Equipment for producing unsaturated alcohol and method for producing unsaturated alcohol

Abstract

This production equipment comprises a reaction section including a first reaction tower, a second reaction tower, a third reaction tower, and a fourth reaction tower that are connected to each other in the stated order. The first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower are each filled with a granular solid catalyst. Raw material supply piping and hydrogen gas supply piping are connected to the upper part of the first reaction tower. The first reaction tower and the second reaction tower are connected via first connection piping that connects the lower end of the first reaction tower and the lower end of the second reaction tower, the second reaction tower and the third reaction tower are connected via second connection piping that connects the upper end of the second reaction tower and the upper end of the third reaction tower, and the third reaction tower and the fourth reaction tower are connected via third connection piping that connects the lower end of the third reaction tower and the lower end of the fourth reaction tower. An unsaturated alcohol is produced by this production equipment.

Description

Unsaturated alcohol production equipment and method for producing unsaturated alcohol

[0001] The present invention relates to an unsaturated alcohol production system and a method for producing an unsaturated alcohol. This application claims priority to Japanese Patent Application Nos. 2024-043438 and 2024-043439, filed on March 19, 2024, and the entire contents of these Japanese Patent Applications are incorporated herein by reference.

[0002] Known unsaturated alcohol production facilities include multiple reaction towers filled with solid catalysts. Patent Document 1 discloses hydrogenation by allowing "hydrogen gas" and a "liquid phase containing unsaturated fatty acid alkyl esters" to flow in parallel from the tops of multiple reaction towers filled with solid catalysts. The hydrogenation method disclosed in Patent Document 1 is characterized by controlling the amount of liquid phase held by the solid catalyst filled in the reaction towers, the strength of the solid catalyst, and the total amount of chlorine atoms and sulfur atoms in the substance to be hydrogenated within specific ranges.

[0003] Patent Document 2 discloses a fixed-bed continuous reaction method for reducing unsaturated fatty acid alkyl esters under high temperature and pressure using a zinc-based catalyst containing 30 ppm or less copper. Patent Document 2 also discloses that when performing reduction using a fixed-bed continuous reaction, a shaped solid catalyst is packed into a reaction tower, activated, and then the reaction is carried out by, for example, flowing "unsaturated fatty acid alkyl esters as a substance to be reduced" and "hydrogen gas" in a downward or upward cocurrent manner. The examples shown in Patent Document 2 describe a reduction reaction using unsaturated fatty acid methyl esters obtained by methyl-esterifying 10 kg of unsaturated fatty acids derived from palm kernel oil as a raw material, in the presence of a zinc-based catalyst containing 5 ppm copper, under conditions of a reaction pressure of 20 MPa, a reaction temperature of 290°C, and a superficial velocity of raw material feed of 0.3 m / h.

[0004] WO2004 / 048297 publication WO2003 / 089393 publication

[0005] The present invention aims to provide an unsaturated alcohol production facility using an unsaturated fatty acid alkyl ester as a raw material, which is capable of controlling the reduction reaction to obtain unsaturated alcohol in a high yield and is capable of continuously producing unsaturated alcohol on an industrial scale, and a method for producing unsaturated alcohol.

[0006] The unsaturated alcohol production equipment according to the present disclosure comprises a reaction section including a first reaction tower, a second reaction tower, a third reaction tower, and a fourth reaction tower connected to each other in this order. The first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower are each filled with a granular solid catalyst. A raw material supply pipe and a hydrogen gas supply pipe are connected to the top of the first reaction tower. The first reaction tower and the second reaction tower are connected via a first connecting pipe that connects the lower end of the first reaction tower to the lower end of the second reaction tower. The second reaction tower and the third reaction tower are connected via a second connecting pipe that connects the upper end of the second reaction tower to the upper end of the third reaction tower. The third reaction tower and the fourth reaction tower are connected via a third connecting pipe that connects the lower end of the third reaction tower to the lower end of the fourth reaction tower.

[0007] The production method according to the present disclosure is a method for producing an unsaturated alcohol by reducing an unsaturated fatty acid alkyl ester in the presence of a catalyst. The production method includes the steps of "charging an unsaturated fatty acid alkyl ester (wherein the alkyl ester has 1 to 4 alkyl carbon atoms) and an aliphatic monoalcohol having 1 to 4 carbon atoms into a reaction column" and "supplying hydrogen to the reaction column and obtaining an unsaturated alcohol by a reduction reaction."

[0008] The production equipment according to the present disclosure can control the reduction reaction to obtain unsaturated alcohols in high yields, and provides equipment capable of continuously producing unsaturated alcohols on an industrial scale.The production method according to the present disclosure provides a method for continuously producing unsaturated alcohols, which can suppress the generation of by-products and is applicable on an industrial scale, in the production of unsaturated alcohols using unsaturated fatty acid alkyl esters as raw materials.

[0009] Fig. 1 is a schematic diagram showing the configuration of a production facility according to the present disclosure. Fig. 2 is a cross-sectional schematic diagram showing the configuration of a reaction tower of the production facility according to the present disclosure. Fig. 3 is a schematic diagram showing the shape of a catalyst and the flow of a reaction system in the production facility according to the present disclosure.

[0010] [Outline of the embodiment] First, embodiments of the unsaturated alcohol production equipment and production method according to the present disclosure will be listed and described. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more and B or less."

[0011] The production equipment according to the present disclosure is equipment for producing unsaturated alcohols by reducing unsaturated fatty acid alkyl esters in the presence of a catalyst. The unsaturated alcohol production equipment according to the present disclosure comprises a reaction section including a first reaction tower, a second reaction tower, a third reaction tower, and a fourth reaction tower connected to each other in this order. The first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower are each filled with a granular solid catalyst. A raw material supply pipe and a hydrogen gas supply pipe are connected to the top of the first reaction tower. The first reaction tower and the second reaction tower are connected via a first connecting pipe connecting the lower end of the first reaction tower to the lower end of the second reaction tower. The second reaction tower and the third reaction tower are connected via a second connecting pipe connecting the upper end of the second reaction tower to the upper end of the third reaction tower. The third reaction tower and the fourth reaction tower are connected via a third connecting pipe connecting the lower end of the third reaction tower to the lower end of the fourth reaction tower.

