EP1001911A1 - Procede de traitement de liquides de traitement contenant des solvants - Google Patents

Procede de traitement de liquides de traitement contenant des solvants

Info

Publication number
EP1001911A1
EP1001911A1 EP98936427A EP98936427A EP1001911A1 EP 1001911 A1 EP1001911 A1 EP 1001911A1 EP 98936427 A EP98936427 A EP 98936427A EP 98936427 A EP98936427 A EP 98936427A EP 1001911 A1 EP1001911 A1 EP 1001911A1
Authority
EP
European Patent Office
Prior art keywords
ultrafiltration
reverse osmosis
permeate
stage
organic solvents
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.)
Withdrawn
Application number
EP98936427A
Other languages
German (de)
English (en)
Inventor
Dietmar Kascha
Karl Manderscheid
Johannes Lindemann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PPG Industries Lacke GmbH
Original Assignee
PPG Industries Lacke GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by PPG Industries Lacke GmbH filed Critical PPG Industries Lacke GmbH
Priority to EP98936427A priority Critical patent/EP1001911A1/fr
Publication of EP1001911A1 publication Critical patent/EP1001911A1/fr
Withdrawn legal-status Critical Current

Links

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
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by 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
    • B01D61/04—Feed pretreatment
    • 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
    • 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
    • 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
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/145—Ultrafiltration
    • 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
    • C02F1/448—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by pervaporation
    • 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

