Synthetic Natural Gas

Tilman J. Schildhauer is a Senior Scientist at Paul Scherrer Institut, Switzerland since 2005, working mainly in the field of converting dry biomass to Synthetic Natural Gas (SNG) and electricity. These activities aim at developing sustainable and (energetically and economically) efficient processes based on the analysis of the complete process chain on the one hand and investigation of the fundamentals of the crucial process steps on the other hand. Since 2014, he is also Scientific Coordinator of the Energy Systems Integration platform at Paul Scherrer Institut. Dr. Schildhauer has authored over 60 scientific papers and two book chapters. Serge Biollaz is the Head of the Thermal Process Engineering group at Paul Scherrer Institut since 2000. In 2006/2007 he spent a sabbatical leave at Gas Technology Institute (GTI), Chicago, USA, working on catalytic biomass gasification, hot gas cleaning and integration of biomass/coal gasification with high temperature fuel cells (SOFC). Serge Biollaz co-authored more than 50 scientific papers and is national expert in the IEA Bioenergy, Task 33 Thermal gasification of biomass (since 2003), as well as expert on SNG in the European Biofuels Technology Platform (EBTP), WG2 "Conversion" (since 2009).

List of Contributors xi 1 Introductory Remarks 1 Tilman J. Schildhauer 1.1 Why Produce Synthetic Natural Gas? 1 1.2 Overview 3 2 Coal and Biomass Gasification for SNG Production 5 Stefan Heyne, Martin Seemann, and Tilman J. Schildhauer 2.1 Introduction Basic Requirements for Gasification in the Framework of SNG Production 5 2.2 Thermodynamics of Gasification 6 2.2.1 Gasification Reactions 7 2.2.2 Overall Gasification Process Equilibrium Based Considerations 7 2.2.3 Gasification A Multi]step Process Deviating from Equilibrium 11 2.2.4 Heat Management of the Gasification Process 13 2.2.5 Implication of Thermodynamic Considerations for Technology Choice 18 2.3 Gasification Technologies 18 2.3.1 Entrained Flow 19 2.3.2 Fixed Bed 20 2.3.3 Direct Fluidized Bed 22 2.3.4 Indirect Fluidized Bed Gasification 27 2.3.5 Hydrogasification and Catalytic Gasification 34 References 37 3 Gas Cleaning 41 Urs Rhyner 3.1 Introduction 41 3.2 Impurities 42 3.2.1 Particulate Matter 42 3.2.2 Tars 43 3.2.3 Sulfur Compounds 43 3.2.4 Halide Compounds 44 3.2.5 Alkali Compounds 44 3.2.6 Nitrogen Compounds 44 3.2.7 Other Impurities 44 3.3 Cold, Warm and Hot Gas Cleaning 45 3.3.1 Example of B]IGFC Gas Cleaning Process Chains 45 3.4 Gas Cleaning Technologies 47 3.4.1 Particulate Matter 47 3.4.2 Tars 52 3.4.3 Sulfur Compounds 57 3.4.4 Hydrodesulfurization 59 3.4.5 Chlorine (Halides) 60 3.4.6 Alkali 61 3.4.7 Nitrogen]containing Compounds 61 3.4.8 Other Impurities 62 3.5 Reactive Hot Gas Filter 62 References 65 4 Methanation for Synthetic Natural Gas Production Chemical Reaction Engineering Aspects 77 Tilman J. Schildhauer 4.1 Methanation The Synthesis Step in the Production of Synthetic Natural Gas 77 4.1.1 Feed Gas Mixtures for Methanation Reactors 79 4.1.2 Thermodynamic Equilibrium 82 4.1.3 Methanation Catalysts: Kinetics and Reaction Mechanisms 88 4.1.4 Catalyst Deactivation 97 4.2 Methanation Reactor Types 107 4.2.1 Adiabatic Fixed Bed Reactors 109 4.2.2 Cooled Reactors 117 4.2.3 Comparison of Methanation Reactor Concepts 129 4.3 Modeling and Simulation of Methanation Reactors 132 4.3.1 How to Measure (Intrinsic) Kinetics? 133 4.3.2 Modeling of Fixed Bed Reactors 136 4.3.3 Modeling of Isothermal Fluidized Bed Reactors 139 4.4 Conclusions and Open Research Questions 146 4.5 Symbol List 148 References 149 5 SNG Upgrading 161 Renato Baciocchi, Giulia Costa, and Lidia Lombardi 5.1 Introduction 161 5.2 Separation Processes for SNG Upgrading 163 5.2.1 Bulk CO2/CH4 Separation 163 5.2.2 Removal of other Compounds and Impurities 169 5.3 Techno]Economical Comparison of Selected Separation Options 174 References 176 6 SNG from Wood The GoBiGas Project 181 Jrgen Held 6.1 Biomethane in Sweden 181 6.2 Conditions and Background for the GoBiGas Project in Gothenburg 184 6.3 Technical Description 185 6.4 Technical Issues and Lessons Learned 188 6.5 Status 188 6.6 Efficiency 188 6.7 Economics 188 6.8 Outlook 189 Acknowledgements 189 References 189 7 The Power to Gas Process: Storage of Renewable Energy in the Natural Gas Grid via Fixed Bed Methanation of CO2/H2 191 Michael Specht, Jochen Brellochs, Volkmar Frick, Bernd Strmer, and Ulrich Zuberbhler 7.1 Motivation 191 7.1.1 History Renewable Fuel Paths at ZSW 191 7.1.2 Goal Energiewende 192 7.1.3 Goal Power Based, Carbon Based Fuels 192 7.1.4 Goal P2G 192 7.1.5 Goal Methanation 193 7.2 The Power to Fuel Concept: Co]utilization of (Biogenic) Carbon and Hydrogen 193 7.3 P2G Technology 196 7.3.1 Methanation Characteristics for CO2 Based Syngas 197 7.3.2 P2G Plant Layout of 25 kWel, 250 kWel, and 6000 kWel Plants 202 7.4 Experimental Results 206 7.4.1 Methanation Catalysts: Screening, Cycle