Adsorptive removal of dimethyl sulfide from biogas for solid oxide fuel cell applications

• Six commercial sorbents were studied for adsorptive removal of dimethyl sulfide. • CuO-functionalized activated carbon was the most robust to changes in moisture. • While Cu-Z was more robust to the presence of terpenes in the gas, it is strongly affected by moisture. • Terpene/VOC management is necessary for trace sulfur removal from biogas. Reliable desulfurization is needed to bring the total sulfur content in biogas to below 1 ppm v or even lower in many catalytic processes such as fuel cells. In practice, this means that consistent methods must be developed for the removal of trace sulfur compounds (especially dimethyl sulfide), which are generally more difficult to remove and not as well studied as H 2 S, the primary sulfur compound in biogas. In this work, experiments are performed in the laboratory with a simulated biogas. Five commercial activated carbons with various functionalization and one commercial zeolite are studied for adsorptive removal of dimethyl sulfide in the presence of varying levels of common biogas trace compounds. It is shown that sorbents, which may remove dimethyl sulfide well in simple gas mixtures (single contaminant, dry gas) behave differently if the realities of biogas mixtures (variable humidity, variable co-contaminants) are taken into account, and that these effects occur to different extents in different sorbents. While the zeolite removed dimethyl sulfide consistently even in the presence of terpenes in the gas, its dimethyl sulfide capacity was lost in high-moisture gas. Meanwhile, a CuO-functionalized activated carbon was the most robust to changes in moisture, but all the activated carbons were susceptible to competitive adsorption from terpenes. Based on these results, recommendations are made about the choice of biogas sorbents for dimethyl sulfide removal, and techno-economic implications are discussed.