KR102184632B1 - Method for preparing unsaturated fatty acid alkyl ester using palm fatty acid - Google Patents

Abstract

The present invention relates to a method for manufacturing unsaturated fatty acid alkyl ester using palm fatty acid. More specifically, the method simultaneously applies a multistage esterification and circulates alcohol used for the esterification in a plurality of reactors, in which the multistage esterification is generated, during an esterification step of reacting palm fatty acid with the alcohol to manufacture ester, such that reactivity between the palm fatty acid and the alcohol is increased, thereby increasing a yield rate of fatty acid alkyl ester. Moreover, saturated alkyl ester is centrifugally separated from the fatty acid alkyl ester, thereby manufacturing unsaturated fatty acid alkyl ester at a high selection ratio. The method comprises a first mixture acquisition step, a second mixture generation step, a centrifugal separation step, and an unsaturated fatty acid alkyl ester separation step.

Description

Manufacturing method of unsaturated fatty acid alkyl ester using palm oil fatty acid {METHOD FOR PREPARING UNSATURATED FATTY ACID ALKYL ESTER USING PALM FATTY ACID}

The present invention relates to a method for producing an unsaturated fatty acid alkyl ester using a palm oil fatty acid, and more specifically, in the esterification step of preparing a fatty acid ester by reacting an alcohol with a palm oil fatty acid, a multi-step esterification reaction is applied and the above By circulating the alcohol used in the esterification reaction in a plurality of reactors in which the multi-stage esterification reaction occurs, the reactivity of the palm oil fatty acid and the alcohol is increased to increase the yield of the fatty acid alkyl ester, and the saturated fatty acid alkyl ester is centrifuged from the fatty acid alkyl ester. It relates to a method for preparing an unsaturated fatty acid alkyl ester with high selectivity by separation.

Unsaturated fatty acid methyl esters are used as raw materials for various materials such as plasticizers, adhesives, coatings and surfactants through dimerization, epoxidation, polymerization or transesterification reactions thereof, and the fields in which these raw materials are used are also gradually increasing. There is a trend.

Conventionally, a fatty acid mixture containing saturated fatty acids and unsaturated fatty acids is prepared by hydrolysis under high temperature and high pressure conditions in the state of mixing oil and water, and then a solvent fractionation method, a surfactant fractionation method, a fractional distillation method, or a urea fraction fractionation method, etc. A method of preparing an unsaturated fatty acid methyl ester by separating an unsaturated fatty acid from the fatty acid mixture and reacting the unsaturated fatty acid with an acid catalyst and an alcohol is known.

In relation to this, a method for producing high-purity unsaturated fatty acids using animal and vegetable oil waste resources (Korean Patent Laid-Open Publication No. 10-2013-0107472, published on Oct. 02, 2013) is disclosed, and the prior art includes a urea addition crystallization method and a surfactant. It relates to a method of reducing energy costs and producing high-purity unsaturated fatty acids compared to other conventional separation and purification methods by sequentially performing the fractionation method.

Korean Patent Publication No. 10-2013-0107472 (2013. 10. 02)

The present invention is to prepare an unsaturated fatty acid alkyl ester comprising the step of separating and purifying an unsaturated fatty acid alkyl ester in a high yield by unifying the solvent fractionation method and the surfactant fractionation method, unlike the urea fraction fractionation method, in a simple manner compared to the urea fraction fractionation method. It aims to provide a method.

Further, the present invention is a method capable of improving the reactivity of palm oil-based fatty acids and alcohol in the step of preparing a fatty acid mixture to improve the yield of a fatty acid mixture containing unsaturated fatty acids, and further reducing the amount of alcohol used in the entire process. It aims to provide.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention that are not mentioned can be understood by the following description and will be more clearly understood by examples of the present invention. In addition, it will be easily understood that the objects and advantages of the present invention can be realized by means and combinations thereof indicated in the claims.

According to an aspect of the present invention for solving the above-described technical problem, (a) a agent comprising an unsaturated fatty acid alkyl ester and a saturated fatty acid alkyl ester through an esterification reaction of a reactant including a palm oil fatty acid, an acid catalyst, and an alcohol. 1 to obtain a mixture, wherein the esterification reaction is carried out continuously in at least two reactors connected in sequence, (b) a second mixture by mixing the first mixture obtained in step (a) with a surfactant and a solvent The step of generating a mixture, (c) centrifuging the second mixture produced in step (b) into a liquid phase and a solid phase, and (d) the unsaturation from the liquid phase separated in the step (c). There is provided a method for producing an unsaturated fatty acid alkyl ester using a palm oil-based fatty acid comprising the step of separating the fatty acid alkyl ester.

In one embodiment, the at least two reactors include a first reactor positioned relatively upstream and a second reactor positioned relatively downstream, and the alcohol is introduced into the second reactor in step (a). And can be circulated to the first reactor.

At this time, the circulation of the alcohol from the second reactor to the first reactor may be implemented by taking out a gaseous mixture containing alcohol evaporated from the second reactor and introducing it into the first reactor.

