Kinetics And Reactor Simulation Of Decalin Dehydrogenation

Decalin, a representative liquid organic hydride, is a promising candidate for hydrogen carrier. Hydrogen stored in decalin can be released through catalytic dehydrogenation. We investigated the dehydrogenation of liquid decalin for hydrogen production, about 47% decalin conversion was achieved over a Pt catalyst supported on granular activated carbon; production distribution showed that decalin dehydrogenation was a parallel reaction with the formation of naphthalene and tetralin respectively. The kinetic experiment was carried out in a high pressure autoclave, under the conditions of 290-335℃,0.7-1.3 MPa and stirring speed of 1000 r/min. An apparent kinetic model was used for the description of the reaction, the kinetic parameters were obtained by nonlinear fitting of the experimental data. The acquired apparent activation energy of naphthalene and tetralin formation was 116.27 kJ/mol and 114.38 kJ/mol respectively. The results of statistic test showed that the rate equation was rational and reliable. Besides, a power law kinetic model was used for the description of hydrogen releasing via catalytic gas-phase decalin dehydrogenation. The kinetic parameters were obtained by nonlinear least squares fitting of the experimental data; the acquired reaction order related to decalin was 0.585,with an activation energy of 59.012 kJ/mol.Based on the kinetic analysis, we designed a batch autoclave liquid phase dehydrogenation reactor and concentric tube gas phase dehydrogenation reactor, both of which were heated by catalytic combustion of hydrogen. The reactor mathematical model was established respectively, and the model was solved for understanding of the temperature distribution and concentration distribution in the reactor, then, the influence of operating conditions on reactor performance was analysed. Finally, two dehydrogenation reactors with certain hydrogen production rate were designed. We also established a gas phase dehydrogenation process and carried out the process simulation and compared the gas phase dehydrogenation system with liquid phase dehydrogenation system.