Process for recovering phosphate ester type hydraulic fluids from industrial waste liquids
AssigneeOutboard Marine Corporation
InventorsPablo M. Hernandez, William J. Luplow
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Abstract
Disclosed herein is a process for recovering a phosphate ester type hydraulic fluid from a waste liquid containing water, organic solvents and other impurities, such as polychlorinated biphenyls (PCB). After filtering to remove particulate matter, a heavy fraction separated from the waste liquid and consisting primarily of the hydraulic fluid is first subjected to a distillation step. A substantial portion of the PCB is removed as overhead from the distillation step and the bottoms containing the hydraulic fluid is subsequently evaporated, preferably in a thin film evaporator. The overhead from the evaporation step is condensed to recover the hydraulic fluid.
Claims11
A process for recovering a phosphate ester type hydraulic fluid from a waste liquid containing water, organic solvents and other impurities, which process comprises the steps of
- distilling the waste liquid at a temperature of about 190.degree. to about 260.degree. C. and at a pressure of about 2 to about 30 mm Hg,
- removing water, low boiling organic solvents, and other low boiling impurities as an overhead from the distillation step,
- removing the hydraulic fluid and high boiling impurities as liquid bottoms from the distillation step,
- evaporating the bottoms from the distillation step at a temperature of about 260.degree. to about 380.degree. C. and a pressure up to about 5 mm Hg,
- removing high boiling impurities as bottoms from the evaporation step,
- removing the hydraulic fluid as an overhead from the evaporation step, and
- condensing the overhead from the evaporation step to recover the hydraulic fluid.
Dependencies are inferred from the claim text.