RU2459863C1 - Method for vegetable oils purification using sunflower husk - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: filtering substance is represented by finely dispersed sunflower husk with particle size equal to 0.01-0.8 mm taken in an amount of 7.0-8.5 kg/t. Vegetable oil is mixed with sunflower husk at the winterisation stage, purification performed in the course of oil gradual cooling from 40°C to 8°C. Supplied for basic filtration is sunflower husk with particle size equal to 0.01-0.8 mm, the ratio of husk delivered into the crystalliser and into the exposer equal to 70%:30% of the total husk quantity. For preliminary inwash of the filtering stratum into oil husk with particle size equal to 0.3-0.8 mm is additionally introduced into oil in an amount of 1.0-1.5 kg/t.

EFFECT: oil quality improvement and filtration throughput capacity increase.

1 dwg, 1 tbl, 2 ex

Description

The invention relates to methods for refining vegetable oils and is intended for use in the oil and fat industry.

The process of refining sunflower oil includes a number of technological operations to remove related substances: phosphatides, waxes, free fatty acids, dyes, etc.

Voskopodobnye substances are practically not removed from the oil during normal refining, including hydration, alkaline neutralization, bleaching and deodorization. Therefore, the presence of wax-like substances in refined oil does not allow to obtain high-quality oils, moreover, it causes difficulties in the further processing of sunflower oils.

Voskopodobny substances reduce the activity of catalysts during hydrogenation, complicate the process of filtering oils and salomas. Wax crystals, due to the nature of their structure, are flattened by the difference in pressure and clog the pores of the filter elements, drastically reducing the speed of the process.

Given the above, the process of removing waxes and wax-like substances from sunflower oils becomes necessary not only to obtain a high-quality competitive product intended for direct consumption, but also to ensure normal technological conditions for the further processing of refined sunflower oils.

An effective way to remove wax-like substances from vegetable oil is winterization. Winterization consists in slowly cooling the oil and keeping it at a low positive temperature, followed by separation of the wax-containing precipitate from the purified vegetable oil by filtration. To optimize the filtration process, filter powders (FP) are used. Their use allows to ensure longer filter operation, improve throughput and obtain high filtrate transparency. The filter powder is applied directly to the filter membrane (cloth or mesh). This type of filtration is known as alluvial filtration.

At the enterprises, the operation of oil vinterization is the most costly. In this regard, the optimal choice of FP can improve the quality of refined oil, reduce the cost of oil and reduce oil loss with spent FP.

Currently, the following filter powders are best known:

- zeolites, perlites (for example, Nordisk Perlite, see "Oils and Fats", No. 5-6, pp. 14-17) - a natural rock of volcanic origin;

- kieselguhr - diatomaceous earth, diatomite (for example, Celatom trademark, EP Minerals company) - filter kieselguhr and perlite brand Celatom are produced from the highest quality ore from world deposits.

One of the main indicators of the quality of filter powder (FP) is its throughput (PS). PS characterizes the degree of dispersion of the phase transition and gives an approximate idea of its suitability for the type of filtering (thin, medium, rough). The particle size distribution of the phase transition is characterized by the percentage of particles divided into fractions of> 150 μm - 5%,> 100 μm - 17%,> 63 μm - 29%,> 45 μm - 40%,> 25 μm - 60%.

The use of inorganic materials (kieselguhr, perlite, etc.) allows the removal of particles up to 0.1 microns in size.

The disadvantage of mineral phase transitions (zeolites, kieselguhr, filter perlite, etc.) is that, having a highly developed surface, they contain internal pores and capillary channels, reaching, for example, more than 70% of the total particle volume for filter perlites. This leads to high losses of oil carried away by the internal pores and an increased consumption of filter powder, since not all of the surface of the particles has adsorption activity to waxes.

Inorganic FPs (kieselguhr, etc.) used in filtering vegetable oils as excipients, although they increase throughput and filtration quality, can give the oil a permanent aftertaste. It is impossible to use the sediment remaining after filtration for animal feed, and extracting oil from it is laborious and uneconomical, although the residual oil content of the sediment is 60–80.

A known method of cleaning oils from freezing waxes using filter powders (SU 1730129 A1, published. 04/30/92, IPC C11B 3/10 - ceased to function) [1], in which the spent filter powder is degreased in the extraction technology of extracting oil from oilcake by adding in unfiltered miscella, intensively mixed, then filtered, the separated precipitate is sent to the extractor and removed with meal.

The disadvantage of this method is the inability to reuse low-fat filter powder for freezing operations due to its contamination with meal (cake residues after oil extraction from it), as well as increased contamination of the extraction oil with wax obtained during subsequent distillation of miscella, which transfers it to the category of technical products.

