Purification of Biogas for Energy Use

Abstract

This work determined the absorption efficiency of H2S in the solution of Fe-EDTA in synthetic biogas flows, as well as the efficiency of physical absorption of CO2 in Fe-EDTA. Biogas was bubbled through a pseudo-catalytic solution of Fe-DTA resulting in the formation of sulfur particles. H2S absorbed in the Fe-EDTA suffered a redox reaction. The Fe-EDTA solution used was regenerated with air. It was used two types of catalysts, in order to compare the efficiency of a catalyst of Fe-EDTA synthesized in the laboratory in an inert atmosphere, in relation to a commercial catalyst containing Fe-EDTA. In the batch study, removing H2S from biogas indicated that the concentration of Fe-EDTA applies great influence on the catalytic activity. For a system operating in a continuous regimen, it was possible to completely eliminate the H2S from biogas with Fe-EDTA synthesized in laboratory. The removal of CO2 present in the biogas was also evaluated. It was possible to achieve maximum efficiency of the CO2 absorption in 90 % in steady state, it was obtained an increase of 16 % in the calorific value of biogas, from 8.03 to 9.28 kWh/m3.