JP4907872B2 - Method and apparatus for producing fatty acid ester - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method and apparatus for producing a fatty acid ester, and more particularly to a method and apparatus for producing a fatty acid ester for producing a fatty acid ester from a fatty acid raw material containing free fatty acid as a main component.

  In recent years, for example, a method for regenerating vegetable edible waste oil such as tempura oil into a light oil alternative fuel has been developed, and there are many devices therefor. Among them, there is a method for producing an alkyl ester of a fatty acid by subjecting a triglyceride contained in fats and oils to a transesterification reaction by reacting the fat and oil raw material with alcohol in an atmosphere in which the alcohol is in a supercritical state (Patent Document) 1 and 2).

  However, in the case of the method of Patent Document 1, the proportion of the fatty acid alkyl ester produced directly from the triglyceride is not necessarily high enough, and the use of various catalysts has been studied in order to improve the reaction rate. Is the actual situation.

In the case of the method of Patent Document 2, a method is described in which triglyceride is once hydrolyzed and converted into a fatty acid and then converted into a fatty acid alkyl ester. The efficiency of conversion to fatty acid alkyl ester is not necessarily high, and the conversion rate is low depending on the origin of the oil type and fat.
That is, there is a problem that it is difficult to satisfy the quality defined by the EU standard, which is one of the standards for fatty acid alkyl esters, only by the methods of Patent Document 1 and Patent Document 2.

JP 2001-31991 A International Publication No. 03/106604 Pamphlet

  The invention of the present application solves the above-mentioned problems, and does not use an alkali catalyst, and a method for producing a fatty acid ester capable of efficiently producing a fatty acid ester from a fatty acid raw material mainly composed of free fatty acids, and It is an object to provide a manufacturing apparatus. Furthermore, it aims at providing the manufacturing method and manufacturing apparatus of the fatty acid ester which can refine | purify the obtained fatty acid ester to the quality which can be used as a light oil alternative fuel.

In order to solve the above problems, the method for producing a fatty acid ester of the present invention ( Claim 1 ) comprises:
A fatty acid raw material containing free fatty acid as a main component and an alcohol are mixed, and the alcohol becomes a supercritical state. The esterification reaction is performed under the conditions of a temperature: 250 to 350 ° C. and a pressure: 15 to 25 MPa, and a fatty acid ester is obtained. A primary reaction step to be generated;
A cooling step of cooling the reaction solution reacted in the primary reaction step to a temperature of 100 ° C. or less, and a reaction solution cooled to a temperature of 100 ° C. or less in the cooling step, the alcohol becomes a supercritical state. A secondary reaction step in which the esterification reaction is performed again under the conditions of temperature: 250 to 350 ° C. and pressure: 15 to 25 MPa to generate a fatty acid ester.

The method for producing a fatty acid ester according to claim 2 is the method for producing a fatty acid ester according to claim 1 , wherein the fatty acid raw material is derived from at least one selected from the group consisting of vegetable oil, animal oil, vegetable oil or animal oil waste oil. It is characterized by that.

The method for producing a fatty acid ester according to claim 3 is the method for producing a fatty acid ester according to claim 1 or 2 , wherein the ratio of free fatty acid in the fatty acid raw material is 70% by weight or more. It is said.

The apparatus for producing a fatty acid ester of the present invention ( Claim 4 ) is:
A fatty acid raw material containing free fatty acid as a main component and an alcohol are mixed, and the alcohol becomes a supercritical state. The esterification reaction is performed under the conditions of a temperature: 250 to 350 ° C. and a pressure: 15 to 25 MPa, and a fatty acid ester is obtained. A primary reaction part to be generated;
A cooling section for cooling the reaction solution reacted in the primary reaction section to a temperature of 100 ° C. or lower;
The reaction liquid cooled to a temperature of 100 ° C. or lower in the cooling unit is subjected to esterification reaction again under the conditions of alcohol: supercritical state, temperature: 250-350 ° C., pressure: 15-25 MPa, and fatty acid. And a secondary reaction part for producing an ester.

The fatty acid ester production apparatus according to claim 5 is the fatty acid ester production apparatus according to claim 4 , wherein the primary reaction part, or the primary reaction part and the secondary reaction part are in a supercritical state. It is characterized by being a tubular reactor in which the esterification reaction is continuously performed by mutually dissolving and passing the fatty acid raw material or the mixed liquid of the reaction liquid after the primary reaction and the alcohol under the conditions as described above.

The apparatus for producing a fatty acid ester according to claim 6 further comprises an alcohol preheater for preheating the alcohol supplied to the tubular reactor to a temperature below its critical temperature in the apparatus for producing a fatty acid ester according to claim 5. It is characterized by having.

The fatty acid ester production apparatus according to claim 7 is the fatty acid ester production apparatus according to any one of claims 4 and 5 , wherein the fatty acid raw material preheater preheats the fatty acid raw material, and the alcohol has a temperature below a critical temperature. A preheated alcohol preheater, and a fatty acid raw material preheater and a mixing warmer that heats the fatty acid raw material and alcohol preheated in the alcohol preheater to a reaction temperature at which the alcohol becomes supercritical while mixing in a liquid phase state. It is characterized by having.

The fatty acid ester production apparatus according to claim 8 is the fatty acid ester production apparatus according to any one of claims 4 to 7 , wherein the reaction liquid after the reaction in the secondary reaction section is subjected to liquid-liquid separation. It is characterized by comprising a separating means for separating light liquid containing alcohol and glycerin as main components and heavy liquid containing fatty acid ester and high boiling point impurities.

The apparatus for producing a fatty acid ester according to claim 9 is the apparatus for producing a fatty acid ester according to claim 8 , wherein the separation means mechanically reacts the reaction liquid after the reaction in the secondary reaction section with the light liquid. It is a mechanical separation means for separating into the heavy liquid.

The fatty acid ester production apparatus according to claim 10 is the fatty acid ester production apparatus according to claim 8 or 9 , wherein the heavy liquid after the liquid-liquid separation is distilled and remains in the separation means without being completely separated. It is characterized by comprising a heavy liquid distillation means for separating a low-boiling component mainly composed of alcohol and water, a medium-boiling component mainly composed of a fatty acid ester, and a high-boiling component containing high-boiling impurities.

The fatty acid ester production apparatus according to claim 11 is the fatty acid ester production apparatus according to claim 10, wherein the fatty acid ester obtained by distilling the heavy liquid after liquid-liquid separation has a medium boiling point as a main component. It comprises a fatty acid removing means for separating and removing fatty acid contained in a small amount by a neutralization reaction with an alkaline aqueous solution, and an alkali removing means for washing and removing a small amount of remaining alkali.

The apparatus for producing a fatty acid ester according to claim 12 is the apparatus for producing a fatty acid ester according to claim 11 ,
It is characterized by comprising low boiling point component removing means for removing by distillation the low boiling point component mainly composed of water contained in the fatty acid ester after the fatty acid is removed by the fatty acid removing unit.

The fatty acid ester production apparatus according to claim 13 is the fatty acid ester production apparatus according to any one of claims 8 to 12 , wherein the light liquid after the liquid-liquid separation is distilled to alcohol, water, and glycerin. A light liquid distillation means for separation is provided.

Further, the fatty acid ester production apparatus according to claim 14 is the fatty acid ester production apparatus according to claim 13 , wherein the fatty acid ester production apparatus is separated by the alcohol recovery means for recovering the alcohol separated by the light liquid distillation means and the light liquid distillation means. It is characterized by comprising a glycerin recovery means for recovering glycerin.

