Carbon-free fuel is effective in preventing global warming. Hydrogen has no carbon and can be made also from nuclear energy or reproducible energies other than fossil fuels. However, hydrogen lacks portability because of its difficulty in liquefying, but ammonia can easily be liquefied at a room temperature and dissociated into high-content hydrogen and nitrogen using a suitable catalyst. An ammonia dissociation system for fuel cells is proposed in this paper. The residual ammonia by 13 ppm or more in the dissociated gas (H 2 +N 2 ) causes a decrease in the output of fuel cells. To separate residual ammonia, it should be sent to an ammonia separator and then to an ammonia distiller. In the experiment, the authors examine the concentrations of ammonia after dissociation at various temperatures, pressures and space velocities. The ammonia separator uses the fact that ammonia dissolves well in water. Then the ammonia water is distilled in the distiller. Thereby, the authors have proposed an ammonia circulation system that is a clean energy system.
Jet fuel production from long-chain n-paraffins obtained by hydroprocessing of vegetable oils and animal fats has attracted immense interest. Isomerization and mild cracking are essential to transform long-chain n-paraffins with chain lengths of 16, 18, or 20 into bio-jet fuels consisting of isoparaffins with carbon numbers ranging from 9 to 15. Bifunctional catalysts consisting of noble metal and metal oxide support with solid acid, such as Pt loaded zeolite, are promising for hydroisomerization and cracking reactions. However, the effect of the specific properties of Pt loaded zeolite on the hydroisomerization and simultaneous mild cracking activity are not understood. We investigated the hydroisomerization and cracking of n-paraffins into isoparaffins with shorter chain length by 3-5 carbons over Pt loaded zeolite. n-Decane was first used as a reactant to simplify the reactions, and the effects of zeolite framework structure, solid acid sites, and Pt loading were investigated. 0.5 wt% Pt loaded MFI with Si/Al of 200 was found to maximize the targeted isoparaffin yield. Further modification of the optimized catalyst was performed for isoparaffin production from n-dodecane. Addition of MgO to the catalyst successfully suppressed overcracking and improved the desired isoparaffin yield.
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