US 9,517,979 B2Granted

Process and apparatus for the production of para-xylene

AssigneeExxonMobil Chemical Patents Inc.

InventorsTimothy P. Bender, John R. Porter, Dana L. Pilliod

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Abstract

A process for producing para-xylene (PX) comprises supplying a hydrocarbon feed comprising xylenes and ethylbenzene (EB) to a PX recovery unit, where a PX-rich stream and at least one PX-depleted stream are recovered from the feed. The PX-depleted stream is then separated into an EB-rich stream and an EB-depleted stream in a divided wall column. The EB-depleted stream is then isomerized under at least partial liquid phase conditions to produce a first isomerized stream having a higher PX concentration than the PX-depleted stream, and the EB-rich stream is isomerized under at least partial vapor phase conditions to produce a second isomerized stream having a higher PX concentration than the PX-depleted stream. The first and second isomerized streams are then recycled to the PX recovery unit to recover additional PX and the process is repeated to define a so-called xylene isomerization loop.

Claims19

Dependent claims

A process for producing para-xylene, the process comprising:

(a) providing a hydrocarbon feed comprising para-xylene, meta-xylene, ortho-xylene, and ethylbenzene to a para-xylene recovery unit;
(b) recovering a para-xylene-rich stream and at least one para-xylene-depleted stream from the hydrocarbon feed in the para-xylene recovery unit;
(c) separating the at least one para-xylene-depleted stream into an ethylbenzene-rich stream, which contains a majority portion of the ethylbenzene from the at least one para-xylene-depleted stream, and an ethylbenzene-depleted stream, which contains a minor portion of the ethylbenzene from the at least one para-xylene-depleted stream, in a divided wall column;
(d) isomerizing at least a portion of the ethylbenzene-depleted stream at least partially in the liquid phase back towards an equilibrium concentration of the xylenes isomers to produce a first isomerized stream having a higher para-xylene concentration than the para-xylene-depleted stream;
(e) isomerizing meta-xylene, ortho-xylene, and ethylbenzene in at least a portion of the ethylbenzene-rich stream at least partially in the vapor phase back towards to an equilibrium concentration of xylene isomers to produce a second isomerized stream having a higher para-xylene concentration than the para-xylene-depleted stream;
and
(f) recycling at least a portion of the first and second isomerized streams to the para-xylene recovery unit.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/969,298Filed 15 Dec 2015 · us provisional application
Priority: 19 Mar 2015
Published: US 2016/0272558 A122 Sep 2016
Granted: 13 Dec 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

C07C 5/2729
Rearrangement of carbon atoms in the hydrocarbon skeleton: changing the branching point of an open chain or the point of substitution on a ring
B01D 15/185
Simulated moving beds: characterised by the components to be separated
B01J 19/2445
Stationary reactors without moving elements inside: placed in parallel
C07C 5/2737
Catalytic processes: with crystalline alumino-silicates, e.g. molecular sieves

Family

Application62/135,255Us provisional application · filed 19 Mar 2015
US 2016/0272558 A1Pre-grant publication · published 22 Sep 2016
US 9,517,979 B2This patent

From the US filing history. Foreign family members aren’t listed.

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