JPH072201B2 - Spray dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is suitable for high-mix low-volume production and is organically integrated with a housing or a building that can obtain a high-purity fine powder product. The present invention relates to a spray dryer.

[Prior Art] A spray dryer basically has three essential functions: spraying a stock solution, drying sprayed microdroplets, and separating and collecting fine powder products. In general, it is equipped with a sprayer, a drying chamber and a fine powder collector.

As an example of such a spray-drying device, those shown in FIGS. 4 and 5 are conventionally known. (Japanese Patent Sho 58-
32601 and Japanese Utility Model Laid-Open No. 58-26950) In the spray dryer of FIG. 4, the stock solution sprayed from the nozzle 5 is instantaneously heated in the drying chamber 1 by the hot air blown from the inlet 2. The liquid component is evaporated and the solid component is made into fine powder. Most of the fine powder is taken out as a product through the rotary valve 6, but a part of the fine powder is entrained by the hot air, passes through the exhaust port 3, and is recovered from the rotary valve 8 in the cyclone 7.

The spray dryer shown in FIG. 5 is of a type in which a rotary spray disk 10 is used as a sprayer instead of the nozzle 5.

In the spray drying apparatus of the type shown in FIGS. 4 and 5, the fine product powder is collected separately from the apparatus main body and the cyclone as described above, but in this case, it is relatively lightweight and has a small particle size. A cyclone is used, and a relatively large weight and large particle size is taken out from the main body of the apparatus, resulting in minute composition separation of the product.

In the past, this composition separation did not pose a problem depending on the type of product.

By the way, recently, as for the spray drying method and apparatus, a multi-product small-quantity production system for pharmaceuticals, fine ceramics and the like has been demanded from a conventional small-product mass production system.

In addition, the number of cases in which higher-purity products are required as products has increased.

[Problems to be solved by the invention]

As described above, the demand for a high-mix low-volume production method and the production of high-purity products has brought about new problems in addition to the above-mentioned composition separation, which has hardly been a problem in the conventional case.

In other words, due to frequent switching of product types, it has become necessary to quickly and completely wash the adhered solids on the inner wall of the drying chamber. Because
It takes a fatal defect to take a long time for cleaning in order to efficiently perform high-mix low-volume production, and when high purity and high quality are required for product quality, the adhered solid content is completely removed when changing product types. Cleaning is necessary, but in reality, complete cleaning is extremely difficult. In addition, if the product is harmful to the human body, it cannot be directly touched and cleaning is extremely difficult.

In addition, the minute composition separation as described above has also become a problem due to the demand for high-purity products.

(Means for Solving the Problems) The inventors of the present invention have conducted intensive studies in view of the above-mentioned problems of the conventional technology, and as a result, the spray drying chamber is formed of a porous film, and the spray drying device is installed in the housing or the building. The inventors have found that the above problems can be solved by organically arranging the respective element devices of (1) above, and arrived at the present invention.

That is, according to the present invention, a housing having two upper and lower chambers, in which at least a hot air generator, a hot air distributor, a stock solution atomizer, and an exhaust device are provided individually or in a plurality, and a lower chamber is provided. The powder product recovery device is movably arranged, and the bag-shaped or cylindrical heat resistance and good peelability are provided between the stock solution atomizer in the upper chamber and the corresponding powder product recovery device. There is provided a spray drying apparatus characterized in that a spray drying chamber composed of a porous film is detachably provided.

Since the spray-drying apparatus of the present invention handles a wide variety of products, the replacement of the porous film used for each product can be carried out easily and quickly. Further, in the present invention, by movably disposing the minimum device in the lower chamber of the housing, a large space can be secured except when in use, and thus a large number of porous membranes can be stored, and the product Used for temporary storage and cleaning of parts,
It will be extremely convenient.

The porous film used in the present invention is disposed between the stock solution atomizing device in the upper chamber and the powder product collecting device corresponding thereto, and constitutes the spray drying chamber. It must be excellent.

