Facility for producing unsaturated alcohol, facility for producing fatty acid methyl ester, and method for producing fatty acid methyl ester

Abstract

This facility for producing an unsaturated alcohol includes: a first fatty acid methyl ester production facility which is provided with a tubular reactor; a second fatty acid methyl ester production facility which is provided with a bubble cap tower provided with a plurality of reaction stages; and a reduction reaction facility for bringing the fatty acid methyl ester into contact with hydrogen to obtain an unsaturated alcohol. The first fatty acid methyl ester production facility can produce an unsaturated fatty acid methyl ester using an oil / fat as a raw material. The second fatty acid methyl ester production facility can produce an unsaturated fatty acid methyl ester using a fatty acid as a raw material.

Description

Manufacturing equipment for unsaturated alcohol, manufacturing equipment for fatty acid methyl ester, and method for manufacturing fatty acid methyl ester

[0001] The present invention relates to manufacturing equipment for unsaturated alcohol, manufacturing equipment for fatty acid methyl ester, and a method for manufacturing fatty acid methyl ester. This application claims priority based on Japanese Patent Application No. 2024-226951 and Japanese Patent Application No. 2024-228056 filed on December 24, 2024, and incorporates all the descriptions described in the above Japanese patent applications.

[0002] As a method for manufacturing unsaturated alcohol, Patent Document 1 discloses equipment for manufacturing unsaturated alcohol by a reduction reaction using an unsaturated fatty acid alkyl ester as a raw material. However, there is no description of equipment and its method for manufacturing an unsaturated fatty acid alkyl ester that is a raw material for unsaturated alcohol.

[0003] As a method for manufacturing fatty acid methyl ester, there is a method in which animal fats and oils or vegetable fats and oils are heated with methyl alcohol in the presence of an acid or an alkali to perform transesterification. As an alkaline component, sodium hydroxide or potassium hydroxide is used. For example, Patent Document 2 discloses that before performing transesterification by alcoholysis, a pretreatment is performed in which raw material fats and oils are brought into contact with a lower alcohol at 60 to 140°C in the presence of an acid catalyst. It is disclosed that this pretreatment can reduce the amount of alkali required for transesterification and improve the yield of fatty acid alkyl ester.

[0004] Patent Document 3 discloses that as a manufacturing apparatus for fatty acid methyl ester, an apparatus for performing transesterification is constituted by a static mixer. As a specific configuration of the transesterification apparatus, a pipe filled with a large number of balls of various sizes is disclosed, and a form in which this pipe is coiled is also disclosed. Patent Document 3 discloses that by generating turbulent flow during transesterification, the reaction raw materials can quickly reach the reaction equilibrium.

[0005] Patent Document 4 discloses a method for producing fatty acid methyl esters, which involves reacting oil and fat with methanol and calcium hydroxide or calcium oxide, and using an amount of methanol in the reaction step such that the reaction mixture after the reaction step separates into two layers, with methanol as the main component of the upper layer and the upper layer being transparent. Patent Document 4 discloses that by using 10 times or more the theoretical amount of methanol, the amount of calcium component remaining in the obtained fatty acid methyl ester can be sufficiently reduced.

[0006] Furthermore, it is known that when industrially producing ester compounds, a foam tower is used as a distillation column for distillation purification of the reaction product. For example, Patent Document 5 discloses a method for producing a carboxylic acid ester, comprising: step A, in which an aliphatic carboxylic acid and an aliphatic alcohol are reacted in a reactor; step B, in which the reaction solution obtained in step A is supplied to a distillation column, the carboxylic acid ester produced from the top of the column and the by-product water are distilled off, and the unreacted aliphatic carboxylic acid is recovered from the bottom of the column; and step C, in which the unreacted aliphatic carboxylic acid recovered in step B is recycled to step A. The Patent Document discloses the use of a foam tower in step B.

[0007] Patent Document 6 describes an invention characterized by the use of a specific catalyst in the production of malonic acid diester, and discloses a method for continuously transesterifying dimethyl malonate using a bubble tower. An example in Patent Document 6 discloses a case in which dimethyl malonate and a transesterification catalyst are supplied from the top of the bubble tower, and ethanol is supplied from near the bottom of the tower to perform transesterification.

[0008] On the other hand, Patent Document 7 discloses a form of a tray tower equipped with a bubble bell. Patent Document 7 discloses a tray tower comprising a tray plate and a perforated plate provided on the tray plate, wherein a gas shutoff section is provided near the weir side of the perforated plate to block the flow of gas. The tray tower of Patent Document 7 discloses that the gas flow in the tray is controlled by the gas shutoff section, reducing pressure loss and improving gas-liquid stirring efficiency.

[0009] Japanese Patent Publication No. 2025-143923, Japanese Patent Publication No. 50-62926, Japanese Patent Publication No. 2001-524553, Japanese Patent Publication No. 2009-67904, Japanese Patent Publication No. 2010-241765, Japanese Patent Publication No. 2001-233823, Japanese Patent No. 5429083

[0010] The present invention aims to provide a manufacturing facility that can produce unsaturated alcohols stably on an industrial scale, and to provide a method for producing unsaturated alcohols using such a manufacturing facility.

[0011] The present invention aims to provide a manufacturing facility that suppresses the generation of by-products in the production of fatty acid methyl esters and enables the stable production of fatty acid methyl esters on an industrial scale, and to provide a method for producing fatty acid methyl esters using such a manufacturing facility.

[0012] Furthermore, as mentioned above, it is known that foam towers are used in the conventional production of ester compounds, while the form of tray towers has also been investigated. However, there is no concrete knowledge of equipment suitable for the production of fatty acid methyl esters using dehydration reactions, and the need for equipment that can produce fatty acid methyl esters continuously and efficiently continues. In view of this situation, the present invention aims to provide a production facility that can be implemented on an industrial scale and can continuously produce fatty acid methyl esters with a low acid value, and to provide a method for producing fatty acid methyl esters using such a production facility.

[0013] The unsaturated alcohol production equipment according to this disclosure includes a first fatty acid methyl ester production equipment equipped with a tubular reactor, a second fatty acid methyl ester production equipment equipped with a bubble tower having a plurality of reaction stages, and a reduction reaction equipment that obtains an unsaturated alcohol by contacting the fatty acid methyl ester with hydrogen.

[0014] The fatty acid methyl ester production equipment according to this disclosure comprises a first static mixer connected to a raw material introduction pipe, a first reaction unit connected downstream of the first static mixer, a first separator connected downstream of the first reaction unit, a second static mixer connected downstream of the first separator, a second reaction unit connected downstream of the second static mixer, and a second separator connected downstream of the second reaction unit. Each of the first reaction unit and the second reaction unit is a tubular reactor where the reaction section piping length (L) relative to the pipe diameter (p) satisfies L ≥ p × 8,000. The tubular reactor consists of a plurality of straight pipes and curved pipes connecting the straight pipes. The curved pipes include a first curved pipe and a second curved pipe having a curvature radius smaller than that of the first curved pipe. All of the plurality of straight pipes and the first curved pipe are arranged horizontally, and the second curved pipe is arranged horizontally and vertically.

[0015] The fatty acid methyl ester production apparatus according to this disclosure comprises a first raw material tank for containing fatty acids, a second raw material tank for containing methanol, a reaction tower with a first raw material supply line connected to the first raw material tank at the top and a second raw material supply line connected to the second raw material tank at the bottom, and a removal line for removing the product from the reaction tower. The reaction tower is a bubble tower having 40 to 55 reaction stages and is equipped with a first heat exchanger for heat exchange between the first raw material supply line and the removal line.

[0016] The unsaturated alcohol production equipment described herein provides a production facility that can produce unsaturated alcohols stably and on an industrial scale using unsaturated fatty acid methyl esters as raw materials.

[0017] The manufacturing equipment described herein can suppress the generation of by-products and produce fatty acid methyl esters stably and in an industrial scale.

