JP4640414B2 - Spray drying equipment - Google Patents

Description

  The present invention relates to a spray drying apparatus for spraying and drying a slurry, and more particularly to a spray drying apparatus capable of effectively preventing impurities from being mixed with a small variation in the particle size of the granules obtained.

  The spray drying apparatus is an apparatus for spraying a slurry composed of raw material powder, a solvent, a binder, and the like by a spraying unit such as a nozzle or a rotating disk and drying it instantaneously with hot air. Such a spray drying apparatus is conventionally used for obtaining granules in pharmaceuticals, fine ceramics and the like.

  As the spray unit of the spray drying apparatus, a pressure nozzle, a rotating disk, or the like is mainly used. In the case where a rotating disk is used as the spraying part, finer granules can be obtained as compared with the case where a pressure nozzle is used. Therefore, a rotating disk is preferably used as the spraying part. .

  The rotating disk generally has a disk shape, and includes a lower plate supported by a rotating shaft, a dispersion pin for spraying droplets, and an upper plate formed on the dispersion pin. Further, a slurry discharge part for discharging slurry onto the rotary disk and a holding part for holding the slurry discharge part are formed above the rotary disk (for example, Patent Document 1).

  However, in the spray drying apparatus having a rotating disk as described in Patent Document 1, when spray drying is continuously performed, the upper plate of the rotating disk and the slurry discharge unit are affected by the splash of the slurry and the effect of hot hot air. Adhesion (scaling) of the raw material occurs in the gap between the holding portion and the holding portion. When the raw material adheres to the gap between the upper plate and the holding portion, and this deposit accumulates, the deposit that has become a certain size due to deposition falls off and mixes into the product. A product with a uniform particle size cannot be obtained.

  Furthermore, due to the accumulation of deposits, friction due to the deposits occurs between the upper plate of the rotating disk that rotates at a high speed and the holding unit, and the friction causes wear of the upper plate or the holding unit. There is also a problem that the product is mixed as an impurity in the product and adversely affects the product.

Japanese Patent Laid-Open No. 10-118536

  The present invention has been made in view of such a situation, and prevents the adhesion of raw materials to the gap between the upper plate of the rotating disk and the holding unit that holds the slurry discharge unit, and reduces the variation in the particle size of the obtained granules. In addition, the present invention relates to a spray drying apparatus that can effectively prevent contamination of impurities.

In order to achieve the above object, a spray drying apparatus according to the present invention comprises:
A spray drying apparatus having a slurry discharge unit for discharging slurry, a holding unit for holding the slurry discharge unit, and a rotating disk for spraying the slurry discharged from the discharge unit radially,
An upper plate is formed on the rotating disk,
An upper plate of the rotating disk has an inner diameter larger than an outer diameter of the holding portion;
The range of r1-r2 is 0.5 to 2.0 mm, where r1 is the inner diameter of the upper plate of the rotating disk and r2 is the outer diameter of the holding portion.

Alternatively, the spray drying apparatus according to the present invention is
A spray drying apparatus having a slurry discharge unit for discharging slurry, a holding unit for holding the slurry discharge unit, and a rotating disk for spraying the slurry discharged from the discharge unit radially,
An upper plate is formed on the rotating disk,
The upper plate of the rotating disk and the holding portion are arranged so as not to overlap each other when viewed from the rotating shaft direction of the rotating disk,
The range of r1-r2 is 0.5 to 2.0 mm, where r1 is the inner diameter of the upper plate of the rotating disk and r2 is the outer diameter of the holding portion.

  In the present invention, the inner diameter of the upper plate of the rotating disk is made larger than the outer diameter of the holding part, or the upper plate of the rotating disk and the holding part are viewed from the rotation axis direction of the rotating disk. Thus, by disposing them so as not to overlap each other, it is possible to effectively prevent the raw material from adhering to the gap between the upper plate of the rotating disk and the holding portion. According to the present invention, since it is possible to prevent the raw material from adhering to the gap between the upper plate and the holding part, the impurities caused by the variation in the particle size of the product that causes the fall off of the deposit and the wear due to the deposit. Can be effectively prevented.

