Combustion and Gasification in Fluidized Beds
Features
Summary
Besides being one of the best Clean Coal Technologies, fluidized beds are also proving to be the most practical option for biomass conversion. Although the technology is well established, the field lacks a comprehensive guide to the design and operating principles of fluidized bed boilers and gasifiers. With more than 30 years of research and industrial experience, Prabir Basu answers this pressing need with Combustion and Gasification in Fluidized Beds.
This book is a versatile resource that explains how fluidized bed equipment works and how to use the basic principles of thermodynamics and fluid mechanics in design while providing insight into planning new projects, troubleshooting existing equipment, and appreciating the capabilities and limitations of the process. From hydrodynamics to construction and maintenance, the author covers all of the essential information needed to understand, design, operate, and maintain a complete fluidized bed system. It is a must for clean coal technology as well as for biomass power generation.
Beginning with a general introduction to fossil or biofuel conversion choices, the book surveys hydrodynamics, fundamentals of gasification, combustion of solid fuels, pollution aspects including climate change mitigation, heat transfer in fluidized beds, the design and operation of bubbling and circulating fluidized bed boilers, and various supporting components such as distributor grates, feeding systems, and gas-solid separators.
Table of Contents
INTRODUCTION
Background
Fluidized Bed Equipment
Features of Fluidized Beds
Fluidized Bed and Other Clean Coal Options
HYDRODYNAMICS
Regimes of Fluidization
Fast Fluidized Bed
Hydrodynamic Regimes in a CFB
Hydrodynamic Structure of Fast Beds
Gas–Solid Mixing
Scale-Up
FLUIDIZED BED GASIFICATION
Types of Gasifiers
Theory
Effect of Operating Parameters on Gasification
Effect of Feed Properties on Gasification
Fluidized Bed Gasification
Examples of Some Fluidized Bed Gasifiers
Gas Cleaning
Design Methods
Modeling of Fluidized Bed Gasification
Appendix 3A: Estimating Equilibrium Gas Composition
Appendix 3B: An Example of a Fluidized Bed Biomass Gasifier
COMBUSTION
Stages of Combustion
Factors Affecting Combustion Efficiency
Combustion in Bubbling Fluidized Bed Boilers
Combustion in Circulating Fluidized Bed Boilers
Biomass Combustion
EMISSIONS
Air Pollution
Sulfur Dioxide Emission
Nitrogen Oxide Emission
Nitrous Oxide Emission
Mercury Emission
Carbon Monoxide Emission
Carbon Dioxide Emission
Emission of Trace Organics
Particulate Emission
HEAT TRANSFER
Gas-to-Particle Heat Transfer
Heat Transfer in Circulating Fluidized Beds
Heat Transfer in Bubbling Fluidized Bed
Freeboard Heat Transfer in Bubbling Fluidized Beds
Heat Transfer in Commercial-Size CFB Boilers
BUBBLING FLUIDIZED BED BOILER
Description of a BFB Boiler
Features of BFB Boilers
Thermal Design of Bubbling Fluidized Bed Boilers
Combustion in Bubbling Fluidized Bed
Furnace Design
Start-Up Procedure and Control
Some Operational Problems and Remedies
Design of Feed Systems for BFB Bed Boiler
CIRCULATING FLUIDIZED BED BOILER
General Arrangement
Types of CFB Boilers
Non-CFB Solid Circulation Boilers
Combustion in a Circulating Fluidized Bed Furnace
Design of CFB Boilers
Furnace Design
Design of Heating Surfaces
Auxiliary Power Consumption
Control of CFB Boilers
Supercritical CFB Boiler
MATERIAL ISSUES
Material Selection Criteria
Erosion Potential
Corrosion Potentials
Steels Used in Fluidized Bed Boilers
Refractory and Insulations
Expansion Joints
SOLID HANDLING SYSTEMS FOR FLUIDIZED BEDS
Solid Handling Systems
Biomass Handling Systems
Feed System for Bubbling Beds
Feed System for Circulating Fluidized Beds
Design of Pneumatic Transport Lines for Solids
AIR DISTRIBUTION GRATE
Distributor Plates
Operation of Distributors
Design Methods
Practical Considerations
GAS–SOLID SEPARATORS
Cyclones
Impact Separator
Inertial Separators
SOLID RECYCLE SYSTEMS
Types of Non-mechanical Valves
Principles of Operation
Design of Loop-Seal
Design of L-Valve
Practical Considerations
Nomenclature
References
APPENDIX 1: CHARACTERISTICS OF SOLID PARTICLES
APPENDIX 2: STOICHIOMETRIC CALCULATIONS
APPENDIX 3: SIMPLIFIED MODEL FOR SULFUR CAPTURE
APPENDIX 4: TABLES OF DESIGN DATA
