Technologies for Converting Biomass to Useful Energy: Combustion, Gasification, Pyrolysis, Torrefaction and Fermentation

Officially, the use of biomass for energy meets only 10-13% of the total global energy demand of 140 000 TWh per year. Still, thirty years ago the official figure was zero, as only traded biomass was included. While the actual production of biomass is in the range of 270 000 TWh per year, most of this is not used for energy purposes, and mostly it is not used very efficiently. Therefore, there is a need for new methods for converting biomass into refined products like chemicals, fuels, wood and paper products, heat, cooling and electric power. Obviously, some biomass is also used as food – our primary life necessity. The different types of conversion methods covered in this volume are biogas production, bio-ethanol production, torrefaction, pyrolysis, high temperature gasifi cation and combustion. This book covers the suitability of different methods for conversion of different types of biomass. Different versions of the conversion methods are presented – both existing methods and those being developed for the future. System optimization using modeling methods and simulation are analyzed to determine advantages and disadvantages of different solutions. Many international experts have contributed to provide an up-to-date view of the situation all over the world. These global perspectives and the inclusion of so much expertise of distinguished international researchers and professionals make this book unique. This book will prove useful and inspiring to professionals, engineers, researchers and students as well as to those working for different authorities and organizations.

Table of Contents:
1. An overview of thermal biomass conversion technologies Erik Dahlquist 2. Simulations of combustion and emissions characteristics of biomass-derived fuels Suresh K. Aggarwal 2.1 Introduction 2.2 Thermochemical conversion processes 2.2.1 Direct biomass combustion 2.2.2 Biomass pyrolysis 2.2.3 Biomass gasification 2.3 Syngas and biogas combustion and emissions 2.3.1 Syngas combustion and emissions 2.3.2 Non-premixed and partially premixed syngas flames 2.3.3 High pressure and turbulent syngas flames 2.3.4 Syngas combustion in practical devices 2.4 Biogas combustion and emissions 2.5 Concluding remarks 3. Energy conversion through combustion of biomass including animal waste Kalyan Annamalai, Siva Sankar Thanapal, Ben Lawrence,Wei Chen, Aubrey Spear & John Sweeten 3.1 Introduction 3.2 Overview on energy conversion from animal wastes 3.2.1 Manure source 3.3 Biological conversion 3.3.1 Digestion 3.3.2 Fermentation 3.4 Thermal energy conversion 3.5 Fuel properties 3.5.1 Proximate and ultimate analyses 3.5.2 Empirical formula for heat values 3.5.2.1 The higher heating value per unit mass of fuel 3.5.2.2 The higher heat value per unit stoichiometric oxygen 3.5.2.3 Heat value of volatile matter 3.5.2.4 Volatile matter and stoichiometry 3.5.2.5 Stoichiometric A:F 3.5.2.6 Flue gas volume 3.5.3 Fuel change and effect on CO2 3.5.4 Air flow rate and multi-fuels firing 3.5.5 CO2 and fuel substitution 3.6 TGA studies on pyrolysis and ignition 3.6.1 Pyrolysis 3.7 Model 3.7.1 Single reaction model: Conventional Arrhenius method 3.7.2 Parallel Reaction Model (PRM) 3.8 Chemical kinetics 3.8.1 Activation energy from single reaction model 3.8.2 Activation energies from parallel reaction model 3.9 Ignition 3.9.1 Ignition temperature 3.10 Cofiring 3.10.1 Experimental set up and procedure 3.10.2 Experimental parameters 