The fatty acid ester production apparatus according to claim 15 is the fatty acid ester production apparatus according to any one of claims 5 to 14 , wherein a liquid space velocity in the tubular reactor is 0.3 to 0.03 [ 1 / min].

Moreover, the manufacturing apparatus of the fatty acid ester of Claim 16 is a manufacturing apparatus of the fatty acid ester in any one of Claims 7-15 ,
The temperature conditions and pressure conditions of the fatty acid raw material preheater and the mixing heater are as follows:
Temperature: 200-350 ° C
Pressure: 15-25MPa
It is characterized by being in the range of.

The fatty acid ester production apparatus according to claim 17 is the fatty acid ester production apparatus according to any one of claims 4 to 16 , wherein a lower alcohol having 1 to 5 carbon atoms is used as the alcohol. It is said.

The apparatus for producing a fatty acid ester according to claim 18 is used for producing a fatty acid ester used as a fuel in the apparatus for producing fatty acid ester according to any one of claims 4 to 17. It is said.

In the method for producing a fatty acid ester of the present invention (Claim 1), a fatty acid raw material mainly composed of a free fatty acid and an alcohol are mixed, and the alcohol becomes a supercritical state. Temperature: 250 to 350 ° C., pressure: 15 A primary reaction step in which an esterification reaction is performed under a condition of ˜25 MPa to produce a fatty acid ester, a cooling step in which the reaction solution reacted in the primary reaction step is cooled to a temperature of 100 ° C. or less, and a cooling step of 100 ° C. The reaction solution cooled to the following temperature is subjected to esterification reaction again under the conditions of temperature: 250 to 350 ° C. and pressure: 15 to 25 MPa, where the alcohol becomes a supercritical state. Because it is equipped with a reaction step, it is possible to efficiently produce fatty acid esters from fatty acid raw materials that contain free fatty acids as the main component, without using an alkali catalyst. It made.
In addition, when the reaction liquid in the primary reaction step is cooled to 100 ° C. or lower, and then the alcohol becomes a supercritical state again, and the secondary reaction is performed under the conditions of temperature: 250 to 350 ° C. and pressure: 15 to 25 MPa. The reason why the esterification reaction proceeds is not necessarily clear, but when the difference between the temperature rise start temperature of the secondary reaction and the reaction temperature becomes large, the contact state between the alcohol, which is the reaction solvent, and the raw oil / fat is increased during the temperature rise process. It is speculated that a dramatic change occurs and, as a result, the reaction is accelerated.

Fatty acid raw materials mainly composed of free fatty acids can be procured on the market, and can also be obtained by hydrolyzing fat raw materials mainly composed of fats and oils.
  In addition, as a method of hydrolyzing an oil-and-fat raw material and producing | generating a free fatty acid, it is possible to use the well-known various methods which are demonstrated below, for example.

  (1) A method in which an oil or fat is hydrolyzed by a batch or continuous stirring and mixing apparatus using an acid or alkaline chemical substance as a catalyst.
  (2) A method of hydrolyzing fats and oils using a batch or continuous stirring and mixing apparatus using an enzyme having a catalytic function with high reaction selectivity.
  (3) A method of efficiently performing hydrolysis by adding an emulsifier to an oil and fat and dispersing the oil and fat covered with an emulsifier film in an aqueous solution containing an enzyme as fine oil droplets.
  (4) A method of hydrolyzing fats and oils using a protein enzyme such as lipase.

  However, in the above primary reaction step, the esterification reaction does not necessarily proceed sufficiently, and the resulting fatty acid ester has insufficient quality, for example, the quality defined by the EU standard, which is one of the standards for fatty acid alkyl esters. It is difficult to satisfy
  However, after removing the low-boiling components including water and excess alcohol generated in the primary reaction step from the reaction solution reacted in the primary reaction step, alcohol is added to the reaction solution from which the low-boiling components have been removed, In the case where the esterification reaction is performed again under the supercritical condition, for example, a high-quality fatty acid ester that can be used as an alternative fuel can be efficiently produced.
  In the present invention, the temperature conditions of the primary reaction and the secondary reaction are in the range of 250 to 350 ° C., because when the temperature of the reaction part is less than 250 ° C., the esterification reaction without catalyst occurs sufficiently. It is necessary to perform reheating in order to obtain the temperature to be used, and it is not preferable. If the temperature of the reaction part exceeds 350 ° C., it becomes difficult to secure a heat source in the actual apparatus, and the equipment cost is significantly increased. It is not preferable, and it is not preferable because it causes thermal decomposition depending on the type of fatty acid.
  In addition, the pressure conditions for the primary reaction and the secondary reaction are in the range of 15 to 25 MPa because when the pressure is less than 15 MPa, the esterification reaction in the next step becomes insufficient, and when the pressure exceeds 25 MPa, the equipment cost is reduced. This is undesirable because it causes a significant increase.

Moreover, by using the method for producing a fatty acid ester of the present invention, a fatty acid can be efficiently obtained from a fatty acid raw material derived from at least one selected from the group consisting of vegetable oil, animal oil, vegetable oil or animal oil waste oil as in claim 2. Esters can be produced.
Examples of vegetable oils include rapeseed oil, soybean oil, palm oil, linseed oil, sunflower oil, sesame oil, and corn oil, and examples of animal oils include fish oil, cow oil, and pig oil.

Further, as in the method for producing a fatty acid ester according to claim 3 , by setting the ratio of the free fatty acid in the fatty acid raw material to 70% by weight or more, it can be used as an alternative fuel from a fatty acid raw material containing fatty acid as a main component. The fatty acid ester can be produced efficiently, which is particularly meaningful.

Moreover, the apparatus for producing a fatty acid ester according to the present invention ( Claim 4 ) mixes a fatty acid raw material mainly composed of a free fatty acid and an alcohol so that the alcohol becomes in a supercritical state. Temperature: 250 to 350 ° C., pressure In the primary reaction part which performs esterification reaction on the conditions of 15-25MPa, and produces | generates fatty acid ester, the cooling part which cools the reaction liquid made to react in a primary reaction part to the temperature of 100 degrees C or less, and a cooling part The reaction liquid cooled to a temperature of 100 ° C. or lower is subjected to an esterification reaction again under the conditions of temperature: 250 to 350 ° C. and pressure: 15 to 25 MPa so that the alcohol becomes a supercritical state, thereby generating a fatty acid ester. Since the secondary reaction part is provided, the manufacturing method of the fatty acid ester of Claim 1 of this application is implemented reliably, and fatty acid ester is obtained from the fatty acid raw material which has a free fatty acid as a main component. It becomes possible to manufacture efficiently.

The apparatus for producing a fatty acid ester according to claim 5 is the fatty acid raw material or the reaction solution and the alcohol after the primary reaction in the primary reaction section or the primary reaction section and the secondary reaction section under the condition that the alcohol is in a supercritical state. Because the tube-type reactor that continuously performs the esterification reaction by allowing the mixed fluid to pass through each other is passed, the fatty acid raw material or the reaction solution after the primary reaction and the alcohol are continuously and efficiently used. It becomes possible to dissolve and react with each other. Therefore, by using the fatty acid ester production apparatus according to claim 5 , it is possible to reliably carry out the fatty acid ester production method according to claims 1 to 3 of the present application and efficiently and economically produce the fatty acid ester. Become.

