RU2261269C1 - Method for extracting of vegetable oils, apparatus for effectuating the same and submersible countercurrent extractor - Google Patents

Abstract

FIELD: fat-and-oil industry, in particular, production of vegetable oils by extraction method.

SUBSTANCE: method involves charging material to be extracted; extracting oil by solvent in submersible countercurrent extractor; drawing solvent vapors; condensing said vapors and returning to processing equipment; discharging oil cake and mycelium. Extraction process is carried out at phase "liquid-vapor" transition temperature under cavitation conditions. Apparatus has charging column with branch pipe for introducing of material to be extracted, branch pipes for introducing of used air with solvent vapors and for discharge of purified air, dosing screw, condenser, submersible countercurrent extractor with branch pipes for discharging of solvent vapors from extractor and for discharging of mycelium. Submersible countercurrent extractor is equipped with heating members for maintaining therein of phase "liquid-vapors" transition temperature and is made in the form of one or several sections. Decanter positioned in front of first section of countercurrent extractor comprises discharge pipe having widening lower part and adapted for creating of gas seal. Method and apparatus allow fat-free oil cake to be produced, which has high quality and is suitable for further reprocessing.

EFFECT: enhanced intensity of mass exchange at extraction stage, increased concentration and purity of mycelium produced, increased yield of extraction oil and improved quality thereof.

6 cl, 2 dwg

Description

The invention relates to the oil industry, in particular to the production of vegetable oils by extraction with organic solvents.

Currently known and widely used methods for producing vegetable oils by methods of cold or hot pressing. During hot pressing, it is possible to squeeze out the maximum amount of oil, however, it contains a large amount of related substances. Pressing seeds in cold presses results in lower oil yields, but they contain fewer related substances. However, all oils obtained by pressing methods contain a large amount of impurities and need to be cleaned.

Chemical extraction methods include extraction of vegetable oils with volatile organic solvents (usually low boiling gasoline fractions) followed by distillation of the extractant.

Known methods for extracting plant materials using organic solvents, in which the raw materials prepared for extraction are treated with solvent vapor, then the oil is preliminarily extracted in countercurrent with the solvent by repeatedly irrigating the extracted material with miscella and completing the extraction process in a vertical column irrigated with miscella. The distillation of the solvent from the extracted material is effected by exposure to superheated solvent vapors that do not exit the device, but, condensing on the meal, return to the extraction process (see RF patent No. 2166533, class C 11 V 1/10, 1999). The installation according to this patent contains a loading column with nozzles for introducing extractable material, a cleaned gas-air mixture and exhausting purified air, a reloading device with a miscella recirculation unit and a vertical extraction column with an auger and nozzles located inside for introducing extractable material, overheated solvent vapor and drainage. The vertical extraction column for the implementation of the extraction process is made countercurrent.

The main disadvantage of this method, the installation for its implementation and the extractor itself is the low mass transfer rate during the extraction process, which requires a sufficiently high ratio of solvent to extractable material and entails the production of low-concentration miscells.

A known method for the extraction of vegetable oils, including loading the extracted material, extracting the solvent with a solvent in a countercurrent extractor of a submersible type, selecting solvent vapors, condensing them and returning to the process, removing the meal and miscella. Before extraction begins, the extracted material is impregnated with saturated vapors of an organic solvent. Solvent oil extraction is carried out in a counterflow extractor type extractor and in a vertical counterflow extractor. In the extraction process, solvent vapor is selected, condensed and returned to the process, while the solvent is distilled off from the spent meal by exposing it to superheated solvent vapor and heating the meal in the discharge zone (see RF patent No. 2210589, class 11 B 1 / 10, 2001). The installation for implementing the known method comprises a loading column with a nozzle for introducing extractable material, nozzles for introducing exhaust air with solvent vapors and exhaust air, a screw metering device, a condenser, a counter-current extractor of a submersible type with nozzles for removing solvent vapor from the extractor to the condenser and returning condensed vapors, site for heating meal and solvent inlet nozzles and miscella discharge from the installation. The counterflow extractor of the submersible type for oil extraction included in the installation is installed horizontally.