3.10.3 O2 and equivalence ratio 3.10.4 CO and CO2 emissions 3.10.5 Burnt fraction 3.10.6 NOx emissions 3.10.7 Fuel nitrogen conversion efficiency 3.11 Cofiring FB with coal 3.11.1 NO emissions with longer reactor 3.11.2 Effect of blend ratio 3.12 Reburn 3.13 Low NOx Burners (LNB) 3.14 Gasification 3.14.1 Experimental setup 3.14.2 Experimentation 3.14.3 Experimental procedure 3.14.4 Results and discussion 3.14.4.1 Fuel properties 3.14.4.2 Experimental results and discussion 3.14.4.2.1 Temperature profiles for air gasification 3.14.4.2.2 Temperature profiles for enriched air gasification and CO2: O2 gasification 3.14.4.2.3 Gas composition results with air 3.14.4.2.4 Gas composition results with enriched air and CO2: O2 mixture 3.14.4.2.5 HHV of gases and energy conversion efficiency 3.15 Summary and conclusions 4. Co-combustion coal and bioenergy and biomass gasification: Chinese experiences Changqing Dong & Xiaoying Hu 4.1 Biomass resources in China 4.1.1 Agricultural residues 4.1.2 Livestock manure 4.1.3 Municipal and industrial waste 4.1.4 Wood processing remainders 4.2 Co-combustion in China 4.2.1 Introduction 4.2.2 Methods and technologies 4.2.3 Advantages and disadvantages 4.2.4 Research status 4.2.4.1 Different biomass for co-combustion 4.2.4.2 Biomass gasification gas for co-combustion 1 4.2.4.3 Pollutant emissions from co-combustion 4.2.4.3.1 The influence of solid biomass fuel 4.2.4.3.2 The influence of biomass gasification gas 4.2.5 The applications of co-combustion in China 4.2.5.1 Chuang Municipality Lutang Sugar Factory 4.2.5.2 Fengxian XinYuan Biomass CHP Thermo Power Co., Ltd 4.2.5.3 Heilongjiang Jiansanjiang Heating and Power Plant 4.2.5.4 Baoying Xiexin Biomass Power Co., Ltd 4.2.6 Shiliquan power plant 4.3 Biomass gasification in China 4.3.1 Introduction 4.3.2 Gasification technology development 4.3.3 Biomass gasification gas as boiler fuel 4.3.3.1 The feasibility of biomass gasification gas as fuel 4.3.3.2 The superiority of biomass gasification gas as fuel 4.3.4 Biomass gasification gas used for drying 4.3.5 Biomass gasification power generation 4.3.6 Biomass gasification for gas supply 4.3.7 Hydrogen production from biomass gasification 4.3.8 Biomass gasification polygeneration scheme 4.3.9 Policy-oriented biomass gasification in China 4.3.9.1 Guide public awareness 4.3.9.2 Government investment in R&D of key technologies 4.3.9.3 Fiscal incentives and market regulation measures 4.4 Conclusions 4.4.1 Co-combustion 4.4.2 Gasification 5. Biomass combustion and chemical looping for carbon capture and storage Umberto Desideri & Francesco Fantozzi 5.1 Feedstock properties 5.1.1 Biomass and biofuels definition and classification 5.1.2 Biomass composition and analysis 5.1.3 Biomass analysis 5.1.3.1 Moisture content (EN 14774-2, 2009) 5.1.3.2 Ash content (EN 14775, 2009) 5.1.3.3 Volatile matter (EN 15148, 2009) 5.1.3.4 Heating value (EN 14918, 2009) 5.1.3.5 Carbon, hydrogen and nitrogen content (EN 15104, 2011) 5.1.3.6 Density (EN 15103, 2010) 5.1.3.7 Sulfur content analysis (EN 15289, 2011) 5.1.3.8 Chlorine and fluorine content analysis (EN 15289, 2011) 5.1.3.9 Chemical analysis (EN 15297, 2011 and EN 15290, 2011) 5.1.3.10 Size (CEN/TS 15149-1:2006, CEN/TS 15149-2:2006, CEN/TS 15149-3:2006) 5.2 Combustion basics 5.2.1 Introduction 5.2.2 Heating and drying 5.2.3 Pyrolysis and devolatilization 5.2.4 Char oxidation (glowing or smoldering combustion) 5.2.5 Volatiles oxidation (flaming combustion) 5.2.6 Combustion rates, flame temperature and efficiency 5.3 Combustors 5.3.1 Introduction to biomass