Efficiency of Biomass Energy

Preface xv Acknowledgments xix About the Author xxi PART I | Background and Outline Chapter 1 | Bioenergy Systems: An Overview 3 1.1 Energy and the Environment 3 1.2 Biomass as a Renewable Energy Source 13 1.3 Biomass Conversion Processes 22 1.4 Utilization of Biomass 27 1.5 Closing Remarks 34 References 34 Chapter 2 | Exergy Analysis 37 2.1 Sustainability and Efficiency 37 2.2 Thermodynamic Analysis of Processes 42 2.3 Exergy Concept 52 2.4 Exergetic Evaluation of Processes and Technologies 67 2.5 Renewability of Biofuels 81 2.6 Closing Remarks 86 References 86 PART II | Biomass Production and Conversion Chapter 3 | Photosynthesis 93 3.1 Photosynthesis: An Overview 93 3.2 Exergy of Thermal Radiation 99 3.3 Exergy Analysis of Photosynthesis 106 3.4 Global Photosynthesis 116 3.5 Closing Remarks 120 References 120 Chapter 4 | Biomass Production 123 4.1 Overview 123 4.2 Efficiency of Solar Energy Capture 133 4.3 Fossil Inputs for Biomass Cultivation and Harvesting 140 4.4 Fossil Inputs for Biomass Logistics 146 4.5 Closing Remarks 150 References 150 Chapter 5 | Thermochemical Conversion: Gasification 153 5.1 Gasification: An Overview 153 5.2 Gasification of Carbon 171 5.3 Gasification of Biomass 183 5.4 Gasification of Typical Fuels 191 5.5 Closing Remarks 198 References 198 Chapter 6 | Gasification: Parametric Studies and Gasification Systems 203 6.1 Effect of Fuel Chemical Composition on Gasification Performance 203 6.2 Effect of Biomass Moisture Content, Gasification Pressure, and Heat Addition on Gasification Performance 211 6.3 Improvement of Gasification Exergetic Efficiency 215 6.4 Gasification Efficiency Using Equilibrium versus Nonequilibrium Models 230 6.4.1 Quasi-Equilibrium Thermodynamic Models 231 6.4.2 Comparison of Gasification Efficiency 231 6.5 Performance of Typical Gasifiers 233 6.5.1 Comparison of FICFB and Viking Gasifiers 233 6.5.2 Fluidized-Bed Gasifiers for the Production of H2-Rich Syngas 238 6.5.3 Downdraft Fixed-Bed Gasifier 241 6.5.4 Updraft Fixed-Bed Gasifier 242 6.6 Plasma Gasification 244 6.6.1 Plasma Gasification Technology 244 6.6.2 Plasma Gasification of Sewage Sludge 244 6.7 Thermochemical Conversion in Sub- and Supercritical Water 246 6.7.1 Conversion of Wet Biomass in Hot Compressed Water 246 6.7.2 Supercritical Water Gasification (SCWG) 247 6.7.3 Hydrothermal Upgrading (HTU) under Subcritical Water Conditions 251 6.8 Closing Remarks 253 References 253 PART III | Biofuels First-Generation Biofuels Chapter 7 | Biodiesel 261 7.1 Biodiesel: An Overview 261 7.1.1 Introduction 261 7.1.2 Historical Development 262 7.1.3 Chemistry 263 7.1.4 Feedstocks 265 7.1.5 Production Process 266 7.1.6 Biodiesel as Transport Fuel 268 7.1.7 Energy, Environmental, and Economic Performance 269 7.2 Biodiesel from Plant Oils 272 7.2.1 Exergy Analysis of Transesterification 272 7.2.2 Exergy Analysis of Overall Production Chain 275 7.3 Biodiesel from Used Cooking Oil 278 7.3.1 Exergy Analysis of Biodiesel Production 278 7.3.2 Exergy Analysis of Overall Production Chain 281 7.4 Biodiesel from Microalgae 281 7.4.1 Introduction 281 7.4.2 Exergy Analysis of Transesterification of Algal Oil 282 7.4.3 Exergy Analysis of Overall Production Chain of Algal Biodiesel 284 7.5 Closing Remarks 286 References 286 Chapter 8 | Bioethanol 289 8.1 Bioethanol: An Overview 289 8.1.1 Introduction 289 8.1.2 Historical Development 290 8.1.3 Ethanol as Transport Fuel 291 8.1.4 Chemistry 293 8.1.5 Bioethanol Production Methods 295 8.1.6 Energy, Environmental and Economic