[0018] The manufacturing equipment described herein provides a manufacturing facility that can be implemented on an industrial scale and continuously produce fatty acid methyl esters with a low acid value. Furthermore, a method for producing fatty acid methyl esters using such manufacturing equipment is also provided.

[0019] Figure 1 is a schematic diagram showing the configuration of the manufacturing equipment according to this disclosure. Figure 2 is a front view showing the first reaction unit of the manufacturing equipment according to this disclosure. Figure 3 is a side view showing the first reaction unit of the manufacturing equipment according to this disclosure. Figure 4 is a side view showing the first reaction unit of the manufacturing equipment according to this disclosure. Figure 5 is a front view showing the upper part of the second reaction unit of the manufacturing equipment according to this disclosure. Figure 6 is a side view showing the upper part of the second reaction unit of the manufacturing equipment according to this disclosure. Figure 7 is a side view showing the upper part of the second reaction unit of the manufacturing equipment according to this disclosure. Figure 8 is a front view showing the lower part of the second reaction unit of the manufacturing equipment according to this disclosure. Figure 9 is a side view showing the lower part of the second reaction unit of the manufacturing equipment according to this disclosure. Figure 10 is a side view showing the lower part of the second reaction unit of the manufacturing equipment according to this disclosure. Figure 11 is a cross-sectional view showing the configuration of straight tubes in the reaction unit of the manufacturing equipment according to this disclosure. Figure 12 is a cross-sectional view showing the configuration of straight tubes in the reaction unit of the manufacturing equipment according to this disclosure. Figure 13 is a schematic diagram showing the configuration of the manufacturing equipment according to this disclosure. Figure 14 is a schematic diagram showing the reaction tower of the manufacturing equipment according to this disclosure. Figure 15 is a schematic diagram showing the interior of the reaction tower of the manufacturing equipment according to this disclosure. Figure 16 is a schematic diagram showing the interior of the reaction tower of the manufacturing equipment according to this disclosure.

[0020] [Summary of Embodiments] First, embodiments of the production equipment for unsaturated alcohols, production equipment for fatty acid methyl esters, and production methods according to this disclosure will be listed and described. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more, B or less."

[0021] The unsaturated alcohol production equipment according to this disclosure includes a first fatty acid methyl ester production equipment equipped with a tubular reactor, a second fatty acid methyl ester production equipment equipped with a bubble tower having a plurality of reaction stages, and a reduction reaction equipment that obtains an unsaturated alcohol by contacting the fatty acid methyl ester with hydrogen.

[0022] For example, as shown in Patent Document 1, unsaturated alcohols are produced by the reduction reaction of unsaturated fatty acid alkyl esters, more specifically, unsaturated fatty acid methyl esters. Unsaturated fatty acid methyl esters, which are raw materials for unsaturated alcohols, can be produced using oils and fatty acids as raw materials, but there is little concrete knowledge about manufacturing equipment that can produce unsaturated fatty acid methyl esters industrially and stably. The unsaturated alcohol manufacturing equipment according to this disclosure includes a first fatty acid methyl ester manufacturing equipment equipped with a tubular reactor, and a second fatty acid methyl ester manufacturing equipment equipped with a bubble tower having multiple reaction stages. In the first fatty acid methyl ester manufacturing equipment, fatty acid methyl esters are produced using oils and fats as raw materials. In the second fatty acid methyl ester manufacturing equipment, fatty acid methyl esters are produced using fatty acids as raw materials. By providing these facilities, a manufacturing equipment is provided that can produce unsaturated alcohols stably and on an industrial scale using unsaturated fatty acid methyl esters as raw materials.

[0023] The first fatty acid methyl ester production apparatus according to this disclosure comprises a first static mixer connected to a raw material introduction pipe, a first reaction unit connected downstream of the first static mixer, a first separator connected downstream of the first reaction unit, a second static mixer connected downstream of the first separator, a second reaction unit connected downstream of the second static mixer, and a second separator connected downstream of the second reaction unit. Each of the first and second reaction units is a tubular reactor where the reaction section piping length (L) relative to the pipe diameter (p) is L ≥ p × 8,000. The tubular reactor consists of a plurality of straight pipes and curved pipes connecting the straight pipes. The curved pipes include a first curved pipe and a second curved pipe having a smaller curvature radius than the first curved pipe. All of the plurality of straight pipes and the first curved pipe are arranged horizontally, and the second curved pipe is arranged horizontally and vertically.

[0024] For example, as disclosed in Patent Document 3, a reaction apparatus equipped with numerous balls or baffles inside a reaction tube has been proposed as a means of generating turbulence to promote mixing of raw material oils and methanol in the production of fatty acid methyl esters. However, from the viewpoint of maintainability, reaction efficiency, and cost, there is a continuing need for an apparatus that can carry out transesterification reactions industrially and stably. Under these circumstances, studies on reaction apparatuses have been conducted, and it has been found that by adopting a tubular reactor and further configuring the tubing of the tubular reactor as described above, it is possible to fit long piping into a limited space, suppress the generation of by-products, and produce fatty acid methyl esters stably and on an industrial scale. The manufacturing equipment according to this disclosure has a reaction tube length that is large relative to the diameter of the reaction tube, and a configuration in which multiple straight tubes are connected via curved tubes. It is believed that the manufacturing equipment according to this disclosure ensures mixing performance by having a long reaction tube and multiple curved sections, and that transesterification is carried out efficiently and stably.

[0025] In the manufacturing equipment described above, the multiple straight pipes may be of the same length and arranged to form multiple stages spaced equally apart in the vertical direction. The uppermost stage and the straight pipes belonging to each of the uppermost stages may be connected by the first curved pipe. With this configuration, the reaction raw materials flowing through the piping can be mixed stably and reliably, the temperature can be controlled, and the transesterification reaction can proceed.

[0026] In the manufacturing equipment described above, the plurality of straight pipes may include single-walled straight pipes and double-walled straight pipes equipped with a temperature-controlled jacket through which a heat transfer medium flows. The plurality of stages may include stages composed of single-walled straight pipes and stages composed of double-walled straight pipes. This configuration makes it possible to appropriately heat the reaction materials flowing through the piping and provides equipment that is easy to maintain and suitable for industrial operation.

[0027] In the manufacturing equipment described above, the number of stages ranges from 5 to 11, and of the stages, the uppermost stage, the lowermost stage, and at least one stage between the uppermost and lowermost stages may be stages made of double pipes. Alternatively, in the manufacturing equipment described above, the number of stages may be 11, and the uppermost stage, the fourth stage, and the seventh stage may be stages made of double pipes. By separating the stages from those equipped with a temperature control function and the stages without it, and by arranging the stages equipped with a temperature control function at approximately equal intervals, more appropriate temperature control can be achieved.

[0028] In the above-mentioned manufacturing equipment, each of the first reaction unit and the second reaction unit may be a device equipped with 96 of the straight pipes. With such a piping configuration, the necessary and sufficient transesterification reaction can be generated, and fatty acid methyl esters can be produced in good yield.

[0029] The method for producing fatty acid methyl esters according to this disclosure is a method for producing fatty acid methyl esters in the fatty acid methyl ester production facility described above. The production method includes: a first transesterification step of introducing raw material oil and methanol into the first reaction unit through the raw material introduction pipe and performing transesterification; a first separation step following the first transesterification step of separating the product fraction and a glycerin-containing brine fraction in the first separator; a second transesterification step following the first separation step of further adding methanol to the product fraction and introducing it into the second reaction unit and performing transesterification; and a second separation step following the second transesterification step of separating the product fraction and a glycerin-containing brine fraction in the second separator. According to this production method, a sufficient transesterification reaction can be produced under mild reaction conditions, and fatty acid methyl esters can be produced in good yield.