These method, installation and extractor are closest to the proposed.

The main disadvantage of the known method, the installation for its implementation, and accordingly the extractor, as well as the previous ones, is the low intensity of mass transfer in the extraction process, due to the relatively low, 45-50 ° C, process temperature. In addition, the cooling of the extracted material provided in the installation by irrigation with its solvent leads to oilseed meal with increased oil content, and the use of a pump for recycling miscella complicates its operating conditions (since miscella contains a large number of particles of the extracted material with high abrasive properties) and leads to the presence of mechanical impurities in the discharged miscella.

An object of the present invention is to provide such a method for extracting vegetable oils, an apparatus for its implementation and a counterflow extractor of a submersible type included in the apparatus, which would increase the mass transfer rate at the extraction stage, increase the concentration and purity of the resulting miscella, providing an increase in the yield of extraction oil and improve its quality, as well as to obtain high-quality fat-free meal, suitable for further processing.

The problem is solved due to the fact that in the known method of extracting vegetable oils with organic solvents, including loading the extractable material, extracting the oil with a solvent in a countercurrent extractor of an immersion type, selecting solvent vapors, condensing them and returning to the process, removing the meal and miscella, the extraction process is carried out at the temperature of the liquid-vapor phase transition under cavitation conditions.

To solve the problem in a known installation for the extraction of vegetable oils with organic solvents, containing a loading column with a nozzle for inputting extractable material, nozzles for introducing exhaust air with solvent vapors and venting purified air, a metering screw, condenser, a counterflow submersible extractor with nozzles for venting solvent vapors from the extractor to the condenser and the return of condensed vapors, a unit for heating the meal and nozzles for introducing the solvent and removing the miscella, a submersible type flow extractor is equipped with heating elements to maintain the liquid-vapor phase transition temperature inside it and is made in the form of one or several sections, and a decanter is installed in front of the first submersible countercurrent type extractor, which has a downwardly extending loading pipe to create a gas shutter.

In this case, the sections of the counterflow extractor of the submersible type can be made horizontal, inclined, vertical, or a combination thereof. Optimal is the implementation of the installation for the extraction of vegetable oils, in which each section of the countercurrent extractor of the submersible type is installed with a slope in the direction of loading of the extracted material.

In another embodiment, the counterflow extractor of the submersible type, the first section in the direction of the extracted material is inclined, and the next horizontal.

To solve this problem, a counterflow countercurrent extractor for extracting vegetable oils with organic solvents contains a housing with nozzles for introducing extractable material, solvent and solvent vapor, miscella and meal, equipped with heating elements to maintain the temperature of the liquid-vapor phase transition inside it and is made in one or several sections.

The basis for the creation of the present invention was the numerous studies of the applicant, confirming the fact that the optimal temperature for the process of extraction of vegetable oils with organic solvents is a temperature equal to the boiling point of the solvent at a pressure corresponding to the pressure in the extractor; for example, for a solvent of the Nefras type, it is in the range of 68-72 ° C. At this temperature, oil extraction occurs under the conditions of a liquid-vapor phase transition, accompanied by cavitation processes due to boiling of the solvent and intensive mixing of the extractant in the layer of the extracted material. The hydrodynamics of the process is such that each particle of the layer of immiscible material is intensively and many times washed by the extractant. All this leads to a sharp increase in heat and mass transfer and, accordingly, intensification of the extraction process.

The proposed method is carried out, and the installation and countercurrent reactor operate as follows.

