JP3078588B2 - Fountain type nozzle device and spray dryer device incorporating it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fountain type nozzle device,
Its fountain-type nozzle apparatus spray dryer apparatus incorporating, further drying heat Kazemata relates spray dryer apparatus having a closed system that uses the spent exhaust in gas for blowing a high velocity gas.

[0002]

2. Description of the Related Art Generally, in a spray dryer, a nozzle device is arranged downward at the upper part of a drying chamber, and the liquid is blown downward to spray the liquid, and the liquid is brought into contact with hot air from the upper part to be dried and solidified. I have. This is because it was considered that the blowing of the liquid was less turbulent and more effective if it followed gravity downward. In addition, as a hot air used for drying and a gas for blowing high-speed gas, an open system in which a gas having desired physical properties is newly supplied and used is usually adopted.

[0003]

However, when it is desired to obtain a powder product having a large average particle size or a dried product of a substance having a large specific gravity, for example, granulation of large ceramic particles having an average particle size of 150 μm or a large specific gravity is required. P containing lead compounds
In granulation of ZT ceramics or the like, it is necessary to lengthen the drying time and perform drying sufficiently, and this cannot be ensured in the downward type. In addition, if a flammable solvent is used in the stock solution, there is a risk of fire or explosion, and substances that easily oxidize when dried in the air need to be protected from oxidation.If the exhaust contains odor, from the viewpoint of pollution prevention It is necessary to prevent the emission of offensive odors, and in the case of expensive and toxic solvents it is necessary to recover.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a solution which is difficult to dry: even a heavy solution or large liquid particles. A fountain type nozzle device capable of atomizing the droplets by extending the residence time in the drying chamber and completely drying the droplets, further performing air blowing outside the spray nozzles, further cooling the piping, and preventing clogging of the undiluted solution, and the like. It is an object of the present invention to provide a spray dryer device provided with the above. Furthermore, fire and explosion prevention, oxidation of the liquid, pollution control, blowing a high speed gas also by a closed system from the point of view of resource recovery is intended to provide a circulating supply spray dryer apparatus for drying hot air.

[0005]

In order to achieve the above object, the present invention provides a pressure swirl nozzle for discharging a stock solution,
A pressurized two-fluid nozzle comprising a high-speed gas blowing tubular body provided around the pressure swirling nozzle, wherein a tip of the pressurized two-fluid nozzle has a tapered structure, and the high-speed gas blowing is performed.
Preventing the powder adheres to the side surface (the nozzle cone) in use cylindrical body tip
And a fountain type nozzle device provided with an air purge hole for the nozzle.

[0006] According to the present invention consists of a pressure swirl nozzle for blowing stock solution, the high-speed gas blowing tubular body provided around the pressure swirl nozzles, and the tip end tapered structure, and the Side of tip of cylindrical body for high-speed gas blowing
A pressurized two-fluid nozzle device provided with an air purge hole for preventing powder adhesion is disposed upward in the lower part of the drying chamber, and a hot air blowing port into the drying chamber and a lower part are provided in the upper part.
Spray dryer apparatus comprising the outlet from the drying chamber is provided. The invention further heat Kazemata to the drying chamber is intended to provide a spray dryer apparatus for supplying a gas for blowing high-speed gas, a closed system for recycling all or a portion of the spent exhaust spray drying is there.

[0007]

The liquid ejected upward from the fountain type nozzle device (or pressurized two-fluid nozzle device) rises and falls along a parabolic trajectory. The residence time can be doubled, and the drying time can be doubled. Since the fountain type nozzle device (or pressurized two-fluid nozzle device) is arranged upward at the lower part of the drying chamber,
Since the flowers bloom phenomena may fall and come dry powder droplets or adhered is dried and solidified at the nozzle device upper part can occur, in this case, high-speed gas blowing tubular body tip side of the (nozzle cone ) Is provided with a hole for air purge, and is removed by air purge. In the example, when using a flammable solvent to concentrate, dry heat Kazemata gas for blowing high-speed gas reusing spent gas by a closed system.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the illustrated embodiments, but it will be apparent that the present invention is not limited to these embodiments. FIG. 1 is an explanatory sectional view showing an embodiment of a spray dryer device incorporating a nozzle device of the present invention, FIG. 2 is a partial sectional view showing a tip portion of the nozzle device of FIG. 1, and FIG. And FIG. 4 is a schematic diagram showing an example of a semi-closed system of a spray dryer device.

