Systems and Methods for Natural Gas Liquefaction Capacity Augmentation

Abstract

Systems and methods for natural gas liquefaction capacity augmentation using supplemental cooling systems and methods to improve the efficiency of a liquefaction cycle for producing liquefied natural gas (LNG).

1 . A supplemental cooling system for chilling a process feed gas, which comprises:
 a liquid chiller ejector system;   a steam input line in fluid communication with the liquid chiller ejector system; and   a chilled liquid line wherein each end of the chilled liquid line is in fluid communication with the liquid chiller ejector system.   
     
     
         2 . The system of  claim 1 , further comprising a heat exchanger enclosing a portion of a process feed gas line and a portion of the chilled liquid line, wherein the process feed gas line and the chilled liquid line are positioned in sufficient proximity to each other in the heat exchanger to affect heat transfer between the process feed gas when it passes through the process feed gas line and a chilled liquid when it passes through the chilled liquid line. 
     
     
         3 . The system of  claim 2 , wherein the heat exchanger encloses a portion of a refrigeration intercooler line and a portion of a refrigeration aftercooler line, the refrigeration intercooler line and the refrigeration aftercooler line each positioned in sufficient proximity to the process feed gas line and the chilled liquid line in the heat exchanger to affect heat transfer between the process feed gas when it passes through the process feed gas line, the chilled liquid when it passes through the chilled liquid line, a refrigeration intercooler when it passes through the refrigeration intercooler line and a refrigeration aftercooler when it passes through the refrigeration aftercooler line. 
     
     
         4 . The system of  claim 1 , further comprising a heat exchanger enclosing a portion of a single mixed refrigerant line and a portion of the chilled liquid line, wherein the single mixed refrigerant line and the chilled liquid line are positioned in sufficient proximity to each other in the heat exchanger to effect heat transfer between a single mixed refrigerant when it passes through the single mixed refrigerant line and a chilled liquid when it passes through the chilled liquid line. 
     
     
         5 . The system of  claim 1 , further comprising a gas turbine engine with an inlet air passage and enclosing a portion of the chilled liquid line, wherein the inlet air passage and the chilled liquid line are positioned in sufficient proximity to each other in the gas turbine engine to affect heat transfer between inlet air when it passes through the inlet air passage and a chilled liquid when it passes through the chilled liquid line. 
     
     
         6 . The system of  claim 1 , wherein the liquid chiller ejector system comprises a steam ejector, a flash drum and a condenser. 
     
     
         7 . The system of  claim 6 , wherein the steam ejector, the flash drum and the condenser are in fluid communication with each other, the steam ejector is connected to the steam input line and the flash drum is connected to each end of the chilled liquid line. 
     
     
         8 . A method for chilling a process feed gas using a supplemental cooling system, which comprises:
 chilling a liquid to a temperature of about 8° C. to about 0° C. in the supplemental cooling system;   circulating the chilled liquid through a chilled liquid line, wherein each end of the chilled liquid line is in fluid communication with the supplemental cooling system;   chilling the process feed gas in a heat exchanger as the process feed gas passes through a portion of a process feed gas line in the heat exchanger next to a portion of the chilled liquid line in the heat exchanger; and   sending the chilled process feed gas to a liquefaction unit.   
     
     
         9 . The method of  claim 8 , wherein the process feed gas line and the chilled liquid line are positioned in sufficient proximity to each other in the heat exchanger to affect heat transfer between the process feed gas when it passes through the process feed gas line and the chilled liquid when it passes through the chilled liquid line. 
     
     
         10 . The method of  claim 8 , wherein the liquid is chilled using steam produced by one or more heat recovery generators. 
     
     
         11 . The method of  claim 10 , wherein the one or more heat recovery generators recover waste heat from a gas turbine engine. 
     
     
         12 . The method of  claim 8 , wherein the process feed gas is chilled to a temperature of about 12° C. to about 15° C. 
     
     
         13 . The method of  claim 8 , further comprising chilling inlet air in a gas turbine engine as the inlet air passes through an inlet air passage in the gas turbine engine next to a portion of the chilled liquid line in the gas turbine engine. 
     
     
         14 . The method of  claim 13 , wherein the inlet air passage and the chilled liquid line are position in sufficient proximity to each other in the gas turbine engine to affect heat transfer between the inlet air when it passes through the inlet air passage and the chilled liquid when it passes through the chilled liquid line. 
     
     
         15 . A method for chilling a process feed gas using a supplemental cooling system, which comprises:
 chilling a liquid to a temperature of about 8° C. to about 0° C.;   sending the chilled liquid to a process vessel; and   chilling the process feed gas in a heat exchanger positioned within the process vessel as the process feed gas passes through a portion of a process feed gas line in the heat exchanger next to a portion of a chilled liquid line in the heat exchanger.   
     
     
         16 . The method of  claim 15 , wherein the process feed gas is chilled to a temperature of about 12° C. to about 15° C.