JP2009108266A - Method for producing fatty acid alkyl ester and/or glycerin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily produce high-quality fatty acid alkyl ester and/or glycerin in a high yield. <P>SOLUTION: An oil and an alcohol are reacted in the presence of a solid catalyst in a first reactor 10 and a second reactor 20 to obtain a reaction liquid containing fatty acid alkyl ester and/or glycerin. The alcohol is distilled from the reaction liquid using an alcohol distillation column 23 that is a distillation column provided with a heat exchanger having a short retention time, and the resulting reaction solution is phase-separated to a fatty acid alkyl ester phase and a glycerin phase. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a fatty acid alkyl ester and / or glycerin.

  As fatty acid alkyl esters, those obtained from animal and vegetable oils and fats are used as food, and are widely used in the fields of cosmetics and pharmaceuticals. Further, in recent years, attention has been focused on the use as a so-called biodiesel fuel in which a fatty acid alkyl ester is used directly as an alternative to light oil or added to light oil. Biodiesel fuel has various advantages such as low environmental burden compared to conventional petroleum diesel fuel.

  Glycerin is mainly used as a raw material for producing nitroglycerin, and is also used in a wide range of fields such as raw materials for alkyd resins, pharmaceuticals, foodstuffs, printing inks and cosmetics.

  As described above, fatty acid alkyl esters and glycerin are very useful. These can be produced by transesterifying triglycerides, which are the main components of fats and oils, with alcohols, as shown in the following reaction formula.

(In the above reaction formula, R represents an alkyl group having 6 to 22 carbon atoms or an alkenyl group having 6 to 22 carbon atoms having one or more unsaturated bonds)
Heretofore, the reaction shown in the above reaction formula has been generally performed using a homogeneous alkali catalyst.

  However, when a homogeneous alkaline catalyst is used, the catalyst separation and removal process becomes complicated. Moreover, the free fatty acid contained in fats and oils is saponified by an alkali catalyst, and soap is by-produced. Therefore, there is a problem that not only a washing process for washing with a large amount of water is required, but also the yield of the fatty acid alkyl ester is lowered due to the emulsifying action of the soap. Furthermore, the purification process for purifying glycerin is complicated.

Therefore, in order to solve the above problem, a method for producing a fatty acid alkyl ester and / or glycerin using a solid catalyst instead of a homogeneous alkali catalyst has been developed (for example, Patent Document 1). Compared with the method using a homogeneous alkali catalyst, the method using a solid catalyst not only can avoid the complexity of the treatment, but also can reduce waste such as waste water and waste salts generated in the reaction.
US Patent Application Publication No. 2004/0034244 (published February 19, 2004)

  However, in the conventional method for producing a fatty acid alkyl ester and / or glycerin using a solid catalyst, unreacted alcohols in the reaction solution are distilled off at any time using a general method involving evaporation and the like. It was. This is because the method using a solid catalyst uses an excessive amount of alcohol as compared with the method using a homogeneous alkali catalyst, and there is no step of removing the alcohol by water washing.

  Generally, fatty acid alkyl esters and / or glycerin obtained using animal and vegetable oils and fats as raw materials have a high boiling point. Therefore, when a small amount of alcohol remaining in the reaction solution is distilled off by an operation such as evaporation, it is necessary to heat it to a high temperature. At this time, the fatty acid alkyl ester and glycerides contained in the reaction solution, or the fatty acid alkyl ester and glycerin undergo a transesterification reaction, and a reverse reaction occurs in which fats and alcohols are generated. When the reverse reaction occurs, not only the yield of the fatty acid alkyl ester and / or glycerin is reduced, but also the glycerides as reaction intermediates are produced, so that the purity of the fatty acid alkyl ester of the final product is also lowered. In order to avoid high temperature, there is a method of evaporating under high vacuum, but the boiling point of the alcohol distilled off under high vacuum is low, so it is necessary to strengthen the cooling equipment to collect this. there were.

  Thus, the conventional method for producing a fatty acid alkyl ester and / or glycerin cannot easily produce a high-quality fatty acid alkyl ester and / or glycerin in a high yield. Therefore, a method for producing a fatty acid alkyl ester and / or glycerin that can be easily produced in high yield is desired.

  This invention is made | formed in view of the said subject, and aims at manufacturing a high quality fatty-acid alkylester and / or glycerol easily with a high yield.

  As a result of intensive studies by the present inventors, a distillation column equipped with a heat exchanger with a short residence time is used when distilling off unreacted alcohol from a reaction solution obtained by reacting oils and fats with alcohols. As a result, it was found that the yield and purity of the fatty acid alkyl ester as the final product were improved. Moreover, it discovered that the purity of the glycerol which is another final product improved by simultaneously performing alcohol distillation of the glycerol phase obtained at the said 1st phase-separation process in that case. Furthermore, it has been found that by sufficiently distilling off the alcohol before the second phase separation step, the distribution of the fatty acid alkyl ester to the glycerin phase is reduced and the yield of the fatty acid alkyl ester is improved.

  In order to solve the above problems, the method for producing a fatty acid alkyl ester and / or glycerin according to the present invention includes a first reaction step in which an oil and fat and alcohols are reacted in the presence of a solid catalyst, The first reaction liquid obtained in the reaction step is included in the first phase separation step of phase-separating the first fatty acid alkyl ester phase and the first glycerin phase into the first fatty acid alkyl ester phase. From the second reaction step in which fats and oils and alcohols are reacted in the presence of a solid catalyst, and from the second reaction liquid obtained in the second reaction step, the first reaction step and the second reaction step A purification step in which unreacted alcohol remaining without reacting in the reaction step is distilled off using a distillation column equipped with a heat exchanger having a short residence time; and the refined product obtained in the purification step. Things and is characterized in that it comprises a second phase separation step for phase separation and the second fatty acid alkyl ester phase and a second glycerin phase.