1 and 2, reference numeral 1 denotes a spray drier device, 2 denotes a nozzle device, 3 denotes a jacket pipe,
Denotes an air nozzle, 5 denotes a stock solution (or water) pipe, 6 denotes a pressure swirling nozzle for blowing out the stock solution (or water), 7 denotes a drying chamber, and 8 denotes an air purge hole. That is, in the nozzle device 2 of the present invention, a jacket pipe 3 is provided around a stock solution pipe 5 for blowing stock solution or water, and a pressure swirling nozzle 6 and an air nozzle 4, which are the blowing end portions, as shown in FIG. In addition, the diameter decreases as it goes
It has a so-called tapered structure, and has an air purge hole 8 on the side surface of the jacket pipe 3.

[0010] The nozzle device 2 is disposed upward in the lower part of the drying chamber 7 of the spray dryer device 1. For this reason, the liquid is blown up in a parabolic manner from below and is dropped. Therefore, it is possible to obtain about twice the drying time as compared with the downward blowing. Here, the spray pressure of the undiluted solution or water at the pressure swirl nozzle 6 relates to the following general formula representing the outflow characteristics of the pressure nozzle, and the droplet diameter of the pressure nozzle used (in this case, SX nozzle, Spraying). It is determined appropriately according to the formula. W (kg / h) = K ₁ · D ² (mm) · P ^0.5 (kg / cm ² ) ... (W: throughput, K ₁ : coefficient, D: orifice diameter, P: pressure) D _P (μm) = K ₂ · W ^-0.44 (kg / h) · µ ^0.16 (cp) · D ^1.52 (mm) ··· (W: throughput, D _P : droplet diameter, K ₂ : coefficient, µ: liquid viscosity)

In the air nozzle 4 provided around the pressure swirl nozzle 6, the air blowing speed is 80 m / s or more, preferably 100 m / s or more when spraying water, and the air pressure is generally 0.1 kg / cm. ² or more, preferably 0.2 kg / cm ² or more. When the stock solution is sprayed, the blowing speed is reduced from one half to several tens of minutes, but it is not limited to this. May be used outside the above numerical range. Next, the operation of the spray dryer will be described with reference to FIG. 3, which shows an example of a closed system of a spray dryer incorporating the nozzle device of the present invention. First, at the start of operation, water or a solvent is sprayed from the pressurized tank 31 through the stock solution pipe 5 by the pressure swirling nozzle 6. In this case, the spray becomes a considerably low-pressure spray, but air is blown upward at high speed from around the pressure swirl nozzle 6. Then, the water droplet is atomized to a desired droplet diameter.

When the water droplets are atomized to a desired diameter in this way, the hang time is about twice as long as the downward blowing, so that the hot air A blown into the drying chamber 7 of the spray drier 1 completely removes the water droplets. To be dried. Then, without drying water remaining in the drying chamber 7,
The temperature distribution in the drying chamber 7 is almost eliminated, that is, the temperature in the drying chamber 7 can be kept constant. Next, into the drying chamber 7 of the spray drier 1, the stock solution L corresponding to a predetermined purpose is blown upward from the lower part of the drying chamber 7 via the pressure swirl nozzle 2 of the nozzle device, and the surroundings of the pressure swirl nozzle 6 When the operation is performed with a small amount of air by squeezing the amount of air, the diameter of the droplet increases, and a predetermined powder product can be obtained. In this case, since the nozzle device 2 faces upward, there is a possibility that powder particles of the product adhere to the vicinity of the head of the nozzle device 2. However, the powder particles are removed by air purging from an air purging hole 8 provided on the side surface of the jacket pipe 3. can do.

In the case where the stock solution L is sprayed by the nozzle device 2, flowing a small amount of air around the pressure swirling nozzle 2 through the air nozzle 4 cools the nozzle device 2 and blocks the stock solution. This is preferable because it can prevent the occurrence of the Next, the closed cycle of the spray dryer will be described. The undiluted solution L supplied from the pressurized tank 31 is blown upward from the nozzle device 2 in the drying chamber 7 of the spray dryer device 1 and dried by hot air A sent from above while falling in a parabolic manner. Then, it is collected as a granulated product 33 below. On the other hand, the hot air A is cooled by exchanging heat with the granulated product 33 and sent to the cyclone 34 through a pipe from an opening provided on the side surface of the spray dryer device 1 to separate gas and solid. Further, impurities are filtered by a bag filter 35, then liquefied by an indirect condenser 36, sent to a heater 39 by a circulation blower 38, heated to a required temperature, and reused.

