LT4101B - Process for the rapeseed oil refining - Google Patents

Abstract

Invention belongs to the domain of edible oil, primarily rapeseed (colza) oil production and may be used to refine raw vegetable oil from admixtures, in order to comply with food oil standards.In order to reduce the number of treatment operations as well as power consumption, fresh oil is treated with dry soda, from 0.5 to 1.5 %, and with finely dispersed silica gel, from 1.0 to 2.5 % of the total mass of oil at ambient temperature, having precipitated the suspended particles and rinsing the sediments with water. The oil may be additionally treated with a water-based alkaline solution of non-soluble amides, from 0.3 to 0.5 % (decomposing into dry material) of the total oil mass. Further, the oil is deodorized by spraying it, along with 0.1 to 0.3 kg of low pressure superheated steam per kilogram of oil, into a vacuum sealed tank.

Description

The invention relates to the production of edible vegetable oils, in particular rapeseed oil, and can be used to purify crude vegetable oils from impurities to the requirements of edible oils.

Known methods for purifying crude oil do not exhibit a great variety of principles and, although differing in one parameter or another, consist of many of the same operations carried out on separate apparatus (see SU 1147739 A1, C 11 B 3/00, 1982; SU 1148861, 1983; SU 1687597). , 1989; RU 2034014 C 1, 6C 11 B 3/00, 1992; RU 2031920, 1992).

Although these techniques ensure sufficient oil quality, the large number of operations and equipment require high capital input and energy costs and complicate the production process.

A known method for cleaning cotton oil (see SU 1253993 A1, C 11 B 3/00, 1984) using silica gel to remove a specific component of this oil, gossypol, cannot be considered as an analogue.

The closest solution to the proposed solution (according to the oil quality result achieved) is the classical regulated method of oil purification (see ΒΗΜΜΧ, PyKOBOflCTBO no MeToąaM MccneflOBanun, τθχηοπογμηθοκομυ κοΗτροπκ) m yneTy nponsBOflCTBaM MacHnBMBBMBb - 1963) used in all oil-producing plants consisting of hydration of oil with hot water, separation of phospholipid residues (treatment with phosphoric acid) and vacuum drying, neutralization of free fatty acids with caustic soda, soap separation, oil washing with soap and vacuum, oil bleaching with bentonite (and other) moles, mole separation and deodorization, which is carried out by vacuum bubbling steam through the oil layer.

The oil cleaned in this way, like its analogues, requires large capital investments and a complicated production process, generates a large amount of difficult to recover waste, considerable oil loss during cleaning, high energy costs, including steam costs for deodorization. Therefore, this method cannot be used in small companies (less than 6 thousand tons of oil per year).

The object of the present invention is to reduce the number of crude oil refining operations and energy costs. This is possible by abandoning wet oil cleaning methods at higher temperatures and, at the same time, drying the oil, as well as reducing the cost of steam for oil cleaning and deodorizing.

The objective is achieved by treating freshly pressed oil with 0.5-1.5% dry baking soda and 1.0-2.5% by weight of fine dispersion dry silica gel at ambient temperature (without heating or freezing), precipitation of the suspended solids and washing of the precipitate with water. to reduce oil loss. The oil may additionally be purified with an aqueous solution of 0.3-0.5% (w / w) of the amide insoluble amides insoluble in alkali oil. In addition, the oil is deodorized by spraying it with low pressure superheated steam of 0.1-0.3 kg of steam per kg of oil into a vacuum container.

EXAMPLE:

Freshly pressed (with suspended particles) crude rapeseed oil is poured into a reactor with a stirrer. Depending on the amount of free fatty acids in the crude oil and the degree of removal desired, add 0.25-1.75% soda (Na ₂ CO ₃ ) by weight of the oil, stir at ambient temperature (25 ° C) and leave to settle. It is then spread in the upper part of the reactor

0.5-3.0% by weight of oil on a fine dispersion of dry silica gel and left to settle.

For the purpose of comparison, an oil purification analogous to that of the analogue was performed.

The same rapeseed oil is hydrated at 65 ° C by addition

1.5% by weight of the oil in hot water with vigorous stirring. Leave to stand for 2 hours. and separating the phospholipid precipitate, and the oil is exposed for 15 min. 85% phosphoric acid 1.0% by weight of the oil at 70-75 ° C. The oil is then dried in vacuo and neutralized at 60 ° C by the addition of a 140 g / l sodium hydroxide solution in a 20% excess of the stoichiometric amount and stirred for 30 min. Remaining 2 or. settle and separate the precipitate. The oil is washed with hot water until complete removal of the soap residue and vacuum dried.

