DESIGN AND PERFORMANCE OF A SIMULATED COUNTERCURRENT MOVING-BED SEPARATOR

The design, construction and isothermal (298 K) operation of a continuous flow simulated countercurrent moving-bed chromatographic separator for the gas-solid separation of binary mixtures is reported. It consists of only four packed columns, with countercurrency simulated by advancing the feedpoint from column to column in the direction of gas flow. The separated components have periodic concentration profiles, with a duty cycle that depends on operating parameters, and concentrations greater than in the feed stream. Test mixtures of propylene and dimethyl ether, which have retention times differing by a factor of 2 on the 60180 mesh Chromosorb 101 packing, were successfully separated. Optimum feed advancement intervals and maximum product purity were experimentally determined as a function of feed rate. At low feed rates, when the adsorption isotherm is nearly linear, dimethyl ether was nearly completely separated from propylene, but propylene was found to contain varying amounts of dimethyl ether due to the effects of a nonlinear isotherm and heterogeneous adsorption.