In addition, the gaseous mixture containing the evaporated alcohol from the first reactor can be taken out and put back into the first reactor. This improves the reactivity of the palm oil fatty acid and the alcohol during the entire process, as well as alcohol during the entire process. It is possible to reduce the amount of use.

In this case, the gaseous mixture may be mixed with at least a part of the reactant in the first reactor and introduced into the first reactor.

Additionally, in order to improve the reactivity of palm oil-based fatty acids and alcohols, the gaseous mixture taken out is condensed to remove at least a portion of water in the gaseous mixture, and then a gaseous mixture having a relatively increased alcohol content is added to the first reactor. I can.

In addition, the pressure in the first reactor is preferably maintained lower than the pressure in the second reactor. In this case, the pressure in the first reactor and the pressure in the second reactor may be kept constant regardless of the evaporation component generated in the second reactor and the introduction of the evaporation component into the first reactor.

According to the present invention, it is possible to improve the yield for a mixture of unsaturated fatty acid alkyl esters and saturated fatty acid alkyl esters by esterification reactions carried out sequentially and repeatedly in a plurality of reactors.

In particular, among the esterification reactants sequentially and repeatedly performed in the plurality of reactors, alcohol is introduced into a reactor located at a relatively downstream of the plurality of reactors and circulated to a reactor located at a relatively upstream of the esterification reactant. It is possible to improve the reactivity of heavy palm oil fatty acids and alcohols.

In addition, it is possible to reduce the amount of alcohol used in the esterification reaction of palm oil-based fatty acids by continuously refluxing the evaporated portion of the alcohol in the reactor.

In addition, after obtaining a fatty acid alkyl ester in a high yield through the above method, an unsaturated fatty acid alkyl ester can be obtained with a high selectivity through a unified fractionation process using a surfactant and a solvent, and energy in obtaining the unsaturated fatty acid alkyl ester It is possible to reduce costs and wastewater generation.

In addition to the above-described effects, specific effects of the present invention will be described together while describing specific details for carrying out the present invention.

1 schematically shows a step in which a multi-stage esterification reaction of palm oil-based fatty acids is performed in a method for preparing a fatty acid alkyl ester according to an embodiment of the present invention.
FIG. 2 schematically shows a step in which a multi-step esterification reaction of palm oil-based fatty acids is performed in a method for preparing a fatty acid alkyl ester according to another embodiment of the present invention.
FIG. 3 schematically shows a step of separating an unsaturated fatty acid alkyl ester therefrom after obtaining a fatty acid alkyl ester according to the method shown in FIG. 1 or 2.

Certain terms are defined herein for convenience in order to make the invention easier to understand. Unless otherwise defined herein, scientific and technical terms used in the present invention may have meanings generally understood by those of ordinary skill in the art.

In addition, unless otherwise specified in context, terms in the singular form also include their plural forms, and the terms in the plural form may also include their singular form.

Hereinafter, a method of preparing an unsaturated fatty acid alkyl ester according to various embodiments of the present invention will be described in detail with reference to the drawings referred to herein.

According to an aspect of the present invention, (a) a first mixture comprising an unsaturated fatty acid alkyl ester and a saturated fatty acid alkyl ester is obtained through an esterification reaction of a reactant comprising a palm oil fatty acid, an acid catalyst and an alcohol, and the ester The reaction is carried out continuously in at least two reactors connected in sequence, (b) mixing the first mixture obtained in step (a) with a surfactant and a solvent to produce a second mixture, (c ) Centrifuging the second mixture produced in step (b) into liquid and solid components, and (d) separating the unsaturated fatty acid alkyl ester from the liquid component separated in step (c). There is provided a method for producing an unsaturated fatty acid alkyl ester using a palm oil-based fatty acid containing.

The palm oil-based fatty acid used herein is a distilled fatty acid obtained by distilling a fatty acid (PFA; palm fatty acid) produced by mixing water with PAO (palm acid oil) generated in the palm oil refining process and hydrolyzing under high temperature and high pressure conditions. (PFAD; palm fatty acid distillate) and/or PMO (palm matter oil) generated as a by-product in the palm oil-based biodiesel process. The palm oil-based fatty acid used in step (a) may be used alone or in combination with the above-described various palm oil-based fatty acids.

As the acid catalyst used herein, a sulfuric acid catalyst may be used, and as the sulfuric acid catalyst, for example, sulfuric acid, toluene sulfonic acid monohydrate, methane sulfonic acid, etc. Can be used. In this case, the acid catalyst may be used in an amount of more than 0 to 0.5 parts by weight, preferably 0.1 to 0.3 parts by weight, based on 100 parts by weight of the palm oil-based fatty acid.

In addition, a base catalyst or a metal catalyst (tin or titanium catalyst) may be used instead of the acid catalyst described above, but the base catalyst has a disadvantage in that the esterification reaction rate is slow compared to the acid catalyst, and the metal catalyst requires a high reaction temperature. Accordingly, there is a problem that the yield of the fatty acid alkyl ester is lowered due to the generation of thermal polymerization by-products during the esterification reaction.

