Solvent Substitution and Equipment Modifications for Vapor Degreasing

摘要

With the increasing costs and liabilities associated with the disposal ofchlorinated solvents and increased concern over the occupational health effects of chlorinated solvents, substitution of a chlorinated solvent with an aqueous cleaner is a desirable alternative to consider. This paper describes a vapor degreasing operation at Vandenberg Air Force Base where 1,1,1-trichloroethane is used; an aqueous cleaning system reduces solvent wastes by 70%, solvent emissions by 100%, and annualized costs by 40%. Solvent substitution was compared to other alternatives including on-site distillation and reduction of solvent losses by either installing a refrigerated freeboard chiller and/or increasing the height of the freeboard. Substitution of 1,1,1-trichloroethane with an aqueous cleaner appears to be the best alternative.