First Scientific Comparison of Resin Dryers Shows Why Industry Will Shift to New, More Efficient Drying Systems

As Only Supplier of All Dryer Types, NOVATEC Predicts Major Move from Twin-Bed to Wheel Dryers, Plus Strong Growth for Vacuum and Membrane Systems

BALTIMORE, MD, U.S.A., June 18, 2007: Building on its position as the only manufacturer of every type of resin drying system used in the plastics industry, NOVATEC, Inc. recently began scientifically rigorous comparative testing of its drying technologies and is today disclosing the initial conclusions based on the first test results.

"While dual-bed or 'twin-tower' desiccant dryers like our NDB series have set the industry standard for drying efficiency for many years, our initial data lead us to expect that self-regenerating wheel systems like our NovaWheel(TM) dryer will dominate future sales of new desiccant systems, particularly in the mid- to high-throughput range," said sales manager Mark Haynie. "The tests also reveal economic and productivity advantages over desiccant dryers that promise strong growth for membrane and vacuum systems, neither of which was available to U.S. plastics processors before the year 2000."

The data cited by Haynie were compiled in the recently completed Drying Technology Center at NOVATEC headquarters in Baltimore, where lab manager Jim Brown operates actual production units of NOVATEC drying systems. The tests were the first systematic development of hard data for comparing drying systems of different types, according to Brown.

"This is just the beginning of a long-range program to test every one of our dryer models, examining all resins subject to drying and all performance criteria relevant to the productivity and profitability of our customers," said Conrad M. Bessemer, NOVATEC president and CEO. "Because we offer every dryer type, we can recommend systems strictly according to what the customer needs, not what we happen to have on hand to sell. By putting our recommendations on a firm scientific basis, the Drying Technology Center will help our customers select the best possible system for the job."

Tests Reveal Cost-Performance Advantages of Three New Drying Systems

Even as new types of dryer have entered the marketplace, NOVATEC remains committed to supplying its dual-bed desiccant dryer and other established product, according to Haynie. "Dual-beds have been the industry workhorse and are an integral part of the operations of a very large number of customers," he noted. "These are rugged, reliable systems with a long track record, and we expect that a significant number of processors will continue ordering dual-bed systems as their operations expand. Nevertheless, a shift toward alternative systems is already under way in the industry, and, based on our initial test data, that shift will accelerate."

The NOVATEC Drying Technology Center compared the company's NDB dual-bed desiccant dryer with three new types of dryer. [A fourth new NOVATEC system, the IRD infrared crystallizer/dryer for PET, is not directly comparable with the dual-bed dryer, though the lab has also subjected the IRD system to systematic testing.] The tests focused on two parameters: moisture removal over time and energy consumption. The resins used were ABS and polycarbonate (PC). Test results appear in Tables A and B. An overview of NOVATEC dryer products appears in Table C.

o NovaWheel(TM). This rotating-wheel dryer continuously puts dry desiccant into service while regenerating saturated desiccant in the same rotational cycle. In the NOVATEC tests, the energy cost per hour for the wheel dryer was 35% less than the dual-bed dryer for ABS and 14% less for PC. Times required to reach acceptable moisture levels were comparable. "Because the wheel dryer uses substantially less energy than a twin-bed desiccant system, dries more consistently, and is simpler and more compact, we expect it to take the place of the older dryer for applications involving throughputs of 225 lb. [100 kg] per hour or greater," Haynie said.

o NovaVac II(TM). This vacuum dryer pulls moisture from the resin pellets, eliminating desiccant altogether. The test measuring moisture removal over time confirmed the initial claim for vacuum dryers that drying is complete within 40 minutes. The dual-bed desiccant dryer required twice the time for PC and three times the time for ABS to reduce moisture to comparable levels. Energy costs per hour for the vacuum dryer were 29% and 35% less for ABS and PC, respectively, than the dual-bed dryer; and while the NovaWheel dryer actually exhibited lower energy cost than the NovaVac II for ABS, the reverse was true for PC, as the NovaVac II cost was 24% lower. "For high-temperature materials, the vacuum dryer is more energy efficient than all three other dryers, and its drying speed makes it particularly advantageous for processors who need quick startups or make frequent material changes," said Haynie. "For throughputs of up to 200 lb. [90 kg] per hour, it provides major advantages over desiccant systems."

o NovaDrier(TM). This membrane dryer eliminates need for desiccant by removing moisture with compressed air that flows through an adsorption membrane designed specifically for NOVATEC. Moving parts that are standard in desiccant dryers (process motor, regeneration heater and motor, and valves) are eliminated. Other than normal hopper cleanout, the only maintenance typically required is to change two filter elements. The membrane is rated to last 20 years under heavy use. "In our tests, the NovaDrier exhibited the highest energy costs per hour because of the energy consumed in generating compressed air," noted Haynie. "On the other hand, it is simpler and more compact than any other dryer of comparable capacity, entails less investment cost, and requires the least maintenance; in addition, it is mountable even on the smallest machines. As a result, we've sold 2,000 NovaDrier units since we introduced the system in 2000, and we expect continued growth for applications requiring throughputs under 225 lb. [100 kg] per hour."

NOVATEC, INC. is a leading supplier of resin drying, blending, and pneumatic conveying systems to plastics processors. The company specializes in custom-engineered material handling systems that meet specific process and production requirements. Its range of dryers is the broadest in the industry, including desiccant, hot air, compressed air, and infrared systems, as well as the patented NovaDrier(TM) membrane dryer, the NovaWheel(TM) desiccant wheel dryer, and the NovaVac II(TM) vacuum dryer. NOVATEC, Inc. is headquartered at 222 East Thomas Avenue, Baltimore, MD 21225 U.S.A. Tel: 410-789-4811. Fax: 410-789-4638. Email:

More from Fluid & Gas Flow Equipment

All Topics