Adsorption and Desorption Experimental Study of Carbon Dioxide/Methane Mixture Gas on 13X-Type Molecular Sieves

Adsorption is an effective method for removing carbon dioxide (CO2) from natural gas. Herein, an adsorption/desorption experimental apparatus was designed and constructed to examine the performances and adsorption capacities of three typical 13X-type molecular sieves, 13X-PG, 13X-HP, and APG-II, for removing CO2 from a methane (CH4)/CO2 mixture. The effects of varying initial CO2 contents and adsorption pressures on the adsorption performance were investigated and discussed, and it was found that increasing the adsorption pressure could increase the adsorption capacity of the three molecular sieves. However, the breakthrough time for each molecular sieve was shortened at increased initial CO2 contents in the gas mixture. Moreover, the effects of varying the nitrogen-heating temperatures and flow rates on the desorption performance were investigated, and it was found that increasing the nitrogen-heating temperature and flow rate shortened the desorption times. Thus, a high nitrogen-heating temperature and a large nitrogen-flow rate are beneficial for improving the desorption performance of the molecular sieves.