LNG MULTI NITROGEN EXPANSION PROCESS FOR LNG PRODUCTION

摘要

The present invention relates to a natural gas liquefaction process comprising at least two nitrogen refrigerant streams. Each stream undergoes a cycle of compression, cooling, expansion and heating while each nitrogen stream is expanded to a different pressure than the rest of the at least two nitrogen streams, and the heating takes place in one or more heat exchangers. The expanded nitrogen stream is in heat exchange relationship with the one or more compressed nitrogen streams and the stream of natural gas in at least one of the one or more heat exchangers. At least one expanded nitrogen stream is compressed into a side stream in the stage of the main nitrogen compressor to pass the nitrogen compressor stage, then combining the compressed side stream with another compressed nitrogen stream.