CS269274B1 - A method for reducing the dustiness of dried products - Google Patents

Abstract

The solution represents a method for reducing the dustiness of dried products by adding nonionic surfactants based on a copolymer of oxirane and methyloxirane on a higher fatty alcohol or on a higher fatty acid or a mixture thereof in an amount of 0.05 to 10% by weight based on the treated product in the form of finely dispersed particles. The higher fatty alcohol contains 8 to 20 carbon atoms in the molecule and 3 to 10 moles of propylene oxide and 4 to 14 moles of ethylene oxide in the molecule. The higher fatty acid used here, technical oleic acid, contains 3 to 10 moles of propylene oxide and 4 to 14 moles of ethylene oxide per molecule.R- 0 (C3H6O)n (C2H40)m H R- C00 (C3H6O)n (C^OJm H R- 0 (C2H4O)m (C3H6O)n H R- COO (C2H4O)m (C^OJn H

Description

The invention relates to a method of reducing the dustiness of chemical products dried in various types of drying equipment, where the resulting product contains a high proportion of dust particles, by applying a nonionic surfactant based on copolymers of oxirane and methyloxirane on a higher fatty alcohol or on a higher fatty acid.

Nowadays, more and more attention is paid to ecology and protection of the living and working environment. This fact has not escaped the production and finalization of powder products.

According to previously known procedures, dustiness reduction is carried out, for example, by granulation, of water-soluble and water-insoluble products.

For example, German patent No. 2,263,968 describes the granulation of water-insoluble vat or diffusion dyes. It is carried out by spraying a highly dispersed dye in powder form onto a fluidized bed. The spray substance is formed by a dispersant, namely lignin sulfonate or sodium dinaphthyl methane disulfonate. The fluidized bed is formed by hot air (70 to 200 °C). The particle size depends on the dwell time.

US Patent No. 1,567,734 describes the preparation of dust-free dye particles in a fluidized bed. The dried dye is fluidized in an air bed and sprayed with an organic solvent or an aqueous dye solution. The useful fraction is then separated, the dust portion being returned to the fluidized bed.

Furthermore, a number of methods for dust-free treatment of powder products are described, consisting in the addition of cohesion agents and dust-binding agents.

As types of substances for cohesion, e.g. dextrin, sorbitol, urea, glucose, lactose, mannose, polyethylene glycol with a molecular weight of over 3,000, polyvinyl alcohol and other substances are described in a number of patents, in an amount of 3 to 5%. Substances for binding dust are surfactants, preferably non-ionic, e.g. block polymers, ethylene oxide - propylene oxide, condensation products of alcohols or phenols with ethylene oxide in an amount of 1 to 10%. .

According to the patent of the Federal Republic of Germany No. 2,654,408, the procedure is that cohesion substances (polyhydroxy compounds) such as dextrin, sorbitol, polyvinyl alcohol in an amount of 10% and dust binding substances of a non-ionic nature soluble in water are added to the solution of the dried product, as well as when sprayed onto the dried product, into which they are mixed.

Further described are methods of performing a dust-free treatment by spraying alkylbenzenes into the dried product with intensive mixing of the powdered product. European patent No. 0 056 160 and German patents Nos. 2 523 096 and 2 931 771 describe a dust-free treatment by adding mineral oil and an emulsifier to the product solution before drying.

The disadvantages of the above processes, for example in granulation, are high equipment requirements, high labor intensity, low equipment capacity and high energy consumption requirements.

Dust reduction based on the cementation of powder particles using liquids sprayed onto the surface of the treated product, thereby creating liquid bridges between the particles, affecting the cohesion of the dye, such as various mineral oils, alkylbenzene, etc., have the disadvantage that they are insoluble in water and only emulsifiable in combination with surfactants.

Mineral oil and/or alkylbenzene not only have an adverse effect on the product itself in aqueous solution, but also other adverse effects, especially ecological. These substances enter wastewater and due to their poor biological degradability, their use is undesirable.

Another disadvantage of products treated in this way is the tendency of some surfactants to diffuse from the surface of the particles into the interior of the particles, so that the dust-free treatment is temporary, or the particles clump due to excessive cementation.

