Flushing Flow Rates Analysis in Eight-Zone SMB Process for p-Xylene Separation

摘要

The eight zone p-xylene (PX) simulated moving bed (SMB) utilizes three flushingrnsequences to prevent purity and recovery deterioration caused by transfer lines (or bedlines)rnconnecting rotary valve to adsorption beds. The application of flushing sequencesrnmakes the analysis and operation of this process more difficult and they rely onrnoperation experience. In this study, effects of the flushing flow rates on SMBrnperformance were investigated by sensitivity analysis at various axial dispersionrnintensities of dead volume. The concentration dynamics inside dead volume were solvedrnby the method of characteristic (MOC). This study indicates that the flushing flow ratesrnmust be tuned properly in order to maximize PX recovery within desired purity.