JP2007083111A - Powder production apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder production apparatus in which upper and lower variation of a pressure at the inside of a power production column by a flame spray pyrolysis is small. <P>SOLUTION: The powder production apparatus 1 has an air-tightly closed cylindrical powder production column 2; a spraying means 3 for spraying an aqueous material solution into the inside of the powder production column 2; a conveying gas flow passage 5 for feeding a conveying gas from a periphery of the spraying means 3 to the inside of the powder production column 2; a flame injection nozzle 7 for injecting the flame to the inside of the powder production column 2; and an exhaust apparatus for discharging a gas in the powder production column 2 therefrom. An outside air flow passage 18 released to the outside is provided on a negative pressure part 16 becoming a negative pressure relative to the outside in the steady state of the conveying gas flow passage 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a powder production apparatus using a flame spray pyrolysis method.

For example, as a method for producing a powder as a raw material for a battery electrode, as described in Patent Documents 1 to 3, for example, an aqueous solution of a powder raw material is sprayed in a powder forming tower and dried and heated by a flame. Methods for decomposing are known.
JP 2004-292223 A JP 2005-183004 A US Patent No. 3230064 Specification

  The conventional powder production apparatus described in Patent Documents 1 to 3 includes a cylindrical powder production tower, spraying means for spraying the raw material aqueous solution inside the powder production tower, and a flame in the powder production tower. And a plurality of flame injection nozzles and an exhaust fan for extracting water vapor evaporated from the aqueous solution and the generated powder together with air from the powder generation tower. Further, the conventional powder manufacturing apparatus supplies a carrier gas (generally air), which is transported to the high temperature portion of the flame by spraying the mist of the sprayed aqueous solution and is drawn out by the exhaust fan from the periphery of the spray device.

  The spraying of the aqueous solution by the spraying means separates the aqueous solution into small diameter mists by the balance of surface tension with the carrier gas. However, it is difficult to keep the balance of the surface tension between the aqueous solution, which is a high-speed fluid, and the carrier gas constant, and when the balance is lost, the spray mist causes an unsteady and rapid flow rate fluctuation called “breathing”. When the amount of sprayed mist fluctuates up and down, the amount of water vapor that evaporates also fluctuates up and down, and the pressure inside the powder production tower fluctuates up and down.

  The increase in the internal pressure of the powder generation tower causes a decrease in the pressure difference between the fuel or combustion air injected from the flame injection nozzle and the internal pressure of the powder generation tower, leading to a decrease in the flow rate of the fuel or combustion air. There was a problem of causing misfire and hindering production.

  Then, in view of the said problem, this invention makes it a subject to provide the powder manufacturing apparatus with a small pressure up-and-down fluctuation inside a powder production tower by a flame type spray pyrolysis method.

  In order to solve the above problems, a powder production apparatus according to the present invention includes a sealed cylindrical powder production tower, spraying means for spraying a raw material aqueous solution inside the powder production tower, and the powder production tower. A carrier gas flow path for supplying a carrier gas from the periphery of the spraying means, a flame injection nozzle for injecting a flame into the powder production tower, and the powder production tower. The carrier gas flow path is provided with an external air flow path that is open to the outside in a negative pressure portion that is negative with respect to the outside in a steady state. .

  According to this configuration, outside air is constantly introduced from the outside air flow path. The flow rate of the outside air introduced from the outside air flow path changes according to the change in the internal pressure of the powder generation tower, but the flow rate of the outside air when the internal pressure decreases (negative pressure increases) due to the flow path resistance of the outside air flow path. However, when the internal pressure increases (the negative pressure becomes small or becomes positive), the flow resistance of the external air flow path is small, and the flow rate of the external air tends to decrease. For this reason, when the internal pressure of a powder production tower rises, the external air introduce | transduced decreases and the effect | action which tries to return an internal pressure to a steady state becomes strong, and suppresses an excessive internal pressure rise. Thereby, misfire of the flame injection nozzle can be prevented.

  If the exhaust device includes a flow rate control means for controlling the flow rate of the gas discharged from the powder production tower, the amount of gas exhausted from the powder formation tower is constant. The balance point of crystallization is constant. Thereby, the internal pressure of the powder forming tower is stabilized.