[0012] In the past, in facilities for producing unsaturated alcohols by reducing unsaturated fatty acid alkyl esters, appropriate catalyst compositions and shapes have been investigated to improve productivity. The reduction reaction of unsaturated fatty acid alkyl esters is a reaction in a gas-liquid mixed system of liquid unsaturated fatty acid alkyl esters and hydrogen gas, and it has been considered essential to control the contact state between the solid catalyst and the gas-liquid mixed system. On the other hand, there has been a demand for facilities that can produce unsaturated alcohols of sufficient quality at practical costs, even when the laboratory scale is expanded to an industrial production scale (e.g., production volume of 10 t / day or more).

[0013] The inventors recognized that the impurities (products other than the target product) generated in the process of reducing unsaturated fatty acid alkyl esters are "hydrocarbons further generated from the alcohol generated from the ester" and "saturated alcohols generated by over-reaction," and investigated the configuration of equipment that can sufficiently promote the unsaturated reduction while suppressing the generation of these impurities. They found that unsaturated alcohols can be obtained in high yields by providing a reaction section in which multiple reaction towers are connected to each other and by alternately repeating a downflow cocurrent flow mode and an upflow cocurrent flow mode in the multiple reaction towers.

[0014] In the production facility according to the present disclosure, four reaction towers, numbered first through fourth, are connected to one another. In the first and third reaction towers, the unsaturated fatty acid alkyl ester (the substance to be reduced) and hydrogen gas flow down in parallel, while in the second and fourth reaction towers, the unsaturated fatty acid alkyl ester and hydrogen gas flow up in parallel. Without being bound by theory, this configuration is believed to ensure that the unsaturated fatty acid alkyl ester and hydrogen gas are mixed thoroughly while coming into contact with the catalyst, and the reduction reaction proceeds smoothly, thereby suppressing side reactions and overreactions.

[0015] In the production facility, each of the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower may include a reaction chamber having a ratio (H / D) of height (H (m)) to inner diameter (D (m)) of 20 to 30. When the reaction tower has such a shape, it is considered that a long reaction path can be secured and the catalyst and the reaction mixture can be reliably contacted with each other.

[0016] In the production facility, each of the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower may be provided with a plurality of heating jackets spaced apart from each other above and below, and each of the plurality of heating jackets may be provided with a valve capable of adjusting the flow rate of a heat transfer medium. With this configuration, it is possible to precisely adjust the temperature in each reaction tower, and it becomes possible to stably proceed with the reaction.

[0017] In the production facility, the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower may be installed on a mounting surface at the same height, and the connection order may be changeable by rearranging the piping. This configuration makes it possible to rearrange the reaction towers at an appropriate time in response to changes in catalyst performance with use, and to provide consistent reaction conditions regardless of the connection order of the reaction towers. This enables stable production of unsaturated alcohols.

[0018] The production facility may further include a distillation apparatus downstream of the fourth reactor, a gas-liquid separator between the fourth reactor and the distillation apparatus, and the gas-liquid separator may include a hydrogen gas reflux pipe connected to the hydrogen gas supply pipe. With this configuration, unused hydrogen gas can be reused in the reduction reaction, thereby improving the utilization efficiency of the raw material.

[0019] The production method according to the present disclosure is a method for producing an unsaturated alcohol by reducing an unsaturated fatty acid alkyl ester in the presence of a catalyst. The production method includes the steps of charging a reaction tower with an unsaturated fatty acid alkyl ester (wherein the alkyl ester has 1 to 4 alkyl carbon atoms) and an aliphatic monoalcohol having 1 to 4 carbon atoms, and supplying hydrogen to the reaction tower to obtain the unsaturated alcohol by a reduction reaction. The reaction tower is a reaction tower included in a reaction section that includes a first reaction tower, a second reaction tower, a third reaction tower, and a fourth reaction tower connected to each other in this order.

[0020] In the past, in methods for producing unsaturated alcohols by reducing unsaturated fatty acid alkyl esters, appropriate catalyst compositions, forms, reaction conditions, etc. have been investigated to improve productivity. Furthermore, production methods for obtaining unsaturated alcohols with good liquid retention and low cloud points have also been investigated. On the other hand, there is a demand for a method that can produce unsaturated alcohols of sufficient quality at a practical cost even when the laboratory scale is expanded to an industrial production scale (e.g., production volume of 10 t / day or more).

[0021] The inventors recognized that impurities (products other than the target product) generated during the process of reducing unsaturated fatty acid alkyl esters are hydrocarbons further generated from the alcohol produced from the esters and saturated alcohols generated by overreaction. They then conducted extensive research into a technology for reducing only the ester to alcohol without reducing the double bonds in the unsaturated aliphatic groups. As a result, they discovered that by adding a C1-C4 aliphatic alcohol along with the raw material unsaturated fatty acid alkyl ester, the generation of by-products can be suppressed and unsaturated alcohols of stable quality can be produced with excellent production efficiency. One of the features of the production method disclosed herein is that a commonly used raw material aliphatic alcohol having C1-C4 is added in addition to the raw material unsaturated fatty acid alkyl ester. The production method disclosed herein does not require special processes or materials and can be implemented industrially without increasing costs.

[0022] Without being bound by theory, it is believed that by charging an aliphatic alcohol having 1 to 4 carbon atoms together with the raw material unsaturated fatty acid alkyl ester, the unsaturated alcohol produced in the reaction system is prevented from being adsorbed back onto the catalyst, thereby preventing side reactions and over-reactions.