That is, when the mixed fluid of the fatty acid raw material or the reaction liquid after the primary reaction and alcohol (for example, methanol) is heated to a high temperature and a high pressure to be in a supercritical state (temperature of 240 ° C. or higher, pressure of 8 MPa or higher), the methanol is supercritical methanol. It becomes. This supercritical methanol is a highly electrically reactive fluid with high molecular density comparable to a liquid, while molecules move violently like a gas, and high-temperature solvolysis and methylation reactions proceed at high speed. It has features. Therefore, as in claim 5 , a tubular reactor is used, and a mixed fluid of a fatty acid raw material or a reaction liquid after the primary reaction and alcohol (for example, methanol) is placed in a supercritical region at a temperature and pressure in the tubular reactor. By passing through the inside, it becomes possible to react the fatty acid and the alcohol continuously and very efficiently, and it becomes possible to produce the fatty acid ester efficiently and economically.

The tubular reactor is a broad concept that means various types of tubular reactors such as a coil shape and a bellows shape, and there are no particular restrictions on the specific structure.
It is also possible to use various heat transfer promotion tubes configured to promote heat transfer inside and outside the tube by providing grooves, irregularities, protrusions, etc. on the inner peripheral surface of the heat transfer part of the reactor. Is possible.

  In addition, an inline mixer or the like is provided in the tubular reactor, and the solvent is brought into a supercritical fluid state in a state where the fatty acid raw material and the alcohol are sufficiently mixed. Can be efficiently dissolved together to further promote the esterification reaction.

Further, as in the fatty acid ester production apparatus according to claim 6, in the fatty acid ester production apparatus according to claim 5 , an alcohol preheater that preheats the alcohol supplied to the tubular reactor to a temperature below its critical temperature. By adopting such a configuration, it is possible to efficiently preheat the alcohol that forms the main part of the fluid supplied to the tubular reactor, and to reduce the size of the tubular reactor. In addition, the alcohol is preheated to a temperature below the critical temperature because the alcohol can be kept in a liquid phase by preheating to a temperature below the critical temperature, and the fatty acid raw material is also in the liquid phase. This makes it possible to improve the mixing and dispersion of the resin and promote the mutual dissolution and the esterification reaction in the subsequent temperature raising process.

Moreover, in the fatty acid ester production apparatus according to claim 7, in a fatty acid raw material preheater for preheating a fatty acid raw material, an alcohol preheater for preheating alcohol to a temperature below a critical temperature, a fatty acid raw material preheater, and an alcohol preheater The preheated fatty acid raw material and alcohol are mixed in a liquid phase state, and the mixture is heated to a reaction temperature at which the alcohol becomes a supercritical state. It is possible to efficiently preheat the entire fluid and reduce the size of the tubular reactor.
That is, as in the apparatus for producing a fatty acid ester according to claim 7, after the fatty acid raw material and the alcohol are preheated individually by the fatty acid raw material preheater and the alcohol preheater, the mixture is mixed in the liquid phase state in the mixing temperature rising device. By raising the temperature to the reaction temperature at which the alcohol is in a supercritical state, the fatty acid raw material preheater promotes the decomposition of some of the triglycerides contained in the fatty acid raw material into free fatty acids. By mixing the fatty acid raw material and the liquid phase alcohol preheated to a temperature below the critical temperature, the mutual dissolution and the esterification reaction are promoted in the subsequent temperature rising process, and sufficient reaction efficiency is achieved. Thus, it is possible to reduce the size of the tubular reactor.
In addition, as a mixing temperature rising device for mixing a fatty-acid raw material and alcohol in a liquid phase state, the structure using the tube-type mixing temperature rising device provided with the in-line mixer etc. are illustrated, for example.

Further, as in the fatty acid ester production apparatus according to claim 8 , the reaction liquid after the reaction in the secondary reaction part is subjected to liquid-liquid separation, a light liquid mainly comprising alcohol and glycerin, fatty acid ester and high By adopting a configuration including a separation means for separating the heavy liquid containing boiling point impurities, the light liquid and the heavy liquid can be separated to efficiently produce the fatty acid ester.

Further, as in the fatty acid ester production apparatus according to claim 9 , mechanical separation means for mechanically separating the reaction liquid after the reaction in the secondary reaction section into light liquid and heavy liquid is used as the separation means. This makes it possible to easily and reliably separate light and heavy liquids and efficiently produce fatty acid esters.
The mechanical separation means is a concept that means a separator using a specific gravity difference, such as a centrifugal separator, and there is no particular restriction on a specific device type.

Further, as in the fatty acid ester production apparatus according to claim 10 , the heavy liquid after liquid-liquid separation is distilled, and the low-boiling component mainly containing alcohol and water that cannot be separated in the separation means and remains By using a heavy liquid distillation means for separating a medium boiling point component mainly composed of fatty acid ester and a high boiling point component containing high boiling point impurities, the heavy liquid is reduced mainly with alcohol and water. It becomes possible to separate into a boiling point component, a medium boiling point component (target component) mainly composed of a fatty acid ester, and a high boiling point component containing a high boiling point impurity.

Further, as in the fatty acid ester production apparatus according to claim 11, a fatty acid contained in a small amount in a medium-boiling component mainly comprising a fatty acid ester obtained by distilling a heavy liquid after liquid-liquid separation, A high-quality fatty acid ester can be efficiently produced with less energy consumption by adopting a constitution comprising a fatty acid removing means for separating and removing by a neutralization reaction and an alkali removing means for washing and removing a small amount of remaining alkali. It becomes possible.

The apparatus for producing a fatty acid ester according to claim 12 , further comprising a low boiling point component removing means for removing low boiling point components mainly composed of water contained in the fatty acid ester after the fatty acid is removed by the fatty acid removing means by distillation. With this configuration, it is possible to obtain a high-purity fatty acid ester having a low content of low-boiling components such as moisture, and the present invention can be more effectively presented.

Further, as in the apparatus for producing a fatty acid ester according to claim 13 , the light liquid after the liquid-liquid separation is distilled to obtain a light liquid distillation means for separating the liquid into alcohol, water and glycerin. Can be separated into alcohol, water and glycerin components, and the active ingredient can be separated and recovered.
Examples of the light liquid distillation means (distillation method) include, but are not limited to, a method of performing distillation using a packed column, a flash distillation column, a thin film distillation column, and the like.

Moreover, the apparatus provided with the alcohol collection | recovery means which collect | recovers the alcohol isolate | separated by the light liquid distillation means, and the glycerol collection | recovery means which collect | recovers the glycerol separated by the light liquid distillation means like the fatty-acid-ester manufacturing apparatus of Claim By doing so, it becomes possible to collect high-purity alcohol and glycerin.
Furthermore, it is possible to reduce the drug cost by recycling the collected alcohol for the esterification reaction.
In addition, since the glycerol that is recovered does not contain a catalyst such as an alkali and can be recovered with high purity, it can be easily reused as auxiliary fuel or crude glycerol.

In addition, as in the apparatus for producing a fatty acid ester according to claim 15 , by setting the liquid space velocity in the tubular reactor in the range of 0.3 to 0.03 [1 / min], the esterification reaction is sufficiently performed. It becomes possible to do. It is desirable to adjust the liquid space velocity according to the state of the fatty acid raw material.
The liquid space velocity in the tubular reactor is preferably 0.3 to 0.03 [1 / min] because the reaction time is long when the liquid space velocity is less than 0.03 [1 / min]. Depending on the type of fatty acid, there is a high possibility of causing decomposition by heat, and when it exceeds 0.3 [1 / min], the reaction time is shortened and sufficient esterification reaction is not performed. .