  As described above, according to the present invention, since the outside air is taken in from the outside air channel having the channel resistance to the powder forming tower, the internal pressure fluctuation of the powder forming tower can be strongly suppressed on the pressure increase side, Misfire of the flame injection nozzle can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, the powder manufacturing apparatus 1 of 1st Embodiment of this invention is shown. The powder production apparatus 1 includes a powder production tower 2 which is a cylindrical upright metal container with both ends narrowed down, and a powder to be produced inside the powder production tower 2 from the upper end of the powder production tower 2. The spray (spraying means) 3 for spraying the aqueous solution that is the raw material of the above and the upper end of the powder generation tower 2 are sealed, and the air (carrier gas) supplied from the air supply fan 4 is sprayed from the periphery of the spray 3 to the spraying direction. Similarly, a sealing header 6 having a primary air flow path (carrier gas flow path) 5 for guiding it to be introduced downward, and a barrel wall of the powder generation tower 2, and a flame swirl by injecting a flame inside. A plurality of flame injection nozzles 7 that form a flow, a plurality of cooling nozzles 8 that are provided in the lower part of the body wall of the powder generation tower 2 of the flame injection nozzles 7, and a lower end of the powder generation tower 2 The exhaust passage 9 provided to extend from the exhaust passage 9 and the bag filter 10 from the exhaust passage 9 Exhaust fan is made from (exhaust device) 11 for exhausting by suction gas in the internal powder product column 2 in. The powder generation tower 2 is a sealed container that has both ends communicating with the primary air flow path 5 and the exhaust path 9 and provided with the flame injection nozzle 7 and the cooling nozzle 8, but is not directly opened to the atmosphere. The surface is covered with a heat insulating material 12. The exhaust passage 9 downstream of the bag filter 10 is provided with an orifice flow meter 13 and a throttle valve (flow control means) 14 that can adjust the flow rate of gas in the exhaust passage 9.

  As shown in FIG. 2, the primary air flow path 5 of the sealed header 6 includes a distribution unit 15 that distributes the air sent from the air supply fan 4 so as to surround the piping of the spray 3, and the spray 3. The negative pressure part 16 with a narrow flow path that folds back along the pipe of the pipe and the rectifying part 17 that guides air downward along the pipe of the spray 3. The negative pressure part 16 has a small diameter that is open to the atmosphere. An outside air flow path 18 including holes is provided (the air flow is indicated by a dashed-dotted arrow).

Then, the effect | action of the powder manufacturing apparatus 1 which consists of the above structure is demonstrated.
The powder manufacturing apparatus 1 heats the mist of the aqueous solution sprayed from the spray 3 by the flame of the flame spray nozzle 7 and generates a powder having a desired composition by dry pyrolysis. The powder generated by introducing cold air from the cooling nozzle 8 is cooled, and the powder generated together with the gas including air supplied from the primary air flow path 5 and water vapor evaporated from the mist is sucked by the exhaust fan 11. It exhausts from the exhaust path 9. The bag filter 10 separates and collects the powder from the discharged gas.

  According to Bernoulli's theorem, the air sent out at high pressure by the air supply fan 4 has a high flow velocity and a low pressure in the negative pressure portion 16 having a narrow flow path. For this reason, outside air is sucked from the relatively high-pressure outside air flow path 18 to increase the flow rate, and is introduced from the rectifying unit 17 downward into the powder generation tower 2 from the periphery of the spray 3. The air descends with the mist (droplet) of the aqueous solution sprayed by the spray, and becomes a hot swirling airflow by the flame of the flame injection nozzle 7.

  In order to prevent the powder from leaking, the powder production apparatus 1 uses the air supplied from the air supply fan 4 and the outside air flow path 18 so that the internal pressure of the powder generation tower 2 is slightly negative from the atmosphere. The exhaust air is exhausted from the exhaust passage 9 by the exhaust fan 11, the outside air introduced from the air, the water vapor evaporated from the aqueous solution sprayed by the spray 3, the combustion gas injected from the flame injection nozzle 7, and the amount of air introduced from the cooling nozzle 8. It operates on the condition which adjusted the quantity of the gas made. At this time, the total amount of gas exhausted is measured by the orifice flow meter 13, and the throttle valve 14 is adjusted to control the exhausted amount to be constant.

  During steady operation, the amount of water vapor evaporated from the mist sprayed from the spray 3 is constant, but when the amount of water vapor increases or decreases due to the breathing of the spray, the pressure in the powder production tower 2 fluctuates.

  When the internal pressure of the powder production tower 2 decreases, the pressures in the rectifying unit 17 and the negative pressure unit 16 also decrease. As a result, a larger amount of outside air is sucked from the outside air flow path 18, but since the flow resistance of the outside air flow path 18 is proportional to the square of the flow velocity, the pressure loss in the outside air flow path 18 greatly increases. For this reason, even if the internal pressure of the powder production tower 2 decreases, the amount of air supplied from the rectifying unit 17 does not increase so much, and the internal pressure of the powder production tower 2 is reduced.