[0023] In the production method, the unsaturated fatty acid alkyl ester may be an unsaturated fatty acid alkyl ester derived from an animal or plant and having an acid value of 0 to 10, and the aliphatic alcohol having 1 to 4 carbon atoms may be methanol.

[0024] In the production method, the amount of the aliphatic alcohol charged relative to the unsaturated fatty acid alkyl ester may be 8 parts by mass or more and 15 parts by mass or less per 1 part by mass of the unsaturated fatty acid alkyl ester.

[0025] In the above-described production method, each of the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower may be a fixed-bed reaction tower packed with a granular zinc-based solid catalyst. Among the first reaction tower to the fourth reaction tower, the first reaction tower and the third reaction tower may be configured so that the unsaturated fatty acid alkyl ester, the aliphatic alcohol, and the hydrogen gas flow down in parallel, and the second reaction tower and the fourth reaction tower may be configured so that the unsaturated fatty acid alkyl ester, the aliphatic alcohol, and the hydrogen gas flow up in parallel.

[0026] In the production method, the step of obtaining an unsaturated alcohol by the reduction reaction may be carried out so that the reaction product obtained from a sampling line arranged downstream of the outlet end of the fourth reaction tower has a ketone value (SV) of 4.0 to 7.0, and a step of distilling the obtained reaction product may be carried out following the step of obtaining the unsaturated alcohol.

[0027] In the production method, the zinc-based solid catalyst may be a cylindrical solid catalyst having a diameter of 3 to 5 mm and a height of 3 to 5 mm, and each of the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower may have a cylindrical reaction chamber having an inner diameter of 0.45 to 0.55 m and a height of 11 to 13 m, and the supply amount of hydrogen gas to the first reaction tower may be 3 to 21 m. ３ / h.

[0028] In the production method, the temperature difference between the inlet end temperature of the first reaction tower and the outlet end temperature of the second reaction tower may be 20 to 60°C, and the temperature difference between the inlet end temperature of the third reaction tower and the outlet end temperature of the fourth reaction tower may be 0 to 20°C.

[0029] The manufacturing method may be carried out in the manufacturing facility.

[0030] The production of unsaturated alcohols in the production facility according to the present disclosure will be described in more detail below.

[0031] (Raw materials used in production) The unsaturated alcohol produced in the production facility according to the present disclosure is made from an unsaturated fatty acid alkyl ester as a raw material. The unsaturated fatty acid alkyl ester may be, for example, an unsaturated fatty acid alkyl ester obtained by esterification of an unsaturated fatty acid.

[0032] The unsaturated fatty acids used as raw materials for the unsaturated fatty acid alkyl esters may be vegetable unsaturated fatty acids derived from coconut oil, palm kernel oil, palm oil, olive oil, soybean oil, low-erucic rapeseed oil, high-erucic rapeseed oil, safflower oil, corn oil, cottonseed oil, sunflower oil, rice bran oil, linseed oil, etc., and / or animal unsaturated fatty acids derived from beef tallow, lard, chicken oil, whale oil, fish oil, etc. These unsaturated fatty acids are typically mixtures of unsaturated fatty acids having 16 to 22 carbon atoms. One or more lower alkyl esters, particularly methyl esters, of these unsaturated fatty acids are preferably used as raw materials for the unsaturated alcohols. Specific examples of unsaturated fatty acid alkyl esters include methyl oleate.

[0033] The unsaturated fatty acids can be obtained by hydrolyzing fats and oils according to a conventional method. The unsaturated fatty acid alkyl esters can be obtained by esterifying the unsaturated fatty acids obtained by hydrolysis of fats and oils with a lower alcohol (for example, an aliphatic alcohol having 1 to 4 carbon atoms, such as methyl alcohol). Alternatively, they can be obtained by transesterification of vegetable fats and oils with an aliphatic alcohol having 1 to 4 carbon atoms, such as methyl alcohol.

[0034] The iodine value of the unsaturated fatty acid alkyl ester used as a raw material is preferably 40 to 200. The acid value (residual acid value) of the unsaturated fatty acid alkyl ester is preferably 0 to 10.

[0035] (Alcohol) In the production method according to the present disclosure, an aliphatic alcohol having 1 to 4 carbon atoms is charged into the reaction column together with the above-mentioned raw materials. The aliphatic alcohol having 1 to 4 carbon atoms may be one or more selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, and butanol. It is preferable to use methanol as the alcohol.

[0036] (Catalyst) The catalyst used for ester reduction is preferably a zinc-based solid catalyst. Examples of zinc-based catalysts include zinc-chromium oxide, zinc-aluminum oxide, zinc-aluminum-chromium oxide, zinc-chromium-manganese oxide, zinc-iron oxide, and zinc-iron-aluminum oxide. These zinc-based solid catalysts can be suitably used in the reaction of reducing unsaturated fatty acid alkyl esters to unsaturated alcohols. Of these zinc-based catalysts, zinc-chromium oxide is particularly preferred. The zinc-based catalysts can be used alone or in combination of two or more.

[0037] It is most preferable that the zinc-based catalyst is substantially free of copper. If it contains copper, the copper content is preferably 20 ppm or less, particularly 10 ppm or less. If the copper content is within the above range, the cloud point of the resulting unsaturated alcohol is prevented from becoming too high.

[0038] The zinc-based catalyst may be in the form of fine particles and may be supported on a carrier, such as silica, alumina, silica-alumina, titania, diatomaceous earth, clay, activated carbon, carbon, graphite, zeolite, clays such as montmorillonite, and alkaline earth silicates.

[0039] The carrier-supported zinc-based catalyst is not particularly limited and can be prepared by a conventionally known method such as an impregnation method, a coprecipitation method, etc. Also, a powder or paste containing the zinc-based catalyst and the carrier can be used as a raw material to form a molded catalyst into an appropriate shape using a conventionally known tablet press, granulator, extruder, etc.

