JP2587059B2 - Spray dryer with built-in fluidized bed - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention integrates a fluidized bed at the bottom of a spray-drying device to finish-dry, granulate or coat a spray-dried powder. The present invention relates to a spray drying apparatus with a built-in fluidized bed.

[Prior Art] Conventionally, as a spray drying apparatus with a built-in fluidized bed, an apparatus as shown in FIG. 3 is known.

In this apparatus, the undiluted solution A is sprayed by a spraying means 1 such as a nozzle.
The hot air B for spray drying is also blown into the spray drying section 3 from around the spray drying section 3 at the same time, and the stock solution A immediately becomes powder.
On the other hand, the powder obtained in the spray drying section 3 is subjected to finishing drying, granulation or coating in a fluidized bed section 4 provided at the lower portion of the apparatus main body 2 by a fluidized bed hot air C blown from below. Processing according to the purpose will be performed.

The hot air B for spray drying blown into the apparatus main body 2
The gas mixture of the hot air C and the fluidized bed hot air C is exhausted from the upper part of the apparatus main body 2, separated from the fine powder by the cyclone 5 and discharged to the outside air, and the fine powder D is returned to the apparatus main body 2.

[Problems to be Solved by the Invention] However, in the conventional device, as described above,
The mixed gas of the hot air B for spray drying and the hot air C for the fluidized bed was exhausted from the upper part or the middle part of the apparatus. At that time, gas drift occurred in the apparatus, and the main body of the apparatus remained undried. The problem of sticking to the wall of the car occurred.

Further, the fine powder entrained in the exhaust gas and collected by the cyclone 5 had to be returned to the apparatus by a conveyor or pneumatic transportation in the case of granulation or coating.

[Means for Solving the Problems] In order to solve the above-mentioned drawbacks of the conventional device, the present inventors have conducted intensive studies. As a result, by forming a part or all of the outer wall of the device with a porous membrane, The inventors have found that the disadvantage can be solved, and have reached the present invention.

That is, according to the present invention, an undiluted solution is sprayed on microdroplets, and a spray-drying unit for producing a powder by drying it with hot air is provided at the upper part, and the spray-dried part is manufactured at the lower part by the spray-drying unit. A fluidized bed built-in type spray-drying device provided with a fluidized bed of powder, wherein at least a part of an outer wall portion of the device is formed of a porous film, and a fluidized bed built-in type spray-drying device is provided. Is done.

It is preferable that the porous film used in the present invention has heat resistance and excellent peelability.

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 50 ° C at the outlet temperature. Since it is deposited, it needs to be of good peelability for continuous use. The porous membrane separates the target product fine powder from the gas.

The type of the porous membrane having such a function is not particularly limited, but a fiber cloth or a combination membrane of two or more of them is usually used. As a preferred porous film, a film obtained by laminating a woven fabric or a non-woven fabric as a strength material to a releasable mesh film is used. In this case, specifically, the mesh film is made of polytetrafluoroethylene (PTFE). As the (Teflon) -based film, the poly (trifluoroethylene) -based film, the woven fabric and the nonwoven fabric, those made of polyimide, heat-resistant nylon, polyester, and aramid are preferably used.

EXAMPLES Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a cross-sectional explanatory view showing one embodiment of a fluidized-bed built-in spray-drying apparatus of the present invention. The difference from the apparatus shown in FIG. 3 is that the outer wall of the apparatus is porous except for the top and bottom parts. That is, it is formed of the material film 6. In addition, since the outer wall of the apparatus is formed of the porous film 6, no powder entrainment occurs in the exhaust gas, and a cyclone for collecting fine powder and a line for the same as shown in FIG. 3 are not required. .

In the apparatus shown in FIG. 1, an undiluted solution A is blown into a spray-drying section 3 in an upper portion of the apparatus main body 2 by a spraying means 1 such as a nozzle, and hot air B for spray-drying is similarly sprayed from around the spray-drying section 3 And the stock solution A immediately becomes powder. On the other hand, the powder obtained in the spray drying section 3 is
In the fluidized bed section 4 provided at the lower part, a treatment according to the purpose such as finish drying, granulation or coating is performed by the fluidized bed hot air C blown from below.

As described above, the fluidized-bed built-in spray-drying apparatus shown in FIG. 1 is operated, but the gas such as the hot air blown into the apparatus is completely separated from the powder by the porous membrane 6. The turbulence and drifting of the gas do not occur, and the undiluted solution is prevented from adhering to the outer wall of the apparatus in an undried state. Further, since no powder is mixed into the exhaust gas, there is no need to collect fine powder by a conveyor or pneumatic transportation as in the related art.

