RU2317321C1 - Method of adsorption cleaning of vegetable oils - Google Patents

Abstract

FIELD: oil and fat industry.

SUBSTANCE: proposed method includes heating of oil, mixing with alumo-silicate sorbent and filtration. Used as sorbent is natural "kaolinite-β-quartz" mixture at ratio of 9:1 to 9.8:0.2 ground preliminarily with sodium percarbonate at mass ratio of 8:1 to 12:1 and treated by phosphoric acid solution at concentration of 20-25% taken in the amount of 50-75% of mass of mixture. Sorbent is introduced into oil at temperature of 65-75° C in the amount of 0.2-0.4%; mixing of phases is continued for 20-35 minutes at rate of 0.8-1.0 s^-1.

EFFECT: perfect cleaning of vegetable oil from difficultly hydrated phosphatides; reduced acid number and color index; reduced content of oxidation promoters.

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Description

FIELD OF TECHNOLOGY

The invention relates to the oil industry and can be used for the adsorption purification of vegetable oils from difficultly hydratable phosphatides and to reduce the content of coloring substances and free fatty acids in oils.

BACKGROUND

Vegetable oils, in order to increase antioxidant properties and facilitate their processing at the enterprises of the oil and fat industry, must be preliminarily purified from the accompanying substances: phosphatides, free fatty acids (FFA) and coloring components of the pigment complex. Thus, difficult to hydrate phosphorus compounds, despite their nutritional value, impede the process of phase separation during oil neutralization and deodorization, prevent hydrogenation by poisoning the catalyst, and the excess of FFA oil negatively affects its stability over time.

A known method of purification of oils and fats by introducing into them a sorbent based on activated clays containing 50-90% kaolinite [A.S. USSR 491688, MKI S11V 3/10. // Schmidt A.A., Askinazi A.I., Levinson S.Z. et al. 08/20/73; publ. in B.I., 1975, No. 41]. The particle size distribution of the sorbent is characterized in that 90% of its particles have a size of 0.25-1.00 mm and not more than 10% of the particles form a fraction of up to 0.25 mm. The disadvantages of this method include the high consumption of the sorbent (oil: sorbent ratio is from 1: 0.5 to 1: 3) and the implementation of the process from the solvent medium. Moreover, for individual oils, characterized initially by a high content of phosphatides (for example, flaxseed), it is not possible to achieve a reduction in the concentration of the latter by more than 4 times during the cleaning process.

A known method of purification of oils from difficultly hydratable phosphatides (TF) by mixing the oil at 50-90 ° C with a solid acid reagent (CR) obtained by heat treatment of phosphoric acid (FC) synthetic silicates and aluminosilicate sorbents (AC) - silica gel, diatomite, kieselguhr co the average particle size of 0.1-0.2 mm, followed by the neutralization of oils with sodium hydroxide solutions [A.S. USSR 1065470, MKI S11V 3/04. // Askinazi A.I., Melamud N.L., Kalasheva N.A. et al. Decl. 12/04/81; publ. in B.I., 1984, No. 1]. The effect is achieved by the introduction of Raman in the amount of only 0.01-0.10% by weight of fat. However, the disadvantage of this method is the need for additional purification of the oil with alkali solutions (according to the known scheme) or the addition of 2% activated bleaching clay after treatment with the specified KR.

There is also a method for removing contaminants from oils on an amorphous hydrogel of silicon dioxide (SiO ₂ ), processed by co-grinding with bases Na ₂ CO ₃ , NaHCO ₃ , K ₂ CO ₃ , Ca (OH) ₂ , Mg (OH) ₂ , NaOH, KOH, their mixtures or solutions [Pat. USA 5252762, MKI ⁵ C11B 7/00. // Denton Dean A. Decl. 04/03/91; publ. 10/12/93; NKI 553/196]. The amount of sorbent in terms of dry matter is 0.005-5.0% by weight of the oil. The disadvantages of the method are the high cost of the specified sorbent and the implementation of the process at a temperature of 100 ° C, which requires additional energy consumption and, in addition, can lead to undesirable structural changes in food triglycerides.

The closest technical solution for the totality of features, i.e. the prototype is a method of adsorption purification of vegetable oils using a finely dispersed sorbent (1-15 microns) obtained from hydrofluoric acid and aluminum hydroxide and including, wt.%: silicon dioxide 35.0-44.5; aluminum compounds (in terms of Al ₂ O ₃ ) 0.5-10.0; water - the rest [Pat. Russia 2245902, IPC ⁷ С11В 3/00, С11В 3/10. // Pyatachkov A.A., Akaeva T.K., Bederdinov R.A. et al. 03/11/03; publ. in B.I., 2005, No. 4]. The method involves treating the oil for 20-30 minutes at a temperature of 90-120 ° C and a vacuum of at least 8 kPa in the presence of 0.2-2.0 wt.% Sorbent and separating the latter together with impurities by filtration.

