US 2019/0101327 A1Published application

Natural Gas Liquefaction by a High Pressure Expansion Process

OwnerFritz PIERRE, JR.inventor

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Abstract

A method and system for liquefying a methane-rich high-pressure feed gas stream using a system having first and second heat exchanger zones and a compressed refrigerant stream. The compressed refrigerant stream is cooled and directed to the second heat exchanger zone to additionally cool it below ambient temperature. It is then expanded and passed through the first heat exchanger zone such that it has a temperature that is cooler, by at least 5° F., than the highest fluid temperature within the first heat exchanger zone. The feed gas stream is passed through the first heat exchanger zone to cool at least part of it by indirect heat exchange with the refrigerant stream, thereby forming a liquefied gas stream. At least a portion of the first warm refrigerant stream is directed to the second heat exchanger zone to cool the refrigerant stream, which is compressed.

Claims32

Dependent claims

A method for liquefying a feed gas stream rich in methane using a system having first and second heat exchanger zones, where the method comprises:

(a) providing the feed gas stream at a pressure less than 1,200 psia;
(b) providing a compressed refrigerant stream with a pressure greater than or equal to 1,500 psia;
(c) cooling the compressed refrigerant stream by indirect heat exchange with an ambient temperature air or water, to produce a compressed, cooled refrigerant stream;
(d) directing the compressed, cooled refrigerant stream to the second heat exchanger zone to additionally cool the compressed, cooled refrigerant stream below ambient temperature to produce a compressed, additionally cooled refrigerant stream;
(e) expanding the compressed, additionally cooled refrigerant stream in at least one work producing expander, thereby producing an expanded, cooled refrigerant stream;
(f) passing the expanded, cooled refrigerant stream through the first heat exchanger zone to form a first warm refrigerant stream, wherein the first warm refrigerant stream has a temperature that is cooler, by at least 5° F., than the highest fluid temperature within the first heat exchanger zone;
(g) passing the feed gas stream through the first heat exchanger zone to cool at least part of the feed gas stream by indirect heat exchange with the expanded, cooled refrigerant stream, thereby forming a liquefied gas stream;
(h) directing at least a portion of the first warm refrigerant stream to the second heat exchanger zone to cool by indirect heat exchange the compressed, cooled refrigerant stream, thereby forming a second warm refrigerant stream;
and
(i) compressing the second warm refrigerant stream to produce the compressed refrigerant stream.

7 more elements

A system for liquefying a feed gas stream rich in methane, the system having first and second heat exchanger zones and comprising:

a feed gas stream at a pressure less than 1,200 psia;
a compressed refrigerant stream with a pressure greater than or equal to 1,500 psia;
a cooler configured to cool the compressed refrigerant stream by indirect heat exchange with an ambient temperature air or water, to produce a compressed, cooled refrigerant stream;
at least one heat exchanger within the second heat exchanger zone, the compressed, cooled refrigerant stream being directed to the at least one heat exchanger within the second heat exchanger zone to additionally cool the compressed, cooled refrigerant stream below ambient temperature and thereby produce a compressed, additionally cooled refrigerant stream;
at least one work producing expander arranged to expand the compressed, additionally cooled refrigerant stream, thereby producing an expanded, cooled refrigerant stream;
at least one heat exchanger within the first heat exchanger zone, the expanded, cooled refrigerant stream being passed through the at least one heat exchanger in the first heat exchanger zone to form a first warm refrigerant stream, wherein the first warm refrigerant stream has a temperature that is cooler, by at least 5° F., than the highest fluid temperature within the first heat exchanger zone;
wherein the feed gas stream is passed through the first heat exchanger zone to cool at least part of the feed gas stream by indirect heat exchange with the expanded, cooled refrigerant stream, thereby forming a liquefied gas stream;
wherein at least a portion of the first warm refrigerant stream is directed to the second heat exchanger zone to cool by indirect heat exchange the compressed, cooled refrigerant stream, thereby forming a second warm refrigerant stream;
and
a compressor configured to compress the second warm refrigerant stream to produce the compressed refrigerant stream.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/112,093Filed 24 Aug 2018
Priority: 29 Sep 2017
Published: 4 Apr 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification29 codes

F25J 1/0022
Characterised by the fluid to be liquefied: hydrocarbons, e.g. natural gas
F25J 1/0035
Using the feed stream itself or separated fractions from it, i.e. "internal refrigeration": by gas expansion with extraction of work
F25J 1/0037
By gas expansion with extraction of work: of a return stream
F25J 1/0042
Using the feed stream itself or separated fractions from it, i.e. "internal refrigeration": by liquid expansion with extraction of work