DD292612A5 - PROCESS FOR CUTTING OIL-IN-WATER EMULSIONS - Google Patents

Abstract

Process for the cleavage of OEl-in-water emulsions, the z. As incurred in compressor stations, in the water-steam-condensate cycle, in the mechanical processing of metals or in slaughterhouses. For this purpose, the emulsion is a highly branched, high molecular weight poly (dimethyldiallyl-ammonium chloride) with small amounts of low molecular weight products in concentration from 1 to 5 000 mg / l added as an aqueous solution at temperatures of 293 to 343 K. This results in a complete creaming of the OElphase with a very low Restoelgehalt the water phase, which is technologically easy to separate. {OEl-in-water emulsion; Polydimethyl diallyl ammonium chloride; creaming; oil phase; Cleavage; Split off}

Description

Field of application of the invention

The process can be used in any operation in which oil-in-water emulsions are produced, such as e.g. in compressor stations, in the water-steam-condensate cycle, in the mechanical treatment of metals, such as cutting, drilling, degreasing of metal surfaces or in slaughterhouses or carcass processing plants.

Characteristic of bekannton state of the art

For the splitting of oil-in-water emulsions a number of methods are known. Thus, the cleavage can be done by simple supply of mechanical, thermal or electrical energy. However, these methods can not be used for the harmless removal of stable emulsions. In the thermal cleavage in the true sense of the water content of the emulsion is evaporated, but this process is very energy consuming. The cleavage by membrane filtration gives a filtrate with a certain residual oil content and an oil-water mixture with increased oil content. The disadvantage is that a complete separation of the emulsion is not possible, the concentrate then welter must be disposed of and the membrane surfaces must be thoroughly cleaned in certain Abständon. In the so-called chemical cleavage method, the refraction of the emulsion is achieved by addition of salts or salt mixtures or of acids with subsequent heating. The disadvantage is that large amounts of salt, namely up to 10%, are needed, and that in the case of acid addition, a subsequent neutralization step is required. In both processes, corrosion phenomena on the equipment must be taken into account, and in both processes results in an aqueous phase with a high salt content and a relatively high residual oil content. The salt or acid cleavage can also be combined in a multi-stage process with flocculation by inorganic primary flocculants (eg, iron or aluminum salts). In this case, part of the oil is bound to the forming hydroxide sludge. The disadvantage is that the process runs over at least two stages, that the pH value must be set precisely and that, in addition, a considerable amount of difficultly dewaterable hydroxide sludge is obtained. It is also known to carry out the emulsion breaking by splitting agent and adsorption of the released oil to solid release agent such. B. fumed silica. The disadvantage is that the volume of the oil phase significantly increased by the formation of a solid oil cake, which must also be disposed of further. The energetic destruction of the emulsion by combustion is extremely energy consuming and generally possible only with additional fuels. Biological processes such as composting are very possible. Biological processes such as composting are very time consuming and therefore not suitable for larger amounts of emulsion. The orderly landfill is not economical because of the possible utilization of spent emulsions and pollutes the environment.

Also known are processes for the cleavage of oil-in-water emulsions, in which the creaming is achieved by the addition of water-soluble polymers. Examples of these are US Pat. No. 3,687,845, which, however, achieves only partial creaming by addition of anionic polyelectrolytes, US Pat. No. 3,585,148, in which cationic copolymers are recommended, and US Pat. No. 3,830,735, in which cationic derivatives of polyvinyl alcohols are used. All of these methods have the disadvantage that they are not highly effective Trennprozesso represent and not universally applicable to all oil-in-water emulsions. Moreover, the application is bound to specific pH ranges (US Pat. No. 3,585,148) or requires the use of relatively large amounts of the polymer (US Pat. No. 3,830,735). It has therefore been attempted to achieve an optimization in that the framing with cationic polyelectrolytes in the presence of zinc chloride (US Patent 3591520) and of iron or aluminum salts and / or silica sol is carried out (US-PS 3691086). The disadvantage of this method is that the aqueous phase is charged with a high salt content or that in addition result in significant amounts of sludge whose separation and drainage require additional technological stages and make the process more expensive. DD-PS 226481 recommends the use of poly (dimethyldiallylammonium chloride) with molar masses> 40000 g / mol (poly-DMDAAC). This method has the disadvantage that the residual oil contents are still too high and the amounts used are relatively high. The creaming is too slow.