combustion systems 5.3.2 Fixed bed combustion 5.3.2.1 Pile burners 5.3.2.2 Grate burners 5.3.3 Moving bed combustors 5.3.3.1 Suspension burners 5.3.3.2 Fluidized bed combustors 5.3.4 Design and operation issues 5.3.4.1 Design principles 5.3.4.2 Deposit and slagging problems 5.4 Chemical looping combustion 5.4.1 Chemical looping processes 5.4.2 Chemical looping reactions 6. Biomass and black liquor gasification Klas Engvall, Truls Liliedahl & Erik Dahlquist 6.1 Introduction 6.2 Theory of gasification 6.3 Operating conditions of importance for the product composition 6.3.1 Fuel types and properties 6.3.1.1 Biomass 6.3.1.2 Black liquor 6.3.1.3 Biomass properties of importance for gasification 6.3.2 Gasifying agent 6.3.3 Temperature 6.4 Gasification systems 6.4.1 Gasification technologies 6.4.1.1 Fixed bed 6.4.1.1.1 Updraft gasifiers 6.4.1.1.2 Downdraft gasifers 6.4.1.1.3 Cross-draft gasifers 6.4.1.2 Fluidized bed gasifiers 6.4.1.2.1 BFB and CFB reactors 6.4.1.2.2 Dual fluidized bed reactors 6.4.1.3 Entrained flow gasifier 6.4.2 Gas cleaning and upgrading 6.4.2.1 Tar and tar removal 6.4.2.2 Thermal and catalytic tar decomposition 6.4.2.2.1 Thermal processes for tar destruction 6.4.2.2.2 Catalytic processes for tar destruction 6.4.2.2.3 Dolomite catalysts 6.4.2.2.4 Nickel catalysts 6.4.2.2.5 Alkali metal catalysts 6.4.2.3 Removal of other impurities found in the product gas 6.4.2.3.1 Alkali metal compounds 6.4.2.3.2 Fuel-bound nitrogen 6.4.2.3.3 Sulfur 6.4.2.3.4 Chlorine 6.5 Gasification applications 6.5.1 Biomass gasification 6.5.1.1 BFB gasifier at Skive 6.5.1.2 CortusWoodRoll gasification technology 6.5.1.2.1 Güssing plant 6.5.2 Black liquor gasification 6.5.2.1 BL gasification using fluidized bed technology 6.5.2.2 BL gasification using entrained flow technology 6.6 Modelling of gasification systems 6.6.1 Material and energy balance models 6.6.1.1 An empirical model for fluidized bed gasification 6.6.2 Kinetic models 6.6.3 Equilibrium models 6.6.3.1 Simulations using an equilibrium model compared to experimental data 6.7 Outlook 6.7.1 Biomass gasification 6.7.2 Black liquor gasification 7. Biomass conversion through torrefaction Anders Nordin, Linda Pommer, Martin Nordwaeger & Ingemar Olofsson 7.1 Introduction 7.2 Torrefaction history 7.2.1 Origin of torrefaction processes 7.2.2 Modern torrefaction work (1980–) 7.3 Torrefaction process 7.3.1 Energy and mass balances 7.3.2 Solid product characteristics 7.3.2.1 Elemental compositional changes 7.3.2.2 Heating value and volatile content 7.3.2.3 Friability, grinding energy and powder characteristics 7.3.2.4 Feeding characteristics 7.3.2.5 Hydrophobic properties and fungal durability 7.3.2.6 Molecular composition and changes 7.3.3 Gases produced 7.3.3.1 Permanent gases 7.3.3.2 Condensable gases 7.4 Subsequent refinement processes 7.4.1 Washing 7.4.2 Densification 7.4.2.1 Pelleting 7.4.2.2 Briquetting 7.5 Torrefaction technologies 7.5.1 General 7.5.2 Technologies under development or demonstration 7.5.3 Status of the present production plants erected 7.6 End-use experience 7.7 System analyses and process integration 7.7.1 Importance of total supply chain analysis 7.7.2 Process and system integration 7.8 Economic aspects of torrefaction systems 7.8.1 Investment and operating costs 7.8.2 Costs versus total supply chain savings 7.9 Outlook 8. Biomass pyrolysis for energy and fuels production Efthymios Kantarelis, Weihong Yang & Wlodzimierz Blasiak 8.1 Introduction 8.2 Technologies 8.2.1 Biomass reception and storage 8.2.2 Fast pyrolysis reactors 8.2.2.1 Bubbling