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The above disadvantages are eliminated by the method of reducing the shelf life of products according to the invention, the essence of which consists in applying to the dried or dried particles of the treated product by spraying or by simple addition a nonionic surfactant based on a copolymer of oxirane and methoxyrane on a higher fatty alcohol or on a higher fatty acid, or their mixtures of general formulas,

R - O-(C ₃ H ₆ O) n (C ₂ H ₄ O) mH R - 0-(0^0) m (C^O) n , R - COO(CjHgO) n (C ₂ H ₄ O) mH R - COO (C^O) m (C^HgO) n, where R is an alkyl with a carbon number of Θ to 20, n is a natural number of 3 to 10, m is a natural number of 4 to 14, in an amount of 0.05 to 10% by weight, based on the product to be treated, in the form of finely dispersed particles, which is preferably carried out by spraying with a two-component nozzle, where the propellant gas is air or steam, directly into the drying chamber, pneumatic transport, before or after the cyclones, into the fluidized bed, or this nonionic surfactant is directly mixed into the dried product. '

Powder products treated in this way are free-flowing and dust-free after long-term storage, i.e. after a period longer than 1 year in layers 1.5 m high.

The copolymer of oxirane and methyl oxirane anchored on a fatty alcohol or acid has strong wicking and antistatic effects, which are beneficial for the treated products during non-destructive treatment.

It is known that a number of substances used for dust-free treatment have only limited use, i.e. adding a certain amount of the substance will reduce the dustiness of the product to some extent, but adding more does not reduce the dustiness, the product clumps, or when using surfactants, their amount is limited by strong foaming of the treated products when applying, for example, organic dyes in their solutions.

According to the process of the invention, the reduction of dustiness is directly proportional to the amount of the dosed preparation and inversely proportional to the particle size of the treated product. Products treated in this way foam only slightly in aqueous solutions or suspensions, especially if methyloxirane is bound at the end of the molecule after oxirane in the copolymer molecule. The preparation is soluble in water, the copolymer, on fatty acids is well emulsifiable in water and both of these preparations are well biodegradable. The invention is further described and the effects of the copolymer of oxirane and methyloxirane anchored on a higher fatty alcohol or acid in the treatment of powder products, are demonstrated by examples of its use and the results of tests carried out.

The modified products were evaluated on a device for evaluating the dustiness of bulk materials, which is based on the principle of reducing the transmission of light as it passes through a cuvette where the sample is sprayed. The device graphically records the course of the transmission values T as a function of time t.

The evaluation is performed using these two quantities of transmission T (%) achieved over a certain time t (in sec).

Example 1

Sodium dinaphthyl methane disulfonate was dried in a spray dryer with a capacity of 500 kg/h of dried powder. A vibrofluidic trough was placed behind the dryer, in which 0.4 kg/h of a copolymer of oxirane and methyl oxirane on a higher fatty alcohol with a carbon number of 12 to 15, which contains 5 moles of propylene oxide and 8 moles of ethylene oxide per molecule, was sprayed onto the dried powder. The copolymer was sprayed into a fine mist using air in a two-component nozzle.

The transmission, which is the transmission in % after 10 seconds from the sample being added, was 77.5% for the powder before treatment and 99% for the powder after treatment.

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The value of t$ ₀ , which is the time in seconds required to achieve 90% transmission, was 28 seconds for the powder before treatment and 1 second for the powder after treatment.

Example 2 Sodium a-nitrobenzenesulfonate in the form of a 25% aqueous solution was dried in a spray dryer with a capacity of 100 kg/h of dried powder. During drying, 6 kg/h of a copolymer of oxirane and methyloxirane on a higher fatty alcohol with a carbon number of 12 to 18, which contains 6 moles of propylene oxide and 9 moles of ethylene oxide in the molecule, was dosed into the drying chamber. The copolymer was sprayed into a fine mist using air in a two-component nozzle. The transmittance Τ^θ for the untreated powder was 44% and for the powder after treatment it was 98%. The value t$ ₀ for the untreated powder was not reached-·and for the powder after treatment it was 1 sec.

Example 3 Sodium m-nitrobenzenesulfonate in the form of a 25% aqueous solution was dried in a spray dryer with a capacity of 100 kg/h of dried powder. During drying, 6 kg/h of a copolymer of oxirane and methyloxirane on a higher fatty alcohol with a carbon number of 12 to 18, which contains 6 moles of propylene oxide and 9 moles of ethylene oxide per molecule, was sprayed into the pneumatic conveying pipe transporting the powder to the cyclones. The copolymer was sprayed into a fine mist using air in a two-component nozzle.

The transmission T^ _Q of the untreated powder was 44% and of the treated powder was 97%. The t^qu value of the untreated powder was not reached and of the treated powders was 2 sec.

