# US 10,308,573 B2 · Process for maximizing xylenes production from heavy aromatics for use therein

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- Number: US 10,308,573 B2
- Document ID: US10308573B2
- Status: Granted
- Kind: B2
- Application number: 16/018,394
- Filed: 2018-06-26
- Published: 2018-11-29
- Granted: 2019-06-04
- Earliest claimed: 2017-05-26
- Assignees: Saudi Arabian Oil Company
- Applicants: Saudi Arabian Oil Company
- Inventors: Qi Xu; Raed Abudawoud; Ahmad A. Jazzar; Zhonglin Zhang
- Web page: https://patentgrep.com/patent/US10308573B2

## CPC

- C07C 15/08: Xylenes
- C07C 6/126: {of more than one hydrocarbon}
- C10G 45/44: Hydrogenation of the aromatic hydrocarbons
- C10G 45/46: characterised by the catalyst used
- C10G 45/72: Controlling or regulating
- C10G 47/00: Cracking of hydrocarbon oils, in the presence of hydrogen or hydrogen- generating compounds, to obtain lower boiling fractions (C10G15/00 takes precedence; destructive hydrogenation of non-melting solid carbonaceous or similar materials C10G1/06)
- C10G 65/043: {at least one step being a change in the structural skeleton}
- B01J 2219/00027: Process aspects
- B01J 2219/00051: Controlling the temperature
- C10G 2400/30: Aromatics
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

A method for producing xylenes from a heavy reformate feed includes the steps of introducing the heavy reformate feed and a hydrogen feed to a dealkylation reactor, reacting the heavy reformate feed with the hydrogen gas in the presence of the dealkylation catalyst in the dealkylation reactor to produce a dealkylation effluent, introducing the dealkylation effluent to a splitter unit, separating the dealkylation effluent into a light gas stream, a toluene stream, a benzene stream, a C9 aromatics stream, a C10+ aromatics stream, and a mixed xylene stream in the splitter unit, introducing the toluene stream, the C9 aromatics stream, and a hydrogen stream into a transalkylation reactor, reacting the toluene stream and the C9 aromatics stream in the presence of the transalkylation catalyst to produce a transalkylation effluent, introducing the transalkylation effluent to the splitter unit, and separating the transalkylation effluent in the splitter unit.

## Claims

### Claim 1

A method for producing mixed xylenes from a heavy reformate feed, the method comprising the steps of:
introducing the heavy reformate feed and a hydrogen feed to a dealkylation reactor, wherein the dealkylation reactor comprises a dealkylation catalyst, wherein the heavy reformate comprises toluene and aromatic hydrocarbons with nine or more carbon atoms (C9+ aromatics), wherein the hydrogen feed comprises hydrogen gas;
reacting the heavy reformate feed with the hydrogen gas in the presence of the dealkylation catalyst in the dealkylation reactor to produce a dealkylation effluent, wherein the dealkylation reactor is at a dealkylation temperature, wherein the dealkylation reactor is at a dealkylation pressure, wherein the dealkylation reactor has a liquid hourly space velocity;
introducing the dealkylation effluent to a splitter unit, where the dealkylation effluent comprises light gases, toluene, benzene, mixed xylenes, and C9+ aromatics;
separating the dealkylation effluent into a light gas stream, a toluene stream, a benzene stream, a C9 aromatics stream, a C10+ aromatics stream, and a mixed xylene stream in the splitter unit, wherein the light gas stream comprises light hydrocarbons and hydrogen, wherein the toluene stream comprises toluene, wherein the benzene stream comprises benzene, wherein the mixed xylene stream comprises mixed xylenes, wherein the C9 stream comprises C9 aromatics, wherein the C10+ aromatics stream comprises C10+ aromatics;
introducing the toluene stream, the C9 aromatics stream, and a hydrogen stream into a transalkylation reactor, wherein the transalkylation reactor comprises a transalkylation catalyst, wherein the hydrogen stream comprises hydrogen gas;
reacting the toluene stream and the C9 aromatics stream in the presence of the transalkylation catalyst to produce a transalkylation effluent, wherein the transalkylation reactor is at a transalkylation temperature, wherein the transalkylation reactor is at a transalkylation pressure, wherein the transalkylation reactor has a liquid hourly space velocity;
introducing the transalkylation effluent to the splitter unit, wherein the transalkylation effluent comprises light gases, toluene, benzene, mixed xylenes, and C9+ aromatics; and
separating the transalkylation effluent in the splitter unit such that mixed xylenes in the transalkylation effluent exit the splitter unit as part of the mixed xylene stream.

### Claim 2 (depends on 1)

The method of claim 1, wherein the heavy reformate feed contains between 0 wt % and 60 wt % toluene.

### Claim 3 (depends on 1)

The method of claim 1 further comprising the steps of:
introducing the light gas stream to a gas separator; and
separating the light gas stream into a produced hydrogen and a light gas product.

### Claim 4 (depends on 3)

The method of claim 3, where the gas separator comprises a pressure swing adsorption unit.

### Claim 5 (depends on 1)

The method of claim 1 further comprising the step of introducing the benzene stream to the transalkylation reactor.

### Claim 6 (depends on 1)

The method of claim 1 further comprising the step of supplying an added aromatic stream to the transalkylation reactor, such that there is an excess of toluene for transalkylation reactions in the transalkylation reactor.

### Claim 7 (depends on 1)

The method of claim 1, wherein the dealkylation temperature is between 200 deg C. and 500 deg C.

### Claim 8 (depends on 1)

The method of claim 1, wherein the dealkylation pressure is between 5 bar and 40 bar.