A known method of purification of vegetable oils from waxes (RF patent 2261896, published. 10.10.2005. IPC С11В 3/00, С11В 3/16. Also published as European patent EP 1789522 (A1), WO 2006004454) [2].

The technical result of the invention is to increase the adsorption activity to the wax globules of the surface of the particles of the filter powder, to reduce its total consumption, to obtain concentrated wax grease products directly from spent sediments, to reduce losses of winterized oil by blocking the internal pores of the particles with a wax grease product. However, in the known method, as an AF, auxiliary filter kieselguhr powder under the trademark Celite-545 was used. The disadvantages of inorganic AF have been described above.

In the southern region of the Russian Federation, the utilization of sunflower husk is very urgent. With an increase in the production of main products - vegetable oil, the amount of waste during the processing of sunflower seeds increases: husk (husk), meal (non-fat residue).

Known filtering agent for oils and fats based on sunflower husk on.with. USSR 1025716 (Published: 06/30/1983 - expired. Author: Nikolay Petrovich Ihno) [3].

The essence of the invention is the use of sunflower husk with a particle size of 0.1-0.5 mm as a filter agent for oils and fats.

Being a solid plant material, sunflower husk can easily be crushed and divided into fractions. It does not impart a foreign taste to the oil, which improves the quality of the oil. The husk layer has less hydraulic resistance, and the oil filtration rate at 20 ° C increases by 3-4 times. Oil can be filtered through metal cloths or self-discharging high-performance filters can be used. According to the invention according to A.S. USSR №1025716 the amount of husk is 0.1-0.5% of oil. In order to avoid the transition from husk to wax and coloring matter oil, the process is conducted at a temperature not exceeding 70 ° C.

However, the particle size (particle size distribution of the FP) according to the invention [3] is insufficient for high-quality oil filtration. In addition, the specified temperature regime does not allow to accelerate the formation of stable, filtered crystals and their growth, which affects the speed and productivity of the oil refining process.

According to the totality of features, a known method of filtering vegetable oils by as USSR No. 1025716 [3] adopted as the closest analogue.

The technical result achieved by the claimed invention is to improve the quality of the oil, increasing the filtering capacity.

The technical result is achieved by the fact that the method of purification of vegetable oils at the technological stage of winterization, including mixing vegetable oil with a filter substance based on finely divided sunflower husk. According to the invention, a sunflower husk with a particle size of 0.01-0.8 mm is used, and cleaning is carried out by gradually cooling the oil from 40 to 8 ° C, and finely dispersed sunflower husk with oil is mixed in an amount of 7.0-8.5 kg / t in this case, for the main filtration, husk with a particle size of 0.01-0.8 mm is fed, with a ratio of 70% to the mold and 30% to the expositor of the total amount of husk supplied to the cooling section, and for pre-washing the filter layer into the oil is additionally introduced 1.0-1.5 kg / t husk with a particle size of 0.3-0.8 mm

Figure 1 shows the technological scheme of the process of winterization, explaining the inventive method, where:

Pos. 1 - 1st crystallizer; Pos. 2 - 2nd crystallizer; Pos. 3 - expositor; pos.4 - horizontal filter; pos.5 - hopper; Pos.6 - capacity for a mixture of oil with finely divided husk.

A method for purifying vegetable oils includes freezing vegetable oil with the addition of an auxiliary filter powder, keeping it at low temperature, applying the filter powder directly to the filter filter baffle, filtering the oil, separating the spent filter powder with a wax-containing precipitate from the purified vegetable oil.

Cleaning is carried out, with the gradual cooling of the oil from 40 to 8 ° C. The gradual cooling of the oil with the filtering powder accelerates the formation of stable wax crystals that are subjected to filtration and promotes their growth, which ensures the efficiency of the subsequent filtration process in sealed filters and the production of transparent oils.

Multiple experiments have shown that with a decrease in temperature and the use of a fine fraction of filter powder (finely dispersed sunflower husk), the growth of wax crystals increases. When using husk with a particle size of 0.01 ÷ 0.2 mm and with the gradual cooling of the suspension (oil with husk of sunflower), the growth of wax crystals increases. At a temperature of t ₁ = 40 ÷ 17 ° C, a particle size of 0.09 ÷ 0.3 mm, the growth of wax crystals is 1 ÷ 30%, at a temperature of t ₂ = 17 ÷ 10 ° C with particle sizes of 0.05 ÷ 0, 09 mm - crystal growth from 30 ÷ 50%, at a temperature t ₃ = 17-8 ° С; particle size 0.05 ÷ 0.01 mm - crystal growth from 50 ÷ 80%.