Further, as in the fatty acid ester production apparatus according to claim 16 , by setting the temperature condition and pressure condition in the fatty acid raw material preheater and the mixing temperature riser to a range of temperature: 200 to 350 ° C. and pressure: 15 to 25 MPa. The fluid supplied to the tubular reactor is preheated so as to correspond to the reaction conditions in the tubular reactor, so that the tubular reactor can be reduced in size.

  When the fatty acid raw material is preheated under the above conditions in the fatty acid raw material preheater, not only preparation for supply to the mixing temperature riser is performed, but also the hydrolysis of fats and oils is usually performed by the contained moisture. Since glycerides, which are the main components, are decomposed into fatty acids, the esterification reaction can be promoted.

Further, as in the apparatus for producing a fatty acid ester according to claim 17 , by using a lower alcohol having 1 to 5 carbon atoms as an alcohol, the alcohol can be brought into a supercritical state under practical temperature and pressure conditions. It becomes possible, and this invention can be shown effectively.
Examples of the lower alcohol having 1 to 5 carbon atoms include methanol, ethanol, propanol, butanol, pentanol and the like.

The apparatus for producing a fatty acid ester according to claim 18 is used for producing a fatty acid ester to be used as a fuel. By using the apparatus for producing a fatty acid ester, an alkaline catalyst is not used, and the fatty acid ester is liberated. Fatty acid esters that are efficiently used as fuel (light oil substitute fuel) from fatty acid raw materials mainly composed of fatty acids (for example, fatty acid raw materials derived from at least one selected from the group consisting of vegetable oil, animal oil, vegetable oil or animal oil waste oil) Can be manufactured.

  Hereinafter, the features of the present invention will be described in more detail with reference to embodiments of the present invention.

  FIG. 1 shows a mixing means M for mixing and preheating alcohol as a solvent and a fatty acid raw material, a primary reaction part A1 in which a fatty acid raw material mainly composed of free fatty acids and an alcohol are esterified, and a reaction liquid reacted in the primary reaction part A1. FIG. 2 is a diagram showing a low boiling point component removing unit L that removes low boiling point components including moisture and excess alcohol generated in the primary reaction unit.

  FIG. 2 shows a secondary reaction part A2 in which an alcohol is added to the reaction liquid from which water has been removed in the low boiling point component removal part L, and an esterification reaction is performed again under the condition that the alcohol is in a supercritical state to produce a fatty acid ester. And a liquid-liquid separation means (separation means) B that performs liquid-liquid separation of the reaction liquid after the esterification reaction is performed in the secondary reaction section A2 and mechanically separates light and heavy liquids. It is.

  FIG. 3 is a diagram showing a light liquid distillation means C for distilling the light liquid separated by the liquid-liquid separation means B to recover alcohol and glycerin.

  Further, FIG. 4 shows that the heavy liquid separated by the liquid-liquid separation means B (FIG. 2) is distilled and separated by the heavy liquid distillation means D and the heavy liquid distillation means D for separating the low boiling point component and the high boiling point component. Fatty acid removal means E that separates and removes fatty acids contained in low-boiling components by a neutralization reaction, an alkali that removes alkali by adding water to a liquid mainly composed of fatty acid esters obtained by separating fatty acids by fatty acid removal means E It is a figure which shows the low boiling-point component removal means F etc. which remove the low boiling-point component which mainly has the water | moisture content contained in the removal means S and the liquid which has a fatty acid ester as a main component by distillation.

The apparatus for producing fatty acid esters shown in FIGS.
1) A mixing means M (FIG. 1) for mixing a fatty acid raw material mainly composed of free fatty acids and an alcohol (solvent) in a liquid state; and a mixed fluid mixed by the mixing means M, the alcohol is in a supercritical state. A primary reaction part A1 (FIG. 1) for continuously performing an esterification reaction by passing under conditions of temperature: 250 to 350 ° C. and pressure: 15 to 25 MPa;
2) Low boiling point component removal unit L that removes low boiling point components such as moisture and alcohol from the reaction liquid containing low boiling point components such as moisture and surplus alcohol produced in the primary reaction unit, reacted in the primary reaction unit A1. When,
3) Alcohol is added to the reaction liquid from which water has been removed by the low boiling point component removing unit L, and the alcohol becomes a supercritical state. The esterification reaction is again performed under the conditions of temperature: 250 to 350 ° C. and pressure: 15 to 25 MPa. A secondary reaction part A2 (FIG. 2) for generating a fatty acid ester,
4) The reaction liquid reacted in the primary reaction part A1 and the secondary reaction part A2 is subjected to liquid-liquid separation, and a light liquid and fatty acid ester mainly containing alcohol and glycerin and a heavy liquid containing high boiling impurities are mechanically separated. Liquid-liquid separation means B (FIG. 2) for separating
5) Light liquid distillation means (alcohol / glycerin recovery means) C (FIG. 3) for recovering alcohol and glycerin by distilling the light liquid separated by the liquid-liquid separation means B;
6) The heavy liquid distillation means D for distilling the heavy liquid separated by the liquid-liquid separation means B and separating it into a low boiling point component containing fatty acid ester as a main component and a high boiling point component containing high boiling point impurities (FIG. 4). When,
7) Fatty acid removing means E (FIG. 4) for separating and removing a small amount of fatty acid contained in the low boiling point component separated by heavy liquid distillation means D by neutralization reaction;
8) Alkali removing means S (FIG. 4) for removing alkali by adding water to a liquid mainly composed of a fatty acid ester obtained by separating fatty acids by fatty acid removing means E;
9) Low boiling point component removing means F (FIG. 4) for removing low boiling point components mainly containing water contained in a small amount in the liquid mainly composed of fatty acid ester after alkali removal by alkali removing means S (FIG. 4). I have.

  Examples of the mixing means M used in the fatty acid ester production apparatus include a method of dispersing fats and oils as fine oil droplets in an alcohol solvent using a highly functional in-line mixer for emulsification.

Further, the primary reaction section A1 (FIG. 1) is supplied from a fatty acid raw material preheater 3a for preheating a fatty acid raw material supplied from a fatty acid raw material tank 1 for storing a fatty acid raw material mainly composed of free fatty acids, and supplied from an alcohol (methanol) tank 2. An alcohol preheater 3b for preheating the alcohol to a temperature below the critical temperature, and a tubular reactor 4 for continuously performing the primary esterification reaction by passing a mixed fluid of the fatty acid raw material and the alcohol.
The alcohol preheater 3b includes a stirring mechanism (in-line mixer (not shown) in this embodiment), and the alcohol preheater 3a is mixed with the fatty acid raw material preheated in the fatty acid raw material preheater 3a and the alcohol in a liquid phase state. It can be made to function also as a mixing temperature riser which raises the temperature to a reaction temperature at which becomes a supercritical state.

  The tubular reactor 4 includes a tubular reactor body 4a in which a tube having a predetermined length is bent in a folded manner, and a mixed fluid (raw material fluid) of a fatty acid raw material and alcohol in a predetermined supercritical region of alcohol. The heater 4b is provided to raise the temperature until the temperature and pressure are reached or to maintain the temperature and pressure. As the type of the heater 4b, various types such as a double tube heating type using a heat medium or high-pressure steam and an electric heater type can be used, and there is no particular restriction on the configuration.

  A cooling unit 5 is provided on the outlet side of the tubular reactor 4 (specifically, on the outlet side of the alcohol preheater 3b). Providing this cooling unit 5 makes it possible to control the outlet temperature more appropriately. In addition, there is no special restriction | limiting in the specific structure when the presence or absence of the cooling part 5 and a cooling part are provided.