The quality indices obtained for rapeseed oil, purification by suggested and analogous steps according to purification steps are given in Table 1.

table

Yesterday Production Oil Oil quality indicators No. stage feeling happy dys Humidity and volatile materials, % Acid- tinguistic mas, % Isothiocyanates, pers. j s. mg / kg Phospholipids, pers. i p, mg / kg Colors, mg J ₂ 1 Raw rapeseed 1 0.45 1.7 9.0 420 80 oil 2 0.7 2.6 12.5 580 85 2 Oil 1 0.3 0.40 6.5. 280 63 refined with 0.25% Na ₂ CO ₃ and 0.5% SiO ₂ 2 0.45 0.48 7.8 320 68

continuation of the table

Yesterday Production Oil Oil quality indicators No. stage feeling Humid- Acid- Isothiocyana- Phospholipid October happy and tinguistic this, read dai, read barely dys volatile mas, i s, j P. number, hunt, % mg / kg mg / kg mg % J ₂ 3 Oil 1 0.2 0.32 5.9 220 60 refined with 0.5% Na ₂ CO ₃ and 1.0% SiO ₂ 2 0.3 0.41 6.7 240 65 4 Oil 1 0.15 0.26 5.3 200 58 refined with 1.0% Na ₂ CO ₃ and 2.0% SiO ₂ 2 0.22 0.31 5.9 220 63 5 Oil 1 0.1 0.5 5.0 190 56 refined with 1.5% Na ₂ CO ₃ and 2.5% SiO ₂ 2 0.15 0.25 5.4 200 58 6th Oil 1 0.1 0.18 5.0 185 56 refined with 1.75% Na ₂ CO ₃ and 3.0% SiO ₂ 2 0.1 0.2 5.3 200 57 Analogs 7th After hydration 1 0.85 1.5 8.0 280 75 and sediment separation 1 0.9 2.7 10.0 390 78 8th After H ₃ PO ₄ and 1 0.3 1.8 7.0 270 62 vacuum drying 2 0.35 2.9 9.5 340 69 9th After neutralization- 1 0.2 0.3 6.0 190 55 flushing and vacuum drying 2 0.21 0.35 7.0 210 60

It can be seen from the table that rapeseed oil refined with 0.5-1.5% Na ₂ CO ₃ and 1.0-2.5% SiO ₂ fulfills the basic oil quality requirements achieved in multi-stage analogue refining. In addition, less soaps are formed, as alkaline fat hydrolysis with dry soda does not occur, which is inevitable in aqueous mixtures, so stoichiometric amounts of soda are sufficient for neutralization. However, the use of neutralized and dried oil for immediate use in the manufacture of foodstuffs shall not exceed 1 mg / kg of isothiocyanate. Therefore, the oil is further purified with amide solutions.

EXAMPLE:

Samples of freshly pressed crude rapeseed oil are poured into a reactor and mixed with e.g. the indicated amounts of soda (Table 1, # 3-5). The reactor is then charged with a 0.2-0.5% solution of alkali-urea-formaldehyde polycondensate (resin) in dry matter, so that the total moisture content of the mixture does not exceed 0.8%. Once the oil has settled, as described in Example 1, dry silica gel is applied. The quality characteristics of rapeseed oil purified by the proposed process are given in Table 2.

table

Yesterday Production Oil Oil quality indicators No. stage feeling happy dys Humidity and volatile materials, % Acid- tinguistic mas, % Isothiocyanates, conversion, mg / kg Phospholipids, pers. j p. mg / kg Colors sk mg J ₂ 1 Refined Oil 1 0.3 0.28 1.7 210 58 0.5% Na ₂ CO ₃ ; 0.2% KF polyconductor and 1.0% S1O2 2 0.4 0.35 2.2 240 62 2 Refined Oil 1 0.2 0.22 1.0 195 56 1.0% Na ₂ CO ₃ ; 0.3% KF polycond .and 0.2% SiO ₂ 2 0.26 0.27 1.3 210 60

continuation of the table

Yesterday Production Oil Oil quality indicators No. stage feeling happy dys Humidity and volatile materials, % Acid- tinguistic mas, % Isothiocyanates, pers. 5 S, mg / kg Phospholipids, pers. 5 P, mg / kg October barely number, mg Yeah? 3 Refined Oil 1 0.2 0.20 0.9 190 54 1.0% Na ₂ CO ₃ ; 0.4% KF polyconductor and 0.2% SiO ₂ 2 0.27 0.25 0.25 200 59 4 Refined Oil 1 0.18 0.14 0.8 175 51 that 1.5% Na ₂ CO ₃ ; 0.5% KF polyconductor and 2.5% SiO ₂ 2 0.21 0.20 1.0 190 55