The material to be extracted enters the loading column, where it is impregnated with saturated solvent vapors that enter there together with the exhaust air, and by means of a metering screw it moves to the decanter, cleaning the miscellaneous impurities coming in countercurrent flow, after which it enters the counterflow submersible type extractor, the sections of which are equipped with heating elements. The extraction process is carried out at a temperature of the liquid-vapor phase transition under cavitation conditions. The solvent vapors formed in this process are removed from the extractor, condensed, and the condensate with a temperature close to the boiling point is returned to the extractor, thus providing solvent recirculation. This allows you to reduce the supply of fresh solvent to the device and, accordingly, increase the concentration of the finished miscella. The completeness of oil extraction is such that practically fat-free meal comes into the last section of the countercurrent extractor, where the solvent is distilled from it by supplying superheated solvent vapor and heating the meal itself.

The following is an example implementation of a method that is not limiting of the invention.

The extracted material in the form of a soybean lobe enters the charging column, where it is impregnated with saturated solvent vapors entering there together with the exhaust air, and by means of a metering screw it moves to the decanter, cleaning the miscellaneous impurities coming in countercurrent, and then it enters the counterflow submersible type extractor, six sections, inclined towards the loading of material, are equipped with heating elements made in the form of steam jackets, by means of which the temperature of and sections support within 68-72 ° C. The extraction process is carried out in a liquid-vapor phase transition and cavitation. The solvent vapors formed in this process are removed from the extractor sections, condensed and the condensate with a temperature close to the boiling point, and the extractor section is returned to the last section of the extracted material, thus ensuring solvent recirculation. The meal arriving in the last, seventh section of the countercurrent extractor for the final extraction and distillation of the solvent has an oil content of 0.7-1.0%. The extraction time is 21 minutes. The concentration of the finished miscella reaches the level of 50-70%.

The invention is illustrated by drawings, where figure 1 schematically shows a General view of the installation for the extraction of vegetable oils and included in its composition countercurrent extractor submersible type, and figure 2 is one of its options.

The plant for the extraction of vegetable oils contains a loading column 1 with a pipe 2 for introducing extractable material, a pipe 3 for introducing exhaust air with solvent vapors, a pipe 4 for extracting purified air, a metering screw 5 providing a constant level of extractable material in the loading column 1, decanter 6, which serves to pre-clean miscella from coarse suspensions and to maintain a constant level of extractant in a submersible type extractor.

Submersible countercurrent extractor is made in the form of several inclined sections 7, 8, 9, 10, 11, 12 connected to each other by means of reloading units 13, 14, 15, 16, 17. Each of the inclined sections 7, 8, 9, 10 , 11, 12 has internal screws 18 for moving the extracted material and heating elements made, for example, in the form of steam shirts 19. Each of the inclined sections 7, 8, 9, 10, 11, 12, is equipped with nozzles 20, 21, 22, 23, 24, 25 of the removal of solvent vapor generated during the extraction through droplet eliminators 26, 27, 28, 29, 30, 31 into the condenser 32, and nozzles 33, 34, 35, 36, 37, 38 for returning to the miscella section in case of foaming. The last section of the counterflow extractor is made in the form of an inclined column 39 with a screw inside (not shown in the drawing).

The inclined column 39 is equipped with a pipe 40 for removing solvent vapor from it to the condenser 41, a pipe 42 for returning condensate from the condensers 32 and 41, a pipe 43 for replenishing the extractor with a solvent from the reverse system. The inclined column 39 also has a pipe 44 for unloading the meal from the device, a meal heating unit 45 located in the upper part of the column and estrus 46 for emptying the inclined column 39 if necessary. The decanter 6 is equipped with a pipe 47 for discharging miscella from the device. The location of the nozzle 47 determines the height of the miscella in the inclined sections 7, 8, 9, 10, 11, 12, 39. Inside the decanter 6 there is a loading pipe 48 expanding downward, along which the extracted material coming from the metering screw 5 is lowered, and which serves to create a gas shutter that prevents the passage of saturated solvent vapors from the decanter 6 into the loading column 1. At the top of the decanter 6 there is a pipe 49 through which the gas space of the decanter 6 is connected to the gas space of the inclined tions (not shown). In the lower part of each inclined section 7, 8, 9, 10, 11, 12 there are nozzles 50, 51, 52, 53, 54, 55 for emptying the sections if necessary.

