INTEGRATED NITROGEN REMOVAL IN THE PRODUCTION OF LIQUID NATURAL GAS USING AN INTERMEDIATE SEPARATION OF THE SOURCE GAS

摘要

1. A method of producing nitrogen-depleted commercial LNG, comprising: (a) introducing a feed of natural gas into the hot end of the main heat exchanger, cooling and at least partially liquefying the feed of natural gas and discharging the cooled and at least partially liquefied stream from the intermediate position of the main a heat exchanger; (b) expanding, partially evaporating and separating the cooled and at least partially liquefied stream to form a vapor stream of a nitrogen-rich natural gas and a liquid stream depleted of natural gas nitrogen; (c) re-introducing separately the specified steam stream and liquid stream into the intermediate position of the main heat exchanger, additional parallel cooling of the steam and liquid streams, the liquid stream is further cooled to form the first LNG stream, and the steam stream is further cooled and at least partially liquefied to form a first stream of at least partially liquefied nitrogen-rich natural gas and the output of the first LNG stream and the first stream at least a measure of partially liquefied nitrogen-enriched natural gas from the cold end of the main heat exchanger; (d) expanding, partially evaporating and separating a first stream of at least partially liquefied nitrogen-enriched natural gas to form a nitrogen-enriched steam product and a second LNG stream; and (e) expansion, partial evaporation and separation of the second LNG stream to produce depleted nitrogen of commercial LNG and vapors of nitrogen-enriched natural gas. 2. The method of claim 1, wherein step (e) further comprises forming