LNG boiloff gas recondensation configurations and methods
AssigneeFluor Technologies Corporation
InventorJohn Mak
Life of this patent
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Abstract
Systems and methods for optimizing the recondensation of boiloff gas in liquid natural gas storage tanks are presented. In especially preferred aspects of the inventive subject matter, BOG from a storage tank is condensed using refrigeration content of a portion of LNG sendout in a direct or indirect manner, and the BOG condensate and LNG sendout portion are combined to form a subcooled stream that is then combined with the balance of the LNG sendout, to be fed to a high pressure pump. Contemplated recondensation operations advantageously occur without using otherwise needed large volume recondensers. Moreover, the condensing and subcooling operations are decoupled from the LNG sendout rate.
Claims14
A method of producing a combined sendout stream of liquid natural gas (LNG) and boiloff gas (BOG) condensate from a storage tank configured to provide a BOG stream and a sendout LNG stream, comprising:
- compressing the BOG stream to thereby produce compressed BOG;
- condensing, in a recondenser, at least a first portion of the compressed BOG using a first portion of the LNG sendout stream to thereby produce an intermediate BOG/LNG stream at a first pressure;
- passing the intermediate BOG/LNG stream from the recondenser to a surge tank, wherein the surge tank is a separate vessel from the recondenser;
- pumping the intermediate BOG/LNG stream from the surge tank with a pump to provide a subcooled BOG/LNG stream at a second pressure;
- combining the subcooled BOG/LNG stream with a second portion of the LNG sendout stream to thereby produce a combined subcooled sendout stream;
- feeding the combined subcooled sendout stream to a high pressure pump;
- pumping the combined subcooled sendout stream with the high pressure pump to form a high pressure LNG sendout stream;
- and
- recirculating a portion of the high pressure LNG sendout stream to the surge tank.
Dependencies are inferred from the claim text.