That is, the temperature of the hot air introduced into the spray drying chamber is usually about 120 to 280 ° C at the inlet temperature and about 150 to 70 ° C at the outlet temperature. However, since it is deposited, it must have good peelability for continuous use. Further, this porous membrane separates the target product fine powder from gas.

The type of the porous membrane having such a function is not particularly limited, but a cloth made of fiber or a combination membrane in which two or more kinds thereof are combined is usually used. As a preferable porous membrane, one having a good releasability network membrane laminated with a woven or non-woven fabric as a strength material is used. In this case, specifically, the mesh membrane is polytetrafluoroethylene (PTFE). (Teflon) -based film, polytrifluoroethylene-based film, woven fabric, and non-woven fabric are preferably made of polyimide, heat-resistant nylon, polyester, or aramid.

[Action]

The undiluted solution sprayed in the bag-shaped or cylindrical drying chamber made of a porous film disposed in the housing is instantaneously heated and dried by the hot air with an inlet gas temperature of 120 to 280 ° C blown from the inlet, And becomes fine powder. Most of the fine powder sinks to the bottom of the drying chamber due to its own weight, while the gas is separated from the remaining fine powder through the ventilation holes of the porous membrane and exhausted to the outside through the exhaust device. Therefore, since all the fine powder is separated from the gas by the porous film, the composition separation of the product fine powder does not occur.

In continuous operation, fine powder adheres to and deposits on the porous film, pressure loss increases, and the operation must be stopped at last, so the fine powder must be appropriately blown off. At that time, since the drying chamber is formed of a bag-like or tubular porous film with good peelability, the adhered powder is mechanically vibrated, or air is jetted (pulse air) from the opposite side in a short time. It can be easily brushed off. In addition, when changing the product type, the porous membrane that constitutes the drying chamber is dedicated to each product type in advance, and since the porous film is detachably attached, it is not necessary to replace the porous film. It is quick and easy.

〔Example〕

Next, the present invention will be described in more detail based on the embodiments shown in the accompanying drawings.

1 and 2 show an embodiment of a spray drying device according to the present invention. FIG. 1 is a perspective view of the entire device, and FIG. 2 (a) is an upper chamber of a housing in the spray drying device. FIG. 2B is a plan view of the lower chamber of the housing in the spray dryer. In the figure, the housing 11 is the upper chamber
The upper chamber 12 is provided with three sets of hot air generators 14, hot air distributors 15, and stock solution atomizers 16, respectively. In addition, the exhaust device 17 is integrated. On the other hand, the lower chamber 13 has the stock solution atomizer 16 of the upper chamber 12.
Corresponding to the number of the above, that is, three sets of powder product collecting devices 18 are provided below the stock solution atomizing device 16. Incidentally, the lower chamber 13, further provided with a powder dust removal device 19 _a, 19 _b and stock adjustment device 20, also stock atomization of the upper chamber 12 16
A large number of bag-like porous membranes 22 for the spray-drying chamber 21 formed between each of them and the corresponding powder product recovery device 18 are provided.

Therefore, the operation of this spray dryer will be described with reference to FIG. The apparatus shown in FIG. 3 has a configuration in which two sets of spray-drying chambers are housed, and products of different types are respectively provided.
A ₁ and B ₁ are manufactured. Among them, one set will be described. The stock solution A supplied from the stock solution adjusting device 20 through the pipe 23 and sprayed by the stock solution atomizing device 16 into the spray drying chamber 21 has a hot air generator 14 and a hot air distributor 15. It is instantaneously heated and dried by the hot air X blown through to become gas and fine powder. The fine powder is collected by the powder product collecting device 18 as the product A ₁ . Next, in the case of manufacturing a different type of product A ₂ or A ₃ similar to the product A ₁ , the porous film 22 forming the spray drying chamber 21 is removed, and the product A ₂ installed near it is removed. Alternatively, it can be quickly replaced with a porous membrane dedicated to A ₃ . The same operation is performed for the other pair.

On the other hand, the gas is separated from the fine powder through the ventilation holes of the porous film and is discharged to the outside from the common exhaust device 17.