  According to said structure, in the 1st reaction process, fats and oils and alcohol are made to react in presence of a solid catalyst, Fatty acid alkyl ester, glycerin, unreacted said fats and oils, unreacted said alcohol And a first reaction liquid containing a reaction intermediate such as glyceride. Then, in the first phase separation step, the first reaction liquid is phase-separated to obtain a first fatty acid alkyl ester, the unreacted oils and fats, the unreacted alcohols, and the first reaction intermediate A fatty acid alkyl ester phase and a first glycerol phase containing glycerol and unreacted alcohols are obtained. Furthermore, in the second reaction step, the first fatty acid alkyl ester phase and the alcohol are reacted in the presence of a solid catalyst, whereby the second fatty acid alkyl ester, glycerin, and the second alcohol containing the unreacted alcohol are contained. A reaction solution is obtained.

  Subsequently, in the purification step, the unreacted alcohols are distilled off from the second reaction solution using a distillation tower equipped with a heat exchanger with a short residence time to obtain a purified product. Finally, the purified product is phase-separated in the second phase separation step to obtain a second fatty acid alkyl ester phase containing a fatty acid alkyl ester and a second glycerin phase containing glycerin.

  According to said structure, in the said 1st refinement | purification process, since alcohols are distilled off using the distillation tower provided with the heat exchanger with a short residence time, the fatty-acid alkylester which should become a final product, and / or It is possible to prevent the reverse reaction from proceeding by excessively heating glycerin, and to sufficiently remove the alcohols from the object to be phase-separated (the purified product) in the second phase separation step. As a result, it is possible to avoid the fatty acid alkyl ester from being distributed to the second glycerin phase to reduce the yield of the fatty acid alkyl ester, and to save the purification work after the phase separation.

  As mentioned above, according to said structure, a high quality fatty-acid alkylester and / or glycerol can be manufactured with a high yield and easily.

  The distillation tower equipped with the heat exchanger having a short residence time is composed of a scraped liquid film heat exchanger, a liquid film heat exchanger, a thin film rising heat exchanger, and a centrifugal thin film heat exchanger. A distillation column equipped with a heat exchanger selected from the group can be suitably used.

  The residence time is preferably 20 minutes or less. The said effect can be suitably show | played if the said residence time is 20 minutes or less.

  In the said 1st refinement | purification process of the manufacturing method of the said fatty-acid alkylester and / or glycerol, the unreacted which remained without reacting in a 1st reaction process from the said 1st glycerol phase further using the said distillation tower It is preferable to distill off alcohols.

  According to said structure, the distillation of alcohol from a 2nd reaction liquid and a 1st glycerol phase is possible by one distillation column. Here, as a distillation column for distilling off alcohols from the first glycerin phase, a distillation column in each stage of the above production method can be used. In the above configuration, in particular, from the second reaction solution. In the distillation column for distilling off alcohols, the alcohols are also distilled off from the first glycerin phase together with the second reaction liquid. As a method of distilling off alcohol from the first glycerin phase, for example, there is a method of evaporating alcohol before the first phase separation step. In order to reduce the alcohol concentration in glycerin to 1% or less, for example. Since it is necessary to heat the reaction liquid containing fatty acid alkyl ester and glycerin for a long time, the reverse reaction of the transesterification reaction occurs, which is not preferable. In addition, as in the production method described in Patent Document 1, a method in which the second reaction liquid distillation column is not used as the distillation column for distilling off alcohol from the first glycerin phase may be mentioned. An apparatus must be provided, which is not preferable.

  Furthermore, in said structure, alcohol is distilled off from the 1st glycerol phase using the said distillation tower. Therefore, in the case of obtaining the final product from the first glycerin phase in addition to the second reaction liquid, it is possible to avoid the reverse reaction from proceeding by excessive heating and the second phase separation step. Since the alcohols can be sufficiently removed from the object to be phase-separated in the above (purified product), the fatty acid alkyl ester is distributed to the second glycerin phase and the yield of the fatty acid alkyl ester is reduced. In addition, the time and effort of purification after the phase separation can be saved.

  In the method for producing the fatty acid alkyl ester and / or glycerin, unreacted alcohol remaining without reacting in the second reaction step is distilled from the second reaction solution before the first purification step. It is preferable to further include a second purification step to be left.

  According to said structure, before the said 1st refinement | purification process, the unreacted alcohol which remained without reacting in the said 2nd reaction process from the 2nd reaction liquid obtained in the said 2nd reaction process Therefore, the amount of alcohol contained in the object to be distilled off in the first purification step is reduced, and the unreacted alcohol can be distilled off more efficiently.

In the method for producing the fatty acid alkyl ester and / or glycerin, the reaction is performed in the first reaction step from the first reaction liquid obtained in the first reaction step before the first phase separation step. It is preferable to further include a third purification step for distilling off the remaining unreacted alcohol.
According to said structure, the quantity of alcohol contained in the target object which should be distilled off in a 1st refinement | purification process can reduce, and unreacted alcohol can be distilled off still more efficiently.

  In the purification step of the method for producing the fatty acid alkyl ester and / or glycerin, the distillation is preferably performed so that the unreacted alcohols contained in the obtained purified product are 0.5% by weight or less.

  According to said structure, since the said unreacted alcohol contained in the refinement | purification thing obtained in the said refinement | purification process is 0.5 weight% or less, fatty-acid alkylester distributes to a 2nd glycerol phase, and fatty-acid alkyl It is possible to avoid a reduction in the yield of the ester and to save the purification work after the phase separation. Therefore, according to said structure, high quality fatty-acid alkylester and / or glycerol can be manufactured with a high yield and easily.

