Apparatus for the production of xylenes

Patent metadata

Field	Value
Publication number	US-9738573-B2
Application number	US-201615058474-A
Country	US
Kind code	B2
Filing date	Mar 2, 2016
Priority date	Jun 30, 2014
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

In a process for producing para-xylene, a feed stream comprising C 6+ aromatic hydrocarbons is separated into a toluene-containing stream, a C 8 aromatic hydrocarbon-containing stream and a C 9+ aromatic hydrocarbon-containing stream. The toluene-containing stream is contacted with a methylating agent to convert toluene to xylenes and produce a methylated effluent stream. Para-xylene is recovered from the C 8 aromatic hydrocarbon-containing stream and the methylated effluent stream in a para-xylene recovery section to produce a para-xylene depleted stream, which is then contacted with a xylene isomerization catalyst under liquid phase conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream. The C 9+ -containing stream with a transalkylation catalyst under conditions effective to convert C 9+ -aromatics to C 8− -aromatics and produce a transalkylated stream, which is recycled together with the isomerized stream to the para-xylene recovery section.

First claim

The invention claimed is:

1. Apparatus for producing para-xylene, the apparatus comprising:
(a) a catalytic reformer for producing a reformate stream comprising C 6+ aromatic hydrocarbons;
(b) a first separation system for separating the reformate stream into at least a toluene-containing stream, a C 8 aromatic hydrocarbon-containing stream and a C 9+ aromatic hydrocarbon-containing stream;
(c) a toluene methylation unit for converting toluene in the toluene-containing stream to xylenes and produce a methylated effluent stream;
(d) a transalkylation unit for converting C 9+ aromatics in the C 9+ aromatic hydrocarbon-containing stream to C 8− aromatics and produce a transalkylation effluent stream;
(e) a second separation system for recovering para-xylene from the C 8 aromatic hydrocarbon-containing stream, the methylated effluent stream and the transalkylation effluent stream to produce at least one para-xylene depleted stream;
(f) a liquid phase xylene isomerization unit for isomerizing xylenes in the at least one para-xylene depleted stream to produce a first isomerized stream;
(g) a first recycle system for recycling at least part of the first isomerized stream to the second separation system; and
(h) a second recycle system for recycling at least part of the transalkylation effluent stream to the toluene methylation unit and second separation system.

2. The apparatus of claim 1 and further comprising:
(i) a vapor phase xylene isomerization unit for isomerizing xylenes in the at least one para-xylene depleted stream to produce a second isomerized stream; and
(j) a third recycle system for recycling at least part of the second isomerized stream to the second separation system.

3. The apparatus of claim 1 and further comprising:
(k) a third separation system for recovering ortho-xylene from one or more of the C 8 aromatic hydrocarbon-containing stream, the methylated effluent stream and a transalkylation effluent stream.

4. The apparatus of claim 1 and further comprising:
(l) an extraction system between the first separation system and toluene methylation unit for removing non-aromatics from the toluene-containing stream and produce a toluene-containing aromatic stream; and
(m) a fourth separation system for separating the toluene-containing aromatic stream into a benzene stream and a toluene stream, wherein the toluene stream is supplied to the toluene methylation unit.

5. The apparatus of claim 1 and further comprising:
(n) a fifth separation system for recovering unconverted toluene from the methylated effluent stream; and
(o) a fourth recycle system for recycling at least part of the unconverted toluene to the toluene methylation unit.

6. The apparatus of claim 1 wherein the first separation system comprises a dividing wall column.

7. The apparatus of claim 1 wherein second separation system comprises an adsorption process.

8. The apparatus of claim 1 wherein second separation system comprises a crystallization process.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Molinier Michel
• Abichandani Jeevan S
• Andrews Jeffrey L
• Tinger Robert G
• Stanley Dennis J
• Wagner George J

Classifications

• C07C7/13

  by molecular-sieve technique · CPC title

• B01J19/24

  Stationary reactors without moving elements inside (B01J19/08, B01J19/26 take precedence; with stationary particles B01J8/02) · CPC title

• C07C7/04

  by distillation · CPC title

• C07C15/08

  Xylenes · CPC title

• C07C6/123

  of only one hydrocarbon · CPC title