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Title: Methanation feed gas carbon dioxide level. Final report. Series No. I: E-6. [CO/sub 2/ removal upstream or downstream from methanation]

Abstract

Coal gasification yields a gas which is mainly hydrogen, carbon monoxide, methane, and carbon dioxide. For the product gas to be acceptable as a substitute for natural gas, it must contain less than 0.1 percent carbon monoxide and no more than about 3 percent carbon dioxide. To meet these limits, carbon monoxide is converted to methane, and carbon dioxide is removed from the gas. Sulfur compounds must be removed upstream of the methanation unit because the methanation catalyst is poisoned by sulfur. By changes in the design of the acid-gas-removal unit all, or part, of the CO/sub 2/ can be removed with the H/sub 2/S. As the amount of CO/sub 2/ removal is decreased, the equipment and operating costs in the acid-gas-removal unit also decrease. It may be less costly to remove CO/sub 2/ downstream of methanation because the volumetric shrinkage during methanation increases the partial pressure of the CO/sub 2/. This change in partial pressure could reduce capital and operating costs compared to acid-gas removal at the lower CO/sub 2/ partial pressure before methanation. Determination of the amount of CO/sub 2/ which should be removed downstream of methanation should be based on process economics. The process units involved aremore » acid-gas removal, methanation, and product drying. This study compares the costs of designs of these process units for various levels of CO/sub 2/ in the methanation feed gas. In this study, we looked at methanation feed CO/sub 2/ levels of 1, 8, 14, and 20 percent. If the CO/sub 2/ level is 1 percent, then all of the CO/sub 2/ removal is done upstream of methanation. If the CO/sub 2/ level is greater than 1 percent, then a final CO/sub 2/ removal unit and a trim methanator will be required after bulk methanation. The results of this study indicate that maximum CO/sub 2/ removal upstream of methanation without the final CO/sub 2/ cleanup is less costly.« less

Authors:
Publication Date:
Research Org.:
Braun (C.F.) and Co., Alhambra, Calif. (USA)
OSTI Identifier:
6773465
Report Number(s):
FE-2240-45
DOE Contract Number:  
EX-76-C-01-2240
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; CARBON DIOXIDE; REMOVAL; HIGH BTU GAS; SPECIFICATIONS; HYDROGEN SULFIDES; ORGANIC SULFUR COMPOUNDS; SYNTHESIS GAS; CHEMICAL COMPOSITION; METHANATION; PURIFICATION; CARBON MONOXIDE; COAL GASIFICATION; ECONOMICS; ENGINEERING; FEASIBILITY STUDIES; METHANE; ALKANES; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHEMICAL REACTIONS; CRYOGENIC FLUIDS; ENERGY SOURCES; FLUIDS; FUEL GAS; FUELS; GAS FUELS; GASES; GASIFICATION; HYDROCARBONS; HYDROGEN COMPOUNDS; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; SULFIDES; SULFUR COMPOUNDS; 010404* - Coal, Lignite, & Peat- Gasification; 010402 - Coal, Lignite, & Peat- Purification & Upgrading

Citation Formats

Leu, J. C. Methanation feed gas carbon dioxide level. Final report. Series No. I: E-6. [CO/sub 2/ removal upstream or downstream from methanation]. United States: N. p., 1977. Web. doi:10.2172/6773465.
Leu, J. C. Methanation feed gas carbon dioxide level. Final report. Series No. I: E-6. [CO/sub 2/ removal upstream or downstream from methanation]. United States. https://doi.org/10.2172/6773465
Leu, J. C. Sat . "Methanation feed gas carbon dioxide level. Final report. Series No. I: E-6. [CO/sub 2/ removal upstream or downstream from methanation]". United States. https://doi.org/10.2172/6773465. https://www.osti.gov/servlets/purl/6773465.
@article{osti_6773465,
title = {Methanation feed gas carbon dioxide level. Final report. Series No. I: E-6. [CO/sub 2/ removal upstream or downstream from methanation]},
author = {Leu, J. C.},
abstractNote = {Coal gasification yields a gas which is mainly hydrogen, carbon monoxide, methane, and carbon dioxide. For the product gas to be acceptable as a substitute for natural gas, it must contain less than 0.1 percent carbon monoxide and no more than about 3 percent carbon dioxide. To meet these limits, carbon monoxide is converted to methane, and carbon dioxide is removed from the gas. Sulfur compounds must be removed upstream of the methanation unit because the methanation catalyst is poisoned by sulfur. By changes in the design of the acid-gas-removal unit all, or part, of the CO/sub 2/ can be removed with the H/sub 2/S. As the amount of CO/sub 2/ removal is decreased, the equipment and operating costs in the acid-gas-removal unit also decrease. It may be less costly to remove CO/sub 2/ downstream of methanation because the volumetric shrinkage during methanation increases the partial pressure of the CO/sub 2/. This change in partial pressure could reduce capital and operating costs compared to acid-gas removal at the lower CO/sub 2/ partial pressure before methanation. Determination of the amount of CO/sub 2/ which should be removed downstream of methanation should be based on process economics. The process units involved are acid-gas removal, methanation, and product drying. This study compares the costs of designs of these process units for various levels of CO/sub 2/ in the methanation feed gas. In this study, we looked at methanation feed CO/sub 2/ levels of 1, 8, 14, and 20 percent. If the CO/sub 2/ level is 1 percent, then all of the CO/sub 2/ removal is done upstream of methanation. If the CO/sub 2/ level is greater than 1 percent, then a final CO/sub 2/ removal unit and a trim methanator will be required after bulk methanation. The results of this study indicate that maximum CO/sub 2/ removal upstream of methanation without the final CO/sub 2/ cleanup is less costly.},
doi = {10.2172/6773465},
url = {https://www.osti.gov/biblio/6773465}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1977},
month = {10}
}