Proton transfer reaction mass spectrometry for the gas cleaning using commercial and waste-derived materials: Focus on the siloxane removal for SOFC applications

The research efforts for SOFC plants fed by biogas moved from the prototypal research to the feasibility of pilot plants up to achieve industrial size plants. Siloxanes among the other trace compounds contained in biogas appear to be the most detrimental for the fuel cell performance. Siloxanes are difficult to be detected and monitored continuously in the gas matrix. A direct injection mass spectrometry technique (PTRMS) was adopted for the monitoring of siloxane removal. Commercial and waste derived sorbent materials are experimentally tested for the removal of siloxanes. Waste derived material was selected to implement the circular recovery purposes. A simple parametric investigation study was developed. It was considered the influence of gas velocity and sulphur compounds, as co-vapors. Physical and chemical characteristics were correlated to the adsorption capacity. Results show three separated groups. Group I shows the best performance in terms of siloxane removal. There is a direct and strong relation between active surface area and microporous volume with the adsorption capacity. This direct correlation is not verified for some elements such as Fe and S, while it is respected for Cu and K. Higher performance are registered for not all the commercial carbons. In fact, the physical structure and impregnating agents are crucial for the siloxane removal