Aspects 302 8.2 Exergy Analysis of Ethanol from Sugar Crops 305 8.2.1 Introduction 305 8.2.2 Ethanol from Sugarcane 306 8.2.3 Exergetic Performance of Sugarcane Ethanol Plants for Various Cogeneration Configurations 310 8.2.4 Ethanol from Sugar Beets 313 8.2.5 Renewability of Ethanol from Sugar Crops 315 8.3 Exergy Analysis of Ethanol from Starchy Crops 317 8.3.1 Introduction 317 8.3.2 Corn Ethanol: Exergy Analysis 317 8.3.3 Corn Ethanol: Cumulative Exergy Consumption (CExC) and Renewability 319 8.3.4 Wheat Ethanol 322 8.4 Exergy Analysis of Lignocellulosic Ethanol (Second Generation) 323 8.4.1 Introduction 323 8.4.2 Ethanol from Wood (NREL Process) 324 8.4.3 Impact of Biomass Pretreatment and Process Configuration 328 8.4.4 Comparison of Exergetic Efficiency 330 8.4.5 Renewability of Lignocellulosic Ethanol from Tropical Tree Plantations 331 8.5 Alternative Ethanol Processes 332 8.5.1 Fossil Ethanol from Mineral Oil 332 8.5.2 Ethanol via Water Electrolysis 333 8.6 Closing Remarks 334 References 334 Second-Generation Liquid Biofuels Chapter 9 | Fischer–Tropsch Fuels 341 9.1 Fischer–Tropsch Synthesis: An Overview 341 9.1.1 Introduction 341 9.1.2 Historical Development 342 9.1.3 Process Chemistry 343 9.1.4 Comparison of F-T Fuels to Conventional Transport Fuels 345 9.1.5 Process Design 346 9.1.6 Process Performance 348 9.2 Exergy Analysis of Coal-to-Liquid (CTL) Process 351 9.2.1 Description of CTL Process 351 9.2.2 Mass Balance and Energy Analysis 353 9.2.3 Exergy Analysis 354 9.3 Exergy Analysis of Gas-to-Liquid (GTL) Processes 355 9.3.1 GTL Process with Tail Gas Recycling: Internal and External 356 9.3.2 Impact of Reformer Temperature on GTL Efficiency: External Tail Gas Recycling 361 9.4 Exergy Analysis of Biomass-to-Liquid (BTL) Processes 365 9.4.1 Introduction 365 9.4.2 Once-Through F-T Process 366 9.4.3 Impact of Biomass Feedstock on Process Efficiency 373 9.4.4 Reforming and Recycling of F-T Reactor Tail Gas 377 9.4.5 Recycling of F-T Reactor Tail Gas to Biomass Gasifier 382 9.5 Closing Remarks 383 References 383 Chapter 10 | Methanol 387 10.1 Methanol: An Overview 387 10.1.1 Introduction 387 10.1.2 Historical Development 388 10.1.3 Chemistry 389 10.1.4 Methanol as Transport Fuel 390 10.1.5 Process Design 392 10.1.6 Process Performance 393 10.2 Methanol from Fossil Fuels 396 10.2.1 Methanol from Natural Gas 396 10.2.2 Methanol from Coal 400 10.3 Methanol from Biomass 405 10.3.1 Methanol from Waste Biomass (Sewage Sludge) 405 10.3.2 Other Biomass-Based Methanol Processes 413 10.4 Closing Remarks 414 References 415 Chapter 11 | Thermochemical Ethanol 419 11.1 Thermochemical Ethanol: An Overview 419 11.1.1 Introduction 419 11.1.2 Process Chemistry 420 11.1.3 Catalysts for Ethanol Synthesis 422 11.1.4 Process Design 423 11.1.5 Energy, Environmental and Economic Aspects 426 11.2 Exergy Analysis 427 11.2.1 Process Description 428 11.2.2 Mass and Energy Balances (Rh-Based Catalyst) 431 11.2.3 Exergy Analysis (Rh-Based Catalyst) 433 11.2.4 Impact of Ethanol Synthesis Catalyst (MoS2-Based Target Catalyst) 435 11.2.5 Impact of Gasification Temperature 438 11.3 Closing Remarks 439 References 440 Chapter 12 | Dimethyl Ether (DME) 445 12.1 Dimethyl Ether: An Overview 445 12.1.1 Introduction 445 12.1.2 Historical Development 446 12.1.3 Process Chemistry 447 12.1.4 DME as Energy Carrier 448 12.1.5 Production Technology 449 12.1.6 Energy, Environmental, and Economic Aspects 451 12.2 Dimethyl Ether from Fossil Fuels 452 12.2.1 DME from Natural Gas 452 12.2.2 DME from Coal 458 12.2.3 DME