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US 10,093,562 B2Granted
Methods and compositions for the treatment and recovery of purge solvent
AssigneeEcolab USA Inc.
InventorsPaul Balent, Gordon M. Carter, Samuel P. Mooney, David W. Scheimann, Shayne B. Hare, Joseph P. Miknevich
Life of this patent
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Abstract
The present disclosure relates to purge fluids, methods of using the purge fluids, and systems to be used for recycling the purge fluids. In some aspects, the purge fluid may be used to clean or purge an automated spray coating apparatus, such as a paint gun. The purge fluid may include a solvent and water. After the purge fluid is utilized for purging or cleaning certain system components, the purge fluid may be treated, subjected to a liquid-solid separation technique, and reused as a purge fluid.
Claims17
A method of recovering purge fluid comprising:
- providing a spent purge fluid comprising water, a solvent, and a solid material, wherein the solid material comprises paint particles;
- adding an effective amount of one or more coagulants to the spent purge fluid, wherein the coagulant comprises aluminum chlorohydrate, cationized corn starch and polymer;
- adding an effective amount of one or more flocculants to the spent purge fluid, wherein the effective amount of one or more flocculants is added to the spent purge fluid before adding of the effective amount of one or more coagulants to the spent purge fluid, and wherein the one or more flocculants facilitate flocculation of the paint particles and the one or more flocculants comprises a partially hydrolyzed polyacrylamide polymer having a weight average molecular weight ranging from 2×106 to 20×106 Daltons and the portion of the polyacrylamide polymer having hydrolyzed acrylamide structural units should not exceed 30% by weight;
- allowing the flocculated paint particles to settle;
- thereby forming a settled solid material;
- and
- separating the flocculated paint particles from the spent purge fluid, thereby recovering the solvent, wherein the solvent is ethylene glycol monobutyl ether.
4 more elements
A method of reducing an amount of spent purge waste comprising:
- providing a spent purge waste comprising water, a solvent, and a solid material, wherein the solid material comprises a member selected from the group consisting of paint resins, pigments, and any combination thereof, wherein the solvent is ethylene glycol monobutyl ether;
- adding an effective amount of one or more coagulants to the spent purge waste wherein the coagulant consists of aluminum chlorohydrate, cationized corn starch and polymer;
- adding an effective amount of one or more flocculants to the spent purge waste, wherein the one or more flocculants facilitate flocculation of the solid material in the spent purge waste, and wherein the flocculant comprises a partially hydrolyzed polyacrylamide polymer having a weight average molecular weight ranging from 2×106 to 20×106 Daltons and the portion of the polyacrylamide polymer having hydrolyzed acrylamide structural units should not exceed 30% by weight;
- allowing the flocculated solid material to settle, thereby forming a settled solid material;
- separating the flocculated solid material from the water and the solvent;
- recycling the water and solvent;
- and
- disposing of only the flocculated solid material.
5 more elements
A method for cleaning a flow path of an automated painting apparatus comprising:
- a) providing an automated painting apparatus having a paint line in fluid communication with a paint gun;
- b) pumping a purge fluid comprising water and ethylene glycol monobutyl ether into an end of the paint line, whereby the purge fluid travels through the paint line, into the paint gun, and out of an end of the paint gun;
- c) collecting the purge fluid in a tank;
- d) adding an effective amount of one or more coagulants to the purge fluid wherein the coagulant comprises aluminum chlorohydrate, a cationized corn starch and polymer;
- e) adding an effective amount of one or more flocculants to the purge fluid, wherein the one or more flocculants facilitate flocculation of paint particles in the purge fluid, and wherein the flocculant comprises a partially hydrolyzed polyacrylamide polymer having a weight average molecular weight ranging from 2×106 to 20×106 Daltons and the portion of the polyacrylamide polymer having hydrolyzed acrylamide structural units should not exceed 30% by weight;
- f) allowing the flocculated paint particles to settle;
- g) separating the flocculated paint particles from the purge fluid;
- and
- h) transporting the separated purge fluid to a clean purge fluid supply tank, optionally wherein steps a) through h) are repeated a plurality of times.
6 more elements
Dependencies are inferred from the claim text.