Reused air saves energy in PET dryer

A unique airflow pattern and a new wheel dryer design on the new InteliPET drying system is made to help PET processors save on energy, maintenance, and plant space. Developed by Novatec (Baltimore, MD), the drying system is said to use 40-50% less energy than conventional systems based on dual-desiccant-bed dryers, and takes only 55-60% of the floor space used by competing wheel dryer-based systems for PET. A constant resin temperature is achieved when material exits the hopper, thanks to automated temperature and speed controls adjusting to variations in moisture level, throughput rate, and material temperature.

Compared to other wheel dryers for PET, which include an additional drying circuit, two cyclones, two low-efficiency gas heaters, and two dust collectors with cartridges that require periodic changing, the system combines a desiccant wheel dryer similar to Novatec’s NovaWheel model with a two-zone drying hopper, a 90%-efficient electric or gas-fired heater, a cyclone, and, as an option, a self-cleaning pulse-type dust collector.

The InteliPET system reuses the heated air that returns to the dryer from the hopper, splitting the stream into two and cooling the portion that passes through the desiccant wheel, while the other stream requires minimal reheating before entering the upper zone. The color touch-screen control can track readings from 11 thermocouples and automatically optimizes them without operator intervention, resulting in further energy savings.—kate.dixon@cancom.com