### Claim 9 (depends on 1)

The method of claim 1, wherein the liquid hourly space velocity in the dealkylation reactor is between 1 hr-1 and 10 hr-1.

### Claim 10 (depends on 1)

The method of claim 1, wherein the transalkylation temperature is between 300 deg C. and 500 deg C.

### Claim 11 (depends on 1)

The method of claim 1, wherein the transalkylation pressure is between 10 bar and 40 bar.

### Claim 12 (depends on 1)

The method of claim 1, wherein the liquid hourly space velocity in the transalkylation reactor is between 0.5 hr-1 and 6 hr-1.

### Claim 13 (depends on 1)

The method of claim 1, wherein an overall yield of the mixed xylenes in the mixed xylene stream is between 30 wt % and 89 wt %.

### Claim 14

A method for producing mixed xylenes from a heavy reformate feed, the method comprising the steps of:
introducing the heavy reformate feed and a hydrogen feed to a dealkylation reactor, wherein the dealkylation reactor comprises a dealkylation catalyst, wherein the heavy reformate comprises aromatic hydrocarbons with nine or more carbon atoms (C9+ aromatics), wherein the hydrogen feed comprises hydrogen gas;
reacting the heavy reformate feed with the hydrogen gas in the presence of the dealkylation catalyst in the dealkylation reactor to produce a dealkylation effluent, wherein the dealkylation reactor is at a dealkylation temperature, wherein the dealkylation reactor is at a dealkylation pressure, wherein the dealkylation reactor has a liquid hourly space velocity;
introducing the dealkylation effluent to a splitter unit, where the dealkylation effluent comprises light gases, toluene, benzene, mixed xylenes, and C9+ aromatics, where the splitter unit comprises multiple splitter columns;
separating the dealkylation effluent into a light gas stream, a toluene stream, a benzene stream, a C9 aromatics stream, a C10+ aromatics stream, and a mixed xylene stream in the splitter unit, wherein the light gas stream comprises light hydrocarbons and hydrogen, wherein the toluene stream comprises toluene, wherein the benzene stream comprises benzene, wherein the mixed xylene stream comprises mixed xylenes, wherein the C9 stream comprises C9 aromatics, wherein the C10+ aromatics stream comprises C10+ aromatics;
introducing the toluene stream, the C9 aromatics stream, and a hydrogen stream into a transalkylation reactor, wherein the transalkylation reactor comprises a transalkylation catalyst, wherein the hydrogen stream comprises hydrogen gas;
reacting the toluene stream and the C9 aromatics stream in the presence of the transalkylation catalyst to produce a transalkylation effluent, wherein the transalkylation reactor is at a transalkylation temperature, wherein the transalkylation reactor is at a transalkylation pressure, wherein the transalkylation reactor has a liquid hourly space velocity;
introducing the transalkylation effluent to the splitter unit, wherein the transalkylation effluent comprises light gases, toluene, benzene, mixed xylenes, and C9+ aromatics; and
separating the transalkylation effluent in the splitter unit such that mixed xylenes in the transalkylation effluent exit the splitter unit as part of the mixed xylene stream.

### Claim 15 (depends on 14)

The method of claim 14 further comprising the steps of:
introducing the light gas stream to a gas separator; and
separating the light gas stream into a produced hydrogen and a light gas product.

### Claim 16 (depends on 15)

The method of claim 15, where the gas separator comprises a pressure swing adsorption unit.

### Claim 17 (depends on 14)

The method of claim 14 further comprising the step of introducing the benzene stream to the transalkylation reactor.

### Claim 18 (depends on 14)

The method of claim 14 further comprising the step of supplying an added aromatic stream to the transalkylation reactor, such that there is an excess of toluene for transalkylation reactions in the transalkylation reactor.

### Claim 19 (depends on 14)

The method of claim 14, wherein the dealkylation temperature is between 200 deg C. and 500 deg C.

### Claim 20 (depends on 14)

The method of claim 14, wherein the dealkylation pressure is between 5 bar and 40 bar.

### Claim 21 (depends on 14)

The method of claim 14, wherein the liquid hourly space velocity in the dealkylation reactor is between 1 hr-1 and 10 hr-1.

### Claim 22 (depends on 14)

The method of claim 14, where the step of separating the dealkylation effluent comprises the steps of:
introducing the dealkylation effluent into a first column;
separating the dealkylation effluent in the first column to produce the light gas stream and a first column effluent;
introducing the first column effluent into a second column;
separating the first column effluent in the second column to produce a benzene/toluene stream and a second column effluent;
introducing the benzene/toluene stream into a third column;
separating the benzene/toluene stream in a third column to produce the benzene stream and the toluene stream;
introducing second column effluent into a fourth column;
separating the second column effluent in the fourth column to produce the mixed xylene stream and a C9+ aromatics stream;
introducing the C9+ aromatics stream into a fifth column; and
separating the C9+ aromatics stream in the fifth column to produce the C9 aromatics stream and the C10+ aromatics stream.

### Claim 23 (depends on 14)

The method of claim 14, wherein the transalkylation temperature is between 300 deg C. and 500 deg C.

### Claim 24 (depends on 14)

The method of claim 14, wherein the transalkylation pressure is between 10 bar and 40 bar.

### Claim 25 (depends on 14)

The method of claim 14, wherein the liquid hourly space velocity in the transalkylation reactor is between 0.5 hr-1 and 6 hr-1.

### Claim 26 (depends on 14)

The method of claim 14, wherein an overall yield of the mixed xylenes in the mixed xylene stream is between 30 wt % and 89 wt %.