In the present invention, preferably,
The upper plate of the rotating disk has an inner diameter larger than the outer diameter of the holding portion, and
The upper plate of the rotating disk and the holding portion are arranged so as not to overlap each other when viewed from the rotating shaft direction of the rotating disk.

  The inner diameter of the upper plate of the rotating disk is larger than the outer diameter of the holding part, and the upper plate of the rotating disk and the holding part do not overlap each other when viewed from the direction of the rotation axis of the rotating disk. By disposing in, the effect of preventing the adhesion of the raw material to the gap between the upper plate of the rotating disk and the holding portion can be further enhanced.

  In the present invention, preferably, at least a part of the upper plate of the rotating disk is formed with a scraping means for scraping off deposits attached to the holding portion. By forming a scraping means for scraping off the adhering matter adhering to the holding part on the upper plate of the rotating disk, it is possible to effectively prevent the adhering substance from accumulating on the holding part.

  In this invention, Preferably, the said scraping means is arrange | positioned so that it may not contact with the said holding | maintenance part. The scraping means is means for scraping off the adhering matter adhering to the holding part by rotation of a rotating disk. For this reason, if the scraping means is arranged so as to come into contact with the holding portion, the scraping means and the holding portion are worn by rotation, and there is a possibility that a worn object is mixed in the product. Therefore, it is preferable to arrange the scraping means so as not to contact the holding portion.

In the present invention, preferably, the scraping means is arranged so as not to overlap the holding portion when viewed from the direction of the rotation axis of the rotating disk.
Alternatively, preferably, the scraping means has a part overlapping with the holding part when viewed from the rotation axis direction of the rotary disk.

  In the present invention, preferably, the scraping means has a moving mechanism that moves in a radial direction in accordance with the number of rotations of the rotating disk.

  In the present invention, it is preferable that the moving mechanism is a mechanism that moves away from the holding portion when the rotation number of the rotating disk increases, and approaches the holding portion when the rotation number of the rotating disk decreases.

  In the present invention, it is preferable that the scraping means includes a plurality of scraping pins, and the scraping pins are arranged at equal intervals in the circumferential direction of the upper plate of the rotating disk. By arranging the scraping pins at equal intervals in the circumferential direction, the rotation of the rotating disk can be stabilized.

  In the present invention, preferably, at least a part of the bottom surface of the holding portion facing the upper plate is formed with a taper that widens the gap with the upper plate toward the outer periphery.

  In the present invention, it is preferable that a taper is formed on at least a part of the upper surface of the inner peripheral side end of the upper plate so that a gap with the holding portion becomes wider toward the inner periphery.

  By providing a taper in at least a part of the holding plate and / or the upper plate of the rotating disk, a sufficient interval between the upper plate of the rotating disk and the holding portion can be secured. It is possible to more effectively prevent the raw material from adhering to the gap between the upper plate and the holding portion.

  In the present invention, it is preferable that the holding portion is provided with a gas discharge mechanism for discharging gas. By providing a gas discharge mechanism in the holding unit and discharging gas, it becomes possible to prevent adhesion of the raw material to the holding unit and to remove deposits attached to the holding unit.

  The method for drying a powder according to the present invention is characterized in that the slurry containing the raw material powder is spray-dried and granulated using any one of the above-described spray-drying apparatuses. According to the drying method of the present invention, since the spray drying apparatus of the present invention is used, a powder having a good particle size distribution and containing very little impurities can be obtained.

