The Petlyuk PSA process for the separation of ternary gas mixtures: exemplification by separating a mixture of CO2–CH4–N2

Abstract

The Petlyuk PSA process, proposed for the separation of ternary gas mixtures, consists of two pairs of adsorption columns, intermediate feed inlet and side stream outlet. An experimental study, involving the separation of a ternary gas mixture containing carbon dioxide, methane and nitrogen, was conducted to testify to its feasibility and investigate its performance by utilizing three kinds of adsorbent of activated carbon, zeolite 13X, and carbon molecular sieve. The results demonstrated that CO2, CH4 and N2 could apparently be enriched in the top, side and bottom product streams, respectively. Under the operating conditions, with the feed containing CO2 and CH4 both over 12%, CO2 could be enriched up to 60% in the top product, CH4 could be enriched above 60% in the side product, and N2 could be concentrated to higher than 95% in the bottom product. It could be concluded that the Petlyuk PSA process is feasible to separate ternary gas mixtures, and the operating parameters such as reflux ratios, half cycle time, etc. have apparent effects on its performance.