Next, the semi-closed cycle of the spray dryer will be described with reference to FIG.
The air sent from the combustion blower 41 burns the fuel 42 in a direct-fired furnace 45, and the resulting hot air composed of the heated exhaust gas is sent to the lower part of a drying chamber 47 of the spray dryer 1. Then, it is guided from the top of the spray dryer device 1 to the exhaust pipe 56. Meanwhile, spray dryer device 1
Pressurized two-fluid nozzle 2 arranged downward at the top of
The liquid spray formed by blowing from is dried and solidified.
The dried and solidified product 48 is collected below, and the hot air that has been dried and solidified is guided to the exhaust pipe 56 as exhaust gas. Then, the solid in the exhaust gas is separated from the gas by the cyclone 49, the fine powder is removed by the bag filter 51, and sent to the scrubber 54 by the circulation blower 53. The scrubber 54 removes impurities by passing exhaust gas through the liquid,
It is sent to the roots blower 43 and the dilution fan 44.
The exhaust gas sent to the roots blower 43 is reused for high-speed gas blowing when a pressurized two-fluid nozzle is used as the nozzle device 2.

The exhaust gas sent to the dilution fan 44 is:
It is reheated in the direct fire furnace 45 and reused as hot air for drying. As a gas used in a closed system and a semi-closed system, a closed system is preferable for preventing fire, explosion, and oxidation.
Inert gases such as ₂ , Ar, and CO ₂ are optimal. A semi-closed system is preferable for the CO ₂ rich gas of the combustion exhaust gas. Similarly, fire, explosion and oxidation can be prevented. A closed system using air is effective in preventing odor emission.

Hereinafter, specific embodiments will be described. (Example 1) For granulation of a slurry in which a cemented carbide (WC + Co) powder is dispersed in ethanol, N2 gas is used for drying in order to prevent oxidation of the cemented carbide and fire and explosion due to ethanol, Spray drying of the closed system with full circulation was performed. The spraying method adopts the pressurized two-fluid nozzle shown in Fig. 2 and is used as atomizing gas when spraying only the solvent (ethanol) at startup and shutdown, and adhesion and deposition of product powder and particles on the upper part of the nozzle For the purpose of prevention, the gas amount was halved and the internal circulation gas was used. The nozzle used is an SX nozzle (orifice diameter 1.06 mm, core type 425) manufactured by Spraying System.

The operating conditions are shown below. Stock solution name Cemented carbide and ethanol slurry Same solid content 80% Same viscosity 300 cps Drying chamber diameter 3m 〃 Straight body height 3.5m 〃 Conical part height 2.6m Hot air N ₂ gas Same O ₂ concentration 1 vol.% Hot air temperature 180 ° C Exhaust temperature 70 ° C Liquid flow rate when spraying undiluted liquid 150 kg / h Liquid flow rate when spraying solvent 30 kg / h Hot air flow rate 1100 Nm ³ / h Gas flow rate to nozzle part when spraying undiluted liquid 10 Nm ³ / h Solvent spray Gas flow to the nozzle at the time 20 Nm ³ / h Liquid pressure at the time of spraying undiluted solution 10 kg / cm ² Liquid pressure at the time of solvent spraying 5 kg / cm ² Product average particle diameter 145 μm

Under the above operating conditions, even in the case of spraying only the solvent, the liquid is atomized, so that the wall of the drying chamber did not get wet, and there was no clogging in the piping because the solvent was sprayed after the end of the undiluted solution spraying. Further, since the N ₂ gas in the system was circulated as the gas for atomizing the nozzle, an increase in the O ₂ concentration in the system could be prevented. Thus, since the recycling of the system in the gas to the nozzle portion in the present embodiment, as compared with the case of using the new N ₂ gas, when the stock solution spray 10 Nm ³ / h, at the time of solvent only spray 20 Nm ³ / h, New N ₂ gas was saved.

(Example 2) In the drying of pesticides, for the purpose of preventing burning and fire in a drying room, a heat source of a kerosene direct fire system is used, and CO is discharged by a semi-closed system of exhaust gas.
It was carried out by spray drying _2, N ₂ gas rich hot air. As the spraying method, a pressurized two-fluid nozzle having no air purge hole in the structure shown in FIG. 2 was employed, and an in-system circulation gas was used as the atomizing gas. Since the hot air was rising from below, the nozzle was placed at the top of the drying chamber and sprayed downward. That is, like the fountain type, the hot air and the spray direction were arranged in countercurrent.

