Vinyl Chloride Monomer Stripping of PVC Resins.
NIOSH 1981 Jan:40-48
A prototype stripping method for residual vinyl-chloride (75014) monomer (RVCM) was described for B. F. Goodrich polyvinyl-chloride (PVC) manufacturing facilities. The high levels of RVCM (10 to 30,000 parts per million (ppm)) at various points in the manufacturing process was a major source of worker exposure and atmospheric emission and also could expose customers during subsequent melt processing. Batch or continuous stripping was determined to provide the best and most rapid solution as compared to postpolymerization and other chemical modification methods. Batch stripping pilot operations were carried out in production facilities. Continuous stripping pilot operations were performed at the Brecksville, Ohio, research and development center. Batch stripping at higher temperatures significantly reduced RVCM levels, but the pilot stripping column (continuous process) was more efficient. The prototype unit used a modified distillation column and was constructed and installed at the Goodrich production facility in Avon Lake, Ohio. Engineering data, resin quality data, and RVCM levels at various stripping conditions were obtained from this unit for design of commercial units. Specific operation of commercial stripping units was described and diagrammed. Methods for improving energy utilization were also discussed. The author notes that the process is in operation commercially in all of Goodrich's domestic PVC facilities. The process was capable of handling PVC slurry streams with a wide range of RVCM (5,000 to 200,000ppm) and resins with a wide range of particle structure. The production units showed that RVCM could be removed on a routine basis to levels less than 1ppm without any apparent degradation of PVC properties. The stripping operation described also minimized worker exposure to vinyl-chloride monomer, minimized downstream air emissions, and improved recovery efficiency of vinyl-chloride.
Chemical-cleaning; Chlorinated-hydrocarbons; Workplace-studies; Industrial-hygiene; Industrial-hazards; Regulations; Occupational-exposure; Organic-solvents;
Symposium Proceedings. Control Technology in the Plastics and Resins Industry, Division of Physical Sciences and Engineering, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, DHHS (NIOSH) Publication No. 81-107