Performance Analysis of Commercial and Innovative Materials aiming for Deep Biogas Cleaning

In the current challenge to contain the global warming, renewable energy sources development plays a crucial role to decarbonise the energy sector. In this context, biogas have the potential to act as a renewable energy and carbon source for energy production and chemical industry applications. Biogas production from anaerobic digestion of organic wastes sets allows this renewable energy production in the circular economy frame. Therefore, several EU projects have been and are still conducted. The Waste2Watt project aims at designing flexible cleaning systems to unlock the potentialities of a biogas for CHP production through Fuel Cells. Its focuses are both on small scale applications (e.g. zootechnic effluents from farms), for which the cleaning technology is adsorption-based, and large scale applications (e.g. OFMSW use via an efficient municipal waste management), for which the cleaning technology is cryogenic separation. The role of Politecnico di Torino, PSI Institute and ENEA Institute is to support the design of optimized absorption-based cleaning systems through commercial and innovative sorbent-materials testing. The final decision for an optimized cleaning system will merge the information about the tested materials performances, with the purchase and waste management costs in a techno-economical analysis. Commercially available and new-on-market materials have been selected by contacting the suppliers directly, while the main biogas pollutants have been shared among the project partners, specifically, Politecnico di Torino tested H2S and will test CH4S. Tests have been conducted by simulating a realistic biogas composition (CO2, CH4, O2, humidity and the pollutant). A particular interest have been used in analysing the performances in presence of oxygen and humidity due to the possibility of various sorbents to perform chemisorption, so to capture the pollutant not only through weak Van der Waals forces, but by converting it into other chemicals. For this reason, sorbent materials have been analysed to evaluate both the specific surface area (BET analysis) and their composition (XRD analysis). The latter was specifically oriented towards analysing the presence and the effect of active sites. Test results, combined with fresh and exhausted material analysis, allow to analyse the adsorption process and to evaluate the sorbets performances. Secondly, multipollutant streams will be tested as well, to analyse the sorbents behaviour in more realistic working conditions.