Equipment for manufacturing fatty acid methyl esters and method for manufacturing fatty acid methyl esters

Abstract

To provide a manufacturing facility that suppresses the generation of by-products and can stably produce fatty acid methyl esters on an industrial scale, and a method for producing fatty acid methyl esters using such a facility. [Solution] A manufacturing facility comprising a first static mixer connected to a raw material introduction pipe, a first reaction unit connected downstream thereof, a first separator connected downstream thereto, a second static mixer connected downstream thereto, a second reaction unit connected downstream thereto, and a second separator connected downstream thereto. 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, and 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. The plurality of straight pipes and the first curved pipe are arranged horizontally, and the second curved pipe is arranged horizontally and vertically.

Description

Technical Field

[0001] The present invention relates to a production facility for fatty acid methyl ester and a method for producing fatty acid methyl ester.

Background Art

[0002] As a method for producing 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 the alkali component, sodium hydroxide or potassium hydroxide is used. For example, Patent Document 1 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.

[0003] Patent Document 2 discloses that as a production apparatus for fatty acid methyl ester, the transesterification region is constituted by a static mixer. As a specific configuration of the transesterification region, 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 2 discloses that by generating turbulent flow in the transesterification region, the reaction raw materials can quickly reach the reaction equilibrium.

[0004] Patent Document 3 discloses, as a method for producing fatty acid methyl ester, a step of reacting fats and oils, methanol, and calcium hydroxide or calcium oxide, and using the amount of methanol in the reaction step such that the reaction mixture after the reaction step separates into two layers, the main component of the upper layer is methanol, and the upper layer becomes transparent. According to the production method of Patent Document 3, it is disclosed that by using methanol at 10 times or more the stoichiometric amount of the reaction, the amount of calcium component remaining in the obtained fatty acid methyl ester can be sufficiently reduced.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 50-62926 [Patent Document 2] Special Publication No. 2001-524553 [Patent Document 3] Japanese Patent Publication No. 2009-67904 [Overview of the project] [Problems that the invention aims to solve]

[0006] 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. [Means for solving the problem]

[0007] The manufacturing 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 and second reaction units 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 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. [Effects of the Invention]

[0008] The manufacturing equipment described herein can suppress the generation of by-products and produce fatty acid methyl esters stably and in an industrial scale. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing the configuration of the manufacturing equipment related to this disclosure. [Figure 2] Figure 2 is a front view showing the first reaction unit of the manufacturing equipment according to this disclosure. [Figure 3] Figure 3 is a side view showing the first reaction unit of the manufacturing equipment according to this disclosure. [Figure 4] Figure 4 is a side view showing the first reaction unit of the manufacturing equipment according to this disclosure. [Figure 5] 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] 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] 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] 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] 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] 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] Figure 11 is a cross-sectional view showing the configuration of a straight tube in the reaction unit of the manufacturing equipment according to this disclosure. [Figure 12] Figure 12 is a cross-sectional view showing the configuration of a straight tube in the reaction unit of the manufacturing equipment according to this disclosure. [Modes for carrying out the invention]

[0010] [Summary of the Embodiment] First, embodiments of the manufacturing equipment and manufacturing method for fatty acid methyl esters according to this disclosure will be listed and described. In this specification, unless otherwise specified, "A to B" representing a numerical range means "greater than or equal to A and less than or equal to B".

[0011] The manufacturing 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 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 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.

[0012] For example, as disclosed in Patent Document 2, as a means for generating turbulent flow to promote the mixing of raw material oil and fat and methanol in the production of fatty acid methyl ester, a reaction apparatus equipped with a large number of balls or baffle plates in a reaction tube has been proposed. However, from the viewpoints of maintainability, reaction efficiency, cost, etc., the need for an apparatus for industrially and stably performing the transesterification reaction continues. Under this situation, studies on reaction apparatuses have been conducted, and it has been found that by adopting a tubular reactor and further setting the configuration of the tubes of the tubular reactor to the above-described configuration, long piping can be accommodated in a limited space, the generation of by-products can be suppressed, and fatty acid methyl ester can be stably produced on an industrial scale. The production facility according to the present disclosure has a configuration in which the length of the reaction tube is large with respect to the diameter of the reaction tube, and a plurality of straight tubes are connected via curved tubes. It is considered that the production facility according to the present disclosure has a long reaction tube and a plurality of curved portions, thereby ensuring mixing performance and enabling efficient and stable transesterification.