  According to the present invention, in the method for producing a fatty acid alkyl ester and / or glycerin by reacting fats and oils in the presence of a solid catalyst, phase separation for obtaining the fatty acid alkyl ester and / or glycerin is performed. Before carrying out, since unreacted alcohols are distilled off from the object to be phase-separated using the distillation tower, high-quality fatty acid alkyl esters and / or glycerin can be easily produced in high yield. Can do.

  An embodiment of a method for producing a fatty acid alkyl ester and / or glycerin according to the present invention will be described. In the present specification, “fatty acid alkyl ester and / or glycerin” has the same meaning as “at least one of fatty acid alkyl ester and glycerin”.

  The method for producing a fatty acid alkyl ester and / or glycerin according to the present embodiment mainly includes a first reaction step, a second reaction step, a first phase separation step, a second phase separation step, and a first purification step. , A second purification step, a third purification step and a regeneration step. Details of these steps will be described below.

(Process for producing fatty acid alkyl ester and / or glycerin)
Here, the manufacturing process of the fatty acid alkyl ester and / or glycerin including each step described above will be described below with reference to FIG. FIG. 1 is a schematic view schematically showing an apparatus for producing a fatty acid alkyl ester and / or glycerin according to the present invention.

  As shown in FIG. 1, the manufacturing apparatus 1 which manufactures a fatty acid alkyl ester and / or glycerin mainly has an oil and fat storage tank 2, an alcohol storage tank 3, a waste storage tank 4, a fatty acid alkyl ester storage tank 5, and a glycerin. Storage tank 6, first reactor 10, first pressure flash tower 11, first atmospheric flash tower 12, alcohol purification tower 13, first separator 14, second reactor 20, second pressure flash tower 21 , A second atmospheric flash tower 22, an alcohol distillation tower 23, a second separator 24, a heat exchanger 30, a heat exchanger 31, and a line connecting them.

  As shown in FIG. 1, alcohol is supplied from the alcohol storage tank 3 to the first reactor 10, and fats and oils are supplied from the fat storage tank 2 to the first reactor 10. At this time, oils and fats and alcohols are heated and pressurized, and then supplied to the first reactor 10 filled with the solid catalyst. The first reactor 10 and the first reaction step in the first reactor 10 will be described in detail below.

  The first reaction liquid obtained in the first reactor 10 and containing reaction intermediates such as fatty acid alkyl ester, glycerin, unreacted oils and fats, unreacted alcohols, and glycerides is first pressurized. It is sent to the flash tower 11. The first pressurized flash tower 11 distills off unreacted alcohols from the first reaction solution, and the unreacted alcohols that have been distilled off are sent to the heat exchanger 30. The first reaction liquid from which unreacted alcohols have been distilled off is supplied to the first atmospheric flash tower 12. The first atmospheric flash tower 12 again distills off the unreacted alcohols contained in the first reaction solution, and the unreacted alcohols that have been distilled off are supplied to the alcohol purification tower 13. In the first atmospheric pressure flash tower 11, the reaction liquid from which unreacted alcohols have been distilled off is supplied to the first separator 14. Details of the third purification step in the first pressurized flash tower 11 and the first atmospheric flash tower 12 will be described in detail below.

  Subsequently, the heat exchanger 30 recovers the amount of heat of the unreacted alcohol that has been sent, and the unreacted alcohol whose amount of heat has been recovered is supplied into the alcohol purification tower 13. The alcohol purification tower 13 regenerates alcohols from the unreacted alcohols using the amount of heat recovered from the unreacted alcohols in the heat exchanger 30. The regenerated alcohol is sent to the alcohol storage tank 3 and used again as a raw material. Further, substances (wastes) other than alcohols contained in the unreacted alcohols are discharged out of the apparatus and stored in the waste storage tank 4. The heat exchanger 30 and the alcohol purification tower 13 and the regeneration step in the alcohol purification tower 13 will be described in detail below.

  On the other hand, the first separator 14 supplied with the first reaction liquid obtained by distilling off unreacted alcohols uses the supplied first reaction liquid as the first fatty acid alkyl ester phase (upper layer, hydrophobic phase). Phase separation into a first glycerin phase (lower layer, hydrophilic phase) (first phase separation step). The upper first fatty acid alkyl ester phase is mixed with the alcohol supplied from the alcohol storage tank 3 and supplied to the second reactor 20. Thereby, the unreacted fats and oils contained in the first fatty acid alkyl ester phase and the reaction intermediate are completely reacted with the alcohols. The second reactor 20 and the second reaction step in the second reactor 20 will be described in detail below.

  The second reaction liquid containing the fatty acid alkyl ester, glycerin, and the unreacted alcohol obtained in the second reactor 20 is sent to the second pressure flash tower 21. The second pressurized flash tower 21 distills off the unreacted alcohols from the second reaction solution, and the unreacted alcohols that have been distilled off are sent to the heat exchanger 31. Further, the second reaction liquid from which unreacted alcohols have been distilled off is supplied to the second atmospheric flash tower 22. The second atmospheric pressure flash tower 22 again distills off the unreacted alcohols contained in the second reaction liquid, and the unreacted alcohol thus distilled off is sent to the alcohol storage tank 3 as a raw material. Will be used again. In the second atmospheric pressure flash tower 22, the second reaction liquid from which unreacted alcohols have been distilled off is supplied to the alcohol distillation tower 23. Note that the first glycerin phase, which is the lower layer phase-separated in the first separator 14, is also supplied to the alcohol distillation column 23. Details of the second purification step in the second pressurized flash column 21 and the second atmospheric flash column 22 and details of the first purification step in the alcohol distillation column 23 will be described in detail below.

