3 fluid nozzle

Abstract

To provide a three fluid nozzle capable of suppressing the local deposition of a fixed material on the inner wall of a heating furnace and producing fine particles reduced in the irregularity of physical properties in a good yield.SOLUTION: A three fluid nozzle comprising: a three fluid nozzle body including a discharge port having a horizontally long quadrangular shape in plan view, the discharge port including a liquid discharge port for discharging a liquid and a gas discharge port adjacent to a long side of the liquid discharge port; and a rotation mechanism for rotating the three fluid nozzle body about a central axis of the three fluid nozzle body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a three-fluid nozzle. [Background technology]

[0002] Examples of devices for producing fine particles include spray pyrolysis devices and spray drying devices. In these devices, a raw material solution is sprayed into a heating furnace from the liquid outlet of a fluid nozzle, such as a two-fluid nozzle or a three-fluid nozzle, to form a mist, and the mist is then pyrolyzed or dried in the heating furnace, thereby continuously producing fine particles (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-98867 Summary of the Invention [Problem to be solved by the invention]

[0004] Three-fluid nozzles are advantageous for increasing the production of fine particles because the mist particle size is smaller than that of two-fluid nozzles and the spray volume can be easily adjusted. However, the following problem has been discovered when continuously producing fine particles using a three-fluid nozzle. Specifically, the planar shape of the liquid outlet of a three-fluid nozzle is typically rectangular, and two gas outlets are installed adjacent to the long side of the liquid outlet. As a result, the mist shape becomes a square pyramid with long and short sides, as shown in Figure 4(a-1). The mist on the short sides is closer to the inner wall of the furnace, so it easily adheres to the furnace wall. The mist that adheres to the inner wall of the furnace forms deposits. These deposits then accumulate locally, and as the deposits grow, as shown in Figure 4(a-2), the pressure inside the furnace varies, creating a pressure difference at the bottom of the furnace. This disrupts the mist flow and makes it more likely to come into contact with the deposits, further promoting their growth. As a result, when a three-fluid nozzle is used, not only is the yield of microparticles significantly reduced, but the uneven distribution of radiant heat from the furnace makes it difficult to obtain microparticles with uniform physical properties. In contrast, with a two-fluid nozzle, the planar shape of the liquid outlet is typically circular, and a single gas outlet is installed around the liquid outlet, resulting in a conical mist shape, as shown in Figure 4(b-1). This maintains a substantially uniform distance between the mist and the inner wall of the furnace. Even if the mist adheres to the inner wall of the furnace and solidified material accumulates, the solidified material does not accumulate locally unevenly, as shown in Figure 3(b-2), but accumulates uniformly overall. As a result, when a two-fluid nozzle is used, the yield of microparticles is not significantly reduced, and the uneven distribution of radiant heat from the furnace is less likely to occur, thereby suppressing fluctuations in the physical properties of the microparticles. Therefore, the inventors have discovered that the reduction in microparticle yield and the unevenness of physical properties due to the localized accumulation of solidified material on the inner wall of the furnace are issues unique to three-fluid nozzles. In this specification, the term "mist" refers to fine droplets suspended and dispersed in a gas, or in other words, a mist of liquid. An object of the present invention is to provide a three-fluid nozzle that can suppress localized deposition of solidified material on the inner wall of a heating furnace and produce fine particles with little variation in physical properties with high yield. [Means for solving the problem]

[0005] After conducting various studies to solve the above-mentioned problems, the inventors discovered that by providing a rotation mechanism to the three-fluid nozzle body and rotating the three-fluid nozzle body when ejecting liquid, it is possible to suppress the local accumulation of solidified material on the inner walls of the heating furnace, thereby enabling the production of fine particles with little variation in physical properties with a high yield.

