Method for discharging crystal grain-containing slurry from container

Abstract

Provided is a method for properly treating grains. The present invention pertains to, for example, a method for supplying a crystal grain melt-containing liquid into a container and discharging a crystal grain-containing slurry from the container, wherein the container includes therein at least one liquid supply unit having a liquid jetting port for ejecting the melt-containing liquid into the container, the liquid supply unit has: a liquid ejection portion formed by M or more liquid jetting ports as calculated according to predetermined requirements; and a liquid supply region for supplying the liquid ejection portion with the liquid from the outside of the container, and the liquid is ejected in a plurality of substantially horizontal different directions from the liquid ejection portion and supplied to the container through each liquid jetting port at a liquid jet speed of at least 2 m / s.

Description

Method for discharging slurry containing crystal grains from a container

[0001] The present invention relates to a method for discharging a slurry containing crystal grains from a container, and more particularly to a method for discharging a slurry containing crystal grains from a container, and a method for producing a compound.

[0002] Handling of crystal grains is essential in many cases, such as in the production and purification of chemical products, and there are many opportunities to handle them on an industrial scale. For example, even in the case of easily polymerizable compounds such as (meth)acrylic acid, handling of crystal grains is required when the compound is produced and purified as a raw material for resins, etc. In this situation, various methods for handling crystal grains have been investigated.

[0003] In industry, most crude compounds are purified through a continuous purification process. For example, a method for producing acrylic acid has been disclosed in which an acrylic acid-containing gas obtained by catalytic gas-phase oxidation of a raw material gas is collected and purified by crystallization, and a Michael adduct of acrylic acid contained in the residual mother liquor is decomposed and returned to the collection step (see, for example, Patent Document 1). This method makes it possible to produce acrylic acid in a high yield.

[0004] In the above purification step, a wash column such as a hydraulic wash column (HWC) may be used. For example, conventional purification methods using a wash column are disclosed in Patent Documents 2 to 4.

[0005] JP 2007-182437 A European Patent No. 1469926 Specification JP 2005-509010 A Japanese Patent Laid-Open No. 11-123302 A

[0006] As described above, there has been a demand for an excellent method for handling crystal grains. The present invention has been made in view of the above-described current situation, and an object of the present invention is to provide a method for appropriately handling crystal grains.

[0007] The present inventors have investigated methods for appropriately handling crystal grains, and have focused on a method for handling crystal grains by spraying a liquid in a vessel, such as a hydraulic washing column, which has high cleaning efficiency, and breaking up a crystal bed by liquid dynamic pressure. The present inventors have discovered a method for supplying a liquid containing a melt of crystal grains into a vessel and discharging a slurry containing crystal grains from the vessel, the vessel comprising at least one liquid supply unit having a liquid jet outlet for spraying the liquid containing the melt into the vessel, the liquid supply unit having a liquid jetting section formed by M or more liquid jetting outlets calculated according to predetermined requirements, and a liquid supply region for supplying liquid from outside the vessel to the liquid jetting section, the liquid jetting section jetting liquid in a plurality of different, substantially horizontal directions, and supplying the liquid to the vessel through each liquid jetting outlet at a liquid jetting speed of 2 m / s or more, thereby enabling substantially uniform handling of the crystal grains, such as substantially uniformly breaking up the crystal bed by liquid dynamic pressure, thereby enabling substantially uniform cleaning and resulting in excellent quality products. Based on this discovery, the present invention has been completed.

[0008] That is, the present invention (1) is a method for supplying a liquid containing a melt of crystal grains into a container and discharging a slurry containing the crystal grains from the container, wherein the container is equipped with at least one liquid supply unit having a liquid ejection port therein for ejecting the liquid containing the melt into the container, and the liquid supply unit has a liquid ejection section formed by M or more liquid ejection ports calculated according to the following requirements, and a liquid supply area for supplying liquid from outside the container to the liquid ejection section, and the liquid is ejected from the liquid ejection section in a plurality of different, approximately horizontal directions, and supplied to the container through each liquid ejection port at a liquid ejection speed of 2 m / s or more. Requirements: M is the value (decimals are rounded down) obtained by dividing 360 by one of the following values: 1) The spread angle (°) when water is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in water. 2) The spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in flow analysis (numerical calculation).

[0009] The present invention (2) is a method of the present invention (1), in which, in at least one of the liquid supply units, when viewed from above and below, all horizontal jetting difference angles are approximately the same when the angle formed by the jetting direction of liquid ejected from a liquid ejection outlet and the jetting direction of liquid ejected from a liquid ejection outlet adjacent to the liquid ejection outlet is taken as the horizontal jetting difference angle.

[0010] The present invention (3) is a method according to the present invention (1) or (2), in which the positions of the liquid ejection ports forming the liquid ejection portion are arranged on a circle whose center is at the liquid ejection portion when viewed from above and below.

[0011] The present invention (4) is a method of any combination with any of the present inventions (1) to (3), in which in at least one of the liquid supply units, the liquid outlets are located at two or more different heights when viewed horizontally.

[0012] The present invention (5) is a method in any combination with any of the present inventions (1) to (4), in which the slurry is discharged from at least four directions of the container at a linear velocity of 1 m / s or more.

[0013] The present invention (6) is a method for producing a compound using a hydraulic washing column, the hydraulic washing column comprising at least one circulating liquid supply unit having therein a circulating liquid jet port for jetting a circulating liquid containing a melt of crystal grains into the hydraulic washing column, the circulating liquid supply unit having a circulating liquid jetting section formed by M or more circulating liquid jet ports calculated according to the following requirements, and a circulating liquid supply region for supplying the circulating liquid from outside the hydraulic washing column to the circulating liquid jetting section, the circulating liquid being jetted from the circulating liquid jetting section in a plurality of different substantially horizontal directions, and being supplied into the hydraulic washing column through each of the circulating liquid jet ports at a circulating liquid jetting velocity of 2 m / s or more, and the amount of liquid jetted from each circulating liquid jet port is 10 kg / h or more. Requirements: M is the value (decimals truncated) obtained by dividing 360 by one of the following values: 1) The spread angle (°) when water is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in water. 2) The spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in flow analysis (numerical calculation).

[0014] In the present invention (7), the number of the circulating liquid supply units is 30 to 90 cm when viewed from the top and bottom of the hydraulic washing column. ２ This is the manufacturing method of the present invention (6), which is worth 1 point.

[0015] The present invention (8) is the production method according to the present invention (6) or (7), wherein the temperature of the circulating liquid is the melting point of the compound plus 1° C. or more.

[0016] The present invention (9) is a method for producing a compound in any combination with any of the present inventions (6) to (8), wherein the compound is an organic compound having a higher solid density than a liquid density.

[0017] The present invention (10) is a method for producing an arbitrary combination with any of the present inventions (6) to (9), in which the compound is (meth)acrylic acid.

[0018] The present invention (11) is a method for supplying a liquid containing a melt of crystal grains into a container and discharging a slurry containing the crystal grains from the container, wherein the container has at least one liquid supply unit therein having a liquid jetting outlet for jetting the liquid containing the melt into the container, and the liquid supply unit has a liquid jetting section formed by M or more liquid jetting outlets calculated according to the following requirements, and a liquid supply area for supplying liquid from outside the container to the liquid jetting section, and the liquid is jetted from the liquid jetting section in a plurality of different, approximately horizontal directions, and supplied to the container through each liquid jetting outlet at a liquid jetting speed of 0.3 m / s or more. Requirements: M is the value (decimals are rounded down) obtained by dividing 360 by one of the following values: 1) The spread angle (°) when water is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in water. 2) The spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in flow analysis (numerical calculation).

[0019] The present invention (12) is a method for producing a compound using a hydraulic washing column, the hydraulic washing column comprising at least one circulating liquid supply unit having therein a circulating liquid jet port for jetting a circulating liquid containing a melt of crystal grains into the hydraulic washing column, the circulating liquid supply unit having a circulating liquid jetting section formed by M or more circulating liquid jet ports calculated according to the following requirements, and a circulating liquid supply region for supplying the circulating liquid from outside the hydraulic washing column to the circulating liquid jetting section, the circulating liquid being jetted from the circulating liquid jetting section in a plurality of different substantially horizontal directions, and being supplied into the hydraulic washing column through each of the circulating liquid jet ports at a circulating liquid jetting velocity of 0.3 m / s or more, and the amount of liquid jetted from each circulating liquid jet port is 1.5 kg / h or more. Requirements: M is the value (decimals truncated) obtained by dividing 360 by one of the following values: 1) The spread angle (°) when water is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in water. 2) The spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in flow analysis (numerical calculation).

[0020] The above-mentioned Patent Documents 2 to 4 contain descriptions related to washing columns, and Patent Document 2 describes spraying a washing liquid as a jet from a guide device, but does not disclose the number of openings or the spraying speed for this purpose, nor does it disclose adjusting the number of openings and the spraying speed to handle the crystal grains approximately uniformly. Furthermore, Patent Document 3 describes a rotary cutter disk for carrying out acrylic acid crystals from a crystal bed, and Patent Document 4 describes using a heat transfer tube in the heating and melting section of a washing column to break up the crystal bed, but Patent Documents 3 and 4 do not describe spraying a liquid to handle the crystal grains by liquid dynamic pressure.

[0021] The method of the present invention allows for substantially uniform handling of the crystals in a vessel such as a hydraulic wash column.

[0022] Fig. 1 is a schematic diagram illustrating a container according to the method of the present invention, and Fig. 2 is a schematic diagram illustrating a liquid supply unit according to the method of the present invention.

[0023] The present invention will be described in detail below. Note that a combination of two or more of the individual preferred features of the present invention described below is also a preferred embodiment of the present invention.