  The low boiling point component removal unit L includes a decompression system 36, a flash tank 37 that flashes and evaporates low boiling point components from the reaction liquid adjusted to a predetermined temperature and pressure by the decompression system 6, and a heater 38. In this low boiling point component removing portion L, low boiling point components such as moisture and excess alcohol generated in the primary reaction portion A1 are removed.

Further, the secondary reaction unit A2 includes a reaction liquid from which low-boiling components including water and excess alcohol generated by the primary reaction in the primary reaction unit A1 are removed, and alcohol supplied from the alcohol (methanol) tank 2. A secondary reaction mixing temperature riser 43a that raises the temperature to a reaction temperature at which the alcohol is in a supercritical state while being mixed in a liquid phase state, and a secondary fluid continuously by passing the mixed fluid of the reaction solution and the alcohol. A tubular reactor for secondary reaction 44 for performing an esterification reaction and a heat recovery unit 45 are provided.
The secondary reaction tubular reactor 44 includes a tubular reactor main body 44a in which a pipe having a predetermined length is bent in a folded manner, and a mixed fluid (raw fluid) of a fatty acid raw material and alcohol in a supercritical region of alcohol. A heater 44b is provided for heating up the temperature until the predetermined temperature and pressure are reached, or maintaining the temperature and pressure. As the type of the heater 44b, various types such as a double pipe heating type using a heat medium or high-pressure steam and an electric heater type can be used, and there is no particular restriction on the configuration.

  The separation means B mainly contains a light liquid mainly composed of alcohol and glycerin, a fatty acid ester, and a high-boiling-point impurity by liquid-liquid separation of the reaction liquid that has been subjected to the secondary esterification reaction by the secondary reaction part A2. The separator B serves to separate the heavy liquid as a component, and this separation means B mechanically liquid-liquid separates the reaction liquid supplied via the decompression system 6 and the buffer tank 7, as shown in FIG. The liquid-liquid separator 11 and its peripheral equipment are configured. In addition, as this liquid-liquid separator 11, it is possible to use a centrifugal separator and various mechanical separators other than the centrifugal separator.

  Further, alcohol for recovering alcohol and glycerin from the light liquid separated by the liquid-liquid separator 11 (FIG. 2), glycerin recovery means (light liquid distillation means) C (FIG. 3) is alcohol supplied from the buffer tank 12. , A preheater 13a for preheating a light liquid containing glycerin and water, a distillation column 13 for distilling the preheated light liquid to separate it into alcohol, glycerin and water, and a condenser 14 for condensing alcohol vapor as a fraction. And.

  The heavy liquid distillation means D is mainly composed of alcohol and water that cannot be separated in the liquid-liquid separator 11 from the heavy liquid containing the fatty acid ester and high-boiling impurities separated in the liquid-liquid separator 11. It functions to separate a low-boiling component, a medium-boiling component containing fatty acid ester as a main component, and a high-boiling component containing high-boiling impurities. As shown in FIG. A buffer tank 21 disposed on the liquid outlet side, a heavy liquid distiller 22 for distilling heavy liquid supplied from the buffer tank 21, and fatty acid esters and glycerin distilled from the heavy liquid distiller 22 (in liquid-liquid separation) And a condenser 23 that condenses glycerin mixed in the heavy liquid without being completely separated. A cold trap 24 is disposed downstream of the capacitor 23.

  As the heavy liquid distiller 22, a thin film descending distiller comprising a thin film descending heater and an evaporator is used. In the heavy liquid distiller 22, a low boiling point component, a fatty acid ester and glycerin (medium boiling point) are used. Component) is distilled off as a fraction, and unreacted substances and polymers (high-boiling impurities) are separated as a residue.

The fatty acid ester and glycerin distilled in the heavy liquid still 22 are condensed in the condenser 23, and the low boiling point component is condensed in the cold trap 24, so that the fatty acid ester and glycerin are separated from the low boiling point component. Is called.
The heavy liquid still 22 is not limited to the thin film descending heater and the evaporator as described above, and various types can be used.

  Further, the fatty acid removing means E functions to separate and remove a small amount of fatty acid constituting a part of the low boiling point component contained in the medium boiling point component mainly composed of the fatty acid ester condensed by the capacitor 23 by a neutralization reaction. As shown in FIG. 4, a neutralization reaction is performed with an alkali addition mechanism 25a for adding an alkali to a line for feeding a medium-boiling component mainly composed of a fatty acid ester condensed by a capacitor 23. And a separator 25 for mechanically separating the fatty acid soap produced by the reaction. In addition, as the separator 25, it is possible to use a centrifugal separator or various mechanical separators other than the centrifugal separator.

  In the fatty acid ester production apparatus of this embodiment, the main part of the heavy liquid distillation means D is configured to operate under reduced pressure, and the vacuum suction means 29 for that purpose is sealed water with a gas ejector. A vacuum pump is used. However, the type of the vacuum suction means 29 is not particularly limited, and other types can be used.

  Moreover, the alkali removal means S removes the alkali contained in the liquid which has the fatty acid ester which separated the fatty acid by the separator 25 constituting the fatty acid removal means E as a main component, and uses cleaning water (cleaning liquid). After the addition, the separator 30 is configured to be able to separate and remove moisture containing alkali.

The low boiling point component removing unit F functions to remove the low boiling point component by distilling out the low boiling point component mainly composed of water contained in a small amount of the fatty acid ester from which the alkali has been removed by the alkali removing unit S. As shown in FIG. 4, a buffer tank 26 for receiving a liquid mainly composed of a fatty acid ester exiting the separator 25, a heater 27a, a fatty acid ester heated by the heater 27a, and a small amount of low-boiling components. A flash tank 27 for removing the low boiling point component by flash evaporation of the liquid containing the liquid and a condenser 28 for condensing the vapor of the low boiling point component are provided.
And by this low boiling point component removal means F, high purity fatty acid ester will be collect | recovered by removing a low boiling point component.

The features of the present invention will be described more specifically with reference to the present invention and examples of the invention to which the present invention relates.

The first embodiment is an embodiment of the invention to which the present invention relates. In Example 1, the fatty acid raw material was processed under the following conditions using the fatty acid ester production apparatus configured as described above.

(1) Properties of fatty acid raw material Fatty acid content: about 90 to 92% by weight
Neutral oil content: about 6-9% by weight
Moisture content: about 1-2% by weight
(2) Type of alcohol (solvent) Industrial methanol (water content 0.2% or less)
(3) Primary reaction conditions Reaction temperature: 300 ° C
Reaction pressure: 20-22 MPa
Liquid space velocity: about 0.05 to 0.07 [1 / min]
Solvent addition rate: About 1.0 to 1.5 times the weight of fatty acid raw material
(4) Secondary reaction conditions Reaction temperature: 250 ° C
Reaction pressure: 20-22 MPa
Liquid space velocity: about 0.1-0.2 [1 / min]
Solvent addition rate: about 0.5 to 1.0 times the fatty acid raw material
(5) Composition of each reaction solution (analysis result)
Table 1 shows the compositions of the primary reaction solution and the secondary reaction solution.

  Then, from the secondary reaction solution, methanol as a solvent and glycerin as a by-product are removed, water is distilled off, and fatty acid esters recovered by removing high-boiling impurities are subjected to gas chromatography and gas chromatography / mass. Analyzes were made using analytical methods.

