Optimal feed distribution in a packed-bed membrane reactor: The case of methanol oxidative dehydrogenation

For catalytic methanol oxidative dehydrogenation to formaldehyde, the packed-bed membrane reactor (PBMR) productivity is enhanced by modifying the oxygen feed distribution. An experimentally validated PBMR model is used for this purpose. The optimal membrane feed distribution is calculated by both conventional Euler−Lagrange and local optimization approaches. The latter offers a significant reduction in the number of equations to be solved, allowing one to identify the important factors influencing the optimal distribution profile. Both approaches produce identical distribution patterns and demonstrate the superiority of variable versus uniform permeability membranes. The calculated optimal permeability profiles provide higher oxygen feed at the reactor entrance, where elevated methanol concentration allows for increased reaction rate, as compared to regions downstream. The analysis confirms that the variation in the reaction rates, caused by consumption and/or dilution of the directly fed reactant (metha...