Definitions

  • the present invention relates- bo- a method of obtaining a solvent-containing concentrate from used rinising liquids from the paint processing industry.
  • the initial rinsing liquids which are used to rinse and clean the paint supply in painting units as a consequence of colour changeover, change of coating material, cleaning, maintenance, etc. contain organic solvents in an amount of 10-50% by weight in deionized water. In the course of the cleaning process the paint supply apparatuses are flushed with deionized water.
  • Used rinsing liquids which are obtained in painting processes in the automotive industry when waterborne paint systems are used, therefore have in general a solids content of 4 - 15% by weight and a proportion of low molecular mass organic solvents of up to 15% by weight, the remainder being deionized water, based on the overall mass of the rinsing liquid.
  • the concepts known and employed to date for the treatment of used rinsing liquid include incineration, distillation and direct introduction of the rinsing liquid into the circuit water of spray booths for the painting process. Because of the high water content of the rinsing liquid, the energy consumption entailed by the first two concepts set out above is very high. In addition, the emissions of environmental pollutants are unacceptably high in the case of incineration and of introduction into the circuit water, and additional costs and hazards arise from the transportation of the rinsing liquid from its site of formation to the site of disposal, which is generally necessary for incineration and distillation. In the case of incineration and of introduction into the circuit water, moreover, valuable substances, such as organic solvents and deionized water, are lost.
  • EP-A-0 675 080 discloses a method of concentrating the overspray produced by wet washing-out in spray booths by means of a multistage membrane filtration.
  • the booth water/overspray mixture to be concentrated is initially concentrated in an ultrafiltration stage by separating it into a retentate and a permeate, which contains low molecular mass constituents.
  • the ultrafiltration permeate is supplied together with a nanofiltration permeate to a reverse osmosis stage.
  • the retentate of the reverse osmosis and the retentate of the ultrafiltration are supplied to a nanofiltration stage, where separation takes place into a retentate and a permeate.
  • the retentate of the nano- filtration corresponds substantially to the aqueous paint employed and can therefore be used for this purpose directly or as a constituent of a paint composition.
  • the permeate of the reverse osmosis can be recycled into the booth water circuit.
  • the object on which the present invention is based is therefore to provide a cost-effective treatment method for solvent-containing rinsing liquids which makes it possible, in particular, to use both the solvents and the process water again.
  • This object is achieved by a method of obtaining a solvent-containig concentrate from used rinising process liquids from the paint processing industry, comprising solids fractions, organic solvents and water, by:
  • the ultrafiltration of the present invention is a membrane separation process which is carried out with membranes having a cutoff point of from 200 to 500,000 Da, preferably from 1000 to 250,000 Da.
  • the pressure difference between entry and exit of the module in the ultrafiltration of the invention is 0.5 - 5 bar, preferably below 1 bar. With this mode of operation it is possible to achieve a permeate flow of from 10 to 80 l/m 2 h, preferably from 15 to 50 l/m 2 h. In this con- text, the permeate flow of the ultrafiltration depends not only on this pressure difference but also, in particular, on the feed temperature.
  • the transmembrane pressure difference in the ultrafiltration of the invention is between 1 - 5 bar.
  • membrane modules are suitable for the ultrafiltration unit employed in the method of the invention, such as cushion modules, plate modules, spiral modules, tubular modules, capillary modules, multi-channel modules or hollow- fibre modules.
  • the membranes can be made of polysulphone, polyacrylo- nitrile, polyolefins such as polypropylene or polyethylene, Teflon, porous carbon, ceramic (such as e.g.
  • modules which have been found to be particularly suitable for the ultrafiltration stage of the invention are multi-channel modules or tubular modules with alumina, silicon carbide, polyvinylidene fluoride and polyacrylonitrile membranes.
  • a process liquid from the paint processing industry can be separated into a concentrate and into a permeate which essentially contains only constituents having a molecular weight of less than 1000 Da, preferably less than 200 Da.
  • the membrane used for the ultrafil- tration stage has a large pore size, corresponding to a cutoff point of 250,000 - 500,000 Da, and is doped with charge carriers, preferably positive charge carriers.
  • a membrane of this kind achieves both a very sharp separation and a very high permeate flow at low differential pressures, between the entry and exit of the module, of less than 1 bar.
  • both the permeate flow and the separation performance are greater at low differential pressures, between entry and exit of the module, of less than 1 bar, than at higher pressures, so that particularly effective separation at especially favourable cost is possible with such a membrane.
  • the ultrafiltration can also be practised in a plurality of stages.
  • the reverse osmosis of the invention is likewise a membrane separation method, using membranes which retain at least 95% by weight, preferably at least 98% by weight and, more preferably, at least 99% by weight of sodium chloride.
