Con tents

PREFACE TO THIRD EDITION

PREFACE TO SECOND EDITION

PREFACE TO FIRST EDITION

ACKNOWLEDGEMENTS

LIST OF CONTRIBUTORS

xiii

1. Reactor Design-General Principles 1.1 Basic objectives in design of a reactor

1.1.1 Byproducts and their economic importance 1.1.2 Preliminary appraisal of a reactor project Classification of reactors and choice of reactor type 1.2.1 Homogeneous and heterogeneous reactors I .2.2 Batch reactors and continuous reactors 1.2.3 Variations in contacting pattern-semi-batch operation 1.2.4 Influence of heat of reaction on reactor type

1.3.1 Chemical equilibria and chemical kinetics I .3.2 Calculation of equilibrium conversion 1.3.3 Ultimate choice of reactor conditions

1.4 Chemical kinetics and rate equations 1.4.1 Definition of reaction rate, order of reaction and rate constant 1.4.2 Influence of temperature. Activation energy I .4.3 Rate equations and reaction mechanism 1.4.4 Reversible reactions 1.4.5 Rate equations for constant-volume batch reactors 1.4.6 Experimental determination of kinetic constants

1.5 General material and thermal balances 1.6 Batch reactors

1.6.1 Calculation of reaction time; basic design equation 1.6.2 Reaction time-isothermal operation I .6.3 Maximum production rate 1.6.4 Reaction time-non-isothermal operation 1.6.5 Adiabatic operation

1.7.1 Basic design equations for a tubular reactor 1.7.2 Tubular reactors-non-isothermal operation 1.7.3 Pressure drop in tubular reactors 1.7.4 Kinetic data from tubular reactors

1.2

1.3 Choice of process conditions

I .7 Tubular-flow reactors

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10 10 1 1 14 15 16 17 18 20 21 24 24 27 27 28 30 31 32 34 36 40 41 42

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vi CONTENTS

1.8 Continuous stirred-tank reactors 1.8.1 1.8.2 1.8.3 Graphical methods 1.8.4 Autothermal operation 1.8.5

1.9 Comparison of batch, tubular and stirred-tank reactors for a single reaction. Reactor output 1.9.1 1.9.2 Continuous stirred-tank reactor 1.9.3 Comparison of reactors

reactions. Reactor yield 1.10.1 Types of multiple reactions 1.10.2 Yield and selectivity 1.10.3 Reactor type and backmixing 1.10.4 Reactions in parallel 1.10.5 Reactions in parallel-two reactants 1.10.6 Reactions in series 1.10.7 Reactions in series-two reactants

Assumption of ideal mixing. Residence time Design equations for continuous stirred-tank reactors

Kinetic data from continuous stirred-tank reactors

Batch reactor and tubular plug-flow reactor

1.10 Comparison of batch, tubular and stirred-tank reactors for multiple

1.1 1 Further reading I . 12 References 1.13 Nomenclature

2. Flow Characteristics of Reactors-Flow Modelling 2.1 Non-ideal flow and mixing in chemical reactors

2.1.1 Types of non-ideal flow patterns 2.1.2 Experimental tracer methods 2.1.3 Age distribution of a stream leaving a vessel-E-curves 2.1.4 Application of tracer information to reactors

2.3.1 Axial dispersion and model development 2.3.2 Basic differential equation 2.3.3 Response to an ideal pulse input of tracer 2.3.4 Experimental determination of dispersion coefficient from a pulse input 2.3.5 Further development of tracer injection theory 2.3.6 Values of dispersion coefficients from theory and experiment 2.3.7 Dispersed plug-flow model with first-order chemical reaction 2.3.8 Applications and limitations of the dispersed plug-flow model Models involving combinations of the basic flow elements

2.2 Tanks-in-series model 2.3 Dispersed plug-flow model

2.4 2.5 Further reading 2.6 References 2.7 Nomenclature

3. Gas-Solid Reactions and Reactors 3.1 Introduction 3.2

3.3

Mass transfer within porous solids 3.2.1 The effective diffusivity Chemical reaction in porous catalyst pellets 3.3.1 3.3.2 3.3.3

Isothermal reactions in porous catalyst pellets Effect of intraparticle diffusion on experimental parameters Non-isothermal reactions in Dorous catalvst Dellets

43 43 44 47 49 50

51 52 52 54

55 56 57 57 58 61 63 67 68 68 68

71 71 71 71 73 75 78 80 80 83 84 88 93 96 98

102 104 105 105 106

108 108 111 112 115 116 122 124 < .

