Hydrogen generator, ammonia-burning internal combustion engine, and fuel cell

Abstract

A hydrogen generator that can be operated in a broad temperature range is disclosed, which comprises a first ammonia conversion part having a hydrogen-generating material which reacts with ammonia in a first temperature range so as to generate hydrogen; a second ammonia conversion part having an ammonia-decomposing catalyst which decomposes ammonia into hydrogen and nitrogen in a second temperature range; an ammonia supply part which supplies ammonia; and an ammonia supply passage which supplies ammonia from said ammonia supply part to the first and second ammonia conversion parts. The first temperature range includes temperatures lower than the second temperature range, and hydrogen is generated from ammonia by selectively using the first and second ammonia conversion parts. An ammonia-burning internal combustion engine and a fuel cell having the hydrogen generator are also disclosed.

1 . A hydrogen generator comprising;
 a first ammonia conversion part having a hydrogen-generating material which reacts with ammonia in a first temperature range so as to generate hydrogen;   a second ammonia conversion part having an ammonia-decomposing catalyst which decomposes ammonia into hydrogen and nitrogen in a second temperature range;   an ammonia supply part which supplies ammonia; and   an ammonia supply passage which supplies ammonia from said ammonia supply part to the first and second ammonia conversion parts;   wherein   the first temperature range includes temperatures lower than the second temperature range, and hydrogen is generated from ammonia by selectively using the first and second ammonia conversion parts.   
     
     
         2 . The hydrogen generator according to  claim 1 , wherein
 said hydrogen-generating material is a material which generates hydrogen by reaction with ammonia without heating under room temperature, and the ammonia-decomposing catalyst comprises a metal which can decompose ammonia into hydrogen and nitrogen only when heated from the room temperature.   
     
     
         3 . The hydrogen generator according to  claim 1 , comprising a hydrogen passage for recycling which supplies the hydrogen obtained in the second ammonia conversion part to the first ammonia conversion part. 
     
     
         4 . The hydrogen generator according to  claim 1 , comprising a heat source which provides heat to the first and/or second ammonia conversion parts. 
     
     
         5 . The hydrogen generator according to  claim 4 , wherein
 said heat source is the combustion/oxidation heat arising from the combustion/oxidation of hydrogen generated in the first and/or second ammonia conversion parts.   
     
     
         6 . The hydrogen generator according to  claim 1 , which supplies all of the hydrogen obtained in the second ammonia conversion part to the first ammonia conversion part. 
     
     
         7 . The hydrogen generator according to  claim 1 , which supplies the ammonia supplied by said ammonia supply part to the first ammonia conversion part only through the second ammonia conversion part. 
     
     
         8 . The hydrogen generator according to  claim 1 , wherein said hydrogen-generating material is a material which reacts with ammonia to generate hydrogen in the temperature range comprising, at least, 0° C. to 30° C. 
     
     
         9 . The hydrogen generator according to  claim 1 , wherein said hydrogen-generating material is a material selected from the group consisting of alkali metals, alkali earth metals, alkali metal hydrides, alkali earth metal hydrides, and a combination thereof. 
     
     
         10 . The hydrogen generator according to  claim 9 , wherein said hydrogen-generating material is a material selected from the group consisting of alkali metal hydrides, alkali earth metal hydrides, and a combination thereof. 
     
     
         11 . The hydrogen generator according to  claim 10 , wherein said hydrogen-generating material is a material selected from the group consisting of lithium hydride, sodium hydride, potassium hydride, and a combination thereof. 
     
     
         12 . The hydrogen generator according to  claim 1 , wherein said ammonia-decomposing catalyst comprises a metal selected from the group of transition metals. 
     
     
         13 . The hydrogen generator according to  claim 12 , wherein said ammonia-decomposing catalyst comprises a metal selected from the group of ruthenium, nickel, cobalt, and iron. 
     
     
         14 . An ammonia-burning internal combustion engine, having said hydrogen generator according to  claim 1  and an internal combustion engine main unit, wherein said internal combustion engine main unit generates motor power by combusting, in addition to ammonia, hydrogen which is supplied by said hydrogen generator. 
     
     
         15 . The ammonia-burning internal combustion engine according to  claim 14 , further having an exhaust gas passage for heat exchange, which provides heat to the first and/or second ammonia conversion parts by the exhaust gas from said internal combustion engine main unit. 
     
     
         16 . The ammonia-burning internal combustion engine according to  claim 15 , wherein said exhaust gas passage for heat exchange has a bypass passage, through which said exhaust gas bypasses the first ammonia conversion part. 
     
     
         17 . The ammonia-burning internal combustion engine according to  claim 14 , wherein the molar ratio of ammonia and hydrogen which are combusted in said internal combustion engine main unit ammonia: hydrogen is in the range of 100:0 to 50:50. 
     
     
         18 . A fuel cell having said hydrogen generator according to  claim 1  and a fuel cell main unit, wherein said fuel cell main unit generates electric power by oxidizing the hydrogen supplied by said hydrogen generator.