Natural Gas Liquefaction Process
First Claim
1. A process for liquefying a gas stream rich in methane, said process comprising:
- (a) providing said gas stream at a pressure less than 1,200 pounds per square inch absolute (psia);
(b) withdrawing a portion of said gas stream for use as a refrigerant;
(c) compressing said refrigerant to a pressure greater than its pressure in (a) to provide a compressed refrigerant;
(d) cooling said compressed refrigerant by indirect heat exchange with an ambient temperature cooling fluid to a process temperature above about 35 degrees Fahrenheit (°
F.) (1.7°
C.);
(e) subjecting the cooled, compressed refrigerant to supplemental cooling so as to reduce further its temperature thereby producing a supplementally cooled, compressed refrigerant, wherein the supplementally cooled, compressed refrigerant of (e) is from 10°
F. to 70°
F. (6°
C. to 39°
C.) cooler than said process temperature resulting in a supplementally cooled, compressed refrigerant temperature from 10°
F. to 60°
F. (6°
C. to 15.6°
C.);
(f) expanding the refrigerant of (e) to further cool said refrigerant, thereby producing an expanded, supplementally cooled refrigerant;
(g) passing said expanded, supplementally cooled refrigerant to a heat exchange area and(h) passing said gas stream through said heat exchange area to cool at least part of said gas stream by indirect heat exchange with said expanded, supplementally cooled refrigerant, thereby forming a cooled fluid stream.
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Accused Products
Abstract
The invention relates to a process for liquefying a gas stream rich in methane, said process comprising: (a) providing said gas stream; (b) withdrawing a portion of said gas stream for use as a refrigerant; (c) compressing said refrigerant; (d) cooling said compressed refrigerant with an ambient temperature cooling fluid; (e) subjecting the cooled, compressed refrigerant to supplemental cooling; (f) expanding the refrigerant of (e) to further cool said refrigerant, thereby producing an expanded, supplementally cooled refrigerant; (g) passing said expanded, supplementally cooled refrigerant to a heat exchange area; and, (h) passing said gas stream of (a) through said heat exchange area to cool at least part of said gas stream by indirect heat exchange with said expanded, supplementally cooled refrigerant, thereby forming a cooled gas stream. In further embodiments for improved efficiencies, additional supplemental cooling may be provided after one or more other compression steps.
72 Citations
12 Claims
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1. A process for liquefying a gas stream rich in methane, said process comprising:
-
(a) providing said gas stream at a pressure less than 1,200 pounds per square inch absolute (psia); (b) withdrawing a portion of said gas stream for use as a refrigerant; (c) compressing said refrigerant to a pressure greater than its pressure in (a) to provide a compressed refrigerant; (d) cooling said compressed refrigerant by indirect heat exchange with an ambient temperature cooling fluid to a process temperature above about 35 degrees Fahrenheit (°
F.) (1.7°
C.);(e) subjecting the cooled, compressed refrigerant to supplemental cooling so as to reduce further its temperature thereby producing a supplementally cooled, compressed refrigerant, wherein the supplementally cooled, compressed refrigerant of (e) is from 10°
F. to 70°
F. (6°
C. to 39°
C.) cooler than said process temperature resulting in a supplementally cooled, compressed refrigerant temperature from 10°
F. to 60°
F. (6°
C. to 15.6°
C.);(f) expanding the refrigerant of (e) to further cool said refrigerant, thereby producing an expanded, supplementally cooled refrigerant; (g) passing said expanded, supplementally cooled refrigerant to a heat exchange area and (h) passing said gas stream through said heat exchange area to cool at least part of said gas stream by indirect heat exchange with said expanded, supplementally cooled refrigerant, thereby forming a cooled fluid stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
Specification