Multiphase Catalytic Reactors

Zeynep Ilsen Önsan received her B.Sc degree (1968) in chemical engineering from former Robert College (now Bogazici University), Istanbul-Turkey, and her Ph.D. degree and D.I.C. (1972) in chemical engineering and heterogeneous catalysis from Imperial College, London-UK. She pioneered in establishing heterogeneous catalysis research in Turkey at Bogazici University, directed several sizeable research and institution-building projects, and has 40 years of teaching and research experience in heterogeneous catalysis and chemical reaction engineering and 25 years of research collaboration and teaching in bioreaction engineering. Dr. Önsan is a professor of chemical engineering at Bogazici University and has 85 research papers including 74 articles in SCI journals and a book chapter coauthored with Dr. Avci on reactor design for fuel processing. Ahmet Kerim Avci received BS, MS and PhD degrees in chemical engineering from Bogazici University in 1996, 1997 and 2003, respectively. He worked as an R&D manager in Procter & Gamble, Brussels-Belgium. In 2005, he joined chemical engineering department of Bogazici University, where he is currently a full professor. He is the leader of numerous research projects funded by governmental institutes and industry, and is the author of more than 25 papers in refereed SCI journals. He is the holder of Distinguished Young Scientist Fellowship (Turkish Academy of Sciences, 2009), Excellence in Research Award (Bogazici University Foundation, 2010), Eser Tumen Outstanding Achievement Award for Young Scientists (2011) and Professor Mustafa N. Parlar Research Incentive Award (2011).

