Purge Vessel dries and cools polymer pellets.

Press Release Summary:

Purge vessel can be used as batch processor to dry and cool large mass of polymer pellets. Heated, dry air flows up through bottom of purge vessel while it is being filled with wet polymer pellets. As airflow continues, pellets are held under high volatile vapor pressure and low volatile partial pressure. When pellets are dry, vessel is purged with dehumidified air. In cooling phase, cool, dry air recirculates through vessel to cool polymer pellets to specified temperature.

Original Press Release:

Hosokawa Bepex's Batch Purge Vessel Economically Dries, Cools Polymer Pellets

MINNEAPOLIS - Hosokawa Bepex has developed a purge vessel for batch drying and cooling of polymer pellets that has resulted in costs savings compared to other drying methods. Normally, a purge vessel is used as a second-stage drier in a continuous process to reduce moisture or volatile content of pellets or a powder into the low parts per million (PPM) range. However, by successfully scaling up the results from a small pilot installation at the Hosokawa Bepex test laboratory, the company was able to adapt the purge vessel to an economical batch drying process.

One customer application involves the drying and cooling of two, 17,000-pound batches of polymer pellets down to 100 PPM of water in less than eight hours. In the process, heated dry air flows up through the bottom of the two purge vessels while they are being filled with wet polymer pellets. As airflow continues, the pellets are held under high volatile vapor pressure (as measured by pellet temperature) and low volatile partial pressure (by dilution of evolved moisture with the purge air) for an extended residence time.

When the pellets are dry, the vessels are then purged with dehumidified air to remove residual moisture that might condense during cooling. In the cooling phase, cool, dry air recirculates through the purge vessel to cool the polymer pellets to a specified temperature.

"We recommended a purge vessel for this application and ran a successful demonstration test in our Minneapolis pilot laboratory," says Tom Olson, Product Specialist. "We then used the test data to scale up the pilot system to two commercial size purge vessels that the customer purchased and installed. Our initial testing and subsequent customer experience has shown that a purge vessel can be used as a batch processor to efficiently dry and cool a large mass of material."

Hosokawa Bepex is a single-source provider of integrated powder and particle processing systems for size reduction, agglomeration, compaction, drying, briquetting, thermal processing, blending and mixing. The company's equipment brands include Bepex, K-G, Rietz, Schugi and Strong-Scott. Hosokawa Bepex is a member of the Hosokawa Micron Group, an international provider of equipment and technology for powder and particle processing, plastics processing and confectionery products. For more information, contact: Hosokawa Bepex, 333 NE Taft Street, Minneapolis, MN 55413. Phone: 612-331-4370; Fax 612-627-1444. Visit the web site at: www.bepex.com.

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