Multi-step biogas quality improving by adsorptive packed column system as application to biomethane upgrading

This study investigates the effect of the specially designed adsorptive packed column system (APCS) in improving the quality of biogas to biomethane purity. The APCS installed with the specially constructed "dispersal star" was operated on biogas from wastewater treatment plant. The four adsorbent packed columns were arranged based on two impregnated and two no-impregnated commercially available active carbons to remove siloxanes, halogenated compounds and volatile organic compounds. The removal performance of ACPS was tested using portable devices along with gas chromatography techniques coupled with different types of detectors. The removal efficiency of total non-silica impurities was obtained at the level of 99.76%, whereas siloxanes were removed entirely. The adsorption affinity of siloxanes in the shape of D4 and D5 was considered by adsorption on high BET surface area adsorbent, while the desulphurisation process was conducted on impregnated active carbons. This study describes the concentrations of silica and non-silica impurities in relation to CHP manufacturers' limits and biomethane quality. Furthermore, the economical estimation of full-scale APCS was also conducted taking into account the three variants of biogas purity, as well as different types of iron-based adsorbents.