Zl ^ l of the invention

The object of the invention is to develop a process for the cleavage of oil-in-water emulsions in which the organic substances of the oil phase can be largely completely recovered in an economically favorable manner and wherein a sludge-free aqueous phase is formed whose proportions of inorganic Salts far below the usual inlet values of the receiving water and is characterized by a very low residual oil content. It is envisaged that by the method, the oil creamed and thus can be separated.

Explanation of the essence of the invention

The object of the invention is a process for the cleavage of oil-in-water emulsion, which results in a complete creaming of the oil phase by adding a suitable water-soluble polymer.

According to the invention the object is achieved in that the emulsion cleavage in an oil and a water phase by adding water-soluble, highly branched, high molecular weight poly-dimethyl-diallyl ammonium chloride (poly DMDAAC) with low levels of low molecular weight products (poly-Dv) prepared by copolymerization of Dimethyl diallylammoniumctiiorid with a polyfunctional vinyl polymers, takes place.

It is preferably suitable for this purpose (DMDAAC) with 0.1 to 3.0 mol% of a crosslinking comonomer, eg. For example, methyl triallyl ammonium chloride or tetraallyl ammonium chloride. The emulsion cleavage takes place at temperatures of 293 to 343 K. Here, the pH of the emulsion can be chosen arbitrarily.

The polymer is added to the emulsion as an aqueous solution in amounts of 1 to 5000 mg / l and mixed with the emulsion.

The amount to be used depends on the oil content of the emulsion and its stability.

Based on the oil content, 0.1 to 10% by mass of polymers are used.

The recovery of the oil phase can after dor creaming by Beliobige, simple separation methods, eg. B. by means of a container overflow.

The process is a highly effective separation process applicable to the cleavage of all so-called mechanical emulsions and all emulsions stabilized with anionic, nonionic or ampholytic emulsifiers or combinations thereof.

In this case, the oily phase may be any water-insoluble compound and other additives such. As antioxidants.

The process can be used advantageously for emulsions which contain no or only small amounts of suspended, poorly sedimenting solids.

Compared to other polyelectrolytes, the amounts used and the residual oil content of the water phase are significantly lower, the optical permeability of the water phase better.

The recovery of the oil phase can be carried out by any simple separation ancestors, for. B. by means of a container overflow.

In some cases, a shortening of the creaming time can be achieved if pre-cleavage is carried out by adding aqueous salt solutions of sodium chloride, calcium chloride, magnesium chloride, magnesium sulfate, aluminum sulfate, iron-3-chloride or a silicate prior to the addition of the water-soluble polymer.

For a more detailed explanation of the explanations, the following examples are given.

embodiments

In all Aufrahmversuchen was first 10s intensive mixing of Aufrahmmittels with the emulsion, anschliessenbd was stirred at about 10U / min for 45 minutes and then carried out the phase separation. Subsequently, the light transmittance D of the aqueous phase in 1 cm layer thickness and the residual oil content Cöi the aqueous phase were determined.

example 1

The results of comparative measurements on different polyelectrolytes are summarized in Table 1. The creaming trials were conducted on a spent drilling oil emulsion having an oil content of 3% by volume and 293K.

Table 1:

No. polymer product added amount D cni mg / l % mg / l Copolymer 83% 1 Acrylamide 17% MTMMS 400 72 105 according to US-PS 3691086 Copolymer 75% 400 69 105 2 Acrylamide 25% dimethyl diallyl dimethyl ammonium chloride according to US-PS 3585148 Cationic polyvinyl 400 5.0 119 3 alcohol according to US Pat. No. 3,830,735 Poly-DMDAAC according to DD-PS 226481 400 81 83 4 Poly-D-v with 0.5 to 400 94 36 5 3.0 mole% methyl triallyl ammonium chloride

Example 2

The creaming trials were carried out with a spent drilling oil emulsion having an oil content of 3% by volume and are included in Table 2.