From the table we can see that rapeseed oil, additionally refined with 0.3-0.5% (translated into dry matter) of urea-formaldehyde polycondensate, fulfills the quality requirement for food production - not more than 1 mg / kg of sulfur. Decreases acidity and so on. However, this can be improved by increasing the silica content. Other oil-insoluble amides may be used instead of urea-formaldehyde polycondensate.

EXAMPLE:

The samples of neutralized and dried rapeseed oil (Table 1, Nos. 4 and 9) were placed in reactors, heated to 100 ° C and added to 2% by weight of dry oil of bentonite clay (Polish Jeltar-Universal). Stir for 45 min. The oils are filtered off and sprayed with low pressure (0.7 kg / cm ² ) superheated (230 ° C) steam into a vacuum (-0.9 kg / cm ² ) reactor (proposed method) or deodorized by bubbling the same steam through an oil layer (analog) ). The deodorized oil quality data and steam consumption obtained are shown in Table 3.

table

Oil happy dys Steam content in kg / kg of oil Oil quality indicators General for cleaning Deso doravi- by the way Acid- rubber % Isothiocyanates, conversion S mg / kg Number of colors, mg J ₂ Peroxy dai, meq / kg p-Anisi- dino number 4.1 0.1 0.1 0.17 0.9 24th 3.8 3.2 4.2 0.1 0.1 0.19 1.0 28th 4.7 3.0 4.1 0.2 0.2 0.13 0.75 20th 3.1 2.8 4.2 0.2 0.2 0.14 0.9 25th 3.6 2.9 4.1 0.3 0.3 0.10 0.45 18th 2.5 2.4 4.2 0.3 0.3 0.11 0.6 21st 2.8 2.5 4.1 0.4 0.4 0.10 0.3 18th 2.4 2.2 4.2 0.4 Analogs 0.4 0.12 0.5 19th 2.8 2.3 9.1 0.7 0.4 0.18 0.8 25th 4.0 2.8 9.2 0.7 0.4 0.20 1.0 28th 5.1 3.0

It can be seen from the table that rapeseed oil deodorized by spraying into a vacuum reactor with low pressure superheated steam of 0.1-0.3 kg / kg oil achieves the quality requirements for edible oil. Analogically deodorized oil requires higher steam consumption for deodorization and more for general oil cleaning. In addition, cleaning oil in a known way consumes almost twice as much electricity.

The sludge formed by the treatment of the oil with baking soda and silica gel and filtration of the oil from the bleaching clay is collected in the reactor and washed with water slowly passing through the bottom of the reactor. At the top, the oil separates and decantes, collecting 8% of the total oil. This yields an oil purification yield of 95.5%, whereby only 93.1% yield is known.

The present invention has the following advantages over the prior art:

- reduce the number of technological operations and equipment;

- simplifies service and operation;

- reduces capital contributions;

- reduces steam and electricity costs;

- ensures high quality of oil;

- can be used to purify other vegetable oils.

Claims (3)

DEFINITION OF INVENTION 1, A method of purifying rapeseed oil by removing water, free fatty acids, isothiocyanates, phospholipids, and volatile oil odorous components from crude oil, characterized in that freshly squeezed oil is treated with 0.5-1.5% dry soda and dry fine silica gel 1 0-5.5% by weight of the oil at ambient temperature, precipitates the suspended solids and rinses the precipitate with water, then optionally cleans it with an aqueous solution of amides insoluble in alkaline oil, bleaches and deodorizes. 2, The method of purifying rapeseed oil according to claim 1, characterized in that the oil is additionally purified with an aqueous solution of an insoluble amide insoluble amides in an amount of 0.30.5% (w / w) of the oil. 3, A method of purifying rapeseed oil according to claims 1 and 2, characterized in that the oil is deodorized by spraying it with low pressure superheated steam to 0.10.3 kg of steam / kg of oil in a vacuum container.