[0006] That is, the present invention provides the following [1] to

[10] . [1] A three-fluid nozzle body including a discharge port having a horizontally elongated rectangular shape in plan view, the discharge port having a liquid discharge port for discharging a liquid and a gas discharge port adjacent to the long side of the liquid discharge port; a rotation mechanism that rotates the three-fluid nozzle body around its central axis; A three-fluid nozzle. [2] The three-fluid nozzle according to [1], wherein the rotation mechanism rotates the three-fluid nozzle body back and forth around its central axis. [3] The three-fluid nozzle according to [2], wherein the reciprocating rotation is composed of an outward rotation in which the three-fluid nozzle body is rotated around its central axis until it reaches a rotation angle of 180°, and a return rotation in which the three-fluid nozzle body is rotated in the opposite direction to the outward rotation until it reaches a rotation angle of 180° around its central axis. [4] A three-fluid nozzle for spraying the raw material solution; A heating furnace that dries or thermally decomposes the mist of raw material solution sprayed from a three-fluid nozzle Equipped with The three-fluid nozzle is the three-fluid nozzle described in any one of [1] to [3] above. Spray dryer or spray pyrolysis equipment. [5] A three-fluid nozzle body including a discharge port having a horizontally elongated rectangular shape in plan view, the discharge port having a liquid discharge port for discharging a liquid and a gas discharge port adjacent to the long side of the liquid discharge port; a rotation mechanism that rotates the three-fluid nozzle body around the central axis of the three-fluid nozzle body; A method for producing fine particles using a three-fluid nozzle comprising: A method for producing microparticles, comprising the steps of spraying a mist of a raw material solution from the liquid outlet of a three-fluid nozzle while rotating the three-fluid nozzle body around its central axis, and then thermally decomposing or drying the mist. [6] The method for producing microparticles according to [5] above, wherein the mist of the raw material solution is sprayed from the liquid outlet of the three-fluid nozzle while the three-fluid nozzle body is rotated back and forth around its central axis. [7] The method for producing microparticles according to [6], wherein the reciprocating rotation is composed of an outward rotation in which the three-fluid nozzle body is rotated around its central axis until it reaches a rotation angle of 180°, and a return rotation in which the three-fluid nozzle body is rotated around its central axis in the opposite direction to the outward rotation until it reaches a rotation angle of 180°. [8] The method for producing fine particles according to any one of [5] to [7] above, wherein the raw material solution is an aqueous solution containing a compound containing one or more elements selected from Group 1 elements of the periodic table, Group 2 elements of the periodic table, Group 4 elements of the periodic table, Group 8 elements of the periodic table, Group 9 elements of the periodic table, Group 10 elements of the periodic table, Group 11 elements of the periodic table, Group 12 elements of the periodic table, Group 13 elements of the periodic table, Group 14 elements of the periodic table, and Group 15 elements, and containing one or more compounds selected from inorganic salts, organic salts, and alkoxides. [9] The method for producing fine particles according to any one of [5] to [8] above, wherein the raw material solution is an aqueous solution containing one or more compounds selected from sodium salts, potassium salts, magnesium salts, calcium salts, barium salts, titanium salts, zirconium salts, zinc salts, borates, boric acid, aluminum salts, aluminum alkoxides, and silicate alkoxides.

[10] The method for producing fine particles according to any one of [5] to [9] above, wherein the fine particles are inorganic oxide particles. [Effects of the Invention]

[0007] By using the three-fluid nozzle of the present invention, localized deposition of solidified material on the inner wall of the heating furnace is suppressed, and fine particles with little variation in physical properties can be produced with good yield. [Brief explanation of the drawings]

[0008] [Figure 1]1 is a schematic diagram showing an example of a three-fluid nozzle of the present invention. [Figure 2] 1A and 1B are plan views showing examples of the shape of a liquid ejection port of a fluid nozzle according to the present invention. [Figure 3] FIG. 1 is a schematic diagram showing an example of a spray pyrolysis apparatus or a spray drying apparatus equipped with a three-fluid nozzle of the present invention. [Figure 4] 1 is a schematic diagram showing an example of the shape of mist sprayed from a three-fluid nozzle or a two-fluid nozzle and the state of deposits on the inner wall of a heating furnace. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate explanations will be omitted. For convenience of illustration, the dimensional proportions of the drawings do not necessarily correspond to those in the description.

[0010] An example of a three-fluid nozzle of the present invention is shown in Figure 1. Figure 1(a) is a plan view, and (b) is a side view. A preferred embodiment will be described below with reference to Figure 1. As shown in FIG. 1( a), the three-fluid nozzle 10 has a three-fluid nozzle body 1 with a cylindrical outer periphery. A center edge 3 is provided on the top surface of the three-fluid nozzle body 1, and a discharge port 2 is provided approximately in the center of the center edge 3. The discharge port 2 includes a liquid discharge port 2a for discharging a liquid and a gas discharge port 2b for discharging a gas. The liquid discharge port 2a is provided approximately in the center of the discharge port 2 and discharges a liquid supplied from a liquid supply unit via a liquid line (not shown) within the center edge 3. Two gas discharge ports 2b are provided adjacent to the long side (longitudinal direction) of the liquid discharge port 2a and discharge a gas supplied from a gas supply unit via a gas line (not shown) within the center edge 3 toward the liquid discharged from the liquid discharge port 2a. As a result, the gas discharged from the gas discharge port 2b collides with and disperses the liquid discharged from the liquid discharge port 2a, forming a mist. Side blocks 4 are provided at both ends of the center edge 3.

