水素エネルギーシステムと水素の利用

抄録

At the present time most of energy is derived from fossil fuels that have a finite reserve. To conserve these fossile sources and retain the present standard of living, a sythetie fuel derived from a renewable energy source must be used. Hydrogen, a fuel that can be produced from water and is expected to emit less pollutants, appears to be the answer. In this article the prospect of hydrogen usage in future is briefly reviewed.
The combustion characteristics of hydrogen are quite different from those of methane and other gaseous hydrocarbons. A novel property of hydrogen is its ability to react with oxygen in air when in contact with a catalyst. This property allows the fabrication of catalytic burners, that is, unusual flameless heating devices.
Research on hydrogen fueld internal combustion engines has progressed at a high rate in the last several years. Extensive tests on emissions and performance carried out using an injected reciprocating engine have revealed that the hydrogen engine can attain a compression ratio of 10 to 14 and emits less NO_x than gasoline engines. The first hydrogen gas turbine was a converted J-57 Pratt and Whitney engine. The stable operation of the J-57 confirmed that conventional gas turbines could be readily adapted to hydrogen fuel. Hydrogen-oxygen fueled rocket engines have been used successfully in recent years for the earth and moon orbits.
The efficiency for a modern steam power plan is 40% at the present stage and is not expected to increase significantly as long as the present type of boiler is used. However a new type of burner operating on hydrogen and oxygen would be able to increase this efficiency to 60%. Another new technology for power generation is fuel cell. Its main advantages are high efficiency and low emission level of pollutants. Hydrogen-oxygen fuel cells have shown to function excellently in some special applications particullary in spacecraft. Efforts are being given to produce fuel cells for general use.
The industrial-chemical hydrogen usage pattern will not be altered except that the input will be pipelined hydrogen rather than natural gas or naphtha. The conventional blast furnace-converter process for iron production would be changed by appearance of cheap hydrogen.