The experiment study on ventilation air methane enrichment by vacuum pressure swing adsorption

In order to recovery and utilization of vast ventilation air methane (VAM) released into the atmosphere, the vacuum pressure swing adsorption process was employed to enrich the VAM. In this paper, the adsorption characteristics of activated carbon for VAM enrichment had been tested. Then two absorbers of vacuum pressure swing adsorption unit was setup. The VAM with methane concentration of 0.3% was enriched experimentally. The result shows that the VAM can enrich to 0.73% with the adsorption pressure no more than 250 kPa abs., and desorption pressure about 25 kPa abs.; pressure equalization is helpful to improve the methane concentration, especially when pressure equalization at both ends of the absorber; increase the adsorption pressure is useful to raise the product's methane concentration, the adsorption pressure increased from 150 kPa to 250 kPa, the methane concentration of product increased from 0.56% to 0.73%; decrease the desorption pressure decrease the product's methane concentration significantly. This study provides a theoretical foundation in industrial applications for the VAM recovery and utilization.