[0011] The planar shape of the liquid ejection port 2a is a horizontally elongated rectangle. In this specification, the term "planar shape" refers to the shape of the three-fluid nozzle body 1 when viewed from directly above, and the term "horizontally elongated rectangle" refers to a rectangle whose width is longer than its length. This shape makes it easy to increase the amount of liquid sprayed without changing the particle size of the mist. The size of the liquid ejection port 2a can be appropriately set in accordance with the size of the three-fluid nozzle body 1, taking into account the amount of liquid sprayed, nozzle strength, etc.

[0012] The horizontally elongated rectangle is not particularly limited as long as it is a plane figure bounded by four points and four line segments connecting them, and has sides that are longer horizontally than vertically. For example, as shown in FIG. 2, examples include (a) a rectangle, (b) a parallelogram, (c) a rectangle with four sides of different lengths, and (d) a trapezoid. Among these, a rectangle and a parallelogram are preferred, and a rectangle is more preferred. The corners of the horizontally elongated rectangle may be angular or rounded.

[0013] 2, the size of the oblong rectangle constituting the liquid ejection port 2a is such that, when the length of the long side of the two sides sandwiching one angle α of the oblong rectangle is A and the length of the short side of the two sides sandwiching the diagonal angle γ is B, the ratio of the two (A:B) is preferably 30:1 to 1.5:1, more preferably 25:1 to 1.5:1, even more preferably 20:1 to 1.5:1, and even more preferably 10:1 to 1.5:1. By setting such a ratio, the liquid ejected from the liquid ejection port 1a and the gas ejected from the gas ejection port 1b can be sufficiently contacted, thereby making the particle size of the mist approximately uniform.

[0014] Examples of the gas supplied to the gas outlet 2b include air and inert gases such as nitrogen and argon, etc. Among these, air is preferred from the viewpoint of economy.

[0015] A rotation mechanism that rotates the three-fluid nozzle body 1 about its central axis is provided below the three-fluid nozzle body 1. The rotation of the three-fluid nozzle body 1 may be performed mechanically by attaching a motor or the like, or may be performed manually, and is not particularly limited. The rotation mechanism is not particularly limited as long as it can rotate the three-fluid nozzle body 1 around its central axis, and examples thereof include a bearing and a rotating belt.

[0016] The rotation mechanism shown in FIG. 1 is a bearing 5. As shown in FIG. 1, the bearing 5 is composed of three layers: an inner ring 5a, balls 5b, and an outer ring 5c. That is, the bearing 5 is an annular member having the inner ring 5a and the outer ring 5c ​​fitted around the inner ring 5a. A plurality of balls 5b are incorporated into the annular space formed between the inner ring 5a and the outer ring 5c ​​so that they can roll freely, and the outer ring 5c ​​is rotatable relative to the inner ring 5a. The inner wall of the inner ring 5a is fixed to the three-fluid nozzle body 1. The outer ring 5c ​​can be fixed to, for example, a heating furnace. The fixing means is not particularly limited as long as the three-fluid nozzle body 1 does not fall off, and examples of the fixing means include welding and bolts. When fixing the rotation mechanism to the three-fluid nozzle body 1, a pin-type, L-type, flat-type, metal fitting, or other metal fitting may be used.

[0017] The central axis of inner ring 5a fixed to three-fluid nozzle body 1 is the center of rotation of bearing 5 and coincides with the central axis of three-fluid nozzle body 1. As a result, when inner ring 5a rotates, three-fluid nozzle body 1 can be rotated around its central axis.

[0018] The rotation mechanism may rotate the three-fluid nozzle body 1 360° around its central axis, or may rotate it back and forth within a predetermined angular range. The rotation mechanism may perform multiple 360° rotations or back and forth rotations as one process. This prevents the mist from being sprayed in a concentrated manner on the short side. Even if the mist adheres to the inner wall of the heating furnace, the deposits are deposited approximately evenly on the inner wall of the heating furnace, thereby preventing localized deposition of the deposits. As a result, uneven radiant heat from the heating furnace is prevented, and fine particles with uniform properties can be obtained with high yield.