[0030] In the above manufacturing method, the amount of methanol added in the first transesterification step may be 1.5 times the theoretical reaction amount in moles or more, preferably 2 times the theoretical reaction amount in moles or more, and particularly preferably 2.2 times or more. Here, the theoretical reaction amount is the amount of methanol required to convert all of the raw material oil into fatty acid methyl esters. Furthermore, the molar ratio of the amount of raw material oil charged to the amount of methanol charged in the first transesterification step may be 2 to 10 moles of methanol per mole of raw material oil charged, preferably 5 to 10 moles, and more preferably 8 to 9 moles. The number of moles of raw material oil can be determined from the average molecular weight of the raw material oil. The average molecular weight of the raw material oil can be determined according to known methods, but for example, it can be determined by assuming that all of the raw material oil is triglycerides and using the saponification value and acid value.

[0031] In the second transesterification step, the amount of methanol added is preferably 1 to 1.1 times the theoretical reaction amount in moles. Furthermore, the molar ratio of the amount of raw material oil and methanol added in the second transesterification step may be 1 to 5 moles of methanol per mole of raw material oil, preferably 1.1 to 3 moles, and more preferably 2 to 3 moles. According to these manufacturing methods, a sufficient transesterification reaction can be produced, and fatty acid methyl esters can be produced in good yield.

[0032] Furthermore, the production apparatus for the second fatty acid methyl ester according to the present disclosure comprises a first raw material tank for containing fatty acids, a second raw material tank for containing methanol, a reaction tower with a first raw material supply line connected to the first raw material tank at the top and a second raw material supply line connected to the second raw material tank at the bottom, and a removal line for removing the product from the reaction tower. The reaction tower is a bubble tower having 40 to 55 reaction stages and is equipped with a first heat exchanger for heat exchange between the first raw material supply line and the removal line.

[0033] According to the aforementioned manufacturing equipment, the fatty acid supplied from the top of the reaction tower and the methanol supplied from the bottom of the reaction tower are thoroughly mixed in the reaction tower, allowing for the stable production of fatty acid methyl esters with a low acid value. Furthermore, in the first heat exchanger, the heat contained in the reaction product (fatty acid methyl ester) discharged from the reaction tower is used to heat the raw material fatty acid. This configuration improves energy utilization efficiency and reduces energy consumption, resulting in a manufacturing facility with reduced energy consumption.

[0034] In the fatty acid methyl ester production apparatus, the bubble tower is preferably constructed by stacking reaction stages vertically, each having a height of 30 to 45 cm and a diameter of 50 to 70 cm. The bubble tower comprises a first cylinder rising from the bottom surface of the reaction stage, a second cylinder rising from the bottom surface of the reaction stage and being shorter in height than the first cylinder, and a third cylinder positioned inside the first cylinder, penetrating the bottom surface of the reaction stage and having a portion that protrudes upward from the bottom surface and a portion that protrudes downward from the bottom surface. The third cylinder is preferably installed so as to be inserted into the second cylinder of the reaction stage one level below. The third cylinder is a downcomer, and by configuring the downcomer in this form, splashing of liquid flowing down from the upper reaction stage can be prevented, and gas-liquid mixing can be reliably carried out in the subsequent reaction stage. Specifically, if the reaction stage is 40 cm high and 60 cm in diameter, the first cylinder may be 38 cm high and 13 cm in diameter, and the second cylinder may be 30 cm high and 13 cm in diameter. In this case, the third cylinder may have a portion that protrudes 25 cm above the bottom surface, a portion that protrudes 37 cm below the bottom surface, and an overall length of 62 cm.

[0035] In the fatty acid methyl ester production apparatus described above, it is preferable that each of the first cylinder and the second cylinder has a notched hole formed in the peripheral wall of the rising portion from the bottom surface of the reaction stage.

[0036] In the fatty acid methyl ester production apparatus described above, it is preferable that each of the reaction stages is equipped with 10 to 24 foam bells.

[0037] The method for producing fatty acid methyl esters according to this disclosure is a method carried out in the fatty acid methyl ester production facility described above. The production method according to this disclosure includes an esterification step in which a fatty acid is introduced from the first raw material tank into the reaction tower and methanol is introduced from the second raw material tank into the reaction tower, and the fatty acid and methanol are brought into contact in the reaction tower. In the first heat exchanger, after the esterification step, heat exchange is performed between the reactant discharged from the reaction tower and flowing through the extraction line and the fatty acid discharged from the first raw material tank and flowing through the first raw material supply line.

[0038] In the above manufacturing method, it is preferable to include a step of adding iron powder to the fatty acid contained in the first raw material tank.

[0039] In the esterification step, it is preferable that the ratio of the amount of fatty acid charged to the reaction tower per unit time to the amount of methanol charged to the reaction tower is 1:1.8 to 1:3.0 (molar ratio).

[0040] [Specific Examples of Embodiments] Next, a specific example of an embodiment of the manufacturing equipment and manufacturing method according to this disclosure will be described with reference to the attached drawings. In this disclosure, the same or corresponding parts in the drawings are denoted by the same reference numerals, and their descriptions will not be repeated. Also, in the following description, "upper" and "lower" mean relatively above or below along the vertical direction.

[0041] (First Fatty Acid Methyl Ester Production Equipment) Figure 1 is a schematic diagram showing the configuration of a fatty acid methyl ester production equipment according to the present disclosure. The production equipment shown in Figure 1 is a production equipment for the first fatty acid methyl ester. Referring to Figure 1, the production equipment 1 comprises a raw material introduction pipe 41 connected to a raw material oil tank 31, two reaction units, a first reaction unit 10 and a second reaction unit 20, connected to the raw material introduction pipe 41, and a purification unit 50 for separating and purifying the target product, the fatty acid methyl ester. The detailed configurations of the first reaction unit 10 and the second reaction unit 20 will be described later. The production equipment 1 is a two-stage reaction equipment including a first reaction section consisting of a first static mixer 12, a first reaction unit 10 and a first separator 15, and a second reaction section consisting of a second static mixer 22, a second reaction unit 20 and a second separator 25.

[0042] The raw material introduction piping 41 is connected to the first static mixer 12, and the first reaction unit 10 is connected downstream of the first static mixer 12. Piping 42 is connected to the outlet side of the first reaction unit 10, and piping 42 is connected to the first separator 15. Piping 43, which is connected to the outlet side of the first separator 15, is connected to the second static mixer 22. The outlet piping of the second static mixer 22 is connected to the second reaction unit 20. Piping 44 is connected to the outlet side of the second reaction unit 20, and piping 44 is connected to the second separator 25. Piping 45, which is connected to the outlet side of the second separator 25, is connected to the purification section 50.

[0043] The purification section 50 is a distillation apparatus, specifically consisting of a primary distillation column 51, a main distillation column 52, and a concentration column 53 connected in that order. The fraction from the primary distillation column 51 is introduced into the main distillation column 52, and the fraction from the main distillation column 52 is introduced into the concentration column 53. The specific configuration of the purification section 50 will be described later.

[0044] The raw material introduction pipe 41 is connected to the raw material oil and fat tank 31 and the methanol tank 32. Although not shown, an alkali inlet for introducing an alkali as a catalyst is also provided. The raw material oil and fat, methanol, and alkali are introduced into the first static mixer 12 through the raw material introduction pipe 41. In the first static mixer 12, the reaction raw materials are stirred and mixed to become a turbulent flow and are introduced into the first reaction unit 10. The reaction raw materials cause transesterification while passing through the first reaction unit 10.

[0045] From the reaction mixture that has exited the first reaction unit 10, the glycerin water is separated in the first separator 15. The glycerin water contains glycerin produced by the transesterification reaction and a water-soluble alkali catalyst. The product fraction taken out from the first separator 15 is taken out through the pipe 43. The product fraction contains unreacted raw material oil and fat and the produced fatty acid methyl ester. The methanol tank 33 is connected to the pipe 43, is mixed with the product fraction taken out from the first separator 15, is stirred and mixed in the second static mixer 22, and is introduced into the second reaction unit 20. The reaction raw materials cause further transesterification while passing through the second reaction unit 20. The first separator 15 is an oil-water separation tank, and the glycerin water can be taken out through a line connected to the bottom. The pipe 42, which is an introduction line, and the pipe 43, which is a take-out line, are connected to the side surface of the tank portion of the first separator 15.

