| 摘要 |
A method and apparatus for conditioning imported liquefied natural gas to conform to a particular pipeline heating value specification and recovery of liquefied petroleum gas or natural gas liquids from liquefied natural gas are disclosed. An input stream containing liquefied natural gas is split into a direct stream and a bypass stream. The direct stream is heated in a cross-exchanger to produce a heated rich liquefied natural gas stream, which is split into a primary column feed and a secondary column feed. At least a major portion of the secondary column feed is vaporized to produce a vaporized secondary column feed, which is expanded in an expander to produce a vaporized and expanded secondary column feed. A top feed, the primary column feed, and the vaporized and expanded secondary column feed are fractionated to produce an overhead product stream and a bottom product stream. The overhead product stream is compressed in a compressor coupled to the expander. At least a major portion of the compressed overhead product stream is condensed by cooling in the cross-exchanger to produce a compressed and condensed overhead product stream. A reflux stream of at least one of the compressed and condensed overhead product stream or an output stream is directed to a top of the fractionation unit as the top feed. The bypass stream is mixed with a balance stream of the compressed and condensed overhead product stream to produce the output stream, which is vaporized to produce a conditioned natural gas product.
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