[0019] When a liquid supply tube or an air tube is connected to the three-fluid nozzle, twisting of these may occur, so the rotation mechanism preferably rotates the three-fluid nozzle body 1 back and forth around its central axis, more preferably through a rotation angle of 180° around its central axis, and even more preferably performs a forward rotation in which the body rotates around its central axis until a rotation angle of 180° is reached, and a return rotation in which the body rotates around its central axis in the opposite direction to the forward rotation until a rotation angle of 180° is reached.

[0020] The rotation mechanism may rotate the three-fluid nozzle body 1 at a constant speed or by a predetermined angle per unit time. When rotating at a constant speed, the speed can be appropriately set depending on the size of the three-fluid nozzle body 1 and the spray amount. For example, a speed of 0.001 to 3 rpm is preferred, 0.01 to 2 rpm is more preferred, and 0.1 to 1 rpm is even more preferred. When rotating at a predetermined angle per unit time, for example, rotation at a rotation angle of 15 to 90° every 30 minutes to 3 hours is preferred until a rotation angle of 180° is reached, rotation at a rotation angle of 30 to 60° every hour is more preferred until a rotation angle of 180° is reached, and rotation at a rotation angle of 30 to 45° every hour is even more preferred. Note that if the return path is performed under the same conditions as the outward path, the trajectories of the outward and return paths can be aligned, further suppressing localized deposition of solidified materials on the inner wall of the heating furnace.

[0021] The size of the three-fluid nozzle body 1 is not particularly limited and can be appropriately selected taking into consideration the amount of liquid to be sprayed, nozzle strength, etc. For example, the length of the three-fluid nozzle body 1 is 400 to 1500 mm. Furthermore, when the nozzle is cylindrical, the outer diameter of the three-fluid nozzle body 1 is, for example, φ40 to 80 mm. The three-fluid nozzle body 1 may be an industrially available one, or may be manufactured taking into consideration the specifications of the device, etc. Furthermore, the size of the rotation mechanism can be set appropriately depending on the size of the three-fluid nozzle body 1. The rotation mechanism may be an industrially available one, or may be fabricated taking into consideration the specifications of the device, etc.

[0022] The three-fluid nozzle body 1 may be of an internal mixing type in which the liquid and air are mixed inside the nozzle, or an external mixing type in which the liquid and air are mixed outside the nozzle, but the external mixing type is preferred in that it makes it easier to enjoy the effects of the present invention.

[0023] The three-fluid nozzle of the present invention has been described in detail above based on the embodiments. However, the present invention is not limited to the above embodiments. Various modifications of the present invention are possible without departing from the spirit and scope of the present invention. For example, as shown in FIG. 1(c), the three-fluid nozzle 10 may include a heat insulating material 6 that covers the outer periphery of the three-fluid nozzle body 1 while maintaining a predetermined distance therebetween. Alternatively, a protective tube (not shown) may be provided between the three-fluid nozzle body 1 and the heat insulating material 6, and the outer periphery of the protective tube may be covered with the heat insulating material 6. Examples of heat insulating materials include ceramic fiber, glass fiber, and castable.

[0024] The three-fluid nozzle of the present invention is useful as a fluid nozzle to be attached to a spray drying apparatus or a spray pyrolysis apparatus described below.

[0025] [Spray dryer or spray pyrolysis device] The spray pyrolysis apparatus or spray drying apparatus of the present invention is equipped with the three-fluid nozzle of the present invention. A preferred embodiment will now be described with reference to FIG.

[0026] FIG. 3 is a schematic diagram showing an example of the spray pyrolysis apparatus or spray drying apparatus of the present invention. 3, the spray pyrolysis apparatus or spray drying apparatus 100 includes a three-fluid nozzle 10 for spraying a raw material solution and a heater 12 for heating and drying or pyrolyzing a mist formed from the raw material solution in a heating furnace 11, and the three-fluid nozzle 10 is the three-fluid nozzle of the present invention. Specific embodiments of the three-fluid nozzle 10 are as described above.

[0027] One or more three-fluid nozzles 10 can be installed in the heating furnace 11, but the device shown in FIG.

