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Original Date: 03/17/1997
Revision Date: 01/18/2007
Best Practice : Pressure Nutsche
Since 1988, Polaroid has been implementing a multimillion dollar program to replace the traditional centrifuges and dryers at its Chemical Operations Division with pressure nutsche technology. This change has been improving the company’s Toxic Use and Waste Reduction performance and will reduce the Division’s air emissions.
Previously, products were isolated; washed on filter presses or in centrifuges; and dried in vacuum tray dryers. These dryers produced high VOC emissions, required labor intensive material handling, and had long cycle times. The process also exposed employees to VOC emissions, solvents, and fire risks. Pressure nutsches work as self- contained vessels to filter, dry, and separate chemical mixtures while removing vapors and emissions. Figure 2-5 shows a schematic of a typical pressure nutsche installation. Polaroid introduced pressure nutsches as a means to improve safety for employees, prevent pollution, and provide increased operational performance. The nutsches have also been accepted by environmental agencies as complying with the Clean Air Act requirements. To offset the high cost of pressure nutsches ($2 million each), Polaroid has been upgrading its facilities gradually.
Polaroid modified the pressure nutsches to facilitate its material handling and cleaning operations. Benefits gained by Polaroid over the past five years include a decrease in baseline VOC emissions from 180 to 40 tons per year; a 95% reduction in VOC emissions from filtration and drying operations over traditional processes; and an estimated 20% to 30% increase in solvent collection for on-site reuse or off-site fuel burning. Pressure nutsche technology has also improved employee safety by reducing solvent exposure, minimizing drum handling; and decreasing fire hazards from flammable solvents. Employees are no longer handling solvent-wet cakes. Operational benefits include improved efficiency, reduced cycle times, increased product yields by 2% to 5%, and reduced labor hours.
Figure 2-5. F360 Pressure Nutsche System
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