from Co-Feed of Natural Gas and Coal 462 12.3 Dimethyl Ether from Biomass 462 12.3.1 DME via Indirect Steam Gasification 462 12.3.2 Influence of Syngas Preparation Method on Process Efficiency 468 12.4 Closing Remarks 472 References 472 Chapter 13 | Hydrogen 475 13.1 Hydrogen: An Overview 475 13.1.1 Introduction 475 13.1.2 History: from Discovery to Hydrogen Economy 476 13.1.3 Chemistry of Hydrogen Production 477 13.1.4 Hydrogen Use 479 13.1.5 Hydrogen Storage 480 13.1.6 Production Methods 481 13.1.7 Energy, Environmental, and Economic Performance 482 13.2 Exergy Analysis of Hydrogen from Fossil Fuels 485 13.2.1 Hydrogen from Natural Gas 485 13.2.2 Comparison of Efficiency for Hydrogen-from-Natural Gas Processes 489 13.2.3 Hydrogen-from-Coal Gasification 490 13.2.4 Comparison of Efficiency for Hydrogen-from-Coal Processes 493 13.3 Exergy Analysis of Hydrogen from Water Electrolysis 494 13.3.1 Process Description 494 13.3.2 Mass and Energy Balances 495 13.3.3 Exergy Analysis 495 13.4 Exergy Analysis of Future Hydrogen Production Processes 496 13.4.1 Thermochemical Cycles 497 13.4.2 Geothermal Energy 499 13.4.3 Solar Energy 500 13.5 Exergy Analysis of Hydrogen Production from Biomass Gasification 501 13.5.1 Exergy Analysis of Hydrogen from Wood 501 13.5.2 Influence of Biomass Feedstocks on Exergetic Efficiency 506 13.5.3 Influence of Gasification System Configurations on Exergetic Efficiency 507 13.5.4 Comparison of Efficiency for Hydrogen-from-Biomass Gasification 511 13.6 Exergy Analysis of Biological Hydrogen Production 512 13.6.1 Process Description 512 13.6.2 Mass and Energy Balances 514 13.6.3 Exergy Analysis 515 13.7 Closing Remarks 517 References 517 Chapter 14 | Substitute Natural Gas (SNG) 523 14.1 Substitute Natural Gas: An Overview 523 14.1.1 Introduction 523 14.1.2 Historical Development 524 14.1.3 Chemistry of Methanation 526 14.1.4 Natural Gas as Energy Carrier 527 14.1.5 SNG Production Technology 529 14.1.6 Energy, Environmental and Economic Aspects 530 14.2 SNG from Coal 533 14.2.1 Description of Coal-to-SNG Process 533 14.2.2 Process Modeling 537 14.2.3 Mass and Energy Balances 537 14.2.4 Exergy Analysis 538 14.2.5 Overview of Coal-to-SNG Processes 540 14.3 SNG from Biomass Gasification 540 14.3.1 SNG via Wood Gasification 540 14.3.2 Comparison of SNG Production from Various Biomass Feedstocks 550 14.3.3 Overview of Biomass-to-SNG Processes 555 14.4 Closing Remarks 555 References 556 PART IV | Bioenergy Systems Chapter 15 | Thermal Power Plants, Heat Engines, and Heat Production 561 15.1 Biomass-Based Power and Heat Generation: An Overview 561 15.1.1 Introduction 561 15.1.2 Historical Development 563 15.1.3 Technologies for Power Generation from Biomass 564 15.1.4 Biofuels in Internal Combustion Engines and Gas Turbines 567 15.1.5 Biomass Heating Systems 568 15.1.6 Performance and Cost of Power Generation Systems 569 15.1.7 Environmental Aspects 571 15.2 Biomass Combustion Power Systems 571 15.2.1 Introduction 571 15.2.2 Biomass Steam Cogeneration Plant 572 15.2.3 Externally Fired Gas Turbine–Combined Cycle 575 15.2.4 Biomass-Fired Organic Rankine Cycle (ORC) 580 15.3 Biomass Gasification Power Systems 584 15.3.1 Introduction 584 15.3.2 Biomass Integrated Gasification Gas Turbine–Combined Cycle (BIG/GT-CC) 585 15.3.3 Improving Efficiency BIG/GT-CC Plants 588 15.3.4 Biomass Integrated Gasification Internal Combustion Engine–Combined Cycle (BIG/ICE-CC) 589 15.4 Comparison of Various Biomass-Fueled Power Plants 591 15.4.1 Internally and Externally Fired Gas Turbine