[0040] The shape of the catalyst may be a cylinder, a hollow cylinder, a trilobe prism, a quadrilobe prism, a sphere, etc. Two or more catalysts of different shapes may be used in combination. The catalyst is preferably cylindrical.

[0041] The size of the catalyst may be such that its minimum length is approximately 1 to 10 mm, and preferably 3 to 5 mm. Here, "minimum length" refers to, for example, when the catalyst is a spherical catalyst with a diameter of 5 mm, the minimum length is 5 mm in diameter. When the catalyst is a cylindrical catalyst with a diameter of 3 mm and a height of 5 mm, the minimum length is 3 mm in diameter. Furthermore, when the catalyst is a hollow cylinder, for example, a hollow cylinder with an outer diameter of 3 mm (inner diameter of 2 mm) and a height of 5 mm, the minimum length is an outer diameter of 3 mm.

[0042] Regarding catalyst strength, catalysts having a catalyst strength of 1.0 kg or more per catalyst can be used. The catalyst strength is determined by measuring the minimum crushing strength of 100 catalysts individually, calculating the average value A and standard deviation (σ) thereof, and then applying the formula: A-2σ. The catalyst strength may be 1.0 kg or more, and is preferably 1.5 to 4.0 kg.

[0043] The minimum crushing strength is measured in accordance with JIS Z-8841-1993 "3.1 Crushing Strength Test Method." The "minimum crushing strength" refers to the smaller of the crushing strength measured when a catalyst having a shape such as a cylinder is compressed in the vertical direction (axial direction) and the crushing strength measured when it is compressed in the horizontal direction (radial direction, i.e., the direction perpendicular to the axial direction). In the case of a catalyst having a highly symmetrical shape such as a sphere or cube, there is generally no difference in crushing strength depending on the direction of compression, and therefore the crushing strength measured in accordance with the above-mentioned JIS method is taken as the minimum crushing strength.

[0044] The catalyst may be used as it is after being packed into the reaction column, or it is preferable to subject it to an activation treatment before being subjected to the reaction. The activation treatment can be carried out by a known method, for example, by passing hydrogen gas through the reaction column packed with the catalyst.

[0045] (Manufacturing Equipment) Figure 1 is a schematic diagram showing the configuration of a manufacturing equipment according to the present disclosure. The manufacturing equipment according to the present disclosure is suitable for carrying out the manufacturing method according to the present disclosure. In the following description, "upper" and "lower" mean relatively above or below along the vertical direction.

[0046] 1 , the production facility 1 includes a first reaction tower 11, a second reaction tower 12, a third reaction tower 13, and a fourth reaction tower 14, which are connected to each other. These four reaction towers constitute a reaction section. Downstream of the fourth reaction tower 14, a gas-liquid separation device 31, a first distillation device 32, and a second distillation device 33 are provided in this order.

[0047] The first reaction tower 11, the second reaction tower 12, the third reaction tower 13, and the fourth reaction tower 14 are reaction towers of the same shape and the same dimensions, and each is filled with a solid catalyst. The connection order of the reaction towers can be changed by rearranging the piping. In this specification, the reaction towers are referred to as the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower, in order from the side closest to the raw material supply line. When rearranging the reaction towers, as one rearrangement mode, the fourth reaction tower before the rearrangement may be rearranged to the third reaction tower after the rearrangement, and similarly, the third reaction tower may be rearranged to the second reaction tower, the second reaction tower to the first reaction tower, and the first reaction tower to the fourth reaction tower. The first reaction tower 11, the second reaction tower 12, the third reaction tower 13, and the fourth reaction tower 14 are preferably installed on installation surfaces of substantially the same height. An example of an installation surface of substantially the same height is a foundation surface poured on a flat factory site. According to this configuration, even if the connection order of the four reaction towers is rearranged, the vertical positional relationship between them remains unchanged, and a constant reaction path is ensured regardless of the connection order of the four reaction towers.

[0048] The first reaction tower 11 is connected to a pipe 41, which is a raw material supply line connected to the raw material tank 21, and a pipe 51, which is a hydrogen supply line connected to the hydrogen tank 22. Although not shown, devices such as a preheating and temporary storage tank, a heater (heat exchanger), and a pump may be provided between the raw material tank 21 and the first reaction tower 11. The pipes 41 and 51 are connected to the upper part of the first reaction tower 11. That is, the raw material and hydrogen gas are supplied to the first reaction tower 41 from its upper part. The raw material is a liquid, and the raw material and hydrogen gas flow down in parallel within the first reaction tower. The first reaction tower 11 is filled with a catalyst 91 (FIG. 3). The lower part of the first reaction tower 11 is connected to a pipe 42, which is a pipe connecting the first reaction tower 11 and the second reaction tower 12. The pipe 42 may be a pipe with an insulating jacket.

[0049] The pipe 42 is connected to the lower part of the second reaction tower 12. A pipe 43, which is a pipe connecting the second reaction tower 12 and the third reaction tower 13, is connected to the upper part of the second reaction tower 12. The raw material and hydrogen gas introduced into the second reaction tower 12 through the second pipe 42 flow upward in parallel inside the second reaction tower 12 and are discharged from the pipe 43.

[0050] The pipe 43 is connected to the upper part of the third reaction tower 13. A pipe 44, which is a pipe connecting the third reaction tower 13 and the fourth reaction tower 14, is connected to the lower part of the third reaction tower 13. The raw material and hydrogen gas introduced into the third reaction tower 13 through the third pipe 43 flow down in parallel inside the third reaction tower 13 and are discharged from the pipe 44.