[0046] The reaction mixture taken out from the second reaction unit 20 through the pipe 44 is introduced into the purification unit 50 after the sweet water is separated again in the second separator 25. The second separator 25 is an oil-water separation tank having the same configuration as the first separator 15. As described above, the purification unit 50 preferably includes a debutanizer 51, a main fractionator 52, and a concentrator 53, and further includes an atmospheric pressure purification device and a vacuum purification device not shown in the figure. In the purification unit 50, first, it is preferable that water and methanol, which are low-boiling components, are distilled off in the atmospheric pressure purification device and the vacuum purification device. Subsequently, chlorine-containing oxides, which are low-boiling components, are removed in the debutanizer 51. Since the mixing of chlorine-containing oxides into the fatty acid methyl ester may inhibit further reactions using the fatty acid methyl ester as a raw material, it is preferable that the chlorine-containing oxides are surely removed in the debutanizer 51.

[0047] In the main fractionator 52, the fatty acid methyl ester is taken out as a distillation component. The fraction in the main fractionator 52 is introduced into the concentrator 53 and heated again, and high-boiling components including oil polymer and wax content are separated and discharged as pitch. On the other hand, the fatty acid methyl ester component mixed in the fraction is introduced again from the concentrator 53 into the main fractionator 52.

[0048] The first reaction unit 10 and the second reaction unit 20 will be described. Both the first reaction unit 10 and the second reaction unit 20 are tubular reactors in which a large number of long pipes are arranged in multiple stages. The first reaction unit 10 and the second reaction unit have different reaction path lengths. Fig. 2 is a schematic front view of the first reaction unit 10. Fig. 3 is a schematic side view of the first reaction unit 10 and is a view taken along the arrow III-III in Fig. 2. Fig. 4 is a schematic side view of the first reaction unit 10 and is a view taken along the arrow IV-IV in Fig. 2.

[0049] Referring to Figure 2, the first reaction unit 10 is a tubular reactor in which numerous long pipes are arranged in multiple stages on a rack 7 laid on a frame or on the factory floor. The numerous long pipes are connected to each other to form a single flow path. The first reaction unit 10 is stacked in seven stages. For the sake of explanation, the top stage will be called the first stage, and the subsequent stages will be numbered sequentially from top to bottom, with the bottom stage being called the seventh stage. The rack 7 includes a base 71 extending horizontally and support columns 72 extending vertically, and the pipes constituting each stage are supported by the support columns 72. In Figures 3 and 4, only the frame of the rack 7 is shown, and details are omitted.

[0050] The first reaction unit 10 includes a plurality of straight tubes 11, which are connected to each other via either a first curved tube 13 or a second curved tube 14. In the example shown in Figure 2, the radius of the curved section of the first curved tube 13 is 150 mm. The radius of the curved section of the second curved tube 14 is 75 mm. In other words, the curved radius of the first curved tube 13 is larger than the curved radius of the second curved tube 14.

[0051] Referring to Figures 2 to 4, in the first reaction unit 10, all of the multiple straight pipes 11 and all of the first curved pipes 13 are arranged horizontally. Here, "horizontal direction" means that the flow path extends horizontally. On the other hand, the second curved pipes 14 can be arranged horizontally or vertically. All stages in the first reaction unit 10 are connected by the second curved pipes 14, so that each stage is spaced equally apart from the others.

[0052] Referring to Figures 3 and 4, the first reaction unit 10 has an inlet 16 at the uppermost end and an outlet 17 at the lowermost end, opposite to the uppermost end. The flow path of the first reaction unit 10 is configured from top to bottom. In the uppermost (first stage), fourth stage, and seventh stage, the straight pipes 11 are connected by a first curved pipe 13. In the second, third, fifth, and sixth stages, the straight pipes 11 are connected by a second curved pipe 14. There are six straight pipes in each of the uppermost, fourth, and seventh stages. There are eleven straight pipes in each of the second, third, fifth, and sixth stages. The first reaction unit 10 as a whole is equipped with 62 straight pipes 11.

[0053] The straight pipe 11 is made of Sch40, with a pipe diameter (inner diameter) p of approximately 41 mm and a length of approximately 5500 mm. The total length of the straight pipe 11 in the first reaction unit 10 is approximately 341 m. Furthermore, the length of the curved sections is also included in the total length of the piping in the reaction unit. Therefore, the reaction section piping length L and pipe diameter p in the reaction unit satisfy L ≥ p × 8,000. By flowing the reaction raw materials at a high flow rate through such small-diameter, long piping, a reaction apparatus with excellent stirring efficiency and heat exchange efficiency can be constructed, and fatty acid methyl esters can be produced in high yield.

[0054] The second reaction unit 20 is a unit equipped with a reaction tube divided into two parts, an upper section 20A and a lower section 20B, and has a longer flow path than the first reaction unit 10. Figure 5 is a schematic front view of the upper section 20A of the second reaction unit 20. Figure 6 is a view taken along the arrow VI-VI in Figure 5. Figure 7 is a view taken along the arrow VII-VII in Figure 5.

[0055] Referring to Figure 5, the upper section 20A of the second reaction unit 20 is a tubular reactor in which numerous long pipes are arranged in multiple stages on a rack 7, and the configuration of the rack 7, including the base 71 and support columns 72, is the same as described above. The upper section 20A is stacked in 11 stages at equal intervals. The upper section 20A includes a plurality of straight pipes 11, a first curved pipe 13, and a second curved pipe 14. The straight pipes 11 are made of Sch40, with a pipe diameter (inner diameter) p of approximately 41 mm and a length of approximately 4010 mm. The first curved pipe 13 and the second curved pipe 14 are the same as those in the first reaction unit 10.

[0056] Referring to Figures 6 and 7, the upper stage 20A has an inlet 16 at the uppermost end and an outlet 17 at the lowermost end, opposite to the uppermost end. The flow path of the upper stage 20A is configured from top to bottom overall. In the uppermost (first stage), fourth stage, and seventh stage, the straight pipes 11 are connected by the first curved pipe 13. In the second, third, fifth, and sixth stages, the straight pipes 11 are connected by the second curved pipe 14. There are six straight pipes each in the uppermost, fourth, and seventh stages. There are eleven straight pipes each in the second, third, fifth, and sixth stages. The entire first reaction unit 10 is equipped with 96 straight pipes 11. The total length of the straight pipes 11 is approximately 384 m.

[0057] Figure 8 is a schematic front view of the lower section 20B of the second reaction unit 20. Figure 9 is a view taken along the line IX-IX in Figure 8. Figure 10 is a view taken along the line X-X in Figure 8. Referring to Figure 8, the lower section 20B of the second reaction unit 20 is a tubular reactor in which numerous long pipes are arranged in multiple stages on a rack 7, and the configuration of the rack 7, including the base 71 and the support columns 72, is the same as that described previously. The lower section 20B is stacked in five stages at equal intervals. The lower section 20B includes a plurality of straight pipes 11, a first curved pipe 13, and a second curved pipe 14. The straight pipes 11 are made of Sch20, with a pipe diameter (inner diameter) p of approximately 62 mm and a length of approximately 5500 mm. The first curved pipe 13 and the second curved pipe 14 are the same as those in the first reaction unit 10.

[0058] Referring to Figures 9 and 10, the lower section 20B has an inlet 16 at the end of the uppermost section and an outlet 17 at the end of the lower section opposite to the end of the uppermost section. The flow path of the lower section 20B is configured from top to bottom overall. In the uppermost (first) section, the fourth section, and the fifth section, the straight pipes 11 are connected by the first curved pipe 13. In the second section and the third section, the straight pipes 11 are connected by the second curved pipe 14. There are six straight pipes in each of the uppermost, fourth, and fifth sections. There are eleven straight pipes in each of the second and third sections. The entire first reaction unit 10 is equipped with 40 straight pipes 11. The total length of the straight pipes 11 is approximately 220 m.

