Heating characteristics of biomass and carbonaceous materials under microwave radiation

Proper understanding of microwave and material interaction is important to design effective microwave treatment system. Therefore, this paper aims to reveal the basic heating characteristics of biomass and carbonaceous materials subjected to microwave radiation at 2.45 GHz frequency. This was done in a single mode microwave system of 1 kW power capacity. The effect of microwave cavity design on the heating characteristics of oil palm shell (OPS) biomass and activated carbon was studied. A particular attention was also given to the effect of OPS biomass particle size on the temperature profiles. Biomass materials were found to be poor absorber of microwaves and the increase in temperature of biomass was found to be because of its moisture content. On the other hand, activated carbon is very good microwave absorber and can become efficient microwave susceptors for low loss materials such as biomass. Proper design of cavity is necessary to achieve high temperature values. Large size particles can be heated using microwaves but the temperature remains low which was not enough to carry out the thermo-chemical process.