Studies On Autothermal Reforming Of Methanol In Monolithic Reactor

This paper focused on developing a fuel processing system with high efficiency. The reaction of autothermal reforming of methanol (ATR) over ZnO-Cr2O3/CeO2-ZrO2 monolithic catalyst was investigated by the experimental and theoretical studies. The problems involved in the optimization and scale-up of monolithic catalyst and reactors were discussed.Kinetics of ATR reaction over monolithic catalyst was studied by means of orthogonal experiment. A power-type rate expression was established, and its accuracy was proved by F-examination. Effects of different operating conditions on ATR reaction were investigated by analysis of variance. It was proved that the highly notable influence factors were reaction temperature and space velocity.The concentration profiles of the monolithic catalyst were measured by novel flat-bed reactor and sliced catalyst. The reaction pathways for ATR were discussed according to the results of concentration distribution. It was proved that the steam reforming of methanol happened in the whole parts of the catalyst; whereas the reactions of methanol decomposition and total oxidation of methanol mainly occured in the initial stage of the catalyst.A three-dimensional mathematical model was established to describe the ATR reaction process in monolithic reactor. Distribution of concentration in the reactor had been calculated. Effects of the mole ratio of water/methanol, oxygen/methanol, temperature and gas hourly space velocity (GHSV) on the performance of monolithic reactor had also been simulated by the model. Mathematical simulations of the concentration distribution in monolith reactor were in good agreement with the experiments. The effects of configuration parameters of monolithic reactor on reaction were investigated, such as the length of catalyst, the ratio of height/diameter of catalyst, the porosity of catalyst bed, and even the substrate materials of the catalyst. Optimal design of the monolithic reactor was achieved.The effect of different distributors in 75kW reformer on the performance of ATR system was investigated. Porous media model was chosen to simulate the temperature distribution of the scale-up reactor. The computational results indicate that this model can predict the field distribution of monolithic reactor accurately. The effect of different expanding tubes on reaction performance was also discussed. The result indicates that 120o expanding tube should be chosen preferentially.