Analysis Of The Potential Of Membrane Reactors For Methane Aromatization And Partial Oxidation By Dense Membranes

Membrane reactors, which are suitable to overcome limitations with respect to thermodynamic equilibrium and can integrate reaction, separation and dosing into one apparatus, are considered as attractive candidates for process intensification in the chemical and petrochemical industry. Two possible fields of application could be attractive:The first application as extractor allows to overcome limitations by chemical equilibrium and to increase the conversion of precious reactants. At the same time, the product which is extracted through the membrane could be used directly as a feedstock for other processes. The second one is the configuration as a distributor in partial oxidations of alkanes, where the desired product is generally a thermodynamically unstable intermediate. The formation of undesired side or total oxidation products reduces significantly the process efficiencies in conventional reactors.In this master thesis the application of membrane reactors by means of dense membranes are analyzed for an extractor and distributor configuration of a membrane reactor. Therefore, two examples are introduced by simulation studies in detail. The methane dehydro-aromatization (MDA) to benzene applying highly selective Palladium membranes to separate the formed hydrogen from the reaction zone, increasing the conversion of methane for process intensification, are systematically considered. The present study simulates the MDA reaction system both in a traditional fixed-bed reactor and in a membrane reactor with the reference kinetic and parameters. The simulation performances in two reactors are compared, and the influence of operating conditions, like membrane thickness, membrane diffusive coefficient, sweep feed ratio, pressure difference between tube side and shell side as well as temperature, on methane conversion, selectivity and yield of benzene are examined.As a second model, the partial oxidation of methane with a coupled steam reforming reaction is considered operating in a distributor mode by combining reaction and air separation into one setup using oxygen selective perovskite membranes. Within this way, the cost of air separation as well as the heat problem in the reaction system can be significantly lower down. An analogous simulation study is performed to evaluate operation conditions and to characterize the compatibility of reaction and trans-membrane mass transfer. The combination of experiments and simulations conducts a novel method to carry out scientific researches. Accurate simulation which can additionally help and perfect the experimental results, could predicts some tendencies of processes which probably are very difficult to examine by experiments.