HANDBOOK SECOND EDITION. Edited by

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1 HANDBOOK SECOND EDITION Edited by Martyn V. Twigg BSc, PhD, CChem., FRSC Catalytic Systems Division Johnson Matthey Plc. Formerly at the Catalysis Centre ICI Chemicals & Polymers Ltd MANSON PUBLISHING

Preface 16 Chapter 1. Fundamental Principles M.S. Spencer 1.1. Fundamentals of Heterogeneous Catalysis 17 1.1.1. Introduction 17 1.1.2. The Roleof Catalysis 18 1.1.2.1. Ammonia Synthesis 18 1.1.2.2. Ammonia Oxidation 19 1.

2 Preface 16 Chapter 1. Fundamental Principles M.S. Spencer 1.1. Fundamentals of Heterogeneous Catalysis Introduction The Roleof Catalysis Ammonia Synthesis Ammonia Oxidation The Nature of the Catalytic Process Catalyst Activity Catalyst Selectivity Steps in the Catalytic Process Adsorption and Desorption Catalyst Design Catalyst Manufacture Introduction Unsupported Metals Fused Catalysts Wet Methods of Catalyst Manufacture Fundamentals of Precipitation Processes Catalyst Manufacture by Precipitation Processes Impregnation Processes Forming Stages Catalyst Testing Introduction Chemical and Physical Properties Bulk Chemical Properties Surface Chemical Properties Physical Properties Catalyst Performance Coarse Laboratory Screening Fine Laboratory Screening Semi-technical Catalyst Testing Reaction Kinetics Catalyst Ageing Mechanism of the Catalytic Reaction 66

1.3.12.1. Ammonia Synthesis 67 1.3.12.2. Methanol Synthesis 68 1.4. Catalyst in Use 69 1.4.1. Introduction 69 1.4.2. Pretreatment and Activation 69 1.4.3. Loss of Catalyst Performance 73 1.4.4. Physical Causes of Decay 76 1.

3 Ammonia Synthesis Methanol Synthesis Catalyst in Use Introduction Pretreatment and Activation Loss of Catalyst Performance Physical Causes of Decay Poisoning by Impurities in Feeds or Catalysts Poisoning by Reactants or Products Interactions in Catalyst Deactivation 82 Chapter2. Process Design, Rating and Performance W.J. Lywood 2.1. Design of Catalytic Reactors Operating Temperature and Pressure Desulphurization Reactor Steam Reformers Water-gas Shift Reactors Methanation Reactor Ammonia and Methanol Synthesis Reactors Converter Types Single Adiabatic Bed Quench Converter Inter-bed Cooling ICI High-conversion Reactor Tube-cooled Reactor Steam-raising Reactor Catalyst Life Optimum Catalyst Size and Shape Voidage Catalyst Particle Size Design Conversion of Reactor Calculation of Catalyst Volume Catalyst Volume for Low concentration Reactant Being Removed Catalyst Volume for Low concentration Product Being Formed Equilibrium Concentrations Rate Constants Vessel Dimensions Reactor Rating 121

2.2.1. Optimum Operating Temperature 121 2.3. Catalyst Performance 123 2.3.1. Fall in Apparent Catalyst Activity 123 2.3.1.1. Poisoning/Sintering 123 2.3.1.2. Poor Gas Distribution 124 2.3.1.3. Poor Mixing of Reactants 124 2.

4 Optimum Operating Temperature Catalyst Performance Fall in Apparent Catalyst Activity Poisoning/Sintering Poor Gas Distribution Poor Mixing of Reactants Increase in Pressure Drop Breakage or Erosion of Catalyst Particles Disintegration of Catalyst Particles Deformation of Catalyst Particles Carry-over onto Catalyst Bed Collapse of Bed Support Measurement of Performance Analysis Mass Balance Catalyst-bed Temperature Rises Catalyst-bed Temperature Profiles Radioactive Tracing Pressure Drop Quantifying Catalyst Performance Composition at the Exit from the Reactor Approach to Equilibrium Activity or Active Volume of Catalyst Calculation of Catalyst Performance Reactor Exit Composition Calculation of Approach to Equilibrium Calculation of Activity or Active Volume from Composition Calculation of Activity or Active Volume from Temperature Profiles Application of Methods to Ammonia and Methanol Catalysts Desulphurizer Primary and Secondary Reformer High Temperature Shift Low Temperature Shift Methanator Ammonia and Methanol Synthesis Converter Computer Programs Reasons for Using Computer Calculations Accurate Calculations Non-isothermal Reactors Multiple Reactions Optimization Simulation Types of Computer Programs 138

Chapter3. Handling and Using Catalysts in the Plant D.R. Goodman 3.1. Introduction 140 3.2. Catalyst Storage 140 3.3. Drum Handling 141 3.4. Intermediate Bulk Containers and Socks 142 3.5.