  According to the present invention, since it is possible to effectively prevent the adhesion of the raw material to the gap between the upper plate of the rotating disk and the holding portion, the variation in the particle size of the product that causes the deposit to fall off, and the wear due to the deposit It is possible to effectively prevent the contamination of impurities caused by.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is an overall configuration diagram of a spray drying apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an essential part of a spraying part of a spray drying apparatus according to an embodiment of the present invention,
FIG. 3 is a cross-sectional view of the main part of the spray section along the line III-III shown in FIG.
FIG. 4 is a cross-sectional view of a principal part of a spraying part of a spray drying apparatus according to another embodiment of the present invention,
FIG. 5 is a cross-sectional view of the main part of the spray section along the line V-V shown in FIG.
6 to 9 are cross-sectional views of main parts of a spray unit of a spray drying apparatus according to still another embodiment of the present invention,
FIG. 10 is a cross-sectional view of an essential part of a spraying part of a conventional spray drying apparatus.

First Embodiment As shown in FIG. 1, a spray-drying system according to an embodiment of the present invention includes a spray-drying device 1 that is a drying means, and a slurry that supplies slurry to the spray-drying device 1 via a slurry pump 11. It has a supply means, a hot air supply means for supplying hot air for drying via the blower 12, and an exhaust means (a cyclone 14, a bag filter 15, and a blower 16 for a recovery machine).

  In the spray drying system of the present embodiment, a slurry composed of raw material powder, a solvent, a binder, and the like is supplied from the slurry supply unit to the spray drying device 1 via the slurry pump 11, and hot air supply unit via the blower 12. The raw material is dried in the spray-drying apparatus 1 by the hot air for drying sent from to obtain granular raw material grains.

  The spray drying apparatus 1 includes a cylindrical drying cylinder 10 and a spray unit 2 located at the upper center of the drying cylinder 10. Slurry is supplied to the spray unit 2 from the slurry supply unit via the slurry pump 11, and the supplied slurry is radially directed toward the inner wall of the drying cylinder 10 by the spray unit 2. Sprayed. Then, the slurry sprayed by the spraying unit 2 is dried by hot air for drying sent from the hot air supply means via the blower 12, becomes granules, and is taken out from the dry material discharge port 13.

  As shown in FIG. 2, the spray unit 2 includes a rotating disk 3, a slurry hose (part of slurry supply means) 5, a rotating shaft 4, and a slurry hose 5 that are rotatably arranged via a rotating shaft 4. And a distributor 6 for holding. Further, the distributor 6 is fixed from the outer peripheral side by a lower end portion 7 a of the casing 7. The distributor 6 and the lower end portion 7 a of the casing 7 constitute a “holding portion” of the present invention.

  The slurry hose 5 has a discharge part 5a for discharging the slurry supplied from the slurry supply means. The slurry supplied from the slurry supply means is dropped to the vicinity of the rotary shaft 4 on the rotary disk 3 through the discharge unit 5a. In the present embodiment, as shown in FIG. 3, two slurry hoses 5 are arranged at 180 ° symmetrical positions around the rotation shaft 4, but the number and arrangement positions of the slurry hoses 5 are not particularly limited. When two or more slurry hoses 5 are disposed, it is preferable that the slurry hoses 5 be disposed at equal intervals in the circumferential direction of the rotating disk 3 so that dripping of the slurry is constant. Moreover, the material which comprises the slurry hose 5 is not specifically limited, For example, nylon etc. can be used.

  The rotating disk 3 has a disk shape and has a lower plate 31 supported by the rotating shaft 4. A plurality of dispersion pins 32 are arranged on the outer peripheral side upper surface of the lower plate 31 in the circumferential direction of the rotating disk 3. is there. Further, an upper plate 33 is fixed on the dispersion pin 32. The rotating disk 3 is rotatable by a rotating shaft 4, preferably at a rotation speed of 3000 to 8000 rpm, and slurry discharged from the discharge unit 5a can be sprayed radially by centrifugal force due to rotation.

  The concrete spraying method of the slurry by the spraying part 2 in this embodiment is shown next. First, the slurry is dropped in the form of droplets from the discharge unit 5a onto the surface of the lower plate 31 of the rotating disk 3. Next, the slurry droplets move to the outer peripheral side on the lower plate 31 by the centrifugal force generated by the rotation of the rotating disk 3, and adhere to the lower peripheral surface of the dispersion pin 32. Then, the slurry droplets adhering to the dispersion pin 32 rise on the surface of the dispersion pin 32 by centrifugal force, and are sprayed away from the dispersion pin 32 in the vicinity of the upper end of the dispersion pin 32.

