Evaluation of the Wheeler-Jonas parameters for biogas trace compounds removal with activated carbons

A practical and feasible solution to reduce the global impacts from fossil fuels is represented by the locally distributed micro-cogeneration systems with high temperature solid oxide fuel cells (SOFC) fed by biogenous fuel coupled in an energy distributed system. One of the main drawback is the low tolerability towards certain fuel impurities, mostly sulfur, chlorine and siloxane compounds. The opportunity to predict the breakthrough time of a gas cleaning section with a high precision level is mandatory to meet SOFC requirements. The reaction kinetic equation called the Wheeler-Jonas equation is adopted to estimate this breakthrough time. Two different commercial activated carbons were studied estimating the breakthrough time varying the operating temperature, the pollutant concentration (single and multiple effects) and the relative humidity. Results showed how relative humidity content affects inversely the removal performance for both sorbents. The Carbox sample, below RH 20% showed interesting results due to its metals content and microstructure. Here, relative humidity promoted the best condition to remove organic vapors from the biogas stream. Multiple contaminant conditions for both sorbent materials decreased the removal performance (tb). This decreasing for the Carbox sample ranged from a minimum of 44% to a maximum of 50% for H2S, and 70% for HCl with wet and dry conditions respectively.