CA2143563A1 - Process for reconcentrating overspray from one-component coating compositions - Google Patents
Process for reconcentrating overspray from one-component coating compositionsInfo
- Publication number
- CA2143563A1 CA2143563A1 CA002143563A CA2143563A CA2143563A1 CA 2143563 A1 CA2143563 A1 CA 2143563A1 CA 002143563 A CA002143563 A CA 002143563A CA 2143563 A CA2143563 A CA 2143563A CA 2143563 A1 CA2143563 A1 CA 2143563A1
- Authority
- CA
- Canada
- Prior art keywords
- molecular weight
- permeant
- water
- overspray
- booth
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000008199 coating composition Substances 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 41
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 60
- 238000001223 reverse osmosis Methods 0.000 claims abstract description 38
- 239000012465 retentate Substances 0.000 claims abstract description 36
- 239000000203 mixture Substances 0.000 claims abstract description 32
- 238000001728 nano-filtration Methods 0.000 claims abstract description 25
- 238000000108 ultra-filtration Methods 0.000 claims abstract description 20
- 239000007921 spray Substances 0.000 claims abstract description 14
- 238000011010 flushing procedure Methods 0.000 claims abstract description 4
- 238000005374 membrane filtration Methods 0.000 claims abstract description 3
- 235000003625 Acrocomia mexicana Nutrition 0.000 abstract 1
- 244000202285 Acrocomia mexicana Species 0.000 abstract 1
- 239000012528 membrane Substances 0.000 description 29
- 238000000576 coating method Methods 0.000 description 19
- 241000282320 Panthera leo Species 0.000 description 17
- 239000011248 coating agent Substances 0.000 description 15
- 238000000926 separation method Methods 0.000 description 8
- YFONKFDEZLYQDH-OPQQBVKSSA-N N-[(1R,2S)-2,6-dimethyindan-1-yl]-6-[(1R)-1-fluoroethyl]-1,3,5-triazine-2,4-diamine Chemical compound C[C@@H](F)C1=NC(N)=NC(N[C@H]2C3=CC(C)=CC=C3C[C@@H]2C)=N1 YFONKFDEZLYQDH-OPQQBVKSSA-N 0.000 description 7
- 239000007787 solid Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 229920002239 polyacrylonitrile Polymers 0.000 description 6
- 238000005507 spraying Methods 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 5
- 230000007717 exclusion Effects 0.000 description 5
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- 239000011347 resin Substances 0.000 description 5
- 238000004132 cross linking Methods 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 229920002492 poly(sulfone) Polymers 0.000 description 4
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- 239000002904 solvent Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- UEEJHVSXFDXPFK-UHFFFAOYSA-N N-dimethylaminoethanol Chemical compound CN(C)CCO UEEJHVSXFDXPFK-UHFFFAOYSA-N 0.000 description 3
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 229920003180 amino resin Polymers 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 238000010924 continuous production Methods 0.000 description 3
- 229960002887 deanol Drugs 0.000 description 3
- 239000012972 dimethylethanolamine Substances 0.000 description 3
- 239000003995 emulsifying agent Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 229920002635 polyurethane Polymers 0.000 description 3
- 239000004814 polyurethane Substances 0.000 description 3
- 230000000717 retained effect Effects 0.000 description 3
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000010923 batch production Methods 0.000 description 2
- 238000005345 coagulation Methods 0.000 description 2
- 230000015271 coagulation Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
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- 239000012510 hollow fiber Substances 0.000 description 2
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 229920001228 polyisocyanate Polymers 0.000 description 2
- 239000005056 polyisocyanate Substances 0.000 description 2
- 238000004094 preconcentration Methods 0.000 description 2
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 235000002639 sodium chloride Nutrition 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- CCTFMNIEFHGTDU-UHFFFAOYSA-N 3-methoxypropyl acetate Chemical compound COCCCOC(C)=O CCTFMNIEFHGTDU-UHFFFAOYSA-N 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 239000004953 Aliphatic polyamide Substances 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004693 Polybenzimidazole Substances 0.000 description 1
- 239000005062 Polybutadiene Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 229920002396 Polyurea Polymers 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 239000005862 Whey Substances 0.000 description 1
- 102000007544 Whey Proteins Human genes 0.000 description 1
- 108010046377 Whey Proteins Proteins 0.000 description 1
- 229920003231 aliphatic polyamide Polymers 0.000 description 1
- 229920000180 alkyd Polymers 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 1
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 229920002313 fluoropolymer Polymers 0.000 description 1
- 239000004811 fluoropolymer Substances 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 150000002334 glycols Chemical class 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000003204 osmotic effect Effects 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229920000090 poly(aryl ether) Polymers 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920002480 polybenzimidazole Polymers 0.000 description 1
- 229920002857 polybutadiene Polymers 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000414 polyfuran Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920003009 polyurethane dispersion Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 150000003384 small molecules Chemical class 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000003017 thermal stabilizer Substances 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 239000013008 thixotropic agent Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 239000012463 white pigment Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/027—Nanofiltration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/025—Reverse osmosis; Hyperfiltration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/025—Reverse osmosis; Hyperfiltration
- B01D61/026—Reverse osmosis; Hyperfiltration comprising multiple reverse osmosis steps
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/029—Multistep processes comprising different kinds of membrane processes selected from reverse osmosis, hyperfiltration or nanofiltration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/145—Ultrafiltration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/58—Multistep processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B14/00—Arrangements for collecting, re-using or eliminating excess spraying material
- B05B14/40—Arrangements for collecting, re-using or eliminating excess spraying material for use in spray booths
- B05B14/46—Arrangements for collecting, re-using or eliminating excess spraying material for use in spray booths by washing the air charged with excess material
- B05B14/462—Arrangements for collecting, re-using or eliminating excess spraying material for use in spray booths by washing the air charged with excess material and separating the excess material from the washing liquid, e.g. for recovery
- B05B14/463—Arrangements for collecting, re-using or eliminating excess spraying material for use in spray booths by washing the air charged with excess material and separating the excess material from the washing liquid, e.g. for recovery by means of ultrafiltration
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J11/00—Recovery or working-up of waste materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2317/00—Membrane module arrangements within a plant or an apparatus
- B01D2317/02—Elements in series
- B01D2317/022—Reject series
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2317/00—Membrane module arrangements within a plant or an apparatus
- B01D2317/02—Elements in series
- B01D2317/025—Permeate series
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2317/00—Membrane module arrangements within a plant or an apparatus
- B01D2317/08—Use of membrane modules of different kinds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B14/00—Arrangements for collecting, re-using or eliminating excess spraying material
- B05B14/40—Arrangements for collecting, re-using or eliminating excess spraying material for use in spray booths
- B05B14/46—Arrangements for collecting, re-using or eliminating excess spraying material for use in spray booths by washing the air charged with excess material
- B05B14/462—Arrangements for collecting, re-using or eliminating excess spraying material for use in spray booths by washing the air charged with excess material and separating the excess material from the washing liquid, e.g. for recovery
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/14—Paint wastes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
Abstract
The present invention relates to a multi-stage membrane filtration process for reconcentrating the overspray from a one-component, aqueous coating composition containing high molecular weight components having a weight average molecular weight of at least 2000 and at least 5% by weight, based on the totai weight of the organic components of the coating composition, of a low molecular weight component having a weight average molecular weight of less than 2000, that has been diluted with spray booth water from spray booths having wet flushing to form a booth/water overspray mixture by a) preconcentrating the booth water/overspray mixture in an ultrafiltration unit to obtain a first retentate containing high molecular weight components and a first permeant containing water and at least a portion of the low molecular weight components, b) treating said first permeant and the third permeant obtained in step c) below in a reverse osmosis unit to obtain a second permeant containing essentially pure water for recycle as booth water and a retentate containing low molecular weight components, c) treating said first and second retentates in a nanofiltration unit to obtain a third permeant containing water and a minor portion of low molecular weight components and a third retentate which largely corresponds in composition and concentration to said one-component, aqueous coating composition.
Description
21~3S63 Mo41 82 LeA 30, 193 PROCESS FOR RECONCENTRATING OVERSPRAY
FROM ONE-COMPONENT COATING COMPOSITIONS
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to a process for reconce"L~li"g the overspray of one-component, aqueous coating compositions from spray booths having wet extraction by a multi-stage membrane process using the resulting permeant as booth water and using the resulting retentate as an aqueous coating composition or as a constituent of an aqueous coating composition.
Description of the Prior Art The term "overspray" means those coating components that miss the target substrate during spray application of the coating and in the absence of particular precautions are lost.
Increasing environmental problems have prompted the recent development of a wide variety of processes aimed at reducing the volume of special waste arising from coatings overspray.
