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Air Products and Chemicals, Inc.

Robert Newton Davis

Howard C Rowles

Lee J Howard

Charles L Newton

Christopher Francis Harris

Glenn E Kinard

Richard Alan Wright

A high purity methane product is recovered from a feed gas mixture containing methane and one or more hydrocarbons heavier than methane by cooling, condensing, and rectifying the feed in a dephlegmator. The high purity methane product, containing at least 98 mole % methane, can be liquefied and stored for use as a fuel for internal combustion engines. A hydrocarbon product containing components heavier than methane is also recovered. Methane recovery and C.sub.2.sup.+ hydrocarbon product purity can be improved by the use of a combined stripping heat exchanger and feed gas cooler. External refrigeration is utilized and can be supplemented in part by autorefrigeration provided by vaporizing dephlegmator liquid.

Production of refrigerated liquid methane

The present invention is an improvement to a liquefaction process for natural gas, wherein refrigeration for the liquefaction process is provided by two closed-loop refrigeration cycles. The first or low level refrigeration cycle uses either a mixed refrigerant or a single component refrigerant as the heat pump fluid, and the second or high level refrigerant uses a mixed (multicomponent) refrigerant as the heat pump fluid. In the liquefaction process the second or high level refrigeration cycle cools the low level heat pump fluid. The low level refrigeration cycle cools and liquefies the cooled natural gas feed. The improvement to the process is the use of an absorption refrigeration cycle to precool the natural gas feed, the low level heat pump fluid, the high level heat pump fluid and, if required, the deep flash recycle. Heat to drive the absorption refrigeration cycle is provided by the exhaust gas from one or more drives for the compressors in the process.

Natural gas liquefaction process using low level high level and

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Breinigsville, PA, United States of America

Robert Newton Davis