System and method for liquefaction of natural gas

Patent metadata

Field	Value
Publication number	US-10480852-B2
Application number	US-201515533409-A
Country	US
Kind code	B2
Filing date	Dec 3, 2015
Priority date	Dec 12, 2014
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

A liquefaction system and method for producing liquefied natural gas (LNG) is provided. The liquefaction system may include a heat exchanger to cool natural gas to LNG, a first compressor to compress and combine first and second portions of a single mixed refrigerant from the heat exchanger, a first cooler to cool the single mixed refrigerant from the first compressor to a first liquid phase and a gaseous phase, and a first liquid separator to separate the first liquid phase from the gaseous phase. The liquefaction system may also include a second compressor to compress the gaseous phase, a second cooler to cool the compressed gaseous phase to a second liquid phase and the second portion of the single mixed refrigerant, a second liquid separator to separate the second liquid phase from the second portion of the single mixed refrigerant, and a pump to pressurize the first liquid phase.

First claim

We claim:

1. A method for producing liquefied natural gas, comprising:
fluidly coupling a source of natural gas to an inlet of a heat exchanger;
feeding natural gas from the source of natural gas through the inlet of the heat exchanger;
compressing a first portion of a single mixed refrigerant in a first compressor;
compressing a second portion of the single mixed refrigerant in the first compressor;
combining the first portion of the single mixed refrigerant with the second portion of the single mixed refrigerant in the first compressor to produce the single mixed refrigerant;
cooling the single mixed refrigerant in a first cooler to produce a first liquid phase and a gaseous phase;
separating the first liquid phase from the gaseous phase in a first liquid separator;
compressing the gaseous phase in a second compressor;
cooling the compressed gaseous phase in a second cooler to produce a second liquid phase and the second portion of the single mixed refrigerant;
separating the second liquid phase from the second portion of the single mixed refrigerant in a second liquid separator;
pressurizing the first liquid phase in a pump fluidly coupled with the first liquid separator;
combining the first liquid phase from the pump with the second liquid phase from the second liquid separator to produce the first portion of the single mixed refrigerant;
feeding the first portion of the single mixed refrigerant and the second portion of the single mixed refrigerant to the heat exchanger to cool at least a portion of the natural gas fed to the heat exchanger from the source of natural gas to produce the liquefied natural gas;
fluidly coupling a storage tank to an outlet of the heat exchanger; and
feeding the liquefied natural gas into the storage tank through the outlet of the heat exchanger.

2. The method of claim 1 , wherein compressing the first portion of the single mixed refrigerant in the first compressor comprises receiving the first portion of the single mixed refrigerant from the heat exchanger at a first stage of the first compressor.

3. The method of claim 1 , wherein compressing the second portion of the single mixed refrigerant in the first compressor comprises receiving the second portion of the single mixed refrigerant from the heat exchanger at an intermediate stage of the first compressor.

4. The method of claim 1 , wherein feeding the natural gas through the heat exchanger comprises:
feeding the natural gas through a pre-cooling zone of the heat exchanger; and
feeding the natural gas through a liquefaction zone of the heat exchanger.

5. The method of claim 4 , further comprising storing the liquefied natural gas in a storage tank fluidly coupled with the liquefaction zone of the heat exchanger.

6. The method of claim 1 , wherein feeding the first portion of the single mixed refrigerant and the second portion of the single mixed refrigerant to the heat exchanger comprises:
feeding the first portion of the single mixed refrigerant through a pre-cooling zone of the heat exchanger;
feeding the second portion of the single mixed refrigerant through the pre-cooling zone; and
pre-cooling the second portion of the single mixed refrigerant with the first portion of the single mixed refrigerant in the pre-cooling zone.

7. The method of claim 6 , wherein feeding the first portion of the single mixed refrigerant and the second portion of the single mixed refrigerant to the heat exchanger further comprises:
feeding the first portion of the single mixed refrigerant from the pre-cooling zone of the heat exchanger to an expansion valve fluidly coupled with the heat exchanger;
expanding the first portion of the single mixed refrigerant through the expansion valve to cool the first portion of the single mixed refrigerant; and
feeding the cooled first portion of the single mixed refrigerant from the expansion valve to the heat exchanger to cool the pre-cooled second portion of the single mixed refrigerant.

