Design of a microstructured reactor with integrated heat-exchanger for optimum performance of a highly exothermic reaction

The activity and the heat transfer characteristics of several microstructur ed reactors have been compared in the ammonia oxidation on Pt catalyst. The main parameters which influence reactor performance are catalyst loading, temperature, and the intrinsic conductivity of the reactor material, In cas e of aluminum as a reactor material, hot spot temperatures were within 5 de greesC at full conversion of 6 vol.% NH3. Temperature gradients were consid erably larger when the microreactor was made from pure platinum due to the smaller intrinsic material conductivity. As a result, the maximum N2O selec tivity was by 20% lower than in the case of the aluminum-based reactor due to considerable differences in the selectivities between the central and wa ll channels. Experimental data obtained on the above microreactors were use d to design an externally cooled cross flow microreactor/heat-exchanger ope rating at almost isothermal conditions even with a reaction mixture corresp onding to an adiabatic temperature rise of about 1400 degreesC. Such system can provide new opportunities for improvement of existing gas/solid cataly tic processes with strongly exothermic reactions. (C) 2001 Elsevier Science B.V. All rights reserved.