[0024] In the following, first, a method for discharging the slurry containing the crystal grains of the present invention from a container will be described, followed by a method for producing the compound of the present invention.

[0025] (Method for discharging a slurry containing crystal grains from a container) A method for discharging a slurry containing crystal grains from a container of the present invention is, for example, a method for supplying a liquid containing a melt of crystal grains into a container and discharging the slurry containing crystal grains from the container, wherein the container is equipped with at least one liquid supply unit therein having a liquid ejection port for ejecting the liquid containing the melt into the container, and the liquid supply unit has a liquid ejection portion formed by M or more liquid ejection ports calculated according to the following requirements, and a liquid supply area for supplying liquid from outside the container to the liquid ejection portion, and the liquid is ejected from the liquid ejection portion in a plurality of different approximately horizontal directions, and supplied to the container through each liquid ejection port at a liquid ejection speed of 2 m / s or more. Requirements: M is the value (decimals are rounded down) obtained by dividing 360 by one of the following values: 1) The spread angle (°) when water is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in water. 2) The spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in flow analysis (numerical calculation).

[0026] In the method of the present invention, the liquid jetting section is formed by M or more liquid jetting ports calculated according to the above requirements, so that the product of the number of M or more liquid jetting ports and the expansion angle of the liquid jetting ports is 360 or more. This makes it possible to jet liquid sufficiently around the liquid supply unit, and to handle the crystal grains approximately uniformly.

[0027] In determining the spread angle in 1) and 2), the "single liquid jet nozzle equivalent to the above" refers to a jet nozzle that is approximately identical in thickness around the jet nozzle and in shape and size to the liquid jet nozzle of the liquid supply unit used in the method of the present invention. Note that the "single liquid jet nozzle equivalent to the above" may be any jet nozzle that is approximately identical in thickness around the jet nozzle and in shape and size to the liquid jet nozzle of the liquid supply unit. It is not necessary to prepare the same device as the liquid supply unit and use a jet nozzle provided in that device; it is not particularly limited as long as it has an opening. Note that the "approximately identical" jet nozzle thickness refers to a range of ±50% in thickness (mm). The "approximately identical" jet nozzle size refers to a range of ±0.5 mm in length, width, and diameter (mm).

[0028] The "equivalent speed" in 1) and 2) above means that the linear speed (m / s) is the same as the liquid ejection speed through the liquid ejection port in the method of the present invention, rounded off to one decimal place.

[0029] As the "water" in 1) above, tap water or industrial water that has been colored (colored water) can be used. As the "liquid with equivalent physical properties" in 2) above, the viscosity (cP) and density (kg / m) of the liquid to be sprayed in the method of the present invention can be used. ３ The viscosity and temperature (°C) must be the same to the nearest integer when rounded off to the first decimal place, and the density must be within ±5%. The viscosity is measured, for example, using a tuning fork vibration viscometer under conditions of room temperature and normal pressure.

[0030] When measuring the spread angle in 1) above, an opening of the same shape and size as the liquid outlet of the liquid supply unit is made on the side of a nozzle or the like, made of the same material and thickness as the periphery of the liquid outlet of the liquid supply unit, and water is sprayed horizontally from the opening until the pressure stabilizes, after which the valve is switched to spray the colored water horizontally.The distance, width, and behavior of the spray from the opening are then observed and recorded from above to measure.

[0031] In the above 2), software manufactured by SIEMENS is used for flow analysis (numerical calculation), but the software is not limited to this. In both the above 1) and 2), the unit of the expansion angle is degrees (°).

[0032] In the liquid supply unit used in the method of the present invention, it is preferable that the liquid jetting nozzles, the physical properties, and the velocity of the liquid jetted from the liquid jetting nozzles are all equivalent, and it is also preferable that the spread angle of the liquid from each liquid jetting nozzle is all equivalent, but if, for example, the liquid jetting nozzles of the liquid supply unit and the physical properties and velocity of the liquid jetted from the liquid jetting nozzles are not all equivalent, the spread angle may differ from one liquid jetting nozzle to another. In this way, if the liquid jetting nozzles of the liquid supply unit and the physical properties and velocity of the liquid jetted from the liquid jetting nozzles are not all equivalent, the spread angle is measured for each liquid jetting nozzle by the above method 1) or 2).

[0033] Furthermore, in the above requirements, if the value (decimals rounded down) obtained by dividing 360 by the value related to 1) above is different from the value (decimals rounded down) obtained by dividing 360 by the value related to 2) above, the larger value will be M, but the smaller value may also be M, and it is preferable that the larger value be M.

[0034] The "substantially horizontal direction" in the above phrase "spraying liquid from the liquid jetting portion in a plurality of different substantially horizontal directions" may be any direction within ±5° of the horizontal direction, and the "plurality of different substantially horizontal directions" refers to spraying circulating liquid from a plurality of circulating liquid jetting ports in different directions when viewed from above. In this specification, "viewed from above" refers to when the container is viewed from above (vertically above the horizontal plane).

[0035] The liquid supply unit has a liquid supply region that supplies liquid to the liquid jetting portion from outside the container. The liquid supply region is, for example, located below the liquid jetting portion formed by the liquid jetting outlet in the liquid supply unit, and supplies a liquid containing a melt of crystal grains to the liquid jetting portion from the lower side of the container where the crystal grains have accumulated, or is located above the liquid jetting portion formed by the liquid jetting outlet, and supplies a liquid containing a melt of crystal grains to the liquid jetting portion from the upper side of the container where the crystal grains have accumulated. It is particularly preferable that after discharging a slurry containing crystal grains from the container, the liquid derived from the slurry is returned in a returning step and supplied to the liquid supply region of the liquid supply unit, but the container may not reuse the discharged slurry. Note that if the density of the crystal grains is greater than the density of the melt of crystal grains, the crystal bed moves downward, and the crystal grains accumulate at the bottom of the container. On the other hand, if the density of the crystal grains is lower than the density of the melt of the crystal grains, the direction of movement of the crystal bed will be from bottom to top, and the crystal grains will pile up at the top of the vessel.

[0036] In the method of the present invention, the number of liquid jets that is M or more is the number per liquid supply unit (one unit). The liquid jets in the liquid supply unit may be at the same or different vertical positions (heights). That is, the liquid jets may be provided in one stage, or may be provided in two or more stages and be located at two or more different heights. When the liquid jets are located at two or more different heights, the number of liquid jets is the total number. From the viewpoint of handling the crystals more evenly, the number of liquid jets is better, and is preferably M x 1.1 or more, more preferably M x 1.2 or more, even more preferably M x 1.3 or more, and particularly preferably M x 1.5 or more.

[0037] There is no particular upper limit to the number of liquid outlets, but from the viewpoint of improving the mechanical strength of the liquid supply unit and the processing accuracy during manufacturing, it is preferable that the number be M x 3 or less, and more preferably M x 2.5 or less.

[0038] In the present invention, the number of liquid jets can be specified as an absolute number. For example, from the viewpoint of handling the crystals more uniformly, the number of liquid jets is preferably 10 or more, more preferably 12 or more, even more preferably 14 or more, and particularly preferably 18 or more. There is no particular upper limit to the number of liquid jets, but it is preferably 36 or less, more preferably 30 or less.

[0039] In the method of the present invention, the number of liquid jetting ports per stage in the liquid supply unit is preferably 6 or more, more preferably 7 or more, and even more preferably 9 or more. The number of liquid jetting ports per stage is preferably 18 or less, and more preferably 15 or less.

[0040] In the method of the present invention, the liquid jetting velocity may be 0.3 m / s or more from the viewpoint of sufficiently increasing the spreading angle. From the viewpoint of further increasing the spreading angle, the liquid jetting velocity is preferably 1 m / s or more, more preferably 1.5 m / s or more, even more preferably 2 m / s or more, and particularly preferably 3 m / s or more. The upper limit of the liquid jetting velocity is not particularly limited, but is usually 20 m / s or less, and preferably 15 m / s or less.

[0041] In the method of the present invention, the amount of liquid ejected from each liquid ejection port is preferably 1.5 kg / h or more. The amount of liquid ejected is more preferably 5 kg / h or more, even more preferably 7.5 kg / h or more, even more preferably 10 kg / h or more, even more preferably 20 kg / h or more, and even more preferably 30 kg / h or more. There is no particular upper limit to the amount of liquid ejected, but it is usually 200 kg / h or less, and preferably 100 kg / h or less.

[0042] In the method of the present invention, the amount of liquid ejected per liquid supply unit is preferably 20 kg / h or more. The amount of liquid ejected is more preferably 50 kg / h or more, and even more preferably 100 kg / h or more. There is no particular upper limit to the amount of liquid ejected, but it is usually 2000 kg / h or less, and preferably 1000 kg / h or less.

[0043] In the method of the present invention, the distance between the center of a liquid jetting outlet and the center of a liquid jetting outlet adjacent to that liquid jetting outlet (center-to-center distance) is more than 1 time the diameter of the liquid jetting outlet, preferably 1.2 times or more, and more preferably 1.5 times or more, of the diameter of the liquid jetting outlet, from the viewpoints of ensuring the mechanical strength of the liquid supply unit and the processing accuracy during manufacturing. Note that the liquid jetting outlets adjacent to the liquid jetting outlet may be adjacent in the horizontal direction, in the vertical direction, or in a diagonal direction between the horizontal and vertical directions. In the method of the present invention, it is also preferable that the distance between the liquid jetting outlets be as follows: [Horizontal distance] At the inner diameter portion of the liquid supplying unit, the distance between the liquid jetting outlet and the adjacent jetting outlet (the distance between the non-perforated portions) is preferably 0.5 mm or more, more preferably 1.0 mm or more. [Vertical distance] At the outer diameter portion of the liquid supplying unit, the distance between the liquid jetting outlet and the adjacent jetting outlet (the distance between the non-perforated portions) is preferably 0.5 mm or more, more preferably 1.0 mm or more. Furthermore, from the viewpoint of proper jetting, the distance between the vertical non-perforated portion and the diameter of the liquid jet is preferably 3 mm or less, more preferably 2 mm or less, and even more preferably 1.5 mm or less. The diameter of the liquid jet is the diameter passing through the center of the liquid jet and measured in the direction between the centers of the two liquid jets, and is the diameter of the liquid jet if the liquid jet is circular. If the diameters of the two liquid jets used to determine the distance are different, the diameter of the larger liquid jet is used. The center of the liquid jet is the center of gravity when the liquid jet is likened to an object of uniform density.

