Transalkylation processes for converting aromatic hydrocarbons comprising alkyl-demethylation

Patent metadata

Field	Value
Publication number	US-10975005-B2
Application number	US-202016903058-A
Country	US
Kind code	B2
Filing date	Jun 16, 2020
Priority date	Jul 19, 2019
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

Alkyl-demethylation of C2+-hydrocarbyl substituted aromatic hydrocarbons can be utilized to treat one or more of a heavy naphtha reformate stream, a hydrotreated SCN stream, a C8 aromatic hydrocarbon isomerization feed stream, a C9+ aromatic hydrocarbon transalkylation feed stream, and similar hydrocarbon streams to produce additional quantity of xylene products.

First claim

What is claimed is:

1. A transalkylation process, the process comprising:
(A) providing a C9+ aromatic hydrocarbon stream comprising a C2+-hydrocarbyl-substituted aromatic hydrocarbon, wherein the C2+-hydrocarbyl-substituted aromatic hydrocarbon has (i) a C2+ alkyl substitute attached to an aromatic ring therein and/or (ii) an aliphatic ring annelated to an aromatic ring therein;
(B) optionally contacting at least a portion of the C9+ aromatic hydrocarbon stream with an alkyl-demethylation catalyst No. 1 in an alkyl-demethylation zone No. 1 under a set of alkyl-demethylation conditions No. 1 to convert at least a portion of the C2+-hydrocarbyl-substituted aromatic hydrocarbon contained in the C9+ aromatic hydrocarbon stream to an alkyl-demethylated hydrocarbon to produce an alkyl-demethylated effluent No. 1 exiting the alkyl-demethylation zone No. 1;
(C) optionally separating the C9+ aromatic hydrocarbons stream and/or the alkyl-demethylated effluent No. 1 in a separation device No. 1 to obtain a C9-C10 aromatic hydrocarbons-rich stream and a C11+ aromatic hydrocarbons-rich stream;
(D) optionally contacting at least a portion of the alkyl-demethylated effluent No. 1 and/or at least a portion of the C9-C10 aromatic hydrocarbons-rich stream with an alkyl-demethylation catalyst No. 2 in an alkyl-demethylation zone No. 2 under a set of alkyl-demethylation conditions No. 2 to convert at least a portion of the C2+-hydrocarbyl-substituted aromatic hydrocarbon, if any, contained in the alkyl-demethylated effluent No. 1 and/or the C9-C10 aromatic hydrocarbons-rich stream to an alkyl-demethylated hydrocarbon to produce an alkyl-demethylated effluent No. 2 exiting the alkyl-demethylation zone No. 2;
(E) feeding at least a portion of the C9+ aromatic hydrocarbons stream, and/or at least a portion of the alkyl-demethylated effluent No. 1, and/or at least a portion of the C9-C10 aromatic hydrocarbons-rich stream, and/or at least a portion of the alkyl-demethylated effluent No. 2, and an optional benzene/toluene stream to a transalkylation zone;
(F) contacting C9+ aromatic hydrocarbons with benzene/toluene in the presence of a transalkylation catalyst in the transalkylation zone under transalkylation conditions to produce a transalkylation effluent exiting the transalkylation zone; and
(G) separating the transalkylation effluent in a separation device No. 2 to obtain an optional benzene product stream, a toluene-rich stream, and a C8+ aromatic hydrocarbons-rich stream;
wherein at least one of steps (B) and (D) is carried out.

2. The transalkylation process of claim 1 , further comprising:
(H) separating at least a portion of the C8+ aromatic hydrocarbons-rich stream in a separation device No. 3 to obtain a xylenes-rich stream and a C9+ aromatic hydrocarbons-rich stream; and
(I) providing at least a portion of the C9+ aromatic hydrocarbons-rich stream as at least a portion of the C9+ aromatic hydrocarbon stream in step (A).

3. The transalkylation process of claim 1 , wherein step (B) is carried out.

4. The transalkylation process of claim 1 , wherein step (C) is carried out.

5. The transalkylation process of claim 3 , wherein step (C) is carried out, and the C9-C10 aromatic hydrocarbons-rich stream further comprises C7 and C8 aromatic hydrocarbons.

6. The process of claim 1 , further comprising:
(J) feeding at least a portion of the benzene product stream and/or at least a portion of the toluene-rich stream to the transalkylation zone as at least a portion of the benzene/toluene stream in step (E).

