Hybrid Molten Bed Gasifier for High Hydrogen Syngas Production [electronic resource].
- Washington, D.C. : United States. Office of the Assistant Secretary of Energy for Fossil Energy, 2017. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- 246 pages : digital, PDF file
- Additional Creators:
- Gas Technology Institute, United States. Office of the Assistant Secretary of Energy for Fossil Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- The techno-economic analyses of the hybrid molten bed gasification technology and laboratory testing of the HMB process were carried out in this project by the Gas Technology Institute and partner Nexant, Inc. under contract with the US Department of Energy’s National Energy Technology Laboratory. This report includes the results of two complete IGCC and Fischer-Tropsch TEA analyses comparing HMB gasification with the Shell slagging gasification process as a base case. Also included are the results of the laboratory simulation tests of the HMB process using Illinois #6 coal fed along with natural gas, two different syngases, and steam. Work in this 18-month project was carried out in three main Tasks. Task 2 was completed first and involved modeling, mass and energy balances, and gasification process design. The results of this work were provided to Nexant as input to the TEA IGCC and FT configurations studied in detail in Task 3. The results of Task 2 were also used to guide the design of the laboratory-scale testing of the HMB concept in the submerged combustion melting test facility in GTI’s industrial combustion laboratory. All project work was completed on time and budget. A project close-out meeting reviewing project results was conducted on April 1, 2015 at GTI in Des Plaines, IL. The hybrid molten bed gasification process techno-economic analyses found that the HMB process is both technically and economically attractive compared with the Shell entrained flow gasification process. In IGCC configuration, HMB gasification provides both efficiency and cost benefits. In Fischer-Tropsch configuration, HMB shows small benefits, primarily because even at current low natural gas prices, natural gas is more expensive than coal on an energy cost basis. HMB gasification was found in the TEA to improve the overall IGCC economics as compared to the coal only Shell gasification process. Operationally, the HMB process proved to be robust and easy to operate. The burner was stable over the full oxygen to fuel firing range (0.8 to 1.05 of fuel gas stoichiometry) and with all fuel gases (natural gas and two syngas compositions), with steam, and without steam. The lower Btu content of the syngases presented no combustion difficulties. The molten bed was stable throughout testing. The molten bed was easily established as a bed of molten glass. As the composition changed from glass cullet to cullet with slag, no instabilities were encountered. The bed temperature and product syngas temperature remained stable throughout testing, demonstrating that the bed serves as a good heat sink for the gasification process. Product syngas temperature measured above the bed was stable at ~1600oF. Testing found that syngas quality measured as H<sub>2</sub>/CO ratio increased with decreasing oxygen to fuel gas stoichiometric ratio, higher steam to inlet carbon ratio, higher temperature, and syngas compared with natural gas. The highest H<sub>2</sub>/CO ratios achieved were in the range of 0.70 to 0.78. These values are well below the targets of 1.5 to 2.0 that were expected and were predicted by modeling. The team, however, is encouraged that the HMB process can and will achieve H<sub>2</sub>/CO ratios up to 2.0. Changes needed include direct injection of coal into the molten bed of slag to prevent coal particle bypass into the product gas stream, elevation of the molten bed temperature to approximately 2500oF, and further decrease of the oxygen to fuel gas ratio to well below the 0.85 minimum ratio used in the testing in this project.
- Published through SciTech Connect., 05/23/2017., "doe-gti--12122", and David Rue.
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