SU971870A1 - Process for removing soap from oil after neutralization - Google Patents

Description

The invention relates to the technology of fats, and more specifically to methods for removing soap from oil after neutralization, and is intended for use in the oil and fat industry of the food industry. Methods are known for removing soap from an oil after neutralization by washing, including treating the settled oil containing less than 0.2% soap with an aqueous electrolyte solution, for example, salt, or condensate, and separating the phases of settling or separation. Second flushing tl is also used. The disadvantage of the known method is that when washing the oil from the soap, a significant amount of wash water with a low concentration of soap is separated and the soap from the oil in this way cannot be completely removed. The most closest to the invention by its technical nature and achieved by pe3yjibTaty is a method including washing the neutralized oil, separating the phases by separating and decomposing the soap left in the oil to free fatty acids, which is carried out with an aqueous solution of citric acid. washing the oil produces washing water in an amount of 8-10 by weight of the oil with a low concentration of soap in it, which requires additional costs for extracting emulsified fat and dissolved soap, and Expensive citric acid is used as a reagent for the decomposition of the soap remaining in the oil. The purpose of the invention is to reduce the cost of the process by increasing the concentration of soap in the wash water and reducing the cost of the reagents. The goal is achieved by the method of removing soap from the oil after neutralization, including washing the neutralized oil, separating the phases by separating and decomposing octaBmerocfl in the soap oil to free fatty acids, washing the oil in two steps, using the first step as washing solution an aqueous electrolyte solution, the amount of which is determined from the calculation of the formation in the aqueous phase of a solution of soap with a concentration of 6-10, and at the second - by a solution of soap, which is formed at the first stage of washing portions and their oils taken along 10-50 in an amount by weight of the oils and soaps decomposition is performed to an aqueous acidic solution of an alkali metal salt of phosphoric or sulfuric kis lots In expedient to use monopotassium phosphate or sodium sulfate as a salt. At the first stage, the neutralized oil is washed with an aqueous electrolyte solution, for example, 0, with a solution of sodium chloride, and the amount of the solution is metered according to the amount of soap in the oil. In the aqueous phase of the mixture, the technologically acceptable maximum concentration of soap is 6-10. The mixture is then treated with a soap solution formed in the first stage of washing the previous batches of oil and taken in an amount of 10-50% by weight of the oil to obtain the optimum amount of the aqueous phase, which after separation of the phases ensures separation of the oil remaining in the oil acceptable for decomposition acidic reagent to free fatty acids. By using aqueous solutions of acid salts of alkali metal and phosphoric or sulfuric acid to decompose the remaining soap in the oil, the reagent costs are reduced because the wholesale price, for example, monosodium phosphate of the brand HCH is 19 times lower than the price of citric acid. The drawing shows a process flow diagram for removing soap from oil during neutralization. The method is carried out as follows. The oil, from which the soap stock is separated by sedimentation during the separation, has the content of soap O ,, 20 and heated to 92-97 ° C, is pumped continuously to the jet ejection mixer 1, to which an aqueous salt solution comes from the pressure tank 2 through the rotameter 3 the mixture then enters the mixer k with an adjustable mixing intensity. In this mixer from the pressure tank 5 through the rotameter 6 enters. soap solution in the amount of 10-50 by weight of oil. In the mixer, the k liquids are mixed with such a degree of intensity that the emulsion of water in the oil does not form, and as a result of the use of a relatively large amount of soap solution, the emulsion obtained in the mixer 1 is destroyed. The mixture of oil and soap solution from the mixer k enters the separator 7 where the phases are separated into an oil containing 0.02-0.0 soap, 6-10% soap solution. The soap solution enters the tank 8, from where the pump 9 is fed into the pressure tank 5) in which there is always a specified amount of soap solution circulating in the washing cycle, and its excess is discharged through the drainage pipeline. The oil from the separator 7 enters the mixer 10, where from the pressure tank 11 through the rotameter 12 enters an aqueous solution of sodium phosphate monosubstituted, the concentration and amount of which is taken depending on the content of soap and oil. In the mixer 10, the aqueous solution is extremely dispersed in the oil, decomposing the soap according to a known reaction. All aqueous solutions are heated to the same temperature (92-97 ° C) as the oil. The mixture of oil with an aqueous solution of sodium phosphate from the mixer 10 enters the tank 13, from which pump 1 is fed for drying. Drying and further processing of the oil is carried out by known methods. The first treatment of the neutralized oil is carried out | t to extract from it the aqueous aqueous electrolyte solution (known washing solution), for example, 0, with a solution of sodium chloride. The second oil treatment is carried out with an additional soap solution containing the same electrolyte. The concentrations of soap and electrolyte in the solution for the second treatment are equal to the concentrations of these substances in the aqueous phase of the mixture after the first treatment. The second treatment is carried out to increase the amount of the aqueous phase of the mixture in order to obtain particles of a soap solution of a rational degree of dispersion (larger particles than those obtained after the first treatment), which after separation of the phases ensures the content of soap 0.02, Soap contained in neutralized oil, dissolves in an aqueous electrolyte solution. During the first treatment, it is necessary to inject the washing solution of the electrolyte in an amount determined from the calculation of the formation in the aqueous phase of a mixture of 6-10% aqueous solution of soap. If the end of the soap's traction in the aqueous phase of the mixture, all other things being equal, is less than 6%, a significant amount of low-fat wash water will be obtained, as in wastewater. The concentration of soap 10 is the threshold for the coagulation of soap in the electrolyte. If you slightly increase the concentration of soap (more than 10), get a neutralized washed oil with the remainder of the soap, which can not be decomposed. The introduction of a soap solution in the amount of 10-50 for the second treatment is explained as follows. A rational degree of dispersion of particles of the optimal cluster of the aqueous phase of the mixture, having a certain external surface, ensures, after separation of the phases, the highest content of soap in the oil. In laboratory testing of the reception and regimes, a different amount of soap solution is introduced, with the results obtained in Table 1 being obtained. 1 (the initial content of soap in the oil is 0.2%). T a b l. and c a 1 Residue content The amount of soap solution for second soap in oil,% treatment by weight of oil,% From the data it can be seen that when entering the soap solution starting with 10, the content of soap residues in oil is reached, which can be completely removed without difficulty . An increase in the number of soap solution above 50% is irrational. When the content of the soap oil is 0.02%, it is advisable to decompose it to fatty acids with relatively cheap acid salts. The acid number of the oil increases within acceptable limits for the refined oil. EXAMPLE 1: Initial oil is obtained after separation of soap stock in the sump when neutralized with an alkali solution of a concentration of 135 g / l. The oil contains 0.19% soap and 0.17% moisture. The acid number of the oil is 0, 26 mg KOH. 100 g of oil is placed in a glass with a capacity of 300 ml, heated to 9b ° C, a ferromagnetic rod sealed in glass is placed in a glass, and the glass is placed on the heated surface of a magnetic stirrer. With stirring, 3.0 ml of a 0.8% sodium chloride solution is added dropwise to the oil. The total mixing time is 10 minutes. A homogeneous in appearance emulsion of an aqueous solution of soap “in oil with a soap concentration of the introductory phase of 6% is obtained. The emulsion is placed in a pressure vessel heated by a thermostat and suspended from an electric motor pulley with a shaft rotation speed of 2 rpm (Warren's motor). The pressure vessel is connected by a flexible tube to a mixer, into which the emulsion enters through a 1.2 mm diameter capillary, mounted tangentially at the bottom of the mixer cylinder. The cylinder of the mixer is heated with water from a thermostat. In the mixer pour 30 ml (30% by weight of the oil) 6 | th soap solution, prepared with a 0.8% aqueous solution of sodium chloride. When the electric motor is turned on, it raises the vessel upward, as a result of which the emulsion swirls evenly into the millet solution in the mixer, passes through its thickness and collects above the solution in the form of oil. The oil leaves the soap solution in the form of individual drops, which over time merge to form an oil layer above the solution. The oil is left in the mixer to stand for