5 Chapter3. Handling and Using Catalysts in the Plant D.R. Goodman 3.1. Introduction Catalyst Storage Drum Handling Intermediate Bulk Containers and Socks Sieving Catalyst Catalyst Charging Pre-charging Checks Charging Vessels Charging Ammonia Converters Charging Reformer Tubes Catalyst Reduction Reduction of Reforming Catalyst Typical Reduction with Steam and Natural Gas Reduction with Gas Recirculation Reduction of High-temperature Shift Catalyst Typical Reduction of High-temperature Shift Catalyst Reduction of Low-temperature Shift Catalyst Typical Reduction of Low-temperature Shift Catalyst Reduction of Methanation Catalyst Reduction of Ammonia Synthesis Catalyst Typical Reduction of a Tube-cooled Ammonia Converter Typical Reduction of a Multibed Quench Converter Catalyst Shutdown and Restarts Catalyst Regeneration Regeneration of Reforming Catalyst Regeneration of High-temperature Shift Catalyst Regeneration of Low-temperature Shift Catalyst Washing of Methanation Catalyst Regeneration of Ammonia Synthesis Catalyst Blanketing of Reduced Catalyst Catalyst Stabilization Stabilization of Reforming Catalyst Stabilization of High-temperature Shift Catalyst 180

3.11.3. Stabilization of Low-temperature Shift Catalyst 181 3.11.4. Stabilization of Methanation Catalyst 182 3.11.5. Stabilization of Ammonia Synthesis Catalyst 183 3.12. Catalyst Discharge 183 3.12.1. General 183 3.

6 Stabilization of Low-temperature Shift Catalyst Stabilization of Methanation Catalyst Stabilization of Ammonia Synthesis Catalyst Catalyst Discharge General Discharge of Pyrophoric Catalyst Top Discharge Blanketing Pyrophoric Catalyst During Vacuum Extraction Discharge of Ammonia Synthesis Catalyst Re-use of Discharged Catalyst Disposal of Used Catalyst Safety Precautions 188 Chapter 4. Feedstock Purification P.J.H. Carnell 4.1. Introduction Feedstocks for Ammonia, Methanol and Hydrogen Production Natural Gas Associated Gas, Natural Gas Condensates and LPG Naphtha Refinery Off Gases and Electrolytic Hydrogen Coal Gasification and Coke Oven Gas Mixed Feeds Desulphurization Processes for Single-stage Sulphur Removal Processes fortwo-stage Sulphur Removal Thermal Dissociation of Sulphur Compounds Hydrogenolysis of Sulphur Compounds Carbonyl Sulphide Cobalt Molybdate Catalysts Presulphiding Cobalt Molybdate Catalyst Other Reactions Over Cobalt Molybdate Catalyst Nickel Molybdate Catalysts Physical Form of Cobalt and Nickel Molybdate Catalysts Replacement and Discharging of Cobalt and Nickel Molybdate Catalysts 208

4.11. Zinc Oxide 209 4.11.1. Background to Zinc Oxide Absorbents 209 4.11.2. Thermodynamics and Reaction Kinetics 209 4.11.3. Formulation of Commercial Zinc Oxide 211 4.11.4. Use of Test Reactors to Assess Zinc Oxide Absorbents 211 4.