Composition of recovered fatty acid ester (analysis result)
Palmitic acid ester: 10.6%
Oleic acid ester: 39.5%
Stearic acid ester: 3.6%
Linoleic acid ester: 34.0%
Linolenic acid ester: 3.1%
Other fatty acid ester products: 2.6%
Glycerin: 0.02%
Moisture: 0.03%
Other: remaining

Physical properties of collected fatty acid esters (analysis results)
Density (15 ° C.): 0.8839 g / cm ³
Kinematic viscosity (50 ° C.): 3.735 mm ² / s
Flash point: 165 ° C
Clogging point: -4 ° C
Pour point: -2.5 ° C
Sulfur content: <0.01%
Residual carbon content: 0.01%
10% residual oil carbon content: 0.21%
Ash content: 0.002%
Cetane index: 59.5
Total calorific value: 39890 J / g
Cloud point: -3 ° C
Copper plate corrosion: 1a

  The fatty acid species of the detected fatty acid esters are mainly palmitic acid, oleic acid, linoleic acid, linolenic acid, and stearic acid as described above, and some other fatty acid esterified products that cannot identify the fatty acid species. It has been confirmed that a liquid containing about 98% of the components that are effective as alternative fuels (including substances effective as fuels other than fatty acid ester products) can be finally recovered by performing the distillation operation. It was done.

In addition, from the above analysis results, it was confirmed that the esterification reaction was sufficiently advanced, and substances other than the fatty acid ester were glycerin, trace water, and other monoglycerin fatty acid esters and diglycerin fatty acid esters. It was.
Moreover, it was confirmed from the said physical property investigated about the collect | recovered fatty acid ester that the fatty acid ester obtained by the method of the said Example 1 can be used as a light oil alternative fuel.

According to Example 1, it was confirmed that a fatty acid ester having a quality that can be used as a target light oil alternative fuel can be efficiently produced from a fatty acid raw material containing fatty acid as a main component.
The recovered methanol was also analyzed and confirmed to be of a quality that can be recycled.

The second embodiment is also an embodiment of the invention to which the present invention relates. In this Example 2, the fatty acid raw material which used the oil discharged | emitted from the refinement | purification process of an edible oil as a raw material was processed on the conditions according to the case of the said Example 1. FIG.

(1) Properties of fatty acid raw material Fatty acid content: about 75 to 83% by weight
Neutral oil content: about 16-24% by weight
Moisture content: about 0.8 to 2% by weight
(2) Type of alcohol (solvent) Industrial methanol (water content 0.2% or less)
(3) Primary reaction conditions Reaction temperature: 320 ° C
Reaction pressure: 20-22 MPa
Liquid space velocity: about 0.05 to 0.07 [1 / min]
Solvent addition rate: About 1.0 to 1.5 times the weight of fatty acid raw material
(4) Secondary reaction conditions Reaction temperature: 300 ° C
Reaction pressure: 20-22 MPa
Liquid space velocity: about 0.05 to 0.07 [1 / min]
Solvent addition rate: about 0.5 to 1.5 times the weight of fatty acid raw material
(5) Composition of each reaction solution (analysis result)
Table 2 shows the compositions of the primary reaction solution and the secondary reaction solution.

  Then, methanol and by-product glycerin are removed from the reaction solution, water is distilled off, and fatty acid esters recovered by removing high-boiling impurities are analyzed by gas chromatography and gas chromatography / mass spectrometry. The analysis by etc. was performed.

Composition of recovered fatty acid ester (analysis result)
Palmitic acid ester: 6.5%
Oleic acid ester: 51.5%
Stearic acid ester: 3.0%
Linoleic acid ester: 17.8%
Linolenic acid ester: 3.5%
Other fatty acid esterified products: 4.0%
Glycerin: 0.02%
Water content: 0.02%
Other: remaining

Properties of collected fatty acid esters (analysis results)
Density (15 ° C.): 0.8843 g / cm ³
Kinematic viscosity (50 ° C.): 3.760 mm ² / s
Flash point: 163 ° C
Clogging point: -3 ° C
Pour point: -2.5 ° C
Sulfur content: <0.01%
Residual carbon content: 0.02%
10% residual oil carbon content: 0.20%
Ash content: 0.002%
Cetane index: 59.8
Total calorific value: 39830 J / g
Cloud point: -2 ° C
Copper plate corrosion: 1a

  As a result of processing the fatty acid oil (fatty acid 70% by weight or more) using the oil discharged from the edible oil refining process as a raw material under the above conditions, it is confirmed that a result almost the same as that in Example 1 is obtained. It was done. The recovered methanol was also analyzed and confirmed to be of a quality that can be recycled.

  In Examples 1 and 2, methanol is used as the alcohol, but other lower alcohols having 2 to 5 carbon atoms, such as ethanol, propanol, butanol, and pentanol, can also be used.

1-4, the apparatus for producing fatty acid ester having the configuration not including the low boiling point component removing portion L composed of the decompression system 36, the flash tank 37, the heater 38, etc. (the fatty acid ester of the present invention) The production method of the fatty acid ester according to the present invention , that is, the fatty acid raw material mainly composed of free fatty acid and the alcohol are mixed, and the alcohol becomes a supercritical state in the primary reaction part A1. After performing the primary reaction (esterification reaction) under the conditions of temperature: 250 to 350 ° C. and pressure: 15 to 25 MPa, the reaction solution is brought to a temperature of 100 ° C. or lower (35 ° C. in this example) by the cooling means. In the secondary reaction part A2, the cooled reaction liquid is cooled to a supercritical state, temperature: 250 to 350 ° C., pressure: 15 By implementing a method to perform a secondary reaction (esterification reaction) under conditions of 25 MPa, to produce a fatty acid ester.

In this method, as a cooling means for cooling the reaction solution to a temperature of 100 ° C. or lower, those having various configurations such as heat exchange with a fatty acid raw material and a solvent, and heat recovery with a heat transfer oil are used. Is possible.
In Example 3, the same raw material as in Example 1 was used as the fatty acid raw material. The reaction conditions are as follows.

(1) Properties of fatty acid raw material Fatty acid content: about 90 to 92% by weight
Neutral oil content: about 6-9% by weight
Moisture content: about 1-2% by weight
(2) Type of alcohol (solvent) Industrial methanol (water content 0.2% or less)
(3) Primary reaction conditions Reaction temperature: 300 ° C
Reaction pressure: 18-23 MPa
Liquid space velocity: about 0.05 to 0.1 [1 / min]
Solvent addition rate: About 1.0 to 1.2 times the weight of fatty acid raw material
(4) Secondary reaction conditions Reaction temperature: 300 ° C
Reaction pressure: 18-23 MPa
Liquid space velocity: about 0.05 to 0.2 [1 / min]
Solvent addition rate: About 1.0 to 1.2 times the weight of fatty acid raw material
(5) Composition of each reaction solution As a result of analyzing the composition of the primary reaction solution and the secondary reaction solution, it was confirmed that the conversion rate to the methyl esterified product was almost the same as in Example 1.

  Then, from the secondary reaction solution, methanol as a solvent and glycerin as a by-product are removed, water is distilled off, and fatty acid esters recovered by removing high-boiling impurities are subjected to gas chromatography and gas chromatography / mass. Analyzes were made using analytical methods.

Composition of recovered fatty acid ester (analysis result)
Palmitic acid ester: 9.4%
Oleic acid ester: 36.5%
Stearic acid ester: 2.9%
Linoleic acid ester: 32.3%
Linolenic acid ester: 2.6%
Other fatty acid ester products: 2.9%
Glycerin: 0.02%
Moisture: 0.05%
Other: remaining

  The fatty acid species of the detected fatty acid esters are mainly palmitic acid, oleic acid, linoleic acid, linolenic acid, and stearic acid as described above, and some other fatty acid esterified products that cannot identify the fatty acid species. Finally, by performing the distillation operation, about 98% of components (including substances effective as fuels other than fatty acid ester products) that are finally effective as alternative fuels are finally obtained in the same manner as in Example 1. It was confirmed that the liquid contained in a proportion can be recovered.

