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Ammonia has a potential as a liquid fuel for fuel cell vehicles, because it can be easily liquefied at a lower pressure and theoretically dissociated to the mixture of high-content hydrogen and nitrogen. Ammonia also has an advantage in terms of global warming because of carbon-free fuel. A fuel cell vehicle system with an ammonia onboard dissociator is proposed in this paper. The effects of temperature, pressure, and space velocity on concentrations of hydrogen and residual ammonia are investigated in the experiment. The residual ammonia separator, necessary even in the optimal condition obtained in the experiment, is designed and prepared. It is demonstrated that the fuel cell vehicle with the ammonia onboard dissociator has the potential as a new concept future vehicle.

In this paper, the authors have described a fuel-cell electric vehicle for trial purposes with the hydrogen generation system fueled with ammonia for compact vehicles. The system consists of a dissociator with Ruthenium/Alumina catalyst, a heat exchanger and an ammonia separator to remove residual ammonia. The dissociation system compactly unifies the heat exchanger and the dissociator to effectively rise the temperature of the system by installing some alumina balls just before catalyst. Therefore the system can be small in size enough to be installed on-board in the vehicle. The cruising time is about 160 minutes in the system. If the concentration of residual ammonia in the dissociated gas becomes 13 ppm or more, the residual ammonia will poison the proton exchange membrane (electrolyte) of the fuel cell, and cause the fuel cell to decrease the output.

Fuel without carbon is essential effective in preventing global warming by carbon dioxide. Hydrogen has no carbon and can be made also from the resources such as nuclear energy or renewable energies. However hydrogen is lack of portability for automobiles because of its difficulty in liquefying. Ammonia also has an advantage in terms of global warming because of carbon-free fuel. A hydrogen generation system fueled with ammonia from urea for a fuel-cell electric vehicle is described in this paper. In ammonia, the handling must be careful of safety specifically because toxicity of ammonia affects a human body and a fuel cell. On the other hand, urea can be easily changed into ammonia and dealt with safety. The license for handling of urea is unnecessary, and there are also achievements as a NOx reducing agent for diesel engines. The authors have proposed urea as a hydrogen carrier via ammonia.

Clean fuels that emit no greenhouse effect gas are requested in various fields especially of the global warming issue. The authors have proposed a hydrogen generation system using ammonia as a liquid fuel for fuel cells. The system consists of a cracking reactor, a heat exchanger and an ammonia separator to remove residual ammonia. It have been clarified that ammonia by 13 ppm or more causes an output decrease in polymer electrolyte fuel cells. In this study, the cracking efficiencies of ammonia were investigated with two kinds of and two shapes of catalysts to review the optimum conditions of the system. The conditions were decided by analyzing hydrogen concentration and residual ammonia concentration for some cracking temperatures and space velocities. At the cracking temperature of 500°C, the cracking efficiency of Ru/Al2O3 catalyst has shown sufficient results.