JP2018143995A - Spray fine particle manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for suppressing or removing attachment generation to a reaction tube inner wall without changing normal spray dry and spray pyrolysis conditions in a reaction tube.SOLUTION: There is provided a spray fine particle manufacturing device having a reaction tube 1, a nozzle 2 for spraying raw material liquid fixed on an upper part of the reaction tube 1, a heating source 3 set on a periphery of the reaction tube 1, and a fine particle collection device 4 connected from a lower part of the reaction tube 1 with a pipe, and also having a rotation type structure in which a blade 5 rotating by wind from an upper part and a scraping rod 6 rotating in contact with a reaction tube 1 inner wall in conjunction with movements of the rotating blade 5 are connected at a center position of a circle cross section in a horizontal direction in the reaction tube 1. There is provided a spray fine particle manufacturing device in which wind is generated from the upper part to the lower part of the reaction tube 1 by an aspiration means of an aspirating fine particle collection device 4 at the lower part of the reaction tube 1, the blade 5 is rotated and it is preferable that the lower part of the reaction tube 1 has a taper structure and further has a rotation type structure having the blade 5 and the scraping rod 6 same as an intermediate part.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an apparatus for producing fine particles by spray drying or spray pyrolysis.

The spray drying method or spray pyrolysis method is a method in which a raw material liquid is sprayed from a nozzle at the top of a reaction tube and dried or thermally decomposed by heating inside the reaction tube to produce fine particles. This apparatus basically has a structure having a nozzle at the upper part of the reaction tube, a heat source at the outer periphery of the reaction tube, and collecting fine particles generated from the lower part of the reaction tube.
The raw material droplet sprayed by the nozzle diffuses in a conical shape from the nozzle tip. The powder containing moisture may adhere to and deposit on the inner surface of the reaction tube and the conical part depending on conditions such as the amount of gas in the reaction tube, the form of spray pattern, the heating temperature, and the amount of stock solution. This adhesion / deposit reduces the thermal conductivity of the reaction tube and lowers the quality of the fine particles produced, and also causes clogging inside the reaction tube and hinders continuous operation.

  As a means for preventing the occurrence of deposits on the inner wall of the reaction tube, a technique for actively drying droplets by blowing hot air for drying from a peripheral outlet on the inner wall of the drying cylinder (Patent Document 1) The spray drying granulation apparatus having a spray drying part and a fluidized granulation part in one tank, and is directed downward or obliquely downward along the inner surface of the cone part near the upper end of the cone part of the spray drying part. (Patent document 2) including a means for introducing an airflow into the wall, a technique for suppressing the amount of deposits on the wall surface by blowing compressed gas into the wall surface from a cylindrical side surface (patent document 3), powder There has been reported a technique (Patent Document 4) for forming a cold air zone by introducing a cold gas around a body drying zone. In addition to the nozzle, a technique (Patent Document 5) that includes a rotary scraping mechanism having a rotating shaft at the center of the reaction tube has also been reported.

JP 2005-291530 A JP 2002-45675 A Japanese National Patent Publication No. 7-506530 JP 63-267401 A JP 2010-42934 A

  In the techniques of Patent Documents 1 to 4, all the air is blown into the reaction tube. By blowing air, the flow rate varies between the side surface and the central part, or the amount of air to be exhausted increases. This makes it difficult to control the particle size and causes variations in the physical properties of the particles. Moreover, in the technique of patent document 5, since the rotational drive shaft is installed at the center of the upper end of the reaction tube, it is necessary to shift the nozzle position from the center. When the position of the nozzle deviates from the center, the spray pattern of the raw material droplets in the reaction tube does not become a contrasting shape, and uniform heat is not applied to the droplets, resulting in variations in products. In addition, the droplets are more likely to adhere to the wall surface.

  Accordingly, an object of the present invention is to provide means for suppressing or removing the generation of deposits on the inner wall of the reaction tube without changing any of the usual spray drying and spray pyrolysis conditions inside the reaction tube.

  Therefore, as a result of various studies, the inventor can suppress the occurrence of deposits on the inner wall of the reaction tube by installing a rotating blade and a scraping bar that rotates in conjunction with the rotation blade at the center of the reaction tube, and It has been found that fine particles can be produced stably and efficiently because it does not cause a large change in the temperature and flow rate inside the reaction tube, and the present invention has been completed.

