Adsorptive removal of H2S in biogas conditions for high temperature fuel cell systems

Desulfurization represents a crucial step in fuel processing for high temperature fuel cells, because of catalysts stringent requirements. Moreover, when fuel cell stacks are used in micro-CHP applications, it is necessary to build an efficient and compact system. The use of biogas from anaerobic digestion could have a significant impact in terms of fossil fuels saving and environmental conservation. Biogas contains different impurities, among which H2S represents one of the most harmful components.

Adsorption tests for H2S removal were carried out in biogas conditions, using commercial adsorbents, defining the materials characterized by the best performance and resulting in a predominance of impregnated activated carbons. The influence on adsorption capacity of operating parameters, such as gas hourly space velocity, gas matrix composition (N2, CH4 and CO2), humidity, temperature (30–150 °C), H2S concentration (50–1000 ppmv) and filter geometry, was investigated. The aim of the study was the functional parameters optimization to obtain a compact filter with high removal activity.