Production of liquid hydrocarbons from polyolefins by supercritical water

Patent metadata

Field	Value
Publication number	US-11124707-B2
Application number	US-201916716999-A
Country	US
Kind code	B2
Filing date	Dec 17, 2019
Priority date	Dec 17, 2019
Publication date	Sep 21, 2021
Grant date	Sep 21, 2021

Abstract

Embodiments of the disclosure provide a method and system for recycling a plastic material to produce hydrocarbons. A plastic feed and a water feed are introduced to a first stage reactor. The first stage reactor is operated at a pressure equal to or greater than 22.06 MPa and a temperature equal to or greater than 373.9 deg. C. to produce an effluent stream. Residual solid components can be removed from the effluent stream. The effluent stream is introduced to a second stage reactor. The second stage reactor is operated at a pressure less than that of the first stage reactor but equal to or greater than 22.06 MPa and a temperature greater than that of the first stage reactor to produce a product stream. The plastic feed can include polyolefins. Optionally, a sulfur additive feed can be introduced either to the first stage reactor or the second stage reactor. Optionally, a residual oil feed can be introduced either to the first stage reactor or the second stage reactor.

First claim

What is claimed is:

1. A method for recycling a plastic material to produce hydrocarbons, the method comprising the steps of:
introducing a plastic feed and a water feed to a first stage reactor, wherein the plastic feed comprises the plastic material, wherein the first stage reactor is operated at a pressure equal to or greater than 22.06 MPa and a temperature equal to or greater than 373.9 deg. C to produce an effluent stream, wherein the effluent stream comprises a mixture of the plastic material and water;
separating unreacted solid components from the effluent stream in a separation device to produce a waste stream and a feed stream, where the unreacted solid components in the waste stream are selected from the group consisting of unreacted plastic material, coke, char, and combinations of the same; and
introducing the feed stream to a second stage reactor, wherein the second stage reactor is operated at a pressure less than that of the first stage reactor but equal to or greater than 22.06 MPa and a temperature greater than that of the first stage reactor to produce a product stream, wherein the product stream comprises the hydrocarbons.

2. The method of claim 1 , wherein the plastic material comprises polyolefins selected from the group consisting of: polyethylene, polypropylene, polybutylene, and combinations of the same.

3. The method of claim 1 , wherein the first stage reactor is operated at a pressure ranging between 27 MPa and 35 MPa and a temperature ranging between 380 deg. C and 420 deg. C.

4. The method of claim 1 , wherein the second stage reactor is operated at a pressure ranging between 24 MPa and 27 MPa and a temperature ranging between 420 deg. C and 470 deg. C.

5. The method of claim 1 , further comprising the step of:
introducing a sulfur additive feed to the first stage reactor by combining the sulfur additive feed and the water feed, wherein the sulfur additive feed comprises sulfur-containing hydrocarbons selected from the group consisting of: thiols, sulfides, disulfides, and combinations of the same.

6. The method of claim 5 , wherein the sulfur additive feed has a total sulfur content of greater than 5 wt. %.

7. The method of claim 1 , further comprising the step of:
introducing a sulfur additive feed to the second stage reactor by combining the sulfur additive feed and the feed stream, wherein the sulfur additive feed comprises sulfur-containing hydrocarbons selected from the group consisting of: thiols, sulfides, disulfides, and combinations of the same.

8. The method of claim 7 , wherein the sulfur additive feed has a total sulfur content of greater than 5 wt. %.

9. The method of claim 1 , further comprising the step of:
introducing a residual oil feed to the first stage reactor by combining the residual oil feed and the plastic feed, wherein the residual oil feed comprises a residual oil selected from the group consisting of: atmospheric residue, vacuum residue, and combinations of the same.

10. The method of claim 9 , wherein the residual oil has a total sulfur content of greater than 0.1 wt. %, wherein the residual oil comprises sulfur-containing hydrocarbons selected from the group consisting of: thiols, sulfides, disulfides, and combinations of the same.

11. The method of claim 1 , further comprising the step of:
introducing a residual oil feed to the second stage reactor by combining the residual oil feed and the feed stream, wherein the residual oil feed comprises a residual oil selected from the group consisting of: atmospheric residue, vacuum residue, and combinations of the same.

12. The method of claim 11 , wherein the residual oil has a total sulfur content of greater than 0.1 wt. %, wherein the residual oil comprises sulfur-containing hydrocarbons selected from the group consisting of: thiols, sulfides, disulfides, and combinations of the same.

13. The method of claim 1 , further comprising the step of:
cooling the product stream to a temperature ranging between 80 deg. C and about 120 deg. C.

14. The method of claim 1 , further comprising the step of:
depressurizing the product stream to a pressure ranging between 1 MPa and 5 MPa.

15. The method of claim 1 , further comprising the step of:
introducing the product stream to a separator to produce a gas product stream, a liquid product stream, and a water product stream, wherein the gas product stream comprises gaseous hydrocarbons, wherein the liquid product stream comprises liquid hydrocarbons.

Assignees

• Saudi Arabian Oil Co

Inventors

• Choi Ki-Hyouk
• Alnasir Ali S
• Albahar Mohammed Z

Classifications

• B09B3/40

  involving thermal treatment, e.g. evaporation (processes using mineral binders involving a melting or softening step B09B3/29; involving radiation B09B3/50) · CPC title

• C10G2300/80

  Additives · CPC title

• C10G2300/4012

  Pressure · CPC title

• C10G2300/4006

  Temperature · CPC title

• C10G2300/202

  Heteroatoms content, i.e. S, N, O, P · CPC title