Manufacturers that process rice and other grains for use in foods, pharmaceuticals or beauty products, and companies that process herbs (primarily for use in supplements), animal feeds, wood fines or dry chemicals must all reduce product moisture to preserve product quality. The challenge is to do so quickly, without generating regulated emissions. With fragile materials, care must be taken to avoid material-handling methods or temperatures that compromise yields or cause stress cracking or breakage.

One method that has long had the potential for satisfying these requirements is infrared energy. Until recently, however, infrared was unable to achieve the combination of low temperature, high throughput and product damage prevention that was required for commercial success.

With support from the U.S. Department of Energy, a hybrid infrared technology was developed by Catalytic Drying Technologies LLC., Independence, Kan., that met all of the objectives. Tests conducted over a 42-month period showed the technology capable of reducing the moisture content of a variety of products from as high as 60 percent, to as low as 3.4 percent.

One company that is benefiting from Catalytic's technology is Potlatch Corp., Spokane, Wash. Potlatch asked Catalytic Drying Technologies to evaluate the system's effectiveness on oriented strand board (OSB) flakes. With DOE approval, testing began on OSB material. The Institute of Paper Science and Technology (IPST) conducted the VOC evaluation for these tests.

The tests demonstrated significant benefits from moisture removal using catalytic infrared technology. Advantages include the ability to combine flakes and fines for use in the product, the prevention of material curling, and the ability to dry consistently to below 8 percent moisture content. Other benefits include the ability to dry without generating VOCs, CO and NO.

Key to the performance of the catalytic dryer is the combining of infrared energy with a handling method that induces the material itself to maximize infrared action. The system also was engineered to efficiently remove moisture that is liberated in the dryer. It is zoned for greatest operational flexibility.