  In the present embodiment, the upper plate 33 formed above the dispersion pins 32 has a function of stabilizing the spraying of slurry droplets. By forming the upper plate 33, the particle size of granules obtained The distribution can be sharpened. In the present embodiment, since the particle size distribution can be sharpened by forming the upper plate 33, the yield rate based on the particle size distribution can be increased by about 10%.

  In the present embodiment, as shown in FIG. 2, the inner diameter (r1) of the upper plate 33 of the rotary disk 3 is made larger than the outer diameter (r2) of the lower end portion 7a of the casing 7, and as shown in FIG. The upper plate 33 and the lower end portion 7a of the casing 7 are arranged so as not to overlap each other when viewed from the direction of the rotation axis 4.

  By doing so, it is possible to prevent the raw material from adhering to the gap between the upper plate 33 of the rotating disk 3 and the distributor 6. By preventing the adhesion of the raw material, it is possible to effectively prevent the variation in the particle size of the product caused by the falling off of the adhered matter and the mixing of impurities caused by the abrasion caused by the adhered matter.

  The inner diameter (r1) of the upper plate 33 may be larger than the outer diameter (r2) of the lower end portion 7a so that the upper plate 33 and the lower end portion 7a do not overlap each other when viewed from the direction of the rotation axis 4. Although the size is not particularly limited, the inner diameter (r1) of the upper plate 33 is preferably about 0.5 to 2.0 mm, more preferably 0.5 to less than the outer diameter (r2) of the lower end portion 7a. Increase by about 1.0 mm. If the difference between the inner diameter (r1) of the upper plate 33 and the outer diameter (r2) of the lower end portion 7a is too small, there is a risk that the raw material will adhere between the upper plate 33 and the lower end portion 7a. On the other hand, if the difference is too large, the rotating disk 3 must be made larger than necessary, which is not realistic.

  As shown in FIG. 10, in the spray unit 20 of the conventional spray drying apparatus, the inner diameter (r1a) of the upper plate 330 formed on the rotary disk 30 is the outer diameter (r2) of the lower end part 7 a of the casing 7. It was smaller than. Therefore, in the spray unit 20 of the conventional spray drying apparatus, the upper plate 33 and the lower end portion 7a of the casing 7 overlap each other when viewed from the direction of the rotation shaft 4, and the gap between the distributor 6 and the upper plate 330 is also present. However, it was very narrow, about 1-2 mm.

  Therefore, in the spray unit 20 of the conventional spray drying apparatus, when spray drying is continuously performed, adhesion of raw materials (scaling) occurs in the gap between the upper plate 330 and the distributor 6 due to the splash of slurry and the influence of hot hot air. Was. The raw material adheres to the gap between the upper plate 330 and the distributor 6, and the adhering matter accumulates. The adhering matter having a certain size due to the accumulation falls off and is mixed into the product. There was a problem that the variation became large.

  Further, due to the accumulation of the deposits, friction due to the deposits is generated between the upper plate 330 of the rotating disk 30 rotating at a high speed and the distributor 6. Further, due to this friction, a part of the upper plate 330 or the distributor 6 is abraded, and there is a problem that a worn object is mixed as an impurity in the product and adversely affects the product.

  On the other hand, in the present embodiment, the inner diameter (r1) of the upper plate 33 of the rotating disk 3 is made larger than the outer diameter (r2) of the lower end portion 7a of the casing 7, and when viewed from the direction of the rotating shaft 4, Since it arrange | positions so that the upper plate 33 and the lower end part 7a of the casing 7 may not mutually overlap, the problem of the deposit | attachment in the spraying part 20 of the conventional spray drying apparatus can be solved.