Conventionally, the overspray diluted by the spray booth water is coagulated in collecting basins for disposal. The underlying concept in some of the newer processes for water-thinnable coatings dispenses with coagulation and, instead, reconcentrates the overspray with care for reuse as a coating composition.
DE-OS 2,353,469 describes reconcenl,alillg the overspray by ultrafiltration. The diluted overspray flows past a semipermeable membrane such that the low molecular weight substances, in particular water but also low molecular weight dissolved binder components and auxiliary substances, pass through the membrane (i.e., the permeant or penetrant), while the principal components of the coating composition are retained by the membrane (i.e., the retentate).
/vj t/120994 21~3~6~
FROM ONE-COMPONENT COATING COMPOSITIONS
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to a process for reconce"L~li"g the overspray of one-component, aqueous coating compositions from spray booths having wet extraction by a multi-stage membrane process using the resulting permeant as booth water and using the resulting retentate as an aqueous coating composition or as a constituent of an aqueous coating composition.
Description of the Prior Art The term "overspray" means those coating components that miss the target substrate during spray application of the coating and in the absence of particular precautions are lost.
Increasing environmental problems have prompted the recent development of a wide variety of processes aimed at reducing the volume of special waste arising from coatings overspray.
Conventionally, the overspray diluted by the spray booth water is coagulated in collecting basins for disposal. The underlying concept in some of the newer processes for water-thinnable coatings dispenses with coagulation and, instead, reconcentrates the overspray with care for reuse as a coating composition.
DE-OS 2,353,469 describes reconcenl,alillg the overspray by ultrafiltration. The diluted overspray flows past a semipermeable membrane such that the low molecular weight substances, in particular water but also low molecular weight dissolved binder components and auxiliary substances, pass through the membrane (i.e., the permeant or penetrant), while the principal components of the coating composition are retained by the membrane (i.e., the retentate).
/vj t/120994 21~3~6~
DE-OS 3,428,300 describes the desirability of exclusively using demineralized water as the spray booth water in order to avoid overspray coagulation. The same objective is achieved by the process described in DE-OS 2,945,523 by the addition of emulsifying agents.
EP-A-0,141,171 discloses the possibility of continuous ull~rilll~lion. A portion of the mixture of booth water and overspray circulated in the spray booth circuit undergoes continuous separation and ull~rilllalion. The permeate is returned to the booth water. The physical and chemical properties of the retentate is checked to determine its suitability for reuse as a coating composition. The reconcentrated overspray may be reused after, for example, dilution or concenl,~lion.
WO 91/09666 describes the reworking of heat-curable, aqueous alkyd or acrylic resins by ull,drill,alion in the presence of an aliphatic amine to prevent the coating compositions from coalescing and a glycol derivative to adjust the ulll~rilllalion throughput. These additives, however, have the disadvantages of affecting the quality of the worked-up coating composition and also polluting the exhaust air from the booth.
The new literature (for example JOT 10 (1992) 32 to 38, JOT 3 (1992) 28 to 33) discloses that the prior art ultrafiltration leads to serious problems with many coating systems, thus making it impractical. These problems may be due, for example, to a marked foaming tendency due to low molecular weight emulsifying agents or possibly low molecular weight binder components which pass into the permeant and accumulate.
The lost components may be crucial to the coating quality of the recycled material, making direct reuse of the retentate as coating composition impossible.
An object of the present invention is to develop a process which enables overspray from water-thinnable coating compositions to be Mo4182 ~ 2143S63 reworked to form new coating compositions having substantially the original composition and, thus, the original quality.
It has now surprisingly been found that this object may be achieved with the specific multi-stage membrane process described in 5 greater detail hereinafter.
Multi-stage membrane processes are known and are applied, inter alia, in the whey, sea water, oil emulsions or latex waste water reworking sectors (see, for example, M. Mulder "Basic principles of membrane technology" Kluwer Academic Publishers (1991), R. Rautenbach, R.
10 Albrecht"Membran-trennverfahren: Ulll~rill,alion und Umkehrosmose"
[Membrane Separation Processes: Ultrafiltration and Reverse Osmosis], Otto Salle Verlag, Frankfurt am Main (1981? and DE-OS 4,126,483).
These references describe the many possibilities, including combining ull,~rillralion with reverse osmosis. The permeant from ull,drill~lion, 15 which contains low molecular weight components, is reconcenlraled by reverse osmosis. The retentate from reverse osmosis is fed again into the ultrafiltration feed stream.
EP-A-0,553,684 describes a multi-stage membrane process for reconcentrating the overspray from water-dilutable coating compositions 20 in spray booths having wet flushing, in which the booth circulation water is preconcentrated in a continuous manner in an ull,~rillralion unit and the permeant is returned as circulation water. Final concentration is performed batch-wise in a further ull,~rill,alion unit. The permeant from the final concentration stage may be reconcentrated by a reverse 25 osmosis stage downstream. Because there is no provision for returning the retentate from reverse os,~nosis into the ultrafiltration feed, it is not possible with this arrangement to recover the overspray as a coating having essentially the original composition.
Mo41 82 EP-A 0,567,915 describes the possibility of returning the retentate from the reverse osmosis stage either into the preconcentration stage or into the final concentration stage. Reconcentration of low molecular weight components by reverse osmosis is only practical up to relatively low concentrations of at the most 5%, due to osmotic pressure build-up, so that redilution occurs as a result of returning the retentate from reverse osmosis into the ull~tlrilll~lion stages. Because of the poor retention performance of ultrafiltration in the case of soluble low molecular weight coating components, the coating composition recovered in this process does not have virtually the original composition.
SUMMARY OF THE INVENTION
The present invention relates to a multi-stage membrane filtration process for reconcentrating the overspray from a one-component, aqueous coating composition containing high molecular weight components having a weight average molecular weight of at least 2000 and at least 5% by weight, based on the total weight of the organic components of the coating composition, of a low molecular weight component having a weight average molecular weight of less than 2000, that has been diluted with spray booth water from spray booths having wet flushing to form a booth/water overspray mixture by a) preconcentrating the booth water/overspray mixture in an ultrafiltration unit to obtain a first retentate containing high molecular weight components and a first permeant containing water and at least a portion of the low molecular weight components, b) treating said first permeant and the third permeant obtained in step c) below in a reverse osmosis unit to obtain a second permeant containing essentially pure water for recycle as booth water and a retentate containing low molecular weight components, Mo41 82 21~3~63 c) treating said first and second retentates in a nanofiltration unit to obtain a third permeant containing water and a minor portion of low molecular weight components and a third retentate which largely corresponds in composition and concentration to said one-component, aqueous coating composition.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a flow chart of an embodiment of a continuous process according to the invention.
Figure 2 is a flow chart of a first embodiment of a batch process according to the invention.
Figure 3 is a flow chart of a second embodiment of a batch process according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
In the context of the present invention "ulllarilll~lion" means a known membrane separation process performed using membranes having an exclusion limit of 1,000 to 100,000, preferably from 10,000 to 100,000 g/mol, at differential pressures of 1 to 10, preferably 2 to 7 bar.
Nanofiltration is also a pressure permeation process and, in terms of separation performance, is classified between ullldrillldlion and reverse osmosis (see, for example, R. Rautenbach, G. Schneider, Final Report on the DFG [German Research Association] research project on "Nanofiltration", RWTH [Technical University of Rhineland-Westphalia] in Aachen (1993). In the context of the present invention "nanofiltration"
means a known membrane separation process performed using membranes having an exclusion limit of 200 to 2,000, preferably from 500 to 1,000 g/mol, at differential pressures of 12 to 40, preferably 12 to 30 bar.
In the context of the present invention "reverse osmosis" means a known membrane separation process in which membranes are utilized Mo41 82 ~ 2143563 that are capable of 95 wt-%, preferably at least 98 wt-%, retention of common salt. The trans-membrane pressure difference is about 15 to 100, preferably 25 to 75 bar.
The permeant flow, i.e., the speed of reconcentration, in all of the 5 membrane separation processes previously described is influenced predominantly by the trans-membrane pressure difference. When the process according to the invention is carried out, the permeant flows are about 5 to 200, preferably 10 to 100 llm2/h in the ultrafiltration stage, about 5 to 100, preferably 10 to 75 llm2/h in reverse osmosis, and about 10 5 to 100, preferably 10 to 50 llm2/h in nanofiltration.