  Subsequently, the heat exchanger 31 recovers the amount of heat of the unreacted alcohol that has been sent, and the unreacted alcohol whose amount of heat has been recovered is sent to the alcohol storage tank 3. On the other hand, the alcohol reaction column 23 supplied with the second reaction liquid obtained by distilling off unreacted alcohols and the first glycerin phase separated in the first separator 14 is supplied with the second reaction liquid and the second reaction liquid supplied. Unreacted alcohols contained in one glycerin phase are further distilled off. The unreacted alcohols distilled off are supplied to the alcohol purification tower 13 and regenerated as alcohols.

  In the alcohol distillation column 23, a purified product obtained by distilling off unreacted alcohols from the second reaction liquid and the first glycerin phase is supplied to the second separator 24. The second separator 24 phase-separates the supplied purified product into a second fatty acid alkyl ester phase (upper layer, hydrophobic phase) and a second glycerin phase (lower layer, hydrophilic phase) (second phase). Phase separation step). Then, the second fatty acid alkyl ester phase that is the upper layer is sent to the fatty acid alkyl ester storage tank 5, and the second glycerin phase that is the lower layer is sent to the glycerin storage tank 6.

  The series of steps in the “reaction system” refers to the entire series of processing steps described above. That is, the processing steps other than the above-described processing steps are all “outside the reaction system”.

(Details of first reaction step and second reaction step)
Next, details of the first reaction step and the second reaction step will be described. Each of the first reaction step and the second reaction step is a step of producing a fatty acid alkyl ester and / or glycerin by mixing fats and oils and an alcohol and causing a transesterification reaction in the presence of a solid catalyst.

  In the transesterification reaction, fatty acid alkyl ester and glycerin can be obtained at the same time. Therefore, purified glycerin useful for various uses as a chemical raw material and fatty acid alkyl ester useful for biodiesel fuel are industrially simple. Can get to. Here, solid catalysts, alcohols and fats and oils that can be suitably used in the present invention will be described in detail below.

  The temperature of the mixed solution of fats and oils and alcohols in the first reactor 10 and the second reactor 20, that is, the reaction temperature is preferably in the range of 100 to 300 ° C, and in the range of 120 to 270 ° C. It is more preferable that it is in the range of 150 to 235 ° C. By setting the reaction temperature within the above range, the reaction rate can be sufficiently improved and the decomposition of alcohols can be sufficiently suppressed.

  The pressure in the first reactor 10 and the second reactor 20, that is, the reaction pressure is preferably in the range of 0.1 to 10 MPa, more preferably in the range of 0.2 to 9 MPa, and More preferably, it is in the range of 3-8 MPa. By setting the reaction pressure within the above range, the reaction rate can be sufficiently improved and side reactions can be sufficiently suppressed. When the reaction pressure exceeds 10 MPa, a special device that can withstand high pressure is required, and thus costs such as equipment costs are extra.

  The supply amount of alcohols and fats and oils supplied to the first reactor 10 and the second reactor 20 is within a range of 1 to 30 times the theoretical required amount of the supply amount of alcohols with respect to the supply amount of fats and oils. It is preferable to be within a range of 1.2 to 20 times, more preferably within a range of 1.5 to 15 times, and further preferably within a range of 2 to 10 times. Even more preferred. By making the supply amount of alcohols within the above range relative to the supply amount of fats and oils, the fats and alcohols can be sufficiently reacted, and the conversion rate of fats and oils can be sufficiently improved. In addition, since the amount of alcohol recovered in the third purification step or the second purification step and the utility cost for the alcohol purification tower 13 or the alcohol distillation tower 23 can be reduced, the manufacturing cost can be reduced. Can do.

  In addition, the theoretical required amount of alcohol in the present specification and the like refers to the number of moles of alcohol corresponding to the saponification value of fats and oils, and can be calculated by the following formula.

  Theoretical required amount of alcohol (g) = molecular weight of alcohol × [amount of used fat (g) × saponification value (mg (KOH) / g (fat)) / 56100].

  The form of the first reactor 10 and the second reactor 20 may be either a batch type or a fixed bed flow type, but is preferably a fixed bed flow type. By using the first reactor 10 and the second reactor 20 as a fixed bed reactor filled with a solid catalyst, the step of separating the catalyst can be eliminated. Thereby, since a complicated work process can be omitted, industrial production can be facilitated. Conventionally known conditions can be used for conditions such as reaction time when the first reactor 10 and the second reactor 20 are fixed bed reactors and when batch reactors are used.

  In addition, when fats and oils contain impurities, such as phospholipid and protein, you may provide the degumming reaction tank for adding the mineral acid and performing the degumming process which removes an impurity. The degumming reaction tank is preferably installed in front of the first reactor 10, and more preferably before mixing with fats and oils and alcohols.

(Details of the third purification step and the second purification step)
Next, details of the third purification step and the second purification step will be described. The third purification step and the second purification step are steps for distilling off unreacted alcohol from the reaction solutions obtained in the first reaction step and the second reaction step, respectively.

  The third purification step and the second purification step are preferably performed by at least two different pressures. Referring to FIG. 1, the first stage purification is the purification in the first pressure flash tower 11 or the second pressure flash tower 21, and the second stage purification is the first atmospheric flash tower 12 and the second pressure flash tower 21. Purification is performed in the atmospheric flash tower 22.

  The first stage purification in the third purification step and the second purification step, that is, the pressure in the first pressure flash tower 11 or the second pressure flash tower 21 is within the range of 0.15 to 1.5 MPa. It is preferable that it is within a range of 0.20 to 1.0 MPa. Moreover, it is preferable that the pressure in the 1st normal pressure flash tower 12 or the 2nd normal pressure flash tower 22 is a normal pressure. Note that “normal pressure” in this specification and the like means that the pressure is in the range of 0.095 to 0.105 MPa.

