US 2006/0218939 A1 · APPARATUS FOR THE LIQUEFACTION OF NATURAL GAS AND METHODS RELATING TO SAME

Abstract

An apparatus and method for producing liquefied natural gas. A liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream passes through an expander creating work output. A compressor may be driven by the work output and compresses the process stream. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. A portion of the liquid gas is used for additional cooling. Gas produced within the system may be recompressed for reintroduction into a receiving line or recirculation within the system for further processing.

Claims40

Dependent claims

A method of producing liquid natural gas, the method comprising:

providing a source of unpurified natural gas and flowing a portion of the natural gas from the source;
dividing the portion of natural gas into at least a process stream and a cooling stream;
flowing the process stream sequentially through a compressor and a first side of at least one heat exchanger;
flowing the cooling stream sequentially through an expander, a second side of the at least one heat exchanger;
sensing a temperature of the process stream after it exits the first side of the first heat exchanger;
flowing substantially all of the process stream from the first side of the at least one heat exchanger to the second side of the at least one heat exchanger if the sensed temperature is warmer than a specified temperature;
and
flowing at least a portion of the process stream from the first side of the at least one heat exchanger to a gas-liquid separator if the sensed temperature is colder than the specified temperature.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application

11/383,411Filed 15 May 2006

Priority

4 May 2001

Published

5 Oct 2006

Term ends

Not estimatedThe source records don’t support an estimate.

Classification22 codes

F25J 1/0022
Characterised by the fluid to be liquefied: hydrocarbons, e.g. natural gas
F25J 1/0037
By gas expansion with extraction of work: of a return stream
F25J 1/004
Using the feed stream itself or separated fractions from it, i.e. "internal refrigeration": by flash gas recovery
F25J 1/0045
Using the feed stream itself or separated fractions from it, i.e. "internal refrigeration": by vaporising a liquid return stream

Family

Application60/288,985Us provisional application · filed 4 May 2001

Application10/086,066Division · filed 27 Feb 2002

Application10/414,991Continuation in part · filed 14 Apr 2003

Application10/414,991Division · filed 14 Apr 2003

Application11/124,589Continuation in part · filed 5 May 2005

Application11/381,904Continuation in part · filed 5 May 2006

Application11/383,411Continuation in part · filed 15 May 2006

US 2002/0174678 A1Published application

US 2003/0192343 A1Published application

US 2006/0213223 A1Published application

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