[0028] The material of the heating furnace 11 is not particularly limited as long as it is one that is used as a furnace material, but examples include heat-resistant metals such as iron, stainless steel, Inconel, Hastelloy, and titanium, ceramics, bricks, and monolithic refractories. The shape of the heating furnace 11 can be selected appropriately, but may be, for example, a substantially cylindrical shape. The size of the heating furnace 11 can be selected appropriately depending on the production scale, but for example, if it is a vertical cylindrical furnace, the inner diameter is preferably 600 to 1600 mm, and the height is preferably 3000 to 10000 mm.

[0029] The heating device 12 is not particularly limited as long as it can provide the amount of heat required to dry or pyrolyze the raw material solution mist, and examples thereof include a combustion burner, a hot air heater, an electric heater, etc. One or more heating devices 12 can be installed, and the device shown in Figure 3 has eight installed. Note that any combustion burner, hot air heater, or electric heater that is commercially available can be used.

[0030] The spray drying apparatus or spray pyrolysis apparatus of the present invention has been described in detail above based on the embodiments. However, the present invention is not limited to the above embodiments. Various modifications of the present invention are possible without departing from the spirit of the present invention. For example, in the spray drying apparatus or spray pyrolysis apparatus 100, the fluid nozzle 10 and the heating furnace 11 are arranged vertically, but they are not limited to the vertical arrangement and may be horizontal or oblique.

[0031] [Method for producing fine particles] The method for producing fine particles of the present invention can be carried out by using the spray drying apparatus or spray pyrolysis apparatus of the present invention, and known methods such as spray pyrolysis, spray drying, etc. Hereinafter, as a preferred embodiment, a method for producing inorganic oxide particles using the spray drying apparatus or spray pyrolysis apparatus of the present invention will be described.

[0032] First, a raw material solution is prepared. The raw material solution is prepared, for example, by mixing a raw material compound with a solvent. The solvent is not particularly limited as long as it can dissolve the raw material compound, and examples thereof include water and organic solvents. Among these, water is preferred from the viewpoints of environmental impact and production costs. The raw material compound and solvent may be mixed by adding both simultaneously or by adding one to the other, and the mixing method is not particularly limited.

[0033] The raw material compound is not particularly limited as long as it contains elements constituting an inorganic oxide and is soluble in water, and examples thereof include inorganic salts, organic salts, alkoxides, etc. Examples of inorganic salts include nitrates, sulfates, carbonates, hydroxides, and halides. Examples of organic salts include formates, acetates, propionates, oxalates, and citrates. One or more raw material compounds can be used.

[0034] Examples of the raw material compound include compounds containing one or more elements selected from Group 1 elements of the periodic table, Group 2 elements of the periodic table, Group 4 elements of the periodic table, Group 8 elements of the periodic table, Group 9 elements of the periodic table, Group 10 elements of the periodic table, Group 11 elements of the periodic table, Group 12 elements of the periodic table, Group 13 elements of the periodic table, Group 14 elements of the periodic table, and Group 15 elements of the periodic table, and one or more compounds selected from inorganic salts, organic salts, and alkoxides.

[0035] Suitable raw material compounds include, for example, inorganic salts and alkoxides. Examples of inorganic salts include sodium salts, potassium salts, magnesium salts, calcium salts, barium salts, titanium salts, zirconium salts, zinc salts, borates, boric acid, and aluminum salts. Examples of alkoxides include aluminum alkoxides and silicate alkoxides.

[0036] Examples of sodium salts include sodium nitrate, sodium sulfate, sodium chloride, and sodium hydroxide. Examples of potassium salts include potassium nitrate, potassium sulfate, potassium chloride, and potassium hydroxide. Examples of magnesium salts include magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium phosphate, and magnesium hydroxide. Examples of calcium salts include calcium nitrate, calcium chloride, calcium hydroxide, calcium formate, calcium acetate, and calcium propionate. Examples of borates include metaborates such as sodium borate and potassium borate, tetraborates such as sodium tetraborate and potassium tetraborate, and pentaborates such as sodium pentaborate and potassium pentaborate. Examples of aluminum salts include aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum phosphate, aluminum hydroxide, aluminum acetate, and aluminum oxalate. Examples of silicate alkoxides include tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), tetrapropyl orthosilicate (TPOS), and tetrabutoxysilane. Furthermore, a solution in which aluminum oxide or silicon oxide is dispersed in a solvent, or a sol solution of aluminum oxide or silicon oxide can also be used as the raw material solution.