[0013] In the production facility, the plurality of straight tubes may have the same length as each other and may be arranged so as to form a plurality of stages spaced at equal intervals in the vertical direction. The straight tubes belonging to the uppermost stage and the lowermost stage among the plurality of stages may all be connected by the first curved tube. According to this configuration, the reaction raw materials flowing through the piping can be stably and surely mixed, temperature adjustment can be performed, and the transesterification reaction can be advanced.

[0014] In the production facility, the plurality of straight tubes may include a straight tube that is a single tube and a straight tube that is a double tube provided with a temperature control jacket through which a heat medium flows. The plurality of stages may include a stage composed of the straight tubes that are single tubes and a stage composed of the straight tubes that are double tubes. According to this configuration, it is possible to appropriately warm the reaction raw materials flowing through the piping, and it is possible to provide a facility that is easy to maintain and suitable for industrial operation.

[0015] In the manufacturing equipment, the plurality of stages may be 5 to 11 stages, and among the plurality of stages, the uppermost stage, the lowermost stage, and at least one or more stages between the uppermost stage and the lowermost stage may be stages constituted by the double pipes. Further, in the manufacturing equipment, the plurality of stages may be 11 stages, and the uppermost stage, the fourth stage, and the seventh stage may be stages constituted by the double pipes. By separating the stages having a temperature adjustment function from the other stages among the plurality of stages and arranging the stages having a temperature adjustment function at substantially equal intervals, temperature management can be more appropriately implemented.

[0016] In the manufacturing equipment, each of the first reaction unit and the second reaction unit may be a device including 96 of the straight pipes. By adopting such a piping configuration, a necessary and sufficient transesterification reaction can occur, and fatty acid methyl ester can be produced with good yield.

[0017] The method for producing fatty acid methyl ester according to the present disclosure is a method for producing fatty acid methyl ester in the above-described manufacturing equipment for fatty acid methyl ester. The production method includes a first transesterification step of introducing raw material oil and fat and methanol into the first reaction unit through the raw material introduction pipe and performing transesterification, a first separation step of separating a product fraction and a glycerin-containing aqueous fraction in the first separator following the first transesterification step, a second transesterification step of further adding methanol to the product fraction, introducing it into the second reaction unit, and performing transesterification following the first separation step, and a second separation step of separating a product fraction and a glycerin-containing aqueous fraction in the second separator following the second transesterification step. According to this production method, a sufficient transesterification reaction can occur under mild reaction conditions, and fatty acid methyl ester can be produced with good yield.

[0018] 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.

[0019] 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 manufactured in good yield.

[0020] [Specific examples of embodiments] Next, an example of a specific embodiment of the manufacturing equipment and manufacturing method relating 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. In the following description, "upper" and "lower" mean relatively above or below along the vertical direction.

[0021] (manufacturing equipment) Figure 1 is a schematic diagram showing the configuration of a fatty acid methyl ester manufacturing facility according to this disclosure. Referring to Figure 1, the manufacturing facility 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 manufacturing facility 1 is a two-stage reaction facility 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.

[0022] 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 unit 50.

[0023] 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.

[0024] The raw material introduction piping 41 is connected to the raw material oil tank 31 and the methanol tank 32. Although not shown in the diagram, an alkali inlet is also provided for introducing the alkali catalyst. The raw material oil, methanol, and alkali are introduced into the first static mixer 12 through the raw material introduction piping 41. In the first static mixer 12, the reaction materials are stirred and mixed, and introduced into the first reaction unit 10 as turbulent flow. Transesterification occurs as the reaction materials pass through the first reaction unit 10.

[0025] From the reaction mixture exiting the first reaction unit 10, the brine is separated in the first separator 15. The brine contains glycerin produced by the transesterification reaction and a water-soluble alkaline catalyst. The product fraction removed from the first separator 15 is taken out through piping 43. The product fraction contains unreacted raw material oils and the produced fatty acid methyl esters. A methanol tank 33 is connected to piping 43 and is mixed with the product fraction removed from the first separator 15, stirred and mixed in the second static mixer 22, and introduced into the second reaction unit 20. The reaction materials undergo further transesterification as they pass through the second reaction unit 20. The first separator 15 is an oil-water separator, and the brine can be taken out through a line connected to the bottom. Piping 42, which is an introduction line, and piping 43, which is an extraction line, are connected to the side of the tank portion of the first separator 15.