All conventional commercial membrane modules are suitable for the ull,~rill,alion unit utilized in the process according to the invention, such as cushion, plate, spirally wound, tubular, capillary or hollow fiber modules. Examples of materials used to manufacture the membranes 15 include polysulphone, polyacrylonitrile, polyethylene, Teflon resin, porous carbon, ceramic, cellulose acetate, polyurea, aromatic or aliphatic polyamides, sulphonated polyaryl ethers, polyfuran, polybenzimidazole, various fluoropolymers and polyether aromatics such as polyimide or polyimidazopyrrolidone. Polysulphone or polyacrylonitrile plate or tubular 20 modules are preferably used.
All conventional commercial membrane modules, such as spirally wound, tubular, capillary or hollow fiber modules, are suitable for the reverse osmosis unit. Cushion or plate modules may be used, but are less preferred. The membranes may be manufactured from the same 25 materials as the ultrafiltration membranes. Polysulphone or polyacrylonitrile spirally wound modules are preferably used.
The same conventional commercial module types and membrane materials may be used for the nanofiltration unit as described for Mo41 82 21~3563 ultrafiltration. Cushion, plate or tubular modules of polypiperazinamide, polysulphone or polyacrylonitrile are preferably used.
The process according to the invention is suitable for reconcentrating booth water/overspray mixtures formed during the 5 processing of one-component, aqueous coating compositions. Examples of these compositions include physically drying coating compositions based on polyurethane or polyacrylate dispersions, coating compositions based on fatty acid-modified, polyurethane or polyacrylate dispersions, aqueous coating compositions based on polybutadiene, unsaturated 10 polyesters or polyacrylates or coating compositions containing based on hydroxy-functional polyesters, polyacrylates or polyurethanes combined with amino resins or blocked polyisocyanates as cross-linking resins.
Pigments, fillers and other additives for coating compositions, such as levelling agents, gloss improvers, anti-sedimentation agents, 15 thickeners, thixotropic agents, antioxidants and thermal stabilizers, which may optionally be present in the coating compositions, may also be reconcentrated.
The binders of the coating compositions are either dissolved or dispersed by the use of internal or external emulsifying agents. The 20 transitions between these states are fluid. The binders generally have average molecular weights of 2,000 to 100,000 g/mol, and frequently have broad molecular weight distributions so that low molecular weight components having molecular weights of less than 2,000 g/mol may also be present. The low molecular weight components exert a decisive ~5 influence on important product properties such as flow and gloss.
The cross-linking resins in stoving systems, such as amino cross-linking resins or blocked polyisocyanates, conventionally have average molecular weights of 500 to 2,000 g/mol. Therefore, they make a Mo41 82 ~ 21~356~
substantial contribution to the proportion of low molecular weight components in stoving coating compositions.
In the case of anionically modified binders the coating composition additionally contains amines, such as ammonia, triethylamine or dimethyl-5 ethanolamine, as neutralizing agents. The degree of retention of theseamines in the reverse osmosis stage is also high.
The majority of water-reducible coating compositions contain 0.1 to 15%, preferably 0.5 to 10%, of iow molecular weight solvents such as glycolether, N-methylpyrrolidone or methoxypropylacetate. These 10 solvents are also have an important influence on the properties of the resulting coatings.
In the coating compositions used in the process according to the invention, the proportion of components having a weight average molecular weight of less than 2,000 g/mol is at least 5 wt-%, preferably 15 10 to 60 wt-%; the proportion of components having a molecular weight of less than 1,000 g/mol is preferably at least 5 wt-%; and the proportion of coating components having a molecular weight of less than 500 g/mol, preferably less than 200 g/mol, is at least 0.5 wt-%, preferably at least 1.0%. The preceding percentages are based on the total weight of the 20 organic components of the coating compositions.
The solids content of these coating compositions is generally about 20 to 70, preferably 30 to 70 wt-%, while that of the overspray diluted with the spray booth water is generally about 0.05 to 20, preferably 0.5 to 10 wt-%. In the context of the present invention 25 "reconcentration" means the recovery from the overspray/booth water of an aqueous coating composition having virtually the original composition such that it may be reused as a coating composition or as a constituent of a coating composition.
Mo41 82 , g The process according to the invention is suitable for all one-component, aqueous coating compositions which have previously been worked up solely by ull,~rill,~lion. Preferably, the process according to the invention is used with coating compositions which either cannot be 5 worked up by ull,~rill,~lion or which are obtained in an unsatisfactory form due to the loss of components essential to the coating composition.
Fig. 1 set forth the process according to the invention in which:
(1) represents the booth water circuit;
(2) represents the part of the booth water circuit containing a booth water/overspray mixture to be reconcentrated;
EP-A-0,141,171 discloses the possibility of continuous ull~rilll~lion. A portion of the mixture of booth water and overspray circulated in the spray booth circuit undergoes continuous separation and ull~rilllalion. The permeate is returned to the booth water. The physical and chemical properties of the retentate is checked to determine its suitability for reuse as a coating composition. The reconcentrated overspray may be reused after, for example, dilution or concenl,~lion.
WO 91/09666 describes the reworking of heat-curable, aqueous alkyd or acrylic resins by ull,drill,alion in the presence of an aliphatic amine to prevent the coating compositions from coalescing and a glycol derivative to adjust the ulll~rilllalion throughput. These additives, however, have the disadvantages of affecting the quality of the worked-up coating composition and also polluting the exhaust air from the booth.
The new literature (for example JOT 10 (1992) 32 to 38, JOT 3 (1992) 28 to 33) discloses that the prior art ultrafiltration leads to serious problems with many coating systems, thus making it impractical. These problems may be due, for example, to a marked foaming tendency due to low molecular weight emulsifying agents or possibly low molecular weight binder components which pass into the permeant and accumulate.
The lost components may be crucial to the coating quality of the recycled material, making direct reuse of the retentate as coating composition impossible.
An object of the present invention is to develop a process which enables overspray from water-thinnable coating compositions to be Mo4182 ~ 2143S63 reworked to form new coating compositions having substantially the original composition and, thus, the original quality.
It has now surprisingly been found that this object may be achieved with the specific multi-stage membrane process described in 5 greater detail hereinafter.
Multi-stage membrane processes are known and are applied, inter alia, in the whey, sea water, oil emulsions or latex waste water reworking sectors (see, for example, M. Mulder "Basic principles of membrane technology" Kluwer Academic Publishers (1991), R. Rautenbach, R.
10 Albrecht"Membran-trennverfahren: Ulll~rill,alion und Umkehrosmose"
[Membrane Separation Processes: Ultrafiltration and Reverse Osmosis], Otto Salle Verlag, Frankfurt am Main (1981? and DE-OS 4,126,483).
These references describe the many possibilities, including combining ull,~rillralion with reverse osmosis. The permeant from ull,drill~lion, 15 which contains low molecular weight components, is reconcenlraled by reverse osmosis. The retentate from reverse osmosis is fed again into the ultrafiltration feed stream.
EP-A-0,553,684 describes a multi-stage membrane process for reconcentrating the overspray from water-dilutable coating compositions 20 in spray booths having wet flushing, in which the booth circulation water is preconcentrated in a continuous manner in an ull,~rillralion unit and the permeant is returned as circulation water. Final concentration is performed batch-wise in a further ull,~rill,alion unit. The permeant from the final concentration stage may be reconcentrated by a reverse 25 osmosis stage downstream. Because there is no provision for returning the retentate from reverse os,~nosis into the ultrafiltration feed, it is not possible with this arrangement to recover the overspray as a coating having essentially the original composition.
Mo41 82 EP-A 0,567,915 describes the possibility of returning the retentate from the reverse osmosis stage either into the preconcentration stage or into the final concentration stage. Reconcentration of low molecular weight components by reverse osmosis is only practical up to relatively low concentrations of at the most 5%, due to osmotic pressure build-up, so that redilution occurs as a result of returning the retentate from reverse osmosis into the ull~tlrilll~lion stages. Because of the poor retention performance of ultrafiltration in the case of soluble low molecular weight coating components, the coating composition recovered in this process does not have virtually the original composition.
SUMMARY OF THE INVENTION
The present invention relates to a multi-stage membrane filtration process for reconcentrating the overspray from a one-component, aqueous coating composition containing high molecular weight components having a weight average molecular weight of at least 2000 and at least 5% by weight, based on the total weight of the organic components of the coating composition, of a low molecular weight component having a weight average molecular weight of less than 2000, that has been diluted with spray booth water from spray booths having wet flushing to form a booth/water overspray mixture by a) preconcentrating the booth water/overspray mixture in an ultrafiltration unit to obtain a first retentate containing high molecular weight components and a first permeant containing water and at least a portion of the low molecular weight components, b) treating said first permeant and the third permeant obtained in step c) below in a reverse osmosis unit to obtain a second permeant containing essentially pure water for recycle as booth water and a retentate containing low molecular weight components, Mo41 82 21~3~63 c) treating said first and second retentates in a nanofiltration unit to obtain a third permeant containing water and a minor portion of low molecular weight components and a third retentate which largely corresponds in composition and concentration to said one-component, aqueous coating composition.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a flow chart of an embodiment of a continuous process according to the invention.
