FI53662C - EXHAUST SYSTEM FOR IMMEDIATE EXHAUST SYSTEMS - Google Patents

Description

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(45) ^ T ^ (51) Kv.lk. '/ Int.CI. * B 01 D 19/04 g y Q | ^ | | - p | Q (21) Patent application - Patentansökning 2913/72 (22) Application date - Ansöknlngsdag 20.10.72 ^ (23) Start date - Glltighetsdag 20.10.72 (41) Tullut iulkiseksl - Bllvlt offentllg l8.05-73

National Board of Patents and Registration .... ....... „, ......, 1 (44) Date of display and hearing | -

Patent and registration authorities Ansökan utlagd och utl.skrlften publicerad 31 - 03.7 8 (32) (33) (31) Pyydetty etuoikeus — Begärd priorltet i7.ll.7i

Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) P 2157033.2 - (71) Badische Anilin- & Soda-Fabrik Aktiengesellschaft, 6700 Ludvigshafen,

Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) (72) Franz Poschmann, Mannheimer Str. 1 + 0, 6703 Limburgerhof, Wolfram Bergold,

Am Waldrand 26, 6900 Heidelberg, Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) (7 ^) Oy Kolster Ab (5 ^ +) Method for preventing foaming of aqueous systems by emulsions -Förfarande för skumdämpning i vattenhaltiga system medelst emulsioner

The invention relates to a process for preventing the foaming of aqueous systems with emulsions based on the known technical anti-foaming higher alcohols, fatty acids, fatty acid esters and / or paraffins in the presence of surfactants as emulsifiers.

More particularly, the invention relates to a process for preventing the foaming of aqueous systems with emulsions containing C 1 -C 4 alkanols and / or di- or k Olmi-valued alcohols (C 1 -C 4 fatty acid esters and up to ^ 50%, based on the anhydrous components). paraffin oils and / or tea (C12 'C22 fatty acids as anti-foaming agents and anionic, cationic or ionic surfactants known per se as emulsifiers.,

In technical processes, especially those which take place in aqueous media, there are usually interfering foams which are undesirable even because they adversely affect the quality of the final product or slow down the speed of the process or also cause material loss.

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Given the very large number and quality of methods using water and the virtually unlimited variation in the chemical composition of the substances involved, it is clear that the number and quality of defoaming methods and substances recommended so far are very high.

This situation is evident from the exceptionally extensive literature, especially the patent literature. This literature is familiar to the relevant professional in similar fields and therefore does not require special mention; it is discussed in outline below.

To date, all available hydrophobic or only weakly hydrophilic organic compounds have been used as raw materials for antifoaming agents. There are both chemically uniform products and product mixtures in the most diverse compositions. There are organic substances used as such or in a mixture, as well as an aqueous emulsion of such organic substances. In addition, organic solvents are also widely used in order to achieve a good distribution of the emulsifiable substance. Anti-foaming agents often include ionic or non-ionic emulsifiers. Emulsifiers are known in the art as surfactants. They cause spontaneous distribution of basic hydrophobic components. To achieve economically efficient products, emulsifiers are often used for emulsions of the water-in-oil type, as these themselves most often have anti-foaming properties, whereas for emulsifiers which cause opposite emulsions, oil-in-water is not the case. Nonionic emulsifiers are highly preferred because of their relatively low foaming ability and can thus be added to the resulting oil-in-water emulsions as antifoaming components.

The technical literature on the preparation of antifoams usually only describes special compositions for specific foam problems. This is understandable given the large number of variables that may be relevant. The antifoam properties and the antifoam properties of the substrate itself depend on, for example, temperature, pH, foreign matter and impurities present, as well as water conduction, open or closed container flow rate, vessels, pipelines, etc. There are many apparent difficulties here, e.g. the supposedly separate equipment operating in parallel are completely different in terms of foam development. For producers of antifoams, such a compulsion to develop specialty products is not desirable. Rather, the industry strives for the widest possible range of compositions to simplify end use in general, and not least for the largest possible quantities to be prepared.

The object of the present invention was to develop a method for preventing the foaming of aqueous systems which is not only useful for specific purposes but which can be used as widely as possible, whereby the necessary devices can be manufactured as cheaply and in large quantities as possible and above all with the most economical use.

It has been found that my antifoam combinations based on aqueous emulsions consisting of synthetic or natural fatty alcohols, fatty acid esters, optionally fatty acids and paraffins, and surfactants have advantageous properties in a number of systems in which foam formation must be taken into account.

However, arbitrary mixtures of these substances, when emulsified in water, do not in all cases have the desired anti-foaming effect.

It is known to prevent the foaming of aqueous systems by using aqueous emulsions containing alkanols and / or fatty acid esters of dihydric or trihydric alcohols as well as paraffin oil and / or fatty acids as antifoams.