In addition, from the above analysis results, it was confirmed that the esterification reaction was sufficiently advanced, and substances other than the fatty acid ester were glycerin, trace water, and other monoglycerin fatty acid esters and diglycerin fatty acid esters. It was.
Moreover, it was confirmed from the said physical property investigated about the collect | recovered fatty acid ester that the fatty acid ester obtained by the method of the said Example 3 can be used as a light oil alternative fuel.

From the above Example 3, it was confirmed that it is possible to efficiently produce a fatty acid ester having a quality that can be used as a target light oil alternative fuel from a fatty acid raw material containing fatty acid as a main component.
The recovered methanol was also analyzed and confirmed to be of a quality that can be recycled.

  As in Example 3, the reaction is also promoted by allowing the reaction (secondary reaction) to be performed again after cooling the primary reaction solution without removing the low-boiling components generated in the primary reaction step. However, when the low-boiling components generated in the primary reaction step are removed after the primary reaction step as in the methods for producing fatty acid esters in Examples 1 and 2 above, moisture, alcohol, etc. Since the low-boiling point impurities are removed, it is possible to expand the range in which the quality of the product can be controlled. The method of performing the secondary reaction after removing the low-boiling components generated in the primary reaction step is better. preferable.

Fatty acid esters were produced by the following methods (1) and (2), and the progress of the reaction in the primary reaction and the progress of the reaction in the secondary reaction were examined.
(1) A method according to the method of Example 1 above, wherein after the primary reaction, low-boiling components (methanol, moisture) are removed from the primary reaction solution, alcohol is added, and the secondary reaction is performed again ( this application) A method for producing a fatty acid ester according to the invention to which the invention relates ).
(2) After cooling to near room temperature (35 ° C. in this Example 4) without removing low-boiling components (methanol and moisture) from the primary reaction solution by a method according to the method of Example 3 above, the temperature rises again. A method of performing a secondary reaction by heating (a method for producing a fatty acid ester according to claim 2 of the present application).

In addition, the progress state of the primary reaction and the secondary reaction was performed by measuring the methyl esterification rate (ratio in which the fatty acid in the raw material becomes fatty acid methyl ester) and the acid value.
FIG. 5 shows the progress of the primary reaction and secondary reaction in the method (1).
Further, FIG. 6 shows the progress of the primary reaction in the method (2), and FIG. 7 shows the progress of the secondary reaction.

As shown in FIG. 5, after the primary reaction, the low boiling point component is removed from the primary reaction solution, alcohol is added, and the secondary reaction is performed again (method according to the method of Example 1). ), The methyl esterification rate after the primary reaction was 70 to 75%. Moreover, when the acid value of the reaction liquid after a primary reaction was measured, the value of the acid value was about 9-11.
Moreover, the methyl esterification rate after the secondary reaction was 80 to 85%. Furthermore, when the acid value of the reaction liquid after the secondary reaction was measured, the value of the acid value was about 2-3.
From the progress of the reaction and the value of the acid value shown in FIG. 5, the methyl esterification reaction is promoted by removing the low-boiling components from the primary reaction solution and then adding alcohol to cause the secondary reaction. Was confirmed.

  It is generally known that the presence of by-produced water in the methyl esterification reaction system inhibits the methyl esterification reaction, and the above results are obtained after removing water that is a low-boiling component after the primary reaction, The methyl esterification reaction was promoted by adding a secondary reaction by adding alcohol (methanol) again.

  As shown in FIG. 6, the method of (2) above, in which the secondary reaction is performed by cooling to near room temperature without removing low-boiling components (methanol, moisture) from the primary reaction solution and then raising the temperature again. In this case, the methyl esterification rate after the primary reaction was 70 to 75%. Moreover, when the acid value of the reaction liquid after a primary reaction was measured, the value of the acid value was about 9-11.

Moreover, as shown in FIG. 7, the methyl esterification rate after the secondary reaction was 75 to 80%. Moreover, when the acid value of the reaction liquid after a secondary reaction was measured, the value of the acid value was about 3-5.
From the reaction progress state and acid value shown in FIG. 7, after cooling to near room temperature without removing low-boiling components (methanol, moisture) from the primary reaction solution, the temperature was raised again to conduct the secondary reaction. It was confirmed that the methyl esterification reaction was promoted even when the reaction was allowed to occur.

  In the case of (2) above, the methyl esterification reaction is promoted when the difference between the temperature rise start temperature in the secondary reaction step and the reaction temperature in the secondary reaction is large. It is presumed that a dramatic change occurs in the contact state between a certain alcohol and the reaction solution after the primary reaction, and as a result, the methyl esterification reaction is promoted.

  In Examples 1 and 3, in the case where a fatty acid ester is produced from a fatty acid raw material containing fatty acid as a main component (Example 1), in Example 2 above, the fatty acid is obtained from the oil discharged from the edible oil refining process. Although the case where the fatty acid ester is produced from the raw material has been described as an example, it is also possible to process the fatty acid raw material obtained by converting other vegetable oil, animal oil, waste oil thereof or the like into a crude fatty acid.

The invention of the present application is not limited to the above-described embodiments and examples in other points as well, and temperature conditions and pressure conditions such as a primary reaction section, a secondary reaction section, a preheater , and a mixing temperature riser, and a primary reaction. With respect to the liquid space velocity in the case where the part is a tubular reactor, various applications and modifications can be made within the scope of the invention.

As described above, in the present invention, the fatty acid raw material mainly composed of free fatty acid and the alcohol are mixed, and the alcohol becomes a supercritical state. The temperature is 250 to 350 ° C. and the pressure is 15 to 25 MPa. after performing the reaction, cooling the first reaction mixture, after its, by re-performed reaction (secondary reaction), the reaction allowed to promote, it is possible to efficiently produce a fatty acid ester.

  Accordingly, the present invention relates to a field for producing a fatty acid ester having a quality that can be used as a light oil alternative fuel from a fatty acid raw material derived from at least one selected from the group consisting of vegetable oil, animal oil, vegetable oil or animal oil waste oil. It is possible to apply widely.

Mixing means M for mixing and preheating alcohol as a solvent and fatty acid raw material, primary reaction part A1 for esterifying reaction of fatty acid raw material mainly composed of free fatty acid and alcohol, and reaction liquid reacted in primary reaction part A1 It is a figure which shows the low boiling point component removal part L etc. which remove the low boiling point component containing the water | moisture content and excess alcohol which were produced | generated at the reaction process. A secondary reaction section A2 for adding a fatty acid to the reaction liquid from which water has been removed in the low boiling point component removal section L, causing the esterification reaction again under the condition that the alcohol is in a supercritical state, and generating a fatty acid ester; It is a figure which shows the liquid-liquid separation means (separation means) B etc. which carry out liquid-liquid separation of the reaction liquid after performing esterification reaction in next reaction part A2, and mechanically isolate | separate a light liquid and a heavy liquid. It is a figure which shows the light liquid distillation means C etc. which distill the light liquid isolate | separated by the liquid-liquid separation means B, and collect | recover alcohol and glycerol. Distilled heavy liquid separated by liquid-liquid separation means B (FIG. 2) and contained in low boiling point component, heavy liquid distillation means D for separating into high boiling point component, low boiling point component separated by heavy liquid distillation means D The fatty acid removing means E for separating and removing the fatty acid by the neutralization reaction, the alkali removing means S for removing the alkali by adding water to the liquid mainly composed of the fatty acid ester separated by the fatty acid removing means E, and the fatty acid It is a figure which shows the low boiling point component removal means F etc. which remove by distillation the low boiling point component which mainly contains the water | moisture content contained in the liquid which has ester as a main component. It is a figure which shows the progress state of a primary reaction and a secondary reaction in the method of adding alcohol after removing a low boiling point component (methanol, moisture) from a primary reaction liquid after a primary reaction, and performing a secondary reaction again. . It is a figure which shows the advancing state of the primary reaction in the method of cooling to near normal temperature, without removing a low boiling point component (methanol, water | moisture content) from a primary reaction liquid, and then heating up again and performing a secondary reaction. It is a figure which shows the advancing state of the secondary reaction in the method of cooling to near normal temperature, without removing a low boiling point component (methanol, water | moisture content) from a primary reaction liquid, and then heating up again and performing a secondary reaction.