3.3.4 Criteria for diffusion control' I28

CONTENTS

3.3.5

3.3.6 Catalyst de-activation and poisoning 3.4 Mass transfer from a fluid stream to a solid surface 3.5 Chemical kinetics of heterogeneous catalytic reactions

3.5.1 Adsorption of a reactant as the rate determining step 3.5.2 Surface reaction as the rate determining step 3.5.3 Desorption of a product as the rate determining step 3.5.4 Rate determining steps for other mechanisms 3.5.5 Examples of rate equations for industrially important reactions

3.6.1 Packed tubular reactors 3.6.2 Thermal characteristics of packed reactors 3.6.3 Fluidised bed reactors

3.7.1 Modelling and design of gas-solid reactors 3.7.2 Single particle unreacted core models 3.7.3 Types of equipment and contacting patterns

3.8 Further reading 3.9 References 3.10 Nomenclature

Selectivity in catalytic reactions influenced by mass and heat transfer effects

3.6 Design calculations

3.7 Gas-solid non-catalytic reactors

vii

4. Gas-Liquid and Gas-Liquid-Solid Reactors 4.1 Gas-liquid reactors

4.1.1 Gas-liquid reactions 4.1.2 Types of reactors 4.1.3 Equations for mass transfer with chemical reaction 4. I .4 Choice of a suitable reactor 4.1.5 Information required for gas-liquid reactor design 4.1.6 Examples of gas-liquid reactors 4.1.7 High aspect-ratio bubble columns and multiple-impeller agitated tanks 4.1.8 Axial dispersion in bubble columns 4.1.9 Laboratory reactors for investigating the kinetics of gas-liquid reactions

4.2. I Gas-liquid-solid reactions 4.2.2 Mass transfer and reaction steps 4.2.3 Gas-liquid-solid reactor types: choosing a reactor 4.2.4 Combination of mass transfer and reaction steps

4.3 Further reading 4.4 References 4.5 Nomenclature

4.2 Gas-liquid-solid reactors

5. Biochemical Reaction Engineering

Cells as reactors The biological world and ecology Biological products and production systems

5.1 Introduction 5. I . 1 5.1.2 5. I .3 5.1.4 Scales of operation

5.2 Cellular diversity and the classification of living systems 5.2.1 Classification 5.2.2 Prokaryotic organisms 5.2.3 Eukaryotic organisms 5.2.4 General physical properties of cells 5.2.5 Tolerance to environmental conditions

129 139 143 144 146 148 148 148 150 151 151 172 180 181 182 183 186 190 190 192

196 196 196 196 197 202 204 205 216 218 223 229 229 230 23 1 235 248 248 249

252 252 254 255 256 257 259 260 262 265 269 270

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5.3 Chemical composition of cells 5.3.1 Elemental composition 5.3.2 Proteins 5.3.3 Physical properties of proteins 5.3.4 Protein purification and separation 5.3.5 Stability of proteins 5.3.6 Nucleic acids 5.3.7 Lipids and membranes 5.3.8 Carbohydrates 5.3.9 Cell walls

5.4 Enzymes 5.4.1 Biological versus chemical reaction processes 5.4.2 Properties of enzymes 5.4.3 Enzyme kinetics 5.4.4 Derivation of the Michaelis-Menten equation 5.4.5 The significance of kinetic constants 5.4.6 The Haldane relationship 5.4.7 Transformations of the Michaelis-Menten equation 5.4.8 Enzyme inhibition 5.4.9 The kinetics of two-substrate reactions 5.4.10 The effects of temperature and pH on enzyme kinetics and enzyme

de-activation. 5.4.1 1 Enzyme de-activation

5.5.1 The roles of metabolism 5.5.2 5.5.3 5.5.4 Energy generation 5.5.5 Substrate level phosphorylation 5.5.6 5.5.7 Photosynthesis

5.6.1 Mutation and mutagenesis 5.6.2 Genetic recombination in bacteria 5.6.3 Genetic engineering 5.6.4 Recombinant DNA technology 5.6.5 Genetically engineered products Cellular control mechanisms and their manipulation 5.7. I The control of enzyme activity 5.7.2 The control of metabolic pathways 5.7.3 The control of protein synthesis