  If the pressure in the first purification in the third purification step and the second purification step is within the above range, the unreacted alcohols contained in the reaction solution can be sufficiently distilled off. Further, if the pressure in the first purification in the third purification step and the second purification step is within the above range, unreacted alcohols can be recovered at a temperature higher than the boiling point under normal pressure, Thereby, the heat of condensation of unreacted alcohols can be utilized in the regeneration process.

  In the present embodiment, the third purification process and the second purification process are two-stage purification, but the present invention is not limited to this and may be one stage, or may be three or more stages. Also good. However, it is preferable that the third purification step and the second purification step have two or more stages from the viewpoint that the calorific value of the unreacted alcohol can be effectively used as an energy source in the reaction system.

  As the first pressurized flash tower 11, the second pressurized flash tower 21, the first atmospheric flash tower 12, and the second atmospheric flash tower 22, a conventionally known flash tower can be used.

  Note that the third purification step and the second purification step are not necessarily performed. However, when the unreacted alcohol is not distilled off from the first and second reaction liquids, the fatty acid alkyl ester is distributed in the first or second glycerin phase in the subsequent first or second phase separation step, The final yield of fatty acid alkyl ester may be reduced.

(Details of the regeneration process)
Details of the reproduction process will be described. The regeneration step is a step performed in the alcohol purification tower 13 and is a step of purifying alcohols that can be used again as raw materials in the first or second reaction step from unreacted alcohols. In this specification and the like, “regeneration” means purification of unreacted alcohols as alcohols that can be used as raw materials in the reaction step.

  More specifically, the alcohol purification tower 13 used in the regeneration step is provided with heat exchangers 30 and 31 at the bottom (bottom) thereof, and the energy obtained in the heat exchangers 30 and 31 is not used. The alcohols are purified by distilling the reaction alcohols.

  Since the substance (waste) other than alcohol contained in the unreacted alcohol is mainly water, alcohol having a boiling point lower than that of water is generally obtained as alcohol gas from the upper part of the alcohol purification tower 13. The waste such as water having a boiling point higher than that of the alcohol is taken out from the lower part of the alcohol purification tower 13 and sent to the waste storage tank 4.

  In the case where the alcohol purified in the regeneration step is reused as a raw material, the water concentration contained in the alcohol is preferably in the range of 1000 ppm or less, more preferably in the range of 700 ppm or less, More preferably, it is in the range of 500 ppm or less. This is because when the alcohol contains moisture, the hydrolysis reaction of the fatty acid alkyl ester proceeds in the first or second reaction step, and the yield of the fatty acid alkyl ester decreases.

  The heat exchangers 30 and 31 are not particularly limited, but are preferably heat exchangers that use the amount of heat recovered from unreacted alcohols obtained in the third and second purification steps. That is, it is preferable to recover the heat at the time of condensing unreacted alcohols obtained in the third and second purification steps in the heat exchangers 30 and 31 and use it as an energy source in the alcohol purification tower 13.

  Further, the heat exchangers 30 and / or 31 may not use the recovered heat, or the heat exchanger may be either 30 or 31.

(Details of the first purification step)
The first purification step in the alcohol distillation column 23 includes a second reaction before phase separation of the second reaction liquid and the first glycerin phase to obtain a final product (fatty acid alkyl ester and / or glycerin). This is a step of removing alcohols from the liquid and the first glycerin phase.

  The alcohol distillation column 23 may be a distillation column provided with a heat exchanger (reboiler) having a short residence time, and specifically, a distillation column (for example, a thin film evaporator) provided with a scraped liquid film heat exchanger. And a distillation tower (for example, a falling film type concentrating device) equipped with a liquid film heat exchanger, a distillation tower equipped with a thin film rising heat exchanger, a distillation tower equipped with a centrifugal thin film heat exchanger, and the like.

  The residence time is preferably within 20 minutes, more preferably within 10 minutes.

  If the residence time is long, the reverse reaction of the transesterification reaction occurs depending on the temperature of the reboiler, the yield of the fatty acid alkyl ester is lowered, and accordingly the purity of the purified product is lowered.

  The reboiler temperature in the first purification step is preferably 250 ° C. or lower, more preferably 200 ° C. or lower. If the reboiler temperature exceeds 250 ° C., the reverse reaction of the transesterification occurs in a very short time, which is not preferable. For example, the time required for 0.1 mol% of the fatty acid alkyl ester to decompose by the reverse reaction is 35 minutes at 150 ° C., 10 minutes at 200 ° C., and 4 minutes at 250 ° C.

  The pressure in the first purification step is preferably within a range of 0.012 to 0.090 MPa, and more preferably within a range of 0.020 to 0.050 MPa. If the pressure is within the above range, it can be distilled at a temperature at which the reverse reaction of the transesterification reaction is unlikely to occur, and there is no need to reinforce the cooling device for collecting alcohol.

  In the first purification step, the alcohol distillation tower 23 having the above-described configuration is used, so that a small amount of alcohol can be sufficiently added to the second reaction solution and the first glycerin phase without much heat history. Can be distilled off. Therefore, it is possible to prevent the reverse reaction from proceeding by excessively heating the fatty acid alkyl ester and / or glycerin to be the final product contained in the second reaction liquid and the first glycerin phase. In addition, since the unreacted alcohol can be sufficiently removed before the second phase separation step, the fatty acid alkyl ester is distributed to the second glycerin phase in the second phase separation step, and the fatty acid alkyl A reduction in the yield of the ester can be avoided. Furthermore, since the amount of alcohols contained in the second fatty acid alkyl ester phase and the second glycerin phase obtained in the second phase separation step can be reduced, the purification after the second phase separation step Save time and effort.