As the alcohol used herein, a monohydric alcohol having 1 to 10 carbon atoms, preferably a lower monohydric alcohol having 1 to 4 carbon atoms, may be used. The alcohol is mixed with the palm oil-based fatty acid and the acid catalyst and is not directly introduced into a reactor located upstream, but is introduced from a reactor located downstream, and the alcohol distillate taken out from the reactor located downstream is upstream. The alcohol injected into the reactor positioned at the downstream and as a whole may be circulated in a direction opposite to the flow direction of the reactant containing palm oil-based fatty acids during the entire esterification process.

Methanol initially introduced into the reactor located at the downstream is 0.05 to 0.5 parts by weight/minute, preferably 0.08 to 0.2 parts by weight/minute based on 100 parts by weight of palm oil fatty acids initially introduced into the reactor located at the upstream. Can be added continuously.

1-1 schematically shows a step (step (a)) in which a multi-step esterification reaction of palm oil-based fatty acids is performed in a method for producing an unsaturated fatty acid alkyl ester according to an embodiment of the present invention.

Referring to FIG. 1-1, a reactant including a raw fatty acid 1 including palm oil-based fatty acid and an acid catalyst 2 may be continuously introduced into the first reactor 4 along the flow path s1. . The reactant may flow to the second reactor 5 through the first reactor 4 and along the flow path s2, and the product after the reaction in the second reactor 5 passes through the flow path s12. Accordingly, it can be obtained as a first mixture (FAME) comprising an unsaturated fatty acid alkyl ester and a saturated fatty acid alkyl ester through sequentially neutralization, washing, dehydration and distillation processes.

The esterification reaction temperature in the first reactor 4 and the second reactor 5 may be 110°C to 180°C, preferably 120°C to 150°C, and the reaction pressure is 1.0 to 3.0 atm, preferably May be from 1.0 to 2.0 atm. In addition, the esterification reaction time in the first reactor 4 and the second reactor 5 may be 5 to 7 hours.

On the other hand, alcohol (3) as a reactant for the esterification reaction of the raw material fatty acid (1) is located relatively downstream of the first reactor (4) and the second reactor (5) along the flow path (s3). It is continuously introduced into the lower portion of the second reactor 5, and the alcohol introduced into the second reactor 5 may be circulated to the first reactor 4 in reverse to the flow direction of the reactant.

In the process of continuously introducing the alcohol into the second reactor 5, the pressure in the second reactor 5 is preferably kept constant within the range of 1.5 to 2.0 atm.

Some of the alcohol introduced into the second reactor 5 and/or a part of the reactant introduced into the second reactor 5 along the flow path s2 and the alcohol remaining after the esterification reaction may be evaporated. The gaseous mixture containing alcohol evaporated in the second reactor 5 is continuously re-introduced to the bottom of the first reactor 4 located upstream of the second reactor 5 along the flow path s4. Can be. Alcohol re-introduced into the first reactor 4 may participate in an esterification reaction with the reactant introduced into the first reactor 4 along the flow path s1.

At this time, in the process of continuously injecting the alcohol into the first reactor 4, the pressure in the first reactor 4 is kept constant within the range of 1.0 to 1.5 atm. At this time, the reverse of the alcohol For circulation, the pressure in the first reactor 4 is preferably lower than the pressure in the second reactor 5.

In a further embodiment, a cooler 5-1 may be located at the end of the flow path s4. The cooler 5-1 may remove at least a portion of water from the gaseous mixture by condensing the gaseous mixture after taking out a gaseous mixture containing alcohol evaporated in the second reactor 5. Accordingly, the water removed from the gaseous mixture is separated along the flow path s6, and the gaseous mixture with relatively increased alcohol content may be refluxed to the first reactor 4 along the flow path s5. have. By removing at least a portion of water in the gaseous mixture taken out from the second reactor 5, the alcohol content in the gaseous mixture may be relatively increased, and thus the gaseous mixture is transferred to the first reactor 4 When refluxing, the concentration of alcohol in the first reactor 4 is diluted, so that the esterification reaction efficiency is prevented from deteriorating. In addition, it is possible to keep the esterification process conditions in the first reactor 4 constant by making the concentration of alcohol in the gaseous mixture refluxed to the first reactor 4 constant.

Accordingly, the reactant introduced into the first reactor 4 along the flow path s1 and the alcohol introduced into the lower portion of the first reactor 4 along the flow path s5 may undergo an esterification reaction, Among the reactants, palm oil-based fatty acids may be converted into fatty acid alkyl esters. A fatty acid alkyl ester and an unreacted palm oil fatty acid, which are products of esterification reactions of palm oil fatty acids and alcohols, may move from the first reactor 4 to the second reactor 5 along the flow path s2. In addition, in other cases, by initially introducing an excess of palm oil-based fatty acid into the first reactor (4), the palm oil-based fatty acid is esterified with alcohol while moving from the first reactor (4) to the second reactor (5). You can make it react.

