Systems and methods for separating xylene isomers using selective adsorption

Patent metadata

Field	Value
Publication number	US-9302955-B2
Application number	US-201314040363-A
Country	US
Kind code	B2
Filing date	Sep 27, 2013
Priority date	Sep 27, 2013
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

Methods and systems are provided for separating a selected xylene isomer. The method includes separating a feed stream including a plurality of aromatic hydrocarbons into a first stream including toluene and isomers of xylene, and a second stream including isomers of xylene. The method further includes separating the first stream into a third stream including toluene and a fourth stream including isomers of xylene. The method further includes combining the second stream and the third stream in an adsorptive separation unit including an adsorbent configured to adsorb the selected xylene isomer from the second stream. The third stream desorbs the selected xylene isomer to produce a fifth stream including the selected xylene isomer and toluene and a sixth stream including non-selected xylene isomers and toluene. Still further, the method includes separating the sixth stream into a seventh stream including the non-selected xylene isomers and the third stream including toluene.

First claim

The invention claimed is:

1. A method for separating a selected xylene isomer comprising the steps of:
separating a feed stream comprising a plurality of aromatic hydrocarbons into a first stream comprising toluene and isomers of xylene, and a second stream comprising isomers of xylene;
separating, in a first zone of a multi-zone separation apparatus, the first stream into a third stream comprising toluene and a fourth stream comprising isomers of xylene;
combining the second stream and the third stream in an adsorptive separation unit comprising an adsorbent configured to adsorb the selected xylene isomer from the second stream, wherein the third stream desorbs the selected xylene isomer from the adsorbent to produce a fifth stream comprising the selected xylene isomer and toluene and a sixth stream comprising non-selected xylene isomers and toluene; and
separating, in a second zone of the multi-zone separation apparatus, the sixth stream into a seventh stream comprising the non-selected xylene isomers and the third stream comprising toluene.

2. The method of claim 1 , wherein separating the feed stream comprises separating a reformed naphtha stream.

3. The method of claim 1 , wherein separating the feed stream into the first stream and the second stream comprises performing a first separation process in a splitter distillation column to form an overhead product and a bottom product therefrom, and performing a second separation process in a stripper distillation column comprising a stabilizer column integrated into the stripper distillation column, wherein performing the second separation process comprises producing a stabilizer product from the stabilizer and a side-draw product from the stripper distillation column, wherein the stabilizer product and the overhead product are combined to form the first stream and the side-draw product form the second stream.

4. The method of claim 1 , wherein separating the feed stream further comprises forming an eighth stream comprising C9+ hydrocarbons.

5. The method of claim 4 , further comprising transalkylating the eighth stream to form a stream comprising additional isomers of xylene.

6. The method of claim 5 , wherein transalkylating the eighth stream comprises combining the eighth stream with a portion of the third stream in a transalkylation reactor.

7. The method of claim 6 , further comprising combining the stream comprising additional isomers with the second stream.

8. The method of claim 1 , further comprising isomerizing the seventh stream comprising the non-selected xylene isomers to form a ninth stream comprising both the selected xylene isomer and the non-selected xylene isomers.

9. The method of claim 8 , further comprising combining the ninth stream with the second stream.

10. The method of claim 1 , wherein adsorbing the selected xylene isomer comprises adsorbing para-xylene.

11. The method of claim 1 , wherein adsorbing the selected xylene isomer comprises adsorbing para-xylene.

12. A method for separating a selected xylene isomer comprising the steps of:
separating a feed stream comprising a plurality of aromatic hydrocarbons into a first stream comprising toluene and isomers of xylene, and a second stream comprising isomers of xylene, wherein separating the feed stream into the first stream and the second stream comprises performing a first separation process in a splitter distillation column to form an overhead product and a bottom product therefrom, and performing a second separation process in a stripper distillation column comprising a stabilizer column integrated into the stripper distillation column, wherein performing the second separation process comprises producing a stabilizer product from the stabilizer and a side-draw product from the stripper distillation column, wherein the stabilizer product and the overhead product are combined to form the first stream and the side-draw product form the second stream;
separating, in a first zone of a multi-zone separation apparatus, the first stream into a third stream comprising toluene and a fourth stream comprising isomers of xylene;
combining the second stream and the third stream in an adsorptive separation unit comprising an adsorbent configured to adsorb the selected xylene isomer from the second stream, wherein the third stream desorbs the selected xylene isomer from the adsorbent to produce a fifth stream comprising the selected xylene isomer and toluene and a sixth stream comprising non-selected xylene isomers and toluene;
separating, in a second zone of the multi-zone separation apparatus, the sixth stream into a seventh stream comprising the non-selected xylene isomers and the third stream comprising toluene; and
isomerizing the seventh stream comprising the non-selected xylene isomers to form an eighth stream comprising both the selected xylene isomer and the non-selected xylene isomers.

Assignees

• Uop Llc

Inventors

• Corradi Jason T
• Werba Gregory
• Gattupalli Rajeswar

Classifications

• C07C7/005 Primary

  Processes comprising at least two steps in series · CPC title

• C07C6/126

  of more than one hydrocarbon · CPC title

• B01D15/10

  characterised by constructional or operational features · CPC title

• B01D3/143

  by two or more of a fractionation, separation or rectification step · CPC title

• C07C7/13

  by molecular-sieve technique · CPC title