Table 2: added amount D% Poly-DMDAAC Poly-D-v Cöimg / I Poly-D No. mg / l after DD-PS Poly-DMDAAC 226481 after DD-PS 56 71 226481 250 100 75 80 420 88 1 200 79 91 100 44 2 30Ü 81 94 89 36 3 400 83 4

Example 3

A waste oil emulsion (oil content 5 vol .-%), which was used as a cooling lubricant in a lathe, was framed in comparison with PoIy-DMDAAC according to DD-PS 226481 and poly-D-v. The additional amount bed day 100mg / l. The light transmittance D was 64% for poly-DMDAAC and 83% for poly-D-v.

Example 4

A used oil emulsion (oil content 10Vol .-%, 293K) was treated at 2O ⁰ C comparative with poly-DMDAAC and poly-Dv. When using 150 mg / l poly-DMDAAC, D was determined to be 80%. When 100mg / l poly-Dv was used, D was determined to be 83%.

Example 5

A lecithin water from the production of vegetable oils with 10000 mg / l of emulsifiable substance was treated with amounts of poly-D-v.

Tabello 3:

Poly-D-v D

mg / 1%

100 0

200 12

500 60

1000 82

Example 6

1 m ^{3 of} a spent waste oil emulsion was mixed with 82 g of poly-Dv. The mixing was carried out by blowing in air or steam. After 180 minutes, the air or steam supply was turned off. After 240min the creaming was over. The creamed oil phase was withdrawn via an overflow. The aqueous phase had a residual oil content of 40 mg / l.

Example 7

An oily condensate from an industrial power plant was treated at 343K with poly-DMDAAC and poly-D-v. To achieve a light transmission D of 88%, 500 mg / l poly-DMDAAC or 100 mg / l poly-D-v were required.

Example 8

One liter of drilling oil emulsion (oil content 5.5% by volume) at 293K350 mg / l poly-D-v was added, thoroughly mixed and stirred for 40 minutes. Thereafter, the emulsion completely creamed within 4 hours. D = 90%, Cöi = 51 mg / l. On the other hand, if 25 ml of a 10% magnesium chloride solution are initially added to the emulsion, the mixture is stirred for 20 minutes, then 350 mg / l poly-D-v are added and stirring is continued for another 20 minutes, then the emulsion is completely creamed after 2 hours. D = 91%, Cöi% 49mg / l.

Comparable values for D and Cöi at halved shortening time were obtained with the addition of 25 ml of a 10% solution of sodium chloride, magnesium sulfate, calcium chloride, aluminum sulfate, iron-3-chloride or a water-soluble silicate.

Example 9

An oil-containing rinse water (oil content 0.1% by volume) with a pH of 1 was treated with 1 mg / l poly-D-v. Thereafter, the residual oil content was 43 mg / l.

Example 10

An oil-containing emulsion (oil content 7.5% by volume) having a pH of 14 was treated with 5000 mg / l poly-D-v. Thereafter, the residual oil content was 51 mg / l.

Claims (4)

1. A process for the cleavage of oil-in-water emulsions by addition of water-soluble organic polymers by the phase separation process, characterized in that the emulsion at temperatures of 293 to 343No water-soluble, highly branched, high molecular weight poly (dimethyl-diallyl-ammonium chloride) (poly- DMDAAC) in amounts of from 1 to 5000 mg / l of emulsion or in amounts of from 0.1 to 10% by mass, based on the oil content of the emulsion. 2. The method according to claim 1, characterized in that poly (DMDAAC) is used with a low proportion of low molecular weight products. 3. The method according to claim 1 and 2, characterized in that the poly (DMDAAC) 0.1 to 3.0 mol% of a crosslinking comonomer. 4. The method according to claim 1,2 and 3, characterized in that as crosslinking comonomer methyl triallyl ammonium chloride and / or tetraallyl ammonium chloride is used.