Meanwhile, some of the alcohol introduced into the first reactor 4 along the flow path s5 may not participate in the esterification reaction with the palm oil-based fatty acid and may evaporate. In this case, the gaseous mixture containing alcohol evaporated in the first reactor 4 may be re-introduced into the first reactor 4 along the flow path s7. The alcohol re-introduced into the first reactor 4 may re-engage in the esterification reaction with the reactant introduced into the first reactor 4. Accordingly, it is possible to improve the reactivity of palm oil-based fatty acids and alcohols among esterification reactions sequentially and repeatedly performed in the plurality of reactors through the re-reflux method of alcohol, and used for esterification of palm oil-based fatty acids. It is possible to reduce the amount of alcohol used.

In a further embodiment, a cooler 4-1 may be located at the end of the flow path s7. The cooler 4-1 may take out a gaseous mixture containing alcohol evaporated in the first reactor 4 and then condense the gaseous mixture to remove at least a portion of water from the gaseous mixture. Accordingly, the water removed from the gaseous mixture is separated along the flow path s9, and the gaseous mixture with relatively increased alcohol content is recirculated to the first reactor 4 along the flow path s8. I can. By removing at least a portion of water from the gaseous mixture taken out from the first reactor 4, the alcohol content in the gaseous mixture may be relatively increased, and thus the gaseous mixture is transferred to the first reactor 4 When refluxing, the concentration of alcohol in the first reactor 4 is diluted, so that the esterification reaction efficiency can be prevented from deteriorating. In addition, by making the concentration of alcohol in the gaseous mixture returned to the first reactor 4 constant, it is possible to maintain a constant process conditions for the esterification reaction in the first reactor 4.

In addition, an ejector 4-2 to which a circulation pump is connected may be located at an end of the flow path s8. The ejector (4-2) takes out at least a part of the reactants introduced into the first reactor (4) along the flow path (s10), and mixes the gaseous mixture that has passed through the cooler (4-1) to the Alcohol is absorbed in the reactant, and it can be re-introduced into the lower portion of the first reactor 4 according to the flow path s11. Through this process, the reactivity of the palm oil-based fatty acid and alcohol among the reactants may be further improved.

The esterification reaction continuously carried out in the first reactor 4 and the second reactor 5 is the total acid value of the product in the second reactor 5 according to the measurement of a total acid value (mg KOH/g). Can be terminated when it reaches 1.5 mg KOH/g or less. A first mixture (FAME) comprising an unsaturated fatty acid alkyl ester and a saturated fatty acid alkyl ester sequentially through neutralization, washing, dehydration and distillation processes along the flow path (s12) after the esterification reaction in the second reactor 5 is completed. Can be obtained as.

FIG. 2 schematically shows a step in which a multi-step esterification reaction of palm oil-based fatty acids is performed in a method for preparing an unsaturated fatty acid alkyl ester according to another embodiment of the present invention.

In the case of the multi-stage esterification reaction shown in FIG. 2, as compared to FIG. 1, an example in which one more reactor for performing the esterification reaction is added is shown, and the reactivity of palm oil-based fatty acids and alcohols as a reactor for performing the esterification reaction is added. By further improving the reaction yield can be increased.

Referring to FIG. 2, a reactant including a raw fatty acid 1 including palm oil-based fatty acid and an acid catalyst 2 may be continuously introduced into the first reactor 4 along the flow path s1. The reactant may flow to the second reactor 5 through the first reactor 4 and along the flow path s2, and then flow to the third reactor 6 through the flow path s3. The product obtained by completing the reaction in the third reactor 6 is a first mixture (FAME) comprising an unsaturated fatty acid alkyl ester and a saturated fatty acid alkyl ester through a neutralization, washing, dehydration and distillation process sequentially along the flow path s16. Can be obtained.

The esterification reaction temperature in the first reactor 4, the second reactor 5, and the third reactor 6 may be 110°C to 180°C, preferably 120°C to 150°C, and the reaction pressure is It may be 1.0 to 3.0 atm, preferably 1.0 to 2.0 atm. In addition, the esterification reaction time in the first reactor 4, the second reactor 5 and the second reactor 6 may be 5 to 7 hours.

On the other hand, alcohol (3) as a reactant for the esterification reaction of the raw material fatty acid (1) is continuously introduced into the lower portion of the third reactor (6) located at the most downstream along the flow path (s3), and the third The alcohol introduced into the reactor 6 may be circulated to the second reactor 5 and the first reactor 4 in reverse to the flow direction of the reactant.

In the process of continuously introducing the alcohol into the third reactor 6, the pressure in the third reactor 6 is preferably kept constant within the range of 1.7 to 2.0 atm.

Some of the alcohol introduced into the third reactor 6 and/or a part of the reactant introduced into the third reactor 6 along the flow path s3 and the alcohol remaining after the esterification reaction may be evaporated. The gaseous mixture containing alcohol evaporated in the third reactor 6 is continuously re-introduced to the lower portion of the second reactor 5 located upstream of the third reactor 6 along the flow path s5. Can be. The alcohol re-introduced into the second reactor 5 may participate in an esterification reaction with the reactant introduced into the second reactor 5 along the flow path s2.

