US 4,265,642 AGranted

Process of removal of solvent vapors

AssigneeAbcor, Inc.

InventorsLeon Mir, Joseph Zahka

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Abstract

A process for removing volatile vapor solvents, particularly from paint-spray booths and paint dryers, and recovering such solvents, which process comprises: intimately contacting the solvent-laden air with a multiphase scrubbing media, particularly a water stream containing an oil-in-water emulsion or a surfactant or a powdered activated carbon, to capture and to dissolve the solvent vapor in the dispersed phase of the scrubbing media in a gas scrubber; removing the solvent-enriched scrubbing media and concentrating the solvent-enriched scrubbing media employing an ultrafiltration device; stripping the solvent from the concentrated solvent-enriched scrubbing media from the ultrafiltration device to remove and recover the solvent, while recycling the scrubbing media for further contact with fresh solvent-laden air; and recycling the water carrier as a permeate for reuse in contacting the solvent-laden air.

Claims9

Dependent claims

A process for the removal of a volatile organic solvent from a solvent-laden air stream, which process comprises:

(a) intimately contacting and scrubbing the solvent-laden air stream with an aqueous, multiple-phase scrubbing media to provide a solvent-lean air stream and a solvent-rich scrubbing media, the scrubbing media comprising a surfactant-containing oil-in-water emulsion which forms micelles in the water phase of the emulsion, and wherein the solvent is dissolved in the oil portion of the oil-in-water emulsion in the solvent-rich scrubbing media;
(b) discharging the solvent-lean air stream;
(c) concentrating the solvent-rich scrubbing media in a low-pressure ultrafiltration-membrane unit having a feed zone and a permeate zone separated by a membrane which permits the passage of water, but retards the passage of the micelle portion of the oil-in-water emulsion of the scrubbing media, to provide a concentrated, solvent-rich scrubbing media in the feed zone and permeate water which passes through the membrane into the permeate zone;
(d) heating the concentrated solvent-rich scrubbing media to a temperature to volatilize the solvent, but insufficient to destabilize the oil-in-water emulsion from which the solvent is removed, to form a solvent vapor and a concentrated solvent-lean scrubbing media;
(e) condensing the solvent vapor;
and
(f) continuously recycling the concentrated solvent-lean surfactant oil-in-water scrubbing media and the permeate water from the permeate zone for use in the contacting and scrubbing of the solvent-laden air stream, to reconstitute a scrubbing media for use in the contacting and scrubbing steps,
whereby the volatile organic solvent is condensed, a solvent-lean air stream is discharged and the multiple-phase scrubbing media is continuously recycled and reused in removing the solvent from the solvent-laden air stream.

5 more elements

Dependencies are inferred from the claim text.