Hereinafter, the spray dryer of the present invention will be described more specifically.

(Example 1) using the spray-drying apparatus of the type shown in Figure 3, lanthanum-added barium titanate as a dry object [BaTiO ₃ +0.01,0.0
150.02 (La ₂ O ₃ )] with a stock solution concentration of 70% and a throughput of 10
It was sprayed at a rate of 0 kg / Hr. The dryer used is A type, and the drying chamber has a diameter of 2000 mm, a straight body height of 500 mm and a total height of 3500 mm.
The upper part of the above was cylindrical and the lower part was in the shape of a funnel, and as the porous film constituting the drying chamber, a combination film obtained by laminating polytetrafluoroethylene on heat-resistant nylon non-woven fabric was used exclusively for each of three bags. The hot air inlet temperature is about 22
The exhaust air temperature was 120 ° C.

The stock solution was spray-dried under the above conditions. as a result,
The properties of the product fine powder were as follows.

In addition, (1) shows the case where 0.01% lanthanum is added, (2) shows the case where 0.015% lanthanum is added, and (3) shows the case where 0.02% lanthanum is added.

And, it took about 30 minutes to switch products, and it took only 30 minutes.

Further, in this example, at the time of switching, cleaning was performed only with the atomizing device, the drying chamber was folded, hung on a dedicated hook for storage, and reused for the next drying.

〔The invention's effect〕

As described above, in the spray drying apparatus of the present invention, the spray drying chamber is made of a porous film, and each element device of the spray drying apparatus is organically integrated in the housing. Can store a large space when not in use,
Can be used for other work or storage. In addition, several hot air generators of substantially the same size, hot air distributors, and juxtaposed element devices in a spray dryer such as a stock solution atomizer, and by preparing a large number of porous membranes for each product type, There is a great advantage that the same effect and action as the installation of several tens of dedicated spray dryers can be achieved with a small equipment area and equipment cost.

[Brief description of drawings]

FIG. 1 is a perspective view of the entire apparatus showing an embodiment of the present invention, FIG. 2 shows a spray drying apparatus which is an embodiment of the present invention, (a) is a plan view of the upper chamber of the housing, (B) is a plan view of the lower chamber of the housing. FIG. 3 is an explanatory diagram for explaining the operation of the present invention. 4 to 5 are schematic cross-sectional views showing a conventional spray dryer. 11 ... Housing, 12 ... Upper chamber, 13 ... Lower chamber, 14 ... Hot air generating device, 15 ... Hot air distribution device, 16 ... Stock solution atomizing device, 17 ... Exhaust device, 18 ... Powder product recovery device, _19a , 19 _b ... powder removal device, 20 ... stock solution adjusting device, 21 ... spray drying chamber, 22 ... porous membrane.

Front page continuation (72) Inventor Hiroki Takahashi 1-13-1, Nihonbashi, Chuo-ku, Tokyo, TDC Inc. (72) Inventor Masaaki Okawara 3847 Ikebe-cho, Midori-ku, Yokohama-shi, Kanagawa Okawara Kakoki Co., Ltd. (72) Inventor Katsumi Kobayashi 3847 Ikebe-cho, Midori-ku, Yokohama-shi, Kanagawa Okawara Kako Koki Co., Ltd. (72) Inventor Takashi Ito 3847, Ikebe-cho, Midori-ku, Yokohama-shi, Kanagawa Okawara Kakoki (56) Reference Documents JP 62-152501 (JP, A) JP 57-43212 (JP, B2) JP 52-28862 (JP, Y2)

Claims (1)

[Claims] 1. A housing comprising two upper and lower chambers, wherein at least a hot air generator, a hot air distributor, a stock solution atomizer, and an exhaust device are provided in the upper chamber, respectively. The product recovery device is movably arranged, and a bag-shaped or tubular heat-resistant and easily peelable porous film is provided between the stock solution atomizer in the upper chamber and the corresponding powder product recovery device. A spray-drying apparatus comprising a spray-drying chamber configured in a detachable manner.