[0044] In the method of the present invention, a liquid containing a melt of crystal grains is supplied into a container, and the container may be one in which a part of the liquid derived from the slurry (circulating liquid containing the melt) is reused after the slurry containing the crystal grains is discharged from the container. For example, as described above, after the slurry containing the crystal grains is discharged from the container, the crystal grains in the slurry may be melted, and the liquid derived from the slurry may be returned in a returning step and supplied to the liquid supply region of the liquid supply unit. Note that in the method of the present invention, the liquid derived from the slurry does not have to be reused.

[0045] In the method of the present invention, the vessel is preferably one in which crystal grains are deposited at the bottom or top of the vessel, and examples thereof include washing columns such as hydraulic washing columns and gravity settling washing columns, crystallization tanks that produce a slurry containing crystal grains of the compound, and aging tanks that can hold crystals of the compound in a suspended state within the vessel, with hydraulic washing columns being more preferred.

[0046] In the method of the present invention, in at least one of the liquid supply units, when viewed from above and below, it is preferable that all horizontal jet difference angles are approximately the same, where the angle formed by the jet direction of liquid jetted from a liquid jet outlet and the jet direction of liquid jetted from a liquid jet outlet adjacent to that liquid jet outlet is defined as the horizontal jet difference angle. "All horizontal jet difference angles are approximately the same" means that the difference between each horizontal jet difference angle and 360° / number of liquid jet outlets is within a range of ±25% or ±10° of 360° / number of liquid jet outlets.

[0047] From the viewpoint of handling the crystals more uniformly, the smaller the jet horizontal difference angle, the better, and all of the jet horizontal difference angles are preferably 36° or less, more preferably 30° or less. The jet horizontal difference angles may have a lower limit exceeding 0°.

[0048] In the method of the present invention, in at least one of the liquid supply units, when viewed from above and below, when the angle formed by the ejection direction of the liquid ejected from the liquid ejection outlet and the ejection direction of the liquid ejected from the liquid ejection outlet adjacent to the liquid ejection outlet is defined as the ejection horizontal difference angle, it is preferable that the difference between the maximum ejection horizontal difference angle and the minimum ejection horizontal difference angle is 10° or less, and more preferably 5° or less.

[0049] In the method of the present invention, it is preferable that the positions of the liquid jetting ports forming the liquid jetting portion are arranged on a single circle whose center is located at the liquid jetting portion when viewed from above. The phrase "having a center at the liquid jetting portion" refers to the center of gravity of the liquid jetting portion, which may be, for example, a cylindrical shape with multiple liquid jetting ports provided therein, and may also refer to a portion of the liquid jetting portion where no components are present (the interior of the cylindrical shape through which the liquid passes). Note that even when the liquid jetting ports are provided in two or more stages and located at two or more different heights, it can be said that "the positions of the liquid jetting ports forming the liquid jetting portion are arranged on a single circle whose center is located at the liquid jetting portion when viewed from above," as long as they are all located on a single circle whose center is located at the liquid jetting portion when viewed from above.

[0050] In the method of the present invention, it is more preferable that 50% or more of the liquid supply units included in the container have substantially the same horizontal jet angle difference, and it is also more preferable that substantially all of the liquid supply units in the container have substantially the same horizontal jet angle difference.

[0051] In the method of the present invention, in at least one of the liquid supply units, the liquid jetting ports are preferably located at two or more different heights when viewed from the horizontal direction. By providing the liquid jetting ports in two or more stages, the distance (shortest distance) between the liquid jetting ports, particularly in the horizontal direction, can be made more sufficient, and the mechanical strength of the liquid supply unit can be improved. There is no particular upper limit on the number of stages, but it is preferable that the number be, for example, five or less.

[0052] In the method of the present invention, the slurry is preferably discharged from at least four directions from the container at a linear velocity of 1 m / s or more. The linear velocity is more preferably 1.2 m / s or more. The upper limit of the linear velocity is not particularly limited, but it is preferably 10 m / s or less. The number of directions in which the slurry is discharged is not particularly limited, but it is preferably 10 or less. In other words, the slurry is preferably discharged from at least four slurry outlets provided in the bottom of the container, and the number of slurry outlets provided in the bottom of the container is preferably 10 or less. Furthermore, when viewed from above and below, the discharge direction of the slurry is preferably such that, when the angle formed by the discharge direction of the slurry discharged from a slurry outlet provided in the container and the discharge direction of the slurry discharged from a slurry outlet adjacent to the slurry outlet is defined as the horizontal discharge angle, all horizontal discharge angles are preferably substantially the same. The phrase "all horizontal discharge angle differences are substantially the same" means that the difference between the maximum horizontal discharge angle difference and the minimum horizontal discharge angle difference is within ±20% of the minimum horizontal discharge angle difference.

[0053] In the method of the present invention, the rate at which the slurry is withdrawn from the vessel is preferably 1,000 kg / h or more, more preferably 3,000 kg / h or more, and even more preferably 10,000 kg / h or more. The upper limit of the rate at which the slurry is withdrawn from the vessel is not particularly limited, but is usually 500,000 kg / h or less, and preferably 300,000 kg / h or less.

[0054] In the method of the present invention, the position of the slurry outlet is preferably arranged on a circle having a center on the vessel when viewed from above. The center on the vessel is, for example, the center of gravity of the vessel.

[0055] The size of the container used in the method of the present invention is not particularly limited, but for example, the inner diameter of the container is preferably 30 to 2000 mm. Furthermore, the height is preferably 1000 to 15000 mm. By using the method of the present invention, it becomes possible to handle crystal grains approximately uniformly even in industrial-scale containers. The size of the liquid supply unit in the container is not particularly limited, but for example, the inner diameter is preferably 5 to 30 mm. Furthermore, the height is preferably 10 to 300 mm. Note that the inner diameter and height of the liquid jetting portion and the liquid supply region of the liquid supply unit may differ.

[0056] The number of the liquid supply units is set to 30 to 90 cm when viewed from the top and bottom of the container. ２ In other words, it is preferable that the density of the fibers inside the container is 30 to 90 cm ２ It is preferable that the number of liquid supply units is 30 to 70 cm. ２ It is more preferable to have one point per hit, and 30 to 50 cm ２ It is even more preferable that the prize be one point.

[0057] In the method of the present invention, the thickness of the liquid jetting portion of the liquid supply unit (thickness around the liquid jetting nozzle) is preferably 0.1 to 20 mm, more preferably 0.5 to 15 mm, and even more preferably 1 to 10 mm. The material of the liquid jetting portion of the liquid supply unit (material around the liquid jetting nozzle) is not particularly limited, and metal, resin, etc. can be used. The thickness and material of the liquid supply region are also the same as those of the liquid jetting portion described above.

[0058] In the method of the present invention, a rotor blade, a scraper, or the like may be used together with the liquid supply unit as an additional mechanism for extracting crystals from the crystal bed in the vessel, but it is preferable not to use such a mechanism. The method of the present invention described above can be applied to the production method of the present invention described below, and the production method of the present invention described below can be applied to the method of the present invention.

[0059] (Method for Producing Compound) The present invention also provides a method for producing a compound using a hydraulic washing column, for example, wherein the hydraulic washing column comprises at least one circulating liquid supply unit having a circulating liquid jet port therein for jetting a circulating liquid containing a melt of crystal grains into the hydraulic washing column, the circulating liquid supply unit having a circulating liquid jetting section formed by M or more circulating liquid jetting ports calculated according to the following requirements, and a circulating liquid supply region for supplying the circulating liquid from outside the hydraulic washing column to the circulating liquid jetting section, the circulating liquid being jetted from the circulating liquid jetting section in a plurality of different substantially horizontal directions and being supplied into the hydraulic washing column through each of the circulating liquid jetting ports at a circulating liquid jetting velocity of 2 m / s or more, and the amount of liquid jetted from each circulating liquid jetting port being 10 kg / h or more. Requirements: M is the value (decimals truncated) obtained by dividing 360 by one of the following values: 1) The spread angle (°) when water is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in water. 2) The spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid jet nozzle equivalent to the above in flow analysis (numerical calculation).