[0037] Among these, as the raw material compound, from the viewpoint of easily enjoying the effects of the present invention, one or more compounds selected from sodium salts, potassium salts, magnesium salts, calcium salts, barium salts, titanium salts, zirconium salts, zinc salts, borates, boric acid, aluminum salts, aluminum alkoxides, and silicate alkoxides are preferred, one or more compounds selected from sodium salts, potassium salts, magnesium salts, calcium salts, borates, boric acid, aluminum salts, aluminum alkoxides, and silicate alkoxides are more preferred, and it is even more preferred that the raw material compound contains at least an aluminum salt and a silicate alkoxide.

[0038] The total concentration of the raw material compounds in the raw material solution is usually from 0.01 mol / L to the saturated concentration, and preferably from 0.1 to 1.0 mol / L.

[0039] Next, while the three-fluid nozzle body is rotated by a rotation mechanism, the raw material solution is sprayed from the liquid outlet of the nozzle body, and at the same time, gas is ejected from the gas outlet toward the raw material solution, causing the liquid and gas to come into approximately uniform contact with each other to form a mist with approximately uniform particle size, and this mist is then dried or thermally decomposed.

[0040] The rotation mechanism may rotate the three-fluid nozzle body 1 through a rotation angle of 360° around its central axis, or may rotate it back and forth within a predetermined angular range, or may repeatedly perform 360° rotation or back and forth rotation. Among these, it is preferable to rotate the three-fluid nozzle body back and forth around its central axis, more preferably through a rotation angle of 180° around the central axis, and even more preferably to perform a forward rotation in which the three-fluid nozzle body is rotated around the central axis until it reaches a rotation angle of 180°, and a backward rotation in which the three-fluid nozzle body is rotated around the central axis in the opposite direction to the forward rotation until it reaches a rotation angle of 180°.

[0041] When rotating back and forth, the three-fluid nozzle body may be rotated at a constant speed or by a predetermined angle per unit time. In the former case, for example, the three-fluid nozzle body 1 may be rotated at a speed of preferably 0.001 to 3 rpm, more preferably 0.01 to 2 rpm, and even more preferably 0.1 to 1 rpm until a rotation angle of 180° is reached around the central axis of the three-fluid nozzle body 1. In the latter case, for example, the three-fluid nozzle body 1 is rotated at a rotation angle of 15 to 90° around the central axis of the three-fluid nozzle body 1 every 30 minutes to 3 hours until a rotation angle of 180° is reached, more preferably at a rotation angle of 30 to 60° every hour until a rotation angle of 180° is reached, and even more preferably at a rotation angle of 30 to 45° every hour until a rotation angle of 180° is reached. Note that the forward and backward rotations are preferably performed under the same conditions from the viewpoint of suppressing localized deposition of solidified materials on the inner wall of the heating furnace.

[0042] The liquid flow rate from the liquid outlet can be selected appropriately depending on the size of the three-fluid nozzle body, but from the viewpoint of increasing the production of fine particles and making the mist particle size approximately uniform, it is preferably 1 L / h or more, more preferably 5 L / h or more, even more preferably 10 L / h or more, and preferably 200 L / h or less, more preferably 150 L / h or less, and even more preferably 100 L / h or less. The pressure of the liquid supplied to the liquid outlet can be selected appropriately depending on the size of the three-fluid nozzle body and the liquid flow rate, but from the viewpoint of achieving approximately uniform mist particle size, it is preferably 0.05 MPa or more, more preferably 0.10 MPa or more, even more preferably 0.15 MPa or more, and preferably 0.60 MPa or less, more preferably 0.50 MPa or less, and even more preferably 0.40 MPa or less. The discharge speed of the raw material solution is preferably 1 m / s, more preferably 5 m / s or more, even more preferably 10 m / s or more, and is preferably 50 m / s or less, more preferably 35 m / s or less, even more preferably 20 m / s or less.

[0043] From the viewpoint of achieving approximately uniform mist particle size, the gas flow rate from the gas outlet is preferably 200 L / min or more, more preferably 250 L / min or more, even more preferably 500 L / min or more, and is preferably 1500 L / min or less, more preferably 1250 L / min or less, even more preferably 1000 L / min or less. The pressure of the gas supplied to the gas outlet can be selected appropriately depending on the size of the three-fluid nozzle body and the gas flow rate, but from the viewpoint of achieving approximately uniform mist particle size, it is preferably 0.1 MPa or more, more preferably 0.2 MPa or more, even more preferably 0.5 MPa or more, and preferably 1.0 MPa or less, more preferably 0.9 MPa or less, and even more preferably 0.85 MPa or less.