Figure 2 is a flow chart of a first embodiment of a batch process according to the invention.
Figure 3 is a flow chart of a second embodiment of a batch process according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
In the context of the present invention "ulllarilll~lion" means a known membrane separation process performed using membranes having an exclusion limit of 1,000 to 100,000, preferably from 10,000 to 100,000 g/mol, at differential pressures of 1 to 10, preferably 2 to 7 bar.
Nanofiltration is also a pressure permeation process and, in terms of separation performance, is classified between ullldrillldlion and reverse osmosis (see, for example, R. Rautenbach, G. Schneider, Final Report on the DFG [German Research Association] research project on "Nanofiltration", RWTH [Technical University of Rhineland-Westphalia] in Aachen (1993). In the context of the present invention "nanofiltration"
means a known membrane separation process performed using membranes having an exclusion limit of 200 to 2,000, preferably from 500 to 1,000 g/mol, at differential pressures of 12 to 40, preferably 12 to 30 bar.
In the context of the present invention "reverse osmosis" means a known membrane separation process in which membranes are utilized Mo41 82 ~ 2143563 that are capable of 95 wt-%, preferably at least 98 wt-%, retention of common salt. The trans-membrane pressure difference is about 15 to 100, preferably 25 to 75 bar.
The permeant flow, i.e., the speed of reconcentration, in all of the 5 membrane separation processes previously described is influenced predominantly by the trans-membrane pressure difference. When the process according to the invention is carried out, the permeant flows are about 5 to 200, preferably 10 to 100 llm2/h in the ultrafiltration stage, about 5 to 100, preferably 10 to 75 llm2/h in reverse osmosis, and about 10 5 to 100, preferably 10 to 50 llm2/h in nanofiltration.
All conventional commercial membrane modules are suitable for the ull,~rill,alion unit utilized in the process according to the invention, such as cushion, plate, spirally wound, tubular, capillary or hollow fiber modules. Examples of materials used to manufacture the membranes 15 include polysulphone, polyacrylonitrile, polyethylene, Teflon resin, porous carbon, ceramic, cellulose acetate, polyurea, aromatic or aliphatic polyamides, sulphonated polyaryl ethers, polyfuran, polybenzimidazole, various fluoropolymers and polyether aromatics such as polyimide or polyimidazopyrrolidone. Polysulphone or polyacrylonitrile plate or tubular 20 modules are preferably used.
All conventional commercial membrane modules, such as spirally wound, tubular, capillary or hollow fiber modules, are suitable for the reverse osmosis unit. Cushion or plate modules may be used, but are less preferred. The membranes may be manufactured from the same 25 materials as the ultrafiltration membranes. Polysulphone or polyacrylonitrile spirally wound modules are preferably used.
The same conventional commercial module types and membrane materials may be used for the nanofiltration unit as described for Mo41 82 21~3563 ultrafiltration. Cushion, plate or tubular modules of polypiperazinamide, polysulphone or polyacrylonitrile are preferably used.
The process according to the invention is suitable for reconcentrating booth water/overspray mixtures formed during the 5 processing of one-component, aqueous coating compositions. Examples of these compositions include physically drying coating compositions based on polyurethane or polyacrylate dispersions, coating compositions based on fatty acid-modified, polyurethane or polyacrylate dispersions, aqueous coating compositions based on polybutadiene, unsaturated 10 polyesters or polyacrylates or coating compositions containing based on hydroxy-functional polyesters, polyacrylates or polyurethanes combined with amino resins or blocked polyisocyanates as cross-linking resins.
Pigments, fillers and other additives for coating compositions, such as levelling agents, gloss improvers, anti-sedimentation agents, 15 thickeners, thixotropic agents, antioxidants and thermal stabilizers, which may optionally be present in the coating compositions, may also be reconcentrated.
The binders of the coating compositions are either dissolved or dispersed by the use of internal or external emulsifying agents. The 20 transitions between these states are fluid. The binders generally have average molecular weights of 2,000 to 100,000 g/mol, and frequently have broad molecular weight distributions so that low molecular weight components having molecular weights of less than 2,000 g/mol may also be present. The low molecular weight components exert a decisive ~5 influence on important product properties such as flow and gloss.
The cross-linking resins in stoving systems, such as amino cross-linking resins or blocked polyisocyanates, conventionally have average molecular weights of 500 to 2,000 g/mol. Therefore, they make a Mo41 82 ~ 21~356~
substantial contribution to the proportion of low molecular weight components in stoving coating compositions.
In the case of anionically modified binders the coating composition additionally contains amines, such as ammonia, triethylamine or dimethyl-5 ethanolamine, as neutralizing agents. The degree of retention of theseamines in the reverse osmosis stage is also high.
The majority of water-reducible coating compositions contain 0.1 to 15%, preferably 0.5 to 10%, of iow molecular weight solvents such as glycolether, N-methylpyrrolidone or methoxypropylacetate. These 10 solvents are also have an important influence on the properties of the resulting coatings.
In the coating compositions used in the process according to the invention, the proportion of components having a weight average molecular weight of less than 2,000 g/mol is at least 5 wt-%, preferably 15 10 to 60 wt-%; the proportion of components having a molecular weight of less than 1,000 g/mol is preferably at least 5 wt-%; and the proportion of coating components having a molecular weight of less than 500 g/mol, preferably less than 200 g/mol, is at least 0.5 wt-%, preferably at least 1.0%. The preceding percentages are based on the total weight of the 20 organic components of the coating compositions.
The solids content of these coating compositions is generally about 20 to 70, preferably 30 to 70 wt-%, while that of the overspray diluted with the spray booth water is generally about 0.05 to 20, preferably 0.5 to 10 wt-%. In the context of the present invention 25 "reconcentration" means the recovery from the overspray/booth water of an aqueous coating composition having virtually the original composition such that it may be reused as a coating composition or as a constituent of a coating composition.
Mo41 82 , g The process according to the invention is suitable for all one-component, aqueous coating compositions which have previously been worked up solely by ull,~rill,~lion. Preferably, the process according to the invention is used with coating compositions which either cannot be 5 worked up by ull,~rill,~lion or which are obtained in an unsatisfactory form due to the loss of components essential to the coating composition.
Fig. 1 set forth the process according to the invention in which:
(1) represents the booth water circuit;
(2) represents the part of the booth water circuit containing a booth water/overspray mixture to be reconcentrated;
(3) represents the ulLI~rilll~lio,l stage;
(4) represents the retentate from ~llr~rillr~lion;
(5) represents the permeant from ulll arill, alion;
(6) represents the reverse osmosis stage;
(7) represents the retentate from reverse osmosis;
(8) represents the permeant from reverse osmosis;
(9) represents the nanofiltration stage;
(10) represents the retentate from nanofiltration and (11 ) represents the permeant from nanofiltration.
Figs. 2 and 3 set forth other embodiments of the invention, in which the process according to the invention is carried out in batch-wise manner. In these figures (1) to (11) are defined as previously set forth and additionally (12) represents an intermediate tank for the booth water/overspray mixture which is to be supplied to reconcentration;
(13) represents an intermediate tank for the permeant from reverse osmosis which is virtually pure water for reuse;
Mo41 82 ~ 2143563 (14) represents an intermediate tank for the permeant from the reverse osmosis stage and (15) represents an intermediate tank for permeant from the nanofiltration stage.
The mixture of booth water and overspray (2), which is to be reconcentrated according to the invention, represents either the total quantity of mixture from wet extraction of the overspray or a portion of the mixture leaving the booth. In order to carry out the process according to the invention, the mixture (2) is guided into an ulll~rilll~lion 10 stage (3). In the ultrafiltration stage (3) the high molecular weight coatingcomponents are pre-concentrated in the retentate (4) to 10 to 90 wt-%, preferably from 25 to 75 wt-%, of the original coating conce~,lr;3liol,. The major part of the low molecular weight coating components are in the permeant (5) from the ultrafiltration stage. They are reconcentrated in a 15 reverse osmosis stage (6) to form the reverse osmosis retentate (7). The permeant (8) from the reverse osmosis stage contains virtually pure water and is returned into the booth circulation water circuit (1). The reverse osmosis retentate (7) is mixed with the ull,~rillr~lion ,etentale (4) and reconcentrated in a nanofiltration stage (9) until the nanorilll~lion 20 retentate (10) has attained the original coating concentration and, thus, virtually the original coating composition and quality. The nanofiltration retentate may therefore be used again without further modification as a ready-to-spray coating composition for the same purpose, or may be admixed with fresh coating composition. The nanofiltration permeant 25 (11), which contains small proportions of low molecular weight compounds that do not remain in the retentate (10), is mixed with the ultrafiltration permeant (5) and supplied to the reverse osmosis stage (6).
