Transalkylation start-up processes for supported precious metal catalyst

Patent metadata

Field	Value
Publication number	US-11331658-B2
Application number	US-202016816762-A
Country	US
Kind code	B2
Filing date	Mar 12, 2020
Priority date	Mar 27, 2019
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

Processes for activating precious metal-containing catalysts. The processes can decrease the amount of high purity hydrogen required for starting up a catalytic conversion process such as transalkylation of heavy aromatics, without detrimental impact to the metal activity. The processes can include a low temperature treatment step with a high purity first gas, such as hydrogen generated by electrolysis and/or reformer hydrogen diluted with high purity inert gas, and a high temperature treatment step with a low purity second gas such as the reformer hydrogen. Also, the processes can include mixing a hydrogen gas of high or low purity with a high purity inert gas to form a gas mixture with a proportion of hydrogen no less than 2% and a reduced carbon monoxide concentration relative to the low purity hydrogen, and contacting the catalyst with the gas mixture.

First claim

What is claimed is:

1. A process for activating a catalyst composition comprising a precious metal, the process comprising:
(I) providing the catalyst composition comprising the precious metal, wherein the concentration of the precious metal in the catalyst composition is from 0.01 wt % to 5.0 wt %, expressed as weight percentage of the precious metal based on the total weight of the catalyst composition;
(II) contacting the catalyst composition with a first gas at a first temperature in a range from 150° C. to 300° C., the first gas comprising hydrogen and no more than 1 vppm carbon monoxide, based on the total volume of the first gas; and
(III) after step (II), contacting the catalyst composition with a second gas comprising hydrogen at a second temperature not lower than 340° C., wherein the second gas further comprises carbon monoxide at a concentration of no less than 1 vppm, based on the total volume of the second gas.

2. The process of claim 1 , wherein the first gas further comprises an inert gas.

3. The process of claim 2 , wherein the first gas is formed by diluting a reformer hydrogen with a high purity inert gas to decrease the carbon monoxide concentration of the resulting first gas relative to the reformer hydrogen.

4. The process of claim 1 , wherein the second gas comprises carbon monoxide at a concentration of no less than 3 vppm and no greater than 20 vppm, based on the total volume of the second gas.

5. The process of claim 1 , wherein the first gas comprises at least 2 volume percent hydrogen and no more than 98 volume percent inert gas.

6. The process of claim 1 , wherein the first gas comprises carbon monoxide at a concentration of no greater than 0.5 vppm.

7. The process of claim 1 , wherein the first gas comprises an electrolytic hydrogen stream formed by electrolytic decomposition of water.

8. The process of claim 1 , wherein the catalyst composition comprises the precious metal at a concentration no greater than 0.1 wt %, based on the total weight of the catalyst composition.

9. The process of claim 1 , the process further comprising, after step (I) and before step (II):
(Ia) heating the catalyst composition in the presence of the first gas from ambient temperature to the first temperature.

10. The process of claim 9 , wherein the heating in respective steps (Ia) and (IIa) comprises heating the catalyst composition at a temperature elevation rate in a range from 0.01° C. per minute to 5° C. per minute.

11. The process of claim 1 , wherein the process further comprises, after step (II) and before step (III):
(IIa) heating the catalyst composition from the first temperature to the second temperature in the presence of the first gas, the second gas, or a mixture of both.

12. The process of claim 1 , wherein the process further comprises:
(I-A) after step (I) and before step (II), disposing the catalyst composition in a reactor;
(I-B) after step (I-A), purging the catalyst composition and the reactor with an inert gas; and
(I-C) after step (I-B), purging the catalyst composition and the reactor with the first gas.

13. The process of claim 1 , further comprising:
wherein in step (II), the catalyst composition is held in proximity to the first temperature in the presence of the first gas for a period of from 1 hour to 24 hours; and/or wherein in step (III), the catalyst composition is held in proximity to the second temperature in the presence of the second gas for a period of from 0.2 hour to 8 hours.

