Onboard Dehydrogenation Reactor

A research team working for Hrein Energy in Japan has succeeded in powering a vehicle with hydrogen extracted from organic hydride. The team developed a prototype on-board dehydrogenation reactor and used it in a driving test with a modified Nissan March. The team consisted of personnel from Hrein, Futaba Industrial Co., Ito Racing Service Co Ltd, and a professor emeritus from Hokkaido University.

The on-board processor uses waste heat from the catalytic converter to isolate hydrogen from organic hydride. The free hydrogen was then mixed with intake air and used to power the vehicle's 1.2L gasoline-hydrogen hybrid engine. The hydrogen constituted as much as 5 percent of the vehicle's intake air. Even with a small volume increase of hydrogen in the intake air, the vehicle's mileage rating increased by about 30 percent, due in large part because the combustibility of hydrogen exceeds that of gasoline.

The on-board processor creates free hydrogen and toluene, an aromatic hydrocarbon commonly used as an industrial solvent and in paint thinners. It is also used as an octane booster in gasoline and a fuel for high-performance racing engines.

Dehydrogenation reactors are typically large, but Hrein Energy has downsized this prototype to fit on an automobile. The reactor requires extremely high temperatures - 300° C - to operate. The operating temperature is achievable, but it creates a large energy loss. This is mitigated by the use of waste heat from the catalytic converter.

The size of the prototype reactor is an issue. While it is small enough to fit on a car, it's too small to produce a useful amount of hydrogen for long-term operations. Hrein Energy's ultimate goal is to use the technology to power fuel-cell vehicles, but waste heat production from fuel-cell vehicles is too low to provide proper temperature for the dehydrogenation reactor to work properly. As a supplemental device, however, it can increase the efficiency of a gasoline engine substantially.

Hrein Energy's next step is to develop a prototype system for a 1.5L commercial vehicle in time for the G8 Summit in Hokkaido in the summer of 2008. The company is also looking at other methods of generating and storing hydrogen as organic hydride.