8. The method of claim 6 , wherein feeding the first portion of the single mixed refrigerant and the second portion of the single mixed refrigerant to the heat exchanger further comprises:
feeding the pre-cooled second portion of the single mixed refrigerant from the pre-cooling zone of the heat exchanger to an expansion valve fluidly coupled with the heat exchanger;
expanding the pre-cooled second portion of the single mixed refrigerant through the expansion valve to cool the pre-cooled second portion of the single mixed refrigerant; and
feeding the cooled second portion of the single mixed refrigerant from the expansion valve to the heat exchanger to cool the natural gas flowing therethrough.

9. The method of claim 1 , wherein the single mixed refrigerant comprises methane, ethane, propane, butanes, and nitrogen.

10. A method for producing liquefied natural gas from a natural gas source, comprising:
fluidly coupling a source of natural gas to an inlet of a heat exchanger;
feeding natural gas from the source of natural gas to and through the inlet of the heat exchanger;
feeding a first portion of a single mixed refrigerant from the heat exchanger to a first stage of a first compressor;
compressing the first portion of the single mixed refrigerant in the first compressor;
feeding a second portion of the single mixed refrigerant from the heat exchanger to an intermediate stage of the first compressor;
compressing the second portion of the single mixed refrigerant in the first compressor;
combining the first portion of the single mixed refrigerant with the second portion of the single mixed refrigerant in the first compressor to produce the single mixed refrigerant;
condensing at least a portion of the single mixed refrigerant in a first cooler fluidly coupled with the first compressor to produce a first liquid phase and a gaseous phase;
separating the first liquid phase from the gaseous phase in a first liquid separator fluidly coupled with the first cooler;
compressing the gaseous phase in a second compressor fluidly coupled with the first liquid separator;
cooling the compressed gaseous phase in a second cooler fluidly coupled with the second compressor to produce a second liquid phase and the second portion of the single mixed refrigerant;
separating the second liquid phase from the second portion of the single mixed refrigerant in a second liquid separator;
pressurizing the first liquid phase in a pump fluidly coupled with the first liquid separator;
combining the first liquid phase from the pump with the second liquid phase from the second liquid separator to produce the first portion of the single mixed refrigerant;
feeding the first portion of the single mixed refrigerant and the second portion of the single mixed refrigerant to the heat exchanger to cool at least a portion of the natural gas fed to the heat exchanger from the source of natural gas to produce the liquefied natural gas;
fluidly coupling a storage tank to an outlet of the heat exchanger; and
feeding the liquefied natural gas into the storage tank through the outlet of the heat exchanger.

11. The method of claim 10 , wherein feeding the first portion of the single mixed refrigerant and the second portion of the single mixed refrigerant to the heat exchanger comprises:
feeding the first portion of the single mixed refrigerant through a pre-cooling zone of the heat exchanger;
feeding the second portion of the single mixed refrigerant through the pre-cooling zone;
pre-cooling the second portion of the single mixed refrigerant with the first portion of the single mixed refrigerant in the pre-cooling zone;
feeding the first portion of the single mixed refrigerant from the pre-coo

Assignees

• Dresser Rand Co

Inventors

• Bardon Patrice
• Kim Hongpyo
• Romeike Matthew

Classifications

• F25J1/0097

  Others, e.g. F-, Cl-, HF-, HClF-, HCl-hydrocarbons etc. or mixtures thereof · CPC title

• F25J1/0022

  Hydrocarbons, e.g. natural gas · CPC title

• F25J1/0212

  as a single flow MCR cycle · CPC title

• F25J1/0291 Primary

  Refrigerant compression by combined gas compression and liquid pumping · CPC title

• F25J1/0055

  originating from an incorporated cascade · CPC title