  Then, the slurry droplets sprayed from the spray unit 2 are dried by hot air for drying (preferably 180 to 230 ° C.) sent from the hot air supply means via the blower 12 shown in FIG. Then, it is taken out from the dry material discharge port 13. According to this embodiment, it is possible to obtain a granule having a good particle size distribution and containing very little impurities.

  The hot air for drying sent from the hot air supply means is recovered by the cyclone 14, the bag filter 15 and the recovery machine blower 16 as exhaust means together with the solvent and dust vaporized by spray drying.

Second Embodiment The spray unit 2a of the present embodiment shown in FIG. 4 has the same configuration and operation as those of the spray unit 2 of the first embodiment except for the following, and redundant description thereof is omitted.
Unlike the first embodiment, in the spray section 2a of the present embodiment, a scraping pin 34a is provided on the upper plate 33a of the rotating disk 3a in order to scrape deposits adhering to the outer peripheral surface of the lower end 7a of the casing 7. Is formed.

  In the spray unit 2 according to the first embodiment shown in FIGS. 2 and 3, it is possible to prevent the raw material from adhering to the gap between the upper plate 33 a and the distributor 6. However, depending on the rotation conditions of the rotating disk 3a and the type of raw material used, the deposit 9 (illustrated by a broken line) extends from the outer periphery of the lower end 7a of the casing 7 to the upper surface of the upper plate 33a as shown in FIG. ) May be generated.

  On the other hand, in this embodiment, the scraping pin 34a is formed on the upper plate 33a, and the rotating disk 3 is rotated so that the deposit 9 is scraped off. The scraping pins 34a are arranged at equal intervals in the circumferential direction of the upper plate 33a of the rotating disk 3a, as shown in FIG. 5 which is a cross-sectional view taken along the line V-V in FIG. In the present embodiment, as shown in FIG. 5, four scraping pins 34a are arranged, but the number is not particularly limited. When two or more scraping pins 34a are arranged, it is preferable to arrange them at equal intervals in the circumferential direction of the rotating disk 3a in order to ensure a rotational balance.

  In the present embodiment, the upper plate 33a is provided with a spring 35a. The spring 35a holds the scraping pin 34a on the inner peripheral side of the rotating disk 3a by its elastic force. The scraping pin 34a uses the elastic force of the spring 35a, and can move in the radial direction according to the number of rotations of the rotating disk 3a. That is, the scraping pin 34a moves to the outer peripheral side due to the centrifugal force due to the rotation when the rotation number of the rotating disk 3a increases, and conversely, when the rotation number of the rotating disk 3a decreases, the elastic force of the spring 35 causes It has a structure that moves to the inner circumference side.

  The deposit 9 tends to be generated when the rotational speed of the rotating disk 3a is relatively small, and conversely, it hardly occurs when the rotational speed of the rotating disk 3a is relatively large. In addition, if the scraping pin 34 a is near the lower end 7 a of the casing 7 when the rotational speed is high, there is a possibility that the rotation of the rotary disk 3 will be obstructed. Therefore, the scraping pin 34a is preferably provided with a moving mechanism as described above.

  The scraping pin 34a is preferably arranged so as not to contact the distributor 6 and the lower end 7a of the casing 7, and the distance between the scraping pin 34a and the lower end 7a is about 2 mm at the shortest. It is preferable to do. If the scraping pin 34a and the lower end portion 7a of the casing 7 are arranged so as to come into contact with each other, the scraping pin 34a or the lower end portion 7a is worn by rotation, and the worn product is mixed into the product. There is a risk that.

  The material constituting the scraping pin 34a is not particularly limited, and examples thereof include stainless steel, alumina ceramics, and zirconia ceramics. Among these, from the viewpoint of preventing contamination due to wear, it is preferable to use a material harder than the raw material powder to be dried by a spray dryer, and particularly, alumina-based ceramics and zirconia-based ceramics are preferably used. it can.