The permeant (8) leaving the reverse osmosis stage (6) generally contains "virtually pure" water. This means that the maximum organics Mo41 82 21~356~
Figs. 2 and 3 set forth other embodiments of the invention, in which the process according to the invention is carried out in batch-wise manner. In these figures (1) to (11) are defined as previously set forth and additionally (12) represents an intermediate tank for the booth water/overspray mixture which is to be supplied to reconcentration;
(13) represents an intermediate tank for the permeant from reverse osmosis which is virtually pure water for reuse;
Mo41 82 ~ 2143563 (14) represents an intermediate tank for the permeant from the reverse osmosis stage and (15) represents an intermediate tank for permeant from the nanofiltration stage.
The mixture of booth water and overspray (2), which is to be reconcentrated according to the invention, represents either the total quantity of mixture from wet extraction of the overspray or a portion of the mixture leaving the booth. In order to carry out the process according to the invention, the mixture (2) is guided into an ulll~rilll~lion 10 stage (3). In the ultrafiltration stage (3) the high molecular weight coatingcomponents are pre-concentrated in the retentate (4) to 10 to 90 wt-%, preferably from 25 to 75 wt-%, of the original coating conce~,lr;3liol,. The major part of the low molecular weight coating components are in the permeant (5) from the ultrafiltration stage. They are reconcentrated in a 15 reverse osmosis stage (6) to form the reverse osmosis retentate (7). The permeant (8) from the reverse osmosis stage contains virtually pure water and is returned into the booth circulation water circuit (1). The reverse osmosis retentate (7) is mixed with the ull,~rillr~lion ,etentale (4) and reconcentrated in a nanofiltration stage (9) until the nanorilll~lion 20 retentate (10) has attained the original coating concentration and, thus, virtually the original coating composition and quality. The nanofiltration retentate may therefore be used again without further modification as a ready-to-spray coating composition for the same purpose, or may be admixed with fresh coating composition. The nanofiltration permeant 25 (11), which contains small proportions of low molecular weight compounds that do not remain in the retentate (10), is mixed with the ultrafiltration permeant (5) and supplied to the reverse osmosis stage (6).
The permeant (8) leaving the reverse osmosis stage (6) generally contains "virtually pure" water. This means that the maximum organics Mo41 82 21~356~
content of this permeant is generally less than about 0.5, preferably less than 0.1 wt-%.
It is possible in accordance with the present invention to ultimately obtain as the nanofiltration retentate (10), an aqueous coating 5 composition which largely corresponds in composition and concentration to the original coating composition used. This is attributable principally to the step in the process in which the retentate (7) from reverse osmosis undergoes nanofiltration (9) together with the retentate (4) from ull,~rill,~lion. Despite the limited extent to which low molecular weight 10 components retained in the reverse osmosis are retained by nanorillralion, the reconcentration of such low molecular weight components from the combined permeants (5) and (11 ) has the effect of adjusting the balance and results in the presence of such low molecular weight components in the retentale (10), specifically in a percentage 15 which corresponds to their percentage in mixture (2) or in the original coating composition.
The continuous process according to the invention enables the solids content in the booth circulation water circuit (1) to be maintained permanently at a constant value of 0.05 to 20 wt-%, preferably 0.5 to 20 10 wt-%.
The process according to the invention may also be carried out batchwise (Figs. 2 and 3). In this case the overspray/booth water mixture (2) is first pumped from the booth circulation water circuit (1) into an intermediate tank (12). Thereafter, as in the continuous process, the 25 high molecular weight components are pre-concentrated in the ultrafiltration stage (3), the low molecular weight components are reconcentrated in the reverse osmosis stage (6) and the final concentration takes place in the nanofiltration stage (9). The reverse Mo41 82 ~ 214356~
It is possible in accordance with the present invention to ultimately obtain as the nanofiltration retentate (10), an aqueous coating 5 composition which largely corresponds in composition and concentration to the original coating composition used. This is attributable principally to the step in the process in which the retentate (7) from reverse osmosis undergoes nanofiltration (9) together with the retentate (4) from ull,~rill,~lion. Despite the limited extent to which low molecular weight 10 components retained in the reverse osmosis are retained by nanorillralion, the reconcentration of such low molecular weight components from the combined permeants (5) and (11 ) has the effect of adjusting the balance and results in the presence of such low molecular weight components in the retentale (10), specifically in a percentage 15 which corresponds to their percentage in mixture (2) or in the original coating composition.
The continuous process according to the invention enables the solids content in the booth circulation water circuit (1) to be maintained permanently at a constant value of 0.05 to 20 wt-%, preferably 0.5 to 20 10 wt-%.
The process according to the invention may also be carried out batchwise (Figs. 2 and 3). In this case the overspray/booth water mixture (2) is first pumped from the booth circulation water circuit (1) into an intermediate tank (12). Thereafter, as in the continuous process, the 25 high molecular weight components are pre-concentrated in the ultrafiltration stage (3), the low molecular weight components are reconcentrated in the reverse osmosis stage (6) and the final concentration takes place in the nanofiltration stage (9). The reverse Mo41 82 ~ 214356~
osmosis permeant (8) is collected in a tank (13) for subsequent reuse as booth water.
In a second embodiment of the batchwise process, which is less preferred, the ull~rilllalion, reverse osmosis and nanofiltration stages may be carried out independently of one another (Fig. 3). In this case the overspray/booth water mixture from the intermediate tank (12) is first preconcentrated in the ull,~rilllalion stage (3). The ultrafiltration retentate (4) is first collected in a further intermediate tank (14). The ultrafiltration permeant (5) is reconcentrated in the reverse osmosis stage (6). The reverse osmosis permeant (8) is collected in the tank (13) for reuse as booth water. The reverse osmosis retentate (7) is mixed with the ull,arillralion retentate (4) in the intermediate tank (14) and is supplied to the nanofiltration stage (9), where re-concentration takes place until the original coating composition concentration is reached. The nanofiltration permeant (11) is collected in a tank (15). It is mixed into the ull,drilll~lion permeant (5) upstream of the reverse osmosis stage (6) during the next reconcentration operation.
In the process according to the invention all of the auxiliary substances and additives present in the overspray are also present practically without loss in the retentate (10) which is ultimately obtained.
Accordingly, the only losses which must be made up in the process according to the invention are for the volatile coating components which may result from evaporation. Demineralized water is used as the booth water.
In the process according to the invention known materials and pumps are used in the individual separation stages, provided that they enable the process conditions according to the invention to be maintained. Pumps which are preferably used are those which subject Mo41 82 ~ 21~3563 the material to the iowest possible shear stress, e.g., diaphragm-actuated pumps.
The process according to the invention is generally carried out at room temperature (for example, 15 to 25C). It may be necessary to 5 cool the mixtures because of heat generated by friction during the process.
In most cases it is possible to reuse the resulting compositions without further modification. However1 in order to avoid fluctuations in quality it is also possible before reuse to mix with the concentrate a 10 quantity of fresh coating composition corresponding to the quantity arising through overspray. In this case the retentate is used as a constituent of a new coating composition.
The examples which follow aim to explain the invention in greater detail without, however, restricting it. The advantages of the process 15 according to the present invention may be seen by comparing the example according to the invention with the comparison example. All parts and percentages are by weight unless otherwise specified.
Example 1 The following coating composition was applied by spraying:
2049.5% polyester-polyurethane dispersion (at a concentration of 42% in a 52.3:4.6 blend of water/N-methylpyrrolidone, neutralized with 1.1% dimethylethanolamine, weight average molecular weight = 11,000, non-uniformity U = 3.0) 29.7% white pigment (Bayertitan R-KB-4, available from Bayer AG) 259.9% amino cross-linking resin ( Luwipal LR 8839, available from BASF AG, 90% in isobutanol) 8.5% water 1.2% dimethylethanolamine Mo41 82 .
