New Fluid Bed Dryer Increases Production By 50% While Saving $60,000.00 Per Year In Maintenance
No one could determine precisely why the mysterious goo was forming on their dryer but the operators at Complete Spill Solutions, Watertown, New York, had had enough of trying to remove the sticky sap-like goo that was blinding its screens and CEO Geoff Perry was growing increasingly concerned about its impact on productivity. Drying up to 75% moisture recovered fibers from the waste stream of a paper mill, Mr. Perry had targeted production rates of 2,000 lbs./hr. but the design of the round fluid bed dryer hampered his efforts.
“This ‘goo’ was a horrendous problem,” says Mr. Perry. “We had to shut down the entire line once per month to clean the dryer, which was a major undertaking. In labor costs and lost production alone, this cost about $5,000.00 every month.” The dryer’s sintered screen design was prone to warping that created peaks, valleys and dead spaces where the gooey residue would form, gather and clog. This blinding prevented efficient airflow and caused severe drops in productivity. “It would get progressively worse until the product came out wet and we had no choice but to shut down,” adds Mr. Perry.
Then the paper product manufacturer replaced his troublesome dryer with a vibrating fluid bed dryer from The Witte Co., Washington, New Jersey (www.witte.com). Witte has been designing and manufacturing vibrating fluid bed dryers, coolers, dewaterers, screeners and other process equipment for companies including Merck, Kraft, Nestle, Morton, DuPont and ChevronTexaco since 1938. “Witte has been involved in this for almost 70 years,” says Mr. Perry, “and combined with Gary’s (Witte representative Gary Datta of I-2/BPST, Inc., Union, New Jersey) extensive process knowledge I was confident in their ability to solve the problem. But I never imagined they would increase my production by 50%!”
The first step was to identify the root of the problem, which lay in the sintered screen design of the round dryer. The gooey buildup, according to Mr. Datta, was a symptom of inefficient airflow. “One reason I represent Witte is they have a keen understanding of vertical airflow engineering,” says Mr. Datta. “That’s the foundation of an efficient drying operation and one of the reasons their dryers are so effective and energy-efficient.” Instead of using sintered screens with fine holes that attract clogs, Witte uses a proprietary wedge-wire deck with 0.010 inches wide tapered slots with 1/8″ thick triangular wires. This wedge-wire construction of FDA-approved stainless steel establishes openings for airflow that prevent blinding, promote uniform fluidization and ensure plug flow. Since installing the Witte dryer in May 2003, Perry has been able to ratchet up production to an impressive 3,000 lbs./hr., exceeding the target by 50%. “Witte’s approach is based on designing a system that meets a target production and quality rate,” explains Mr. Perry. “They would have been able to meet whatever target I wanted.” And the mysterious gooey residue? “Eliminated. We haven’t had a single clog since we installed the Witte dryer,” says Mr. Perry. “In fact, we haven’t even had to clean it yet!”
But if Perry’s operators ever want to clean the system, Witte engineers have made their job incredibly easy. Cleanable by design, the 42″ wide x 18′ long dryer is built with a davit lifting system that enables one person to raise the entire cover off of the fluid bed with one hand, providing instant access to the deck at chest level. Since the previous dryer operated eight feet off of the floor, the frequent cleanings required personal visits over a tall platform and carried an inherent safety risk. The Witte dryer, by operating at floor level, eliminated the safety risk and also enabled Perry to bring the entire processing line to the floor level. “Our entire line had been built to accommodate the eight-foot height of the old dryer,” says Mr. Perry. “Now we have much greater, safer and easier access to every piece of equipment.” Reorienting the line onto a single level also eliminated a second source of frustration: a belt conveyor that was being used to raise the fibrous sludge eight feet high to the dryer’s infeed. The material frequently stuck to the belt and required manual removal, slowing production. The Witte dryer’s infeed, by contrast, stands only 3-1/2′ off the floor, permitting the use of an ultra-short infeed conveyor. “The Witte dryer is so much easier to use and it is so efficient that our operators just love it,” says Mr. Perry.
The Witte dryer consistently meets the targeted 8% moisture content, it is easily adjusted when a 10%-12% specification is desired and product integrity is exceptional. “We’re extremely pleased with the Witte dryer,” says Mr. Perry.
For more information, contact The Witte Company, Inc. at 908-689-6500.