| abstract |
A pressure swing adsorption (PSA) process to separate para-xylene and ethylbenzene from C8 aromatics which uses a para-selective, non-acidic, medium pore molecular sieve of the MFI structure type and is operated isothermally in the vapor phase at elevated temperatures and pressures is disclosed. A fixed bed of adsorbent is saturated with pX and EB, which are preferentially adsorbed, the feed is stopped, and lowering the partial pressure desorbs the pX and EB. The process effluent, which is rich in pX and EB, may be purified by crystallization or simulated moving bed adsorption to obtain para-xylene product. The C8 aromatics stream used in the PSA process may be obtained from a refinery feed or from the conversion of toluene. |