Concepts in Syngas Manufacture

Transcription

1 CATALYTIC SCIENCE SERIES VOL. 10 Series Editor: Graham J. Hutchings Concepts in Syngas Manufacture Jens Rostrup-Nielsen Lars J. Christiansen Haldor Topsoe A/S, Denmark Imperial College Press

2 Contents Preface Part I Basic Principles 1 Routes to Syngas General trends Towards focus and sustainability Direct or indirect conversion Manufacture by steam reforming of hydrocarbons Reactions and thermodynamics Product gas composition Thermodynamics of higher hydrocarbons The tubular reformer Carbon formation. Higher hydrocarbons Non-tubular reforming Other manufacture routes Partial oxidation Autothermal reforming Catalytic partial oxidation Air-blown technologies and membranes Choice of technology Other feedstocks Alcohols, oxygenates Coal, gasification Biomass Gas treatment Purification Water gas shift Acid gas removal 70 2 Syngas Applications Thermodynamic framework for syngas processes Syngas properties Synthesis process properties Process analysis Hydrogen Routes to hydrogen Hydrogen by steam reforming of hydrocarbons 87 vii

3 viii Concepts in Syngas Manufacture The steam export problem Membrane reforming Hydrogen via catalytic partial oxidation (CPO) Fuel cells Fuel processing system Internal reforming Process schemes for SOFC CO rich gases Town gas Oxogas Reducing gas Ammonia Methanol and synfuels Methanol as intermediate Methanol plant Methanol via gasification Combined syntheses and co-production Fischer Tropsch synthesis SNG Chemical recuperation 138 Part II Steam Reforming Technology 3 Technology of Steam Reforming Early developments Steam reforming reactors Role of catalyst The tubular reformer Scale-up of steam reforming technology Plant measurements Reformer temperature measurements Modelling of steam reforming reactors Two-dimensional reactor model Heat transfer in the two-dimensional model Heat transfer parameters in syngas units Pressure drop Convective reformers Tubular reformer furnace chamber Tubular reforming limits of Operation Micro-scale steam reforming reactors Modelling of the catalyst particle Catalyst particle model Effective diffusion coefficients 195

4 Contents ix Simulation of a hydrogen plant reformer Reaction kinetics Industrial rates and the scale-down problem Intrinsic kinetics. Steam reforming of methane Steam reforming of higher hydrocarbons CO2 reforming Catalyst Properties and Activity Catalyst structure and stability Reactions with the support Activation and nickel surface area Nickel surface area Measurement of nickel surface area Nickel surface area and catalyst preparation Sintering Catalyst activity Group VIII metals Non-metal catalysts Thermal reactions catalytic steam cracking Carbon and Sulphur Secondary phenomena Carbon formation Routes to carbon Carbon from reversible reactions Principle of equilibrated gas Principle of actual gas and steady-state equilibrium Steam reforming of higher hydrocarbons Whisker carbon in tubular reformer Catalyst promotion "Gum formation" in prereformers Carbon from pyrolysis Regeneration of coked catalyst Sulphur poisoning of reforming reactions Chemisorption of hydrogen sulphide Chemisorption equilibrium Dynamics of sulphur poisoning Regeneration for sulphur Impact of sulphur an reforming reactions Sulphur passivated reforming Other poisons Catalysis of Steam Reforming Historical perspective The role of step sites 298

5 x Concepts in Syngas Manufacture 6.3 Geometric or electronic effects Metal activity. Micro-kinetics The parallel approach 311 Appendix 1 Enthalpy of formation 313 Appendix 2 Chemical equilibrium constants 317 Notation and Abbreviation 323 References 331 Author index 357 Subject index 369