Reducing hot-melt adhesive products’ time-to-cool period prior to forming is a productivity goal for adhesives manufacturers. Often, it can take 6 to 18 hours to form and package a standard batch of adhesives, depending on the finished product form. Every minute of cooling time that can be reduced results in increased productivity as well as a process cost reduction. For some applications, says its manufacturer, the Kenics heat exchanger has been effective in reducing time-to-cool when handling viscous, hot-melt adhesives.
One hot-melt adhesives manufacturer put Kenics to the test when the company was experiencing excessive forming and packaging time. First, the company incorporated scraped surface devices and vertical tanks to speed cooling, but the hot-melt adhesive still did not cool quickly enough. Then, DEN Group, a consulting firm the adhesives maker was working with, recommended Kenics, which is manufactured by Chemineer, Dayton, Ohio.
The heat exchanger incorporates static mixer technology is designed to provide high heat transfer coefficients and fast, uniform heat transfer. The heat exchanger consists of a continuous string of static mixer elements within each heat exchanger tube. Fluid flow is directed radially toward the pipe walls and back to the element, regardless of velocity. Additionally, momentum reversal and flow division also contribute to the mixing efficiency. All of the hot-melt adhesive would be continuously and completely intermixed to eliminate radial gradients in temperature, velocity and material composition.
Chemineer engineered and installed a custom jacketed Kenics heat exchanger system to effectively cool the product in less time than previous heat transfer devices. Using it, the hot-melt adhesives maker was able to reduce the time to form and package a batch of hot-melt adhesive from 18 hours to less than two hours, an improvement of more than 88 percent. The heat exchanger system was designed to remove 100°F (55°C) from molten materials at 4,000 lb/hr.
The heat exchanger solution required less floor space. Also, it used less energy than the previous heat transfer device because the only power needed was a small-horsepower pump to move the coolant through the shell side of the static mixer. (The mixer itself uses no outside power source.) The reduction in forming and packaging time increased productivity and optimized existing manufacturing capacity. The reduced heat history also improved the quality of the finished product, resulting in greater product consistency.