[0060] In a hydraulic washing column, a slurry containing crystals of a compound is usually supplied into the hydraulic washing column, and then the crystal bed formed at the top or bottom of the hydraulic washing column is broken down, and the slurry containing the crystals is extracted and circulated as a circulating slurry or circulating liquid (for example, as shown in FIG. 1, a slurry 11a containing crystals is supplied into the hydraulic washing column 1 via a slurry supply line 11 and a slurry supply pipe 4, and the crystals accumulate at the bottom of the hydraulic washing column 1, forming a crystal bed. Although not shown, a circulating liquid supply unit is provided inside the hydraulic washing column 1, and circulating liquid is sprayed out to break up the crystal grains approximately uniformly. Then, the slurry is discharged from a slurry withdrawal port 20 at the bottom of the hydraulic washing column 1 together with the circulating liquid. The crystals are withdrawn into the slurry outlet 20, and the resulting circulating slurry containing the crystals passes through a slurry circulation line 21 connecting the slurry outlet 20 and the melting equipment 22, where the crystals contained in the circulating slurry are melted. A portion of the circulating liquid containing the molten liquid obtained by melting in the melting equipment 22 passes through a return line 24 connecting the melting equipment 22 and a return port 25 and is returned to the hydraulic washing column 1, and at least a portion of the returned circulating liquid is supplied to the circulating liquid supply region of the circulating liquid supply unit. The remainder of the returned circulating liquid may serve as a washing liquid for washing the crystals. The remaining circulating liquid passes through a product withdrawal line 23 branching off from the return line 24 and is withdrawn from the purification apparatus as product 23a.

[0061] The following description first explains the supply of circulating liquid from the circulating liquid supply unit to the hydraulic washing column to break up the crystal bed approximately uniformly when withdrawing the circulating slurry containing the crystals. Then, other steps, such as the step of supplying the slurry containing the compound crystals to the hydraulic washing column, the melting step, and the return step, are sequentially described. In a continuous purification process, the steps of supplying the slurry containing the compound crystals to the hydraulic washing column, the step of supplying the circulating liquid from the circulating liquid supply unit to the hydraulic washing column and withdrawing the circulating slurry containing the crystals, the melting step, and the return step are performed in this order on the target of purification. However, when viewed as a whole purification apparatus, each step is performed simultaneously. In this specification, the term "compound" refers to the compound obtained by the production method of the present invention, and does not refer to the raw materials, by-products, or solvents used in the production method of the present invention. The term "compound" can be interchangeably referred to as the "target compound" or the "target product." In this specification, the term "impurities" refers to components other than the "compound," such as raw materials, by-products, and solvents.

[0062] <Supply of circulating liquid from circulating liquid supply unit to hydraulic cleaning column> The circulating liquid supply unit has a circulating liquid jetting portion formed by M or more circulating liquid jetting ports calculated according to the following requirements: Requirement: M is the value (decimals omitted) obtained by dividing 360 by one of the following values: 1) The spread angle (°) when water is jetted from a single liquid jetting port equivalent to the above at the same speed in water; 2) The spread angle (°) when a liquid with equivalent physical properties is jetted from a single liquid jetting port equivalent to the above at the same speed in flow analysis (numerical calculation).

[0063] The manufacturing method of the present invention is similar to the method of discharging a slurry containing crystal grains from a vessel of the present invention, except that the amount of liquid ejected from each circulating liquid ejection port is specified, the vessel is specified as a hydraulic washing column, and the liquid containing the molten liquid is specified as a circulating liquid containing the molten liquid. For example, the "single liquid ejection port equivalent to the above" in the manufacturing method of the present invention is the same as the "single liquid ejection port equivalent to the above" in the above-described method of discharging a slurry containing crystal grains from a vessel of the present invention. Furthermore, the "same speed" and "liquid of equivalent physical properties" in the manufacturing method of the present invention are the same as the "same speed" and "liquid of equivalent physical properties" in the above-described method of discharging a slurry containing crystal grains from a vessel of the present invention. Other terms are also the same as those described above unless explicitly specified. Note that the manufacturing method of the present invention, in which the amount of liquid ejected from each circulating liquid ejection port is specified, can substantially uniformly break down the crystal bed at the bottom or top of the hydraulic washing column.

[0064] The circulating liquid supply unit has a circulating liquid supply region that supplies circulating liquid to the circulating liquid jetting portion from outside the hydraulic cleaning column. The circulating liquid supply region is, for example, located below the circulating liquid jetting portion formed by the circulating liquid jetting outlet in the circulating liquid supply unit and supplies a circulating liquid containing a melt of crystal grains to the circulating liquid jetting portion from the lower side of the hydraulic cleaning column where the crystal grains have accumulated, or is located above the circulating liquid jetting portion formed by the circulating liquid jetting outlet and supplies a circulating liquid containing a melt of crystal grains to the circulating liquid jetting portion from the upper side of the hydraulic cleaning column where the crystal grains have accumulated. In the production method of the present invention, for example, after the slurry containing crystal grains is extracted from the hydraulic cleaning column, it is preferable that the circulating liquid containing the melt obtained by melting the crystal grains in the slurry is returned in a returning step, supplied to the circulating liquid supply region of the circulating liquid supply unit, and supplied from the circulating liquid supply region to the circulating liquid jetting portion. Here, the circulating fluid supply region is connected to the return port of the hydraulic washing column at the bottom surface of the circulating fluid supply unit.

[0065] In the production method of the present invention, the circulating liquid jetting velocity may be 0.3 m / s or more. From the viewpoint of increasing the spreading angle, the circulating liquid jetting velocity is preferably 1 m / s or more, more preferably 1.5 m / s or more, even more preferably 2 m / s or more, and particularly preferably 3 m / s or more. The upper limit of the circulating liquid jetting velocity is not particularly limited, but is usually 20 m / s or less, and preferably 15 m / s or less.

[0066] In the production method of the present invention, the amount of liquid ejected from each circulating liquid ejection port may be 1.5 kg / h or more. This allows the crystal bed to be broken down approximately uniformly. The amount of liquid ejected is preferably 5 kg / h or more, more preferably 7.5 kg / h or more, even more preferably 10 kg / h or more, even more preferably 20 kg / h or more, and particularly preferably 30 kg / h or more. There is no particular upper limit for the amount of liquid ejected, but it is usually 200 kg / h or less, and preferably 100 kg / h or less.

[0067] In the production method of the present invention, the amount of sprayed liquid per circulating liquid supply unit is preferably 20 kg / h or more. The amount of sprayed liquid is preferably 50 kg / h or more, and more preferably 100 kg / h or more. The upper limit of the amount of sprayed liquid is not particularly limited, but is usually 2000 kg / h or less, and preferably 1000 kg / h or less. In the production method of the present invention, if the diameter of the hydraulic washing column is large, the number of circulating liquid supply units increases, and the amount of sprayed liquid increases. For this reason, it is preferable to apply the production method of the present invention to bulk chemicals (chemical products that are mass-produced) such as (meth)acrylic acid.

[0068] In the production method of the present invention, the number of the circulating liquid supply units is set to 30 to 90 cm when viewed from the top and bottom of the hydraulic washing column. ２ In other words, the number density inside the hydraulic washing column is preferably 30 to 90 cm ２It is preferable that the number of circulating liquid supply units is arranged so as to correspond to the hydraulic washing column or a component (e.g., a filter) provided in the hydraulic washing column. This allows the crystal grains to be handled more uniformly, and more uniform washing is possible. The number of the circulating liquid supply units is 30 to 70 cm ２ It is more preferable to have one point per hit, and 30 to 50 cm ２ It is even more preferable that the prize be one point.

[0069] In the production method of the present invention, the temperature of the circulating fluid is preferably at least the melting point of the compound + 1° C. Although there is no particular upper limit to the temperature of the circulating fluid, it is usually preferably at most the melting point of the compound + 20° C., and more preferably at most the melting point of the compound + 15° C.

[0070] For example, when the compound is acrylic acid, the temperature of the circulating liquid is preferably 14° C. or higher. In this case, the temperature of the circulating liquid is usually 33° C. or lower, and preferably 28° C. or lower.

[0071] In the production method of the present invention, the compound is preferably an organic compound having a higher solid density than the liquid density. When the compound is an organic compound having a higher solid density than the liquid density, the crystal bed moves downward from the top, and the crystal grains accumulate at the bottom.

[0072] In the production method of the present invention, the compound preferably has a melting point of 0 to 80°C, more preferably 1 to 50°C, even more preferably 3 to 40°C, and particularly preferably 5 to 20°C. Furthermore, the compound having the above melting point is preferably an easily polymerizable compound having a reactive double bond. Among these, in the production method of the present invention, the compound is more preferably an unsaturated carboxylic acid, even more preferably (meth)acrylic acid, and particularly preferably acrylic acid. In this specification, (meth)acrylic acid refers to acrylic acid and / or methacrylic acid. Even when the compound is an easily polymerizable compound having a reactive double bond, such as (meth)acrylic acid, the production method of the present invention can be preferably applied.

[0073] In the production method of the present invention, the hydraulic washing column preferably has a heated outer wall surface, which can prevent freezing and enable stable production of the compound.

[0074] The hydraulic washing column preferably has an outer wall surface heated by a heat medium. The heat medium is not particularly limited, and any liquid or gas can be used, including water, antifreeze, methanol water (methanol aqueous solution), gas, etc. The heat medium may be appropriately selected taking into account the freezing point of the compound to be purified. The flow rate of the heat medium may be appropriately set so that the difference between the inlet and outlet temperatures of the heat medium is less than 5°C, preferably less than 3°C, and more preferably less than 1°C.

[0075] In the production method of the present invention, the outer wall surface of the hydraulic washing column is preferably heated with a heat medium at least 3°C ​​higher than the melting point of the compound. As described above, the temperature of the heat medium is preferably 3°C or higher than the melting point of the compound, more preferably 5°C or higher, and even more preferably 7°C or higher. The temperature of the heat medium is preferably 30°C or lower, more preferably 20°C or lower, than the melting point of the compound. In other words, the temperature of the heat medium is usually higher than the melting point of the compound, but the difference is preferably 30°C or lower, more preferably 20°C or lower. The melting point of the compound refers to the melting point of the target compound, and is preferably 0 to 80°C, more preferably 1 to 50°C, even more preferably 3 to 40°C, and particularly preferably 5 to 20°C. The heating may be performed by heating a portion of the hydraulic washing column with a heat medium or the like, but is preferably performed by heating substantially the entire hydraulic washing column (jacket type). In the case of a jacketed system in which the heat medium is a liquid, it is preferable to supply the heat medium from below the jacket, and in this case, the temperature of the heat medium is preferably the inlet temperature. The heat medium may also be supplied from above the jacket, and in this case, the temperature of the heat medium is preferably the outlet temperature. The interior of the hydraulic washing column is basically operated under pressure (preferably in the range of 0.05 to 1.0 MPa).

