Separation of methane from gas mixtures

Patent metadata

Field	Value
Publication number	US-10668425-B2
Application number	US-201715841603-A
Country	US
Kind code	B2
Filing date	Dec 14, 2017
Priority date	Dec 22, 2016
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

Processes for separating methane from a gas mixture that comprises methane and C2 gas, including C2+ gas, and other gases, including CO2 and H2S, that are based upon formation of gas hydrates, and systems useful for implementing such processes, are disclosed.

First claim

The invention claimed is:

1. A system for separation of C 1 gas from at least C 2+ gas comprising a hydrate formation reactor (HFR) that comprises an outer container configured:
with a plurality of stages arranged with a first stage proximal a first end of the container and second and any subsequent stages successively more proximal a second end of the container;
one or more gas feed inlets placed at a distance distal from the first end of the container the same as said distance of a stage that is a second or subsequent stage and configured to feed a gas stream into the container;
one or more aqueous solution inlets configured to feed an aqueous solution stream into the second end of the container or proximate thereto;
one or more hydrate slurry outlet configured to permit a draw off a hydrate slurry stream from the first end of the container or proximate thereto;
one or more gas or liquid product outlets configured to draw off a gas or liquid product stream, respectively, from the second end of the container or proximate thereto; and
a temperature control system, within the outer container, effective to establish a temperature ramp from a first temperature T 1 in a region proximate to the first end of the container to a second temperature T 2 in a region proximate to the second end of the container, wherein T 1 >T 2 ;
wherein the gas stream and the aqueous solution stream are arranged to flow in a countercurrent manner through the container.

2. The system of claim 1 that further comprises a solid-liquid separator configured to receive an aqueous hydrate slurry from the hydrate slurry outlet for separation into an aqueous phase product and a solid hydrate.

3. The system of claim 2 in which the solid-liquid separator comprises an aqueous phase recirculating line that feeds the aqueous phase product of the solid-liquid separator into the container.

4. The system of claim 3 in which the recirculating line includes a cooling plant for cooling the aqueous phase liquid product.

5. The system of claim 1 that further comprises a hydrate decomposition facility including a hydrate decomposition plant for decomposing a hydrate and a vapor-liquid separator for separating a vapor product from an aqueous phase and that is operably connected to the hydrate formation reactor so as to receive a hydrate slurry from the hydrate slurry outlet of the hydrate formation reactor.

6. The system of claim 5 , in which the hydrate decomposition plant comprises a heater for raising the temperature of the hydrate.

7. The system of system of claim 5 , in which the hydrate decomposition plant is one that lowers the pressure of a hydrate slurry.

8. The system of claim 5 , that further comprises an aqueous phase recirculating line that feeds the aqueous phase product of the vapor-liquid separator into the container.

9. The system of claim 8 , in which the aqueous phase recirculating line includes a cooling plant for cooling the aqueous phase liquid product.

10. The system of claim 1 that further comprises a gas feed mixer for adding a hydrate promoter to the gas feed stream.

11. The system of claim 2 that further comprises a gas feed mixer for adding a hydrate promoter to the gas feed stream.

12. The system of claim 8 that further comprises a gas feed mixer for adding a hydrate promoter to the gas feed stream.

13. The system of claim 3 , wherein the aqueous phase recirculating line includes an input for adding a hydrate promoter to the aqueous phase.

14. The system of claim 8 , wherein the aqueous phase recirculating line includes an input for adding a hydrate promoter to the aqueous phase.

15. The system of claim 12 , wherein the aqueous phase recirculating line includes an input for adding a hydrate promoter to the aqueous phase.

16. The system of claim 13 that further comprises a gas feed mixer for adding a hydrate promoter to the gas feed stream.

17. The system of claim 1 , in which the product gas outlet(s) are configured to transport the product gas to a storage facility for storing the product gas at a pressure above atmospheric pressure.

Assignees

• Exxonmobil Res & Eng Co
• Exxonmobil Res & Engineering Company

Inventors

• Mettler Matthew S
• Mhadeshwar Ashish B
• Gunther William R
• Billimoria Rustom M

Classifications

• B01D2257/702

  Hydrocarbons · CPC title

• C10L2270/10

  for transport, e.g. in pipelines as a gas hydrate slurry · CPC title

• B01D2256/245

  Methane · CPC title

• B01D2252/103

  Water · CPC title

• B01D53/1475

  Removing carbon dioxide · CPC title