Efficient hydrogen supply by the spray-pulse mode reactors with cyclohexane, bicyclohexyl, decalin, and their derivatives for fuel cell systems.

Abstract

Highly efficient production of hydrogen without CO₂ emission is achieved in the dehydrogenation of cyclic hydrocarbons under a non-steady spray pulse operation. Cyclohexane, methylcyclohexane, cis-decahydronaphthalene trans-decahydronaphthalene, cyclohexylbenzene, and bicyclohexyl were efficiently dehydrogenated by the Pt catalysts supported on active carbon. The rates of dehydrogenation were in the following order: cyclohexylbenzene > cyclohexane, methylcyclohexane, bicyclohexyl > cis-decahydronaphthalene, 1-methyldecahydronaphthalene > trans-decahydronaphthalene. Comparing the reactants, the highest reaction rate was observed for cyclohexylbenzene. Additionally, both in the lower temperature region (220 – 280°C) and the higher temperature region (280 – 400°C), the lowest activation energy was observed for cyclohexylbenzene (Activation energy was 63 and 29 kJ mol^-1 for 220 – 280°C and 280 – 400°C, respectively). The highest hydrogen production rate was observed for bicyclohexyl, due to its high hydrogen contents in a molecule. Comparing the cis-decalin and trans-decalin, cis- isomer showed higher reaction rate than trans- isomer, reflecting the difference of free energy (ΔG) between the product (naphthalene) and the reactants.