[0076] <Step of Supplying Slurry Containing Compound Crystals to a Hydraulic Washing Column> The production method of the present invention preferably includes a step of supplying a slurry containing compound crystals to a hydraulic washing column. The slurry containing the crystals is a suspension of compound crystals and mother liquor; in other words, the liquid portion of the slurry containing compound crystals supplied to the hydraulic washing column is the mother liquor. As described below, the slurry containing the crystals can be obtained by generating crystals in a compound-containing solution (e.g., an aqueous (meth)acrylic acid solution or a crude (meth)acrylic acid solution), and the compound-containing solution may be prepared in-house or procured from another source. The compound-containing solution referred to here also includes crude compounds.

[0077] In the slurry containing crystals supplied to the hydraulic washing column, the mass proportion of crystals is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The mass proportion of crystals is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 20% by mass or less. In this specification, when simply referring to "slurry containing crystals supplied to the hydraulic washing column", the slurry containing crystals supplied to the hydraulic washing column refers to the slurry containing crystals immediately before being supplied to the hydraulic washing column.

[0078] The crystal-containing slurry supplied to the hydraulic washing column preferably contains the compound in its mother liquor. Examples of the mother liquor include the compound and an aqueous solution of the compound. The mother liquor typically contains impurities other than the compound and water. In the method for producing a compound of the present invention, the crystal-containing slurry supplied to the hydraulic washing column preferably has a purity (mass proportion) of the compound in the mother liquor of 99% by mass or less. This enhances the effects of the present invention. The mass proportion of the compound in the mother liquor is more preferably 98% by mass or less. The mass proportion of the compound in the mother liquor is preferably 85% by mass or more, more preferably 88% by mass or more, and even more preferably 90% by mass or more.

[0079] The mass proportion of water in the mother liquor is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, and is preferably 8% by mass or less, more preferably 6% by mass or less, and even more preferably 4% by mass or less.

[0080] In order to ensure that the effects of the present invention are significant, the mass proportion of impurities other than the compounds and water in the mother liquor is preferably 0.1% by mass or more, more preferably 0.4% by mass or more, and even more preferably 0.8% by mass or more. The mass proportion of impurities other than the compounds and water in the mother liquor is preferably 8% by mass or less, more preferably 6% by mass or less, and even more preferably 4% by mass or less.

[0081] When the compound is (meth)acrylic acid, impurities other than the compound and water include, for example, acetic acid and furfural. In this case, the mass proportion of acetic acid in the mother liquor is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.7% by mass or more, from the viewpoint of ensuring a significant effect of the present invention. The mass proportion of acetic acid in the mother liquor is preferably 8% by mass or less, more preferably 6% by mass or less, and even more preferably 4% by mass or less.

[0082] When the compound is (meth)acrylic acid, the mass proportion of furfural in the mother liquor is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of achieving remarkable effects of the present invention. The mass proportion of furfural in the mother liquor is preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less.

[0083] In the feeding step, the feeding rate of the crystal-containing slurry is not particularly limited. In an industrial-scale hydraulic washing column, the feeding rate is, for example, 0.2 × 10 ３ ~4.0 x 10 ５ kg / h.

[0084] In the supplying step, the supply temperature of the crystal-containing slurry can be set appropriately depending on the melting point of the compound, and can be adjusted appropriately within the range of, for example, 0 to 80° C. For example, when the compound is (meth)acrylic acid, the supply temperature of the crystal-containing slurry is preferably 5 to 13° C., and more preferably 6 to 12° C. The supply temperature of the crystal-containing slurry is the temperature of the mother liquor in the crystal-containing slurry immediately before it is supplied to the hydraulic washing column.

[0085] <Melting step> The production method of the present invention preferably includes a step of withdrawing a circulating slurry containing crystal grains from a hydraulic washing column and melting the crystal grains contained in the withdrawn circulating slurry. The crystal grains originate from a crystal bed formed in the lower or upper part of the hydraulic washing column. The crystal grains can be suitably withdrawn by breaking up the crystal bed using the circulating liquid supply unit described above. When withdrawing the crystals, the circulating liquid is usually withdrawn together, and the crystals are withdrawn as a circulating slurry containing the crystals and subjected to the melting step.

[0086] For example, in the circulating slurry containing the crystals extracted from the hydraulic washing column, the mass proportion of the crystals is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, and particularly preferably 5% by mass or more. The mass proportion of the crystals is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and particularly preferably 10% by mass or less. In this specification, the circulating slurry or crystals containing the crystals extracted from the hydraulic washing column refers to the circulating slurry or crystals containing the crystals immediately after being extracted from the hydraulic washing column, for example, the circulating slurry or crystals containing the crystals in the slurry circulation line connecting the slurry outlet and the melting equipment.

[0087] The withdrawal rate of the circulating slurry containing crystals withdrawn from the hydraulic wash column is not particularly limited. In an industrial-scale hydraulic wash column, the withdrawal rate is, for example, 2 × 10 ３ ~5 x 10 ５ As described above, the hydraulic washing column may be provided with a plurality of slurry withdrawal ports and a plurality of slurry circulation lines.

[0088] The extracted crystals can be melted using a heater. Examples of heaters include those with a structure that efficiently transfers heat to the crystal-containing slurry, such as a vertical multi-tube heat exchanger, a horizontal multi-tube heat exchanger, a double-tube heat exchanger, a spiral heat exchanger, a plate heat exchanger, and an electric heater. The heater is preferably installed in the melt loop, and is of a forced circulation type in which the circulating slurry (a circulating liquid after melting) is circulated by a pump installed in the melt loop.

[0089] The heating temperature in the melting step may be appropriately set depending on the melting point of the compound, and may be appropriately adjusted, for example, within a range of 10 to 100°C. For example, when the compound is (meth)acrylic acid, the heating temperature in the melting step is preferably 15°C or higher. Furthermore, the heating temperature is preferably 50°C or lower, more preferably 40°C or lower. When a heat medium is supplied to the melting equipment for heating, the heating temperature in the melting step is the temperature of the heat medium. Furthermore, the temperature of the circulating liquid containing the molten liquid at the outlet of the melting step (melting equipment) is preferably set to a temperature 1 to 20°C higher, more preferably 1 to 15°C higher, than the melting point of the circulating liquid containing the molten liquid obtained in the melting step (e.g., a circulating liquid containing the molten liquid obtained by passing through a heat exchanger or the like and melting the crystals in the slurry during this process). The melting time in the melting step may be appropriately determined so that the crystals are sufficiently melted.

[0090] <Returning Step> The production method of the present invention preferably includes a step of returning a part of the circulating liquid containing the melt obtained in the melting step to the hydraulic washing column. Note that the melt is contained in the circulating liquid and therefore cannot be separated as a melt.

[0091] The circulating liquid contains the molten liquid obtained in the melting step. That is, the crystals in the withdrawn circulating slurry are melted to form a molten liquid, and the suspended circulating slurry becomes an unsuspended circulating liquid. The circulating liquid is withdrawn from the hydraulic washing column as a circulating slurry containing crystals, and then a portion of the circulating liquid containing the molten liquid obtained in the melting step is returned to the hydraulic washing column, so that the circulating liquid passes through the hydraulic washing column and circulates; in other words, it flows through a circulation path that passes through the hydraulic washing column. In this specification, the liquid component of the circulating slurry flowing through the circulation path is also referred to as the circulating liquid.

[0092] The molten liquid obtained in the melting step refers to the liquid obtained by melting the crystals contained in the circulating slurry extracted from the hydraulic washing column, and does not include the circulating liquid (liquid component) contained in the circulating slurry. Here, the circulating slurry is a suspension of compound crystals and the circulating liquid that flows through the circulating path.

[0093] The circulation path is a path that circulates through the hydraulic washing column. Specific examples include a slurry circulation line connecting the slurry outlet of the hydraulic washing column to the melting equipment and a return line connecting the melting equipment to the return port of the hydraulic washing column. A circulating liquid containing a circulating slurry or a melt liquid circulates through the circulation path. In this specification, this circulation path is also referred to as a melt loop. The portion of the circulation path through which the circulating slurry flows is the portion from when the crystals from the hydraulic washing column are introduced into the circulating liquid to form a circulating slurry, until the crystals contained in the circulating slurry are melted. For example, in the melt loop described above, the circulating liquid returned from the return port 25 at the bottom of the hydraulic washing column is sprayed from the circulating liquid spray port of the circulating liquid supply unit and supplied into the hydraulic washing column. The circulating liquid mixes with the crystals in the hydraulic washing column to form a circulating slurry, which then flows through the path (slurry circulation line 21) between the slurry outlet 20 and the melting equipment 22. It is acceptable that a portion of the returned circulating liquid is not introduced into the circulating liquid supply unit, but serves as a washing liquid in a countercurrent flow to the direction of movement of the crystals (bed). The washing liquid is a portion of the circulating liquid returned to the hydraulic washing column, which is returned to the hydraulic washing column and then supplied to the circulating liquid supply unit, and is not recirculated through the circulation path, but flows, for example, through the gaps between the crystals in the crystal bed of the hydraulic washing column in a countercurrent flow (preferably upward) to the direction of movement of the crystals, thereby washing the crystals in the hydraulic washing column.

