Gas supply system for gas engines

Abstract

A gas supply system for dual-fuel or gas engines is adapted for integration with a boil-off gas reliquefaction plant. The system includes a cryogenic heat exchanger, a boil-off gas compressor having a boil-off gas preheater, and a nitrogen loop with a compander. The gas is in the form of liquefied natural gas from cargo tanks or condensate from the reliquefaction plant. The gas supply system also includes an evaporator (optimizer) that extracts cold duty from the gas, and/or an evaporator that is arranged in a closed loop, which includes at least one pump and a heating source for an intermediate medium used to optimize extraction of the cold duty.

1 . A gas supply system for dual-fuel or gas engines adapted for integration with a boil-off gas reliquefaction plant comprising:
 a cryogenic heat exchanger,   a boil-off gas compressor having a boil-off gas preheater, and   a nitrogen loop with a compander,   
       wherein the gas is in the form of liquefied natural gas from cargo tanks or condensate from the reliquefaction plant, and wherein the gas supply system further comprises an evaporator (optimizer) that extracts cold duty from the gas, and/or an evaporator that is arranged in a closed loop comprising at least one pump and a heating source for an intermediate medium used to optimize extraction of the cold duty. 
     
     
         2 . A gas supply system according to  claim 1 , wherein the cold duty is transferred to the reliquefaction plant upstream of the cryogenic heat exchanger. 
     
     
         3 . A gas supply system according to  claim 1 , wherein the cold duty is transferred to the reliquefaction plant in parallel with the boil-off gas preheater. 
     
     
         4 . A gas supply system according to  claim 1 , wherein the cold duty is transferred to the reliquefaction plant in parallel with the cryogenic heat exchanger or integrated into the cryogenic heat exchanger. 
     
     
         5 . A gas supply system according to  claim 1 , wherein the extracted cold duty is transferred to the reliquefaction plant using a heat exchanger arranged in a circuit connecting the optimizer to the reliquefaction plant. 
     
     
         6 . A gas supply system according to  claim 5 , wherein the liquid gas is fed by means of a low pressure pump and high pressure pump. 
     
     
         7 . A gas supply system according to  claim 1 , wherein the heating source is steam, hot water or a steamer. 
     
     
         8 . A gas supply system according to  claim 1 , wherein the intermediate medium circulated in the closed loop by means of pump(s) is a brine mixture, glycol mixture, hydrocarbon mixture or a refrigerant. 
     
     
         9 . A gas supply system according to  claim 8 , wherein there is at least one additional pump in parallel to said at least one pump. 
     
     
         10 . A gas supply system according to  claim 1 , wherein the gas is fed into the evaporator by means of at least one high pressure pump. 
     
     
         11 . A gas supply system according to  claim 9 , wherein there are:
 two pumps in parallel, wherein one pump is in operation and one pump is in stand by, or   three pumps in parallel, wherein two pumps are in operation and one pump is in stand by.