Drying solids with IR follows fundamentally different principles than drying with air. While convection brings heat to particles from the outside, infrared radiation penetrates solids and directly stimulates the molecules inside to vibrate. The key is that heat is physically defined as this very molecular vibration.
With conventional drying, a pressure differential is applied to the resins from the outside: heated, dry air with a low dew point (-20 to -40°C) is used to draw internal moisture out of the resin.
Moisture is mobilized from inside the pellet by heat and the photomolecular effect
It’s completely different with IRD drying. Here, moisture is mobilized from inside the pellet by heat and the photomolecular effect. This creates an immediate and high partial pressure gradient relative to the normal external pressure, explaining the astonishingly fast water separation.
IR radiation penetrates the pellet, driving water from the inside out to where it's significantly cooler, as the air isn't heated by infrared. Since the cool process air heats up on the pellets, there’s always a sufficient partial pressure gradient to carry away the moisture. This humid air is then conveyed outward and extracted from the rotary drum by natural convection.
B.IRD Drying - synchronous, inline process
This process completely eliminates the need to heat air, dehumidify it with desiccants, and the energy-intensive process of regenerating those desiccants - all of which are required in conventional drying.
B.IRD thus offers a significant process simplification and accelerates drying many times over. This enables inline operation where you only stage the material needed for a continuous supply to your melting unit.