Adsorption and Electrothermal Desorption of Volatile Organic Compounds and Siloxanes onto an Activated Carbon Fiber Cloth for Biogas Purification

Abstract

Although biogases mainly consist of a mixture of carbon dioxide and methane, traces of volatile organic compounds are present, and these undesirable compounds must be removed during the purification process. Adsorption onto an activated carbon fiber cloth (ACFC) was investigated and, in particular, the feasibility of electrothermal desorption. Five compounds were chosen, and their desorption was assessed by monitoring the electric resistance of the material as a function of the temperature. The results were confirmed by thermogravimetric analysis. Toluene, dichloromethane, and isopropanol were entirely desorbed at 420 K, whereas siloxane D4 and ethyl mercaptan (ethanethiol) were partially removed. These conclusions were confirmed by dynamic adsorption measurements. Cycles of adsorption followed by electrothermal desorption were first carried out for a single component (toluene). Although there was a loss of adsorption capacity between the first and second cycles, a steady performance was reached, shedding...