7. The process of claim 1 , wherein the alkyl-demethylation zone No. 2 is upstream of the transalkylation zone.

8. The process of claim 4 , further comprising:
(K) contacting at least a portion of the alkyl-demethylated effluent No. 2 and/or at least a portion of the C9-C10 aromatic hydrocarbons-rich stream with an alkyl-demethylation catalyst No. 3 in an alkyl-demethylation zone No. 3 under a set of alkyl-demethylation conditions No. 3 to convert at least a portion of the C2+-hydrocarbyl-substituted aromatic hydrocarbon, if any, contained in the alkyl-demethylated effluent No. 2 and/or the C9-C10 aromatic hydrocarbons-rich stream to an alkyl-demethylated hydrocarbon, wherein the alkyl-demethylation zone No. 3 at least partly overlaps with the transalkylation zone.

9. The process of claim 1 , wherein the alkyl-demethylation zone No. 2 at least partly overlaps with the transalkylation zone.

10. The process of claim 1 , wherein the first alkyl-demethylation catalyst, and/or the second alkyl-demethylation catalyst, and/or the third alkyl-demethylation catalyst, the same or different, comprise a first metal element selected from groups 7, 8, 9, and 10 metals and combinations thereof, and a support.

11. The process of claim 10 , wherein the first metal element is selected from Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and combinations thereof.

12. The process of claim 10 , wherein the concentration of the first metal element in the respective alkyl-demethylation catalyst is in a range from 0.1 to 10 wt %, based on the total weight of the respective alkyl-demethylation catalyst.

13. The process of claim 10 , wherein the first alkyl-demethylation catalyst, and/or the second alkyl-demethylation catalyst, and/or the third alkyl-demethylation catalyst, the same or different, further comprises a second metal element selected from groups 11, 12, 13, and 14 metals, and combinations thereof.

14. The process of claim 13 , wherein the second metal element is selected from Cu, Ag, Au, Zn, Al, Ga, Sn, and combinations thereof.

15. The process of claim 13 , wherein the concentration of the second metal element in the respective alkyl-demethylation catalyst is in a range from 0.1 to 10 wt %, based on the total weight of the respective alkyl-demethylation catalyst.

16. The process of claim 10 , wherein the first alkyl-demethylation catalyst and/or the second alkyl-demethylation catalyst, the same or different, further comprises a third metal element selected from groups 1 and 2 metals, and combinations thereof.

17. The process of claim 16 , wherein the third metal element is selected from Li, N, K, Rb, Cs, Mg, Ca, Ba, and combinations thereof.

18. The process of claim 16 , wherein the concentration of the third metal element in the respective alkyl-demethylation catalyst is in a range from 0.1 to 10 wt %, based on the total weight of the respective alkyl-demethylation catalyst.

19. The process of claim 10 , wherein the first alkyl-demethylation catalyst, and/or the second alkyl-demethylation catalyst, and/or the third alkyl-demethylation catalyst, the same or different, comprises a molecular sieve as at least a portion of the support.

20. The process of claim 1 , wherein the set of alkyl-demethylation conditions No. 1, the set of alkyl-demethylation conditions No. 2, and the set of alkyl-demethylation conditions No. 3, the same or different, comprise at least one of:
a temperature in a range from 200 to 500° C.;
an absolute pressure in a range from 350 to 2500 kilopascal;
a molar ratio of molecular hydrogen to hydrocarbon in a range from 0.5 to 20; and
a liquid weight hourly space velocity in a range from 1 to 20 hour −1 .

21. The process of claim 20 , wherein liquid-phase transalkylation is carried out in the transalkylation zone.

22. The process of claim 21 , wherein the transalkylation conditions comprises the absence of a molecular hydrogen stream co-fed into the transalkylation zone.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Rungta Meha
• Molinier Michel
• Nair Hari
• Levin Doron
• Weigel Scott J
• Salciccioli Michael

Classifications

• B01J23/63

  with rare earths or actinides · CPC title

• B01J37/0201

  Impregnation · CPC title

• B01J21/04

  Alumina · CPC title

• C07C5/2754

  with metals · CPC title

• C07C6/06 Primary

  at a cyclic carbon-to-carbon double bond · CPC title