A microwave applicator for high homogeneous high temperature heating of catalysts

Using microwave heating allows for a fast and efficient volumetric heating. For chemical reactors microwaves permit to generate the heat inside the catalyst bed directly at the location where the reaction takes place. However, compared to conventional heating it is difficult to achieve a homogeneous temperature profile. At least for large scale applicators, which are not small in all dimensions compared to the wavelength, one has standing wave patterns resulting from interference of different reflected and scattered parts of the microwave. Hence, the electromagnetic field shows a pattern consisting of field minima and maxima which result in thermal “cold” and “hot” spots. This paper describes a new scalable approach for an applicator at 2.45 GHz that achieves a homogeneous field and hence a homogeneous heating throughout the applicator.