[0059] In the upper section 20A and lower section 20B of the first reaction unit 10 and the second reaction unit 20, respectively, the straight pipe 11 may include a single pipe 18 and a double pipe 19. Figures 11 and 12 show cross-sectional views of the straight pipes, respectively. Referring to Figure 11, the single pipe 18 is a steel pipe having flanges 88 at both ends. The material of the single pipe 18 is, for example, carbon steel. Referring to Figure 12, the double pipe 19 has flanges 89 at both ends and comprises a central pipe section 83 through which reaction materials flow, and a jacket 84 surrounding the central pipe section 83 through which a heat transfer medium flows. The jacket 84 has a heat transfer medium inlet 85 and a heat transfer medium outlet 86 at both ends in the longitudinal direction. The heat transfer medium is not particularly limited; for example, when lowering the temperature of the reaction materials in the reaction unit, water can be used as a cooling medium. When raising the temperature of the reaction materials in the reaction unit, steam can be used as a heating medium.

[0060] Each of the first reaction unit 10 and the second reaction unit 20 (upper stage 20A, lower stage 20B) is equipped with both single-walled tubes 18 and double-walled tubes 19. Referring to Figures 2 to 4, the uppermost, fourth, and seventh stage straight tubes 11 of the first reaction unit 10 are made of double-walled tubes 19. The second, third, fifth, and sixth stage straight tubes 11 are single-walled tubes 18. Referring to Figures 5 to 7, the upper stage 20A of the second reaction unit 20 is made of double-walled tubes 19. The second, third, fifth, sixth, eighth, and ninth stage straight tubes 11 are single-walled tubes 18. Referring to Figures 8 to 10, the lower section 20B of the second reaction unit 20 has double-walled straight tubes 19 in the uppermost, fourth, and lowermost sections. The straight tubes 11 in the second and third sections are single-walled 18. This configuration allows for more efficient heat exchange and reliable temperature control of the reactants.

[0061] The pipe diameters and lengths in the reaction unit described above are examples only and are not limited to those examples. For example, the unit can be equipped with 30 to 100 straight pipes, each approximately 25A to 60A in diameter and 2000 mm to 6000 mm in length, and can be appropriately selected according to the scale and purpose of the equipment.

[0062] (Manufacturing Method) (Raw Materials) The method for producing fatty acid methyl esters according to this disclosure is carried out using oils and fats and methanol as raw materials. The raw material oils and fats may be natural oils such as animal oils and vegetable oils. Examples of vegetable oils and fats may be coconut oil, palm kernel oil, palm oil, olive oil, soybean oil, low-erucine rapeseed oil, high-erucine rapeseed oil, safflower oil, corn oil, cottonseed oil, sunflower oil, rice bran oil, linseed oil, coconut oil, oak oil, almond oil, peanut oil, hazelnut oil, grapeseed oil, etc. Examples of animal oils and fats may be beef tallow, pork tallow, chicken tallow, whale oil, sardine oil, mackerel oil, shark oil, liver oil, etc. Mixtures of these oils and fats may also be used. Typically, the raw material oils and fats may be a mixture of beef tallow and pork tallow.

[0063] It is preferable to use raw oils and fats with an acid value of approximately 0.8 to 8 mg KOH / g. By using oils and fats with an acid value in this range, fatty acid methyl esters can be reliably obtained in good yield. The raw oils and fats may contain approximately 0.4 to 4.2% free acid.

[0064] For transesterification reactions, either an alkali or an acid is used as a catalyst, but an alkali is preferred. Examples of alkaline catalysts include sodium-based catalysts such as sodium hydroxide and sodium methoxide, and potassium-based catalysts such as potassium hydroxide and potassium methoxide. Solid alkali catalysts such as highly active calcium oxide or activated calcium oxide may also be used. Of these, sodium hydroxide is preferred. Sodium hydroxide is preferably added to the reaction system in a dissolved state in methanol. For example, a NaOH / 10% methanol solution can be used as the catalyst solution.

[0065] (Manufacturing Process) The method for producing fatty acid methyl esters according to the present disclosure is preferably carried out in the manufacturing equipment described above. The manufacturing method includes a first transesterification step of introducing raw material oil and methanol into a first reaction unit and performing transesterification, and a first separation step following the first transesterification step of separating a product fraction and a glycerin-containing hydrate fraction in a first separator. Furthermore, following the first separation step, the method includes a second transesterification step of adding methanol to the product fraction and introducing it into a second reaction unit and performing transesterification, and a second separation step following the second transesterification step of separating a product fraction and a glycerin-containing hydrate fraction in a second separator.

[0066] The raw material oil to be used in the first transesterification step may be preheated in a preheater. The preheating temperature may be around 50 to 60°C. Methanol and a catalyst solution are added to the preheated raw material oil and mixed in a static mixer. As an example, the raw material can be continuously supplied to the first transesterification step by supplying 3500 kg / h of raw material oil, 715 kg / h of methanol, and 108 kg / h of the NaOH / 10% methanol catalyst solution. If the average molecular weight of the 3500 kg of raw material oil is approximately 870 and the molecular weight of methanol is 32, then the supply rate of raw material oil and methanol per unit time is 4.0 kmol / h:25.2 kmol / h, meaning that methanol is supplied at a ratio of 6.3 moles per mole of raw material oil. As another example, the first transesterification step may be carried out with a supply rate of 2500 kg / h for raw oil and fat, a supply rate of 680 kg / h for methanol, and a supply rate of 102 kg / h for the catalyst solution, which is a NaOH / 10% methanol solution. In this case, the amount of methanol supplied per mole of raw oil and fat would be approximately 8.6 moles.

[0067] The first transesterification step is carried out at a temperature of 55°C or lower. For example, the outlet temperature of the first reaction unit may be around 45 to 55°C. The reaction temperature in the first transesterification step can be controlled by supplying water as a cooling medium to the first reaction unit to suppress the rise in reaction temperature. The reaction rate in the first transesterification step may be around 65 to 95%.

[0068] In the first separation step, which follows the first transesterification step, the brine fraction is separated and removed, and the product fraction (oil layer) containing the product is sent to the next step. Methanol is further added to the product fraction. Preferably, the methanol added at this stage is pre-mixed with a catalyst solution. The product fraction and the added methanol are mixed in a static mixer and then introduced into the second reaction unit. The transesterification reaction continues as the mixture passes through the second reaction unit. The temperature of the second reaction unit may be around 45 to 55°C. In the second transesterification reaction, the reaction rate may be around 90 to 100%.

[0069] Preferably, the amount of methanol added in the first stage of the transesterification reaction in the second stage of the transesterification reaction in the second stage of the reaction unit is greater than the amount of methanol added in the first stage of the transesterification reaction in the first stage of the reaction unit. The ratio (by weight) of methanol added in the first and second stages may be approximately 5:1 to 2:1 for the first stage to the second stage.

[0070] The reaction mixture removed from the second reaction unit is introduced into the second separator, where a second separation step is performed to separate the product fraction from the brine fraction containing glycerin. The brine fraction is removed from the bottom of the second separator. The product fraction (oil layer) containing the product is removed through piping connected to the side of the second separator.

[0071] Water is added to the product fraction (oil layer) removed from the second separator, and washing is performed. Washing may be done once or multiple times. The product containing fatty acid methyl ester obtained after washing is stored in a tank. Subsequently, the obtained fatty acid methyl ester may be further purified by distillation or the like. The yield of fatty acid methyl ester is, for example, 90% or more, preferably 95% or more.

[0072] (Second Fatty Acid Methyl Ester Production Equipment) Figure 13 is a schematic diagram showing the configuration of a fatty acid methyl ester production equipment according to the present disclosure. The production equipment shown in Figure 13 is a second fatty acid methyl ester production equipment. Referring to Figure 13, the production equipment 101 is generally a system in which a first raw material tank 111 containing fatty acids and a second raw material tank 112 containing methanol are each connected to a reaction tower 120 via piping, and the fatty acid methyl ester produced by the reaction in the reaction tower 120 is taken out from the reaction tower 120 to a product tank 113.