In a second embodiment of the batchwise process, which is less preferred, the ull~rilllalion, reverse osmosis and nanofiltration stages may be carried out independently of one another (Fig. 3). In this case the overspray/booth water mixture from the intermediate tank (12) is first preconcentrated in the ull,~rilllalion stage (3). The ultrafiltration retentate (4) is first collected in a further intermediate tank (14). The ultrafiltration permeant (5) is reconcentrated in the reverse osmosis stage (6). The reverse osmosis permeant (8) is collected in the tank (13) for reuse as booth water. The reverse osmosis retentate (7) is mixed with the ull,arillralion retentate (4) in the intermediate tank (14) and is supplied to the nanofiltration stage (9), where re-concentration takes place until the original coating composition concentration is reached. The nanofiltration permeant (11) is collected in a tank (15). It is mixed into the ull,drilll~lion permeant (5) upstream of the reverse osmosis stage (6) during the next reconcentration operation.
In the process according to the invention all of the auxiliary substances and additives present in the overspray are also present practically without loss in the retentate (10) which is ultimately obtained.
Accordingly, the only losses which must be made up in the process according to the invention are for the volatile coating components which may result from evaporation. Demineralized water is used as the booth water.
In the process according to the invention known materials and pumps are used in the individual separation stages, provided that they enable the process conditions according to the invention to be maintained. Pumps which are preferably used are those which subject Mo41 82 ~ 21~3563 the material to the iowest possible shear stress, e.g., diaphragm-actuated pumps.
The process according to the invention is generally carried out at room temperature (for example, 15 to 25C). It may be necessary to 5 cool the mixtures because of heat generated by friction during the process.
In most cases it is possible to reuse the resulting compositions without further modification. However1 in order to avoid fluctuations in quality it is also possible before reuse to mix with the concentrate a 10 quantity of fresh coating composition corresponding to the quantity arising through overspray. In this case the retentate is used as a constituent of a new coating composition.
The examples which follow aim to explain the invention in greater detail without, however, restricting it. The advantages of the process 15 according to the present invention may be seen by comparing the example according to the invention with the comparison example. All parts and percentages are by weight unless otherwise specified.
Example 1 The following coating composition was applied by spraying:
2049.5% polyester-polyurethane dispersion (at a concentration of 42% in a 52.3:4.6 blend of water/N-methylpyrrolidone, neutralized with 1.1% dimethylethanolamine, weight average molecular weight = 11,000, non-uniformity U = 3.0) 29.7% white pigment (Bayertitan R-KB-4, available from Bayer AG) 259.9% amino cross-linking resin ( Luwipal LR 8839, available from BASF AG, 90% in isobutanol) 8.5% water 1.2% dimethylethanolamine Mo41 82 .
1.0% flow aid (Tegopren 100, Tego Chemie Service GmbH, 10%
in water) 0.2% cross-linking agent (Fluorad FC 129.3 M) The coating was diluted with water to a spraying viscosity of 35 s 5 (DlN-4-beaker/23C) before spray application. The solids content was about 59% and the pH was about 8.8.
Demineralized water was used as the booth water.
The solids content of the booth water/overspray mixture was 5%
when the spraying operation was complete.
A polyacrylonitrile membrane having an exclusion limit of 50,000 g/mol was used in the ull,drillralion stage for preconcentration.
Ultrafiltration was continued at a pressure of 4 bar until the solids content of the retentate was 30%.
Reconcentration of the combined permeants from the ull,ariill~lion 15 and nanofiltration stages took place in the reverse osmosis stage using a modified polyamide membrane capable of over 98% retention of common salt at a pressure of 30 bar. The permeant, containing less than 0.1%
organics, was reused as the booth water in the next spraying operation.
The combined retentates from ulll~rill,~lion and reverse osmosis 20 were reconcentrated to the original solids content of 59% in the nanofiltration stage which took place in parallel with ulllarilll~lion and reverse osmosis. A polypiperazinamide membrane having an exclusion limit of 1,000 g/mol was used at a pressure of 20 bar. The nanofiltration permeant was mixed with the ull,~rill,alion permeant and supplied to the 25 reverse osmosis unit.
The resulting coating composition was identical to the original coating composition in all properties relating to coating technology, including hardness, drying rate, gloss and resistance to condensation or Mo41 82 -- 21~3563 solvent, thus enabling it to be reused as a coating composition for the same purpose without modification.
Example 2 (not according to the invention) The same coating composition as in Example 1 was applied by 5 spraying.
In this example reconcentration was performed solely by ultrafiltration. The membrane was a polyacrylonitrile having an exclusion limit of 50,000 g/mol, as in the ull,~rilll~lion stage of Example 1.
The working pressure was 4 bar. The pH was held constant at 8.8 10 by the addition of dimethylethanolamine. Reconce"l~alion had to be terminated when the solids content reached only 48% because the permeant flow had dropped to 0.6 I/m21h.
At this time 40% of the amino resin used had passed through the membrane. Even after the addition of amino resin to make for its loss in 15 the permeant, it was not possible to prepare coatings having the gloss, solvent resistance and hardness of the original coating. Thus, it was not possible to use the retentate for the preparation of coating compositions without loss of properties.
Although the invention has been described in detail in the 20 foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Mo41 82
in water) 0.2% cross-linking agent (Fluorad FC 129.3 M) The coating was diluted with water to a spraying viscosity of 35 s 5 (DlN-4-beaker/23C) before spray application. The solids content was about 59% and the pH was about 8.8.
Demineralized water was used as the booth water.
The solids content of the booth water/overspray mixture was 5%
when the spraying operation was complete.
A polyacrylonitrile membrane having an exclusion limit of 50,000 g/mol was used in the ull,drillralion stage for preconcentration.
Ultrafiltration was continued at a pressure of 4 bar until the solids content of the retentate was 30%.
Reconcentration of the combined permeants from the ull,ariill~lion 15 and nanofiltration stages took place in the reverse osmosis stage using a modified polyamide membrane capable of over 98% retention of common salt at a pressure of 30 bar. The permeant, containing less than 0.1%
organics, was reused as the booth water in the next spraying operation.
The combined retentates from ulll~rill,~lion and reverse osmosis 20 were reconcentrated to the original solids content of 59% in the nanofiltration stage which took place in parallel with ulllarilll~lion and reverse osmosis. A polypiperazinamide membrane having an exclusion limit of 1,000 g/mol was used at a pressure of 20 bar. The nanofiltration permeant was mixed with the ull,~rill,alion permeant and supplied to the 25 reverse osmosis unit.
The resulting coating composition was identical to the original coating composition in all properties relating to coating technology, including hardness, drying rate, gloss and resistance to condensation or Mo41 82 -- 21~3563 solvent, thus enabling it to be reused as a coating composition for the same purpose without modification.
Example 2 (not according to the invention) The same coating composition as in Example 1 was applied by 5 spraying.
In this example reconcentration was performed solely by ultrafiltration. The membrane was a polyacrylonitrile having an exclusion limit of 50,000 g/mol, as in the ull,~rilll~lion stage of Example 1.
The working pressure was 4 bar. The pH was held constant at 8.8 10 by the addition of dimethylethanolamine. Reconce"l~alion had to be terminated when the solids content reached only 48% because the permeant flow had dropped to 0.6 I/m21h.
At this time 40% of the amino resin used had passed through the membrane. Even after the addition of amino resin to make for its loss in 15 the permeant, it was not possible to prepare coatings having the gloss, solvent resistance and hardness of the original coating. Thus, it was not possible to use the retentate for the preparation of coating compositions without loss of properties.
Although the invention has been described in detail in the 20 foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Mo41 82
Claims (6)
1. A multi-stage membrane filtration process for reconcentrating the overspray from a one-component, aqueous coating composition containing high molecular weight components having a weight average molecular weight of at least 2000 and at least 5% by weight, based on the total weight of the organic components of the coating composition, of a low molecular weight component having a weight average molecular weight of less than 2000, that has been diluted with spray booth water from spray booths having wet flushing to form a booth/water overspray mixture, said process comprising a) preconcentrating the booth water/overspray mixture in an ultrafitration unit to obtain a first retentate containing high molecular weight components and a first permeant containing water and at least a portion of the low molecular weight components, b) treating said first permeant and the third permeant obtained in step c) below in a reverse osmosis unit to obtain a second permeant containing essentially pure water for recycle as booth water and a retentate containing low molecular weight components, c) treating said first and second retentates in a nanofiltration unit to obtain a third permeant containing water and a minor portion of low molecular weight components and a third retentate which largely corresponds in composition and concentration to said one-component, aqueous coating composition.
2. The process of Claim 1 which comprises maintaining a differential pressure of 1 to 10 bar in the ultrafiltration unit, and maintaining a differential pressure of 12 to 40 bar in the nanofiltration unit.
3. The process of Claim 1 which comprises introducing said booth water/overspray mixture into a first intermediate tank before it is preconcentrated in accordance with step a).
