Gasification Technologies - A Primer for Engineers and Techs

338 Pages·2005·5.192 MB·English

by  J. Rezaiyan, N. Cheremisinoff

Gasification
Technologies
A Primer for Engineers and Scientists
John Rezaiyan
Nicholas P. Cheremisinoff
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Table of Contents
Chapter 1 Principles of Gasification........................................... 1
Introduction........................................................................................ 1
Historical Perspective and Commercialization Trends................... 2
Historical Perspectives.............................................................. 2
Renewed Interest and the Incentives for Commercialization... 3
Commercialization Growth and Today’s Applications ............ 4
Gasification Principles....................................................................... 5
Overview .................................................................................... 5
Hydrogenation ........................................................................... 7
Stoichiometric Considerations.................................................. 7
Gasification Versus Combustion ..................................................... 10
Comparisons of General Features.......................................... 10
Environmental Controls.......................................................... 10
Solid Byproducts...................................................................... 13
Advantages of Gasification over Combustion........................ 14
Stoichiometries and Thermodynamics............................................ 16
Drying....................................................................................... 17
Devolatilization........................................................................ 17
Gasification .............................................................................. 17
Combustion .............................................................................. 18
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Gasification Kinetics........................................................................ 20
Biomass Gasification........................................................................ 23
Overview .................................................................................. 23
Types of Biomass Gasifiers..................................................... 24
Biomass Characteristics.......................................................... 25
Petroleum Coke Gasification........................................................... 27
References......................................................................................... 30
Recommended Resources................................................................. 32
Chapter 2 Coal Gasification Technologies................................ 35
Introduction...................................................................................... 35
Coal Gasification .............................................................................. 36
Overview .................................................................................. 36
Types of Coal ........................................................................... 36
Composition and Structure..................................................... 38
Characteristics......................................................................... 39
Gasifier Configurations.................................................................... 40
Gasifier Classification ............................................................. 40
Entrained Flow Technologies .......................................................... 41
Fluidized-bed Technologies.............................................................. 54
Moving-bed Technologies................................................................. 62
Technology Suppliers ....................................................................... 64
Syngas Characteristics .................................................................... 64
Gas Cleanup Systems ............................................................. 65
Technology Suppliers for Particulate Removal.............................. 67
Sulfur Removal........................................................................ 67
The Power Block...................................................................... 68
Comparisons Between Technologies....................................... 68
Syngas Applications and Technology Selection Criteria............... 68
Integrated Gasification Combined Cycle............................... 81
Operational Feedback.............................................................. 85
Investment Costs..................................................................... 86
Guide to Commercial Experience ................................................... 86
Chapter 3 Biogasification......................................................... 119
Introduction.................................................................................... 119
Overview ......................................................................................... 119
Technology Advantages.................................................................. 120
General Applications...................................................................... 121
Commercial Systems...................................................................... 121
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Contaminants ................................................................................. 127
Formation of Tars........................................................................... 130
Ammonia Formation ...................................................................... 131
No Formation................................................................................ 132
X
Sulfur .............................................................................................. 132
Hydrogen Production from Biomass............................................. 133
Recommended Resources............................................................... 140
EndNotes ........................................................................................ 143
Chapter 4 Pyrolysis.................................................................. 145
Introduction.................................................................................... 145
Pyrolysis Principles........................................................................ 147
General................................................................................... 147
Effect of Heating Rate .......................................................... 149
Effect of Temperature ........................................................... 150
Applications .................................................................................... 152
Large-scale Commercial Processes for Mixed Solid Waste ... 152
Application to Contaminated Soil Remediation.................. 157
Treatment of Municipal Solid Waste ................................... 158
Treatment of Medical Waste................................................. 159
Plasma Torches and Plasma Pyrolysis ................................ 160
EndNotes ........................................................................................ 164
Chapter 5 Gas Cleanup Technologies..................................... 165
Introduction.................................................................................... 165
Overview of Particulate Removal Technologies........................... 165
Particulate Collection Technologies .............................................. 170
Gravity Settling Chambers................................................... 170
Cyclone Separators................................................................ 177
Fabric Filter Pulse Jet-Cleaned Type .................................. 185
Dry Electrostatic Precipitator: Wire-Pipe Type .................. 193
Wet Electrostatic Precipitator: Wire-Pipe Type and
Others........................................................................ 200