At this time, in the process of continuously injecting the alcohol into the second reactor 5, the pressure in the second reactor 5 is kept constant within the range of 1.3 to 1.7 atm. At this time, the reverse of the alcohol For circulation, the pressure in the second reactor 5 is preferably lower than the pressure in the third reactor 6.

In a further embodiment, a cooler 6-1 may be located at the end of the flow path s5. The cooler 6-1 may remove at least a portion of water from the gaseous mixture by condensing the gaseous mixture after taking out a gaseous mixture containing alcohol evaporated in the third reactor 6. Accordingly, the water removed from the gaseous mixture is separated along the flow path s7, and the gaseous mixture with relatively increased alcohol content may be refluxed to the second reactor 5 along the flow path s6. have.

Meanwhile, some of the alcohol introduced into the second reactor 5 along the flow path s6 may not participate in the esterification reaction with palm oil-based fatty acids and may be evaporated, and evaporate in the second reactor 5 The gaseous mixture containing the alcohol may be continuously re-introduced into the lower portion of the first reactor 4 located upstream of the second reactor 5 along the flow path s8. The alcohol re-introduced into the first reactor 4 may participate in an esterification reaction with the reactant introduced into the first reactor 4 along the flow path s1.

At this time, in the process of continuously introducing the alcohol into the first reactor 4, the pressure in the first reactor 4 is kept constant within the range of 1.0 to 1.3 atm, and at this time, the reverse of the alcohol For circulation, the pressure in the first reactor 4 is preferably lower than the pressure in the second reactor 5.

Likewise, a cooler 5-1 may be located at an end of the flow path s8. The cooler 5-1 may remove at least a portion of water from the gaseous mixture by condensing the gaseous mixture after taking out a gaseous mixture containing alcohol evaporated in the second reactor 5. Accordingly, the water removed from the gaseous mixture is separated along the flow path s10, and the gaseous mixture with relatively increased alcohol content may be refluxed to the first reactor 4 along the flow path s9. have.

In addition, some of the alcohol introduced into the first reactor 4 along the flow path s9 may not participate in the esterification reaction with the palm oil-based fatty acid and may evaporate. In this case, the gaseous mixture containing alcohol evaporated in the first reactor 4 may be re-introduced into the first reactor 4 along the flow path s11. The alcohol re-introduced into the first reactor 4 may re-engage in the esterification reaction with the reactant introduced into the first reactor 4.

In a further embodiment, a cooler 4-1 may be located at the end of the flow path s11. The cooler 4-1 may take out a gaseous mixture containing alcohol evaporated in the first reactor 4 and then condense the gaseous mixture to remove at least a portion of water from the gaseous mixture. Accordingly, the water removed from the gaseous mixture is separated along the flow path s13, and the gaseous mixture with relatively increased alcohol content is recirculated to the first reactor 4 along the flow path s12. I can.

In addition, an ejector 4-2 to which a circulation pump is connected may be located at an end of the flow path s12. The ejector (4-2) takes out at least a part of the reactants introduced into the first reactor (4) along the flow path (s14), and mixes the gaseous mixture that has passed through the cooler (4-1) to the Alcohol in the reactant is absorbed, and it can be re-introduced into the lower portion of the first reactor 4 according to the flow path s15. Through this process, it is possible to further improve the reactivity of the palm oil-based fatty acid and alcohol among the reactants.

The esterification reaction continuously performed in the first reactor 4, the second reactor 5, and the third reactor 6 is determined according to the measurement of the total acid value (mg KOH/g). When the total acid value of the product in the reactor 6 reaches 1.5 mg KOH/g or less, it may be terminated. A first mixture (FAME) comprising an unsaturated fatty acid alkyl ester and a saturated fatty acid alkyl ester through sequential neutralization, washing, dehydration and distillation processes along the flow path 12 after the esterification reaction in the third reactor 6 is completed. Can be obtained as.

At this time, through the distillation process, the first mixture (FAME) may be recovered in an amount of 80 to 99 parts by weight, preferably 90 to 99 parts by weight based on 100 parts by weight of raw fatty acid.

FIG. 3 schematically shows a step of separating an unsaturated fatty acid alkyl ester therefrom after obtaining a fatty acid alkyl ester according to the method shown in FIG. 1 or 2. The steps shown in Fig. 3 include a series of steps (b) to (d) performed after step (a).

In step (b), a second mixture is produced by mixing the first mixture (1) obtained in step (a) with a surfactant (2) and a solvent (3).

Surfactant used herein is at least selected from sorbitan monostearate, sorbitan monolaurate, sorbitan monopalmitate and glycerin monostearate. One may be used, and is not particularly limited as long as it is a surfactant capable of stabilizing the unsaturated fatty acid alkyl ester from the first mixture (FAME) and improving the separation selectivity for the unsaturated fatty acid alkyl ester.