  Conversely, when the internal pressure of the powder production tower 2 increases, the pressures in the rectifying unit 17 and the negative pressure unit 16 also increase. Then, the amount of outside air flowing from the outside air flow path 18 is reduced, and the pressure loss in the outside air flow path 18 is reduced. When the internal pressure of the powder generation tower 2 rises to a positive pressure with respect to the atmosphere, the pressure loss of the external air passage 18 disappears, and the air corresponding to the increase in the internal pressure of the powder production tower 2 flows from the external air passage 18 to the outside. It flows out and the internal pressure of the powder production tower 2 is reduced.

  In FIG. 3, the difference in the internal pressure fluctuation | variation of the powder production tower 2 with and without the outside air flow path 18 is shown. As shown in the figure, by providing the outside air flow path 18, the pressure fluctuation can be reduced only when the internal pressure of the powder production tower 2 is equal to or higher than the atmospheric pressure.

  The flame injection nozzle 7 does not misfire even if the internal pressure of the powder generation tower 2 decreases, but when the internal pressure increases, the fuel or combustion air injected from the flame injection nozzle 7 and the internal pressure of the powder generation tower 2 The pressure difference between the two causes a decrease in the flow rate of the fuel or combustion air, leading to a misfire of the flame injection nozzle, which may hinder manufacture. The outside air flow path 18 does not inhibit the internal pressure of the powder generation tower 2 from decreasing from the steady state, but can suppress the increase from the steady state (becomes positive pressure) and prevent the flame injection nozzle 7 from misfiring. .

FIG. 4 shows a powder production apparatus 1 ′ according to the second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
The powder production tower 2 ′ of the powder production apparatus 1 ′ does not have a double structure in which a metal container is kept warm as in the first embodiment, but is made of a heat insulating material 12 ′ made of a heat-resistant board or a castable refractory. The inner wall surface is a heat insulating board or the surface of a castable refractory 12 '. Further, the powder production apparatus 1 ′ does not have the air supply fan 4, and sucks outside air due to a pressure difference between the powder production tower 2 ′ and the atmosphere. As in the present embodiment, the outside air flow path 18 ′ may be a gap formed between the lid 19 that seals the opening 6 a of the sealing header 6 ′ and the sealing header 6 ′.

  Further, in the present invention, the powder production towers 2 and 2 'and the primary air flow path (carrier gas flow path) 5 are not distinguished by a mechanical structure, and the first embodiment of the present invention shown in FIG. Like the powder production apparatus 1 ″ of the third embodiment, the upper part of the structure forming the powder generation tower 2 ′ communicates with the rectifying unit 17 and is directed to the atmosphere of the part that guides air around the spray 3. Thus, the outside air flow path 20 may be provided in a portion that becomes negative pressure.

  In the present invention, the carrier gas fed into the powder generation towers 2 and 2 ′ by the air feed fan 4 may be any gas other than air, such as a gas containing a large amount of nitrogen or oxygen. In addition, a gas other than air may be sucked from the outside air passages 18 and 20 by making the atmosphere outside the powder generation towers 2 and 2 ′ a gas other than air.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic of the powder manufacturing apparatus of 1st Embodiment of this invention. FIG. 2 is a detailed cross-sectional view of a sealing header of the powder production apparatus of FIG. The graph which shows the internal pressure fluctuation | variation of the powder manufacturing apparatus of FIG. Schematic of the powder manufacturing apparatus of 2nd Embodiment of this invention. Schematic of the powder manufacturing apparatus of 3rd Embodiment of this invention.

Explanation of symbols

1,1 ', 1 "powder production equipment 2,2' powder production tower 3 spray (spraying means)
4 Air supply fan 5 Primary air flow path (carrier gas flow path)
6 Sealing header 7 Flame injection nozzle 9 Exhaust passage 11 Exhaust fan (exhaust device)
14 Throttle valve (flow control means)
DESCRIPTION OF SYMBOLS 15 Distribution part 16 Negative pressure part 17 Rectification part 18, 20 Outside air flow path

Claims (2)

A sealed cylindrical powder production tower;
Spraying means for spraying the aqueous raw material solution into the powder generating tower;
A carrier gas flow path for supplying a carrier gas from around the spraying means to the inside of the powder generation tower;
A flame injection nozzle for injecting a flame into the powder generation tower;
An exhaust device for discharging the gas in the powder generation tower from the powder generation tower;
The powder production apparatus according to claim 1, wherein the carrier gas flow path is provided with an open air flow path that is open to the outside in a negative pressure portion that is negative with respect to the outside in a steady state.   2. The powder production apparatus according to claim 1, wherein the exhaust device includes a flow rate control unit that controls a flow rate of a gas discharged from the powder production tower.

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