[0044] The temperature inside the heating furnace can be appropriately selected depending on the type of raw material solution, etc., but is preferably 200°C or higher, more preferably 400°C or higher, even more preferably 600°C or higher, and is preferably 1800°C or lower, more preferably 1500°C or lower, and even more preferably 1200°C or lower.

[0045] The inorganic oxide particles (fine particles) produced by drying or thermal decomposition are then transferred from downstream of the heating furnace to a recovery device by an induction fan and recovered. Examples of recovery devices include a cyclone powder recovery machine and a bag filter. Furthermore, when recovering the fine particles, the particle size may be adjusted by passing them through a filter. Furthermore, dust removal and purification equipment such as a scrubber may be installed downstream of the recovery device, if necessary.

[0046] Specific examples of inorganic compounds constituting the inorganic oxide particles include sodium oxide, potassium oxide, magnesium oxide, calcium oxide, barium oxide, zinc oxide, copper oxide, boron oxide, aluminum oxide, iron oxide, silicon oxide, aluminosilicate, aluminoborosilicate, borosilicate, and barium borosilicate.

[0047] The inorganic oxide particles produced by the method of the present invention can have the following properties: (i) The average particle size is preferably 5 μm or less, more preferably 4.5 μm or less, and even more preferably 4 μm or less. The lower limit of the average particle size is preferably 0.3 μm or more, more preferably 0.4 μm or more, and even more preferably 0.5 μm or more, from the viewpoint of ensuring sufficient voids. Here, in this specification, "average particle size" refers to the particle size (D50) corresponding to 50% of the cumulative distribution curve when the particle size distribution of a sample is plotted on a volume basis in accordance with JIS R 1629. For example, a laser diffraction / scattering particle size distribution analyzer can be used to measure the particle size distribution. (ii) particle density is preferably 0.70 g / cm 3 More preferably, it is 0.65 g / cm or less. 3 The lower limit of the particle density is usually 0.30 g / cm from the viewpoint of ensuring sufficient strength. 3 More than 0.40 g / cm is preferable. 3 More preferably, 0.50 g / cm 3The above is even more preferable. In this specification, "particle density" refers to a value measured by a gas displacement method in accordance with JIS R 1620. As a particle density measuring device, for example, a dry automatic density meter "AccuPic (manufactured by Shimadzu Corporation)" can be used.

[0048] The inorganic oxide particles produced by the method of the present invention have a small particle size and particle density, and are therefore useful for heat insulating materials, heat shielding materials, catalyst supports, building materials, electronic materials, and the like.

[0049] The microparticles produced by the spray drying apparatus or spray pyrolysis apparatus of the present invention may be solid particles, porous particles, hollow particles, or a mixture of two or more of these. Here, in this specification, "solid particles" refers to particles with a structure that does not have an internal cavity, and examples thereof include particles consisting of a single layer and particles having a core (also called an inner core) and a shell layer (also called an outer shell). Furthermore, "hollow particles" refer to particles with a structure that has an internal cavity (hollow portion) surrounded by an outer shell. The number of cavities may be single or multiple. Furthermore, "porous particles" refer to particles with a large number of through-holes that connect from the particle surface to the interior. The size and shape of the through-holes are not particularly limited. Furthermore, the particles may have closed pores inside. [Example]

[0050] The following examples will explain the present invention in more detail, but the present invention is not limited to the examples below.

[0051] 1. Measurement of the pressure difference at the bottom of the furnace Using a general differential pressure gauge (manometer), one end was connected to the bottom of the furnace and the other end was open to the atmosphere, and the difference with the atmospheric pressure was measured.

[0052] 2. Particle Density Measurement The density was measured by the gas displacement method using a dry automatic density meter (AccuPyc 1340, manufactured by Shimadzu Corporation). That is, after placing the sample in a cell, the cell was filled with an inert gas, and the volume of the sample was measured. The particle density was calculated from this volume and the sample mass measured in advance.

