Drying solids with IR follows fundamentally different principles than drying with air. Whereas in the latter the heat is brought in from outside to heat the particles by convection, infrared radiation penetrates solids and directly stimulates the molecules inside to vibrate.
The trick: Heat is physically defined as precisely this molecular oscillation.
The water contained in the solid is driven from the inside to the outside by the temperature gradient – to where it is significantly cooler, because the air is not heated by infrared. Since the cool process air rather heats up at the pellet, there is always a sufficient partial pressure gradient there to remove the moisture. In addition, the high temperature gradient has a positive effect on the diffusion rate of the water in the pellet. The process air with moisture content heated at the pellet moves away from it in natural convection. In the rotary drum, this air is conveyed to the outside and discharged.
The heating of air and the subsequent dehumidification of the hot air with desiccants as well as the effort for its regeneration, as necessary in conventional drying, are thus completely eliminated.
B.IRD thus offers significant process simplification while accelerating drying many times over. This makes inline operation possible, in which only the material required for continuous supply of the melting unit is kept in stock.