  In the method for producing a fatty acid alkyl ester and / or glycerin according to this embodiment, as described above, unreacted alcohol is distilled off from the second reaction solution in the third purification step. The first glycerin phase is obtained by phase-separating the first reaction solution from which unreacted alcohols have been distilled off in advance in the second purification step. Therefore, the content of unreacted alcohol is already low in both the second reaction liquid and the first glycerin phase from which alcohols should be removed in the first purification step. Therefore, in the first purification step, a trace amount of alcohols contained in the second reaction solution and the first glycerin phase may be distilled off, and more preferably, the alcohol content of the purified product obtained is reduced. be able to.

  Specifically, in the first purification step, it is more preferable to perform purification so that the amount of alcohols contained in the obtained purified product is 0.5% by weight or less, and 0.3% by weight or less. It is more preferable to purify so that it may become 0.2 weight% or less.

  As described above, in the present embodiment, since the content of alcohol in the purified product is very small, as described above, the yield of the fatty acid alkyl ester is improved and after the second phase separation step. The time and effort of refining can be reduced.

  In the present embodiment, the first glycerin phase is distilled in the alcohol distillation column 23, but is not limited thereto. That is, you may distill in another distillation column. However, in that case, there is a possibility that alcohols cannot be sufficiently distilled from the first glycerin phase. In addition, if an already existing alcohol distillation column is not used, there is a risk of further costs. However, even in such a case, the present invention has the effects as described above because at least the second reaction solution is distilled using the distillation column.

(Additional notes)
A conventionally known separator can be used for the first separator 14 and the second separator 24, and the phase separation in the first separator 14 and the second separator 24 can be performed using a conventionally known method. it can. In the case of obtaining fatty acid alkyl ester and / or glycerin with higher purity in the first separator 14 and the second separator 24, a purification column is further provided after the first separator 14 and the second separator 24. It may be provided.

(Solid catalysts, alcohols and fats)
Here, solid catalysts, alcohols and fats and oils that can be suitably used in the present invention will be described.

(Solid catalyst)
The solid catalyst that can be suitably used in the present invention is a compound having a catalytic action in the transesterification reaction, being hardly dissolved in a reaction solution containing raw materials and products, and is a raw material such as fats and alcohols. And an insoluble solid catalyst that is insoluble in a reaction solution containing a fatty acid alkyl ester and glycerin as products. In the present specification and the like, “insoluble” of the solid catalyst means that the active component (for example, active metal component) is 1000 ppm or less, preferably 800 ppm or less, more preferably 600 ppm or less, more preferably in the reaction solution after the transesterification reaction. 300 ppm or less, most preferably means not detected by the analyzer. In addition, the density | concentration (elution amount) of the active component of the insoluble solid catalyst in a reaction liquid can be measured using a fluorescent X ray analysis method (XRF). In the fluorescent X-ray analysis method, the reaction solution after the reaction can be used in a solution state. Moreover, when measuring a very small amount of elution, it may be measured by a high frequency induction plasma (ICP) emission analysis method.

  As the solid catalyst that can be suitably used in the present invention, it is preferable that the solid catalyst can be easily removed from the reaction system after the transesterification reaction between fats and alcohols. The solid catalyst is an active catalyst for the esterification reaction of free fatty acids contained in fats and oils, that is, for both the ester exchange reaction of glycerides contained in fats and oils and the esterification reaction of free fatty acids. The catalyst is preferably active. Thereby, even if the fats and oils which are raw materials contain the free fatty acid, transesterification and esterification can be performed simultaneously. Thereby, the yield of fatty acid alkyl ester can be improved without performing an esterification reaction separately from the transesterification reaction.

  Specific examples of solid catalysts that can be suitably used in the present invention include alkali metal compounds, alkaline earth metal compounds, aluminum-containing compounds, silicon-containing compounds, titanium-containing compounds, vanadium-containing compounds, chromium-containing compounds, and manganese-containing compounds. Compound, iron containing compound, cobalt containing compound, nickel containing compound, copper containing compound, zinc containing compound, zirconium containing compound, niobium containing compound, molybdenum containing compound, tin containing compound, rare earth containing compound, tungsten containing compound, lead containing compound, A bismuth-containing compound or an ion exchange resin is preferred.

  Although it does not specifically limit as long as it has the said essential component as said compound, For example, it is preferable that it is a form, such as single, mixed or complex oxide, a sulfate, a phosphate, a cyanide, a halide, a complex. Among these, single, mixed, or complex oxides or cyanides are more preferable. Specifically, aluminum oxide, titanium oxide, manganese oxide, zinc oxide, zirconium oxide, and these or Mixtures and / or composite oxides with other metals, zinc cyanide, iron cyanide, cobalt cyanide, and mixtures and / or composite cyanides with these or other metals can be mentioned. These forms may be supported or immobilized on a support, and examples of the support include silica, alumina, silica / alumina, various zeolites, activated carbon, diatomaceous earth, zirconium oxide, and titanium oxide. , Tin oxide, lead oxide and the like.

  Examples of ion exchange resins include anion exchange resins. Specific examples of anion exchange resins include strong base anion resins and weak base anion resins. When anion exchange resins are classified according to the degree of crosslinking or porosity, they are gel type, porous type and high type. Examples thereof include a porous type.

(Oils and fats)
The fats and oils that can be suitably used in the present invention are those containing fatty acid esters of glycerin and can be used as starting materials for fatty acid alkyl esters and / or glycerin together with alcohols. It will not be specifically limited if it contains the fatty acid ester of glycerol called. Usually, it is preferable to use fats and oils containing triglyceride (triester of glycerin and higher fatty acid) as a main component and diglyceride, monoglyceride, free fatty acid and other minor components, but glycerin such as triolein or tripalmitin. The fatty acid ester may be used.