In comparison with the prototype, it can be seen that with particle sizes of 0.1 ÷ 0.5 mm at a temperature of 50 ÷ 60 ° C, the formation of wax crystals does not occur for reference, the melting temperature of waxes is 35 ° C).

The rate of wax formation depends on smooth cooling (according to the invention, t ₁ = 40-17 ° C, t ₂ = 17-10 ° C and t ₃ = 10-8 ° C) and aging in the mold.

A large fraction of particles F ₁ with a size of 0.3 ÷ 0.8 mm increases the rate of formation of an alluvial layer on the filter filter baffle, and for the main filtration, a fraction F ₂ with particle sizes of 0.01-0.8 is used, in which a small fraction with particle size 0.01-0.2 is an amplifier for the growth of wax crystals. This range of fractions allows you to get the maximum wax formation.

Finely dispersed husk is obtained by grinding on a grain mill with the appropriate dimensions of the mesh sieve or holes of perforated discs.

In the process of vinterization, hydrated, bleached oil enters the vinterization section and is supplied to the crystallizer 1 (Fig. 1).

Finely dispersed husk with a particle size of 0.01 ÷ 0.8 mm (item 7) is fed by a screw metering unit from hopper 5 into the cooling section in the amount of 7.0 ÷ 8.5 kg / t, where it is mixed with oil: it enters the crystallizer 1 70% and to the expositor 3 - 30% of the total number of husks fed to the cooling section. The oil and the finely dispersed husk come from above, flowing from the chamber to the chamber, and through the overflow enter the next crystallizer 2. Then the suspension from the oil with filter powder overflow enters the expositor 3, equipped with a slowly moving stirrer. The temperature conditions of the process t ₁ = 40 ÷ 17 ° C - in the mold 1; t ₂ = 17 ÷ 10 ° C - in mold 2 and t ₃ = 10 ÷ 8 ° C - in the expositor. From the expositor 3, a mixture of oil and filter powder is sent by a pump to a horizontal filter 4.

To prepare the filters for work - creating a filter layer on the dosing plates from the hopper 5, finely dispersed husk F ₁ 0.3 ÷ 0.8 mm in an amount of 1.0-1.5 kg / t is fed into the tank 6. The dosage of the supplied husk is determined experimentally . From the tank 6, a mixture of oil with finely dispersed husk F ₁ 0.3 ÷ 0.8 mm is fed to the horizontal filter 4 to obtain an alluvial layer. The process of forming an alluvial layer on the filters lasts 7 ÷ 10 min, the circulation continues until the creation of a working (alluvial) layer and obtaining a transparent oil.

The amount of sunflower husk 7-8.5 kg / t of oil provides a sufficient amount for the formation of crystallization centers for the effective removal of waxes and wax-like substances from the oil.

After filtration, the oil acquires a transparent golden color without an extraneous taste, the acid number decreases, as well as the moisture and phosphatides content. When heating the oil with husk, the transition to the oil of coloring substances and waxes does not occur.

Due to the claimed range of particle sizes, the husk is easily held in suspension and, with the gradual cooling of the oil from 40-8 ° C, accelerates the formation of stable waxes that are filtered, contributes to their growth and deep removal of wax substances.

Table 1 shows the performance of sunflower oil, refined using FP “Kieselguhr”, and using sunflower husk (according to the invention), in comparison with the reference, refined oil GOST52465-2005.

Table 1 Comparative physico-chemical characteristics of refined oil No. p / p Name Acid number, mg KOH Mass fraction of phosphorus-containing substances,% Moisture content, % Peroxide value, oxygen / kg Color one. Sunflower seed oil 2.14 0.597 0.1 4.7 fifteen 2. Ready oil after refining (use Kieselguhr) 0.19 0.009 0.001 0.28 3 3. Ready oil after refining (finely dispersed sunflower husk applied) 0.17 0.0079 0.02 0,095 3 four. Refined oil in accordance with GOST52465-2005 (premium, first grade) 0.30-0.40 Lack of 0.10 2-10 6-10

Examples of specific performance of the method.