In addition, acetone and/or 95%-alcohol (a monohydric alcohol having 1 to 10 carbon atoms, preferably a lower monohydric alcohol having 1 to 4 carbon atoms) may be used as the solvent.

In the step (b), 0.001 parts by weight to 0.007 parts by weight of the surfactant and 0.15 parts by weight to 1 part by weight of the solvent per 1 part by weight of the first mixture may be mixed and then heated to 20°C to 30°C to dissolve.

Subsequently, the second mixture may be cooled to -7°C to -5°C at a rate of 3°C/hour to 5°C/hour to selectively precipitate a saturated fatty acid alkyl ester in the second mixture. The cooling of the second mixture may be performed by passing at least two cooling devices (4) to (7) sequentially arranged. Fine crystallization of the saturated fatty acid alkyl ester may be possible through such a sequential cooling method.

Next, in step (c), the second mixture in which the saturated fatty acid alkyl ester is precipitated in the form of fine particles is centrifuged (8) to separate the liquid phase (9) and the solid phase (10). As a result of the centrifugation, the liquid phase (supernatant) may contain an unsaturated fatty acid alkyl ester and a solvent, and the solid phase (lower liquid) may contain a saturated fatty acid alkyl ester, a surfactant, and a solvent. Of course, some surfactants and/or saturated fatty acid alkyl esters may be included in the liquid component 9, and conversely, some unsaturated fatty acid alkyl esters may be included in the solid component 10.

As described above, in step (b), a surfactant and a solvent are mixed with the first mixture (FAME) to produce the second mixture, and then the second mixture is centrifuged to obtain a liquid component containing an unsaturated fatty acid alkyl ester. It is possible to obtain selectively, and there is an advantage in that the unsaturated fatty acid alkyl ester can be separated from the liquid component without performing a conventional urea fractionation method through the separation process of step (d) to be described later.

In addition, in step (b), the surfactant fractionation method and the solvent fractionation method are unified to perform fractionation on the first mixture (FAME), and a plurality of fractionation methods are applied to separate unsaturated fatty acid alkyl esters. You can eliminate the hassle.

Finally, in step (d), the unsaturated fatty acid alkyl ester can be separated from the liquid component. In addition, it is possible to separate the saturated fatty acid alkyl ester from the solid phase.

In the step (d), after recovering the solvents (11-1) and (14-1) from the liquid component (9) or the solid component (10) using a solvent recovery device (11) and (14), washing water (12) and (15) are added, stirred and purified, and the unrecovered solvent and surfactant can be dissolved in the washing water and removed together with the washing water (12-1) and (15-1). The washed unsaturated fatty acid alkyl ester (UN-FAME) or saturated fatty acid alkyl ester (ST-FAME) can be finally removed from moisture in the dehydrators (13) and (16).

Hereinafter, specific embodiments of the present invention are presented. However, the examples described below are merely for illustrating or explaining the present invention in detail, and the present invention is not limited thereto.

Experimental method

Experimental Example 1

As shown in FIG. 2, a multi-stage esterification reactor was prepared in which a mixing tank, a first reactor, a second reactor, and a third reactor were sequentially connected. 2,100 g of palm oil-based fatty acids and 4.5 g of sulfuric acid were added to the mixing tank and the first reactor, respectively, and the temperature of the first reactor was maintained within the range of 130°C to 140°C.

The flow rate of the palm oil-based fatty acid and sulfuric acid transferred from the mixing ?j to the first reactor is 10.0 g/min, the flow rate of the reactant transferred from the first reactor to the second reactor is 10.6 g/min, and the second reactor In, the flow rate of the reactant transferred to the third reactor was 10.7 g/min, and the flow rate of the reactant discharged from the third reactor to the subsequent process was maintained at 10.7 g/min.

Meanwhile, methanol was continuously added to the lower portion of the third reactor at a rate of 2.4 g/min, and the internal pressure of the third reactor was maintained at 2.0 atm. After the methanol-containing gaseous mixture evaporated from the third reactor was continuously taken out, water in the gaseous mixture was partially condensed and removed in a cooler, and then was continuously introduced into the lower portion of the second reactor. The internal pressure was maintained at 1.5 atmospheres. Likewise, the methanol-containing gaseous mixture evaporated from the second reactor was continuously taken out and partially condensed and removed from the gaseous mixture in a cooler, and then was continuously introduced into the lower portion of the first reactor. At this time, the first reactor The internal pressure of was maintained at 1.0 atmosphere. The ejection rate of the methanol-containing gaseous mixture for each reactor, the composition for the ejection of the gaseous mixture for each reactor, and the composition for the ejection composition of the gaseous mixture by condensation of water by the cooler are shown in Table 1 below.

division Input speed (g/min) Reactor
Blowout composition (%) cooler
Blowout composition (%) 3rd reactor MeOH=2.4 MeOH=99.9% Water=0.1% MeOH=99.9%
Water=0.1% Second reactor MeOH/Water=2.4 MeOH=94.8% Water=5.2% MeOH=96.9%
Water=3.1% First reactor MeOH/Water=2.3 MeOH=59.1% Water=40.9% MeOH=78.4%
Water=21.6%

The multi-stage esterification reaction was terminated when the total acid value of the reaction product in the third reactor became 1.3 mg KOH/g.