  Specific examples of such fats and oils include coconut oil, rapeseed oil, sesame oil, soybean oil, corn oil, sunflower oil, palm oil, palm kernel oil, coconut oil, safflower oil, linseed oil, cottonseed oil, tung oil and castor oil And vegetable oils such as beef fat, pig oil, fish oil and whale fat, and used oils (waste cooking oil) of various edible oils. In addition, these fats and oils may be used independently and may be used in mixture of 2 or more types.

  In addition, when the above-mentioned fats and oils contain impurities, such as phospholipid and protein, it is preferable to add mineral acids, such as a sulfuric acid, nitric acid, phosphoric acid, or boric acid, and to remove impurities. In the method for producing a fatty acid alkyl ester and / or glycerin according to the present invention, if a fatty acid alkyl ester and / or glycerin that is less susceptible to reaction inhibition by a mineral acid is used as a catalyst, Since it can manufacture efficiently, it is more preferable.

(Alcohols)
The alcohol that can be suitably used in the present invention is preferably an alcohol having 1 to 6 carbon atoms as the alcohol when producing biodiesel fuel, More preferably, alcohols are used. Examples of the alcohol having 1 to 6 carbon atoms include methanol, ethanol, propanol, isopropyl alcohol, 1-butanol, 2-butanol, t-butyl alcohol, 1-pentanol, 3-pentanol, 1-hexanol and 2 -Hexanol etc. can be mentioned. Among these, methanol or ethanol is preferable. Moreover, these alcohols may be used independently and may mix and use 2 or more types.

  In addition, when aiming at manufacture of the material used for edible oil, cosmetics, a medicine, etc., it is preferable to use a polyol as alcohol. Examples of the polyol include ethylene glycol, propylene glycol, glycerin, pentaerythritol and sorbitol. Among these, glycerin is preferable. Moreover, these alcohols may be used independently and may be used in mixture of 2 or more types.

  When a polyol is used as the alcohol, the method for producing a fatty acid alkyl ester in the present invention can be read as a method for producing glycerides, and can be suitably used in a method for obtaining glycerides. Moreover, in the manufacturing method of the fatty-acid alkylester and / or glycerol which concern on this invention, other trace components other than fats and oils, alcohols, and a solid catalyst may exist.

  In the present specification and the like, “alcohols” mean a generic name of compounds in which hydrocarbon hydrogen atoms are substituted with hydroxyl groups.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

[Example 1]
In this example, palm oil and methanol were used as reaction raw materials. Palm oil uses degummed palm oil obtained by precipitating proteins and phospholipids by adding phosphoric acid in advance, and has a free fatty acid content of 5.1% by weight and a moisture content of 0.06% by weight. It was used.

  The yields of fatty acid alkyl ester and glycerin were calculated as in the following formulas (1) and (2).

Yield of fatty acid alkyl ester = (number of moles of fatty acid alkyl ester in the upper layer (ester layer) extracted from the second separation device 24) / (number of moles of triglyceride at the inlet of the first reactor 10 × 3 + Number of moles of diglyceride x 2 + number of moles of monoglyceride) (1)
Yield of glycerin = (number of moles of glycerin in the lower layer (glycerin phase) extracted from the second separator 24) / (sum of moles of glycerides at the inlet of the first reactor 10) (2)
A MnTiO ₃ catalyst was used as the solid catalyst.

  The fatty acid alkyl ester and glycerin were produced using the production apparatus 1 as shown in FIG. Palm oil (2.5 kg / h) and methanol (2.5 kg / h) were mixed using a precision high-pressure metering pump and continuously passed downward from the upper part of the first reactor 10. The pressure in the reactor was 5 MPa, and the temperature was 200 ° C. Table 1 shows the material balance before and after the reaction.

  The reaction liquid obtained in the first reactor 10 was supplied to the first pressure flash tower 11. The pressure of the first pressure flash tower 11 was 0.35 MPa. The heavy liquid continuously withdrawn from the bottom of the first pressure flash tower contained 16.6% methanol. This was supplied to the first atmospheric flash tower 12. The heavy liquid withdrawn from the bottom of the first atmospheric flash tower 12 contained 9.7% methanol.

  The heavy liquid extracted from the bottom of the first atmospheric pressure flash tower 12 was supplied to the separator 14 and phase-separated. In the upper layer (fatty acid alkyl ester phase) extracted from the separator 14, fatty acid methyl ester is 87.1%, triglyceride is 2.4%, diglyceride is 1.1%, monoglyceride is 3.5%, and methanol is 5%. The lower layer (glycerin phase) contained 58.2% glycerin, 0.3% fatty acid methyl ester, 0.4% monoglyceride, and 41.1% methanol. The upper layer (fatty acid alkyl ester phase) extracted from the separator 14 (2.67 kg / h) and methanol (2.36 kg / h) are mixed and continuously downward from the top of the second reactor 20. Circulated. The pressure in the reactor was 5 MPa, and the temperature was 200 ° C. Table 1 shows the material balance before and after the reaction.

  The reaction solution obtained in the second reactor 20 was supplied to the second pressure flash tower 21. The pressure of the first pressurized flash tower 21 was 0.35 MPa. The heavy liquid continuously withdrawn from the bottom of the second pressure flash tower contained 14.4% methanol.

  The heavy liquid extracted from the bottom of the second atmospheric pressure flash tower 22 and the lower layer (glycerin phase) extracted from the separator 14 were mixed and supplied to the alcohol distillation tower 23. As the alcohol distillation column 23, a thin film evaporator was used. The pressure was 0.034 MPa, and the reboiler temperature was 175 ° C. The residence time of the liquid at this time was 2 minutes. The heavy liquid continuously extracted from the bottom of the alcohol distillation column 23 contained 0.07% methanol.

