NYS Governor's Awards for Pollution Prevention - DuPont Yerkes Plant
DuPont Yerkes Plant, Tonawanda, New York
DuPont Yerkes produces a polymethyl methacrylate polymer, used for wall cladding and other building applications for counter tops and sinks, and a polyvinyl fluoride film, used for covering applications. Approximately 500 people are employed at this facility. Their pollution prevention project, a two-phased methylene chloride (DCM) reduction, was started in 1988 and finalized in 1993. The project successfully reduced the amount of methylene chloride used at this facility from 240,000 pounds in 1988 to 7,000 pounds in 1993, a 97 percent reduction in use.
Methodologies and Procedures
An important part of the pollution prevention project was to identify and reduce the largest source of DCM usage: the cleaning of the mix heads on the shape casting line for polymer manufacturing. DuPont opted to substitute a non-hazardous solvent, dibasic ester (DBE), for the DCM in the cleaning of the shape casting heads. The substitution resulted in an annual reduction of 120,000 pounds of DCM by 1990.
Renewed Phase I and Phase II
Based on an internal audit, it was decided to renew the effort to reduce DCM usage. Attention focused on the cleaning of the sheetline mix heads, a two-step process. The first step was to use DCM to flush/dissolve any semi-soft acrylic residue and the second step was to dissolve the hardened residue. Again with DCM, a new system was developed that involves: flushing with methyl methacrylate (a process component); light soaking with DCM to soften the hardened residue; a "hot, sand bead blast" to remove hardened residue; and operator education on prevention of excessive buildup of hardened acrylic. Under the new system, an annual reduction of 80,000 pounds of DCM was realized by late 1990.
Phase II included a team of employees, including laboratory analysts, line operators and maintenance mechanics, that helped develop recommendations and implement changes to further reduce DCM use. The principal remaining use of DCM was for general cleaning purposes: to remove acrylic residues that had hardened on surfaces such as floors and machinery. The team recommended the replacement of DCM use by a combination of chemical substitution and revised operating procedures. These included: a 50-50 solvent solution of two non-hazardous alternatives, 1-methyl-2-pyrrolidone with ethyl-3-ethoxypropionate; and operator education. Based on this effort, an annual reduction of 23,000 pounds of DCM was achieved by 1993.
Through the project, the company realized pollution reductions of:
- 97 percent reduction of DCM usage
- Elimination of solvent fumes to workers and the community.
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This page was last modified March 8, 1999