Abstract:
The UOP Parex process was the first commercial process. It is a continuous
process using a fixed bed of adsorbent. All process streams are in the
liquid phase at constant temperature in the bed. Feed is introduced and
p-xylene is se 1ect i ve 1y adsorbed. The adsorbed p-xylene is recovered from
the pores of the adsorbent by displacement with another liquid hydrocarbon.
The stream leaves the adsorbent bed with both the p-xylene product and the
rejected raffinate streams The desorbent is recovered from these two
streams by fractionation and is recycled to the adsorbent bed. A rotary
valve is employed in the process to stimulate countercurrent flow of solid
and liquid without actual movement of the solid adsorbent.
