Method For Vaporizing Cryogenic Liquid Through Heat Exchange Using Calorigenic Fluid

Abstract

A method of vaporizing cryogenic liquid, for example liquefied natural gas, by heat exchange with a calorigenic fluid, for example gaseous nitrogen is provided.

1 - 10 . (canceled) 
     
     
         11 . A method for heating up a first fluid by heat exchange with a second fluid in a plate and fin heat exchanger in which the first fluid is heated up in a first series of separated passages and the second fluid is cooled down in a second series of separated passages, comprising:
 separating each passage of the first series from the nearest passage of the second series by an auxiliary passage containing fins in which an inert gas circulates.   
     
     
         12 . The method of  claim 11 , wherein the first fluid consists of liquefied natural gas which is heated in the first series of separated passages. 
     
     
         13 . The method of  claim 11 , wherein the first fluid consists of liquefied natural gas which is vaporized in the first series of separated passages. 
     
     
         14 . The method of  claim 11 , wherein the second fluid consists of gaseous nitrogen which cools in the second series of separated passages. 
     
     
         15 . The method of  claim 11 , wherein the second fluid consists of gaseous nitrogen which liquefies in the second series of separated passages. 
     
     
         16 . The method of  claim 11 , wherein the inert gas is at a pressure at least 0.1 bar higher than those of the first fluid and of the second fluid. 
     
     
         17 . The method of  claim 11 , wherein the inert gas is at a pressure at least 0.5 bar higher than those of the first fluid and of the second fluid. 
     
     
         18 . The method of  claim 11 , wherein the inert gas is at a pressure at least 0.1 bar lower than those of the first fluid and of the second fluid. 
     
     
         19 . The method of  claim 11 , wherein the inert gas is at a pressure at least 0.5 bar lower than those of the first fluid and of the second fluid. 
     
     
         20 . The method of  claim 11 , wherein the inert gas is gaseous nitrogen. 
     
     
         21 . The method of  claim 11 , wherein the inert gas sent into at least certain auxiliary passages is then sent to the atmosphere. 
     
     
         22 . The method of  claim 11 , wherein the inert gas sent into at least certain auxiliary passages is then sent to a flare. 
     
     
         23 . The method of  claim 11 , wherein at least one inlet and/or outlet box of one of the first and second fluids is separated from the passages in which the other of the first and second fluids circulates by means of a double bar system. 
     
     
         24 . The method of  claim 23 , wherein said double bar system comprises bars separated by a dead zone. 
     
     
         25 . The method of  claim 11 , wherein the first fluid is heated up at a pressure of at least 60 bar abs. 
     
     
         26 . A method of starting a plate and fin heat exchanger in which, at full capacity, a first fluid is heated up by heat exchange with a second fluid in a plate and fin heat exchanger, the first fluid being heated up in a first series of separated passages and the second fluid being cooled down in a second series of separated passages, comprising
 separating each passage of the first series from the nearest passage of the second series by an auxiliary passage containing fins and in which during start-up an inert gas at a temperature lower than ambient temperature, possibly at cryogenic temperature, is sent into at least one auxiliary passage in order to get down to temperature more swiftly.   
     
     
         27 . The method of  claim 26 , wherein during start-up said inert gas has a cryogenic temperature.