Third Embodiment The spray unit 2b of the present embodiment shown in FIG. 6 has the same configuration and operation as those of the spray unit 2a of the second embodiment except for the following, and redundant description thereof will be omitted.
Unlike the second embodiment, the spray section 2b of the present embodiment scrapes deposits that adhere to the outer peripheral surface of the lower end 7a of the casing 7 and the lower surface of the distributor 6 on the upper plate 33b of the rotating disk 3b. An L-shaped scraping pin 34b for taking is formed.

  The L-shaped scraping pin 34b of the present embodiment is the same as that of the second embodiment, except that it can scrape not only the outer peripheral surface of the lower end portion 7a of the casing 7 but also the adhered matter attached to the lower surface of the distributor 6. The same effect is produced.

Fourth Embodiment The spray unit 2c of the present embodiment shown in FIG. 7 has the same configuration and operation as those of the spray unit 2 of the first embodiment except for the following, and redundant description thereof is omitted.
In the spray part 2c of this embodiment, unlike the first embodiment, a taper 6c-1 is formed on the lower surface of the distributor 6c so that the gap with the upper plate 33 becomes wider toward the outer periphery. In the present embodiment, by forming the taper 6c-1 on the lower surface of the distributor 6c, it is possible to secure a sufficient interval between the upper plate 33 and the distributor 6c. The adhesion of the raw material can be more effectively prevented.

  The taper 6c-1 formed on the lower surface of the distributor 6c may be formed on at least a part of the distributor 6c. For example, the taper starting point 6c-2 and the taper angle can be arbitrarily set according to the purpose. is there.

Fifth Embodiment The spray unit 2d of the present embodiment shown in FIG. 8 has the same configuration and action as the spray unit 2 of the first embodiment except for the following, and redundant description thereof will be omitted.
In the spray part 2d of the present embodiment, unlike the first embodiment, the upper surface of the upper plate 33d of the upper plate 33d of the rotating disk 3d is tapered so that the gap with the distributor 6 becomes wider toward the inner periphery. 33d-1 is formed. In the present embodiment, by forming the taper 33d-1 on the upper surface of the inner peripheral side end portion of the upper plate 33d, a sufficient interval between the upper plate 33d and the distributor 6 can be ensured. Adhesion of the raw material to the gap with 6 can be more effectively prevented.

  The taper 33d-1 formed on the upper surface of the inner peripheral side end portion of the upper plate 33d may be formed on at least a part of the upper surface of the inner peripheral side end portion of the upper plate 33d. For example, the taper start point 33d-2 The taper angle can be arbitrarily set according to the purpose.

Sixth Embodiment The spray unit 2e of the present embodiment shown in FIG. 9 has the same configuration and operation as those of the spray unit 2 of the first embodiment except for the following, and redundant description thereof is omitted.
In the spray unit 2e of this embodiment, unlike the first embodiment, the distributor 6e is provided with a gas discharge hose 8, and gas is discharged from the gas discharge unit 8a provided on the outer peripheral side surface of the casing 7e. It can be done.

  In the present embodiment, by discharging the gas from the gas discharge portion 8a through the gas discharge hose 8, it is possible to prevent the raw material from adhering to the outer peripheral surface of the casing 7e, and if the raw material has adhered. Even in the case, the deposits can be effectively removed. The gas discharge portions 8a are preferably formed on at least a part of the outer peripheral surface of the casing 7e, and a plurality of gas discharge portions 8a can be formed as necessary.

  In the present embodiment, the gas discharge portion 8a is formed on the outer peripheral surface of the casing 7e, but may be formed on the lower surface of the distributor 6e. In this case, the adhesion of the raw material on the lower surface of the distributor 6e is performed. Can be prevented. Moreover, you may form the gas discharge part 8a in both the outer peripheral surface of the casing 7e, and the lower surface of the distributor 6e.

The gas discharged from the gas discharge portion 8a is not particularly limited, and may be appropriately selected according to the raw material to be spray-dried. For example, air or N ₂ gas can be used, and moisture is contained as necessary. May be. Moreover, it is preferable that the temperature of the gas discharged from the gas discharge part 8a is about normal temperature-about 400 degreeC, More preferably, the same thing as the hot air for drying supplied from a hot air supply means via the air blower 12 is used.