Example 4

98.5 parts by weight of powdered sodium ethylenediaminetetraacetate were mixed in a laboratory mixer with 1.5 parts by weight of a copolymer of oxirane and methyloxirane on technical oleic acid, which contains 6 moles of propylene oxide and 7 moles of ethylene oxide per molecule. After 10 minutes of mixing, a dust-free treatment was achieved.

The transmission Τ^θ of the untreated powder was 56% and of the treated powder 99.56. The value of t$ ₀ of the untreated powder was 68 sec and of the treated powder 1 sec.

Example 5

The condensate of sulfonated 2-naphthol, phenol, lignosulfonic acids and formaldehyde in the form of a 45.5% aqueous solution, neutralized to pH - 3.5, was dried in a spray dryer. During drying, a copolymer of oxirane and methyloxirane on a higher fatty alcohol with a carbon number of 10 to 14, which contains 9 moles of propylene oxide and 14 moles of ethylene oxide in the molecule, was dosed into the drying chamber. The copolymer was sprayed into a fine mist and dosed in such an amount that it was 1/2% by weight in the resulting product.

The transmission Τ^θ of the untreated powder was 74% and of the treated powder 98%. The t$Q value of the untreated powder was 40 sec and of the treated powder 1 sec.

Example 6 parts by weight of powdered organically and inorganically masked basic chromium(III) sulfate, obtained by reducing a sodium dichromate solution in an acidic medium with a sugar solution, which contains 26% ^Cr2 °3 ^and a fcacity of 45 °Sch, were mixed in a mixing silo with one part by weight of a copolymer of oxirane and methyloxirane on a higher fatty alcohol with a carbon number of 8 to 20, which contains 3 moles of propylene oxide and 5 moles of

CS 269274 Bl ethylene oxide. A non-dusting product useful in leather tanning was obtained. The transmittance Τ^θ for the untreated powder was 65 Ϊ and for the treated powder 97%. The value ΐ^θ for the untreated powder was 60 sec and for the treated powder 2 sec.

Example 7 parts by weight of the azo dye Egacid yellow G were mixed in a conical mixer with rotating screws and 5 parts by weight of copolymers of oxirane and methyloxirane on a higher fatty alcohol with a carbon number of 13 to 15, which contains 7 moles of propylene oxide and 10 moles of ethylene oxide in the molecule. After 20 min. of mixing, a non-dusty product was obtained. The transmission T _1Q of the untreated powder was 58% and of the powder after treatment was 98%. The value of tg ₀ of the untreated powder was 75 sec and of the powder after treatment was 1 sec.

Example 8.

A 1% by weight portion of copolymers of oxirane and methyloxirane on a higher fatty alcohol with a carbon number of 12 to 15, which contains 5 moles of propylene oxide and 8 moles of ethylene oxide per molecule, was mixed with 1% by weight portion of copolymers of oxirane and methyloxirane on technical oleic acid, which contains 6 moles and 7 moles of ethylene oxide per molecule.

parts by weight of the above mixture was mixed in a laboratory mixer with 93 parts by weight of the azo dye Ostazin black VB. After 10 min. of mixing, a dust-free treatment was achieved. The transmission Τ^θ of the untreated powder was 25% and of the treated powder 97%· ,

The t^Q value for the untreated powder was achieved and for the treated powder it was 2 sec.

Claims (1)

SUBJECT OF THE INVENTION Method for reducing the dustiness of products dried in spray fluidized bed, chamber or tunnel dryers and optionally subsequently ground substances, such as organic dyes, derivatives of fatty acids, fatty alcohols, aromatic or aliphatic hydrocarbons and inorganic salts, characterized in that a non-ionic surfactant based on oxirane and methyloxirane copolymers on a higher fatty alcohol, or acid or their mixtures of general formulas is applied to the dried or desiccated product particles R - 0 (C ₃ H ₆ O) n (C ₂ H ₄ O) mH R - 0 (C^O) m (C^O) nH R - COO (C Η O) n (C H O) mH R - COO (C2H4O) m (ΟβΗβΟ) nH, where R is an alkyl with a carbon number of 8 to 20, n is a natural number of 3 to 10, m is a natural number of 4 to 14. In an amount of 0.05 to 10% by weight, based on the treated product, in the form of finely dispersed particles, which is preferably applied by spraying with a two-component nozzle, where the propellant gas is air or steam, directly into the drying chamber, pneumatic transport, before or after the cyclones, into the fluidized bed, or the surfactant is mixed directly into the dried product.