It has now been found that technical progress is achieved when the average particle size of the emulsified water-insoluble substances is U-9.

According to the invention, the starting materials for the emulsions in question are natural or synthetic straight-chain higher alkanols having 12 to 22 carbon atoms or alkanol mixtures. Examples of these alkanols are myristyl alkyl, cetyl alcohol, stearyl alcohol, and synthetic alcohols such as Ziegler-synthetic by oxidation of aluminum alkylene. (C 1 -C 6), (C 6 -C 8) and (C 20 -C 22) alkanols are obtained, as well as (C 1 -C 6) alkanols obtained by known oxo synthesis. alkanols, and mixtures thereof.

In addition to these, fatty acid esters of dihydric or trivalent alcohols which can also completely replace alcohols must also be mentioned as starting materials. The fatty acids on which the esters are based contain from 12 to 22 carbon atoms and include layrylic acid, nyristylic acid, pamitic acid, stearic acid, peanic acid and behenic acid. Preferably palmitic and stearic acids are suitable. Suitable alcohols as the esterification component are divalent or trivalent and are preferably ethylene glycol or glycerin. In addition, the fatty acid esters and diglycerides of said fatty acids are also to be considered as oily components for the purposes of the invention.

The emulsion preferably contains at least 50% of alcohols and / or fatty acid esters, the $ numbers being calculated on the weight of the anhydrous ingredients.

Optionally, the emulsions may still contain up to $ 50 of pure fatty acids and / or paraffin oils to improve properties. For the purposes of the invention, paraffin oils are to be understood as meaning oils which have been defined as such in the literature. A further definition is therefore superfluous, since all liquid paraffin oils of different bases are suitable for the purposes of the invention, provided that their boiling point does not exceed 350 ° C and that their pour point does not exceed 40 ° C.

Said alcohols or fatty acid esters can in principle be used alone for the preparation of an emulsion. However, it is expedient to use a mixture as defined above, since naturally it achieves an even better antifoam effect, because - as already noted above, since these combinations in themselves guarantee the best possible overall effect.

Common anionic, cationic or nonionic surfactants are used to prepare emulsions. Preferably, however, unionic and non-anionic surfactants are used, in particular sodium or ammonium salts of higher fatty acids, such as ammonium oleate or stearate, oxyalkylated alkylphenols, such as p-isooctylphenol, ethylene oxide, oxyethylated unsaturated substances. 40 times oxyethylated castor oil, 80 times oxyethylated whale oil alcohol or multiple, preferably 8-10 times oxyethylated C12-C10 alcohol.

The mixture of substances is mixed with water in a manner known per se, preferably water is 50-80 by weight of the emulsion, this mixing being carried out so that the particle size is 4-9, preferably 5.5-7 → 5 p. The emulsification technique is commonly known to the person concerned. that simple eo-experiments easily lead to the required particle size. Suitably this is achieved e.g. at suitable mixing speeds, these depending on the quality of the combination to be emulsified.

The particle distribution is a normal distribution (Gaussian distribution), and the coefficient of variation is 10-15 i or less. The coefficient of variation then gives the distance between each inflection point of the Gaussian curve and the peak point of the curve as a percentage of the peak value.

A variety of technical uses have been found for the aqueous emulsions used according to the invention, and in particular in all work processes where strong foaming is to be expected. However, the main application of the new method is in the paper industry, especially in the production of paper, the prevention of foaming of the paper fiber suspension and the production of paper coating compositions.

To prevent foaming of aqueous systems, emulsions are added to the liquids to be prevented foaming, preferably in an amount such that about 100 parts to about 0.02 to 0.3, preferably 0.03 to 0.3 parts of the emulsion used according to the invention per 100 parts of foaming agent. Parts are understood to mean parts by weight. · For the purposes of the present invention, a foam-forming substance is to be understood as meaning the anhydrous components of a foaming liquid which, due to their physical properties, cause the formation of foams. These include pure casein, finely divided paper fibers, paper grease, binders, or biological cleaning sludge.

Said applications clearly show that the emulsions according to the invention are completely independent of the pE value of liquids which must be prevented from foaming, since it is known that e.g. the pH of a paper fiber suspension is less than 3 and the pH of the paper coating mass is usually more than 10. it is expected that the emulsions would have different antifoaming effects, which is not shown by the high frequency of action of the emulsions used according to the invention in each of these two applications.

On the basis of selected examples, the method and the effect of the emulsions according to the invention will be described, without the effect in other areas being less good to study.

Example 1

An antifoam agent was prepared as an aqueous emulsion with a dry matter content of 40 of the following components: 33 parts of C 1-4 alcohol, 3 parts of Cc-paraffin, -p 3 parts of white oil (paraffin mixture), 2 parts of stearic acid oxyethylate per 10 mol mol of ethylene oxide .