[0053] 3. Measurement of average particle size Using a particle size distribution analyzer (MT3000II, manufactured by Microtrackbell Co., Ltd.), a volume-based particle size distribution was created in accordance with JIS R 1629, and the particle diameter (D 50 ) was sought.

[0054] Preparation Example 1 Preparation of raw material solution A raw material solution was prepared by dissolving 0.04 mol of aluminum nitrate and 0.16 mol of tetraethyl orthosilicate in 300 liters of distilled water, and the solution was charged into the tank.

[0055] Example 1 The effectiveness of this method was demonstrated by producing inorganic oxide particles using the spray pyrolysis apparatus shown in Figure 2 according to the following procedure. The three-fluid nozzle used was the one shown in Figure 1(c), and a gas burner was used as the heat source for heating the raw material solution. Air was supplied to the three-fluid nozzle at 720 L / min along with the raw material solution, and a mist of the raw material solution was sprayed into the heating furnace at 42 L / h. The mist was passed through the heating furnace at an internal temperature of 1100°C to pyrolyze it and generate inorganic oxide particles, which were then collected using a collection device (bag filter). During this process, the three-fluid nozzle body was manually rotated 45° around its central axis every hour until it reached 180° in four hours, and then manually rotated 45° around the central axis of the three-fluid nozzle body in the opposite direction to the outward movement, returning to the initial position in four hours, for a total of 11 hours.

[0056] Example 2 Inorganic oxide particles were produced using the same procedures as in Example 1, except that the three-fluid nozzle body was manually rotated 90° around its central axis every two hours until it reached 180° in four hours, and then rotated 90° around the central axis of the fluid nozzle body in the opposite direction to the forward direction every two hours until it returned to the initial position in four hours, a total of 11 hours of back-and-forth rotation.

[0057] Comparative Example 1 Inorganic oxide particles were produced in the same manner as in Example 1, except that spraying was carried out for a total of 11 hours without rotating the three-fluid nozzle.

[0058] [Table 1]

[0059] In Comparative Example 1, the three-fluid nozzle body was not rotated when spraying the raw material solution, so that the deposits accumulated locally on the inner wall of the heating furnace, resulting in an uneven adhesion state of the deposits. As a result, not only was the yield (recovery rate) significantly reduced, but the large pressure difference at the bottom of the furnace caused a bias in the radiant heat from the heating furnace, resulting in inorganic oxide particles with large variations in particle density and average particle size. In contrast, in the Example, the three-fluid nozzle body was rotated when spraying the raw material solution, so the deposits did not become unevenly distributed on the inner wall of the heating furnace, but adhered uniformly throughout. As a result, the yield (recovery rate) was not significantly impaired, and the pressure difference at the bottom of the furnace was small, making it difficult for unevenness to occur in the radiant heat from the heating furnace, resulting in the production of inorganic oxide particles with reduced variations in particle density and average particle size. [Explanation of symbols]

[0060] 1 Three-fluid nozzle body 2 Liquid outlet 2a Liquid outlet 2b Gas outlet 3 Center Edge 4 Side Block 5 Bearings (rotating mechanism) 5a Inner circle 5b ball 5c outer ring 6. Insulation 10 Three-fluid nozzle 11 Heating furnace 12 Heating device 100 Spray pyrolysis equipment or spray drying equipment

Claims

1. a three-fluid nozzle body including a discharge port having a horizontally elongated rectangular shape in plan view, the discharge port having a liquid discharge port for discharging a liquid and a gas discharge port adjacent to the long side of the liquid discharge port; a rotation mechanism that rotates the three-fluid nozzle body around its central axis; A three-fluid nozzle comprising:

2. The three-fluid nozzle according to claim 1 , wherein the rotation mechanism rotates the three-fluid nozzle body back and forth around its central axis.

3. 2. The three-fluid nozzle according to claim 1, wherein the reciprocating rotation is composed of a forward rotation in which the three-fluid nozzle body is rotated around its central axis until it reaches a rotation angle of 180°, and a return rotation in which the three-fluid nozzle body is rotated in the opposite direction to the forward rotation in which it is rotated around its central axis until it reaches a rotation angle of 180°.

4. a three-fluid nozzle for spraying the raw material solution; A heating furnace that dries or thermally decomposes the mist of raw material solution sprayed from a three-fluid nozzle Equipped with The three-fluid nozzle is the three-fluid nozzle according to any one of claims 1 to 3. Spray dryer or spray pyrolysis equipment.

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