Example 1. Finely dispersed husk with a particle size of 0.01 ÷ 0.8 mm (item 7) with a metering screw from hopper 5 is fed to the cooling section in an amount of 7.0 kg / t, where it is mixed with oil: into the crystallizer 1 - 70% and to the expositor 3 - 30% of the total. The oil and the finely dispersed husk come from above, flowing from the chamber to the chamber, and through the overflow enter the next crystallizer 2. Then the suspension from the oil with filter powder overflow enters the expositor 3, equipped with a slowly moving stirrer. Temperature conditions of the process t ₁ = 40 ° C - in the mold 1; t ₂ = 17 ÷ 10 ° C - in mold 2 and t ₃ = 10 ° C - in the expositor. From the expositor 3, a mixture of oil and filter powder is sent by a pump to a horizontal filter 4.

To prepare the filters for work - creating a filter layer on the dosing plates from the hopper 5, finely dispersed husk F ₁ 0.3 ÷ 0.8 mm in the amount of 1.0 kg / t is fed into the container 6.

From the tank 6, a mixture of oil with finely dispersed husk F ₁ 0.3 ÷ 0.8 mm is fed to the horizontal filter 4 to obtain an alluvial layer. The process of formation of the alluvial layer on the filters lasts 7 minutes, the circulation continues until the creation of the working (alluvial) layer and obtaining a transparent oil.

Example 2. The method is carried out analogously to example 1, while the parameters of the method are as follows: finely dispersed husk with a particle size of 0.01 ÷ 0.8 mm (item 7) with a metering screw from the hopper 5 is fed to the cooling section in an amount of 8.5 kg / t, where it is mixed with oil: 70% enters into the crystallizer 1 and 30% of the total amount enters the expositor 3. Temperature conditions of the process t ₁ = 17 ° C - in the mold 1; t ₂ = 10 ° C - in mold 2 and t ₃ = 8 ° C - in the expositor.

To prepare the filters for work - creating a filter layer on the plates - with a dispenser from hopper 5, finely dispersed husk F ₁ 0.3 ÷ 0.8 mm in the amount of 1.5 kg / t is fed into the tank 6. From the tank 6, the mixture is fed to the horizontal filter 4 oils with finely dispersed husk F ₁ 0.3 ÷ 0.8 mm to obtain an alluvial layer. The process of forming an alluvial layer on the filters lasts 10 minutes, circulation continues until a working (alluvial) layer is created and a transparent oil is obtained.

The oil after filtration according to examples 1 and 2 acquires a transparent golden color without an extraneous taste, the acid number decreases, as well as the moisture and phosphatides content. When heating the oil with husk, the transition to the oil of coloring substances and waxes does not occur.

The examples are not exhaustive, they only illustrate the possibility of using the invention.

The advantage of using finely dispersed sunflower husk in the claimed fraction size ratio at the technological stage of winterization in the method for refining oils is its low specific gravity, which allows it to remain in suspension (while mineral powders precipitate) and increase the rate of separation of the oil-wax mixture In addition, extracting oil from the cake in an oil press or centrifuge does not present a technical difficulty. Uncontaminated filtration waste can be completely disposed of as animal feed or composted.

In addition, finely dispersed sunflower husk reduces the wear of moving parts of equipment, in contrast to mineral filter powders, which are an abrasive.

The inventive method of purification of vegetable oils is effective and economical, due to the replacement of expensive mineral FP by filter powders from raw materials, which is a waste of agricultural production.

The advantage of using sunflower husk over wood pulp (wood waste) is that it does not contain additional impurities: sand, dust, etc., it does not need to be dried additionally, and it is more hydrophobic, because the composition includes lipids and residues of vegetable oil. In addition, sunflower husk does not contain soluble sugars (like sawdust).

Information sources

1. Auth. testimonial. USSR No. 1730129. A method of cleaning oils from waxes by freezing using filter powders (published. 30.04.92).

2. RF patent 2261896, published. 10/10/2005. Also published as European patent EP1789522 (A1), WO 2006004454.

3. Auth. testimonial. USSR 1025716. Filtering agent for oils and fats. Published: 06/30/1983. Author: Ikhn Nikolay Petrovich - the closest analogue.

Claims (1)

A method of purifying vegetable oils at the stage of winterization, comprising mixing vegetable oil with a filter substance based on finely dispersed sunflower husk, characterized in that a sunflower husk with a particle size of 0.01-0.8 mm is used, and cleaning is carried out with gradual cooling of the oil from 40 to 8 ° С, moreover, finely dispersed sunflower husk with oil is mixed in an amount of 7.0-8.5 kg / t, while for the main filtration, husk with a particle size of 0.01-0.8 mm is fed, with a ratio of 70%, to the mold and 30% - to the expositor from The total amount of husk supplied to the cooling section, and for preliminary washing of the filter layer into the oil, an additional 1.0-1.5 kg / t husk with a particle size of 0.3-0.8 mm is added.

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