(338g) Solvent Recovery by Dual Reflux PSA Simulation,Examination of Cycle Time

Pressure swing adsorption (PSA) method is a cyclic process useful for the separation of gaseous mixtures. Though there were some problems to be solved, there may be some possibility to apply PSA to solvent recovery. Dual reflux PSA is a new pressure swing adsorption process proposed for treatment of low-VOC-concentration air streams. Feed gas is supplied to the high pressure column at some intermediate position to divide it into an enriching and a stripping sections. A part of air stream leaving the high pressure column is returned to the low pressure column as enriching reflux. And we can get VOC as a liquid by dual reflux PSA process. In this study, the solvent recovery by dual reflux PSA with silica gel was tested by process simulation. As a first step, CH2Cl2 was chosen as solvent. Numerical calculation for dual reflux PSA was tried using Stop & Go method. Performances were compared as for amount of solvent recovery for different type of sequence time. Operation sequence was consisted of four sequence, pressurization step, adsorption step, evacuation step and purge step. We studied six type cycle time in a constant column. Therefore, cycle time was thought as important condition in optimization.