7 4.11. Zinc Oxide Background to Zinc Oxide Absorbents Thermodynamics and Reaction Kinetics Formulation of Commercial Zinc Oxide Use of Test Reactors to Assess Zinc Oxide Absorbents Effect of Temperature, Pressure and Space Velocity on Efficiency of Zinc Oxide Absorbents Effect of Gas Composition Effect ofreactor Design Other Desulphurization Uses for Zinc Oxide Impurities in Zinc Oxide Dechlorination Chloride Sources and Absorbents Operating Conditions Removal of Silica and Fluoride Demetallization Denitrification 224 Chapter 5. Steam Reforming D.E. Ridler, M.V. Twigg 5.1. History Feedstock and Feedstock Pretreatment Natural Gas Naphthas Chemistry of Steam Reforming Thermodynamics Kinetics Design of Steam Reforming Catalysts Selectivity Thermal Stability Physical Properties Nickel as a Steam Reforming Catalyst Supports for Nickel Steam Reforming Catalysts Carbon Formation on Reforming Catalysts Secondary Reforming Catalyst Dimensions Uses of Catalytic Steam Reforming 256

5.7.1. Ammonia Synthesis 256 5.7.2. Methanol Synthesis 258 5.7.3. Oxo Synthesis Gas 259 5.7.4. Reducing Gas 260 5.7.5. Town Gas 261 5.7.6. Substitute Natural Gas (SNG) 263 5.8. Practical Aspects of Steam Reformers 264 5.

8 Ammonia Synthesis Methanol Synthesis Oxo Synthesis Gas Reducing Gas Town Gas Substitute Natural Gas (SNG) Practical Aspects of Steam Reformers Containing the Catalyst Reactant Gas Distribution Firing the Reformer Expansion and Contraction of Reformer Tubes Facilities to Charge and Discharge Catalyst Designing a Reformer for Efficient Operation Catalyst Reduction Reduction with Hydrogen Reduction with Ammonia Reduction with Methanol Reduction with Natural Gas Reduction with Other Hydrocarbons Reduction After Shutdown Factors Affecting the Life of Reforming Catalyst Catalyst Poisons Sulphur Arsenic Hot Bands in Natural Gas Reformers 280 Chapter 6. The Water-gas Shift Reaction L. Lloyd, D.E. Ridler, M.V. Twigg 6.1. Introduction Thermodynamics Kinetics and Mechanism Kinetics Over HT Shift Catalyst Kinetics Over LT Shift Catalyst Mechanism of the Catalytic Water-gas Shift Reaction Converter Design High-temperature Shift High-temperature Shift Catalyst Formulation Diffusion Effects and Pellet Si'ze 295

6.5.2.1. Effect of Pellet Size on Activity 295 6.5.2.2. Effect of Pellet Sizeon Pressure Drop 296 6.5.3. Reduction of HT Shift Catalyst 298 6.5.4. Operation of HT Shift Catalyst 302 6.5.5. Poisoningand Deactivation 304 6.

9 Effect of Pellet Size on Activity Effect of Pellet Sizeon Pressure Drop Reduction of HT Shift Catalyst Operation of HT Shift Catalyst Poisoningand Deactivation Reoxidation and Discharge Low-temperature Shift General Low Temperature Shift Catalyst formulation Diffusion Effects and Pellet Size Reduction of LT Shift Catalyst General Considerations Once-through Reductions Recycle Reduction Systems Commissioning Reduced Catalyst Operation and Monitoring Performance Deactivation and Poisoning Deactivation Sulphur Poisoning Chloride and Other Poisons Oxidation and Discharge GuardBeds Economics of Operation Recent Developments Sulphur-tolerant Shift Catalysts Operation at Very Low Steam Ratios 338 Chapter 7. Methanation B.B. Pearce, M.V. Twigg, C. Woodward 7.1.Introduction Methanation in Ammonia and Hydrogen Plants Methanation Equlibria Kinetics and Mechanisms Catalyst Formulation Physical Properties of Methanation Catalysts Catalyst Reduction Catalyst Poisons Predictionof Catalyst Life Operating Experience Metiianation in Hydrogen Streams for Olefin Plants 367

7.4. Substitute Natural Gas (SNG) 368 7.4.1. Oil-based Routes to SNG 368 7.4.2. Coal-based Routes to SNG 372 7.4.2.1. Lurgi Coal/SNG Process 373 7.4.2.2. HICOM Coal/SNG Process 374 7.4.2.3. Other Developments 376 7.