The installation option shown in figure 2 contains a loading column 56 with a pipe 57 for introducing extractable material, a pipe 58 for introducing exhaust air with solvent vapors, a pipe 59 for extracting purified air, a screw metering device 60, a decanter 61, an immersion type extractor having an inclined 62 and horizontal 63 sections with screws 64 and 65 located inside them, respectively, which are equipped with heating elements in the form of steam shirts 66 and 67, respectively. The submersible countercurrent extractor has another vertical section 68 for final oil extraction, inside of which there is a screw 69, and outside there is a heating element in the form of a steam jacket 70. The upper part of section 68 has a pipe 71 for unloading the meal and the heating unit for the meal 72, and the bottom - a pipe 73 for removing solvent vapor to a condenser 74 and a pipe 75 for returning condensed vapors, a pipe 76 for replenishing the solvent extractor and a pipe 77 for emptying the section 68. To empty the inclined section 62 and the decanter 61 a nozzle 78 is provided. Decanter 61 is provided with a nozzle 79 for discharging miscella from the device. Inside the decanter 61, a downwardly extending feed pipe 80 is located, through which the extractable material coming from the metering screw 60 is lowered, and which serves to create a gas shutter that prevents the passage of saturated solvent vapors from the decanter 61 into the charging column 56. In the upper part of the decanter 61 is placed a pipe 81 through which the gas space of the decanter is connected to the gas space of section 63 (not shown in the drawing).

Installation and, including counterflow extractor submersible type according to figure 1 work as follows. The prepared extractable material enters through the nozzle 2 into the loading column 1, from where it is fed by the metering screw 5 into the loading pipe 48 of the decanter 6, where, passing through the miscella layer, it is saturated with it and freed from air, which passes through the nozzle 49 into the gas space of the inclined sections. Saturated with miscella and freed from air, the material is lowered into the inclined section 7 and a screw (not shown) is moved to section 8 through the transfer unit 13. In the process of moving the material enters the zone of boiling miscella, saturating it with oil.

In the inclined sections 8, 9, 10, 11, 12 of a submersible countercurrent extractor, this process is repeated, while in each subsequent inclined section the strength of the miscella (oil content in the solvent) increases, and the oil content in the solid particles of the extracted material decreases, and the output of section 12 is already at the level of 1-1.5%.

In the inclined section 39, the material is washed with a clean solvent and the screw (not shown) is transported from the immersion zone into the solvent to the solvent evaporation zone. The solvent extracted from the extracted material is discharged through the pipe 44.

Solvent vapors resulting from the boiling of miscella in sections 7, 8, 9, 10, 11, 12, passing through droplet eliminators 26, 27, 28, 29, 30, 31 are cleaned of foam and droplets carried away in pairs, are condensed in a condenser 32, and the solvent vapor obtained by evaporating the solvent in section 39 is condensed in the condenser 41. The condensate of the solvent vapor through the nozzle 42 is discharged into the section 39 and moves towards the decanter through the inclined sections 12, 11, 10, 9, 8, 7 towards the flow of the extracted material .

Through pipe 43 to section 39, solvent is supplied to replenish the extractor from the circulating system in an amount corresponding to its content in the obtained miscell, which is removed from the extractor through pipe 47 of decanter 6. The vapor-air mixture from condensers 32 and 41 is transported by additional devices to loading column 1 through pipe 3 is cleaned of solvent vapor (due to absorption of the solvent by the oil contained in the extracted material) and is removed through the pipe 4.