14. The process of claim 1 , further comprising:
wherein the second temperature is no higher than 515° C.; and/or
wherein first and second gases have an absolute hydrogen partial pressure in a range from 2 kPa to 5000 kPa.

15. The process of claim 1 , wherein step (I) comprises:
(I.1) providing a zeolite;
(I.2) impregnating the zeolite with a solution of the precious metal to obtain an impregnated zeolite;
(I.3) drying the impregnated zeolite to obtain a catalyst precursor; and
(I.4) calcining the catalyst precursor to obtain the catalyst composition.

16. The process of claim 1 , the process further comprising:
(IV) contacting the catalyst composition with a sulfur-containing agent during or after step (III) to sulfide at least a portion of the catalyst composition.

17. The process of claim 1 , wherein the catalyst composition is for converting an aromatic hydrocarbon, wherein the process further comprises, after step (III):
(V) contacting the catalyst composition with one or more aromatic hydrocarbons and hydrogen under reaction conditions effective to convert the one or more aromatic hydrocarbons.

18. The process of claim 17 , wherein:
the catalyst composition is a transalkylation catalyst;
the one or more aromatic hydrocarbons comprise C9+ aromatic hydrocarbons and C7− aromatic hydrocarbons;
the reaction conditions include:
a weight hourly space velocity (WHSV) of the aromatic hydrocarbons from 0.2 to 100 h −1 ;
an absolute pressure of from 380 kPa to 3550 kPa;
a molar ratio of hydrocarbons to hydrogen of from 1 to 5; and
a reactor inlet temperature of from 340° C. to 515° C.; and

the process produces a transalkylation product mixture comprising C8 aromatic hydrocarbons.

19. A process for activating a catalyst composition, the process comprising the following steps in the following order:
(i) providing a catalyst composition comprising a precious metal at a concentration from 0.01 wt % to 5.0 wt %, based on the total weight of the catalyst composition;
(ii) disposing the catalyst composition in a reactor;
(iii) purging the catalyst composition and the reactor with an inert gas;
(iv) purging the catalyst composition and the reactor with a first gas comprising carbon monoxide at a concentration no greater than 0.5 vppm;
(v) heating the catalyst composition from an ambient temperature to a first temperature in a range from 150° C. to 300° C.;
(vi) maintaining the catalyst composition in proximity to the first temperature for a period from 1 hour to 24 hours in the presence of the first gas;
(vii) heating the catalyst composition from the first temperature to a second temperature no less than 340° C.; and
(viii) maintaining the catalyst composition in proximity to the second activation temperature for a period from 0.1 hour to 8 hours in the presence of a second gas comprising carbon monoxide at a concentration no less than 1 vppm.

20. A process for activating a catalyst composition comprising a precious metal, the process comprising:
(I) providing the catalyst composition comprising the precious metal, wherein the concentration of the precious metal in the catalyst composition is from 0.01 wt % to 5.0 wt %, expressed as weight percentage of the precious metal based on the total weight of the catalyst composition;
(II) mixing a high purity inert gas comprising no more than 1 vppm carbon monoxide, with a hydrogen gas stream comprising no less than 1 vppm and no more than 20 vppm carbon monoxide, to form a gas mixture comprising no less than 2 percent hydrogen by volume; and
(III) contacting the catalyst composition with the gas mixture at a temperature no lower than 150° C.

21. The process of claim 20 , wherein the high purity inert gas comprises nitrogen and has a concentration of carbon monoxide no more than 0.1 vppm.

22. The process of claim 20 , further comprising, before step (II), producing the hydrogen gas stream by a hydrocarbon reforming process.

23. The process of claim 20 ,

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Podsiadlo Paul
• Tinger Robert G
• Detjen Todd E
• Ramos Jesus A
• Andrews Jeffrey L
• Sparks Travis D

Classifications

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• B01J37/20

  Sulfiding · CPC title

• C01B2203/0238

  the reforming step being a carbon dioxide reforming step · CPC title

• B01J29/061

  containing metallic elements added to the zeolite · CPC title

• B01J6/001

  Calcining · CPC title