Further, if the operation of the apparatus is continued, powder adheres to the porous film 6, and in this case, the adhered powder is wiped off by a vibration method or an air injection (air sweeper) method.

As the vibration method, in addition to the method of directly vibrating the porous membrane 6, as shown in FIG. 2, the vibration is transmitted from the vibrating fluidized bed 7 which vibrates the fluidized bed body itself, and the porous membrane 6 is vibrated. Can also.

As the spraying means 1 in the fluidized-bed built-in spray-drying apparatus of the present invention, conventionally known means can be used, and examples thereof include a disk type, a two-fluid nozzle body, and a pressure nozzle type.

Further, in the fluidized bed according to the present invention, as described above, a treatment according to the purpose such as finish drying, granulation or coating of the powder produced by spray drying is performed.

In the case of finish drying, the powder is dried for a certain period of time without spraying in the fluidized bed to achieve desired drying of the powder.

On the other hand, in the case of granulation, as shown in FIG. 2, dextrin, starch,
Binders such as gelatin, gum arabic, CMC, HPC,
The same or similar components as water or the liquid to be spray-dried are sprayed to granulate the powder.

Further, in the case of coating, the powder is coated with a color coat, a taste coat, a sustained release coat, and the like, and a product is manufactured for each use.

In the case of a substance that is highly hygroscopic and easily blocks, such as an amino acid, it is preferable to provide a stirring means in the fluidized bed and stir the fluidized bed.

Example A fluidized-bed built-in spray-drying apparatus having the shape and dimensions shown in FIG. 4 and having a funnel-shaped part formed of a porous membrane, and having an amino acid seasoning having a concentration of 40% by weight as a stock solution. To
30 kg / Hr, 1.8 kg / Hr of the same liquid as the stock solution as the binder liquid
At a rate of As the porous film, a combination film in which polytetrafluoroethylene was laminated on a heat-resistant nylon nonwoven fabric was used. The inlet temperature of the hot air for spray drying is 210
° C, inlet temperature of hot air for fluidized bed is 70 ° C, exhaust gas temperature is 75 ° C
° C.

The porous membrane was vibrated at a frequency of 1500 / min by an eccentric motor (not shown).

Exercise under the above conditions showed that the granulated product had an average particle size of 100-150 microns and a recovery of 97%.

Further, almost no powder adhered to the apparatus, and the fine powder hardly came out of the system.

(Comparative Example) The operation was performed under the same conditions as in the example except that the entire apparatus was made of steel.

As a result, the average particle size of the granulated product was 100 to 150 microns, but the recovery was 75%.

In addition, a large amount of undried particles adhered to the upper part of the apparatus, particularly in the vicinity of the exhaust port, and further, powder accumulation occurred on the funnel-shaped part of the apparatus.

[Effects of the Invention] As described above, according to the spray-drying apparatus with a built-in fluidized bed of the present invention, part or all of the outer wall of the apparatus is formed of a porous membrane, so that gas drift and turbulence occur in the apparatus. There is an advantage that the powder does not occur, powder is hardly attached to the inside of the apparatus, and fine powder is not entrained outside the system.

[Brief description of the drawings]

1 is a cross-sectional explanatory view showing one embodiment of the present invention, FIG. 2 is a cross-sectional explanatory view showing another embodiment of the present invention, FIG. 3 is a cross-sectional explanatory view showing an example of a conventional apparatus, and FIG. FIG. 3 is an explanatory diagram showing the shape and dimensions of an example of a spray-drying apparatus with a built-in fluidized bed. 1 ... spraying means, 2 ... apparatus main body, 3 ... spray drying section,
4 ... fluidized bed section, 5 ... cyclone, 6 ... porous membrane,
7: Vibrating fluidized bed.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-11632 (JP, A) JP-A-62-152502 (JP, A) JP-A-62-152501 (JP, A) JP-A 63-152501 59301 (JP, A) Fully open sho 56-126402 (JP, U) Fully open sho 55-44380 (JP, U) Really open sho 61-257229 (JP, U)

Claims (2)

(57) [Claims] 1. A spray drying section for spraying an undiluted solution into fine droplets and drying it with hot air to produce a powder is provided at an upper portion, and a powder produced by the spray drying section is provided at a lower portion. A fluidized-bed built-in spray-drying apparatus comprising: a fluidized-bed built-in type, wherein at least a part of an outer wall portion of the apparatus is formed of a porous membrane. 2. A spray-drying apparatus with a built-in fluidized bed according to claim 1, wherein a stirring means is provided in the fluidized bed.