Other Embodiments The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

  For example, in each of the above-described embodiments, the dispersion pins 34a and 34b, the tapers 6c-1 and 33d-1, and the gas discharge portion 8a are formed separately. However, as long as the operational effects of the present invention are not impaired, these are provided. It is also possible to form a composite.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

  First, a ceramic raw material was prepared as a starting raw material, the ceramic raw material, a binder, and pure water were stirred and mixed, and then mixed and pulverized using a compounding pulverizer to produce a ceramic slurry.

  Next, the obtained ceramic slurry was spray dried using the spray drying apparatus (Example) of the present invention having the spray section 2 shown in FIGS. The spray drying conditions were such that the rotational speed of the rotary disk 3 was 3500 rpm and the temperature of the hot air for drying was 190 ° C. Further, the difference between the inner diameter (r1) of the upper plate 33 of the spray part 2 and the outer diameter (r2) of the lower end part 7a of the casing 7 was 2.0 mm.

  Further, separately from the above, the obtained ceramic slurry was spray-dried using the conventional spray-drying apparatus (comparative example) having the spray section 20 shown in FIG.

  Visual inspection and measurement of non-defective product ratio of ceramic granules obtained using the spray drying apparatus (Example) of the present invention and ceramic granules obtained using a conventional spray drying apparatus (Comparative Example) Went.

  The appearance inspection was performed by evaluating whether or not black foreign substances exist and whether or not there is a lump of granules. The appearance inspection was performed for the number of inspection lots shown in Table 1. A lot where black foreign matter or a lump of granules existed was determined as a defective lot, and the ratio of the number of defective lots to the number of inspection lots was determined as a defective rate. It is preferable that the defect rate is low. The results are shown in Table 1.

  The measurement of the non-defective product ratio of the granule is performed by measuring the particle size distribution of the obtained ceramic granule. The particle having a particle size in the range of 300 μm or less is determined to be non-defective, and the weight of the non-defective product with respect to the total weight of the particle is obtained. The non-defective product rate. The results are shown in Table 2. It is preferable that the yield rate is high.

Evaluation 1
From Table 1, the ceramic granule obtained using the spray-drying apparatus (Example) of the present invention did not have any black foreign matter and no mass of granules, and gave good results. On the other hand, in the ceramic granule obtained using the conventional spray drying apparatus (comparative example), black foreign substances and agglomeration of the granule were confirmed, and the defect rate was 1.38%. In addition, the black foreign material confirmed in the comparative example is a worn object that is mixed when a part of the upper plate 330 of the distributor 6 and / or the rotating disk 30 is worn. And deposits deposited between the rotating disk 30 and the upper plate 330.

  From this result, it can be confirmed that by using the spray drying apparatus (Example) of the present invention, it is possible to effectively prevent the adhesion of the raw material to the gap between the upper plate of the rotating disk and the distributor (holding portion). It was.

Evaluation 2
From Table 2, the ceramic granule obtained using the spray drying apparatus (Example) of the present invention had a good product ratio of 94.0%, which was a good result. On the other hand, the ceramic granule obtained using the conventional spray drying apparatus (comparative example) had a non-defective product ratio of 87.6%, less than 90%, and a poor product ratio.

  From this result, it was confirmed that the dispersion of the particle size distribution can be eliminated by using the spray drying apparatus (Example) of the present invention, and as a result, the yield rate can be improved.