fluidized beds 8.2.2.2 Circulating fluidized bed reactors 8.2.2.3 Rotating cone reactors 8.2.3 Char separation 8.2.4 Liquid recovery 8.3 Products and applications 8.3.1 Char 8.3.2 Bio-oil 8.3.2.1 Composition and properties 8.3.2.1.1 Homogeneity 8.3.2.1.2 Water content 8.3.2.1.3 Viscosity/rheological properties 8.3.2.1.4 Acidity 8.3.2.1.5 Heating value 8.3.2.1.6 Stability 8.3.2.1.7 Health and safety 8.3.2.1.8 Other important properties 8.3.2.2 Bio-oil applications 8.3.2.2.1 Heat and power 8.3.2.2.2 Gasoline and diesel fuels 8.4 Modeling 8.4.1 One step models 8.4.2 Models with competing parallel reactions 8.4.2.1 Models with secondary reactions 8.5 Recent trends and developments 8.6 Conclusions 9. Solid-state ethanol production from biomass Shi-Zhong Li 9.1 Introduction 9.1.1 The history of SSF 9.2 The principle of SSF 9.2.1 Microorganisms in SSF 9.2.2 The substrate in SSF 9.2.2.1 The source of the substrate 9.2.2.2 The character of the substrate 9.2.2.3 The water content of the substrate 9.2.2.4 The solid-phase properties of substance 9.3 The process of SSF 9.3.1 The characteristics of SSF 9.3.1.1 Cell growth and measurement of products 9.3.1.2 Sterile control 9.3.2 The effective factors of SSF 9.3.2.1 Carbon and nitrogen sources 9.3.2.2 Temperature and heat transfer 9.3.2.3 Moisture and water activity 9.3.2.4 Ventilation and mass transfer 9.3.2.5 pH value 9.3.3 SSF reactors 9.3.3.1 Static SSF reactor 9.3.3.2 Dynamic SSF reactor 9.3.3.3 Rotary drum SSF reactor and modeling progress 9.4 Progress of SSF research 9.5 Application of SSF in biomass energy fields 9.5.1 Sweet sorghum stalk liquid fermentation technology 9.5.2 Sweet sorghum stalk SSF technology 9.5.3 The prospect of SSF 9.5.3.1 Basic theory for research 9.5.3.2 SSF reactor design and scale-up 9.5.3.3 The SSF process and product contamination control 10. Optimization of biogas processes: European experiences Anna Behrendt, S. Drescher-Hartung & Thorsten Ahrens 10.1 Introduction 10.2 Substrates for biogas processes and specialities 10.2.1 Available substrate streams for biogas processes, composition and organic amounts 10.2.1.1 Water and organic matter concentration 10.2.1.2 Requirements for pretreatment including sorting and sanitation 10.2.2 Biogas potentials and energy output 10.2.2.1 Identification of biogas potentials 10.2.2.2 Biogas potential results and energy output 10.2.2.3 Comparison of energy outputs through biogas and combustion of material 10.2.3 Conclusion: Can energy from waste compete with energy from renewable products? 10.3 Current biogas technologies and challenges 10.3.1 Biogas fermenter technology 10.3.1.1 Dry digestion application – Examples of biogas plants in Germany 10.3.1.1.1 Plug flow fermenter 10.3.1.1.2 Tower fermenter 10.3.1.1.3 Garage fermenter 10.3.1.2 Wet digestion applications 10.3.1.2.1 System example 10.3.1.2.2 Use of residual waste 10.3.1.3 Laboratory scale technology 10.3.1.3.1 Plug flow fermenter 10.3.1.3.2 Garage fermenter 10.3.2 Regional implementation of fermenter technology 10.3.2.1 One European example: Conditions in Estonia (Kiili Vald) 10.3.2.2 The waste management situation in Kiili Vald 10.3.2.3 The waste management situation in Germany 10.4 Future prospects and individual regional energy solutions 10.4.1 Central and local biogas plants 10.4.1.1 Individual farm plant 10.4.1.2 Biogas parks 10.4.2 Biogas use 10.5 Questions for discussions 11. Biogas – sustainable energy solutions in Nigeria Adeola Ijeoma Eleri 11.1 Introduction 11.2 Review of Nigeria’s current energy situation 11.3 Biogas technology in