Design of a radio frequency heated isothermal micro-trickle bed reactor

• The conductive losses contribute up to 30% of the total thermal losses from the reactor.
• At least three heating zones are required to obtain an isothermal length of 50 mm with a temperature non-uniformity of 2 °C.
• RF heating is able to uniformly raise the initial temperature of the entire packed bed from 20 to 80 °C in 8 s.
• The liquid hold-up of 0.88–0.92 was observed.

A near-isothermal micro-trickle bed reactor operated under radio frequency heating was developed. The reactor bed was packed with nickel ferrite micro-particles of 110 μm diameter, generating heat by the application of RF field at 180 kHz. Hydrodynamics in a co-current configuration was analysed and heat transfer rates were determined at temperature ranging from 55 to 100 °C. A multi-zone reactor bed of several heating and catalytic zones was proposed in order to achieve near-isothermal operations. Exact positioning, number of the heating zones and length of the heating zones composed of a mixture of nickel ferrite and a catalyst were determined by solving a one dimensional model of heat transfer by conduction and convection. The conductive losses contributed up to 30% in the total thermal losses from the reactor. Three heating zones were required to obtain an isothermal length of 50 mm with a temperature non-uniformity of 2 K. A good agreement between the modelling and experimental results was obtained for temperature profiles of the reactor.

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