Process and apparatus for liquefying natural gas
AssigneeThe Lummus Company
InventorLudwig Kniel
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Abstract
There is disclosed a novel process and apparatus for liquefying a hydrocarbon gas under a pressure greater than the critical pressure thereof wherein the gas is first expanded to below the critical pressure thereof to permit the facile separation of C.sub.5 and heavier hydrocarbons with the lighter components being re-pressurized to above the critical pressure thereof by such expanding gas prior to the further cooling of such re-compressed lighter components for eventual liquefaction.
Claims13
A method of liquefying natural gas having a pressure above the critical pressure thereof, which comprises:
- a. expanding said natural gas to a pressure below the critical pressure thereof;
- b. introducing the expanded gaseous stream of step (a) into a fractionating zone to remove as a liquid a C.sub.5 + hydrocarbon stream;
- c. compressing the resulting gas stream recovered from step (b) to a pressure above the critical pressure thereof;
- d. cooling the cooled gas stream of step (c);
- e. expanding said cooled gas stream from step (d) to effect liquefaction of a major portion of said cooled gas stream of step (d), and
- f. recovering said liquified major portion.
In an apparatus for liquefying natural gas having a pressure above the critical pressure thereof, which comprises:
- expander means for reducing the pressure of said natural gas below that of the critical pressure thereof;
- separation means for separating a C.sub.5 + hydrocarbon stream from said expanded natural gas to obtain a resulting gas stream of C.sub.4 or less;
- compressor means for compressing the resulting gas stream to a pressure above the critical pressure thereof;
- means for cooling said resulting gas stream;
- means for expanding said resulting gas stream to effect liquefaction of a major portion thereof;
- and
- means for recovering a major portion of said resulting gas stream.
Dependencies are inferred from the claim text.