Hydrogen Sulfide Removal from Hot Gas and Concentration of Sulfur Using Electrochemistry. Annual Report August 1983 - August 1984

摘要

The virtual omnipresence of sulfur in fossil fuels raises concern regarding the increased use of coal for high temperature fuel utilization and conversion processes. A typical raw gas composition from burning Illinois No. 6 coal (3.9% sulfur) in an air-blown gasifier is 19.6% CO, 8.1% CO2, 10%H2, 3.4%H2o, 3% Ch4, 0.6% H2 S with the balance being inerts. This gas has several potential uses. Of most interest is its conversion to high-BTU SNG which requires passage over a methanation catalyst at 300-400C. The methanation catalysts, however, are sensitive to even small (5ppm) concentrations of H2S. Thus, in the absence of a very effective high-temperature sulfur clean-up process, the gas must be cooled to the temperatures of operation of commercially available processes (e.g., Selexol or Rectisol). The use of high-temperature clean-up is estimated to allow savings of up to 7% of the energy value of the gas. Since a high-temperature sulfur removal process is desirable several have undergone examination. Most are based on reaction of a metal oxide with the H2S, with subsequent regeneration to the fresh sorbent and a concentrated stream of H2S. This H2S is then sent to a Claus Plant to be oxidized to elemental sulfur (and water). Difficulties of various kinds have not permitted any of these processes from as yet reaching commercialization. Grainger, L. and J. Gibson, 'Coal Utilization', New York: Wiley, 1981' Wen, C.Y. and E.S. Yee, 'Coal Conversion Technology', London: Addison-Wesley, 1979.