[0051] The pipe 44 is connected to the lower part of the fourth reaction tower 14. A pipe 45, which is a pipe connecting the fourth reaction tower 14 and the gas-liquid separation device 31, is connected to the upper part of the fourth reaction tower 14. The raw material and hydrogen gas introduced into the fourth reaction tower 14 through the fourth pipe 44 flow up in parallel inside the fourth reaction tower 14 and are discharged from the pipe 45. The unsaturated fatty acid alkyl ester, which is the raw material, undergoes ester reduction to form an unsaturated alcohol while moving from the first reaction tower 11 to the fourth reaction tower 14. In other words, the first reaction tower 11 to the fourth reaction tower 14 constitute a reduction reaction apparatus, and the gas-liquid separation device 31, the first distillation device 32, and the second distillation device 33 can be said to be facilities for separating and purifying the unsaturated alcohol product from the obtained reaction mixture.

[0052] The gas-liquid separator 31 is, for example, a high-pressure separator. The gas-liquid separator 31 is connected to a pipe 52, which is a return line for returning the hydrogen gas separated from the reaction mixture to the pipe 52, which is a hydrogen supply line. The gas-liquid separator 31 is connected to a first distillation apparatus 32 via a pipe 46. The first distillation apparatus 32 is an initial distillation column, and low-boiling point components are distilled off in the first distillation apparatus 32. Although not shown, multiple connection points from the pipe 46 to the first distillation apparatus 32 may be provided, spaced apart in the vertical direction. The liquid component (crude unsaturated alcohol containing unreacted raw materials) separated in the gas-liquid separator 31 is transferred to the first distillation apparatus 32 through the pipe 46. A transesterification catalyst is introduced during this process. The transesterification in the distillation stage will be described later.

[0053] The first distillation apparatus 32 is connected to the second distillation apparatus 33 via a pipe 47. The second distillation apparatus 33 is a so-called main fraction column. The second distillation apparatus 33 is connected to a product tank 34 and a pitch tank 35. The unsaturated alcohol product is recovered as a distillate from the second distillation apparatus 33 and stored in the product tank 34. The pitch, which is the distillation residue, is recovered in the pitch tank 35 and is reused as part of the reaction raw materials.

[0054] 2 is a cross-sectional schematic diagram showing the shape of the first reaction tower 11. The second reaction tower 12, the third reaction tower 13, and the fourth reaction tower 14 also have the same shape. Referring to FIG. 2, the first reaction tower 11 has a cylindrical reaction chamber V therein. １ and lids 72 and 73 disposed at both ends of the body 71 in the longitudinal direction. １ (i.e., reaction chamber V １ The diameter of the reactor is 0.5 m. １is 12 m. Naturally, the shape of the reaction tower is not limited to this, and the dimensions of each part can be changed. The inner diameter of the reaction chamber may be about 0.4 to 0.8 m, preferably 0.45 to 0.55 m. The height of the reaction tower may be about 10 to 15 m, preferably 11 to 13 m. The ratio (H / D) of the height (H (m)) to the inner diameter dimension (D (m)) of the reaction chamber is preferably 10 to 40, more preferably 20 to 30. Reaction chamber V １ is filled with a solid catalyst.

[0055] The pipes 42, 43, and 44 connecting the reaction columns may have an inner diameter of, for example, about 40 to 80 mm, and preferably about 40 to 60 mm. The length of the pipes 42, 43, and 44 may be, for example, about 4 to 8 m, and preferably about 5 to 7 m.

[0056] The lids 72 and 73 are fixed to the main body 71 by means of bolts or the like. The lid 72 is provided with fluid inlets and outlets 81 and 82 to which raw material supply piping is connected, and a pressure gauge insertion port 83. The lid 73 is provided with fluid inlets and outlets 84 and 85 to which raw material removal piping is connected. Three upper and lower jackets 74, 75, and 76 are provided around the outer periphery of the main body 71. The temperature inside the reaction tower is controlled by circulating a heated heat transfer medium through the jackets 74, 75, and 76. The jackets 74, 75, and 76 are provided with valves 77, 78, and 79, respectively, and the amount of heat transfer medium circulating can be adjusted by adjusting the opening of the valves 77, 78, and 79.

[0057] 3 is a schematic diagram showing the shape of the catalyst and the flow of the reaction system in the production facility according to the present disclosure. In FIG. 3, the reaction raw materials and hydrogen gas flow upward in parallel in the second and fourth reaction towers. Referring to FIG. 3, the catalyst 91 is a cylindrical solid catalyst. The catalyst 91 has a diameter d １ 3.2 mm, height h １ The catalyst 91 is not limited to this size, but may have a diameter of about 3 to 5 mm and a height of about 3 to 5 mm. １For example, when the reaction tower has the dimensions shown in Fig. 2, about 3200 to 3400 kg of catalyst can be packed in one reaction tower.

[0058] As described above, in the second and fourth reaction towers, the reaction raw materials, unsaturated fatty acid alkyl ester and hydrogen gas, flow upward in parallel and come into contact with the catalyst 91, causing the reduction reaction of the ester. In Figure 3, the flow of the reaction liquid (including the unsaturated fatty acid alkyl ester, reaction product, and alcohol) is indicated by the open arrows. Hydrogen gas exists in the reaction liquid as bubbles and rises together with the reaction liquid, as indicated by the black arrows.

[0059] (Production method) The method for producing an unsaturated alcohol carried out in the production equipment according to the present disclosure is suitably carried out in the above-mentioned production equipment. The production method according to the present disclosure includes a charging step and a reduction reaction step, and preferably further includes a distillation step. The production of the unsaturated alcohol may be carried out continuously (continuous method) or batchwise (batch method), but production by a continuous method is preferred. In the case of a continuous method, the charging step, reduction reaction step, and distillation step are carried out continuously, so there may be no clear time division between each step.

