Process for recovering benzene and fuel gas in an aromatics complex

Patent metadata

Field	Value
Publication number	US-10793493-B2
Application number	US-201715692555-A
Country	US
Kind code	B2
Filing date	Aug 31, 2017
Priority date	Aug 31, 2017
Publication date	Oct 6, 2020
Grant date	Oct 6, 2020

Abstract

A process for separating xylenes from a feedstock in which the feedstock is separated into a xylene stream, a benzene rich stream and a light ends stream. Two separation zones may be utilized in which liquid from the first zone sent to a toluene recovery zone and vapor from the first zone is sent to a compression zone. The compressed vapor from the compression zone is sent to the second separation zone.

First claim

The invention claimed is:

1. A process for the recovery of a benzene rich liquid stream and a light ends vapor stream in a xylene isomerization process from a feedstock, the process comprising:
passing a feedstock into a deheptanizer in which the feedstock is separated into a deheptanizer vapor phase and a deheptanizer liquid phase, the deheptanizer vapor phase containing hydrocarbons with seven carbon atoms or less, and the deheptanizer liquid phase containing hydrocarbons with eight carbon atoms or more;
passing the deheptanizer vapor phase from the deheptanizer to a first separation zone;
separating the deheptanizer vapor phase in the first separation zone into a first liquid phase and a first vapor phase;
passing the first liquid phase from the first separation zone to a toluene recovery zone, the toluene recovery zone comprising a vessel configured to provide an overhead stream and a bottoms stream;
passing the first vapor phase from the first separation zone to a compression zone in which the first vapor phase is compressed and partially condensed to provide a compressed and partially condensed vapor phase;
combining the compressed and partially condensed vapor phase from the compression zone with the toluene recovery zone overhead stream;
separating the compressed and partially condensed vapor phase and the toluene recovery zone overhead stream into a second liquid phase and a second vapor phase in a second separation zone, the second vapor phase being a light ends vapor stream;
recovering the light ends vapor stream;
passing a portion of the second liquid phase back to the toluene recovery zone; and
recovering a toluene rich liquid stream from the toluene recovery zone, wherein the toluene recovery zone comprises a stripper column; and
recovering the benzene rich liquid stream from the second liquid phase.

2. The process of claim 1 further comprising passing a portion of the first liquid phase to the deheptanizer.

3. The process of claim 1 further comprising passing the benzene rich liquid stream to an extraction zone to recover a benzene stream.

4. The process of claim 1 further comprising passing the benzene rich liquid stream to storage.

5. The process of claim 1 further comprising compressing the deheptanizer vapor stream before the deheptanizer vapor stream enters the first separation zone.

6. The process of claim 5 wherein a temperature of the first separation zone is between approximately 32° C. to 149° C.

7. The process of claim 6 wherein a temperature of the second separation zone is between approximately 10° C. to 149° C.

8. The process of claim 1 wherein a temperature of the first separation zone is between approximately 10° C. to 149° C. and a temperature of the second separation zone is between approximately 10° C. to 149° C.

9. A process for the recovery of a benzene rich liquid stream and a light ends vapor stream in a xylene isomerization process from a feedstock, the process comprising:
passing a feedstock into a distillation column in which the feedstock is separated into a distillation vapor and a distillation liquid, the distillation vapor containing mostly hydrocarbons with seven carbon atoms or less;
condensing the distillation vapor;
separating the distillation vapor into a first liquid phase and a first vapor phase; passing the first liquid phase to a toluene recovery zone, wherein the toluene recovery zone comprises a stripper column;
compressing the first vapor phase into a compressed and partially condensed vapor phase;
separating the compressed vapor phase into a second liquid phase and a second vapor phase, the second vapor phase being a light ends vapor stream;
recovering the light ends vapor stream;
passing the second liquid phase to the toluene recovery zone; and
recovering a toluene rich liquid stream from the toluene recovery zone; and
recovering the benzene rich liquid stream from the second liquid phase.

10. The process of claim 9 wherein a temperature of the first liquid phase is between approximately 32° C. to 149° C.

11. The process of claim 10 wherein a temperature of the compressed vapor phase is between approximately 10° C. to 149° C.

12. The process of claim 9 further comprising passing a portion of the first liquid phase to the distillation column.

13. The process of claim 9 further comprising passing the benzene rich liquid stream to an extraction zone to recover a benzene stream.

14. The process of claim 9 further comprising passing the benzene rich liquid stream to storage.

15. A process for the recovery of a benzene rich liquid stream and a light ends vapor stream in a xylene isomerization process from a feedstock, the process comprising:
passing a feedstock into a separation zone in which the feedstock is separated into a vapor stream and a liquid stream, the vapor stream containing mostly hydrocarbons with seven carbon atoms or less, the liquid stream comprising xylene;
condensing the vapor stream;
separating the vapor stream into a first liquid phase and a first vapor phase;
passing the first vapor phase to a compression zone;
compressing the first vapor phase into a compressed and partially condensed vapor phase;
separating the compressed vapor phase into a second liquid phase and a second vapor phase, the second vapor phase being a light ends vapor stream;
recovering the light ends vapor stream; and
recovering a toluene rich liquid stream from a toluene recovery zone, wherein the toluene recovery zone comprises a stripper column; and
recovering the benzene rich liquid stream from the second liquid phase.

16. The process of claim 15 wherein a temperature of the first liquid phase is between approximately 32° C. to 149° C.

17. The process of claim 15 wherein a temperature of the compressed vapor phase is between approximately 10° C. to 149° C.

18. The process of claim 1 , further comprising:
recovering a first portion of the second liquid phase from the second separation zone; and,
passing a second portion of the second liquid phase from the second separation zone to the toluene recovery zone.

Assignees

• Uop Llc

Inventors

• Corradi Jason T
• Miller Ryan D

Classifications

• B01D3/10

  Vacuum distillation (B01D3/12 takes precedence) · CPC title

• B01D3/106

  with the use of a pump for creating vacuum and for removing the distillate · CPC title

• C07C5/2702

  Catalytic processes not covered by C07C5/2732 - C07C5/31; Catalytic processes covered by both C07C5/2732 and C07C5/277 simultaneously · CPC title

• C07C7/09

  by fractional condensation · CPC title

• C07C15/06

  Toluene · CPC title