Fractionation of gas mixtures in a moving-bed adsorber. I. Correlation of adsorber performance



The design and operation of a pilot-scale-moving bed adsorber to separate the various components of a gas mixture using activated carbon as the preferential adsorbent are described. A binary system, methane–acetylene, and a ternary system, methane–carbon dioxide–acetylene, were studied. The performance of the unit was analyzed by means of the transfer-unit-height (H.T.U.) concept based on the observed changes in gas composition during tower operation. For both the binary and ternary systems the transfer-unit height was independent of feed-gas composition but was found to vary linearly with the ratio of feed gas to carbon flow. The over-all transfer-unit-height values based on either the gas or the adsorbed phase were observed to vary from 6.5 in. at 1.39 std. cu. ft./lb. carbon to 36.9 in. at 4.81 std. cu. ft./lb. carbon.