Multi-component refrigeration process for liquefaction of natural gas
AssigneeExxon Production Research Company
InventorsRonald R. Bowen, Eric T. Cole, Edward L. Kimble, Eugene R. Thomas, Lonny R. Kelley
Life of this patent
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Abstract
This invention relates to a process for liquefying a pressurized gas stream rich in methane in which the liquefication of the gas stream occurs in a heat exchanger being cooled by a closed-loop multi-component refrigeration system to produce a methane-rich liquid product having a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the liquid product to be at or below its bubble point. The liquefied gas product is then introduced to a storage means at a temperature above about -112.degree. C. (-170.degree. F.).
Claims21
A process for liquefying a pressurized gas stream rich in methane which comprises the steps of liquefying the gas stream in a heat exchanger being cooled by a closed-loop multi-component refrigeration system to produce a methane-rich liquid product having a temperature above about - 112.degree. C. (-170.degree. F.) and a pressure sufficient for the liquid product to be at or below its bubble point, and introducing the liquid product to a storage means at a temperature above about -112.degree. C. (-170.degree. F.).
A process for liquefying a natural gas stream comprising methane, propane, and heavier hydrocarbons to produce liquefied natural gas having a pressure higher than about 1724 kPa (250 psia) and a temperature above about -112 .degree. C. (-170.degree. F.), which process comprises:
- (a) passing the natural gas stream to the first cooling zone of a multi-component heat exchanger, the multi-component heat exchanger comprising three cooling zones, with the second cooling zone operating at a temperature below the temperature of the first cooling zone and above the temperature of the third cooling zone;
- (b) fractionating the cooled natural gas feed stream to separate a methane-rich stream from heavier hydrocarbons stream;
- (c) fractionating the heavier hydrocarbons stream to produce a ethane-rich stream and a stream containing hydrocarbons heavier than ethane and removing the hydrocarbons heavier than ethane from the process;
- (d) combining the methane-rich stream of step (b) and the ethane-rich stream of step (c) and passing the combined stream to the second cooling zone of the multi-component refrigeration system and cooling the combined stream to produce a subcooled condensate;
- (e) expanding at least a portion of the subcooled condensate to provide liquefied natural gas having a pressure higher than about 1724 kPa (250 psia) and a temperature above about -112.degree. C. (-170.degree. F.);
- and
- (f) passing to the third cooling zone of the multi-component refrigeration system gas resulting from the evaporation of a liquefied natural gas contained in a storage vessel to produce a second liquefied natural gas stream and combining the second liquefied natural gas stream with the liquefied natural gas produced in step (e).
A process for liquefying a natural gas stream comprising methane, propane, and heavier hydrocarbons to produce liquefied natural gas having a pressure higher than about 1724 kPa (250 psia) and a temperature above about -112 .degree. C. (-170.degree. F.), which process comprises:
- (a) cooling the natural gas stream by a propane refrigeration system;
- (b) fractionating the cooled natural gas stream to separate a methane-rich stream and heavier hydrocarbons stream;
- (c) fractionating the heavier hydrocarbons stream to produce a ethane-rich stream and at least one stream containing hydrocarbons heavier than ethane and removing the hydrocarbons heavier than ethane from the process;
- (d) combining the methane-rich stream of step (b) and the ethane-rich stream of step (c) and passing the combined stream to the first cooling zone of a multi-component refrigeration system having a first cooling zone refrigerated by a multi-component liquid and a multi-component vapor in heat exchange relationship with the combined methane-rich stream and the ethane-rich stream to produce a subcooled condensate;
- and
- (e) expanding at least a portion of the subcooled condensate to provide liquefied natural gas having a pressure higher than about 1724 kPa (250 psia) and a temperature above about -112 .degree. C. (-170.degree. F.).
- (f) passing to the second cooling zone of the multi-component refrigeration system gas resulting from the evaporation of a liquefied natural gas contained in a storage vessel to produce a second liquefied natural gas stream and combining the second liquefied natural gas stream with the liquefied natural gas produced in step (e).
Dependencies are inferred from the claim text.