List of Contributors, x

Preface, xii

Part 1 Principles of catalytic reaction engineering

1 Catalytic reactor types and their industrial significance, 3
Zeynep Ilsen Önsan and Ahmet Kerim Avci

1.1 Introduction, 3

1.2 Reactors with fixed bed of catalysts, 3

1.2.1 Packed-bed reactors, 3

1.2.2 Monolith reactors, 8

1.2.3 Radial flow reactors, 9

1.2.4 Trickle-bed reactors, 9

1.2.5 Short contact time reactors, 10

1.3 Reactors with moving bed of catalysts, 11

1.3.1 Fluidized-bed reactors, 11

1.3.2 Slurry reactors, 13

1.3.3 Moving-bed reactors, 14

1.4 Reactors without a catalyst bed, 14

1.5 Summary, 16

References, 16

2 Microkinetic analysis of heterogeneous catalytic systems, 17
Zeynep Ilsen Önsan

2.1 Heterogeneous catalytic systems, 17

2.1.1 Chemical and physical characteristics of solid catalysts, 18

2.1.2 Activity, selectivity, and stability, 21

2.2 Intrinsic kinetics of heterogeneous reactions, 22

2.2.1 Kinetic models and mechanisms, 23

2.2.2 Analysis and correlation of rate data, 27

2.3 External (interphase) transport processes, 32

2.3.1 External mass transfer: Isothermal conditions, 33

2.3.2 External temperature effects, 35

2.3.3 Nonisothermal conditions: Multiple steady states, 36

2.3.4 External effectiveness factors, 38

2.4 Internal (intraparticle) transport processes, 39

2.4.1 Intraparticle mass and heat transfer, 39

2.4.2 Mass transfer with chemical reaction: Isothermal effectiveness, 41

2.4.3 Heat and mass transfer with chemical reaction, 45

2.4.4 Impact of internal transport limitations on kinetic studies, 47

2.5 Combination of external and internal transport effects, 48

2.5.1 Isothermal overall effectiveness, 48

2.5.2 Nonisothermal conditions, 49

2.6 Summary, 50

Nomenclature, 50

Greek letters, 51

References, 51

Part 2 Two-phase catalytic reactors

3 Fixed-bed gas–solid catalytic reactors, 55
João P. Lopes and Alírio E. Rodrigues

3.1 Introduction and outline, 55

3.2 Modeling of fixed-bed reactors, 57

3.2.1 Description of transport–reaction phenomena, 57

3.2.2 Mathematical model, 59

3.2.3 Model reduction and selection, 61

3.3 Averaging over the catalyst particle, 61

3.3.1 Chemical regime, 64

3.3.2 Diffusional regime, 64

3.4 Dominant fluid–solid mass transfer, 66

3.4.1 Isothermal axial flow bed, 67

3.4.2 Non-isothermal non-adiabatic axial flow bed, 70

3.5 Dominant fluid–solid mass and heat transfer, 70

3.6 Negligible mass and thermal dispersion, 72

3.7 Conclusions, 73

Nomenclature, 74

Greek letters, 75

References, 75

4 Fluidized-bed catalytic reactors, 80
John R. Grace

4.1 Introduction, 80

4.1.1 Advantages and disadvantages of fluidized-bed reactors, 80

4.1.2 Preconditions for successful fluidized-bed processes, 81

4.1.3 Industrial catalytic processes employing fluidized-bed reactors, 82

4.2 Key hydrodynamic features of gas-fluidized beds, 83

4.2.1 Minimum fluidization velocity, 83

4.2.2 Powder group and minimum bubbling velocity, 84

4.2.3 Flow regimes and transitions, 84

4.2.4 Bubbling fluidized beds, 84

4.2.5 Turbulent fluidization flow regime, 85

4.2.6 Fast fluidization and dense suspension upflow, 85

4.3 Key properties affecting reactor performance, 86

4.3.1 Particle mixing, 86

4.3.2 Gas mixing, 87

4.3.3 Heat transfer and temperature uniformity, 87

4.3.4 Mass transfer, 88

4.3.5 Entrainment, 88

4.3.6 Attrition, 89

4.3.7 Wear, 89

4.3.8 Agglomeration and fouling, 89

4.3.9 Electrostatics and other interparticle forces, 89

4.4 Reactor modeling, 89

4.4.1 Basis for reactor modeling, 89

4.4.2 Modeling of bubbling and slugging flow regimes, 90

4.4.3 Modeling of reactors operating in high-velocity flow regimes, 91

4.5 Scale-up, pilot testing, and practical issues, 91

4.5.1 Scale-up issues, 91

4.5.2 Laboratory and pilot testing, 91

4.5.3 Instrumentation, 92

4.5.4 Other practical issues, 92

4.6 Concluding remarks, 92

Nomenclature, 93

Greek letters, 93

References, 93

Part 3 Three-phase catalytic reactors

5 Three-phase fixed-bed reactors, 97
Ion Iliuta and Faïçal Larachi

5.1 Introduction, 97

5.2 Hydrodynamic aspects of three-phase fixed-bed reactors, 98