[0060] The charging step is a step of charging a raw material and an alcohol into a reaction tower filled with a catalyst. The amount of the raw material unsaturated fatty acid alkyl ester charged may be, for example, 20 to 22 tons per day, and the amount of methanol charged may be, for example, 2 to 2.5 tons per day. The amount of aliphatic alcohol charged relative to the unsaturated fatty acid alkyl ester may be 8 to 15 parts by mass. Within this range, the addition of the aliphatic alcohol has the effect of suppressing the generation of impurities and does not inhibit the reduction reaction of the ester. The unsaturated fatty acid alkyl ester is preferably preheated and supplied to the reaction tower. In addition to the unsaturated fatty acid alkyl ester and the alcohol, hydrogen gas is introduced into the reaction tower. The hydrogen gas is pre-pressurized by a compressor and introduced into the reaction tower. The pressure of the hydrogen gas may be approximately 17 to 20 MPa.

[0061] The reduction reaction step is carried out following the charging step. The reduction reaction step is also called hydrogenation. In the reduction reaction step, unsaturated fatty acid alkyl ester, alcohol, and hydrogen gas (hereinafter, these may be collectively referred to as a raw material mixture) are transferred sequentially from the first reaction tower to the fourth reaction tower in the aforementioned production facility. During this time, the ester is reduced to produce an unsaturated alcohol.

[0062] The temperature of the first reaction tower may be adjusted to 230 to 250°C. The temperature difference between the inlet end temperature and the outlet end temperature of the first reaction tower may be 10 to 20°C. That is, the raw material is heated in the first reaction tower. The pressure of the first reaction tower may be 17 to 20 MPa. The flow rate of the raw material in the first reaction tower may be 400 kg / h to 900 kg / h. The unsaturated fatty acid alkyl ester, alcohol, and hydrogen gas are supplied from the top of the first reaction tower. In the first reaction tower, the raw material mixture flows down in parallel and contacts the catalyst packed in the reaction tower. From the first reaction tower to the fourth reaction tower, the pressure and flow rate in the reaction towers may be approximately constant (with a fluctuation range of ±10% or less).

[0063] The first and second reaction towers are connected via piping, and the raw material mixture withdrawn from the bottom of the first reaction tower is introduced into the second reaction tower from the bottom of the second reaction tower. In the second reaction tower, the raw material mixture flows upward in parallel and contacts the catalyst packed in the reaction tower. The temperature of the second reaction tower may be adjusted to 270 to 300°C, or may be adjusted to 270 to 280°C. The temperature difference between the inlet end temperature and the outlet end temperature of the second reaction tower may be 20 to 50°C. The reduction reaction of the ester mainly proceeds in the second and fourth reaction towers, and it is believed that the reduction reaction of the ester mainly proceeds in the second reaction tower in particular. Heat is generated during the reduction reaction, causing a temperature rise in the second reaction tower. Comparing the inlet end temperature of the first reaction tower with the outlet end temperature of the second reaction tower, it is preferable that the temperature at the outlet end of the second reaction tower is 20 to 60°C higher than the temperature at the inlet end of the first reaction tower.

[0064] The raw material mixture is taken out from the top of the second reaction tower. The raw material mixture moves from the first reaction tower to the second reaction tower naturally following the flow of hydrogen gas (gas flow) fed into the first reaction tower, and an external power source such as a pump is not essential, but the raw material mixture may be transferred by a pump or the like. The same applies to the movement from the second reaction tower to the third reaction tower and the movement from the third reaction tower to the fourth reaction tower.

[0065] The second and third reaction towers are connected via piping, and the raw material mixture withdrawn from the top of the second reaction tower is introduced into the third reaction tower from the top of the third reaction tower. In the third reaction tower, the raw material mixture flows down in parallel and contacts the catalyst packed in the reaction tower. The temperature of the third reaction tower may be adjusted to 270 to 280°C. The temperature difference between the temperature at the inlet end and the temperature at the outlet end of the third reaction tower may be 0 to 10°C. The raw material mixture is withdrawn from the bottom of the third reaction tower.

[0066] The third and fourth reaction towers are connected via piping, and the raw material mixture withdrawn from the bottom of the third reaction tower is introduced into the fourth reaction tower from its bottom. In the fourth reaction tower, the raw material mixture flows upward in parallel and contacts the catalyst packed in the reaction tower. The temperature of the fourth reaction tower may be adjusted to 260 to 280°C. The temperature difference between the inlet end temperature and the outlet end temperature of the fourth reaction tower may be 0 to 10°C. The raw material mixture is withdrawn from the top of the fourth reaction tower. The temperatures in the third and fourth reaction towers may be substantially constant (e.g., the range of fluctuation is ±10% or less). The temperature change in the third and fourth reaction towers is small relative to the temperature change (temperature rise) in the first and second reaction towers. The temperature difference between the inlet end temperature of the third reaction tower and the outlet end temperature of the fourth reaction tower may be 0 to 10°C.

[0067] The progress of the reduction (hydrogenation) reaction can be confirmed, for example, by SV (ketonic value). These can be used as process control values. For example, the reduction reaction step is preferably carried out so that the ketonic value (SV) of the reaction product obtained from a sampling line arranged downstream of the outlet end of the fourth reaction tower is 4.0 to 7.0.

[0068] The reaction time of the reduction reaction (the time from when the raw material mixture is charged into the first reaction tower until it reaches the outlet end of the fourth reaction tower) may be about 5 to 15 hours, and preferably about 7 to 10 hours. The raw material mixture may be continuously transferred from the first reaction tower to the fourth reaction tower without residence time, or a predetermined residence time may be set in each reaction tower.

