Optimizing Hydrogen Sulfide Removal and Biogas Production Using the Water Wash Method

Abstract

Biogas forms from decomposing organic material in agricultural digesters, landfills, and wastewater treatment plant digesters. Biogas is mostly composed of methane, and can be used as a carbon-based fuel. Microorganisms that consume organics in these waste streams also produce hydrogen sulfide (H2S) as part of the biogas, in varying trace amounts. H2S is corrosive to engines and pipes for machinery, a human health hazard when inhaled, and an aquatic hazard when dissolved in water. Water washing is an absorption process that dissolves hydrogen sulfide and other water soluble compounds in this process and carries it away from the gas, thereby purifying it. A water wash absorption column process at Jones Island in Milwaukee is being tested to purify landfill biogas by varying gas and water flowrates, as well as the gas pressure, resulting in an observed 90-99% removal of hydrogen sulfide from biogas was observed.