[0094] The product is extracted and removed from the circulating liquid flowing through the circulation path. Meanwhile, crystals are extracted from the hydraulic washing column and introduced into the circulating liquid flowing through the circulation path. The amount of crystals removed from the circulation path and the amount of crystals introduced into the circulation path are balanced during continuous operation, and the sum of the amount of product extracted and the amount of washing liquid is equal to the amount of crystals extracted from the hydraulic washing column, i.e., the amount of melt obtained in the melting step.

[0095] As described above, the returning step involves returning a portion of the circulating liquid containing the melt obtained in the melting step to the hydraulic washing column. When using a portion of the returned circulating liquid as a washing liquid, the flow of the washing liquid is preferably returned in a countercurrent to the direction of movement of the crystals (bed), and this may be determined appropriately depending on the specific gravities of the washing liquid and the crystals. For example, when the specific gravity of the crystals is greater than that of the mother liquor, the circulating liquid is preferably returned upward. Here, "upward" preferably means a direction substantially perpendicular to a horizontal plane. This allows the crystals to be washed efficiently. In the returning step, the product withdrawal rate at which the product is withdrawn is 5 kg / h to 4.0 x 10 in an industrial-scale hydraulic washing column. ４ kg / h.

[0096] In the production method of the present invention, a mechanism (control mechanism) for controlling the amount of return of the circulating liquid can be appropriately used. Examples of the control mechanism include a valve attached to the line in the return mechanism (branch path). In the production method of the present invention, by using the control mechanism for the amount of return of the circulating liquid, the amount of return of the circulating liquid can be adjusted, and as necessary, impurities can be separated efficiently, allowing the product to be obtained efficiently.

[0097] The control mechanism may be a mechanism that directly controls the amount of circulating fluid returned, or a mechanism that indirectly controls the amount. When the control mechanism directly controls the amount of circulating fluid returned, an example of the control mechanism is a valve (not shown) attached to the return line 24 shown in FIG. 1 . When the control mechanism indirectly controls the amount of circulating fluid returned, an example of the control mechanism is a valve (not shown) attached to the product withdrawal line 23 connected to the product withdrawal port (not shown). By adjusting the valve attached to the product withdrawal line 23, the amount of circulating fluid returned in the return line 24 can be controlled. Valves may be installed in both the product withdrawal line 23 and the return line 24. For example, the valves can be controlled depending on the flow rates in the product withdrawal line 23 and the return line 24. Alternatively, a multi-point thermometer may be installed in the hydraulic washing column to control the valve depending on the internal temperature.

[0098] <Step of withdrawing mother liquor> The production method of the present invention may further include a step of filtering the crystal-containing slurry in the hydraulic washing column using a filter and withdrawing the mother liquor using a pipe connected to the filter. The withdrawn mother liquor can be recycled and reused. For example, by reusing the withdrawn mother liquor as at least a part of the crystal-containing slurry to be supplied to the hydraulic washing column, the quality of the compound can be further improved. Note that when the specific gravity of the crystals is greater than that of the mother liquor, the mother liquor contained in the slurry supplied in the supply step flows downward from above, collides with the washing liquid flowing upward from below, is pushed back, and is withdrawn through the filter.

[0099] The mother liquor extracted in the step of extracting the mother liquor usually contains the compound. Examples of the mother liquor include a liquid in which the compound is dissolved and an aqueous solution of the compound. The mother liquor usually contains impurities other than the compound and water. The mother liquor extracted in the step of extracting the mother liquor refers to the mother liquor immediately after passing through a filter in the step of extracting the mother liquor.

[0100] The step of extracting the mother liquor can be carried out appropriately using a pump or the like.

[0101] In the production method of the present invention, when the above filter and a pipe connected to the filter are used, one of the preferred embodiments of the production method of the present invention is to place a circulating liquid supply unit below the filter.

[0102] <Step of Obtaining Slurry Containing Crystals> The manufacturing method of the present invention preferably further includes a step of obtaining a slurry containing crystals of the compound from the compound-containing solution. The compound-containing solution can be obtained by collecting the gas of the compound, which is the reaction product obtained in the chemical reactor, for example, in an absorption tower, and also includes crude compounds obtained by purifying the collected gas. The compound-containing solution is not limited to one obtained by self-synthesis, but may also be one procured from another source. The compound-containing solution can be cooled, for example, to obtain a slurry containing crystals of the compound.

[0103] The compound-containing solution contains impurities other than the compound and water. In the production method of the present invention, the compound-containing solution is preferably an aqueous (meth)acrylic acid solution or a crude (meth)acrylic acid solution. The aqueous (meth)acrylic acid solution refers to a solution in which (meth)acrylic acid is dissolved in water. The crude (meth)acrylic acid solution refers to a solution composed of (meth)acrylic acid and containing impurities such as by-products produced during the production of (meth)acrylic acid. Examples of the impurities include acids such as propionic acid, acetic acid, maleic acid, benzoic acid, and acrylic acid dimer; aldehydes such as acrolein, furfural, formaldehyde, and glyoxal; methyl isobutyl ketone, toluene, protoanemonin, and acetone. The production method of the present invention allows for sufficient removal of impurities contained in the compound-containing solution.

[0104] <Step of Obtaining a Compound-Containing Solution> The production method of the present invention preferably further includes a step of obtaining a compound-containing solution from raw materials.

[0105] The step of obtaining the compound-containing solution is not particularly limited as long as a compound-containing solution can be obtained. However, when the compound is (meth)acrylic acid, the step of synthesizing acrylic acid and the step of collecting acrylic acid described in JP 2007-182437 A (Patent Document 1) can be suitably carried out. In the method for producing a compound of the present invention, the raw material is preferably at least one selected from the group consisting of propane, propylene, acrolein, isobutene, methacrolein, acetic acid, lactic acid, isopropanol, 1,3-propanediol, glycerol, and 3-hydroxypropionic acid. Furthermore, the (meth)acrylic acid and / or the raw material may be derived from renewable raw materials to produce bio-based (meth)acrylic acid.

[0106] In the process of obtaining the compound-containing solution, impurities such as by-products are generally produced. For example, when the compound is (meth)acrylic acid, impurities that are produced include water, acids such as propionic acid, acetic acid, maleic acid, benzoic acid, and acrylic acid dimer, aldehydes such as acrolein, furfural, formaldehyde, and glyoxal, methyl isobutyl ketone, toluene, protoanemonin, and acetone. However, by using a hydraulic washing column or the like according to the production method of the present invention, the impurities can be separated with excellent efficiency, and the product can be obtained efficiently.

[0107] The size of the hydraulic washing column used in the production method of the present invention is not particularly limited, but for example, the inner diameter of the column (crystallization chamber) is preferably 30 to 2000 mm. Furthermore, the height is preferably 1000 to 15000 mm. By using the production method of the present invention, it becomes possible to break down the crystal bed approximately uniformly, even in an industrial-scale hydraulic washing column. The size of the circulating liquid supply unit in the hydraulic washing column is not particularly limited, but for example, the inner diameter is preferably 5 to 30 mm. Furthermore, the height is preferably 10 to 300 mm.

[0108] The size of the filter used to filter the crystal-containing slurry in the hydraulic washing column is not particularly limited, but for example, its inner diameter is preferably 10 to 30 mm. Furthermore, its height is preferably 20 to 300 mm. Examples of the filter include those having a large number of circular holes, slits (notches), or rectangular holes. Furthermore, the shape is not particularly limited, but examples include shapes similar to pipes, such as cylindrical shapes. When the filter has circular hole shapes, the diameter may be adjusted appropriately depending on the size of the crystals, but is preferably 50 to 500 μm, for example. Furthermore, the number of holes is not particularly limited, and may be adjusted, for example, depending on the pressure loss, etc.

[0109] The pipe connected to the filter for withdrawing the mother liquor is usually located above the filter. The pipe connected to the filter for withdrawing the mother liquor is not particularly limited, but for example, in an industrial-scale hydraulic wash column, the cross-sectional area of ​​the hydraulic wash column is 30 to 90 cm. ２ It is preferable that one filter is connected to one pipe.

[0110] In the production method of the present invention, a rotor blade or a scraper may be further used as a mechanism for extracting crystals from the crystal bed in the hydraulic washing column, but it is preferable not to use such a mechanism. In particular, when the compound is an easily polymerizable compound having a reactive double bond, it is more preferable not to use such a mechanism. The reason for this is that, as mentioned above, in the production method of the present invention, the compound is preferably an easily polymerizable compound having a reactive double bond, such as (meth)acrylic acid, but when these compounds are used, for example, when a scraper is used, there is a concern that polymerization will occur at the seal due to sliding heat, resulting in leakage.

[0111] The production method of the present invention preferably further comprises a step of heating the outer wall surface of the hydraulic washing column. This prevents freezing and enables stable use of the purification apparatus. The step of heating the outer wall surface of the hydraulic washing column is not particularly limited, and a heat transfer medium, steam tracing, electric tracing, or a known heater for adjusting the ambient temperature of the column can be used. For example, a portion of the hydraulic washing column can be heated using a heat transfer medium, or substantially the entire hydraulic washing column can be heated (jacket type).

[0112] The number of pipes that supply the crystal-containing slurry to the hydraulic washing column and the supply nozzles (slurry supply ports) that may be connected to the ends of the pipes are not particularly limited, and may be one or more (FIG. 1 shows a case where there is one pipe that supplies the crystal-containing slurry to the hydraulic washing column). The supply nozzle may have a dispersion mechanism at its end that disperses the slurry. The hydraulic washing column may further include a dispersion chamber or a central displacement body (see JP-A-2005-509010).

