Regenerable Sorbent System to Cleanup Biogas for Fuel Cell CHP Systems

摘要

The relatively small, distributed fuel cell CHP systems that uses the biogas generated from opportunity fuels such as crop residues, farm waste, municipal solid waste, food processing wastes, etc present a realistic, neat-term solution for large energy efficiency improvements and significant reduction in CO2 emissions. In addition to CO2 and CH4, the biogas generated in the digesters and fermentation units contains various contaminants such as H2S, organic sulfides and disulfides that must be removed to prevent degradation of the fuel cell plant performance. Depending on the biomass feedstock and digester design, the concentration of the higher sulfide species ranges from 0.1 ppmv to as high as 30 ppmv. The existing bulk desulfurization processes are designed to remove H2S, and do very little to remove the organic sulfur compounds. Hence, TDA Research Inc. (TDA) is developing low-cost, regenerable sorbent that can remove both H2S and organic sulfur species in biogas to the ppb levels in a single step. The sorbent beds are regenerable and can be regenerated using a temperature swing in air. These sorbents also would find application in desulfurizing other gas streams such as landfill gas, natural gas, LPG and refinery off-gases.