Installation and counterflow extractor according to figure 2 work as follows. The prepared extractable material enters through the nozzle 57 into the charging column 56, from where it is fed by the feeder screw 60 into the loading pipe 80 of the decanter 61, where, passing through the miscella layer, it is saturated with it and freed from air, which passes through the nozzle 81 into the gas space of section 68. Saturated with miscella and freed from air, the material is lowered into the inclined section 62 and the screw 64 is moved into the horizontal section 63 of the counterflow extractor. In the process of moving the material enters the zone of boiling miscella, saturating it with oil.

In the vertical section 68 of the counterflow extractor, the material is washed with a clean solvent and conveyed from the immersion zone into the solvent to the solvent evaporation zone by a screw. The solvent extracted from the extracted material is discharged through the pipe 71.

Solvent vapors resulting from the boiling of miscella in sections 62, 63 of the counterflow extractor and section 68 are condensed in the condenser 74. The condensate of solvent vapors through the nozzle 75 is discharged into section 68 and moves toward the decanter through the horizontal 63 and inclined 62 sections of the counterflow extractor towards the flow extractable material.

Through pipe 76 to section 68, solvent is supplied to replenish the extractor from the circulating system in an amount corresponding to its content in the resulting miscell, which is removed from the extractor through pipe 79 of decanter 61.

The steam-air mixture from the condenser 74 is transported by additional devices to the loading column 56 through the nozzle 58, is cleaned of solvent vapor (absorption of the solvent by the oil contained in the extracted material) and is removed through the nozzle 59.

Studies conducted by the applicant have confirmed that the optimum temperature for the process of extraction of vegetable oils with organic solvents is the temperature equal to the boiling point of the solvent at a pressure corresponding to the pressure in the extractor. These studies showed that at this temperature, oil extraction occurs under the conditions of a liquid-vapor phase transition, accompanied by cavitation processes due to boiling of the solvent and intensive mixing of the extractant in the layer of the extracted material. The hydrodynamics of the process is such that each particle of the layer of immiscible material is intensively and many times washed by the extractant. All this leads to a sharp increase in heat and mass transfer and, accordingly, intensification of the extraction process. Thus, the present invention allows to increase the intensity of mass transfer at the extraction stage, to increase the concentration and purity of the resulting miscella, to provide an increase in the yield of extraction oil and improve its quality, as well as to obtain high-fat non-fat meal.

Claims (6)

1. A method of extracting vegetable oils with organic solvents, including loading the extractable material, extracting the oil with a solvent in a submersible countercurrent extractor, selecting solvent vapors, condensing them and returning to the process, extracting the meal and miscella, characterized in that the extraction process is carried out at a phase transition temperature "Liquid-vapor" in cavitation conditions. 2. Installation for the extraction of vegetable oils with organic solvents, containing a loading column with a nozzle for inputting extractable material, nozzles for introducing exhaust air with solvent vapors and exhaust air, a metering screw, a condenser, a counter-current submersible extractor with nozzles for removing solvent vapor from the extractor to the condenser and return of condensed vapors, a unit for heating the meal and nozzles for introducing the solvent and miscellaneous discharge, characterized in that the countercurrent extractor Submersible type provided with heating elements for maintaining inside the phase transition temperature "liquid-vapor" and is in the form of one or more sections, and before the first section of the counter flow extractor is installed decanter having a downwardly diverging loading tube to create a gas seal. 3. Installation according to claim 2, characterized in that the sections of the countercurrent extractor are installed with a slope in the direction of loading of the extracted material. 4. Installation according to claim 2, characterized in that the first section of the countercurrent extractor in the direction of movement of the material is inclined, and the next horizontal one. 5. Installation according to claims 3 and 4, characterized in that the meal heating unit is installed in the upper part of the last countercurrent extractor section in the direction of movement of the material. 6. The counterflow extractor of an immersion type for the extraction of vegetable oils with organic solvents according to the method of claim 1, characterized in that it comprises a housing with nozzles for introducing an extractable material, a solvent and removal of solvent vapors, miscella and meal, equipped with heating elements to maintain the phase temperature inside it transition "liquid-vapor" and is made in the form of one or more sections.

Images