Natural gas processing using supercritical fluid power cycles

Patent metadata

Field	Value
Publication number	US-11821682-B2
Application number	US-202217586081-A
Country	US
Kind code	B2
Filing date	Jan 27, 2022
Priority date	Sep 28, 2018
Publication date	Nov 21, 2023
Grant date	Nov 21, 2023

Abstract

The systems and methods described herein integrate a supercritical fluid power generation system with a LNG production/NGL separation system. A heat exchanger thermally couples the supercritical fluid power generation system with the LNG production/NGL separation system. A relatively cool heat transfer medium, such as carbon dioxide, passes through the heat exchanger and cools a first portion of extracted natural gas. The relatively warm heat transfer medium returns to the supercritical fluid power generation system where a compressor and a thermal input device, such as a combustor, are used to increase the pressure and temperature of the heat transfer medium above its critical point to provide a supercritical heat transfer medium. A second portion of the extracted natural gas may be used as fuel for the thermal input device.

First claim

What is claimed is:

1. A natural gas processing method, comprising:
with a supercritical fluid power generation system:
receiving a thermal energy input
generating a multiphase heat transfer medium comprising carbon dioxide at a temperature T 1 and a pressure P 1 ; and
generating a power output;

with a natural gas compression subsystem of a LNG production/LNG separation system that receives a first portion of extracted natural gas and separately receives at least a portion of the power output from the supercritical fluid power generation system, and providing the first portion of the extracted natural gas at a temperature T 2 and pressure P 2 , wherein T 2 >T 1 ;
with a heat exchanger of the LNG production/LNG separation system fluidly coupled to the supercritical fluid power generation system, the natural gas compression subsystem, and a natural gas liquid subsystem of the LNG production/LNG separation system:
receiving the multiphase heat transfer medium at T 1 , P 1 from the supercritical power generation system;
cooling the first portion of the extracted natural gas at T 2 , P 2 with the multiphase heat transfer medium at T 1 , P 1 to produce extracted natural gas at a temperature T 3 and a pressure P 3 , wherein T 3 <T 2 ;
evaporating at least a portion of the multiphase heat transfer medium to provide a gaseous heat transfer medium at a temperature T 4 and a pressure P 4 , wherein T 4 >T 3 ; and
conveying the gaseous heat transfer medium at T 4 , P 4 to the supercritical fluid power generation system; and

receiving, with the natural gas liquid subsystem, at least a portion of the power output from the supercritical fluid power generation system.

2. The natural gas processing method of claim 1 , wherein the natural gas compression subsystem comprises a natural gas compressor, and the method further comprises, with the natural gas compressor:
receiving the first portion of the extracted natural gas at a temperature T 5 and a pressure P 5 ; and
increasing the temperature and pressure of the first portion of the extracted natural gas at T 5 , P 5 to provide the first portion of the extracted natural gas at T 2 , P 2 , wherein T 2 >T 5 and P 2 >P 5 .

3. The natural gas processing method of claim 1 , further comprising condensing, with the natural gas liquid subsystem, the first portion of extracted natural gas at T 3 , P 3 to provide a liquefied natural gas (LNG) product at a temperature T 6 and a pressure P 6 .

4. The natural gas processing method of claim 3 , further comprising providing, with the natural gas liquid subsystem, a natural gas liquid (NGL) product at a temperature T 7 and a pressure P 7 .

5. The natural gas processing method of claim 1 , wherein the supercritical fluid power generation system further comprises a combustor and the method further comprises, with the combustor:
combusting a second portion of the extracted natural gas; and
providing a supercritical heat transfer medium at T 8 and a pressure P 8 .

6. The natural gas processing method of claim 5 , wherein the supercritical fluid power generation system further comprises a turbine fluidly coupled to the combustor, a first compressor, a cooling system fluidly coupled to the first compressor and the turbine, a second compressor fluidly coupled to the cooling system, and an expansion valve, and the method further comprises:
with the turbine:
receiving the supercritical heat transfer medium at T 8 , P 8 ; and
expanding the supercritical transfer medium at T 8 , P 8 to produce the power output and a gaseous heat transfer medium at a temperature T 9 and a pressure P 9 ;

with the first compressor:
receiving the gaseous heat transfer medium at T 4 , P 4 from the heat exchanger; and
compressing the gaseous heat transfer medium at T 4 , P 4 to provide a gaseous heat transfer medium at a temperature T 10 and a pressure P 10 ;

with the cooling system, receiving at least a portion of the gaseous heat transfer medium at T 9 , P 9 and at least a portion of the gaseous heat transfer medium at T 10 , P 10 to produce a gaseous heat transfer medium at a temperature T 11 and a pressure P 11 ;
with the second compressor:
receiving the gaseous heat transfer medium at T 11 , P 11 ; and
compressing and cooling the gaseous heat transfer medium at T 11 , P 11 to provide a liquid heat transfer medium at a temperature T 12 and a pressure P 12 ; and

with the expansion valve:
receiving the liquid heat transfer medium at T 12 , P 12 ; and
expanding at least a portion of the liquid heat transfer medium at T 12 , P 12 to provide the multiphase heat transfer medium at T 1 , P 1 .

7. The natural gas processing method of claim 1 , wherein the supercritical fluid power generation system comprises a recuperated indirect-fired Brayton cycle recuperative power generation system.

8. The natural gas processing method of claim 1 , wherein the supercritical fluid power generation system comprises a direct-fired Brayton cycle power generation system.

9. The natural gas processing method of claim 8 , wherein the direct-fired Brayton cycle power generation system comprises a recuperated direct-fired Brayton cycle power generation system.

10. The natural gas processing method of claim 8 , further comprising, with said direct-fired Brayton cycle power generation system, providing a blowdown comprising carbon dioxide and water.

11. The natural gas processing method of claim 1 , wherein the heat exchanger comprises one or more microchannel heat exchangers.

Assignees

• Southwest Res Inst

Inventors

• Beck Griffin C
• Ransom David L
• Hoopes Kevin M

Classifications

• E21B23/0415

  using particular fluids, e.g. electro-active liquids · CPC title

• E21B23/0412

  characterised by pressure chambers, e.g. vacuum chambers · CPC title

• E21B47/0175

  Cooling arrangements · CPC title

• F25J1/0095 Primary

  Oxides of carbon, e.g. CO2 · CPC title

• E21B43/34

  Arrangements for separating materials produced by the well · CPC title