Hydrogen fuel vaporiser

Abstract

A hydrogen fuel vaporiser ( 218 ) is shown for vaporising cryogenically-stored hydrogen fuel prior to injection into a gas turbine engine. The vaporiser ( 218 ) comprises a fuel offtake ( 301 ) configured and arranged to divert a portion of hydrogen fuel from a main fuel conduit ( 217 ), a burner ( 303 ) configured and arranged to burn the portion of hydrogen fuel diverted from the main fuel conduit ( 217 ), and a heat exchanger configured and arranged to transfer heat produced by the burner to hydrogen fuel in the main fuel conduit ( 217 ).

1 . A hydrogen fuel vaporiser for vaporising cryogenically-stored hydrogen fuel prior to injection into a gas turbine engine, comprising:
 a fuel offtake configured and arranged to divert a portion of hydrogen fuel from a main fuel conduit;   a burner configured and arranged to burn the portion of hydrogen fuel diverted from the main fuel conduit; and   a heat exchanger configured and arranged to transfer heat produced by the burner to hydrogen fuel in the main fuel conduit.   
     
     
         2 . The hydrogen fuel vaporiser of  claim 1 , in which the burner comprises the heat exchanger. 
     
     
         3 . The hydrogen fuel vaporiser of  claim 1 , the burner and the heat exchanger are separate units. 
     
     
         4 . The hydrogen fuel vaporiser of  claim 1 , in which the heat exchanger comprises a first pass for hydrogen fuel and a second pass for exhaust from the burner. 
     
     
         5 . The hydrogen fuel vaporiser of  claim 4 , the first pass is the main fuel conduit, and the second pass surrounds the main fuel conduit. 
     
     
         6 . The hydrogen fuel vaporiser of  claim 4 , in which the first pass comprises a plurality of fuel passages for hydrogen fuel received from the main fuel conduit, and the second pass comprises a plurality of exhaust passages for exhaust received from the burner. 
     
     
         7 . The hydrogen fuel vaporiser of  claim 1 , further comprising a pre-mixer configured and arranged to mix the portion of hydrogen fuel diverted from the main fuel conduit and a supply of air prior to admission into the burner. 
     
     
         8 . The hydrogen fuel vaporiser of  claim 1 , further comprising a pre-heater for initial heating of liquid hydrogen when insufficient heat is available to boil the portion of hydrogen fuel diverted from the main fuel conduit. 
     
     
         9 . The hydrogen fuel vaporiser of  claim 8  in which the pre-heater comprises an electric heating element. 
     
     
         10 . The hydrogen fuel vaporiser of  claim 8 , in which the pre-heater comprises a boil volume. 
     
     
         11 . A hydrogen-fueled gas turbine engine comprising:
 a fuel pump configured to pump cryogenically-stored hydrogen fuel through a main fuel conduit;   a hydrogen fuel vaporiser having a fuel offtake to divert a portion of hydrogen fuel from a main fuel conduit, a burner to burn the portion of hydrogen fuel diverted from the main fuel conduit, and a heat exchanger to transfer heat produced by the burner to hydrogen fuel in the main fuel conduit, thereby vaporising it; and   a fuel injection system configured to receive vaporised hydrogen fuel and inject it into a combustor.   
     
     
         12 . The hydrogen-fueled gas turbine engine of  claim 11 , in which the hydrogen fuel vaporiser further comprises a pre-mixer configured to mix air with the portion of hydrogen fuel diverted from the main fuel conduit prior to admission into the burner. 
     
     
         13 . The hydrogen-fueled gas turbine engine of  claim 11 , in which the gas turbine engine comprises:
 a compressor for compressing inlet air for supply to the combustor; and   a bleed air system configured to bleed compressed air from the compressor and supply it to the burner to burn with the portion of hydrogen fuel diverted from the main fuel conduit.   
     
     
         14 . The hydrogen-fueled gas turbine engine of  claim 11 , in which the gas turbine engine further comprises a fuel recuperator between the hydrogen fuel vaporiser and the fuel injection system for heating the hydrogen fuel by exhaust from the gas turbine engine. 
     
     
         15 . The hydrogen-fueled gas turbine engine of  claim 14 , further comprising a fuel turbine for receiving heated hydrogen fuel from the recuperator to drive a load. 
     
     
         16 . A method of delivering cryogenically-stored hydrogen fuel to a gas turbine engine, comprising:
 pumping the hydrogen fuel from a cryogenic storage system through a main fuel conduit;   diverting a portion of hydrogen fuel from the main fuel conduit;   burning the portion of hydrogen fuel diverted from the main fuel conduit in a burner;   vaporising the hydrogen fuel in the main fuel conduit by exchanging heat produced by the burner thereto in a heat exchanger.   
     
     
         17 . The method of  claim 16 , further comprising pre-heating the portion of hydrogen fuel diverted from the main fuel conduit to boil it prior to the burning step, optionally wherein the pre-heating comprises boiling it with an electrical heating element, or in a boil volume. 
     
     
         18 . The method of  claim 16 , further comprising pre-mixing air with the portion of hydrogen fuel diverted from the main fuel conduit prior to the burning step. 
     
     
         19 . The method of  claim 16 , further comprising bleeding compressed air from a compressor of the gas turbine engine and supplying the compressed air to the burner to burn with the portion of hydrogen fuel diverted from the main fuel conduit. 
     
     
         20 . The method of  claim 16 , further comprising recuperating exhaust heat from the gas turbine into the hydrogen fuel after the vaporising step and before the injecting step.