Patent ID: 10330381

Abstract:
Method for the liquefaction of nitrogen using the recovery of cold energy deriving from the evaporation of liquefied natural gas comprising the steps of: sending a flow of nitrogen (100) to be liquefied to a precooler (101); sending a flow (107) of nitrogen gas exiting said precooler (101) to a heat exchanger (108) of the high pressure recirculation compressor; sending a flow (114) of nitrogen exiting said heat exchanger (108) to a high pressure recirculation compressor (115, 117); sending a flow (120) of nitrogen exiting said compressor (115, 117) to a liquefaction heat exchanger (121); sending to said liquefaction heat exchanger (121) a flow (123) of natural gas, countercurrent to the flow (120) exiting said compressor (115, 117); sending a flow (126, 150) of nitrogen exiting said liquefaction heat exchanger (121) to said heat exchanger (108) countercurrent to said flow (107) of nitrogen gas and to said flow (114) of nitrogen; sending a flow (151, 152) of nitrogen exiting said heat exchanger (108) to said precooler (101) countercurrent to said flow of nitrogen (100) to be liquefied; sending the flow (126, 130) of nitrogen exiting said liquefaction heat exchanger (121) to an expander (131); sending the flow of nitrogen exiting said expander (131) to a medium pressure separator (112) that delivers an exiting flow (132) of nitrogen.