Study of catalytic systems for the abatement of CH4 emissions from geothermal processes

Geothermal energy is one of the most environmentally-friendly and cost-effective energy sources with potential to replace fossil fuels and help mitigate global warming as well. The geothermal energy mainly consists of steam or hot water which contains harmful substances, such as CO2, H2S, NH3, CH4 and small amount of other species (e.g., Hg, NaCl, As). To reduce the emissions, Enel has patented a special process named AMIS (Abbattimento di Mercurio e Idrogeno Solforato), which allows the abatement of mercury and hydrogen sulphide. Between these sucstances, methane has a a stronger effect on global warming (GWPmethane=21) compared to carbon dioxide, therefore it is necessary to prevent as much as possible its emissions into the atmosphere by using appropriate abatement systems. For this reason, ENEL has targeted to develop, in cooperation with Politecnico di Milano, an improved version of AMIS able to reduce CH4 emission in exhaust gases. Within this framework this thesis work has investigated the performances of a commercial Pt-based catalyst before and after the use in a pilot scale facilities located in an Enel plant. The scope was to obtain a better understanding of the observed catalyst performances and of their modifications during the pilot testing campaign so to get preliminary information for the design of the industrial reactor.