Natural gas liquefaction apparatus

Abstract

Provided is a natural gas liquefaction apparatus including: a cryogenic heat exchanger through which natural gas passes through and is liquefied into liquefied natural gas (LNG) through heat exchange with a first refrigerant and a second refrigerant; a first refrigerant cycle through which the first refrigerant circulates, which has some paths passing through the cryogenic heat exchanger to perform heat exchange, and which has a path of the first refrigerant divided into a plurality of paths after performing heat exchange at the cryogenic heat exchanger and performs expansion and pre-compression of the first refrigerant; and a second refrigerant cycle through which the second refrigerant circulates and which has some paths passing though the cryogenic heat exchanger.

1 . A natural gas liquefaction apparatus comprising:
 a cryogenic heat exchanger through which natural gas passes through and is liquefied into liquefied natural gas through heat exchange with a first refrigerant and a second refrigerant;   a first refrigerant cycle through which the first refrigerant circulates, which has some paths passing through the cryogenic heat exchanger to perform heat exchange, and which has a path of the first refrigerant divided into a plurality of paths after performing heat exchange at the cryogenic heat exchanger, and performs expansion and pre-compression of the first refrigerant; and   a second refrigerant cycle through which the second refrigerant circulates and which has some paths passing though the cryogenic heat exchanger.   
     
     
         2 . The natural gas liquefaction apparatus of  claim 1 , wherein the first refrigerant cycle comprises:
 a first refrigerant first compression part provided upstream of the cryogenic heat exchanger and configured to compress the first refrigerant to a high pressure;   a first refrigerant first turbo expander comprising a first refrigerant first expansion part provided downstream of the cryogenic heat exchanger and configured to expand the first flow among the two divided flows of the first refrigerant having passed through the cryogenic heat exchanger, and a first refrigerant first pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant first expansion part and has passed through the cryogenic heat exchanger again; and   a first refrigerant second turbo expander comprising a first refrigerant second expansion part provided downstream of the cryogenic heat exchanger and configured to expand the second flow among the two divided flows of the first refrigerant having passed through the cryogenic heat exchanger, and a first refrigerant second pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant second expansion part and has passed through the cryogenic heat exchanger again.   
     
     
         3 . The natural gas liquefaction apparatus of  claim 1 , wherein the first refrigerant cycle comprises:
 a first refrigerant first compression part provided upstream of the cryogenic heat exchanger and configured to compress the first refrigerant to a high pressure;   a first refrigerant first turbo expander comprising a first refrigerant first expansion part provided downstream of the cryogenic heat exchanger and configured to expand the first flow among the three divided flows of the first refrigerant having passed through the cryogenic heat exchanger, and a first refrigerant first pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant first expansion part and has passed through the cryogenic heat exchanger again;   a first refrigerant second turbo expander comprising a first refrigerant second expansion part provided downstream of the cryogenic heat exchanger and configured to expand the second flow among the three divided flows of the first refrigerant having passed through the cryogenic heat exchanger, and a first refrigerant second pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant second expansion part and has passed through the cryogenic heat exchanger again; and   a first refrigerant third turbo expander comprising a first refrigerant third expansion part provided downstream of the cryogenic heat exchanger and configured to expand the third flow among the three divided flows of the first refrigerant having passed through the cryogenic heat exchanger, and a first refrigerant third pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant third expansion part and has passed through the cryogenic heat exchanger again.   
     
     
         4 . The natural gas liquefaction apparatus of  claim 2  or  claim 3 , wherein first refrigerant first compression part is provided in plurality. 
     
     
         5 . The natural gas liquefaction apparatus of  claim 1 , wherein the second refrigerant cycle comprises:
 a second refrigerant compression part provided upstream of the cryogenic heat exchanger and configured to compress the second refrigerant to a high pressure; and   a second refrigerant turbo expander comprising a second refrigerant expansion part provided downstream of the cryogenic heat exchanger and configured to expand the second refrigerant having passed through the cryogenic heat exchanger, and a second refrigerant pre-compression part configured to pre-compress the second refrigerant which has been expanded by the second refrigerant expansion part and has passed through the cryogenic heat exchanger again.