  • the transmembrane pressure difference is normally between 15 and 100 bar, preferably between 20 and 60 bar and, more preferably, between 20 and 50 bar. In this case a permeate flow of from 3 to 30 l/m 2 h is achieved.
  • Customary membrane modules are suitable for the reverse osmosis, such as spiral modules, tubular modules, capillary modules and hollow-fibre modules.
  • membrane materials particular care should be taken to ensure that the membranes are resistant to the organic solvents, especially aprotic organic solvents, which become concentrated in the retentate of the reverse osmosis.
  • suitable materials are those described above in connection with the ultrafiltration.
  • Polyamide membranes have been found to be particularly suitable.
  • a permeate which is essentially free of organic solvents is essentially free of organic solvents.
  • "essentially free” means a concentration of organic solvents in the reverse osmosis permeate of less than 0.2% by weight based on the overall mass of the permeate, preferably of less than 0.1% by weight, more preferably of less than 0.05% by weight and, most preferably, of less than 0.01% by weight.
  • the separation can be improved further, if required, by a multistage reverse osmosis method.
  • pervaporation stage a diffusion-controlled membrane separation technique in which a vapour mixture which becomes established above a mixture of liquids is separated as a result of the differing permeability of an appropriate membrane. Continual pumped removal of the vapour on the gas side of the membrane produces a concentration gradient which maintains the diffusion. Pervaporation is particularly suitable for concentrat- ing further the retentate of the reverse osmosis.
  • the method of the invention is particularly suitable for treating used rinsing liquids which are obtained when cleaning and rinsing the paint supply of painting units in the automotive industry.
  • This relates in particular to painting units which process waterborne paint systems.
  • Rinsing liquids which have been found suitable for such painting units comprise, in addition to deionized water, one or more solvents selected from isobutanol, n-butanol, n-propanol, iso- propanol, ethylene glycol monobutyl ether, butyldigly- col and N-methylpyrrolidone .
  • the used rinsing liquids obtained in such operations generally have a solids content of 4 - 15% by weight, a proportion of low molecular mass organic solvents of up to 15% by weight, the remainder being deionized water, based on the overall mass of the rins- ing liquid.
  • the solids fraction is composed essentially of the components of the particular paints used. These components comprise pigments and binders in the range between 2000 and 250,000 Da, and low molecular mass constituents, especially crosslinking agents, which may have a molecular weight of less than 2000 Da.
  • the organic solvents originate mainly from the rinsing liquid and to a small extent from the particular paint system used, or are elimination products of the paint system. The principle of the method of the invention is illustrated in Figure 1.
  • the used rinsing liquid 1 is collected in a tank (not shown) and then passed into an ultrafiltration stage 2 for reprocessing.
  • the ultrafiltration stage the high molecular mass constituents of the rinsing liquid are concentrated in the retentate 3 to a solids content of preferably at least 50% by weight.
  • the retentate 3 of the ultrafiltration is then supplied for re-use 4 - for example, for direct use as paint constituents.
  • the permeate 5 from the ultrafiltration stage 2 is essentially free from constituents of relatively high molecular mass, with a molecular weight of more than 1000 Da, preferably more than 2000 Da, and contains organic solvents and water.
  • This permeate 5 is supplied to a reverse osmosis stage 6 in which the organic solvents in the retentate 7 are concentrated to a concentration of at least 25% by weight, preferably at least 50% by weight, and are supplied for separate use 8 - for example, as initial rinsing liquid.
  • the permeate 9 of the reverse osmosis 6 is essentially pure water and can, for example, be recycled into the rinsing process or else employed for other applications where deionized water is required.
  • a used rinsing liquid having the composition stated in Table 1 was passed from a reservoir, at a reservoir temperature of 20°C, through an ultrafiltration stage for concentration.
  • a tubular module with a ceramic membrane having a cutoff point of 100,000 daltons was employed in the ultrafiltration stage.
  • the rinsing liquid entered the module on the feed side at 3 m 3 /h, the pressure upstream of the module being 2.3 bar and the pressure downstream of the module being 2.0 bar.
  • Ultrafiltration was conducted to a solids content of 50% by weight in the concentrate. The composi- tion of the permeate and of the retentate of the ultrafiltration was determined analytically and is shown in Table 1.
  • the permeate of this ultrafiltration was then supplied to a reverse osmosis stage.
  • a spiral module with a polyamide membrane having a sodium chloride retention of not more than 99.2% was used in the reverse osmosis stage.
  • the ultrafiltration permeate entered on the feed side at 0.75 m 3 /h, the transmembrane pressure difference being 41 bar.
  • the reverse osmosis was conducted up to a solvent concentration of 25% in the concentrate.
  • the composition of the concentrate and of the permeate of the reverse osmosis was determined analytically and is reproduced in Table 1.