Venturi Scrubbers.................................................................. 208
Orifice Scrubber..................................................................... 214
Condensation Scrubbers ....................................................... 219
Gas Conditioning Technologies ..................................................... 221
Packed Tower and Absorption .............................................. 222
Impingement-Plate/Tray Tower Scrubbers.......................... 231
Fiber-Bed Scrubbers.............................................................. 236
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Activated Carbon and Other Adsorber Systems.......................... 239
Thermal Destructive Technologies................................................ 247
Recommended Resources............................................................... 265
Chapter 6 Integration of Gasification Technologies .............. 271
Introduction.................................................................................... 271
Role of Coal Gasification ............................................................... 271
Gas Turbine Technologies.............................................................. 282
Fuel Requirements......................................................................... 286
Use of Coal-Derived Liquid Fuel.......................................... 287
Market Trends................................................................................ 289
R&D Needs..................................................................................... 294
Improved Operational Performance..................................... 294
Improved Efficiencies ............................................................ 294
Fuel Cell Technology Development Status .................................. 298
Integrated Gasification Fuel Cell Power
Systems Requirements............................................. 305
Integrated Gasification Fuel Cell Hybrid Power Systems
Requirements............................................................ 307
System Configurations and Costs ........................................ 309
Fuel Processing Technology........................................................... 313
Technology Integration with Coal Gasification ........................... 313
Hybrid Systems.............................................................................. 315
Fuel Cell Technology and System Integration Issues................. 317
Areas for Technical Development......................................... 318
Large-Scale Distributed Power, Industrial Cogeneration, and
Central Generation................................................................ 319
Gasification Technology Development and System Integration
Issues...................................................................................... 320
Recommended Resources............................................................... 328
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Preface
Gasification technologies offer the potential of clean and efficient
energy. The technologies enable the production of synthetic gas from
low or negative-value carbon-based feedstocks such as coal, petro-
leum coke, high sulfur fuel oil, materials that would otherwise be
disposed as waste, and biomass. The gas can be used in place of
natural gas to generate electricity, or as a basic raw material to
produce chemicals and liquid fuels.
Gasification is a process that uses heat, pressure, and steam to
convert materials directly into a gas composed primarily of carbon
monoxide and hydrogen. Gasification technologies differ in many
aspects but rely on four key engineering factors:
1. Gasification reactor atmosphere (level of oxygen or air
content)
2. Reactor design
3. Internal and external heating
4. Operating temperature
The feedstock is prepared and fed, in either dry or slurried form,
into a reactor chamber called a gasifier. The feedstock is subjected
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to heat, pressure, and either an oxygen-rich or oxygen-starved envi-
ronment within the gasifier. All commercial gasifiers require an
energy source to generate heat and begin processing.
There are three primary products from gasification:
• Hydrocarbon gases (also called syngas)
• Hydrocarbon liquids (oils)
• Char (carbon black and ash)
Syngas can be used as a fuel to generate electricity or steam, or
as a basic building block for a multitude of chemicals. When mixed
with air, syngas can be used in gasoline or diesel engines with few
modifications to the engine.
Both pyrolysis and gasification convert carbonaceous materials
into energy-rich fuels by heating the feedstock under controlled
conditions. Whereas incineration fully converts the input material
into energy and ash, these processes deliberately limit the conver-
sion so that combustion does not take place directly. Instead, they
convert the material into valuable intermediates that can be further
processed for materials recycling or energy recovery.
Gasification in particular offers more scope for recovering prod-
ucts from waste than incineration. When waste is burned in a modern
incinerator the only practical product is energy, whereas the gases,
oils, and solid char from gasification can not only be used as a fuel
but also be purified and used as a feedstock for petro-chemicals and
other applications. Gasification can be used in conjunction with gas
engines and gas turbines to obtain higher conversion efficiency than
conventional fossil-fuel electric power generation. In contrast, con-
ventional incineration, used in conjunction with steam-cycle boilers
and turbine generators, achieves lower efficiency. Gasification can help
meet renewable energy steam targets, address concerns about global
warming, and contribute to achieving Kyoto Protocol commitments.
There are more than 150 companies around the world that are
marketing systems based on gasification concepts. Many of these
are optimized for specific wastes or particular scales of dedicated
energy production operations. They vary widely in the extent to
which they are proven in operation. In addition, there are more than
100 facilities operating around the world.
This book serves as a primer to coal and biomass gasification
technologies. It is meant as an introduction and overview of current
technology developments, and to provide readers with a general
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Preface xix
understanding of the technology challenges for large-scale commer-
cialization. While there is an abundant source of literature both on
the World Wide Web and in printed form, the information and
experiences in development and commercialization are fragmented.
This volume helps to place the technology and research and devel-
opment challenges into perspective.
Nicholas P. Cheremisinoff, Ph.D.
A. John Rezaiyan
Princeton Energy Resources International, LLC
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About The Authors
Nicholas P. Cheremisinoff has 30 years of industry and applied
research and development experience throughout the petrochemical
and allied industries. His assignments have focused on implemen-
tation of clean technologies for manufacturing and energy production,
with experiences ranging from fossil energy to biomass and wind
energy applications. He has worked extensively on overseas assign-
ments for donor agencies such as the United States Agency for
International Development, for international lending institutions
including the World Bank Organization, and for numerous private
sector clients. He is the author, co-author, or editor of more than
100 technical books. Dr. Cheremisinoff received his B.Sc., M.Sc., and
Ph.D. degrees in chemical engineering from Clarkson College of
Technology.
A. John Rezaiyan is Vice President for Advanced Engineering
Group at Princeton Energy Resources International LLC (PERI).
He has 25 years of experience in fluidized-bed combustion and
gasification technology development. He works closely with technology
developers, project developers, government agencies, and financial
institutions to assess market potential and technical, economic, and
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