A Novel VPSA Process for Ventilation Air Methane Enrichment by Active Carbon

Enrichment of ventilation air methane (VAM) is crucial to gather acceptable concentration to utilize. In this work, the adsorption characteristics of activated carbon have been tested. A novel three-bed VPSA cycle for recovering methane from methane/nitrogen mixtures using activated carbon have been done experimentally, and the VPSA process studied contains an effluent pressurization step to improve product concentration and recovery. The VPSA process was carried out under adsorption pressure at 155 kPa abs., and desorption pressure at 20 kPa abs., feeding VAM with the methane purity of 0.2%, methane purity of 0.4% with 70% recovery was obtained at ambient temperature while 0.36% purity with 87% recovery. This process has the potential of significantly increasing the product concentration and recovery with respect to the two-bed cycle process by VPSA.