[0073] A pipe 142, serving as the first raw material supply line, is connected to the top of the reaction tower 120 and connects to the first raw material tank 111. A pipe 152, serving as the second raw material supply line, is connected to the bottom of the reaction tower 120 and connects to the second raw material tank 112. A pipe 161, serving as the product removal line for the products generated by the reaction in the reaction tower 120, is connected to the bottom of the reaction tower 120. Details of the reaction tower 120 will be described later.

[0074] A pipe 141 is connected to a first raw material tank 111 containing fatty acids. Pipe 141 is connected to pipe 142 via a first heat exchanger 131 and a heater 132. Pipe 161 is connected to pipe 162 via a pump 138 and the first heat exchanger 131. In the first heat exchanger 131, heat exchange occurs between the raw material (fatty acid) flowing through pipe 141 and the product flowing through pipe 161. In the first heat exchanger 131, the temperature of the raw material flowing through pipe 141 rises, and the temperature of the product flowing through pipe 161 decreases. The raw material heated in the first heat exchanger 131 is further heated in a heater 132 equipped with a heater to become high-temperature (e.g., 260°C) liquid fatty acid. The high-temperature liquid fatty acid is supplied to the top of the reaction tower 120 through pipe 142.

[0075] A pipe 151 is connected to a second raw material tank 112 containing methanol. The pipe 151 passes through an evaporator 133 and a heater 134 before connecting to another pipe 152. The methanol vapor vaporized in the evaporator 133 is further heated in the heater 134 to become high-temperature methanol gas (e.g., 270°C). The high-temperature methanol gas is supplied to the lower part of the reaction tower 120 through the pipe 152.

[0076] High-temperature liquid fatty acids supplied from the top of the reaction tower 120 flow downward due to gravity. High-temperature gas methanol supplied from the bottom of the reaction tower 120 rises within the reaction tower 120. A dehydration reaction occurs when the flowing fatty acids and rising methanol come into contact, producing fatty acid methyl esters and water.

[0077] A reflux line, pipe 171, is connected to the top of the reaction column 120. Pipe 171 passes through the second heat exchanger 135 to the reflux drum 136. Pipe 172 connects to the reflux drum 136, and the mixture of reliquefied fatty acids, methanol, and water is refluxed back into the reaction column 120. Through pipe 173 connected to the reflux drum 136, a gas containing methanol and water is introduced into the distillation column 137. In the distillation column 137, methanol is separated by distillation. The methanol condensed in the distillation column 137 and the condenser 139 is supplied (recovered) through pipe 175 to the second raw material tank 112 which contains methanol.

[0078] The piping 151 passes through a second heat exchanger 135 before reaching the evaporator 133. In the second heat exchanger 135, heat exchange occurs between the raw material (methanol) flowing through piping 151 and the evaporated mixture flowing through piping 171. In the second heat exchanger 135, the temperature of the raw material flowing through piping 151 rises, and the temperature of the evaporated mixture flowing through piping 171 decreases. The raw material heated in the second heat exchanger 135 is further heated and vaporized in the evaporator 133. By placing the second heat exchanger 135 before the evaporator 133, thermal energy in the manufacturing equipment can be used effectively.

[0079] Figure 14 is a schematic diagram showing the configuration of a reaction tower in a fatty acid methyl ester production facility according to the present disclosure. The reaction tower 120 is a bubble tower with a large number of stages. The number of stages can be selected according to the target substance and preferred reaction conditions, and can be 40 to 55 stages. More specifically, a reaction tower 120 consisting of 49 stages can efficiently produce fatty acid methyl esters, and fatty acid methyl esters can be obtained in high yield even in a catalyst-free reaction.

[0080] Referring to Figure 14, the reaction tower 120 is a tray-type reaction tower with multiple trays inside. Each tray is connected by a downcomer, and liquid flows from top to bottom. The reaction tower 120 consists of multiple tray units stacked vertically. Each tray unit has multiple (e.g., four) trays. The configuration of the tray units is not limited and may include one to five trays.

[0081] Figure 15 is a schematic diagram showing the interior of a reaction tower of the manufacturing equipment according to this disclosure. The reaction tower 120 comprises a plurality of outer tanks 121a and 121b stacked vertically. Each of the outer tanks 121a and 121b constitutes a reaction stage. The even-numbered stages and odd-numbered stages of the reaction tower have similar configurations, and the even-numbered and odd-numbered stages are point-symmetrical. The dimensions of each outer tank (one reaction stage) may be 30 to 45 cm in height and 50 to 70 cm in diameter. When within this range, fatty acid esters can be produced efficiently in high yield.

[0082] Referring to Figure 15, the outer tanks 121a and 121b each constitute a reaction stage with a height of 40 cm and a diameter of 65 cm. The outer tank 121a comprises a first cylinder 122a rising from the bottom surface 125a of the outer tank 121a, and a second cylinder 123a that is shorter in height than the first cylinder 122a and also rises from the bottom surface 125a. Furthermore, inside the first cylinder 122a is a third cylinder 124a that penetrates the bottom surface 125a, with a portion protruding above the bottom surface and a portion protruding below the bottom surface. The first cylinder 122a is 38 cm high and 13 cm in diameter, and is a cylinder that rises to almost the full height of the outer tank 121a. The second cylinder 123a is 30 cm high and 13 cm in diameter, and is about 3 / 4 the height of the outer tank 121a. The third cylinder 124a is positioned to protrude 25 cm above the bottom surface 125a and 37 cm below the bottom surface 25a. The lower side of the third cylinder 124a is positioned to be inserted into the second cylinder 123b, which is one level below it. In other words, the third cylinder 124a is positioned from inside the first cylinder 122a to inside the second cylinder 123b, which is one level below it.

[0083] The first cylinder 122a and the second cylinder 123a are positioned diagonally opposite each other near the periphery of the outer tank 121a. Multiple bubble bells 211a are provided between the first cylinder 122a and the second cylinder 123a.

[0084] The outer tank 121b, which is the reaction stage one level below the outer tank 121a, has the same configuration as the outer tank 121a. Inside the outer tank 121b, there is a first cylinder 122b rising from the bottom surface 125b and a second cylinder 123b rising from the bottom surface 125b. Furthermore, inside the first cylinder 122b, there is a third cylinder 124b that penetrates the bottom surface 125b, with a portion protruding above the bottom surface and a portion protruding below the bottom surface. The shapes of the first cylinder 122b, the second cylinder 123b, and the third cylinder 124b are the same as those provided in the outer tank 121a. Multiple bubble bells 211b are provided between the first cylinder 122b and the second cylinder 123b.

[0085] A downcomer is formed by the first cylinders 122a and 122b, the second cylinders 123a and 123b, and the third cylinders 124a and 124b. The height of the first cylinders 122a and 122b is greater than the protruding height of the third cylinders 124a and 124b, and extends to almost the full height of the outer tanks 121a and 121b. This ensures sufficient contact time between the flowing liquid fatty acids and the rising methanol gas, does not obstruct the movement of methanol gas, and suppresses droplet entrainment.

[0086] The first cylinders 122a and 122b have notches 221a and 221b formed in the peripheral walls of the rising portions from the bottom surfaces 125a and 125b. The notches 221a and 221b are formed on the outer circumference of the peripheral wall, far from the center of the outer tank. The notches 221a and 221b are approximately 30 mm high and 80 mm wide. Liquid fatty acids flow into and out of the first cylinders 122a and 122b through the notches 221a and 221b. By providing the notches 221a and 221b on the outer circumference of the peripheral wall, far from the first cylinders 122a and 122b and the bubble bell 211, the liquid does not short-circuit, and the residence time of the liquid can be ensured. The first cylinders 122a and 122b act as sheaths for the third cylinders 124a and 124b, which prevents unreacted liquid from flowing down even if bumping occurs.