4. The process of Claim 1 which comprises introducing said second permeant into a second intermediate tank before it is recycled as boot water.
5. The process of Claim 1 which comprises introducing said first and third retentates (4) and (7) into a third intermediate tank (14) before they are treated in accordance with step c).
6. The process of Claim 1 which comprises introducing said third permeant into a fourth intermediate tank before it is treated together with said first permeant in accordance with step b).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE4406952A DE4406952A1 (en) | 1994-03-03 | 1994-03-03 | Process for concentrating paint overspray |
DEP4406952.9 | 1994-03-03 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2143563A1 true CA2143563A1 (en) | 1995-09-04 |
Family
ID=6511697
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002143563A Abandoned CA2143563A1 (en) | 1994-03-03 | 1995-02-28 | Process for reconcentrating overspray from one-component coating compositions |
Country Status (9)
Country | Link |
---|---|
US (1) | US5490939A (en) |
EP (1) | EP0675080B1 (en) |
JP (1) | JPH07289855A (en) |
KR (1) | KR100363804B1 (en) |
AT (1) | ATE154337T1 (en) |
CA (1) | CA2143563A1 (en) |
DE (2) | DE4406952A1 (en) |
DK (1) | DK0675080T3 (en) |
ES (1) | ES2104435T3 (en) |
Families Citing this family (73)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FI960506A0 (en) | 1996-02-05 | 1996-02-05 | Veikko Jolkin | Foerfarande Foer behandling av avfallsvatten |
WO1998028066A1 (en) * | 1996-12-20 | 1998-07-02 | Usf Filtration And Separations Group, Inc. | Scouring method |
GB9703075D0 (en) * | 1997-02-14 | 1997-04-02 | Anglian Water Services Ltd | Water treatment |
US5836321A (en) * | 1997-04-07 | 1998-11-17 | Chrysler Corporation | Process of recycling a water laden solvent which was used to purge a point supply line of a paint sprayer |
EP0901988A1 (en) * | 1997-08-27 | 1999-03-17 | PPG Industries Lacke GmbH | Process for treating circulating water from spray booths using liquid washing |
KR20010040378A (en) | 1998-01-28 | 2001-05-15 | 어웨어 케미칼즈 엘.엘.씨. | Method for treating circulating water from an enamelling line |
US6019902A (en) * | 1998-04-03 | 2000-02-01 | Durr Environmental, Inc. | Fluid recovery system |
AUPP521298A0 (en) * | 1998-08-12 | 1998-09-03 | Life Therapeutics Limited | Purification of fibrinogen |
US20050224355A1 (en) * | 1999-12-23 | 2005-10-13 | Brendon Conlan | Removal of biological contaminants |
AUPP790898A0 (en) | 1998-12-23 | 1999-01-28 | Life Therapeutics Limited | Renal dialysis |
AUPP790698A0 (en) * | 1998-12-23 | 1999-01-28 | Life Therapeutics Limited | Separation of microorganisms |
FR2789328B1 (en) * | 1999-02-04 | 2001-03-02 | Far | PROCESS FOR PURIFYING WATER CONTAINING SURFACTANT AGENTS BY SUCCESSIVE TANGENTIAL FILTRATIONS AND INSTALLATION FOR IMPLEMENTING THE PROCESS |
US7077942B1 (en) * | 1999-12-23 | 2006-07-18 | Gradipore Limited | Removal of biological contaminants |
AUPQ691400A0 (en) * | 2000-04-14 | 2000-05-11 | Life Therapeutics Limited | Separation of micromolecules |
AUPQ697300A0 (en) * | 2000-04-18 | 2000-05-11 | Life Therapeutics Limited | Separation apparatus |
ATE449200T1 (en) | 2000-04-18 | 2009-12-15 | Gradipore Ltd | SEPARATION AND TREATMENT OF SAMPLES BY ELECTROPHORESIS |
JP2002079153A (en) * | 2000-09-04 | 2002-03-19 | Nippon Paint Co Ltd | Operation control method in recycling system fo water based coating material |
US6923896B2 (en) * | 2000-09-22 | 2005-08-02 | The Texas A&M University System | Electrophoresis apparatus and method |
WO2002028516A1 (en) * | 2000-10-06 | 2002-04-11 | Gradipore Limited | Multi-port separation apparatus and method |
AUPR222300A0 (en) * | 2000-12-21 | 2001-01-25 | Life Therapeutics Limited | Electrophoresis device and method |
AUPR421501A0 (en) | 2001-04-04 | 2001-05-03 | U.S. Filter Wastewater Group, Inc. | Potting method |
JP2003047895A (en) * | 2001-08-08 | 2003-02-18 | Nippon Paint Co Ltd | Recycle method of water based intermediate coating material |
AUPR692401A0 (en) | 2001-08-09 | 2001-08-30 | U.S. Filter Wastewater Group, Inc. | Method of cleaning membrane modules |
US7247238B2 (en) * | 2002-02-12 | 2007-07-24 | Siemens Water Technologies Corp. | Poly(ethylene chlorotrifluoroethylene) membranes |
US20030226807A1 (en) * | 2002-05-01 | 2003-12-11 | Jeff Watson | Method and apparatus for treating aqueous process baths and their associated waste streams |
AUPS300602A0 (en) * | 2002-06-18 | 2002-07-11 | U.S. Filter Wastewater Group, Inc. | Methods of minimising the effect of integrity loss in hollow fibre membrane modules |
NZ539349A (en) * | 2002-10-10 | 2006-11-30 | Siemens Water Tech Corp | Filtration systems employing porous or permeable membranes located in a tank or cell open to atmosphere and a backwash method therefor |
AU2002953111A0 (en) * | 2002-12-05 | 2002-12-19 | U. S. Filter Wastewater Group, Inc. | Mixing chamber |
US8268176B2 (en) | 2003-08-29 | 2012-09-18 | Siemens Industry, Inc. | Backwash |
WO2005046849A1 (en) | 2003-11-14 | 2005-05-26 | U.S. Filter Wastewater Group, Inc. | Improved module cleaning method |
US8758621B2 (en) * | 2004-03-26 | 2014-06-24 | Evoqua Water Technologies Llc | Process and apparatus for purifying impure water using microfiltration or ultrafiltration in combination with reverse osmosis |
CA2564007C (en) * | 2004-04-22 | 2011-05-31 | Siemens Water Technologies Corp. | Filtration apparatus comprising a membrane bioreactor and a treatment vessel for digesting organic materials |
CN101052457B (en) * | 2004-08-20 | 2012-07-04 | 西门子工业公司 | Square mbr manifold system |
NZ553596A (en) | 2004-09-07 | 2010-10-29 | Siemens Water Tech Corp | Reduction of backwash liquid waste |
WO2006029456A1 (en) | 2004-09-14 | 2006-03-23 | Siemens Water Technologies Corp. | Methods and apparatus for removing solids from a membrane module |
JP4954880B2 (en) | 2004-09-15 | 2012-06-20 | シーメンス・ウォーター・テクノロジーズ・コーポレーション | Continuously changing ventilation |
US7591950B2 (en) * | 2004-11-02 | 2009-09-22 | Siemens Water Technologies Corp. | Submerged cross-flow filtration |
WO2006047814A1 (en) * | 2004-11-02 | 2006-05-11 | Siemens Water Technologies Corp. | Submerged cross-flow filtration |
WO2006066319A1 (en) | 2004-12-24 | 2006-06-29 | Siemens Water Technologies Corp. | Cleaning in membrane filtration systems |
NZ555987A (en) | 2004-12-24 | 2009-08-28 | Siemens Water Tech Corp | Simple gas scouring method and apparatus |
KR20070097107A (en) * | 2005-01-14 | 2007-10-02 | 지멘스 워터 테크놀로지스 코포레이션 | Filtration system |
NZ562786A (en) | 2005-04-29 | 2010-10-29 | Siemens Water Tech Corp | Chemical clean for membrane filter |
US8858796B2 (en) * | 2005-08-22 | 2014-10-14 | Evoqua Water Technologies Llc | Assembly for water filtration using a tube manifold to minimise backwash |
US7563363B2 (en) * | 2005-10-05 | 2009-07-21 | Siemens Water Technologies Corp. | System for treating wastewater |