5.8 Stoichiometric aspects of biological processes 5.8.1 Yield

5.9 Microbial growth 5.9.1 5.9.2 Microbial growth kinetics 5.9.3 Product formation

5.10.1 Effect of external diffusion limitation 5.10.2 Effect of internal diffusion limitation

5.1 I . 1 Enzyme reactors 5.11.2 Batch growth of micro-organisms 5.11.3 Continuous culture of micro-organisms

5.12.1 Use of batch culture experiments 5.12.2 Use of continuous culture experiments

5.5 Metabolism

Types of reactions in metabolism Energetic aspects of biological processes

Aerobic respiration and oxidative phosphorylation

5.6 Strain improvement methods

5.7

Phases of growth of a microbial culture

5.10 Immobilised biocatalysts

5.1 1 Reactor configurations

5.12 Estimation of kinetic parameters

27 I 27 1 273 275 277 277 27 8 278 278 278 279 279 279 28 1 282 285 286 28 7 289 29 I

294 29 5 298 298 298 302 304 304 309 315 315 316 318 320 320 325 326 326 327 334 337 339 342 342 345 352 354 356 360 364 364 365 367 386 386 393

CONTENTS

5.13 Non-steady state microbial systems 5.13. I Predator-prey relationships 5.13.2 Structured models

5.14 Further design considerations 5.14.1 Aseptic operation 5.14.2 Aeration 5.14.3 Special aspects of biological reactors

Appendix 5.1 Proteins Appendix 5.2 Nucleic acids Appendix 5.3 Derivation of Michaelis-Menten equation using the

rapid-equilibrium assumption Appendix 5.4 The Haldane relationship Appendix 5.5 Enzyme inhibition Appendix 5.6 Information storage and retrieval in the cell

5.15 Appendices

5.16 Further reading 5.17 References 5.18 Nomenclature

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396 396 398 402 405 405 409 410 410 416

6. Sensors for Measurement and Control 6.1 Introduction 6.2 The measurement of flow

6.2.1 Methods dependent on relationship between pressure drop and flowrate 6.2.2 Further methods of measuring volumetric flow 6.2.3 The measurement of mass flow 6.2.4 The measurement of low flowrates 6.2.5 Open channel flow 6.2.6 Flow profile distortion

6.3 The measurement of pressure 6.3.1 Classification of pressure sensors 6.3.2 Elastic elements 6.3.3 6.3.4 Differential pressure cells 6.3.5 Vacuum sensing devices

6.4 The measurement of temperature 6.4.1 Thermoelectric sensors 6.4.2 Thermal radiation detection

6.5 The measurement of level 6.5.1 Simple float systems 6.5.2 Techniques using hydrostatic head 6.5.3 Capacitive sensing elements 6.5.4 6.5.5 The measurement of density (specific gravity) 6.6. I Liquids 6.6.2 Gases

6.7 The measurement of viscosity 6.7. I Off-line measurement of viscosity 6.7.2 Continuous on-line measurement of viscosity

6.8 The measurement of composition 6.8.1 Photometric analysers 6.8.2 Electrometric analysers 6.8.3 6.8.4 The mass spectrometer 6.8.5

Electric transducers for pressure measurement

Radioactive methods (nucleonic level sensing) Other methods of level measurement

6.6

The chromatograph as an on-line process analyser

Thermal conductivity sensors for gases

41 8 419 42 1 42 5 43 1 43 1 43 3

437 437 438 438 439 445 448 448 449 452 452 454 454 463 465 466 468 473 478 479 480 48 1 482 484 484 484 488 489 489 493 495 497 503 51 1 515 516

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6.8.6 The detection of water 519 6.8.7 Other methods of gas composition measurement 523

6.9 Process sampling systems 523 6.9.1 The sampling of single-phase systems 523 6.9.2 The sampling of multiphase systems (isokinetic sampling) 528

528 6.10.1 Definitions 528

535 6.11 . I Bridge circuits 536 6.1 1.2 Amplifiers 536 6.11.3 Signals and noise 537 6. 11.4 Filters 539 6. 11.5 Converters 539 6.1 1.6 Loading effects 542

6.12 Signal transmission (telemetry) 546

6.10 The static characteristics of sensors

6. I 1 Signal conditioning

6.12. I Multiplexers (time division multiplexing) 547 6.12.2 Serial digital signals 547 6.12.3 The transmission of analog signals 549 6.12.4 Non-electrical signal transmission 549

552 6.13 Further reading 552 6.14 References 553 6.15 Nomenclature 555

6.12.5 Smart transmitters and associated protocols-intelligent hardware

7. Process Control 7. I Introduction 7.2 Feedback control

7.2.1 The block diagram 7.2.2 Fixed parameter feedback control action 7.2.3 Characteristics of different control modes-offset

