JPS5930614B2 - Diffusion method and device for powder in a transport pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for diffusing powder in a transport pipe.

A conventional powder transport device consists of a powder downcomer pipe for transportation and an ascending gas conduit (hereinafter referred to as the conduit).In this powder transport device, the powder descending from the powder downcomer pipe is The gas is fed into a conduit, and is transported upward by the rising airflow of gas flowing within this conduit.

However, in the case of this transportation device, the following (a) ~
The drawback of (c) occurs.

(a) When heat exchangeability with respect to powder is important in a raw material calcining furnace, etc., diffusion is insufficient.

(b) There is a large pressure loss due to gravity when the powder descends.

(c) If the volume of rising gas in the pipe is not constant,
It is not possible to transport the specified amount of powder.

Therefore, as shown in FIG. 1, a powder diffusion device has been proposed in which a diffusion plate 3 is attached to the lower part of the branch point between the powder downcomer pipe 1 and the conduit 2.

According to this powder dispersion device, the drawbacks (a) and (b) associated with the above-mentioned powder transport device that does not have a diffusion plate are improved to some extent, but on the contrary, the following (a) , (b)-2
Two disadvantages arise.

(a) Large particles of powder are deposited on the diffusion plate 3 as shown in FIG. 1A.

(b) The descending powder collides with the diffusion plate 3, and due to its repulsion, it hits a section of the wall of the conduit 2, and the powder adheres to that section and gradually accumulates, as shown in Figure 1B. Large clumps may form, leading to conduit blockages and other inconveniences.

The present inventors conducted extensive research to overcome the drawbacks associated with the above-mentioned conventional methods, and as a result, they collided the powder with a thin layer of air flow, that is, an air curtain, instead of a solid substance diffusion plate. It has been found that the diffusion is actively carried out, the powder is well dispersed, and the drawbacks of the above conventional methods are eliminated.

Furthermore, it has been found that even large particles of powder can be easily diffused by changing the air volume depending on the size of the powder particles.

Furthermore, in the case of a powder diffusion device equipped with a diffusion plate, the falling velocity of the powder is only temporarily reduced to zero, but when using an air curtain, pressure loss is not only completely eliminated, but also It has been found that the powder transport efficiency is improved because the air blown in is in substantially the same direction as the rising gas.

The present invention was completed based on these findings.

The present invention has the following features: (1) near a branch point between a powder downcomer pipe and a rising gas pipe that are connected to each other, high-speed air is blown into the rising gas pipe in substantially the same direction as the rising gas flow to form an air curtain; A method for diffusing powder in a transport pipe, characterized by diffusing the powder by colliding the air curtain with the descending powder; (2) a powder descending pipe and a rising gas conduit; An air blowing tube, such as a nozzle or similar device, is attached near the junction of the powder downcomer pipe and the rising gas conduit, which are connected to each other, and a high-velocity flow of air rises from the air blowing tube into the rising gas conduit. A powder diffusion device characterized by blowing in substantially the same direction as a gas flow to form an air curtain.
and (3) control that adjusts the volume of air blown from the air blowing pipe installed near the branch point of the powder downcomer pipe and the rising gas pipe by detecting the volume of the rising gas flowing in the rising gas pipe. The present invention relates to the powder diffusing device described in item (2) above, characterized in that it is equipped with a mechanism.

Hereinafter, the present invention will be explained in detail with reference to FIG.

Note that the same members as in FIG. 1 are given the same numbers.

The powder downcomer 1 and the ascending gas conduit 2 (also referred to as conduit 2) are connected to each other in the usual manner.

An air blowing pipe 4 such as a nozzle or similar device is added near the branching point between the powder downcomer pipe 1 and the conduit 2, and a high-speed air flows into the conduit 2 to cause an upward gas flow. It is set so that the air is blown in approximately the same direction as the air.

The air blowing pipe 4 is connected to an air compressor 5, and is set so that an air curtain C is formed inside the rising gas conduit 2.

