05390499 is referenced by 28 patents and cites 24 patents.

The present invention is directed to a process for purifying natural gas to provide a liquified natural gas product which is substantially pure methane. In the process, a natural gas feed stream is introduced into indirect countercurrent heat exchange in a first heat exchanger to cool the natural gas to below the dew point of ethane and higher hydrocarbons so as to separate the feed stream into a gas which is substantially pure methane and liquid which contains the ethane and higher hydrocarbons. The liquid/gas mixture is transferred to a separator where the gas occupies the head space of the separator and the liquid occupies the bottom of the separator. A gas fraction is removed from the top of the separator and is introduced into countercurrent heat exchange with liquid nitrogen in a second heat exchanger so as to liquefy the substantially pure methane gas. Liquid nitrogen is introduced into a third heat exchanger where the liquid nitrogen is mixed with a recycled portion of nitrogen vapor is mixed with a recycled portion of nitrogen vapor exiting from the second heat exchanger to provide a liquid nitrogen feed stream for the second heat exchanger.

Title
Process to increase natural gas methane content
Application Number
8/143924
Publication Number
5390499
Application Date
October 27, 1993
Publication Date
February 21, 1995
Inventor
Robert J Golueke
Naperville
IL, US
George D Rhoades
LaGrange
IL, US
Agent
Fitch Even Tabin & Flannery
Assignee
Liquid Carbonic Corporation
IL, US
IPC
F25J 1/00
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