10 7.4. Substitute Natural Gas (SNG) Oil-based Routes to SNG Coal-based Routes to SNG Lurgi Coal/SNG Process HICOM Coal/SNG Process Other Developments Heat Transfer Applications The EVA-ADAM Project 378 Chapter 8. Ammonia Synthesis J.R. Jennings, S.A. Ward 8.1. Introduction Thermodynamics of Ammonia Synthesis Theoretical Aspects Process Consequences The Synthesis Loop Ammonia Synthesis Catalysts The Iron Component Promoters Structural Promoters Electronic Promoters Catalyst Reduction Typical Plant Procedure Prereduced Catalysts Economics of Prereduced Catalyst Poisoning and Deactivation Introduction Temporary Poisoning in Ammonia Converters Permanent Poisoning in Ammonia Converters Kinetics and Mechanism Temkin Kinetics Effect of Catalyst Size Implications on Process Design Reaction Mechanism Plant Operation General Considerations Circulation Hydrogen/Nitrogen Ratio Influence of Inert Gas Concentration and Purge Rate 420

8.8. Commercial Ammonia Converters 423 8.8.1. General Considerations 8.8.1.1. Flow Type 423 424 8.8.1.2. Temperature Control and Heat Recovery 425 8.8.2. Quench Converter 8.8.3. Indirectly Cooled Multi-bed Converter 426 433 8.

11 8.8. Commercial Ammonia Converters General Considerations Flow Type Temperature Control and Heat Recovery Quench Converter Indirectly Cooled Multi-bed Converter Tube-cooled Converter The Future 439 Chapter 9. Methanol Synthesis G.W. Bridger, M.S. Spencer 9.1.Introduction Thermodynamic Aspects Methanol Formation Selectivity The Methanol Synthesis Process The Synthesis Loop Make-up Gas Composition Methanol Synthesis Catalysts High-pressure Catalysts Low-pressure Catalysts Selectivity and Poisons Mechanisms and Kinetics Reaction Mechanism Kinetics Recent Developments 467 Chapter 10. Catalytic Oxidations P. Davies, R.T. Donald, N.H. Harbord Introduction 469

10.2. Ammonia Oxidation 470 10.2.1. History of Nitric Acid Production 470 10.2.1.1. Routes from Atmospheric Nitrogen 470 10.2.1.2. Ammonia Oxidation 471 10.2.2. Chemistry of the Modern Process 477 10.

12 10.2. Ammonia Oxidation History of Nitric Acid Production Routes from Atmospheric Nitrogen Ammonia Oxidation Chemistry of the Modern Process The Chemistry of Absorption Nitric Oxide Oxidation Chemistry Ammonia Oxidation Chemistry Modern Plants The Burner Gauze Platinum/Rhodium Catalyst Gauze Activation Gauze Deactivation and Cleaning Metal Recovery Methanol Oxidation Introduction The Silver-catalysed Process Silver-catalysed Reactions Selectivity Poisoning Composition of Reaction Gases The Metal Oxide-catalysed Process Metal Oxide-catalysed Reactions Composition of Reaction Gases Future Process Developments Sulphur Dioxide Oxidation Introduction Thermodynamics Equilibrium Calculations Application to the Contact Process The Contact Process Vanadium Catalysts The Modern Sulphuric Acid Plant Mechanisms and Kinetics Catalyst Poisoning Disposal of Used Vanadium Catalysts Possible Further Developments 517 Appendices 1. Further Reading Numerical Examplesof the Use of Equations Derived in Chapter ICI Catalysts for the Production of Hydrogen, Ammonia and Methanol Pigtail Nipping ICI Technical Publications Equilibrium Constants: for the Methane-Steam Reaction at Various Temperatures Equilibrium Constants: for the CO Conversion Reaction (Shift) at Various Temperatures 543

8. Nomograph of Selected Properties of Ammonia 549 9. Thermodynamic Properties of Elements and Compounds at 298.15K 550 10. Physical Properties of Methanol 553 11.

13 8. Nomograph of Selected Properties of Ammonia Thermodynamic Properties of Elements and Compounds at K Physical Properties of Methanol Approximate Boiling Ranges of Hydrocarbon Feedstocks Monitoring Steam Reformer Tube Wall Temperature Heat Released During Catalyst Reduction Heat Released During Catalyst Oxidation Temperature Conversions Specific Heats of Catalysts Atomic Weights of the Common Elements Measurement of Pressure Drop Across Steam Reformer Tubes Charging Primary Steam Reformer Catalyst a Case Study Equilibrium Constants for the Reaction for Zinc Oxide with Hydrogen Sulphide Temperature Measurements in Catalyst Bed 574 References 576 Index 591 *

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