Crude fatty acid methyl ester was obtained from the third reactor, cooled to 70° C., neutralized, washed and dehydrated, and then distilled to obtain purified palm oil-based fatty acid methyl ester (first mixture).

Subsequently, 2 g of sorbitan monostearate was added to 18 g of purified palm oil-based fatty acid methyl ester, followed by heating at 50°C. Here, 582 g of palm oil fatty acid methyl ester and 400 g of acetone were added and dissolved while stirring to obtain a second mixture. Next, the second mixture was slowly cooled from room temperature to -7°C to crystallize the saturated fatty acid methyl ester in the second mixture.

Next, the second mixture is centrifuged under conditions of -7°C/4,000 rpm to separate liquid and solid components, and the liquid component is introduced into a rotary evaporator for primary-normal pressure, 80°C/2nd-80torr, 80 Acetone was recovered under °C, and washed water corresponding to 20 wt% of the unsaturated fatty acid methyl ester was added, stirred and held to dissolve and separate unrecovered acetone and surfactant.

The washed unsaturated fatty acid methyl ester was put into a rotary vacuum evaporator and dehydrated at 10torr and 85°C. Saturated fatty acid methyl ester of the solid component was also purified and separated in the same manner as the unsaturated fatty acid methyl ester.

Experimental Example 2

Apart from the introduction of the methanol-containing gaseous mixture from the second reactor to the lower portion of the first reactor, the methanol-containing gaseous mixture evaporated from the first reactor is continuously taken out and partially condensed water in the gaseous mixture in a cooler. After removal, unsaturated fatty acid methyl ester and saturated fatty acid methyl ester were prepared in the same manner as in Example 1, except for mixing with some of the reactants of the first reactor through an ejector connected to a circulation pump and continuously injected into the lower portion of the first reactor. Was prepared.

The circulating amount of the reactant in the first reactor through the ejector was 50 g/min, and the flow rate of the gaseous mixture absorbed and circulated by the reactant circulated through the ejector was adjusted to be 5.6 g/min.

The ejection rate of the methanol-containing gaseous mixture for each reactor, the composition of the gaseous mixture taken out of each reactor, and the composition of the gaseous mixture obtained by condensation of water in each cooler are shown in Table 2 below.

division Input speed (g/min) Reactor
Blowout composition (%) cooler
Blowout composition (%) 3rd reactor MeOH=2.4 MeOH=99.9% Water=0.1% MeOH=99.9%
Water=0.1% Second reactor MeOH/Water=2.4 MeOH=94.8% Water=5.2% MeOH=96.9%
Water=3.1% First reactor MeOH/Water=2.3 MeOH=59.1% Water=40.9% MeOH=78.4%
Water=21.6% First reactor
(Ejector circulation) MeOH/Water=5.6 MeOH=59.1%
Water=40.9% MeOH=78.4%
Water=21.6%

Experimental Example 3

Unsaturated fatty acid methyl ester and saturated fatty acid methyl ester were prepared in the same manner as in Example 1, except that glycerin mono stearate was used instead of sorbitan monostearate as the surfactant.

Experimental Example 4

Unsaturated fatty acid methyl ester and saturated fatty acid methyl ester were prepared in the same manner as in Example 1, except that 95% ethanol was used instead of acetone as a solvent.

Experimental Example 5

Unsaturated fatty acid methyl ester and saturated fatty acid methyl ester were prepared in the same manner as in Example 1, except that a second mixture was obtained by mixing 600 g of palm oil fatty acid methyl ester and 400 g of acetone instead of adding 2 g of sorbitan monostearate.

Experimental Example 6

Unsaturated fatty acid methyl ester and saturated fatty acid methyl ester were prepared in the same manner as in Example 1, except that a second mixture was obtained by mixing 600 g of palm oil fatty acid methyl ester and 400 g of 95% ethanol instead of adding 2 g of sorbitan monostearate. I did.

Experimental Example 7

Saturated fatty acid methyl ester and saturated fatty acid methyl ester were prepared in the same manner as in Example 1, except that 1,000 g of methanol together with palm oil-based fatty acid and sulfuric acid were added to the first reactor without continuously adding methanol.

Experimental Example 8

Saturated fatty acid methyl ester and saturated fatty acid methyl as in Example 1, except that methanol was continuously added to the bottom of the first reactor at a rate of 2.4 g/min, but the alcohol evaporated in each reactor was not separately refluxed to the reactor. The ester was prepared.

Experimental Example 9

Saturated fatty acid methyl ester and a saturated fatty acid methyl ester in the same manner as in Example 1 except that water from the methanol-containing gaseous mixture was not removed from the third reactor and the second reactor, and was continuously introduced into the second reactor and the first reactor, respectively. Saturated fatty acid methyl esters were prepared.