hours, then pipetted into tubes and centrifuged for 5 minutes at a separation factor of 300 q.

The oil is poured into a glass and the content of soap is determined in its sample. 50 gs of centrifuged oil are placed in a beaker, heated to 96 ° C, a ferromagnetic core is placed in the beaker and placed on the surface of a magnetic stirrer. While stirring, 0.25 ml of a 1% aqueous solution of sodium phosphate monosubstituted is added dropwise to the mixture. The oil is stirred for 10 minutes, poured into test tubes and centrifuged for 5 minutes at a separation factor of 300 q. t5 In the centrifuged oil, the presence of soap is determined qualitatively (indicator - phenolphthalein).

In examples 2 and 3, a wash of the starting 20 neutralized oil was carried out using the described laboratory procedure with a change in the amount of C used, an 8% solution of sodium chloride and the concentration of the soap solution. 25

Indicators of the composition and the results of the experiments are presented in table. 2

In the examples -b, various acid salts are used to decompose the soap. The results are shown in Table. 3 The use of the invention makes it possible to exclude equipment for sewage treatment and the cost of their purification from the oil neutralization scheme. The soap solution {6-10%) can be added to soap stock or sold independently, since it is equal in soap concentration to soap stock produced by neutralizing the oil in a soap-alkaline environment. In addition, the proposed method eliminates the use of food (citric acid) for the decomposition of soap in oil.

The cost per ton of oil when using monosodium phosphate is 2.6 kopecks, and citric acid, 1.7 kopecks. With an average processing capacity of 200 tons / day, saving per year will be 7.2 thousand rubles.

Amount of 0.8% NaCl solution used, ml Concentration of soap in the aqueous phase of the mixture after stage I of washing, Concentration of soap in the solution used in stage II of washing,% Content of soap in the washed oil,% Concentration of aqueous solution of NaHJJO j ,% Amount of used 1-solution of MaN, PO, ml 0.25 Quality test for the presence of soap in oil after treatment with a solution

Table 2

Concentration of acid salt solution,%

The content of the remaining soap in the washed oil

High-quality oil testing for the presence of soap in centrifuged oil

Claims (2)

1. A method for removing soap from an oil after neutralization, including washing the neutralized oil, separating the phases by separating and decomposing the remaining oil in the soap to free fatty acids, characterized in that, in order to reduce the cost of method 30 by increasing the concentration of soap in the wash water and reducing the cost of reagents, washing is carried out in two stages; an aqueous electrolyte solution 35 is used as a washing solution at the first stage, the amount of which is determined from the calculation of the concentration of soap in the aqueous phase atsiey 6-10%, and the second - the soap solution, the first obrazovavshims dtape flushing oil previous portions and Table3 1.0 1.0 1.0 0.026 0.026 0.026 Lack of Lack of Laundry Soap Soap taken in an amount of 10-50 by weight of the oil, and the decomposition of the soap is carried out by exposure to an aqueous solution of an alkali metal acid salt and phosphoric or sulfuric acid. 2. The method according to claim 1, about tl and h and h-shu, and the fact that as the salt used monosodium sulfate or sodium phosphate. Sources of information taken into account in the examination 1. Schmidt A. A. Theoretical foundations of the refining of vegetable oils. M., Pishepromizdat, I960, p. Ul-TiS, 229230, 239-2 1. 2. Manual on the technology of production and processing of vegetable oils and fats. T. II, L., VNIIZh, 1973, p. 69-72 (prototype).