[0087] The second cylinders 123a and 123b have notched holes 231a and 231b formed in the peripheral walls of the rising portions from the bottom surfaces 125a and 125b. The notched holes 231a and 231b are semicircular holes with a radius of approximately 4 mm. Liquid fatty acids flow out from inside the second cylinders 23a and 23b through these notched holes 231a and 231b. By providing the notched holes 231a and 231b on the outer circumference side of the peripheral wall (closer to the outer tank), which is far from the first cylinders 122a and 122b and the bubble bell 211, the liquid does not short-circuit and the liquid residence time can be ensured.

[0088] The bubble bell body 211 consists of a cap with multiple elongated holes at its lower end and an inner cylinder housed inside the cap. The inner cylinder penetrates the bottom surface of the tray and is approximately half the height of the cap.

[0089] Figure 16 is a schematic diagram showing the interior of the reaction tower of the manufacturing equipment according to this disclosure. Figure 16 is a horizontal cross-section of the tray 121, and is a view taken along the line XVI-XVI in Figure 15. The third cylinder 124 is positioned inside the first cylinder 122. The first cylinder 122 and the second cylinder 123 are positioned diagonally opposite each other. Sixteen bubble bells 211 are positioned between the first cylinder 122 and the third cylinder 124. In even-numbered and odd-numbered stages, the first cylinder 122 and the second cylinder 123 are positioned in opposite positions. The number of bubble bells provided in the tray 121 can be set considering the reaction efficiency, etc., and is not particularly limited, but it is preferably 10 to 24.

[0090] In the reaction tower 120, liquid fatty acids flow down from the top through a downcomer, and methanol gas rises from the bottom through a bubble bell. Fatty acid methyl esters and water are produced as the liquid fatty acids and methanol gas come into contact at each stage. The amount of water in the methanol gas increases towards the top of the reaction tower, and the amount of fatty acid methyl esters in the liquid increases towards the bottom of the reaction tower. The methanol gas dissolves in the liquid and functions as a reaction raw material, and as an rising gas, it also stirs the reaction mixture.

[0091] (Manufacturing Method) The method for producing fatty acid methyl esters according to this disclosure is preferably carried out in the manufacturing equipment described above. The manufacturing method according to this disclosure will be described with reference to Figure 13.

[0092] The method for producing fatty acid methyl esters includes an esterification step. In the esterification step, fatty acids are introduced from a first raw material tank 111 to the upper part of the reaction tower 120, and methanol is introduced from a second raw material tank 112 to the lower part of the reaction tower 120, and the fatty acids and methanol are brought into contact within the reaction tower 120. The fatty acids introduced into the reaction tower 120 are heated in a first heat exchanger 131 by heat exchange with the reactants (the product, fatty acid methyl esters) flowing through the piping 161 that is discharged from the reaction tower 120. The fatty acids introduced into the reaction tower 120 are further heated in a heater 132 and introduced into the reaction tower 120 at a temperature of approximately 260°C. The flow rate of the fatty acids is set according to the production volume, etc., but can be set to, for example, 800 to 1600 kg / h.

[0093] The methanol introduced into the reaction tower 120 is heated in the second heat exchanger 135 by heat exchange with the reflux product discharged from the reaction tower 120. The methanol introduced into the reaction tower 120 is vaporized in the evaporator 133 and further heated in the heater 134, and introduced into the reaction tower 120 at a temperature of approximately 270°C. The methanol flow rate is set according to the production volume, etc., but can be set to, for example, 230 to 480 kg / h. The ratio of methanol to fatty acid charged can be set to approximately 2.1 mol / 1 mol when the fatty acid is oleic acid. The ratio of the amount of fatty acid charged to the amount of methanol charged per unit time may be 1:1.8 to 1:3.0 (molar ratio), and 1:1.9 to 1:2.7 (molar ratio) is preferred. The amounts of fatty acid and methanol charged may be changed according to the overall situation of the manufacturing process. For example, if the acid value of the obtained fatty acid methyl ester is judged to be high, the methanol flow rate may be kept constant, and the relative supply of oleic acid may be reduced to about 80% of the amount used in a normal reaction. Also, during idling operation of the manufacturing equipment (a state in which the fatty acid methyl ester is not recovered and the raw materials are refluxed within the manufacturing equipment), the methanol flow rate may be kept constant, and the relative supply of oleic acid may be reduced to about 50% of the amount used in a normal reaction.

[0094] The inside of the reaction tower 120 may be under pressure, and can be set to, for example, about 0.87 MPa.

[0095] The esterification reaction may be carried out without a catalyst, or a catalyst may be used to improve the reaction rate. When a catalyst is used, iron catalysts, titanium catalysts such as tetra-n-butoxytitanium or titanium diisopropoxybis(triethanolamine), and tin catalysts such as dibutyltin oxide or di(2-ethylhexanoate)tin(II) can be used. For example, when using an iron catalyst, iron powder may be added to the fatty acid contained in the first raw material tank 111 as a catalyst addition step. From the viewpoint of catalyst separation from the product and avoiding clogging of the reaction equipment caused by solid catalysts, it is preferable to carry out the esterification reaction without a catalyst.

[0096] The fatty acids used in the production of fatty acid methyl esters may be animal-derived fatty acids or plant-derived fatty acids. It is preferable that the fatty acids include unsaturated fatty acids. The unsaturated fatty acids may be a mixture of oleic acid, linoleic acid, alpha-linolenic acid, gamma-linolenic acid, arachidonic acid, etc., and it is preferable that the fatty acids contain oleic acid as the main component. Here, "main component" means the component that makes up the largest amount of the fatty acids contained.

[0097] Using the manufacturing equipment described herein, fatty acid methyl esters can be obtained in high yield. The manufacturing process may be a continuous reaction. As an example, oleic acid was introduced into a reaction column at a flow rate of 1068 kg / h and methanol at a flow rate of 277 kg / h, and esterification was performed, resulting in the acquisition of fatty acid methyl esters with a yield of over 99%. The excess methanol refluxed and recovered from the top of the reaction column 120 was recovered in the distillation column 137, stored in the second raw material tank 112, and then reused as a raw material. The acid value of the product was 3.7 mg KOH / g. The manufacturing equipment described herein can stably produce fatty acid methyl esters with a sufficiently reduced acid value (specifically, an acid value of 7 mg KOH / g or less).

[0098] (Unsaturated Alcohol Production Equipment) The unsaturated alcohol production equipment according to this disclosure includes a first fatty acid methyl ester production equipment equipped with a tubular reactor, a second fatty acid methyl ester production equipment equipped with a bubble tower having a plurality of reaction stages, and a reduction reaction equipment for obtaining an unsaturated alcohol by contacting a fatty acid methyl ester with hydrogen. The above-described production equipment 1 is preferred as the first fatty acid methyl ester production equipment. The above-described production equipment 101 is preferred as the second fatty acid methyl ester production equipment.

[0099] The reduction reaction apparatus can be the apparatus disclosed in Japanese Patent Publication No. 2025-143923. The reduction reaction apparatus may be an apparatus comprising a plurality of reaction towers filled with granular solid catalyst and connected in series with each other. The plurality of reaction towers are connected to each other via piping in a repeating manner, with one reaction tower in which fatty acid methyl ester, aliphatic alcohol, and hydrogen gas flow downward in parallel, and the other reaction tower in which fatty acid alkyl ester, aliphatic alcohol, and hydrogen gas flow upward in parallel. The raw materials, unsaturated fatty acid methyl ester and hydrogen gas, are introduced into the reaction towers from one end of the reaction towers connected in series with each other.

