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Coal%20Gasification%20Technology%20and%20Syngas%20Production
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Coal Gasification Technology and Syngas Production. Ruben Reyes. ChE379. Purpose/Outline ... Counter-current flow of coal and oxidizing blast ... – PowerPoint PPT presentation
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Title: Coal%20Gasification%20Technology%20and%20Syngas%20Production
1
Coal Gasification Technology and Syngas Production
- Ruben Reyes
- ChE379
2
Purpose/Outline
- Gasification technology
- Different types of gasifiers
- Products from gasification
- Syngas production, Gasifiers used for IGCC power
plants - Conclusion
3
Coal Gasification Technologies
- Basic Overview of gasification
- Coal or other fuels
- Oxidation carefully controlled
- H2, CO2, CH4, other products
- H2 can be purified
- Ash/slag leftovers
- 3 types of gasifiers
- Moving bed
- Fluid Bed
- Entrained Flow
- Underground Coal Gasification
- Vertical wells and pathway creation
- Controlled retraction injection point
4
Above ground gasification
BGL gasifier (fixed bed, slagging)
- Moving bed reactor (Lurgi dry ash and BGL -
slagging) - Counter-current flow of coal and oxidizing blast
- Blast composed of air and hot syngas, so low
oxygen consumption - Operates on reactive carbon sources
- Good heat transfer heats the carbon source
creating methane and tar - Post production cleaning and scrubbing requires
greater energy use
Figure 1 BGL Gasifier
5
Above Ground Gasification
Winkler Gasifier (Fluid bed, dry ash)
- Fluid-bed reactor (Winkler, HTW, CFB dry ash
KRW, U-Gas Agglomerating) - Air fluidizes a bed and carbon containing
particles added - Proper mixing of fuel and oxidant provide good
mass transfer and heat transfer - Fine particle will escape with syngas and needs
to be cleaned - Very good heat/mass transfer so partially reacted
carbon may settle with ash - Slagging will reduce fluidization, so temp
remains below softening point for ash
Figure 2 Winkler Gasifier
6
Above Ground Gasification
Texaco Gasifier (entrained flow, slagging)
- Entrained flow reactors (Shell, Texaco, E-gas,
Noell, KT - Slagging) - Carbon source is made of very fine particles in a
liquid or slurry for very good mass transfer - Very little residence time
- Co-current flow with oxygen where high
temperatures can be reached - Low heat transfer means hot exiting gas with no
methane or tar, but more oxygen required. - High temperature and very small carbon sources
make it an ideal process for coal gasification. - High temperatures without charring
- No agglomeration because of fine particle size
preparation
Figure 1 Texaco Gasifier
7
Underground Coal Gasification
- Vertical wells, soviet technology
- H2 and O2 are injected and ignited to create
syngas, CO2 and methane - Coal deposits do not allow for transport of the
gases from the injection well to recovery well
very easily - Closely spaced wells and reverse combustion
methods are employed to create a cavity between
wells - This process works, but requires many wells to be
constructed
Figure 5 Current UGC
8
Underground Coal Gasification
- Controlled retraction injection point from oil
technology (CRIP) - The oil industrys horizontal drilling for
production and injection wells to deliver and
absorb syngas continuously - Only one injection well, the ignition continues
through the inseam as the injection wells are
retreated. - The product is collected in a product well
- Concerns about ground water inhibit the use of
UCG.
Figure 6 CRIP UGC
9
Syngas production and energy industry
- CO2 removal
- Used for oil reclamation
- Can be injected back in ground
- Combined cycle
- Combustion turbine
- Heat used for generating steam
- Fuel cell uses
10
Conclusions
- There are many ways that carbon containing
compounds may be gasified - Coal gasification occurs best in entrained flow
reactors such as the Texaco gasifier - The coal will not heat up as much and will not
create methane and tar. - The requirement for fine particles into the
gasifier prevents agglomeration - Underground coal gasification technology is
present and used today but with certain
challenges - Water contamination
- Impact on environment and land
- Potential benefits are many
- Syngas used in combined cycle energy production
- Hydrogen fuel cell use for energy production and
transportation purposes - Methane and hydrogen have applications in the
chemical industry where they can be used. - Not mentioned, gasification is first step in coal
liquefaction process. - Coal gasification could reduce dependence on
foreign oil - CO2 sequestration
11
References
- Gasification reference shelf - images and photos.
(n.d.). National Energy Technology
Laboratory. Retrieved November 20, 2007, from
http//www.netl.doe.gov/technologies/coalpower/gas
ification/pubs/photo.html - Gasification Technology and RD. (n.d.). U.S.
Department of energy. Retrieved November 20,
2007, from http//www.fossil.energy.gov/programs/p
owersystems/gasification/index.htm - l Higman, C., Van Der Burgt, M. (n.d.).
Gasification. Elsevier. Retrieved November 20,
2007, from Google Book Search database
http//books.google.com.ezproxy.lib.utexas.edu/
books?idZUlRaUrX8IUCprintsecfrontcoverdqgas
ificationsigSxb9s5qmKK03xe9INbsiuoJwwX8PPP1,M1
- Underground Coal Gasification. (n.d.). World Coal
Institute. Retrieved November 20, 2007, from
World Coal Institute Web site
http//www.worldcoal.org/pages/content/index
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