[0113] The production method of the present invention may further include a dummy pipe connected to a filter that filters the crystal-containing slurry in the hydraulic washing column. The dummy pipe is usually located below the filter. The circulating liquid supply unit is preferably located below the dummy pipe, and particularly preferably directly below it.

[0114] The hydraulic cleaning column may be provided with instrumentation such as a thermometer (multipoint type, etc.), a pressure gauge, an interface meter (optical type, etc.) in the main body or around the column. The hydraulic cleaning column itself may be placed in a temperature-controlled casing (generally inside a building, etc.).

[0115] (Method of Using a Hydraulic Wash Column) The present invention also relates to a method of using a hydraulic wash column, comprising the step of purifying a compound using the hydraulic wash column of the present invention.

[0116] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples, and can be practiced with appropriate modifications within the scope of the above and below-described aims, all of which are included in the technical scope of the present invention. Unless otherwise specified below, "%" means "% by mass" and "parts" means "parts by mass".

[0117] (Example 1) According to the method described in WO 2010 / 032665, propylene was subjected to catalytic gas phase oxidation to obtain an acrylic acid-containing gas. Thereafter, the obtained acrylic acid-containing gas was introduced into an absorption tower and collected with water, thereby obtaining an aqueous acrylic acid solution.

[0118] Next, the aqueous acrylic acid solution was supplied to a crystallization tank. The crystallization tank was equipped with a jacket, and the content of the crystallization tank could be indirectly cooled by supplying a refrigerant to the jacket. The aqueous acrylic acid solution was cooled in the crystallization tank and adhered to the inner surface of the crystallization tank as crystals. These were scraped off with a scraper provided inside the crystallization tank to form a slurry containing the crystals (supply slurry).

[0119] 1 and 2 were prepared as a purification apparatus for obtaining a product from the slurry containing the crystals. The specifications of the purification apparatus were as follows: Hydraulic washing column 1: 4 slurry withdrawal ports 20 Filter 2: Material: PEEK, filter section structure: 250 μm diameter circular holes Mother liquor withdrawal pipe 3: Material: SUS Melt loop line (slurry withdrawal port 20, slurry circulation line 21, product withdrawal line 23, return line 24, return port 25): Flow control valve installed in product withdrawal line 23 (not shown) Melting equipment 22: Heat exchanger Overall apparatus: Jacket structure (not shown) Circulating liquid supply unit: 12 openings per unit (all horizontal jet angle difference approximately the same), 1 opening stage, number density 45 cm ２ / Book

[0120] Using the above-mentioned purification apparatus, acrylic acid was purified from the slurry containing the crystals (feed slurry). A slurry 11a containing acrylic acid crystals was supplied to the hydraulic washing column 1 via the slurry supply pipe 4 at a slurry concentration (acrylic acid crystal concentration) of 10 mass%, a slurry temperature of 9.3°C, and a supply rate of 4.63 t / h. The operating internal pressure of the hydraulic washing column 1 was set to 0.4 MPa, and a heat transfer medium was introduced into the jacket (not shown) so that the temperature at the heat transfer medium inlet was 25°C.

[0121] 2 were installed at approximately equal intervals at the bottom of the hydraulic washing column 1. In Example 1, the circulating liquid supply unit ejected a liquid at a rate of 36 kg / h per opening (each round hole), and the total ejected liquid rate from the circulating liquid supply unit was 3.0 t / h, and the melt was supplied into the hydraulic washing column 1 at a rate of 3 m / s.

[0122] Next, the slurry containing acrylic acid crystals was withdrawn at a linear velocity of 1.2 m / s from the slurry withdrawal outlets 20 (four locations) provided at the bottom of the hydraulic washing column 1 and sent to a melting facility 22 (heat exchanger) at a flow rate of 3.23 t / h. The slurry containing acrylic acid crystals was melted in the heat exchanger while controlling the heat medium temperature so that the liquid temperature at the outlet of the heat exchanger would be 15° C., to give a molten liquid.

[0123] A part of the melt was withdrawn as a product from the product withdrawal line 23 at a flow rate of 0.23 t / h. The remainder was returned to the hydraulic washing column 1 from the return port 25 via the return line 24.

[0124] By the above operation, the crystal bed formed in the hydraulic washing column 1 could be broken down almost uniformly, and a product could be obtained.

[0125] Example 2 The same operations as in Example 1 were performed, except that the number of openings in the circulating liquid supply unit was changed to 20 per unit, the number of stages was changed to two (see FIG. 2 ), the amount of liquid sprayed from the entire circulating liquid supply unit was changed to 5.0 t / h (5.23 t / h as the flow rate when sent to the melting equipment 22), and the linear velocity when the slurry was withdrawn from the slurry withdrawal port 20 of the hydraulic washing column 1 was changed to 2.0 m / s.

[0126] As a result, the crystal bed formed in the hydraulic washing column 1 could be broken down almost uniformly, and a product could be obtained.

[0127] Comparative Example 1 The same operations as in Example 1 were performed, except that the number of openings of the circulating liquid supply unit was 8 per unit, the spray speed from the circulating liquid supply unit was 6 m / s, the amount of sprayed liquid per opening (each round hole) of the circulating liquid supply unit was 71 kg / h / opening, the amount of sprayed liquid from the entire circulating liquid supply unit was 4.0 t / h (4.23 t / h as the flow rate when sent to the melting equipment 22), and the linear velocity when the slurry was withdrawn from the slurry withdrawal port 20 of the hydraulic washing column 1 was 1.6 m / s.

[0128] As a result, although the crystal bed formed in the hydraulic washing column 1 could be broken down, the number of nozzles was insufficient, so the crystal bed did not break down approximately evenly, and a product of the required quality could not be obtained.

[0129] Comparative Example 2 The same operations as in Example 1 were performed, except that the number of openings in the circulating liquid supply unit was changed to 12 per unit, the number of stages was changed to two (see FIG. 2 ), the spray speed from the circulating liquid supply unit was changed to 1.5 m / s, the spray amount per opening (each round hole) of the circulating liquid supply unit was changed to 18 kg / h / opening, the spray amount of the entire circulating liquid supply unit was changed to 1.5 t / h (1.73 t / h as the flow rate when sent to the melting equipment 22), and the linear velocity when the slurry was withdrawn from the slurry withdrawal port 20 of the hydraulic washing column 1 was changed to 0.6 m / s.

[0130] As a result, although the crystal bed formed in the hydraulic washing column 1 could be broken down, the ejection speed was insufficient and the expansion angle was insufficient, so the crystal bed did not break down approximately evenly, and a product of the required quality could not be obtained.

[0131] Reference Example 1 The same operations as in Example 1 were performed, except that the number of openings in the circulating liquid supply unit was 20 per unit, the number of stages was 2 (see FIG. 2 ), the spray speed from the circulating liquid supply unit was 1.5 m / s, the amount of sprayed liquid per opening (each round hole) of the circulating liquid supply unit was 4 kg / h / opening, the amount of sprayed liquid from the entire circulating liquid supply unit was 0.62 t / h (0.85 t / h as the flow rate when sent to the melting equipment 22), and the linear velocity when the slurry was withdrawn from the slurry withdrawal port 20 of the hydraulic washing column 1 was 0.3 m / s.

[0132] As a result, by adjusting the amount of slurry supplied and / or the slurry concentration, it was possible to break down the crystal bed almost uniformly, and a high-quality product was obtained.

[0133] Comparative Example 3 The same operations as in Example 1 were performed, except that the number of openings of the circulating liquid supply unit was 8 per unit, the spray speed from the circulating liquid supply unit was 1.5 m / s, the amount of sprayed liquid per opening (each round hole) of the circulating liquid supply unit was 4 kg / h / opening, the amount of sprayed liquid from the entire circulating liquid supply unit was 0.25 t / h (0.48 t / h as the flow rate when sent to the melting equipment 22), and the linear velocity when the slurry was withdrawn from the slurry withdrawal port 20 of the hydraulic washing column 1 was 0.1 m / s.

[0134] As a result, the crystal bed formed in the hydraulic washing column 1 could not be broken down, and the purification apparatus could not be operated.

[0135] Example 3 In Example 2, the slurry supply rate was set to 10.4 t / h, and the number density of the circulating liquid supply units was set to 101 cm ２ The same operations as in Example 2 were carried out, except that the spray velocity from the circulating liquid supply unit was changed to 6 m / s, the spray liquid rate per opening (one round hole) of the circulating liquid supply unit was changed to 71 kg / h / unit, the spray liquid rate from the entire circulating liquid supply unit was changed to 10.0 t / h, the product rate was changed to 0.52 t / h, and the linear velocity when the slurry was withdrawn from the slurry withdrawal port 20 of the hydraulic washing column 1 was changed to 1.4 m / s.

[0136] As a result, the crystal bed formed in the hydraulic washing column 1 could be broken down almost uniformly, and the product could be obtained. However, when the number density of the circulating liquid supply unit was 101 cm ２ / Since the gap was somewhat narrow, the ejection speed was adjusted to increase the coverage area of ​​the ejected liquid.

[0137] Example 4 In Example 2, the slurry supply rate was set to 1.16 t / h, and the number density of the circulating liquid supply units was set to 11 cm ２ The same operations as in Example 2 were carried out, except that the spray velocity from the circulating liquid supply unit was changed to 2 m / s, the spray rate per opening (one round hole) of the circulating liquid supply unit was changed to 24 kg / h / unit, the spray rate of the entire circulating liquid supply unit was changed to 3.3 t / h, the product rate was changed to 0.06 t / h, and the linear velocity when the slurry was withdrawn from the slurry withdrawal port 20 of the hydraulic washing column 1 was changed to 0.7 m / s.