[0026] The reaction mixture taken from the second reaction unit 20 through piping 44 is introduced into the purification section 50 after the brine is separated again in the second separator 25. The second separator 25 is an oil-water separator having the same configuration as the first separator 15. As described above, the purification section 50 includes an initial distillation column 51, a main distillation column 52, and a concentration column 53, and preferably also includes an atmospheric pressure purification device and a vacuum purification device (not shown). In the purification section 50, it is preferable that water and methanol, which are low-boiling point components, are first removed by distillation in the atmospheric pressure purification device and the vacuum purification device. Subsequently, chlorine-containing oxides, which are low-boiling point components, are removed in the initial distillation column 51. It is preferable that chlorine-containing oxides are reliably removed in the initial distillation column 51, as the presence of chlorine-containing oxides in fatty acid methyl esters may inhibit further reactions using fatty acid methyl esters as raw materials.

[0027] In the main distillation column 52, fatty acid methyl esters are extracted as distillation components. The fraction from the main distillation column 52 is introduced into the concentration column 53 and heated again, separating high-boiling-point components such as oil polymers and soap components, which are then discharged as pitch. Meanwhile, the fatty acid methyl ester components mixed in the fraction are introduced back into the main distillation column 52 from the concentration column 53.

[0028] The first reaction unit 10 and the second reaction unit 20 will now be described. Both the first reaction unit 10 and the second reaction unit 20 are tubular reactors with numerous long pipes arranged in multiple stages. The first reaction unit 10 and the second reaction unit differ in the length of their reaction pathways. Figure 2 is a schematic front view of the first reaction unit 10. Figure 3 is a schematic side view of the first reaction unit 10, taken along the line III-III in Figure 2. Figure 4 is a schematic side view of the first reaction unit 10, taken along the line IV-IV in Figure 2.

[0029] 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 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. Figures 3 and 4 show only the frame of the rack 7, and details are omitted.

[0030] 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.

[0031] 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" means that the flow path extends horizontally. On the other hand, the second curved pipes 14 are arranged both horizontally and 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.

[0032] 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 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 first reaction unit 10 as a whole is equipped with 62 straight pipes 11.

[0033] 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.

[0034] 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 3 is a view taken along the line VI-VI in Figure 5. Figure 7 is a view taken along the line VII-VII in Figure 5.

[0035] 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 multiple 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.

[0036] 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.

[0037] 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 arrow IX-IX in Figure 8. Figure 10 is a view taken along the arrow XX 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 support columns 72, is the same as described above. The lower section 20B is stacked in five stages at equal intervals. The lower section 20B includes multiple 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.

[0038] 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), fourth section, and fifth section, the straight pipes 11 are connected by the first curved pipe 13. In the second section and 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 section, and fifth section. There are eleven straight pipes in each of the second section and third section. 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.

[0039] 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 108 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 109 at both ends and comprises a central pipe section 103 through which reaction materials flow, and a jacket 104 surrounding the central pipe section 103 through which a heat transfer medium flows. The jacket 104 has a heat transfer medium inlet 105 and a heat transfer medium outlet 106 at both ends in the longitudinal direction. The heat transfer medium is not particularly limited; for example, water can be used as a cooling medium when lowering the temperature of the reaction materials in the reaction unit. Steam can be used as a heating medium when raising the temperature of the reaction materials in the reaction unit.

[0040] 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. In the lower section 20B of the second reaction unit 20, as shown in Figures 8 to 10, the uppermost, fourth, and lowermost straight tubes 11 are double-walled tubes 19. The second and third straight tubes 11 are single-walled tubes 18. This configuration allows for more efficient heat exchange and reliable temperature control of the reactants.

[0041] 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 of approximately 25A to 60A diameter and 2000mm to 6000mm in length, and can be appropriately selected according to the scale and purpose of the equipment.

[0042] (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.

[0043] 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.