A1 Primary reaction part A2 Secondary reaction part B Liquid-liquid separation means (separation means)
C Light liquid distillation means D Heavy liquid distillation means E Fatty acid removal means F Low boiling point removal means M Mixing means S Alkali removal means L Low boiling point removal part 1 Fatty acid raw material tank 2 Alcohol (methanol) tank 3a Fatty acid raw material preheater 3b Alcohol Preheater 4 Tube reactor 4a Reactor body 4b Heater 5 Cooling unit 6 Depressurization system 7 Buffer tank 11 Liquid-liquid separator 12 Buffer tank 13 Distillation tower 13a Preheater 14 Capacitor 21 Buffer tank 22 Heavy liquid distiller 23 Capacitor 24 Cold Trap 25 Separator 25a Alkali addition mechanism 26 Buffer tank 27 Flash tank 27a Heater 28 Condenser 29 Vacuum suction means 30 Separator 36 Depressurization system 37 Flash tank 38 Heater 43a Secondary reaction mixing temperature riser 44 Secondary reaction Type reactor 44a reactor body 44b heaters 45 heat recovery unit

Claims (18)

A fatty acid raw material containing free fatty acid as a main component and an alcohol are mixed, and the alcohol becomes a supercritical state. The esterification reaction is performed under the conditions of a temperature: 250 to 350 ° C. and a pressure: 15 to 25 MPa, and a fatty acid ester is obtained. A primary reaction step to be generated;
A cooling step of cooling the reaction solution reacted in the primary reaction step to a temperature of 100 ° C. or lower;
The reaction liquid cooled to a temperature of 100 ° C. or lower in the cooling step is subjected to esterification reaction again under the conditions of temperature: 250 to 350 ° C. and pressure: 15 to 25 MPa so that the alcohol becomes a supercritical state. A secondary reaction step for producing an ester. A method for producing a fatty acid ester, comprising: The method for producing a fatty acid ester according to claim 1 , wherein the fatty acid raw material is derived from at least one selected from the group consisting of vegetable oil, animal oil, vegetable oil or animal oil waste oil. The method for producing a fatty acid ester according to claim 1, wherein a ratio of free fatty acid in the fatty acid raw material is 70% by weight or more. A fatty acid raw material containing free fatty acid as a main component and an alcohol are mixed, and the alcohol becomes a supercritical state. The esterification reaction is performed under the conditions of a temperature: 250 to 350 ° C. and a pressure: 15 to 25 MPa, and a fatty acid ester is obtained. A primary reaction part to be generated;
A cooling section for cooling the reaction solution reacted in the primary reaction section to a temperature of 100 ° C. or lower;
The reaction liquid cooled to a temperature of 100 ° C. or lower in the cooling unit is subjected to esterification reaction again under the conditions of alcohol: supercritical state, temperature: 250-350 ° C., pressure: 15-25 MPa, and fatty acid. A device for producing a fatty acid ester, comprising: a secondary reaction unit for producing an ester. The primary reaction part, or the primary reaction part and the secondary reaction part, under the condition that the alcohol is in a supercritical state, mutually dissolve the fatty acid raw material or the mixed fluid of the reaction liquid after the primary reaction and the alcohol. The apparatus for producing a fatty acid ester according to claim 4, wherein the apparatus is a tubular reactor in which an esterification reaction is continuously performed by passing it through. 6. The apparatus for producing a fatty acid ester according to claim 5, further comprising an alcohol preheater that preheats the alcohol supplied to the tubular reactor to a temperature below the critical temperature. The fatty acid raw material preheater for preheating the fatty acid raw material, the alcohol preheater for preheating alcohol to a temperature below the critical temperature, the fatty acid raw material preheated in the fatty acid raw material preheater and the alcohol preheater, and the alcohol are mixed in a liquid phase state. The apparatus for producing a fatty acid ester according to any one of claims 4 and 5 , further comprising a mixing temperature-raising device that raises the temperature to a reaction temperature at which the alcohol is in a supercritical state. Separating means for liquid-liquid separation of the reaction liquid after the reaction in the secondary reaction section to separate into a light liquid mainly composed of alcohol and glycerin and a heavy liquid containing fatty acid ester and high boiling point impurities. The apparatus for producing a fatty acid ester according to any one of claims 4 to 7 , wherein: 9. The fatty acid ester according to claim 8 , wherein the separation means is mechanical separation means for mechanically separating the reaction liquid after the reaction in the secondary reaction section into the light liquid and the heavy liquid. Manufacturing equipment. Distilling the heavy liquid after the liquid-liquid separation, the low boiling point component mainly comprising alcohol and water remaining without being separated in the separation means, the medium boiling point component comprising fatty acid ester as the main component, and the high boiling point The apparatus for producing a fatty acid ester according to claim 8 or 9 , further comprising a heavy liquid distillation means for separating into a high-boiling component containing impurities. Fatty acid removing means for separating and removing a small amount of fatty acid contained in a medium-boiling component mainly composed of the fatty acid ester obtained by distilling the heavy liquid after the liquid-liquid separation by neutralization reaction with an alkaline aqueous solution, and a small amount The apparatus for producing a fatty acid ester according to claim 10 , further comprising alkali removing means for washing and removing the remaining alkali content. 12. The fatty acid according to claim 11 , further comprising a low-boiling component removing unit that removes a low-boiling component mainly containing water contained in the fatty acid ester after the fatty acid is removed by the fatty acid removing unit by distillation. Ester manufacturing equipment. The apparatus for producing a fatty acid ester according to any one of claims 8 to 12 , further comprising a light liquid distillation means for distilling the light liquid after the liquid-liquid separation to separate it into alcohol, water and glycerin. . 14. The fatty acid ester according to claim 13, further comprising an alcohol recovery means for recovering the alcohol separated by the light liquid distillation means and a glycerin recovery means for recovering the glycerin separated by the light liquid distillation means. Manufacturing equipment. The apparatus for producing a fatty acid ester according to any one of claims 5 to 14 , wherein a liquid space velocity in the tubular reactor is in a range of 0.3 to 0.03 [1 / min]. The temperature conditions and pressure conditions of the fatty acid raw material preheater and the mixing heater are as follows:
Temperature: 200-350 ° C
Pressure: 15-25MPa
The apparatus for producing a fatty acid ester according to any one of claims 7 to 15 , wherein the apparatus is in the range. The apparatus for producing a fatty acid ester according to any one of claims 4 to 16 , wherein a lower alcohol having 1 to 5 carbon atoms is used as the alcohol. The apparatus for producing a fatty acid ester according to any one of claims 4 to 17 , which is used for producing a fatty acid ester used as a fuel.

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