Producing C6-C8 aromatics from FCC heavy naphtha

Patent metadata

Field	Value
Publication number	US-11028329-B1
Application number	US-202016845549-A
Country	US
Kind code	B1
Filing date	Apr 10, 2020
Priority date	Apr 10, 2020
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A method of forming C6-C8 aromatics may include selectively dealkylating a Fluid Catalytic Cracking (FCC) heavy cut naphtha that has at least C9+ aromatics to selectively crack C2+ alkyl chains from the C9+ aromatics, thereby forming the C6-C8 aromatics. The selectively de-alkylated heavy cut naphtha is then combined with a FCC middle cut naphtha, and aromatics including the C6-C8 aromatics are separated from the combined stream. A system for forming C6-C8 aromatics may include a fluid catalytic cracking unit for producing a FCC heavy cut naphtha comprising at least C9+ aromatics; a de-alkylation reactor for selectively cracking C2+ alkyl chains from the C9+ aromatics, thereby forming the C6-C8 aromatics; and an aromatic extraction unit for extracting at least a portion of the C6-C8 aromatics.

First claim

What is claimed is:

1. A method of forming C 6 -C 8 aromatics, comprising:
selectively de-alkylating a Fluid Catalytic Cracking (FCC) heavy cut naphtha (HCN),
wherein at least 90 vol % of the FCC HCN is C 9 +,
wherein the FCC HCN comprises at least C 9+ aromatics, to selectively crack C 2+ alkyl chains from the C 9+ aromatics, thereby forming the C 6 -C 8 aromatics;

combining the selectively de-alkylated heavy cut naphtha with a FCC middle cut naphtha (MCN); and
separating aromatics including the C 6 -C 8 aromatics from the combined stream.

2. The method of claim 1 , further comprising:
trans-alkylating separated aromatics.

3. The method according to claim 1 , sending a raffinate remaining after separating the aromatics from the combined stream to a gasoline pool.

4. The method according to claim 1 , wherein reforming a raffinate remaining after separating the aromatics from the combined stream.

5. The method according to claim 1 , further comprising: combining a light portion of a FCC light cycle oil with the FCC heavy cut naphtha prior to the selective de-alkylation.

6. The method according to claim 5 , wherein the FCC light cycle oil comprises C 10+ aromatics, C 10+ olefins, C 10+ paraffins, and C 10+ naphthenes.

7. The method of claim 1 , wherein the FCC heavy cut naphtha comprises C 9+ olefins, C 9+ paraffins, C 9+ naphthenes, and C 9+ aromatics.

8. The method according to claim 1 , wherein the FCC heavy cut naphtha has an initial cut above 100° C. and an end cut below 240° C.

9. The method according to claim 1 , wherein the FCC heavy cut naphtha has an initial cut above 140° C. and an end cut below 180° C.

10. The method of claim 1 , wherein the de-alkylation is performed at a temperature ranging from 200-540° C., a pressure ranging from 10-50 bar, a liquid hourly space velocity ranging from 1-20 h −1 , and a hydrogen to feed ratio ranging from 0-20.

11. A system for forming C 6 -C 8 aromatics, comprising:
a fluid catalytic cracking (FCC) unit for producing a FCC heavy cut naphtha (HCN) comprising at least C 9+ aromatics, wherein at least 90 vol % of the FCC HCN is C 9+ ;
a de-alkylation reactor configured to receive the at least 90 vol % FCC HCN that is C 9+ for selectively cracking C 2+ alkyl chains from the C 9+ aromatics, thereby forming the C 6 -C 8 aromatics; and
an aromatic extraction unit configured to receive the C 6 -C 8 aromatics for extracting at least a portion of the C 6 -C 8 aromatics.

12. The system according to claim 11 , further comprising a trans-alkylation unit for converting meta-xylene and ortho-xylene into para-xylene.

13. The system of claim 12 , wherein the trans-alkylation unit receives aromatics from the aromatics extraction unit.

14. The system according to claim 11 , wherein the aromatic extraction unit also receives an FCC middle cut naphtha feed from the fluid catalytic cracking unit.

15. The system according to claim 11 , wherein the FCC heavy cut naphtha comprises 0-10 vol. % paraffin, 0-10 vol. % naphthenes, 0-30 vol. % olefins, and 50-90 vol. % aromatics.

16. The system according to claim 11 , wherein the C 9+ aromatics in the FCC heavy cut naphtha comprises 20-75 wt % C 9 aromatics, 20-75 wt % C 10 aromatics and 5-20 wt % C 11 aromatics.

17. The system according to claim 11 , wherein the selective de-alkylation reactor also receives an FCC light cut oil.

18. The system according to claim 11 , wherein the FCC light cycle oil comprises 0-10 vol. % paraffin, 0-10 vol. % naphthenes, 0-20 vol. % olefins, and 60-95 vol. % aromatics.

19. The system according to claim 18 , wherein the aromatics in the FCC light cycle oil comprise 0-5 wt % C 9 aromatics, 0-10 wt % C 10 aromatics, 0-30 wt % C 11 aromatics, 0-30 wt % C 12 aromatics, 0-30 wt % C 13 aromatics, and 0-20 wt % C 14+ aromatics.

Assignees

• Saudi Arabian Oil Co

Inventors

• He Yufeng
• Al Ghazal Abdullah
• Xu Qi

Classifications

• B01J2219/0004

  Processes in series · CPC title

• C10G21/02

  with two or more solvents, which are introduced or withdrawn separately · CPC title

• B01J19/245

  placed in series · CPC title

• C10G61/02

  plural serial stages only · CPC title

• C10G55/06 Primary

  including at least one catalytic cracking step · CPC title