The disadvantages of the prototype is to achieve an effect at elevated temperatures of oil processing (90-120 ° C), which requires additional energy consumption and can lead to undesirable changes in the structure of oil fatty acids, as well as the need to create a vacuum of 8 kPa and a fairly high sorbent consumption.

SUMMARY OF THE INVENTION

The objective of the invention is to develop a cost-effective method of adsorption purification of vegetable oils, providing improved oil quality due to the extraction of difficult-to-hydrate phosphatides, free fatty acids and dyes from it.

The problem is solved in that the method of adsorptive purification of vegetable oils involves heating the oil, mixing with an aluminosilicate sorbent and filtering, while using a natural mixture of kaolinite-β-quartz in a ratio of 9: 1 ÷ 9.8: 0.2, previously crushed with sodium percarbonate at a mass ratio of 8: 1 ÷ 12: 1 and treated with phosphoric acid solutions with a concentration of 20-25%, taken in an amount of 50-75% by weight of the mixture, while the sorbent is introduced into the oil at a temperature of 65-75 ° C in the amount of 0.2-0.4%, and the mixing of the phases is carried out they last 20-25 minutes with an intensity of 0.8-1.0 s ^-1 . According to the invention, a natural mixture of the following grain composition is used, wt.%: 0.3 ... 1.2 microns - 3-4; 1.2 ... 2.5 microns - 8-9; 2.5 ... 5 microns - 15-17; 5 ... 10 microns - 23-25; 10 ... 20 microns - 33-35; 20 ... 40 microns - 13-15.

The initial natural mixture is a white clay powder, including kaolinite mixed with β-quartz [Prokofiev V.Yu., Razgovorov PB, Smirnov KV et al. // Izv. universities. Chemistry and Chem. technology. 2006.V. 49, issue 12. P.48-52], issued by NPP Industrial Minerals LLC (Samara Region) and having the following characteristics: pH of an aqueous extract 6.0-6.3; mass fraction of moisture 3.8%; mass fraction of impurities soluble in hydrochloric acid, 0.2; mass fraction of water soluble salts of 0.1.

Sodium percarbonate (TU 2144-284-05763441-99 amend. 1.2) - a granular substance of white color; mass fraction of active oxygen 7-10%, mass fraction of sodium carbonate 65%, mass fraction of water - 2.8%; the residue on a sieve with a square cell side of 0.10 mm is 95.6%.

Phosphoric acid (GOST 10678-76) is a clear, colorless liquid with a density of 1.58-1.68 g / cm ³ , without suspended and emulsified particles, diluted before testing with water to a concentration of 20-25%.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

Example 1. 100 g of purified hydrated sunflower oil is heated to 75 ° C and stirred for 25 minutes, with an intensity of 1.0 s ^-1 , at this temperature with AS introduced into the oil in an amount of 0.4 g, then the oil is filtered off under vacuum. filter. As a sorbent, a natural kaolinite-β-quartz mixture is used in a 9: 1 ratio, including particles 0.3 ... 1.2 μm - 3%, 1.2 ... 2.5 μm - 9%, 2.5 ... 5 microns - 17%, 5 ... 10 microns - 23%, 10 ... 20 microns - 35%, 20 ... 40 microns - 13%. The specified natural mixture is pre-crushed with PCN in a mass ratio of 8: 1, treated with a 20% FC solution taken in an amount of 75% by weight of the natural mixture, and dried at 105 ° C.

Example 2. 100 g of purified hydrated sunflower oil is heated to 65 ° C and stirred for 20 minutes, with an intensity of 0.8 s ^-1 , at a given temperature with AS introduced into the oil in an amount of 0.2 g, then the oil is filtered off under vacuum. filter. As a sorbent, a natural mixture of kaolinite-β-quartz is used in a proportion of 9.8: 0.2, including particles 0.3 ... 1.2 μm - 4%, 1.2 ... 2.5 μm - 8% , 2.5 ... 5 microns - 17%, 5 ... 10 microns - 25%, 10 ... 20 microns - 33%, 20 ... 40 microns - 13%. The specified natural mixture is pre-crushed with PCN in a mass ratio of 12: 1, treated with a 25% FC solution taken in an amount of 50% by weight of the natural mixture, and dried at 110 ° C.