  That is, the present invention provides the following inventions [1] to [3].

[1] Sprayed fine particles equipped with a reaction tube, a raw material liquid spray nozzle fixed to the upper part of the reaction tube, a heating source installed on the outer periphery of the reaction tube, and a particulate collection device connected by piping from the lower part of the reaction tube A manufacturing apparatus, a blade that rotates when wind hits the center position of a horizontal circular cross section inside the reaction tube, and a scraper that rotates in contact with the inner wall of the reaction tube in conjunction with the movement of the rotating blade. An apparatus for producing atomized fine particles, comprising: a rotary structure to which a dropping rod is connected.
[2] The atomized fine particle production apparatus according to [1], wherein a wind from the upper part to the lower part is generated in the reaction tube by the suction means of the attractive particle collecting device at the lower part of the reaction tube.
[3] The spray particle production apparatus according to [1] or [2], wherein a lower part of the reaction tube has a taper structure, and the rotary structure is further provided in the taper structure part.

  In the apparatus of the present invention, since the rotating structure is installed in the reaction tube, it does not interfere with the nozzle position. In addition, it does not require external power such as a motor to drive the rotation, and rotates only with the gas wind pressure in the furnace, so that costs such as electricity costs can be reduced. In addition to scraping off, the flow of air can be formed from the blades to the inside of the reaction tube by inclining the rotating blades, so that the effect of preventing adhesion can be obtained.

The schematic of this invention spray fine particle manufacturing apparatus is shown. The top view (left) and front view (right) of a rotating structure are shown. The schematic of the conventional spraying fine particle manufacturing apparatus is shown. A schematic view of an atomized fine particle manufacturing apparatus in which a rotating structure is also installed in the lower part of the reaction tube is shown. The schematic of the conventional spraying fine particle manufacturing apparatus is shown.

  An embodiment of an atomized fine particle manufacturing apparatus of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the spray fine particle production apparatus of the present invention comprises a reaction tube 1, a raw material liquid spray nozzle 2 fixed to the upper part of the reaction tube, a heating source 3 installed on the outer periphery of the reaction tube, and a reaction tube. A particulate collection device 4 connected by piping from below is provided.

  The reaction tube 1 is a reaction furnace in which droplets sprayed from the nozzle 2 are heated to dry or heat to form fine particles and move to the lower part of the reaction tube. For example, if a mixed solution of aluminum nitrate and tetraethyl orthosilicate is sprayed from the nozzle 2 and heated to 400 ° C. to 800 ° C., aluminosilicate hollow particles can be obtained. The reaction tube 1 is usually cylindrical and is made of a metal such as stainless steel, a high nickel alloy, an Inconel alloy, or a ceramic such as mullite or alumina.

  As the raw material liquid spray nozzle 2 fixed to the upper part of the reaction tube, a two-fluid nozzle or a four-fluid nozzle can be used. The raw material solution is supplied to this nozzle through a pump. Here, the two-fluid nozzle method includes an internal mixing method in which air and the solution are mixed inside the nozzle, and an external mixing method in which the air and the solution are mixed outside the nozzle.

  A heating source 3 is provided on the outer periphery of the reaction tube. The heating source 3 may be a heater that can form a temperature range in which the mist sprayed from the nozzle 2 can be dried or thermally decomposed, and may be a heating source by gas combustion or an electric heater.

  At the lower part of the reaction tube, an attracting particulate collection device 4 connected by piping from the lower part of the reaction tube is provided. As the suction particulate collection device 4, a high-performance cyclone powder recovery machine or a bag filter can be used. Further, the collection of fine particles can be adjusted by performing a classification operation such as passing through a filter.

  As shown in FIGS. 1, 2 and 4, the apparatus of the present invention comprises a vane 5 that rotates when wind strikes the center position of a circular cross section in the horizontal direction inside the reaction tube 1 from above. The rotary structure is connected to the scraping rod 6 that rotates in contact with the inner wall of the reaction tube in conjunction with the movement of the rotating blades.

