SILOXANES REMOVAL FROM BIOGAS USING ACTIVATED CARBON

Abstract

SiO2 deposits which cause technical problems on combustion equipment are built by combustion of biogas containing siloxanes. Therefore, in these cases, the siloxanes must be removed from the biogas. For siloxane removal from biogas, its adsorption on activated carbon is often used. After saturation, the saturated adsorbent must be replaced. The adsorbent cost constitutes the main part of the operational costs of the purification equipment. Therefore it is necessary to find an adsorbent having high adsorption capacity for siloxane at a possible low price. Using laboratory apparatus and biogas produced from waste-water treatment sludge at the wastewater treatment plant Prague Bubenec various activated carbons were tested for siloxane removal and their adsorption capacities for siloxanes were estimated, and the adsorbent cost relative to 1 kg of siloxanes removed from biogas were calculated. The lowest price for the removal of 1 kg of siloxanes was determined by Chezacarb, Sil Extra 40 AP and 4–60 adsorbents. Another important information obtained from the test is that the weakly adsorbed siloxane (OMCTS) is displaced by the larger molecule of DMCPCS during adsorption.