By the way, in the present invention, the volume of air blown from the air blowing pipe 4 attached near the branch point between the powder downcomer pipe 1 and the conduit 2 is determined by detecting the volume of rising gas flowing into the conduit 2. A control mechanism may be provided to adjust the position.

Next, an example of the control mechanism and the operation of the powder diffusion device of the present invention will be described.

As the powder descends into the powder downcomer pipe 1, a high velocity air stream is blown through the air blowing pipe 4 and an ascending gas flows into the conduit 2.

Then, the flow rate of the rising gas in the conduit 2 is detected at a rising gas flow rate detection point m at a predetermined position of the conduit 2, and after inputting this detected amount to the converter 7, an output signal is input to the regulator 6.

At the same time, the amount of air blown from the air blowing pipe 4 is detected at a blowing amount detection point n at a predetermined position of the air blowing pipe 4, and this detected amount is input to the regulator 6.

Then, in order to set the ratio between the air flow rate and the rising gas flow rate to a predetermined value, the operating valve 8 is adjusted by the regulator 6, and the ratio between the air blowing volume and the rising gas flow rate is set to a predetermined value.

In this way, the amount of rising gas at eight points inside the conduit 2 can be set to a predetermined value, and the air curtain C can be reliably formed.

Therefore, the powder that has descended through the powder downcomer pipe 1 collides with the air curtain C, is diffused, and is transported by a predetermined amount by the rising gas rising inside the conduit 2.

As explained above, in the present invention, high-speed air is supplied from an air blowing pipe such as a nozzle or similar device installed near a branch point between a powder downcomer pipe and a rising gas conduit that are connected to each other. The rising gas is blown into the rising gas conduit in substantially the same direction as the flow of the rising gas to form an air curtain, and this air curtain is caused to collide with the descending powder.

Therefore, according to the present invention, since the powder is actively diffused by colliding with the air curtain, the powder can be reliably diffused.

Further, by changing the air volume depending on the size of the powder lump, it is possible to easily diffuse even large powder lumps.

Furthermore, in the case of a conventional powder diffusion device using a diffusion plate, the falling velocity of the powder is only temporarily reduced to zero, but in the case of the present invention, it is possible to completely eliminate pressure loss. Since the air blown in is in substantially the same direction as the rising direction of the rising gas, the powder transport efficiency is improved.

Incidentally, since large particles of powder pass through the air curtain C as shown in the second diagram, no accumulation of powder occurs near the branch point.

Furthermore, since the diffusion is well carried out, a phenomenon in which the powder adheres to the wall surface of the ascending gas conduit does not occur, and problems such as conduit blockage do not occur.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional powder diffusion device with a diffusion plate, and FIG. 2 is a schematic diagram of a powder diffusion device of the present invention. 1... Powder descending pipe, 2... Rising gas conduit, 4...
Air blowing pipe, 5...Air compressor, 6...Adjuster, 7...Converter, 8...Operation valve, m--rising gas flow rate detection point, n...Blowing rate detection point.

Claims (1)

[Claims] 1. A high-speed flow of air is blown into the rising gas pipe in substantially the same direction as the flow of the rising gas near the branch point between the powder downcomer pipe and the rising gas pipe that are connected to each other to form an air curtain. A method for diffusing powder in a transport pipe, characterized in that the powder is diffused by colliding the air curtain with the descending powder. 2 Connect the powder downcomer pipe and the rising gas conduit to each other, and install an air blowing pipe such as a nozzle or similar device near the branch point of the powder downcomer pipe and the rising gas pipe to inject high-speed air into the air. A powder diffusion device characterized by blowing from a blowing pipe into a rising gas conduit in substantially the same direction as the flow of rising gas to form an air curtain. 3. A control mechanism that adjusts the volume of air blown from the air blowing pipe installed near the junction of the powder downcomer pipe and the rising gas pipe by detecting the volume of the rising gas flowing in the rising gas pipe. A powder spreading device according to claim 2, characterized in that it comprises: