GENERAL PROCESS DESCRIPTION
BEK Chemical Process Technologies, Inc. provides a two-stage polymer devolatilization system. The system is designed to concentrate dilute polymer solutions to nearly 100% polymer with only ppm levels of residual solvents and monomers. The system features two thin film vacuum polymer processing machines. Please refer to our Process Flow Sheet for a complete visualization.
Dilute polymer feed, supplied by the customer, is metered into the first thin film machine. A rotor evenly distributes the feed on the heated inner wall of the unit as a thin liquid film. The wall of the machine is heated using circulated hot oil. Vacuum levels are controlled to minimize the evaporation temperature. The rotor continuously refreshes the film promoting optimal conditions for solvent evaporation. Solvent vapors flow into an external vacuum condenser and are continuously removed and recovered. Partially processed polymer exits the first evaporator through a gear type polymer pump. The polymer is pumped directly to the second thin film machine. This machine is similar to the first, but is designed to process higher viscosity material. If required, it can operate at a lower pressure (1Torr) and higher temperature (450F). Polymer is pumped out of the second machine and processed through a strand die and water bath. The polymer strands are dried and cut by a pelletizer. All polymers leaving the units will have solvent and monomer residuals of less than 200 ppm and many will be less than 100 ppm. The final polymer product is in a safe to store and handle form (as opposed to the explosive dangers of a fine powder).
The combination of an extremely short residence time, low temperature, high turbulence, and quick surface renewal allows this method to successfully process heat-sensitive, viscous and fouling-type polymers.
Please Note: This is intended to be a simplified walk-through of our process. Refer to the referenced technical papers below for an in-depth discussion of the process and its benefits.
Click the links below to view information articles about our technical processes.
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Evaporation of Difficult Products
William L. Hyde, Business Manager; William B. Glover, P.E., Engineering Manager; LCI Corp., Charlotte, NC
Mass Transfer in the Luwa Filmtruder
James B. Lane, P.E., Luwa Corporation, Charlotte, North Carolina