[0069] The raw material mixture that has undergone the reduction reaction step contains an unsaturated alcohol, which is the reaction product. In order to purify the unsaturated alcohol product, it is preferable to carry out distillation following the reduction reaction. Prior to distillation, the unreacted raw material, unsaturated fatty acid alkyl ester, may be converted to a longer-chain alkyl ester (e.g., a total of 20 to 40 carbon atoms). The conversion to the long-chain alkyl ester can be carried out by a transesterification reaction. By carrying out transesterification, the degree of purification by distillation can be improved, and the contamination of the unsaturated fatty acid alkyl ester, which is the unreacted raw material, with the target unsaturated alcohol can be suppressed.

[0070] The distillation process may be carried out in two stages in equipment equipped with a first distillation column and a main distillation column. The first distillation column may be equipped with multiple inlets for the raw material mixture separated from each other in the vertical direction. The low-boiling components to be distilled off can be controlled by changing the inlet for the raw material mixture used. The fraction from which the low-boiling components have been distilled off is introduced into the main distillation column, where further distillation is carried out. The product unsaturated alcohol is obtained as a distillate separated and recovered in the main distillation column. The distillation residue is recovered as pitch from the bottom of the main distillation column and may be temporarily stored in a pitch tank before being reused as a reaction raw material.

[0071] The method for producing unsaturated alcohols may further include a slight hydrogenation step. Slight hydrogenation refers to a step in which conjugated diene bonds are substantially selectively hydrogenated to monoene bonds, resulting in hydrogenation without causing an increase in the cloud point. When slight hydrogenation is performed, it is usually preferable to use a copper-containing catalyst as the slight hydrogenation catalyst. Examples of copper-containing catalysts include copper, copper-zinc, copper-chromium, copper-zinc-chromium, and oxides thereof, as well as modified catalysts obtained by adding molybdenum, tungsten, magnesium, barium, aluminum, calcium, zirconium, manganese, and oxides thereof to these.

[0072] When slight hydrogenation is carried out, the reaction method is not particularly limited, and methods such as a batch suspension bed reaction, a continuous suspension bed reaction, and a fixed bed continuous reaction can be used. In the case of a batch or continuous suspension bed reaction, the reaction temperature may be about 100 to 200°C. The reaction pressure may be about 1 MPa to atmospheric pressure. When the slight hydrogenation reaction is carried out by a fixed bed continuous reaction, it is preferable to pack the formed catalyst into a reaction tower, activate the catalyst, and then carry out the reaction by allowing the raw material unsaturated alcohol and hydrogen to flow downward or upward in a cocurrent manner. The reaction temperature may be about 50 to 150°C. The reaction pressure may be about 1 MPa to atmospheric pressure.

[0073] The production of unsaturated alcohols may further be subjected to deodorization. When deodorization is performed, the deodorization operation can be carried out after distillation or slight hydrogenation, etc. When deodorization is performed, it is most preferable to carry out the deodorization immediately before commercialization. As the deodorization method, a method known as a method for deodorizing unsaturated alcohols and the like can be used. Examples of such known methods include steam deodorization, reduced pressure topping, thin film distillation, activated carbon adsorption, etc. In particular, steam deodorization is preferred. Steam deodorization can also be used in combination with other deodorization methods.

[0074] When steam deodorization is performed, deodorization can be carried out by blowing steam into the unsaturated alcohol under conditions of a temperature of about 100 to 200° C. and a pressure of about 0.1 to 70 kPa. The amount of steam blown in can be, for example, about 0.1 to 20% by mass, calculated as the mass of water, relative to the unsaturated alcohol.

[0075] [Example 1] 1) Apparatus The production equipment shown in Figure 1 was used. As mentioned above, the first, second, third, and fourth reaction towers were all identical in shape, with the reaction chambers each having a diameter of 50 cm and a height of 12 m. The reaction chambers were filled with a catalyst. Each tower was filled with 3,200 to 3,400 kg of catalyst. The reaction towers were equipped with a heat transfer medium jacket on the outside of the reaction tower. In each reaction tower, the heat transfer medium jacket was divided into three sections in the vertical direction, allowing for precise control of the temperature in the vertical direction of the reaction tower. The reaction towers were connected by piping equipped with an insulation jacket.

[0076] 2) Catalyst Composition: Zn-Cr catalyst (manufactured by JGC Catalysts and Chemicals Co., Ltd.) Diameter: 3.2 mm, length: 3.2 mm, cross-sectional shape: circular Average crushing strength: 405 to 423 N / particle Specific surface area: 41 to 44 m ２ / g Pore volume: 0.23 to 0.26 mL / g Catalyst charge amount: approximately 3,200 to 3,400 kg per reactor 3) Raw materials Unsaturated fatty acid alkyl ester: palm oil-derived oleic acid methyl ester Methanol

[0077] 4) Operation: 20 to 22 t / day of palm oil-derived oleic acid methyl ester as the raw material was supplied to the first reactor at a rate of 2 to 2.5 t / day of methanol. Hydrogen gas adjusted to 17.9 MPa by a compressor was also supplied to the first reactor. The pressure was almost constant up to the fourth reactor. The flow rate of the hydrogen gas was 12.3 Nm ３ / h. The inlet temperature of the first reaction tower was 239.5°C, and the outlet temperature of the first reaction tower was 245.0°C. The raw material was heated in the first reaction tower. In the first reaction tower, the raw material was heated by circulating a heat medium through the heat medium jacket. The inlet temperature of the second reaction tower was 268.9°C, and the outlet temperature of the first reaction tower was 293.8°C. In the second reaction tower, the temperature rose due to the heat of reaction accompanying the reduction reaction of the ester. The inlet temperature of the third reaction tower was 273.3°C, and the outlet temperature of the third reaction tower was 275.2°C. The inlet temperature of the fourth reaction tower was 263.8°C, and the outlet temperature of the fourth reaction tower was 261.2°C. The temperature was almost constant throughout the third and fourth reaction towers. The reaction time was 10 hours. The ketone value of the sample after the unsaturation reduction step was 6.0 to 6.7. After the unsaturated reduction step, a distillation step was carried out, and after methanol and the initial fraction were distilled off, the product unsaturated alcohol and pitch were separated in the main distillation column. The yield after distillation was 85 to 90%.

