Selection and modification of adsorbent for separation of coal mine gas by PSA process

Series of studies of adsorbent in the enrichment and separation of coal mine gas were carried out, five kinds of ACFs were chosen and their BET surface area and adsorption isotherms of CH ₄ and N ₂ at 298 K were measured. By comparing adsorption capacities and separation factors, an optimal adsorbent chosen and modified with ammonia to explore the best modification conditions. Results show that ZC1 is the best adsorbent. It is shown that, in comparison with the original ACF, the modified ACFs have larger pore volume and larger surface area, so that their adsorption capacities of CH ₄ and N ₂ are the highest. The ACF modified with 5 mol/L ammonia aqueous solution is the best one and its separation factor reaches 5.32.