Processes and systems for liquefying natural gas
AssigneeExxonMobil Upstream Research Company
InventorsRobert A. Fanning, Keenis E. Davis, James E. Kaucher, Rudolph J. Szabados
Life of this patent
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Abstract
Natural gas liquefaction systems are provided wherein dependent trains including only cryogenic heat exchanger systems are serviced by common components in the system such that individual components need not be included in each dependent train for servicing that function. Further, the common components are positioned near the LNG storage tanks which, in turn, are typically located a substantial distance from the trains. This significantly reduces capital costs and allows boil-off gas from LNG storage tanks to be used for cooling in addition to being used as a fuel gas.
Claims17
A natural gas liquefaction system comprising:
- (A) two or more dependent trains, each of said dependent trains comprising a cryogenic heat exchanger system for cooling a feed gas to a cryogenic temperature;
- (B) a common flash valve or common hydraulic turbine for reducing the pressure of the cooled feed gas to produce liquefied natural gas at substantially atmospheric pressure and a temperature of substantially −162° C. (−260° F.) (“LNG”) and a reject gas;
- (C) a common flash tank for receiving said LNG and said reject gas from said common flash valve or common hydraulic turbine and wherein said LNG and said reject gas are separated, said common flash tank having a liquid outlet and a vapor outlet;
- (D) at least one storage tank for receiving said LNG from said liquid outlet of said common flash tank;
- and
- (E) means for disposing of said reject gas received from said vapor outlet of said common flash tank.
A process for liquefying natural gas, said process comprising:
- (A) cooling a feed gas to a cryogenic temperature in two or more dependent trains, each of said dependent trains comprising a cryogenic heat exchanger system;
- (B) flowing said cooled feed gas from said two or more dependent trains to a common flash valve or common hydraulic turbine for reducing the pressure of the cooled feed gas to produce liquefied natural gas at substantially atmospheric pressure and a temperature of substantially −162° C. (−260° F.) (“LNG”) and a reject gas;
- (C) flowing said LNG and said reject gas to a common flash tank having a liquid outlet and a vapor outlet wherein said LNG and said reject gas are separated;
- (D) flowing said LNG from said liquid outlet of said common flash tank to at least one storage tank;
- and
- (E) disposing of said reject gas.
Dependencies are inferred from the claim text.