5.2.1 General aspects: Flow regimes, liquid holdup, two-phase pressure drop, and wetting efficiency, 98

5.2.2 Standard two-fluid models for two-phase downflow and upflow in three-phase fixed-bed reactors, 100

5.2.3 Nonequilibrium thermomechanical models for two-phase flow in three-phase fixed-bed reactors, 102

5.3 Mass and heat transfer in three-phase fixed-bed reactors, 104

5.3.1 Gas–liquid mass transfer, 105

5.3.2 Liquid–solid mass transfer, 105

5.3.3 Heat transfer, 106

5.4 Scale-up and scale-down of trickle-bed reactors, 108

5.4.1 Scaling up of trickle-bed reactors, 108

5.4.2 Scaling down of trickle-bed reactors, 109

5.4.3 Salient conclusions, 110

5.5 Trickle-bed reactor/bioreactor modeling, 110

5.5.1 Catalytic hydrodesulfurization and bed clogging in hydrotreating trickle-bed reactors, 110

5.5.2 Biomass accumulation and clogging in trickle-bed bioreactors for phenol biodegradation, 115

5.5.3 Integrated aqueous-phase glycerol reforming and dimethyl ether synthesis into an allothermal dual-bed reactor, 121

Nomenclature, 126

Greek letters, 127

Subscripts, 128

Superscripts, 128

Abbreviations, 128

References, 128

6 Three-phase slurry reactors, 132
Vivek V. Buwa, Shantanu Roy and Vivek V. Ranade

6.1 Introduction, 132

6.2 Reactor design, scale-up methodology, and reactor selection, 134

6.2.1 Practical aspects of reactor design and scale-up, 134

6.2.2 Transport effects at particle level, 139

6.3 Reactor models for design and scale-up, 143

6.3.1 Lower order models, 143

6.3.2 Tank-in-series/mixing cell models, 144

6.4 Estimation of transport and hydrodynamic parameters, 145

6.4.1 Estimation of transport parameters, 145

6.4.2 Estimation of hydrodynamic parameters, 146

6.5 Advanced computational fluid dynamics (CFD)-based models, 147

6.6 Summary and closing remarks, 149

Acknowledgments, 152

Nomenclature, 152

Greek letters, 153

Subscripts, 153

References, 153

7 Bioreactors, 156
Pedro Fernandes and Joaquim M.S. Cabral

7.1 Introduction, 156

7.2 Basic concepts, configurations, and modes of operation, 156

7.2.1 Basic concepts, 156

7.2.2 Reactor configurations and modes of operation, 157

7.3 Mass balances and reactor equations, 159

7.3.1 Operation with enzymes, 159

7.3.2 Operation with living cells, 160

7.4 Immobilized enzymes and cells, 164

7.4.1 Mass transfer effects, 164

7.4.2 Deactivation effects, 166

7.5 Aeration, 166

7.6 Mixing, 166

7.7 Heat transfer, 167

7.8 Scale-up, 167

7.9 Bioreactors for animal cell cultures, 167

7.10 Monitoring and control of bioreactors, 168

Nomenclature, 168

Greek letters, 169

Subscripts, 169

References, 169

Part 4 Structured reactors

8 Monolith reactors, 173
João P. Lopes and Alírio E. Rodrigues

8.1 Introduction, 173

8.1.1 Design concepts, 174

8.1.2 Applications, 178

8.2 Design of wall-coated monolith channels, 179

8.2.1 Flow in monolithic channels, 179

8.2.2 Mass transfer and wall reaction, 182

8.2.3 Reaction and diffusion in the catalytic washcoat, 190

8.2.4 Nonisothermal operation, 194

8.3 Mapping and evaluation of operating regimes, 197

8.3.1 Diversity in the operation of a monolith reactor, 197

8.3.2 Definition of operating regimes, 199

8.3.3 Operating diagrams for linear kinetics, 201

8.3.4 Influence of nonlinear reaction kinetics, 202

8.3.5 Performance evaluation, 203

8.4 Three-phase processes, 204

8.5 Conclusions, 207

Nomenclature, 207

Greek letters, 208

Superscripts, 208

Subscripts, 208

References, 209

9 Microreactors for catalytic reactions, 213
Evgeny Rebrov and Sourav Chatterjee

9.1 Introduction, 213

9.2 Single-phase catalytic microreactors, 213

9.2.1 Residence time distribution, 213

9.2.2 Effect of flow maldistribution, 214

9.2.3 Mass transfer, 215

9.2.4 Heat transfer, 215

9.3 Multiphase microreactors, 216

9.3.1 Microstructured packed beds, 216

9.3.2 Microchannel reactors, 218

9.4 Conclusions and outlook, 225

Nomenclature, 226

Greek letters, 227

Subscripts, 227

References, 228

Part 5 Essential tools of reactor modeling and design

10 Experimental methods for the determination of parameters, 233
Rebecca R. Fushimi, John T. Gleaves and Gregory S. Yablonsky