The operating conditions are shown below. Stock name Pesticide (main component + water + surfactant) Same solid content 50% Same viscosity 3000 cps Drying room Diameter 2.2m 〃 Straight body height 6m 〃 Conical height 2m O2 concentration in system 3% or less Hot air temperature 200 ° C Exhaust temperature 85 ° C Liquid flow rate when spraying stock solution 250 kg / h Liquid flow rate when spraying water 120 kg / h Hot air flow rate 2400 Nm ³ / h Gas flow rate to nozzle section when spraying stock solution 200 Nm ³ / h; Gas pressure 0.25 kg / cm ² Gas flow to the nozzle during water spraying 200 Nm ³ / h; Gas pressure 0.25 kg / cm ² Fluid pressure when spraying undiluted solution 20 kg / cm ² Fluid pressure when spraying water 5 kg / cm ² Nozzle SX Type (Spray Ink System Co., Ltd.) Orifice Diameter 1.7mm 式 〃 コ ア Core Model 425 Product Average Particle Size 70 μm

Under the above operating conditions, the atomization is stabilized even when only water is sprayed, so that the wall surface of the drying chamber does not get wet, and the operating conditions become stable immediately after the start of operation.
There was no thermal deterioration of the product. If the gas inside the system is not circulated and used for the nozzle part but outside air is used, the O
₂ concentration is O ₂ concentration from hot air O ₂ gas amount from hot air 2400 × 0.04 = 96 Nm ³ / h O ₂ gas amount from atomizing air 200 × 0.2 = 40 Nm ³ / h , The average is (96 + 40) / (2400 + 200) =
It becomes 5.2%, which leads to an increase in the O ₂ concentration in the system, which is not desirable.

[0022]

As described above, in the fountain type nozzle device of the present invention, since the liquid is blown upward from the lower part of the drying chamber, the residence time of the liquid in the drying chamber becomes longer, and therefore the drying time also becomes longer. It becomes longer and can be dried sufficiently.
Further, it can be removed by providing a hole for purging the product attached to the nozzle device. When hot air is introduced from below, it is effective to install the nozzle downward. Furthermore, the closed system spray drier according to the present invention can be used for fire and
It is effective for preventing explosion or solute oxidation of stock solution, preventing odor emission, and recovering expensive or harmful solvents.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an embodiment of a spray drier device incorporating a nozzle device of the present invention.

FIG. 2 is a partial cross-sectional explanatory view showing a tip portion of the nozzle device of FIG. 1;

FIG. 3 is a schematic view showing an example of a closed system of the spray dryer of the present invention.

FIG. 4 is a schematic view showing an example of a semi-closed system of the spray dryer.

[Explanation of symbols]

 Reference Signs List 1 spray dryer device 2 nozzle device (pressurized two-fluid nozzle) 3 jacket pipe 4 air nozzle 5 undiluted (or water) pipe 6 pressure swirl nozzle 7 drying chamber 8 air purge hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-194901 (JP, A) JP-A-61-192364 (JP, A) JP-A-58-63001 (JP, U) JP-A-2-62 12464 (JP, U) JP 56-41566 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05B 7/10 B01D 1/20

Claims (4)

(57) [Claims] 1. A pressure swirl nozzle for discharging a stock solution,
A pressurized two-fluid nozzle comprising a high-speed gas blowing tubular body provided around the pressure swirling nozzle, wherein a tip of the pressurized two-fluid nozzle has a tapered structure, and the high-speed gas blowing is performed.
A fountain type nozzle device characterized in that an air purge hole for preventing powder adhesion is provided on a side surface of a tip portion of a tubular body for use . 2. A pressure swirl nozzle for discharging a stock solution,
A high-speed gas blowing tubular body provided around the pressure swirl nozzle, the tip of which is tapered ,
To prevent powder adhesion on the side of the tip of the cylindrical body for rapid gas blowing
A pressurized two-fluid nozzle device provided with an air purge hole is disposed upward at the lower part of the drying chamber, and a hot air blowing port into the drying chamber is provided at the upper part and an exhaust port from the drying chamber is provided at the lower part. A spray dryer device comprising: 3. The spray dryer according to claim 2, wherein the hot air into the drying chamber is supplied by a closed system which circulates and uses all or a part of exhaust air used for spray drying. 4. The spray dryer according to claim 2, wherein the gas for blowing high-speed gas is supplied by a closed system that circulates and uses all or a part of exhaust gas used for spray drying.