Nigeria 11.3.1 Technical characteristics of biogas digester 11.3.2 Mechanisms of methanogenesis 11.4 Potentials of biogas technology for sustainable development 11.5 Barriers to biogas technology 11.6 Recommendations for scaling up biogas technology in Nigeria 11.7 Conclusions 12. The influence of biodegradability on the anaerobic conversion of biomass into bioenergy Rodrigo A. Labatut 12.1 Introduction 12.2 Theoretical aspects and assessment of substrate biodegradability 12.3 Factors limiting substrate biodegradability 12.3.1 Bioenergetics: Cell synthesis vs. metabolic energy 12.3.2 Polymer complexity 12.3.2.1 Carbohydrates 12.3.2.2 Proteins 12.3.2.3 Lipids 12.3.3 Inhibition of biochemical reactions 12.4 Biodegradability of complex, particulate influents: Co-digestion studies 12.4.1 The effect of substrate composition on fD and Bo: BMP studies 12.4.2 Implications of influent biodegradability on anaerobic digestion systems 12.5 Conclusions 13. Pellet and briquette production Torbjörn A. Lestander 13.1 Introduction 13.2 Standardization of solid biofuels 13.3 Feedstock for densification 13.3.1 Raw materials 13.3.2 Biomass has orthotropic mechanical properties 13.4 Pretreatment before densification 13.4.1 Grinding 13.4.2 Pre-heating (e.g. steam addition) 13.4.3 Steam explosion 13.4.4 Ammonia fiber expansion 13.4.5 Drying 13.4.6 Torrefaction 13.5 Densification techniques 13.6 Mechanisms of bonding 13.7 Health and safety aspects when handling pellets and briquettes 13.8 Conclusion 13.9 Questions for discussion 14. Dynamic modeling and simulation of power plants with biomass as a fuel Yrjö Majanne 14.1 Introduction 14.1.1 Use of biomass as an energy source 14.1.2 Modeling of biomass combustion 14.2 Simulation in power plant design and operation 14.2.1 Simulation tools 14.2.2 Simulator requirements 14.3 Biomass as a fuel 14.4 Biomass-fired power plants 14.4.1 Grate combustion 14.4.2 Fluidized bed combustion 14.4.2.1 Bubbling fluidized bed combustion 14.4.2.2 Circulating fluidized bed combustion 14.5 Modelling of biomass combustion 14.5.1 Thermodynamic properties 14.5.1.1 Thermal conductivity 14.5.1.2 Specific heat 14.5.1.3 Heat of formation 14.5.1.4 Heat of reaction 14.5.1.5 Ignition temperature 14.5.2 Combustion process 14.5.2.1 Drying and ignition 14.5.2.2 Pyrolysis and combustion of volatile components 14.5.2.3 Combustion of remaining charcoal 14.6 Conclusions 14.7 Questions for discussions 15. Optimal use of bioenergy by advanced modeling and control Bernt Lie & Erik Dahlquist 15.1 Current and future work in bioenergy system automation 15.2 Overview of processes 15.2.1 Biomass 15.2.2 Thermochemical processes 15.2.3 Biochemical processes 15.2.3.1 Fermentation 15.2.3.2 Anaerobic digestion 15.2.3.3 Biochemical processing 15.2.4 Characterization of processes 15.3 Process information 15.3.1 Sensors and instrumentation 15.3.2 Modeling and process description 15.3.2.1 Mechanistic models 15.3.2.2 Models and model error 15.3.2.3 Empirical models 15.3.2.4 Model building and model simulation 15.3.3 Monitoring and fault detection 15.4 Process operation 15.4.1 Control and maintenance 15.4.2 Management and integration into product grids 15.5 Diagnostics and control using on-line physical simulation models 15.5.1 Introduction 15.5.2 Approach description 15.5.3 Boiler 15.5.4 Other energy conversion processes 15.5.5 Model validation and results 15.5.6 Discussion 15.6 Conclusions and questions for discussion 16. Energy and exergy analyses of power generation systems using biomass and coal co-firing Marc A. Rosen, Bale V. Reddy & Shoaib Mehmood 16.1 Introduction 16.2 Background 16.2.1 Co-firing and its advantages 16.2.2 Global status of co-firing 16.2.3 Properties of biomass and coal 16.2.4 Technology options for co-firing 16.2.4.1 Direct co-firing 16.2.4.2 Parallel co-firing 16.2.4.3 Indirect co-firing 16.3 Relevant studies on co-firing 16.3.1 Co-firing studies 16.3.2 Experimental studies 16.3.3 Modeling and simulation studies 16.3.4 Energy and exergy analyses 16.3.5 Economic studies 16.4 Characterstics of biomass fuels and coals 16.5 Co-firing system configurations 16.6 Thermodynamic modeling, simulation and analysis of co-firing systems 16.6.1 Approach and methodology 16.6.2 Assumptions and data 16.6.3 Governing equations 16.6.3.1 Analysis of boiler 16.6.3.2 Analysis of high pressure turbine 16.6.3.3 Analysis of low pressure turbine 16.6.3.4 Analysis of condenser 16.6.3.5 Analysis of condensate pump 16.6.3.6 Analysis of boiler feed pump 16.6.3.7 Analysis of open feed water heater 16.6.4 Boiler and overall energy and exergy efficiencies 16.7 Effect of biomass co-firing on coal power generation systems 16.7.1 Effect of co-firing on overall system performance 16.7.2 Effect of co-firing on energy and exergy losses 16.7.2.1 Effect of co-firing on furnace exit gas temperature 16.7.2.2 Effect of co-firing on energy losses and external exergy losses 16.7.2.3 Effect of co-firing on irreversibilities 16.7.3 Effect of co-firing on efficiencies 16.7.3.1 Boiler energy efficiency 16.7.3.2 Plant energy efficiency 16.7.3.3 Boiler exergy efficiency 16.7.3.4 Plant exergy efficiency 16.7.4 Effect of co-firing on emissions 16.7.4.1 Energy-based CO2 emission factors 16.7.4.2 Energy-based NOx emission factors 16.7.4.3 Energy-based SOx emission factors 16.8 Conclusions 16.9 Questions for discussions 17. Control of bioconversion processes K.P. Madhavan & Sharad Bhartiya 17.1 Introduction 17.2 Process dynamics 17.2.1 Physico-chemical models 17.2.1.1 Single vessel continuous digester for wood pulping 17.2.1.2 A physico-chemical model for the pulp digester 17.3 Approximate models to capture essential dynamics 17.3.1 Single capacity element: first order system 17.3.2 Second order system 17.3.3 Dynamics of higher order processes 17.3.4 Pure time delay processes 17.3.5 Control relevant models for process control systems design 17.3.6 Linear system identification: single-vessel digester case study 17.3.7 Discrete-time models for sampled data system 17.3.8 Discrete-time models for nonlinear processes 17.4 Basic strategies for control 17.4.1 Single feedback loop control 17.4.2 Internal model control structure 17.4.3 PI control of lower heater Kappa and blowline Kappa number 17.4.4 Single-loop control with disturbance compensation 17.4.4.1 Input disturbances: cascade control 17.4.4.2 Output disturbances: feedforward–feedback control 17.4.5 Feedback control with time delay compensation: the Smith predictor 17.4.6 Single loop control with nonlinear compensation 17.5 Unit-wide or multivariable control 17.5.1 Decentralized approach 17.5.1.1 Measures of multivariable interaction: relative gain array (RGA) 17.5.1.2 Interaction analysis for the single vessel digester 17.6 Multiple single loop control using interaction compensators: Decoupler design 17.6.1 Decoupler design for single vessel digester 17.7 Model predictive control: A multivariable control strategy 17.7.1 Linear model predictive control for the single vessel digester 17.7.2 Control results and discussion 17.8 Real-time optimization 17.9 Concluding remarks 17.10 Questions for discussion Subject index