[0100] The reduction reaction equipment may or may not be connected to the first fatty acid methyl ester production equipment and the second fatty acid methyl ester production equipment via piping. If not connected, the product tank connected to the fatty acid methyl ester production equipment may be configured to be detachable, and the fatty acid methyl ester product tank may be used as the raw material tank for the reduction reaction equipment. Alternatively, the fatty acid methyl ester produced in the fatty acid methyl ester production equipment may be filled into drums or the like, transported to the reduction reaction equipment, and fed into the raw material tank of the reduction reaction equipment.

[0101] In the first fatty acid methyl ester production facility, unsaturated fatty acid methyl esters can be produced using oils and fats as raw materials. In the second fatty acid methyl ester production facility, unsaturated fatty acid methyl esters can be produced using fatty acids as raw materials. The unsaturated fatty acid methyl esters obtained in these ways can be mixed as needed, and unsaturated alcohols can be produced by reducing the methyl esters to alcohols in a reduction reaction facility.

[0102] The embodiments disclosed herein should be understood to be illustrative in all respects and not restrictive in any way. The scope of the present invention is defined by the claims and is intended to include all modifications in the sense and scope equivalent to the claims.

[0103] 1 Manufacturing equipment, 7 racks, 10 first reaction unit, 11 straight tube, 12 first static mixer, 13 first curved tube, 14 second curved tube, 15 first separator, 16 inlet, 17 outlet, 18 single tube, 19 double tube, 20 second reaction unit, 22 second static mixer, 25 second separator, 31 raw material oil tank, 32, 22 methanol tank, 41 raw material introduction piping, 42, 43, 44, 45 piping, 50 purification section, 51 initial distillation column, 52 main distillation column, 53 concentration column, 71 base, 72 support column, 83 central pipe section, 84 jacket, 85 heat transfer medium inlet, 86 heat transfer medium outlet, 88, 89 flange, 101 manufacturing equipment, 111 first raw material tank, 112 second raw material tank, 113 product tank, 120 Reaction column, 121; Trays, 121a, 121b; Outer tank, 122 (122a, 122b); First cylinder, 123 (123a, 123b); Second cylinder, 124 (124a, 124b); Third cylinder, 125a, 125b; Bottom, 211 (211a, 211b); Bubble bell, 221 (221a, 221b), 231 (231a, 231b); Notch hole, 131; First heat exchanger, 132, 134; Heater, 133; Evaporator, 135; Second heat exchanger, 136; Reflux drum, 137; Distillation column, 138; Pump, 139; Condenser, 141, 142, 151, 152, 161, 162, 171, 172, 173, 175 Piping.

Claims

1. An unsaturated alcohol production apparatus comprising: a first fatty acid methyl ester production apparatus equipped with a tubular reactor; a second fatty acid methyl ester production apparatus equipped with a bubble tower having multiple reaction stages; and a reduction reaction apparatus for obtaining an unsaturated alcohol by contacting a fatty acid methyl ester with hydrogen.

2. A production apparatus for fatty acid methyl esters comprising: a first static mixer connected to a raw material introduction pipe; a first reaction unit connected downstream of the first static mixer; a first separator connected downstream of the first reaction unit; a second static mixer connected downstream of the first separator; a second reaction unit connected downstream of the second static mixer; and a second separator connected downstream of the second reaction unit, wherein each of the first and second reaction units is a tubular reactor satisfying that the reaction section piping length (L) relative to the pipe diameter (p) is L ≥ p × 8,000; the tubular reactor consists of a plurality of straight pipes and a plurality of curved pipes connecting the straight pipes, the curved pipes include a first curved pipe and a second curved pipe having a smaller curvature radius than the first curved pipe, all of the plurality of straight pipes and the first curved pipe are arranged horizontally, and the second curved pipe is arranged horizontally and vertically.

3. The fatty acid methyl ester production apparatus according to claim 2, wherein the plurality of straight pipes are of the same length and are arranged to form a plurality of stages spaced equally apart in the vertical direction, and the uppermost stage and the straight pipes belonging to each of the uppermost stages are all connected by the first curved pipe.

4. The production apparatus for fatty acid methyl ester according to claim 2, wherein the plurality of straight tubes include single-walled straight tubes and double-walled straight tubes equipped with jackets through which a heat transfer medium flows, and the plurality of stages include stages composed of single-walled straight tubes and stages composed of double-walled straight tubes.

5. The fatty acid methyl ester production apparatus according to claim 3, wherein the plurality of stages number 5 to 11, and of the plurality of stages, the uppermost stage, the lowermost stage, and at least one stage between the uppermost stage and the lowermost stage are stages made of double tubes.

6. The fatty acid methyl ester production apparatus according to claim 3, wherein the number of stages in the plurality of stages is 11, and the top stage, the fourth stage and the seventh stage are stages composed of the double tube.

7. The production apparatus for fatty acid methyl esters according to claim 2 or 3, wherein each of the first reaction unit and the second reaction unit comprises 96 of the straight tubes.

8. A method for producing a fatty acid methyl ester in a fatty acid methyl ester production facility according to claim 2 or claim 3, comprising: a first transesterification step of introducing raw material oil and methanol into the first reaction unit through the raw material introduction pipe and performing transesterification; a first separation step following the first transesterification step of separating a product fraction and a glycerin-containing hydrate fraction in the first separator; a second transesterification step following the first separation step of further adding methanol to the product fraction, introducing it into the second reaction unit and performing transesterification; and a second separation step following the second transesterification step of separating a product fraction and a glycerin-containing hydrate fraction in the second separator.

9. The method for producing a fatty acid methyl ester according to claim 8, wherein the amount of methanol added in the first transesterification step is 2 times the theoretical reaction amount in moles or more, and the amount of methanol added in the second transesterification step is 1 to 1.1 times the theoretical reaction amount in moles.

10. A production apparatus for fatty acid methyl esters, comprising: a first raw material tank for containing fatty acids; a second raw material tank for containing methanol; a reaction tower with a first raw material supply line connected to the first raw material tank at the top and a second raw material supply line connected to the second raw material tank at the bottom; and a removal line for removing the product from the reaction tower, wherein the reaction tower is a bubble tower having 40 to 55 reaction stages, and is equipped with a first heat exchanger for heat exchange between the first raw material supply line and the removal line.

11. The production apparatus for fatty acid methyl esters according to claim 10, wherein the bubble tower is made up of vertically stacked reaction stages having a height of 30 to 45 cm and a diameter of 50 to 70 cm, each of the reaction stages comprising: a first cylinder rising from the bottom surface of the reaction stage; a second cylinder rising from the bottom surface of the reaction stage and being shorter in height than the first cylinder; and a third cylinder positioned inside the first cylinder, penetrating the bottom surface of the reaction stage and having a portion that protrudes upward from the bottom surface and a portion that protrudes downward from the bottom surface, the third cylinder being installed to be inserted into the second cylinder of the reaction stage one level below.

12. The production apparatus for fatty acid methyl esters according to claim 11, wherein each of the first cylinder and the second cylinder has a notched hole formed in the peripheral wall of the rising portion from the bottom surface of the reaction stage.

13. The apparatus for producing fatty acid methyl esters according to claim 10 or claim 11, wherein each of the reaction stages comprises 10 to 24 foam bells.

14. A method for producing a fatty acid methyl ester in a fatty acid methyl ester production facility according to claim 10 or claim 11, comprising an esterification step of introducing a fatty acid from a first raw material tank into the reaction tower and introducing methanol from a second raw material tank into the reaction tower, and bringing the fatty acid and methanol into contact in the reaction tower, wherein, in the first heat exchanger, after the esterification step, heat exchange is performed between the reactant discharged from the reaction tower and flowing through the extraction line and the fatty acid discharged from the first raw material tank and flowing through the first raw material supply line.

15. A method for producing a fatty acid methyl ester according to claim 14, comprising the step of adding iron powder to the fatty acid contained in the first raw material tank.

16. The method for producing a fatty acid methyl ester according to claim 15, wherein, in the esterification step, the ratio of the amount of fatty acid charged to the reaction tower per unit time to the amount of methanol charged to the reaction tower is 1:1.8 to 1:3.0 (molar ratio).

Images