Design of a chemical reactor under microwave irradiation in resonance conditions

In this paper the development of a multi-tube reactor for chemical processing, running in a microwave irradiated field, is presented. It is known that reaction processes are often improved by microwave application, but the enhancing effect is not always due only to the temperature increasing in the medium, which is produced by the radiation exposure. Thus, to study the evolution of such kind of processes needs a strict control of the irradiation conditions and the use of a proper reaction apparatus in which the interaction between radiation and irradiated materials can be precisely defined. The present work is made necessary by the need of operating with well known and reproducible experimental conditions, and the aim was to design a resonant cavity inside which the tubes with the fluid to be processed are positioned. The main choice was to operate with a resonant cavity. In fact, working in resonance conditions allows the irradiated fluid to be exposed to constant microwave power, and the field intensity and power absorption can be accurately calculated and mapped. The cavity was designed by the authors using a proper commercial software for 3D electromagnetic simulation, then the reactor operation was tested by another commercial multiphysic simulation software. The results here presented show the proper geometrical characteristics of the cavity and of the internal tubes to work at 2.45 GHz of frequency while the irradiation power can be varied depending on the needs of the process. The reactor can work with different homogeneous systems, both chemical and biological (enzyme reactions). The future development will be the construction and the real operation of the designed apparatus in order to confirm the simulation results.