  The heavy liquid extracted from the bottom of the alcohol distillation column 23 was supplied to the separator 24 and phase-separated. In the upper layer (fatty acid alkyl ester phase) extracted from the separator 24, fatty acid methyl ester is 99.4%, triglyceride is 0.10%, diglyceride is 0.06%, monoglyceride is 0.41%, and methanol is 0. The lower layer (glycerin phase) contained 99.7% glycerol and 0.3% methanol.

  The yield of fatty acid alkyl ester was 99.5%, and the yield of glycerin was 98.9%.

[Comparative Example 1]
The same operation as in the example was performed except that methanol was distilled using a distillation tower equipped with a forced circulation heat exchanger as the alcohol distillation tower 23. In this case, the residence time of the alcohol distillation column 23 was 116 minutes. The reverse reaction occurred and the fatty acid methyl ester was degraded by 0.65%. Fatty acid methyl ester yield is 98.9%, purity is 98.6%, contains triglyceride 0.32%, diglyceride 0.18%, monoglyceride 0.80%, methanol 0.12% It was. The yield of glycerin was 98.1% and the purity was 99.2%.

[Comparative Example 2]
The liquid extracted from the bottom of the second atmospheric pressure flash tower 22 is supplied to the separator 24, and the upper layer (fatty acid alkyl ester phase) obtained by the separator 24 is distilled by the alcohol distillation device 23, thereby separating the separation device 14. And the operation similar to Example 1 was performed except having distilled the liquid mixture of the lower layer (glycerin phase) of the separation apparatus 24 with the new squall distillation column. In the second separator 24, 0.22% of the fatty acid methyl ester was distributed to the glycerin phase. The yield of fatty acid methyl ester was 99.3% and the purity was 99.4%. The glycerin yield was 98.9%, the purity was 97.7%, and the fatty acid methyl ester was 2.1%.

  INDUSTRIAL APPLICABILITY The present invention can be used to produce fatty acid alkyl esters and / or nitroglycerin raw materials that can be used as foods, cosmetics, pharmaceuticals, fuels, etc., alkyd resin raw materials, glycerin that can be used as pharmaceuticals, foods, paints, cosmetics, etc It is.

It is the schematic diagram which showed typically the manufacturing apparatus for enforcing the manufacturing method of the fatty-acid alkylester and / or glycerol which concern on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Production apparatus 2 Oil storage tank 3 Alcohol storage tank 4 Waste storage tank 5 Fatty acid alkyl ester storage tank 6 Glycerin storage tank 10 1st reactor 11 1st pressurization flash tower 12 1st atmospheric pressure flash tower 13 Alcohol purification Tower 14 First separator 20 Second reactor 21 Second pressurized flash tower 22 Second atmospheric flash tower 23 Alcohol distillation tower 24 Second separator 30, 31 Heat exchanger

Claims (7)

A first reaction step in which fats and alcohols are reacted in the presence of a solid catalyst;
A first phase separation step of phase-separating the first reaction liquid obtained in the first reaction step into a first fatty acid alkyl ester phase and a first glycerin phase;
A second reaction step of reacting the fats and oils contained in the first fatty acid alkyl ester phase with alcohols in the presence of a solid catalyst;
Unreacted alcohol remaining without reacting in the second reaction step from the second reaction solution obtained in the second reaction step is converted into a scraped liquid film heat exchanger, liquid film heat exchange. A first purification step of distilling off using a distillation column equipped with a heat exchanger selected from the group consisting of an evaporator, a thin film rising heat exchanger, and a centrifugal thin film heat exchanger;
A fatty acid alkyl ester comprising a second phase separation step of phase-separating the purified product obtained in the first purification step into a second fatty acid alkyl ester phase and a second glycerol phase. And / or a method for producing glycerin. A first reaction step in which fats and alcohols are reacted in the presence of a solid catalyst;
A first phase separation step of phase-separating the first reaction liquid obtained in the first reaction step into a first fatty acid alkyl ester phase and a first glycerin phase;
A second reaction step of reacting the fats and oils contained in the first fatty acid alkyl ester phase with alcohols in the presence of a solid catalyst;
From the second reaction liquid obtained in the second reaction step, unreacted alcohol remaining without reacting in the second reaction step is distilled with a heat exchanger having a residence time of 20 minutes or less. A first purification step for distilling off using a tower;
A fatty acid alkyl ester comprising a second phase separation step of phase-separating the purified product obtained in the first purification step into a second fatty acid alkyl ester phase and a second glycerol phase. And / or a method for producing glycerin.   In the first purification step, remaining unreacted alcohols are distilled off from the first glycerin phase without reacting in the first reaction step using the distillation column. Item 3. A method for producing a fatty acid alkyl ester and / or glycerin according to Item 1 or 2.   In the first purification step, the unreacted alcohol remaining without reacting in the second reaction step is distilled off from the second reaction liquid obtained in the second reaction step using the distillation column. The remaining unreacted alcohols are distilled off from the first glycerin phase without reacting in the first reaction step, and the fatty acid alkyl according to any one of claims 1 to 3 Method for producing ester and / or glycerin.   5. The method according to claim 1, further comprising a second purification step for distilling off unreacted alcohols from the second reaction solution before the first purification step. A method for producing a fatty acid alkyl ester and / or glycerin.   6. The method according to claim 1, further comprising a third purification step of distilling off unreacted alcohol remaining in the first reaction solution before the first phase separation step. The manufacturing method of the fatty-acid alkylester and / or glycerol of one term.   The said 1st refinement | purification process WHEREIN: The said distillation is performed so that the said unreacted alcohol contained in the refinement | purification obtained may be 0.5 weight% or less, Any one of Claims 1-6 The manufacturing method of the fatty-acid alkylester and / or glycerol of one term.

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