Oxidation of methanol to formaldehyde in microchannel reactors: prospects and limitations

Abstract

Some features of the behavior of highly exothermic selective oxidation processes in a monolith microchannel reactor (MCR) are studied experimentally using the oxidation of methanol to formaldehyde on a Fe–Mo catalyst as an example. The process can be intensified considerably by intensively withdrawing heat from the reaction zone, operating at increased methanol concentrations of up to 12–12.5%, and using catalyst particles smaller than 0.25 mm to increase the useful product yield per unit of catalyst volume by 7–12 times, compared to multitubular reactors. The thermal operating mode of MCRs is close to the optimum theoretical regime for this class of processes, thereby making it easier to achieve high selectivity to formaldehyde. Due to the abovementioned reduction in the activity of Fe–Mo catalyst in MCRs, the prospects for using MCRs in this process must be estimated along with solving the problem of catalyst stability. The use of MCRs appears to be very promising and technologically sound when dealing with catalytic processes whose intensification is not accompanied by an appreciable reduction in activity.