Technology 383 15.3.1 Basis for Comparison 384 15.3.2 Batch Process Energy Usage 384 15.3.3 Batch/SDR Combined Energy Usage 386 15.3.4 Energy Savings 389 15.4 Conclusion 389 Nomenclature 390 Greek Letters 390 Subscripts 390 Appendix: Physical Properties of Styrene, Toluene and Cooling/Heating Fluids 391 References 391 16 Implementation of Process Intensification in Industry 393 Jan Harmsen 16.1 Introduction 393 16.2 Practical Considerations for Commercial Implementation 393 16.2.1 Reactive Distillation 394 16.2.2 Dividing Wall Column Distillation 396 16.2.3 Reverse Flow Reactors 396 16.2.4 Microreactors 397 16.2.5 Rotating Packed Bed Reactors 397 16.3 Scope for Implementation in Various Process Industries 397 16.3.1 Oil Refining and Bulk Chemicals 397 16.3.2 Fine Chemicals and Pharmaceuticals Industries 398 16.3.3 Biomass Conversion 399 16.4 Future Prospects 399 References 399 Index 401

About the Author :
Dr Kamelia Boodhoo, Newcastle University, UK. Dr Boodhoo's research in the area of Process Intensification focuses on the development of centrifugal field reactors with particular emphasis on Spinning Disc Reactors. She also has a keen interest in intensification applications involving green chemistry and engineering and renewable resources such as the use of biomass for biopolymers. Dr Boodhoo has been involved in designing and delivering a specialist module on Process Intensification targeted at final year MEng students and MSc students at Newcastle University. For the last two years, she has also been a guest lecturer on the MSc in Green Chemistry and Sustainable Industrial Technology programme at the University of York, teaching "Improved Reactor Designs through Process intensification". Dr Adam Harvey, Newcastle University, UK. Dr Harvey is an active member of the Process Intensification Group at Newcastle. He is a member of the steering committee of the international research network "Process Intensification Network" and co-author of "Process Intensification", published in 2008. He currently lectures on Oscillatory Flow Reactors as part of the Process Intensification module delivered to final year MEng and MSc students.