10.1 Introduction, 233

10.2 Consideration of kinetic objectives, 234

10.3 Criteria for collecting kinetic data, 234

10.4 Experimental methods, 234

10.4.1 Steady-state flow experiments, 235

10.4.2 Transient flow experiments, 237

10.4.3 Surface science experiments, 238

10.5 Microkinetic approach to kinetic analysis, 241

10.6 TAP approach to kinetic analysis, 241

10.6.1 TAP experiment design, 242

10.6.2 TAP experimental results, 244

10.7 Conclusions, 248

References, 249

11 Numerical solution techniques, 253
Ahmet Kerim Avci and Seda Keskin

11.1 Techniques for the numerical solution of ordinary differential equations, 253

11.1.1 Explicit techniques, 253

11.1.2 Implicit techniques, 254

11.2 Techniques for the numerical solution of partial differential equations, 255

11.3 Computational fluid dynamics techniques, 256

11.3.1 Methodology of computational fluid dynamics, 256

11.3.2 Finite element method, 256

11.3.3 Finite volume method, 258

11.4 Case studies, 259

11.4.1 Indirect partial oxidation of methane in a catalytic tubular reactor, 259

11.4.2 Hydrocarbon steam reforming in spatially segregated microchannel reactors, 261

11.5 Summary, 265

Nomenclature, 266

Greek letters, 267

Subscripts/superscripts, 267

References, 267

Part 6 Industrial applications of multiphase reactors

12 Reactor approaches for Fischer–Tropsch synthesis, 271
Gary Jacobs and Burtron H. Davis

12.1 Introduction, 271

12.2 Reactors to 1950, 272

12.3 1950–1985 period, 274

12.4 1985 to present, 276

12.4.1 Fixed-bed reactors, 276

12.4.2 Fluidized-bed reactors, 280

12.4.3 Slurry bubble column reactors, 281

12.4.4 Structured packings, 286

12.4.5 Operation at supercritical conditions (SCF), 288

12.5 The future?, 288

References, 291

13 Hydrotreating of oil fractions, 295
Jorge Ancheyta, Anton Alvarez-Majmutov and Carolina Leyva

13.1 Introduction, 295

13.2 The HDT process, 296

13.2.1 Overview, 296

13.2.2 Role in petroleum refining, 297

13.2.3 World outlook and the situation of Mexico, 298

13.3 Fundamentals of HDT, 300

13.3.1 Chemistry, 300

13.3.2 Reaction kinetics, 303

13.3.3 Thermodynamics, 305

13.3.4 Catalysts, 306

13.4 Process aspects of HDT, 307

13.4.1 Process variables, 307

13.4.2 Reactors for hydroprocessing, 310

13.4.3 Catalyst activation in commercial hydrotreaters, 316

13.5 Reactor modeling and simulation, 317

13.5.1 Process description, 317

13.5.2 Summary of experiments, 317

13.5.3 Modeling approach, 319

13.5.4 Simulation of the bench-scale unit, 320

13.5.5 Scale-up of bench-unit data, 323

13.5.6 Simulation of the commercial unit, 324

Nomenclature, 326

Greek letters, 327

Subscripts, 327

Non-SI units, 327

References, 327

14 Catalytic reactors for fuel processing, 330
Gunther Kolb

14.1 Introduction—The basic reactions of fuel processing, 330

14.2 Theoretical aspects, advantages, and drawbacks of fixed beds versus monoliths, microreactors, and membrane reactors, 331

14.3 Reactor design and fabrication, 332

14.3.1 Fixed-bed reactors, 332

14.3.2 Monolithic reactors, 332

14.3.3 Microreactors, 332

14.3.4 Membrane reactors, 333

14.4 Reformers, 333

14.4.1 Fixed-bed reformers, 336

14.4.2 Monolithic reformers, 337

14.4.3 Plate heat exchangers and microstructured reformers, 342

14.4.4 Membrane reformers, 344

14.5 Water-gas shift reactors, 348

14.5.1 Monolithic reactors, 348

14.5.2 Plate heat exchangers and microstructured water-gas shift reactors, 348

14.5.3 Water-gas shift in membrane reactors, 350

14.6 Carbon monoxide fine cleanup: Preferential oxidation and selective methanation, 350

14.6.1 Fixed-bed reactors, 352

14.6.2 Monolithic reactors, 352

14.6.3 Plate heat exchangers and microstructured reactors, 353

14.7 Examples of complete fuel processors, 355

14.7.1 Monolithic fuel processors, 355

14.7.2 Plate heat exchanger fuel processors on the meso- and microscale, 357

Nomenclature, 359

References, 359

15 Modeling of the catalytic deoxygenation of fatty acids in a packed bed reactor, 365
Teuvo Kilpiö, Päivi Mäki-Arvela, Tapio Salmi and Dmitry Yu. Murzin

15.1 Introduction, 365

15.2 Experimental data for stearic acid deoxygenation, 366

15.3 Assumptions, 366

15.4 Model equations, 367

15.5 Evaluation of the adsorption parameters, 368

15.6 Particle diffusion study, 369

15.7 Parameter sensitivity studies, 369

15.8 Parameter identification studies, 370

15.9 Studies concerning the deviation from ideal plug flow conditions, 371

15.10 Parameter estimation results, 372

15.11 Scale-up considerations, 372

15.12 Conclusions, 375

Acknowledgments, 375

Nomenclature, 375

Greek letters, 375

References, 376

Index, 377