In Experimental Examples 1 to 8, as the total acid value of 1.3 mg KOH/g was satisfied in the third reactor, the total amount (usage) of methanol added until the multi-stage esterification reaction was terminated, and the first mixture yield (multi-stage Conversion rate of palm oil-based fatty acid to fatty acid methyl ester by esterification reaction), the composition of the obtained unsaturated fatty acid methyl ester, and the final yield of the unsaturated fatty acid ester are shown in Tables 3 and 4 below.

division Experimental Example 1 Experimental Example 2 Experimental Example 3 Experimental Example 4 Methanol Amount (g) 420 402 419 423 First mixture yield (%) 93.7 95.6 94.2 93.9 fatty acid
Furtherance
(wt%) C14:0 ME 2.1 2.2 2.0 2.2 C16:0 ME 11.6 8.1 11.2 9.7 C18:0 ME 2.5 1.4 2.0 2.3 C16:1 ME 1.9 2.0 1.8 1.9 C18:1 ME 64.9 68.7 65.4 65.6 C18:2 ME 13.7 14.3 13.2 13.7 C18:3 ME 0.5 0.5 0.5 0.5 UN-FAME
yield(%) 49.9 52.1 50.1 48.5

division Experimental Example 5 Experimental Example 6 Experimental Example 7 Experimental Example 8 Experimental Example 9 Methanol Amount (g) 420 422 520 600 445 First mixture yield (%) 93.5 93.2 90.1 90.4 92.5 fatty acid
Furtherance
(wt%) C14:0 ME 1.8 1.9 2.0 2.0 2.0 C16:0 ME 26.1 22.6 15.0 15.4 15.4 C18:0 ME 5.3 4.9 2.6 2.8 2.8 C16:1 ME 1.4 1.5 1.8 1.8 1.8 C18:1 ME 52.0 54.9 61.9 62.0 62.0 C18:2 ME 10.5 11.2 12.5 12.6 12.6 C18:3 ME 0.3 0.4 0.5 0.4 0.4 UN-FAME
yield(%) 44.5 45.3 22.8 22.6 45.7

As described above, one embodiment of the present invention has been described, but those of ordinary skill in the relevant technical field add, change, delete or add components within the scope not departing from the spirit of the present invention described in the claims. Various modifications and changes can be made to the present invention by means of the like, and it will be said that this is also included within the scope of the present invention.

Claims (8)

(a) a first mixture comprising an unsaturated fatty acid alkyl ester and a saturated fatty acid alkyl ester is obtained through an esterification reaction of a reactant containing a palm oil fatty acid, an acid catalyst, and an alcohol, wherein the esterification reaction is performed at least two A step performed continuously in two reactors;
(b) mixing the first mixture obtained in step (a) with a surfactant and a solvent to produce a second mixture;
(c) centrifuging the second mixture produced in step (b) into a liquid phase and a solid phase; And
(d) separating the unsaturated fatty acid alkyl ester from the liquid component separated in step (c);
Including,
The surfactant is at least one selected from sorbitan monostearate, sorbitan monolaurate, sorbitan monopalmitate and glycerin monostearate,
Urea does not perform discrimination,
A method for producing an unsaturated fatty acid alkyl ester using a palm oil fatty acid.
The method of claim 1,
The at least two reactors include a first reactor positioned relatively upstream and a second reactor positioned relatively downstream,
In the step (a), the alcohol is introduced into the second reactor and circulated to the first reactor,
A method for producing an unsaturated fatty acid alkyl ester using a palm oil fatty acid.
The method of claim 2,
Taking out a gaseous mixture containing alcohol evaporated from the second reactor and introducing it into the first reactor,
A method for producing an unsaturated fatty acid alkyl ester using a palm oil fatty acid.
The method of claim 2,
Taking out a gaseous mixture containing alcohol evaporated from the first reactor and putting it back into the first reactor,
A method for producing an unsaturated fatty acid alkyl ester using a palm oil fatty acid.
The method according to claim 3 or 4,
Condensing the extracted gaseous mixture to remove at least a portion of water in the gaseous mixture, and then introducing a gaseous mixture having a relatively increased alcohol content into the first reactor,
A method for producing an unsaturated fatty acid alkyl ester using a palm oil fatty acid.
The method of claim 4,
The gaseous mixture is mixed with at least a portion of the reactant in the first reactor and introduced into the first reactor,
A method for producing an unsaturated fatty acid alkyl ester using a palm oil fatty acid.
The method of claim 3,
The pressure in the first reactor is maintained lower than the pressure in the second reactor,
A method for producing an unsaturated fatty acid alkyl ester using a palm oil fatty acid.
The method of claim 7,
The pressure in the first reactor is 1.0 to 1.5 atm,
The pressure in the second reactor is 1.5 to 2.0 atmospheres,
A method for producing an unsaturated fatty acid alkyl ester using a palm oil fatty acid.

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