US20070138090A1 (en) | 2005-10-05 | 2007-06-21 | Jordan Edward J | Method and apparatus for treating wastewater |
CA2633436C (en) * | 2005-12-19 | 2011-11-01 | Maharani Paints (India) Pvt. Ltd. | Composition and process for conversion of paint sludge into reusable paint |
US8293098B2 (en) | 2006-10-24 | 2012-10-23 | Siemens Industry, Inc. | Infiltration/inflow control for membrane bioreactor |
EP2129629A1 (en) | 2007-04-02 | 2009-12-09 | Siemens Water Technologies Corp. | Improved infiltration/inflow control for membrane bioreactor |
US9764288B2 (en) | 2007-04-04 | 2017-09-19 | Evoqua Water Technologies Llc | Membrane module protection |
US20080296224A1 (en) * | 2007-05-29 | 2008-12-04 | Pumptec, Inc. | Reverse osmosis pump system |
KR101239780B1 (en) | 2007-05-29 | 2013-03-06 | 지멘스 인더스트리 인코포레이티드 | Membrane cleaning with pulsed airlift pump |
US7799218B2 (en) * | 2007-06-29 | 2010-09-21 | Caterpillar Inc | Paint reclamation clarifier system |
KR101614520B1 (en) | 2008-07-24 | 2016-04-21 | 에보쿠아 워터 테크놀로지스 엘엘씨 | Frame system for membrane filtration modules |
CA2734796A1 (en) | 2008-08-20 | 2010-02-25 | Siemens Water Technologies Corp. | Improved membrane system backwash energy efficiency |
US8057681B2 (en) * | 2008-11-26 | 2011-11-15 | Toyota Motor Engineering & Manufacturing North America | Washer bath using centrifuge and ultra filter |
CN102356454B (en) * | 2009-03-31 | 2014-03-26 | 栗田工业株式会社 | Apparatus and method for treating etching solution |
AU2010101488B4 (en) | 2009-06-11 | 2013-05-02 | Evoqua Water Technologies Llc | Methods for cleaning a porous polymeric membrane and a kit for cleaning a porous polymeric membrane |
EP2563501B1 (en) | 2010-04-30 | 2019-05-15 | Evoqua Water Technologies LLC | Fluid flow distribution device |
AU2011305377B2 (en) | 2010-09-24 | 2014-11-20 | Evoqua Water Technologies Llc | Fluid control manifold for membrane filtration system |
WO2013049109A1 (en) | 2011-09-30 | 2013-04-04 | Siemens Industry, Inc. | Isolation valve |
WO2013048801A1 (en) | 2011-09-30 | 2013-04-04 | Siemens Industry, Inc. | Improved manifold arrangement |
US9316216B1 (en) | 2012-03-28 | 2016-04-19 | Pumptec, Inc. | Proportioning pump, control systems and applicator apparatus |
WO2014004645A1 (en) | 2012-06-28 | 2014-01-03 | Siemens Industry, Inc. | A potting method |
DE112013004713T5 (en) | 2012-09-26 | 2015-07-23 | Evoqua Water Technologies Llc | Membrane safety device |
AU2013231145B2 (en) | 2012-09-26 | 2017-08-17 | Evoqua Water Technologies Llc | Membrane potting methods |
AU2013101765A4 (en) | 2012-09-27 | 2016-10-13 | Evoqua Water Technologies Llc | Gas Scouring Apparatus for Immersed Membranes |
JP5960183B2 (en) * | 2013-03-25 | 2016-08-02 | 富士フイルム株式会社 | Method for removing impurities in polymer compound solution |
CN103241805A (en) * | 2013-05-10 | 2013-08-14 | 北京中科润石油技术服务有限公司 | Nanofiltration water treatment method and system |
WO2015050764A1 (en) | 2013-10-02 | 2015-04-09 | Evoqua Water Technologies Llc | A method and device for repairing a membrane filtration module |
WO2017011068A1 (en) | 2015-07-14 | 2017-01-19 | Evoqua Water Technologies Llc | Aeration device for filtration system |
US10760557B1 (en) | 2016-05-06 | 2020-09-01 | Pumptec, Inc. | High efficiency, high pressure pump suitable for remote installations and solar power sources |
US10823160B1 (en) | 2017-01-12 | 2020-11-03 | Pumptec Inc. | Compact pump with reduced vibration and reduced thermal degradation |
CN107963748A (en) * | 2017-12-04 | 2018-04-27 | 郑州艾莫弗信息技术有限公司 | A kind of water-base resin produces dedicated wastewater treatment equipment |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2353469B2 (en) * | 1973-10-25 | 1976-03-25 | Fa. Otto Dürr, 7000 Stuttgart | PROCESS FOR PREPARING A PAINT WATER MIXTURE IN PAINTING PLANTS |
DE2945523A1 (en) * | 1979-11-10 | 1981-05-21 | Daimler-Benz Ag, 7000 Stuttgart | METHOD FOR CLEANING EXHAUST AIR FROM PAINT SPRAYING CABINS |
JPS56141875A (en) * | 1980-04-08 | 1981-11-05 | Dainippon Toryo Co Ltd | Paint recovering and reusing method |
DE3332457C2 (en) * | 1983-09-08 | 1986-06-05 | Wolfgang Dipl.-Ing. 8941 Memmingerberg Richter | Process for recovering paint material from the overspray produced during spray painting and arrangement for carrying out the process |
DE3428300C2 (en) * | 1984-08-01 | 1993-10-14 | Eisenmann Kg Maschbau | Process for the recovery of water-based paints |
CH680710A5 (en) * | 1989-12-22 | 1992-10-30 | Unicolor Ag | |
US5092928A (en) * | 1990-05-25 | 1992-03-03 | Caterpillar Inc. | Process for recovering paint overspray particles |
US5282970A (en) * | 1991-04-09 | 1994-02-01 | Unicolor Ag | Method for environmentally benign paint spraying with an air-drying lacquer dissolved, emulgated or dispersed in water |
US5393390A (en) * | 1991-05-08 | 1995-02-28 | Akzo Nobel Nv | Treatment and recycling of overspray from the spray application of waterborne coatings |
DE4126483A1 (en) * | 1991-08-10 | 1993-02-11 | Bayer Ag | METHOD FOR CONCENTRATING LATEX DISPERSIONS |
DE4133130A1 (en) * | 1991-10-05 | 1993-04-08 | Herberts Gmbh | METHOD FOR RECOVERY OF THE OVERSPRAY OF AQUEOUS COATING AGENTS ON THE SPRAY APPLICATION IN SPRAYING CABINS |
DE4202539A1 (en) * | 1992-01-30 | 1993-08-05 | Duerr Gmbh & Co | RECOVERY SYSTEM FOR WATER PAINT SURPLUS |
DE4207383A1 (en) * | 1992-03-09 | 1993-09-16 | Herberts Gmbh | METHOD FOR RECOVERY OF THE OVERSPRAY OF AQUEOUS COATING AGENTS ON THE SPRAY APPLICATION IN SPRAYING CABINS |
DE4213671A1 (en) * | 1992-04-25 | 1993-10-28 | Herberts Gmbh | Process for the recovery of the overspray of aqueous coating agents when spraying in spray booths |
DE4319994A1 (en) * | 1993-06-17 | 1994-12-22 | Bayer Ag | Process for concentration of paint overspray |
-
1994
- 1994-03-03 DE DE4406952A patent/DE4406952A1/en not_active Withdrawn
-
1995
- 1995-02-20 ES ES95102331T patent/ES2104435T3/en not_active Expired - Lifetime
- 1995-02-20 EP EP95102331A patent/EP0675080B1/en not_active Expired - Lifetime
- 1995-02-20 DE DE59500299T patent/DE59500299D1/en not_active Expired - Fee Related
- 1995-02-20 DK DK95102331.6T patent/DK0675080T3/en active
- 1995-02-20 AT AT95102331T patent/ATE154337T1/en not_active IP Right Cessation
- 1995-02-24 US US08/393,646 patent/US5490939A/en not_active Expired - Fee Related
- 1995-02-28 CA CA002143563A patent/CA2143563A1/en not_active Abandoned
- 1995-03-01 JP JP7065304A patent/JPH07289855A/en active Pending
- 1995-03-02 KR KR1019950004244A patent/KR100363804B1/en not_active IP Right Cessation
Also Published As
Publication number | Publication date |
---|---|
KR950031920A (en) | 1995-12-20 |
EP0675080B1 (en) | 1997-06-11 |
DK0675080T3 (en) | 1997-12-15 |
EP0675080A3 (en) | 1996-04-24 |
US5490939A (en) | 1996-02-13 |
JPH07289855A (en) | 1995-11-07 |
DE4406952A1 (en) | 1995-09-07 |
ATE154337T1 (en) | 1997-06-15 |
KR100363804B1 (en) | 2003-02-14 |
DE59500299D1 (en) | 1997-07-17 |
EP0675080A2 (en) | 1995-10-04 |
ES2104435T3 (en) | 1997-10-01 |
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