Design and operation of an industrial size adsorption-based cleaning system for biogas use in fuel cells

The use of biogas, one of the main players in the energy transition, requires the efficient removal of harmful traces of impurities. Reliable and robust purification systems are therefore required before the biogas is fed into cogeneration or upgrading plants. In this work, an industrial-scale biogas purification system for the deep removal of impurities is analysed. The experimental design phase in the laboratory and the subsequent evaluation of the system's performance in the field, are presented. The work was carried out as part of the DEMOSOFC project, where the first industrial-scale SOFC system was operated in a real wastewater treatment plant fed with sewage gas. The system is an adsorption-based plant that uses multiple sorbents. The on-site operation lasted more than 15,000 h and was used to analyse the performance with real sewage biogas. A continuous and innovative online gas analyser was also installed, and its measurements were verified with analyses from an external laboratory. The performance of the sorbents met the expectations measured in the laboratory. The loading rate – measured in % of the maximum loading rate of the sorbents – was 35% for H2S and 1.8% for siloxanes, confirming the optimal design of the purification unit.