Simple Cogeneration Cycles 592 15.4.2 Internally and Externally Fired Gas Turbine: Simple and Combined Cycles 597 15.4.3 Comparison of Biomass Combustion and Gasification CHP Plants 602 15.5 Biomass-Fueled Internal Combustion Engines and Gas Turbines 608 15.5.1 Ethanol-Fueled Spark-Ignition Engines 609 15.5.2 Biodiesel-Fueled Compression-Ignition Engines 610 15.5.3 Biofuel-Fired Gas Turbines 612 15.6 Polygeneration of Electricity, Heat, and Chemicals 615 15.6.1 Introduction 615 15.6.2 Methanol Synthesis 615 15.6.3 Ethanol Production 621 15.7 Biomass Boilers and Heating Systems 624 15.7.1 Introduction 624 15.7.2 Biomass Boilers 625 15.7.3 Energy Utilization in Buildings 627 15.8 Closing Remarks 628 References 628 Chapter 16 | Biomass-Based Fuel Cell Systems 633 16.1 Biomass-Based Fuel Cell Systems: An Overview 633 16.1.1 Introduction 633 16.1.2 Historical Development 634 16.1.3 Fuel Cell Fundamentals 635 16.1.4 Fuel Cell Types 636 16.1.5 Fuel Cell Thermodynamics 638 16.1.6 Overview of Biomass-Based Fuel Cell Configurations 640 16.1.7 Energy Efficiency, Cost, and Environmental Impact 642 16.2 Biomass Integrated Gasification–Solid Oxide Fuel Cell (BIG/SOFC) Systems 642 16.2.1 Central Power Production Using BIG/SOFC/GT Systems 643 16.2.2 Other Central Power Production Studies Using BIG/SOFC Systems 647 16.2.3 Distributed Power Production Using BIG/SOFC Systems 648 16.2.4 Integration of Supercritical Water Gasification (SCWG) with SOFC/GT Hybrid System 650 16.3 Biomass Integrated Gasification–Proton Exchange Membrane Fuel Cell (BIG/PEMFC) Systems 652 16.3.1 Distributed Combined Heat and Power Generation Based on Central Hydrogen Production 652 16.3.2 Effect of Hydrogen Quality on Efficiency of Distributed CHP Systems 659 16.4 Fuel Cell Systems Fed with Liquid Biofuels 660 16.4.1 Introduction 660 16.4.2 Maximum Electricity Obtainable from Various Fuels 661 16.4.3 Integrated Fuel Processor–Fuel Cell (FP-FC) System 663 16.4.4 Direct Liquid Fuel Cell Systems 668 16.5 Closing Remarks 669 References 669 Chapter 17 | Biorefineries 673 17.1 Biorefineries: An Overview 673 17.1.1 Introduction 673 17.1.2 Historical Development 674 17.1.3 Chemical Value of Biomass 675 17.1.4 Biorefinery Systems 677 17.1.5 Biorefinery Technology 679 17.2 Comparison of Various Biomass Utilization Routes 681 17.2.1 Biomass Utilization Routes 681 17.2.2 Power Generation 682 17.2.3 Biofuels Production 683 17.2.4 Chemical Biorefinery 683 17.3 Exergy Inputs to Basic Biorefinery Steps 684 17.3.1 Biorefinery Model 684 17.3.2 Processing Simple Carbohydrates into Fermentable Sugars 686 17.3.3 Processing Complex Carbohydrates into Fermentable Sugars 686 17.3.4 Processing Fermentable Sugars into Ethanol 688 17.3.5 Processing Ethanol into Ethylene 689 17.3.6 Fatty Acids Processing 690 17.3.7 Amino Acids Processing 692 17.3.8 Lignin Processing 695 17.3.9 Ash and Residuals Processing 695 17.4 Optimal Biomass Crops as Biorefinery Feedstock 696 17.4.1 Biomass versus Petrochemical Route for the Production of Bulk Chemicals 696 17.4.2 Cumulative Fossil Fuel Consumption in the Biomass Route 697 17.4.3 Cumulative Fossil Fuel Consumption in the Petrochemical Route 698 17.4.4 Fossil Fuel Savings 699 17.4.5 Optimal Crops for Biorefineries 699 17.5 Closing Remarks 702 References 702 Postface 707 Appendixes Appendix A – Conversion Factors 709 Appendix B – Constants 711 Appendix C – SI Prefixes 713 Glossary of Selected Terms 715 Notation 721 Acknowledgments for Permission to Reproduce Copyrighted Material 729 Author Index 733 Subject Index 745