The average particle size of the emulsion was 3-8 yu. In a circulating pump burst test with 6 liters of a 20 μm foamable casein solution in a device as described in "Das Papier", 13, ((9έΐ), e. 293-301, a foam surface of only 113 cm was obtained. using 0.3% emulsion, calculated on casein. A similar experiment, using a 0.3 μm flowable antifoam based on oleic acid oxyethylate with 3 moles of ethylene oxide (particle size> 10 μm) gave and a 930 em foam surface. A blank test on these 2 devices with the same casein solution gave a 2012 cm foam surface. The pumping cycle time was 3 minutes.

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Example 2

An emulsion was prepared consisting of: 30 parts of C 1-4 alcohol, 10 parts of spindle oil (paraffin oil), 3 parts of 40 moles of ethylene oxide oxyethylated castor oil and 36 parts of water and an average particle size of 6-7 px. This emulsion was homogenized until the average particle size was no more 2-3 ^ u. When testing a foamable paper fiber suspension (20 l), from waste paper, in the previous device at a consistency of 0.1 56, the p 0 value of foaming was obtained as 1750 cm. 10 mg ($ 0.05, based on waste paper) of emulsion 2 having a particle size of 6-7 was used to reduce the foam surface to 213 cm; In contrast, 10 mg of the emulsion of this example gave a foam surface of 695 cm 2. The pumping cycle time in this experiment was 5 minutes »

Example 3

An emulsion paste having a combination of: 25 parts of C 1-8 C 1-4 fatty alcohol, 15 parts of stearic acid, 5 parts of whale fatty alcohol with 25 moles of ethylene oxide and 55 parts of water was prepared by homogenization at 70 °. The average particle size was 4-7 yu.

Highly foaming paint (water content 50 #) containing 100 parts of coating kaolin, 0.3 parts of polyacrylate, 0.15 parts of sodium hydroxide, 4 parts of casein and 11 parts of an aqueous acrylic acid / methacrylate dispersion using a circulating pump for 15 liters amount of paint 4 liters). In a short time (2 minutes) the pumping speed was 5 liters / min. the empty space of the bottle is filled with foam. With 1 g of the above emulsion, the development of foam could be kept permanently in a foam volume of 2 liters. Example 4

In one sulfite cellulose process, pulp sorting could only be performed using antifoams. In the absence of such excipients, the cohesive agents were not able to perform as required because the foam bubbles prevented water from passing through the thickening side of the fiber suspension. As a result, the collectors were overloaded after thickening and caused overflow. The method used mainly a solid emulsion paste with 5 fatty acids (stearic acid), $ 25> stearic acid oxyethylate, 70 l of water, 7 53662 foaming agents. This paste had to be diluted to $ 2 before use, which was advantageous for the intended use. The particle size was over 10 yu. To prevent foaming, it was necessary to add 0.21 56 emulsions (<0.07 i> solids) of the required amount, based on cellulose, without achieving optimal anti-foaming.

In contrast, a low-viscosity, cold-dilutable emulsion of 20 L of C 1 -C 4 fatty alcohol, 2 of ammonium stearate, 78 of water, with an average particle size of 5 μm, achieved excellent anti-foaming by adding 0.1 l (<0.022 i »fixed). The antifoams had a sufficient after-effect so that no more foam was detectable in the waste solution as before.

Example 5 When sour milk whey was used on Tornia utilis, the fermentation product came into contact with the air with a strong foam which could not be lost by conventional methods. To prevent overflow, a defoamer and a relatively low dosage had to be added so as not to disturb the yeast culture. An emulsion of 28 μl of nutrients, 12 l of lauryl alcohol, 3 l of ammonium oleate, 67 l of water and a particle size of 4-6 yU showed good resistance to yeast by the addition of 0.3 l (0.1 l of solid) and gave good foam prevention. The finer emulsion, 2.3 yu in particle size, was ineffective at 0.6 ^ (<0.2 based on solid).

Example 6

In a biological, municipal water treatment plant, where the water to be clarified contained up to 1 to 6 purification sludge, a large amount of foam was generated during the air treatment phase, which caused intolerable effects on its environment during stormy weather. These disturbances were overcome by the addition of an emulsion of 26 .mu.l of .alpha.-alcohol, 4 .mu.l of paraffin oil, 3 .mu.l of oleic acid oxyethylate with 8 moles of AlO and 63 .mu.l of water and an average particle size of 6. this emulsion at 1/6 dilution was added to the influx at 3 ml / m 2 doses at 8 53662 with foaming. This was followed by a strange change in the structure of the foam. Until now, the small-bubble, tightly held foam became inhomogeneous with respect to the bubbles. The large bubbles suddenly disintegrated, causing the cohesiveness and stability to be disrupted. However, when the particle size was reduced to an average of 3 yu, the emulsion had to be added 3- to 4-fold in an amount to achieve approximately the same effect.