(621s) The Use of Induction Heating for on-Demand Desorption and Catalytic Reaction

Ferromagnetic materials (like Fe or Fe₂O₃) are known to generate heat when exposed to an alternating magnetic field in the radiofrequency range (RF). This property can be utilised for indirect or remote heating of a composite medium, where one component is magnetic.

Here we report two sets of experiments of utilising RF magnetic field for i) desorption from composite pellets, and ii) endothermic reaction in a composite porous medium.  By adding iron microparticles to the composite adsorbent or catalyst pellets and consequently exposing them to RF field, we were able to control the temperature and consequently the progress of desorption and turning on/off the autocatalytic reaction.

The desorption was investigated in three systems: water-zeolite, water-silica and toluene-activated carbon. The heating properties of the composite pellets and the rate of desorption were investigated with respect to the their composition and magnetic field strength. The progress of desorption was evaluated from the energy balance by comparing the pellet heating progress with and without adsorbed compound. Pellets internal structure was investigated by scanning electrone microscopy and both pellets pores diamenter and volume were analysed by means of mercury porosimetry.

The dehydratation of ethanol on alumina  forming ethene was chosen as a model endothermic, temperature controlled catalytic reaction. The reaction was investigated in a plug-flow reactor filled with the catalyst in a form of a rectangular pellets with approximal dimension of 2x2x5mm. The progress of the reaction was tracked by a volumetric measurement of the evolving ethylene gas. The rate of the reaction and the conversion factor was investigated for different i) ethanol gass partial pressure (above boiling point of athanol) and ii) temperature of the catalyst, where the catalyst temperature was controlled by RF heating.