Pyrolysis product compression using CO2 loop

Patent metadata

Field	Value
Publication number	US-12352204-B2
Application number	US-202017782679-A
Country	US
Kind code	B2
Filing date	Dec 18, 2020
Priority date	Dec 30, 2019
Publication date	Jul 8, 2025
Grant date	Jul 8, 2025

Abstract

Processes, systems, and apparatus are provided for producing a compressed process gas comprising light olefin such as ethylene. The process utilizes a pyrolysis reactor to produce the process gas. A power generator utilizes a turbine operated based on an Allam cycle to produce shaft power for operating one or more compressors involved in processing of the process gas while producing a reduced or minimized amount of CO 2 that is released as a low-pressure gas phase product. Examples of using the shaft power for processing of the process gas can include compressing the process gas a process gas compressor powered by the produced shaft power and cooling the process gas using a refrigeration compressor powered by the produced shaft power.

First claim

The invention claimed is:

1. A process for producing and compressing a process gas, the process comprising:
separating air to form at least an oxygen-containing stream, the oxygen-containing stream comprising 90 vol. % or more O 2 ;
combusting at least a portion of a fuel with at least a portion of the oxygen-containing stream in the presence of at least a portion of a recycle stream to produce a heated working fluid, the recycle stream comprising 80 vol. % or more CO 2 ;
expanding the heated working fluid to produce shaft power and a decompressed working fluid comprising at least CO 2 and H 2 O;
pyrolyzing at least a portion of a hydrocarbon-containing feed to produce a process gas comprising ethylene;
separating the decompressed working fluid by performing a series of cooling and compressing steps to form a water stream and a CO 2 -containing stream, the CO 2 in the decompressed working fluid and the CO 2 -containing stream being in a supercritical state during the series of cooling and compressing steps;
transferring at least part of the shaft power a) to a process gas compressor to compress the process gas, b) to a refrigeration compressor to cool the process gas, c) to a refrigeration compressor to cool the decompressed working fluid in a cooling step from the series of cooling and compressing steps, or d) a combination of two or more of a), b) and c); and
compressing at least a portion of the CO 2 -containing stream to form a compressed CO 2 -containing stream, the recycle stream comprising at least a first portion of the compressed CO 2 -containing stream.

2. The process of claim 1 , wherein the decompressed working fluid comprises 90 vol. % or more of CO 2 and H 2 O.

3. The process of claim 1 , wherein the transfer of the shaft power comprises direct power transfer, indirect power transfer, or a combination thereof.

4. The process of claim 1 , wherein the fuel comprises one or more of (i) natural gas, (ii) hydrocarbon in the natural gas, (iii) hydrocarbon separated from the natural gas and/or derived from the natural gas, (iv) natural gas condensate, (v) hydrocarbon in the natural gas condensate, (vi) hydrocarbon separated from the natural gas condensate and/or derived from the natural gas condensate, (vii) crude oil, (viii) hydrocarbon in the crude oil, (viii) hydrocarbon separated from the crude oil and or derived from the crude oil, and (ix) molecular hydrogen.

5. The process of claim 1 , wherein the feed comprises >10 wt. % C 2 + hydrocarbon.

6. The process of claim 1 , wherein the compressed CO 2 -containing stream comprises a pressure of 200 bar or more.

7. The process of claim 1 , wherein the at least a portion of the shaft power is transferred a) to a process gas compressor to compress the process gas, b) to a refrigeration compressor to cool the process gas, or e) a combination of a) and b).

8. The process of claim 1 , further comprising transferring at least a second portion of the shaft power to a compressor for i) performing the compressing in the series of cooling and compressing steps, ii) refrigeration to perform at least a portion of the cooling in the series of cooling and compressing steps, iii) performing the compressing of the CO 2 -containing stream, or iv) a combination of two or more of i), ii) and iii).

9. The process of claim 1 , wherein the pyrolyzing is carried out in at least one steam cracking furnace.

10. The process of claim 1 , wherein the pyrolyzing is carried out in at least one reverse-flow thermal pyrolysis reactor.

11. The process of claim 1 , wherein the fuel comprises at least a portion of a tail gas recovered from the process gas.

12. The process of claim 1 , wherein at least a portion of the water stream is (i) fed into pyrolyzing step to mix with the hydrocarbon-containing feed; (ii) heated to generate steam; (iii) used as an indirect cooling medium; (iv) used as a quenching medium; and (iv) fed into a hydrocarbon-containing stream as a diluent.

13. The process of claim 1 , further comprising:
recovering an ethylene stream from the process gas stream;
contacting at least a portion of the ethylene stream with at least a portion of the oxygen-containing stream to produce an oxidized stream; and
producing a monoethylene glycol product from the oxidized stream.

14. The process of claim 13 , wherein the oxidized stream comprises ethylene oxide, and the step of producing the monoethylene glycol product comprises contacting the ethylene oxide with the CO 2 sourced from the compressed CO 2 stream and/or the CO 2 -containing stream.

15. The process of claim 1 , further comprising at least one of the following:
supplying a portion of the compressed CO 2 stream to a storage;
conducting away a portion of the compressed CO 2 stream in a pipeline;
using a portion of the compressed CO 2 stream to extract a hydrocarbon source material, and deriving at least a portion of the hydrocarbon-containing feed from the hydrocarbon source material.

16. The process of claim 1 , wherein the pyrolyzing is performed under pyrolysis conditions comprising a temperature in the range of from 773K to 1773K, a total pressure ≥34 kPag, and a hydrocarbon partial pressure of ≥48 kPa.

17. The process of claim 1 , further comprising carrying out the pyrolyzing of step for a time interval t P , and regenerating a reverse-flow thermal pyrolysis reactor during a time interval t R , wherein t P and t R are substantially non-overlapping time intervals.

18. The process of claim 1 ,
wherein combusting at least a portion of the fuel comprises combusting a first portion of the fuel with a first portion of the oxygen-containing stream in the presence of a first portion of the recycle stream in a first combustion zone to produce a first heated working fluid and combusting a second portion of the fuel with a second portion of the oxygen-containing stream in the presence of a second portion of the recycle stream in a second combustion zone to produce a second heated working fluid,
wherein the first heated working fluid is expanded to produce first shaft power, and
wherein the second heated working fluid expanded to produce second shaft power.

Assignees

• Exxonmobil Chemical Patents Inc
• Exxonmobil Engineering & Tech Company

Inventors

• Rooney Mark A
• Keusenkothen Paul F

Classifications

• C10G2300/4012

  Pressure · CPC title

• C10G9/002 Primary

  Cooling of cracked gases · CPC title

• F02C3/10

  with another turbine driving an output shaft but not driving the compressor · CPC title

• F02C1/10

  Closed cycles · CPC title

• Y02P30/40

  Ethylene production · CPC title