Example 3. 100 g of purified linseed oil is heated to 70 ° C and stirred for 20 minutes, with an intensity of 1.0 s ^-1 , at a given temperature with AS introduced into the oil in an amount of 0.3 g, then the oil is filtered off on a vacuum filter . As a sorbent, a natural mixture of kaolinite-β-quartz is used in a proportion of 9.3: 0.7, including particles 0.3 ... 1.2 μm - 4%, 1.2 ... 2.5 μm - 9% , 2.5 ... 5 microns - 15%, 5 ... 10 microns - 24%, 10 ... 20 microns - 34%, 20 ... 40 microns - 14%. The specified natural mixture is pre-crushed with PCN in a mass ratio of 10: 1, treated with a 20% solution of FC, taken in an amount of 60% by weight of the natural mixture, and dried at 105 ° C.

The main indicators of vegetable oils were determined by standard methods [Arutyunyan N.S., Yanova L.I., Arisheva E.A. et al. Laboratory workshop on technology for processing fat. M .: Agropromizdat, 1991. 160 p.], The content of heavy metals was estimated by the atomic absorption method on a Saturn-3 instrument, and the peroxide number of the oil was also controlled [Kozlov V.A., Kokhova L.V. Commodity research of food products. Ivanovo: ed. IGHTA, 1995. 88 p.]. The data obtained are summarized in a table.

From the data presented in the table it follows that the introduction of 0.4% sorbent into the oil according to the proposed method provides the maximum cleaning effect from TF. The degree of decrease of the acid number of sunflower oil, compared with the prior art, is 1.7 times greater, the color number of 15 mg I _2/100 cm ³ and, further, in the cleaned oil content decreases oxidation promoters: nickel - up to 0.11 mg / kg, copper - up to 0.12 mg / kg; the iron content varies slightly. Using the proposed method allows to achieve a decrease in the mass fraction of TF in linseed oil by 7 times compared to the initial value, as well as to increase, compared with the prototype, the degree of extraction of FFA - 1.6 times, dyes - 9%, heavy metals nickel - 1.4 times, copper - 1.7 times.

Table Indicators Sunflower oil Linseed oil before cleaning peeled before cleaning peeled the proposed method prototype the proposed method prototype example 1 example 2 example 3 Mass fraction of phosphorus-containing substances,%, in terms of stearooleolecithin 0.04 Not detected 0.007 0.011 0,07 0.01 0,03 Acid number, mg KOH / g 0.42 0.19 0.30 0.32 0.64 0.40 0.67 Color number, mg I _2/100 cm ³ twenty fifteen fifteen fifteen 55 25 thirty Peroxide value,% iodine 0.11 0.11 0.10 0.10 0.02 0.02 0,03 The content of heavy metals, mg / kg: nickel 0.27 0.11 0.12 0.14 0.17 0.09 0.13 copper 0.35 0.12 0.15 0.33 0.33 0.11 0.19 gland 0.53 0.56 0.54 0.61 1.20 1.23 1.25

A positive cleaning result on the sorbent, including the addition of PKN in the ratio indicated according to the invention, is not accompanied by a significant change in the peroxide numbers of vegetable oils, which indicates their resistance to oxidation.

The proposed method is economical, since it does not require a significant consumption of sorbent, heating oil above 75 ° C, carrying out the process at low pressure, and provides higher quality vegetable oils suitable for subsequent processing at food industry enterprises.

Claims (2)

1. The method of adsorption purification of vegetable oils, including heating the oil, mixing with an aluminosilicate sorbent and filtering, characterized in that the natural mixture “kaolinite-β-quartz” is used as the sorbent in a ratio of 9: 1 ÷ 9.8: 0.2, pre-crushed with sodium percarbonate at a mass ratio of 8: 1 ÷ 12: 1 and treated with a solution of phosphoric acid with a concentration of 20-25%, taken in an amount of 50-75% by weight of the mixture, while the sorbent is introduced into the oil at a temperature of 65-75 ° C in an amount of 0.2-0.4%, and the mixing of the phases is carried out for 2 0-25 min with an intensity of 0.8-1.0 s ^-1 . 2. The method according to claim 1, characterized in that they use a natural mixture of the following grain composition, wt.%: 0.3 - 1.2 microns - 3-4; 1.2 - 2.5 microns - 8-9; 2.5 - 5 microns - 15-17; 5-10 microns - 23-25; 10 - 20 microns - 33-35; 20 - 40 microns - 13-15.