[0078] The present invention is intended to cover a wide range of applications, including those related to the present invention, including those related to the present invention.

[0079] 1 Manufacturing equipment, 11 First reaction tower, 12 Second reaction tower, 13 Third reaction tower, 14 Fourth reaction tower, 21 Raw material tank, 22 Hydrogen tank, 23 Transesterification catalyst, 31 Gas-liquid separator, 32 First distillation apparatus, 33 Second distillation apparatus, 34 Product tank, 35 Pitch tank, 41, 42, 43, 44, 45, 46, 47, 51, 52 Piping, 71 Main body, 72, 73 Cover, 74, 75, 76 Jacket, 77, 78, 79 Valve, 81, 82, 84, 85 Fluid inlet / outlet, 83 Pressure gauge insertion port, 91 Catalyst.

Claims

1. An unsaturated alcohol production facility comprising a reaction section including a first reaction tower, a second reaction tower, a third reaction tower, and a fourth reaction tower connected to each other in this order, wherein the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower are each filled with a granular solid catalyst, the first reaction tower has a raw material supply pipe and a hydrogen gas supply pipe connected to its upper side, the first reaction tower and the second reaction tower are connected via a first connecting pipe that connects the lower end of the first reaction tower with the lower end of the second reaction tower, the second reaction tower and the third reaction tower are connected via a second connecting pipe that connects the upper end of the second reaction tower with the upper end of the third reaction tower, and the third reaction tower and the fourth reaction tower are connected via a third connecting pipe that connects the lower end of the third reaction tower with the lower end of the fourth reaction tower.

2. The unsaturated alcohol production facility according to claim 1, wherein each of the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower comprises a reaction chamber having a ratio (H / D) of height (H (m)) to inner diameter (D (m)) of 20 to 30.

3. The unsaturated alcohol production facility according to claim 1 or 2, wherein each of the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower is equipped with a plurality of heating jackets spaced apart from each other above and below, and each of the plurality of heating jackets is equipped with a valve capable of adjusting the flow rate of the heat medium.

4. The unsaturated alcohol production equipment according to claim 1 or 2, wherein the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower are installed on an installation surface at the same height, and the connection order can be changed by rearranging the piping.

5. The unsaturated alcohol production facility according to claim 1 or 2, further comprising a distillation apparatus downstream of the fourth reactor, and a gas-liquid separator between the fourth reactor and the distillation apparatus, the gas-liquid separator comprising a hydrogen gas reflux pipe connected to the hydrogen gas supply pipe.

6. A method for producing unsaturated alcohols by reducing unsaturated fatty acid alkyl esters in the presence of a catalyst, comprising: a step of charging a reaction tower with an unsaturated fatty acid alkyl ester (wherein the alkyl ester has 1 to 4 alkyl carbon atoms) and an aliphatic alcohol having 1 to 4 carbon atoms; and a step of supplying hydrogen to the reaction tower and obtaining an unsaturated alcohol by a reduction reaction, wherein the reaction tower is a reaction tower included in a reaction section that includes a first reaction tower, a second reaction tower, a third reaction tower, and a fourth reaction tower connected to each other in this order.

7. The method for producing an unsaturated alcohol according to claim 6, wherein the unsaturated fatty acid alkyl ester is an unsaturated fatty acid alkyl ester derived from an animal or plant and having an acid value of 0 to 10, and the aliphatic alcohol having 1 to 4 carbon atoms is methanol.

8. The method for producing an unsaturated alcohol according to claim 6 or 7, wherein the amount of the aliphatic alcohol charged relative to the unsaturated fatty acid alkyl ester is 8 parts by mass or more and 15 parts by mass or less per 1 part by mass of the unsaturated fatty acid alkyl ester.

9. The method for producing unsaturated alcohols according to claim 6 or 7, wherein each of the first reaction tower, the second reaction tower, the third reaction tower and the fourth reaction tower is a fixed-bed reaction tower packed with a granular zinc-based solid catalyst, and among the first reaction tower to the fourth reaction tower, the first reaction tower and the third reaction tower are configured so that the unsaturated fatty acid alkyl ester, the aliphatic alcohol and the hydrogen gas flow down in parallel, and the second reaction tower and the fourth reaction tower are configured so that the unsaturated fatty acid alkyl ester, the aliphatic alcohol and the hydrogen gas flow up in parallel.

10. The method for producing unsaturated alcohol according to claim 6 or 7, wherein the step of obtaining unsaturated alcohol by the reduction reaction is carried out so that the reaction product obtained from a sampling line located downstream of the outlet end of the fourth reaction tower has a ketone value (SV) of 4.0 to 7.0, and then a step of distilling the obtained reaction product is carried out.

11. The zinc-based solid catalyst is a cylindrical solid catalyst having a diameter of 3 to 5 mm and a height of 3 to 5 mm, and each of the first reaction tower, the second reaction tower, the third reaction tower, and the fourth reaction tower has a cylindrical reaction chamber having an inner diameter of 0.45 to 0.55 m and a height of 11 to 13 m, and the supply rate of hydrogen gas to the first reaction tower is 3 to 21 m ３ The method for producing an unsaturated alcohol according to claim 6 or 7, wherein the reaction time is 100-1500 s / h.

12. The method for producing unsaturated alcohols according to claim 6 or 7, wherein the temperature difference between the inlet end temperature of the first reaction tower and the outlet end temperature of the second reaction tower is 20 to 60°C, and the temperature difference between the inlet end temperature of the third reaction tower and the outlet end temperature of the fourth reaction tower is 0 to 20°C.

13. A method for producing an unsaturated alcohol according to claim 9, which is carried out in the unsaturated alcohol production facility according to claim 1 or 2.

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