Landscapes

  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Nanotechnology (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

Cette invention concerne un procédé permettant d'obtenir un concentré contenant des solvants à partir de liquides de rinçage usagés provenant de l'industrie de traitement de peinture qui comprend des fractions solides, des solvants organiques et de l'eau. Le procédé consiste: a) à séparer le liquide de rinçage (1) par ultrafiltration (2) sous forme d'un retentat (3) et d'un perméat (5); b) à séparer le perméat (5) d'ultrafiltration par osmose inverse (6) sous forme d'un concentré (7) contenant des solvants et d'un perméat (9) qui est sensiblement dépourvu de solvants organiques; et c) à éliminer séparément (4, 8, 10) le retentat (3) d'ultrafiltration, le concentré (7) contenant des solvants provenant de l'osmose inverse (6) et le perméat (9) d'osmose inverse.
EP98936427A 1997-07-17 1998-07-16 Procede de traitement de liquides de traitement contenant des solvants Withdrawn EP1001911A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP98936427A EP1001911A1 (fr) 1997-07-17 1998-07-16 Procede de traitement de liquides de traitement contenant des solvants

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP97112200 1997-07-17
EP97112200A EP0891950A1 (fr) 1997-07-17 1997-07-17 Procédé de traitement de liquides industriels contenant des solvants
PCT/EP1998/004422 WO1999003786A1 (fr) 1997-07-17 1998-07-16 Procede de traitement de liquides de traitement contenant des solvants
EP98936427A EP1001911A1 (fr) 1997-07-17 1998-07-16 Procede de traitement de liquides de traitement contenant des solvants

Publications (1)

Publication Number Publication Date
EP1001911A1 true EP1001911A1 (fr) 2000-05-24

Family

ID=8227071

Family Applications (2)

Application Number Title Priority Date Filing Date
EP97112200A Withdrawn EP0891950A1 (fr) 1997-07-17 1997-07-17 Procédé de traitement de liquides industriels contenant des solvants
EP98936427A Withdrawn EP1001911A1 (fr) 1997-07-17 1998-07-16 Procede de traitement de liquides de traitement contenant des solvants

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP97112200A Withdrawn EP0891950A1 (fr) 1997-07-17 1997-07-17 Procédé de traitement de liquides industriels contenant des solvants

Country Status (3)

Country Link
EP (2) EP0891950A1 (fr)
AU (1) AU8542598A (fr)
WO (1) WO1999003786A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006047681A1 (de) * 2006-10-09 2008-04-10 Lk Metallwaren Gmbh Verfahren und Vorrichtung zur Behandlung von Abwässern einer Metallgießerei
CN116282722A (zh) * 2023-03-28 2023-06-23 上海电气集团股份有限公司 一种水性废溶剂处理系统及其方法

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3663407A (en) * 1971-06-21 1972-05-16 Ppg Industries Inc Treatment of an ultrafiltrate derived from an electrodeposition process by reverse osmosis
BE794656A (fr) * 1972-02-25 1973-05-16 Citroen Sa Procede et installation d'electrodeposition de peinture
US4412922A (en) * 1980-07-02 1983-11-01 Abcor, Inc. Positive-charged ultrafiltration membrane for the separation of cathodic/electrodeposition-paint compositions
JPS5941498A (ja) * 1982-09-02 1984-03-07 Nitto Electric Ind Co Ltd 電着塗料浴の処理方法
DE3840576A1 (de) * 1988-12-01 1990-06-07 Aluminium Walzwerke Singen Vorrichtung zum abtrennen von bestandteilen aus einem fluidgemisch und anschliessendem aufkonzentrieren
DE4133130A1 (de) * 1991-10-05 1993-04-08 Herberts Gmbh Verfahren zur rueckgewinnung des oversprays von waessrigen ueberzugsmitteln beim spritzauftrag in spritzkabinen
DE4202539A1 (de) * 1992-01-30 1993-08-05 Duerr Gmbh & Co Rueckgewinnungsanlage fuer wasserlackueberschuss
DE4225848A1 (de) * 1992-08-05 1994-02-10 Duerr Gmbh & Co Spülvorrichtung
DE19600967C2 (de) * 1996-01-12 1998-06-04 Schweizer Electronic Ag Verfahren zum Auftrennen von aus der Leiterplattenherstellung stammenden organischen Prozeßlösungen

Non-Patent Citations (1)

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Title
See references of WO9903786A1 *

Also Published As

Publication number Publication date
AU8542598A (en) 1999-02-10
WO1999003786A1 (fr) 1999-01-28
EP0891950A1 (fr) 1999-01-20

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