FIG. 1 is an overall configuration diagram of a spray drying apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the main part of the spray unit of the spray drying apparatus according to one embodiment of the present invention. FIG. 3 is a cross-sectional view of the main part of the spray section along the line III-III shown in FIG. FIG. 4 is a cross-sectional view of a main part of a spraying part of a spray drying apparatus according to another embodiment of the present invention. FIG. 5 is a cross-sectional view of the main part of the spray section along line VV shown in FIG. FIG. 6 is a cross-sectional view of an essential part of a spray portion of a spray drying apparatus according to still another embodiment of the present invention. FIG. 7 is a cross-sectional view of an essential part of a spray portion of a spray drying apparatus according to still another embodiment of the present invention. FIG. 8 is a cross-sectional view of an essential part of a spray portion of a spray drying apparatus according to still another embodiment of the present invention. FIG. 9 is a cross-sectional view of an essential part of a spray portion of a spray drying apparatus according to still another embodiment of the present invention. FIG. 10 is a cross-sectional view of an essential part of a spraying part of a conventional spray drying apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Spray drying apparatus 10 ... Drying cylinder 11 ... Slurry pump 12 ... Blower 13 ... Drying material discharge port 14 ... Cyclone 15 ... Bag filter 16 ... Blower 2 for recovery machines ... Spraying part 3 ... Rotary disk 31 ... Lower plate 32 ... Dispersion pin 33 ... Upper plate 4 ... Rotating shaft 5 ... Slurry hose 5a ... Discharge part 6 ... Distributor 7 ... Casing 7a ... Lower end part

Claims (13)

A spray drying apparatus having a slurry discharge unit for discharging slurry, a holding unit for holding the slurry discharge unit, and a rotating disk for spraying the slurry discharged from the discharge unit radially,
An upper plate is formed on the rotating disk,
An upper plate of the rotating disk has an inner diameter larger than an outer diameter of the holding portion;
The upper plate of the rotating disk and the holding portion are arranged so as not to overlap each other when viewed from the rotating shaft direction of the rotating disk,
The top plate of the inner diameter of the rotary disk r1, the outer diameter of the holding portion when the r2, range of r1-r2 is Ri 0.5~2.0mm der,
The spray-drying apparatus characterized by the gap of the said holding | maintenance part and the said upper board being 1-2 mm . The spray-drying apparatus according to claim 1 , wherein scraping means for scraping off deposits attached to the holding portion is formed on at least a part of the upper plate of the rotating disk. The spray drying apparatus according to claim 2 , wherein the scraping unit is disposed so as not to contact the holding unit. The spray drying apparatus according to claim 2 or 3 , wherein the scraping means is disposed so as not to overlap the holding portion when viewed from the direction of the rotation axis of the rotating disk. The spray-drying device according to claim 2 or 3 , wherein the scraping means has a part overlapping with the holding part when viewed from the rotation axis direction of the rotary disk. The spray drying apparatus according to any one of claims 2 to 5 , wherein the scraping means has a moving mechanism that moves in a radial direction in accordance with the number of rotations of the rotating disk. The spray drying apparatus according to claim 6 , wherein the moving mechanism is a mechanism that moves away from the holding unit when the rotation number of the rotating disk increases and approaches the holding unit when the rotation number of the rotating disk decreases. Said scraping means is constituted by a plurality of scraping pin, the scraping pin according to any one of claims 2 to 7 are arranged at equal intervals on the upper plate in the circumferential direction of the rotary disk Spray drying equipment. The spray according to any one of claims 1 to 8 , wherein a taper is formed on at least a part of a bottom surface of the holding portion facing the upper plate so that a gap with the upper plate becomes wider toward an outer periphery. Drying equipment. Wherein at least a portion of the inner peripheral end upper surface of the upper plate in rotation disk, any one of the preceding claims, tapered like a gap between the holding portion toward the inner periphery is wider is formed The spray-drying apparatus as described in 2. The spray drying apparatus according to any one of claims 1 to 10 , wherein the holding unit includes a gas discharge mechanism for discharging gas. The spray drying apparatus according to claim 11, wherein a gas discharge portion of the gas discharge mechanism is formed on an outer peripheral side surface of the holding portion.   The rotating disk includes a lower plate, an upper plate, and dispersion pins that connect the lower plate and the upper plate at a plurality of positions in the circumferential direction on the outer peripheral side of the lower plate. The spray-drying apparatus as described.

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