The rotary blade 5 is installed at the center position of the horizontal circular cross section inside the reaction tube (FIGS. 1 and 2). In installing the rotary blade 5, it is preferable to use a wheel-like fixing mechanism 7 disposed so as to be in contact with the inner wall of the reaction tube. The wheel-like fixing mechanism 7 preferably has a shape having a small area so as to have only a fixing function of the rotating blades at the center and not to hinder movement of particles and the like. The rotating blade is installed at the center position of the wheel-like fixing mechanism 7. By installing the rotary blade 5 at the center position of the circular cross section in the horizontal direction inside the reaction tube, the droplets sprayed from the nozzle 2 can be distributed throughout the reaction tube.
Moreover, the rotary blade 5 is installed so as to rotate when wind hits from the upper part. By installing in this way, for example, the rotating blade 5 rotates without requiring any power under the condition that the lower part of the reaction tube becomes a negative pressure by the cyclone powder recovery machine of the suction particulate collection device. The number of rotating blades is preferably 3 to 6, more preferably 3 to 4, and particularly preferably 4.
Further, if the rotary blade is provided with an inclination, an air flow can be formed from the blade to the inside of the reaction tube, and an adhesion preventing effect can be obtained.

  A scraping rod 6 that rotates in contact with the inner wall of the reaction tube in conjunction with the movement of the rotary blade is connected to the rotary structure. The scraping bar 6 may have a structure that can rotate in contact with the inner wall of the reaction tube in order to scrape off deposits adhering to the inner wall of the reaction tube, and the shape is not limited. Preferably, it attaches to the front-end | tip part of a rotary blade like FIG. Moreover, it is preferable that the scraping bar 6 is the same as the number of the rotary blades.

  The rotational position of the rotary structure may be within the reaction tube, but a position where droplets sprayed from the nozzle are likely to adhere, that is, the upper portion of the reaction tube is more preferable. Moreover, the said rotary structure may be further installed in the taper structure part of the reaction tube lower part like FIG. By installing at the lower part of the reaction tube, it is possible to prevent adhesion of fine particles to the site as shown in FIG.

  Next, the effects of the present invention will be described with reference to examples.

Example 1
As shown in FIG. 2, the rotary structure was installed in the reaction tube of the fine particle production apparatus. Next, a mixed aqueous solution of aluminum and silicon in which 0.04 mol of aluminum nitrate and 0.16 mol of tetraethyl orthosilicate were dissolved in 1 liter of distilled water was charged into the solution tank. The introduced aqueous solution was sprayed in the form of a mist through a two-fluid nozzle by a liquid feed pump, and passed through a drying zone (about 400 ° C.) and then a thermal decomposition zone (800 ° C.). Hollow particles were collected using a bag filter. The obtained hollow particles were fired at about 1000 ° C. to obtain the intended aluminosilicate hollow particles.
Thereafter, when the inner wall of the reaction tube was confirmed, no deposits or deposits were confirmed.

Comparative Example 1
A spray test similar to that in the above example was performed with a conventional fine particle production device. As a result, adhesion and deposits were confirmed near the intersection of the mist injection angle and the reaction tube, and near the tapered portion under the reaction tube. (FIGS. 3 and 5).

DESCRIPTION OF SYMBOLS 1 Reaction tube 2 Nozzle 3 Heating source 4 Particulate collection device 5 Rotary blade 6 Scraping rod 7 Wheel-shaped fixing mechanism

Claims (3)

  A spray particle production device equipped with a reaction tube, a nozzle for spraying the raw material liquid fixed to the upper part of the reaction tube, a heating source installed on the outer periphery of the reaction tube, and a particle collecting device connected by piping from the lower part of the reaction tube A blade that rotates when the wind hits the center position of the horizontal circular cross section inside the reaction tube, and a scraping rod that rotates in contact with the inner wall of the reaction tube in conjunction with the movement of the rotating blade. An apparatus for producing atomized fine particles, characterized in that it comprises a rotary structure to which is connected.   2. The atomized fine particle manufacturing apparatus according to claim 1, wherein a wind from the upper part to the lower part is generated in the reaction tube by the suction means of the suction particle collecting device at the lower part of the reaction tube.   The spray particle production apparatus according to claim 1 or 2, wherein a lower part of the reaction tube has a tapered structure, and the rotary structure is further provided inside the tapered structure part.

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