[0044] 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 state where it is dissolved in methanol. For example, a NaOH / 10% methanol solution can be used as the catalyst solution.

[0045] (manufacturing process) 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 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 the product fraction and a glycerin-containing hydrate fraction in a second separator.

[0046] The raw material oils to be used in the first transesterification process may be preheated in a preheater. The preheating temperature may be around 50-60°C. Methanol and a catalyst solution are added to the preheated raw material oils and mixed in a static mixer. As an example, the raw materials can be continuously supplied to the first transesterification process by supplying 3500 kg / h of raw material oils, 715 kg / h of methanol, and 108 kg / h of the NaOH / 10% methanol catalyst solution. If the average molecular weight of 3500 kg of raw material oils is approximately 870 and the molecular weight of methanol is 32, the supply rate of raw material oils 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.

[0047] 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 45-55°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 65-95%.

[0048] 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 45-55°C. In the second transesterification reaction, the reaction rate may be around 90-100%.

[0049] Preferably, the amount of methanol added in the first stage of the transesterification reaction in the first reaction unit is greater than the amount of methanol added in the second stage of the transesterification reaction in the second 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 and the second stage.

[0050] 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.

[0051] Water is added to the product fraction (oil layer) removed from the second separator, and washing is performed. Washing may be performed 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.

[0052] 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. [Explanation of Symbols]

[0053] 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, 103 central pipe section, 104 jacket, 105 heat transfer medium inlet, 106 heat transfer medium outlet, 108, 109 flanges.

Claims

1. The first static mixer connected to the raw material introduction piping, 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, A second separator connected downstream of the second reaction unit, Equipped with, Each of the first and second reaction units is a tubular reactor in which the reaction section piping length (L) relative to the pipe diameter (p) satisfies L ≥ p × 8,000. The aforementioned tubular reactor consists of a plurality of straight tubes and curved tubes connecting the straight tubes. The curved tube includes a first curved tube and a second curved tube having a curvature radius smaller than that of the first curved tube. All of the aforementioned straight pipes and the first curved pipe are arranged horizontally. The second curved pipe is arranged in the horizontal and vertical directions. Manufacturing equipment for fatty acid methyl esters.

2. The aforementioned multiple straight pipes are of the same length and are arranged to form multiple stages that are equally spaced in the vertical direction. The uppermost of the multiple stages and the straight pipes belonging to each of the uppermost stages are all connected by the first curved pipe. The production apparatus for fatty acid methyl esters according to claim 1.

3. The plurality of straight pipes include single-walled straight pipes and double-walled straight pipes equipped with a jacket through which a heat transfer medium flows. The aforementioned plurality of stages include stages composed of single-walled straight pipes and stages composed of double-walled straight pipes. The production apparatus for fatty acid methyl esters according to claim 2.

4. The aforementioned multiple stages consist of 5 to 11 stages. Of the aforementioned multiple 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 pipes. The production apparatus for fatty acid methyl esters according to claim 3.

5. The aforementioned set of stages consists of 11 stages, with the top stage, the fourth stage, and the seventh stage being stages composed of the double-walled pipe. The production apparatus for fatty acid methyl esters according to claim 3.

6. Each of the first reaction unit and the second reaction unit is equipped with 96 of the straight tubes. A production apparatus for fatty acid methyl esters according to claim 1 or claim 2.

7. A method for producing fatty acid methyl esters in a fatty acid methyl ester production facility according to claim 1 or claim 2, A first transesterification step is performed by introducing raw material oil and methanol into the first reaction unit through the raw material introduction piping and transesterifying the oil and methanol. Following the first transesterification step, a first separation step is performed in the first separator to separate the product fraction from the sweet water fraction containing glycerin, Following the first separation step, methanol is further added to the product fraction and introduced into the second reaction unit for transesterification in a second transesterification step, Following the second transesterification step, a second separation step is performed in the second separator to separate the product fraction from the brine fraction containing glycerin, including, A method for producing fatty acid methyl esters.

8. The amount of methanol added in the first transesterification step is at least twice the theoretical reaction amount in moles. The amount of methanol added in the second transesterification step is 1 to 1.1 times the theoretical reaction amount in moles. A method for producing fatty acid methyl esters according to claim 7.

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