[0138] As a result, the crystal bed formed in the hydraulic washing column 1 could be broken down almost uniformly, and the product could be obtained. However, when the number density of the circulating liquid supply unit was 11 cm ２ / Since the nozzle was somewhat dense, the ejection speed was adjusted to further avoid interference between the ejected liquid.

[0139] Example 5 The same operations as in Example 2 were performed, except that the spray velocity from the circulating liquid supply unit was changed to 2 m / s, the spray liquid rate per opening (each round hole) of the circulating liquid supply unit was changed to 24 kg / h / unit, the spray liquid rate from the entire circulating liquid supply unit was changed to 3.3 t / h (3.53 t / h as the flow rate when sent to the melting equipment 22), the linear velocity when the slurry was withdrawn from the slurry withdrawal port 20 of the hydraulic washing column 1 was changed to 1.3 m / s, and the liquid temperature at the outlet of the heat exchanger was changed to 20° C.

[0140] As a result, the crystal bed formed in the hydraulic washing column 1 could be broken down almost uniformly, and a product could be obtained.

[0141] Example 6 The same operations as in Example 2 were performed, except that the spray velocity from the circulating liquid supply unit was changed to 3.5 m / s, the spray liquid rate per opening (each round hole) of the circulating liquid supply unit was changed to 42 kg / h / unit, the spray liquid rate from the entire circulating liquid supply unit was changed to 5.8 t / h (6.03 t / h as the flow rate when sent to the melting equipment 22), the linear velocity when the slurry was withdrawn from the slurry withdrawal port 20 of the hydraulic washing column 1 was changed to 2.3 m / s, and the liquid temperature at the outlet of the heat exchanger was changed to 14°C.

[0142] As a result, the crystal bed formed in the hydraulic washing column 1 could be broken down almost uniformly, and a product could be obtained.

[0143] The above results are summarized in Table 1 below. The evaluation criteria in Table 1 below are as follows: ○: The crystal bed was able to be broken down approximately evenly, and a high-quality product was obtained. △: By adjusting the jetting speed, the crystal bed was able to be broken down approximately evenly, and a high-quality product was obtained. □: By adjusting the slurry supply amount and / or slurry concentration, the crystal bed was able to be broken down approximately evenly, and a high-quality product was obtained. ×: The crystal bed was able to be broken down, but not approximately evenly, and a product of the required quality could not be obtained. XXX: The crystal bed formed in the hydraulic washing column could not be broken down, and the purification apparatus could not be operated. In addition, the liquid was not supplied approximately evenly around the circulating liquid supply unit. It can be said that the effects of the present invention are achieved when the evaluations are ○, △, and □.

[0144] In Table 1 below, the spreading angle was determined by measuring the spreading angle when water was sprayed at the same speed in water from a liquid spray nozzle that had approximately the same thickness around the nozzle and the same shape and size as the opening of the circulating liquid supply unit.

[0145]

[0146] The results above indicate that a hydraulic washing column equipped with at least one circulating fluid supply unit having a circulating fluid outlet for spraying a circulating fluid containing a crystal grain melt into the hydraulic washing column, the circulating fluid supply unit having a circulating fluid outlet section formed by M or more circulating fluid outlets calculated based on predetermined requirements, and a circulating fluid supply region for supplying circulating fluid from outside the hydraulic washing column to the circulating fluid outlet section, the circulating fluid being sprayed from the circulating fluid outlet section in multiple, substantially horizontal directions into the hydraulic washing column through each circulating fluid outlet at a circulating fluid outlet velocity of 0.3 m / s or more, and the amount of circulating fluid sprayed from each circulating fluid outlet being 1.5 kg / h or more, can break down the crystal bed substantially uniformly and produce a high-quality product. While a spray rate of less than 1.5 kg / h can sometimes make the crystal bed difficult to break down, specifying the number of outlets and the spray rate as described above enables substantially uniform handling of the crystals.

[0147] 1: Hydraulic washing column 2: Filter 3: Mother liquor withdrawal pipe 4: Slurry supply pipe 11: Slurry supply line 11a: Slurry containing crystals 11b: Mother liquor 20: Slurry withdrawal port 21: Slurry circulation line 22: Melting equipment 23: Product withdrawal line 23a: Product 24: Return line 25: Return port P: Liquid transfer pump 101: Circulating liquid supply unit 120: Opening (circulating liquid jet port)

Claims

1. A method for producing a slurry containing crystal grains by supplying a liquid containing a melt of crystal grains into a container and discharging a slurry containing crystal grains from the container, comprising: the container includes at least one liquid supply unit having a liquid jet outlet therein for jetting a liquid containing the melt into the container; The liquid supply unit has a liquid jetting portion formed by M or more liquid jetting ports calculated according to the following requirements, and a liquid supply region that supplies liquid from outside the container to the liquid jetting portion, The method comprises spraying liquid from the liquid jetting portion in a plurality of different substantially horizontal directions, and supplying the liquid to the container through each liquid jetting port at a liquid jetting speed of 2 m / s or more. Requirement: M is the value obtained by dividing 360 by one of the following values (decimals are rounded down) 1) The angle of spread (°) when water is sprayed in water from a single liquid nozzle equivalent to that described above at the same speed. 2) In flow analysis (numerical calculation), the spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid nozzle equivalent to the above.

2. 2. The method according to claim 1, wherein in at least one of the liquid supply units, when viewed from above and below, all horizontal jetting difference angles are approximately the same when the angle formed by the jetting direction of liquid ejected from a liquid jet outlet and the jetting direction of liquid ejected from a liquid jet outlet adjacent to the liquid jet outlet is defined as the horizontal jetting difference angle.

3. 3. The method according to claim 1, wherein the positions of the liquid jetting ports forming the liquid jetting portion are arranged on a circle having a center at the liquid jetting portion when viewed from above and below.

4. 3. The method according to claim 1, wherein in at least one of the liquid supply units, the liquid jets are located at two or more different heights when viewed from the horizontal direction.

5. The method according to claim 1 or 2, wherein the slurry is discharged from at least four directions of the vessel at a linear velocity of 1 m / s or more.

6. 1. A method for producing a compound using a hydraulic wash column, comprising: the hydraulic washing column includes at least one circulating liquid supply unit having a circulating liquid outlet therein for injecting a circulating liquid containing a melt of crystal grains into the hydraulic washing column; The circulating fluid supply unit includes a circulating fluid jetting portion formed by M or more circulating fluid jetting ports calculated according to the following requirements: a circulating liquid supply region for supplying the circulating liquid from outside the hydraulic cleaning column to the circulating liquid jetting portion; The circulating fluid is jetted from the circulating fluid jetting portion in a plurality of different substantially horizontal directions, a circulating liquid supply port into the hydraulic washing column at a jetting velocity of 2 m / s or more through each circulating liquid jetting port, and a jetting rate of the circulating liquid from each circulating liquid jetting port of 10 kg / h or more. Requirement: M is the value obtained by dividing 360 by one of the following values (decimals are rounded down) 1) The angle of spread (°) when water is sprayed in water from a single liquid nozzle equivalent to that described above at the same speed. 2) In flow analysis (numerical calculation), the spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid spray nozzle equivalent to the above.

7. The number of the circulating liquid supply units is 30 to 90 cm when viewed from the top and bottom of the hydraulic washing column. ２ The manufacturing method according to claim 6, wherein the winning score is one point.

8. 8. The method according to claim 6, wherein the temperature of the circulating fluid is equal to or higher than the melting point of the compound + 1°C.

9. The method according to claim 6 or 7, wherein the compound is an organic compound having a solid density higher than a liquid density.

10. The method according to claim 6 or 7, wherein the compound is (meth)acrylic acid.

11. A method for producing a slurry containing crystal grains by supplying a liquid containing a melt of crystal grains into a container and discharging a slurry containing crystal grains from the container, comprising: the container includes at least one liquid supply unit having a liquid jet outlet therein for jetting a liquid containing the melt into the container; The liquid supply unit has a liquid jetting portion formed by M or more liquid jetting ports calculated according to the following requirements, and a liquid supply region that supplies liquid from outside the container to the liquid jetting portion, The method comprises spraying liquid from the liquid jetting portion in a plurality of different substantially horizontal directions and supplying the liquid to the container through each liquid jetting port at a liquid jetting speed of 0.3 m / s or more. Requirement: M is the value obtained by dividing 360 by one of the following values (decimals are rounded down) 1) The angle of spread (°) when water is sprayed in water from a single liquid nozzle equivalent to that described above at the same speed. 2) In flow analysis (numerical calculation), the spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid nozzle equivalent to the above.

12. 1. A method for producing a compound using a hydraulic wash column, comprising: the hydraulic washing column includes at least one circulating liquid supply unit having a circulating liquid outlet therein for injecting a circulating liquid containing a melt of crystal grains into the hydraulic washing column; The circulating fluid supply unit includes a circulating fluid jetting portion formed by M or more circulating fluid jetting ports calculated according to the following requirements: a circulating liquid supply region for supplying the circulating liquid from outside the hydraulic cleaning column to the circulating liquid jetting portion; The circulating fluid is jetted from the circulating fluid jetting portion in a plurality of different substantially horizontal directions, a circulating liquid supplying step for supplying the circulating liquid into the hydraulic washing column through each of the circulating liquid outlets at a jetting velocity of 0.3 m / s or more, and a jetting rate of the circulating liquid from each of the circulating liquid outlets of 1.5 kg / h or more. Requirement: M is the value obtained by dividing 360 by one of the following values (decimals are rounded down) 1) The angle of spread (°) when water is sprayed in water from a single liquid nozzle equivalent to that described above at the same speed. 2) In flow analysis (numerical calculation), the spread angle (°) when a liquid with the same physical properties is sprayed at the same speed from a single liquid spray nozzle equivalent to the above.