7.3 Qualitative approaches to simple feedback control system design 7.3.1 The heuristic approach 7.3.2

7.4.1 7.4.2 Block diagram algebra 7.4.3 Transfer functions of capacity systems 7.5.1 Order of a system 7.5.2 First-order systems 7.5.3 First-order systems in series 7.5.4 Second-order systems

7.6 Distance-velocity lag (dead time) 7.7 Transfer functions of fixed parameter controllers

7.7.1 Ideal controllers 7.7.2 Industrial three term controllers Response of control loop components to forcing functions 7.8. I Common types of forcing function 7.8.2 Response to step function 7.8.3 Initial and final value theorems 7.8.4 Response to sinusoidal function 7.8.5 Response to pulse function 7.8.6 Response of more complex systems to forcing functions

7.9 Transfer functions of feedback control systems 7.9.1 Closed-loop transfer function between C and R

The degrees of freedom approach

Linear systems and the principle of superposition

The poles and zeros of a transfer function

7.4 The transfer function

7.5

7.8

560 560 560 562 564 566 570 57 1 573 575 576 577 579 579 579 579 583 589 592 593 593 594 594 594 597 600 600 603 605 608 608

CONTENTS

7.9.2 Closed-loop transfer function between C and V 7.9.3 Calculation of offset from the closed-loop transfer function 7.9.4 The equivalent unity feedback system

7.10.1 The characteristic equation 7.10.2 The Routh-Hurwitz criterion 7.10.3 Destablising a stable process with a feedback loop 7.10.4 The Bode stability criterion 7.10.5 The Nyquist stability criterion 7.10.6 The log modulus (Nichols) plot

7.1 1.1 Frequency response methods 7.1 1.2 Process reaction curve methods 7.1 I .3 Direct search methods

7.12.1 Dead time compensation 7.12.2 Series compensation

7.13 Cascade control 7.14 Feed-forward and ratio control

7.10 System stability and the characteristic equation

7.1 1 Common procedures for setting feedback controller parameters

7.12 System compensation

7.14.1 Feed-forward control 7.14.2 Ratio control

7.15 MIMO systems-interaction and decoupling 7.15.1 Interaction between control loops 7.15.2 Decouplers and their design 7.15.3 Estimating the degree of interaction between control loops

7.16.1 Linearisation using Taylor’s series 7.16.2 The describing function technique

7.17.1 Sampled data (discrete time) systems 7.17.2 Block diagram algebra for sampled data systems 7.17.3 Sampled data feedback control systems 7.17.4 Hold elements (filters) 7.17.5 The stability of sampled data systems 7.17.6 Discrete time (digital) fixed parameter feedback controllers 7.17.7 Tuning discrete time controllers 7.17.8 Response specification algorithms

7.18.1 Scheduled (programmed) adaptive control 7.18.2 Model reference adaptive control (MRAC) 7.18.3 The self-tuning regulator (STR)

7.19 Computer control of a simple plant-the operator interface 7.19.1 Direct digital control (DDC) and supervisory control 7.19.2 Real time computer control 7.19.3 System interrupts 7.19.4 The operator/controller interface

7.20 Distributed computer control systems (DCCS) 7.20.1 Hierarchical systems 7.20.2 Design of distributed computer control systems 7.20.3 DCCS hierarchy 7.20.4 Data highway (DH) configurations 7.20.5 The DCCS operator station 7.20.6 System integrity and security 7.20.7 SCADA (Supervisory control and data acquisition)

7.2 1 The programmable controller 7.21.1 Programmable controller design 7.21.2 Programming the PLC

7.16 Non-linear systems

7.17 Discrete time control systems

7.18 Adaptive control

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609 609 61 1 612 61 3 614 617 619 625 632 632 634 635 638 638 638 640 645 646 646 65 1 653 653 654 658 660 66 1 664 672 672 675 677 679 68 1 684 686 686 688 689 690 69 1 692 692 694 696 696 698 698 698 700 703 703 708 708 709 709 71 1

xii CONTENTS

7.22 Regulators and actuators (controllers and control valves) 7.22.1 Electronic controllers 7.22.2 Pneumatic controllers 7.22.3 The control valve 7.22.4 Intelligent control valves

Appendix 7.1 Table of Laplace and z-transforms Appendix 7.2 Determination of the step response of a second-order system

7.23 Appendices

from its transfer function 7.24 Further reading 7.25 References 7.26 Nomenclature

Problems

Conversion Factors for Some Common SI Units

Index

712 712 715 719 724 726 726

726 729 729 73 1

737

750

753