JPS6257394B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for removing dust from granules,
The purpose is to separate granules from finer dust attached to the granules.

Such particles include, in particular, alumina particles coming from systems for contacting polluted and dust gases from electrolyzers in the aluminum industry; This is done to fix it in the granules before they are released.
In practice, such alumina particles not only fix fluorine, but also fix fine contaminant dust such as carbon, iron, phosphorus, nickel, etc., but coarse particles of alumina are reused and used in the tank or the contact system. It is desirable to release and separate these dusts from the coarse particles of alumina to enable recirculation.

However, the present invention generally provides that, particularly when contaminating dust is a problem, it is desired that the coarse particles be reused and separated from the coarse particles if they have commercial value. Fine dust (mostly micron size)
This relates to all granular materials that have been adhered to.

It is an object of the present invention to provide a device which allows the separation between granules and fine dust to be carried out more efficiently than previously known devices and with very simple means.

The device of the present invention is a device for removing fine dust from granules and separating fine dust adhering to the granules, and the side surface of the device is connected to a permeable bottom wall and is connected to the bottom wall. a common separation chamber forming a fluidization zone and comprising a granule inlet tube and a granule outlet tube; a granule stream flowing from said granule inlet tube to a granule outlet tube across said fluidization zone; a plurality of transverse dividing walls installed in the common separation chamber and partitioning the common separation chamber into a plurality of chambers, each having at least one slit through which the particles in the fluidization zone can pass; a source of forced air in communication with the chamber; located in the fluidization region adjacent to the at least one slit and communicating with a source of compressed gas free of particles and at the same height as the slit through which the particles pass; The transverse jet stream of granules directed in opposite directions across the front face of the transverse dividing wall of the fluidization region and directed to the impingement zone within the granules flowing through said common separation chamber is directed at the height of the corresponding slit. and downstream thereof, opposing nozzles for generating air; and separation means for removing fine dust from the air blown up from the common separation chamber.

The method for removing dust from granules includes generating at least one jet of granules carrying fine dust, and moving this jet at a velocity sufficient to cause the fine dust to be released from the granules under the impact effect. A method is conceivable in which the fine dust is separated from the larger particles from which the dust has just been removed after hitting an obstacle.

The obstruction may consist of a fixed mesh against which the particles to be dusted are impinged, but it can also be particularly advantageous to provide at least one different jet of particles, in particular of the particles to be dusted. Consists of jet flow.

In other words, in that case it is essential to generate at least two jets facing each other consisting of the particles whose dust is to be removed, so that the particles of both jets collide and the particles are removed. The impact of the bodies and the intense turbulence cause the release of the fine dust adhering to it, which is then finally removed, for example by suction or blowing at low speeds, or by centrifuges or similar means. It consists of being separated from the granules.

Furthermore, one or more jets of granules may be formed by a stream of compressed air into which the granules are injected, or these jets may
The dust may also be generated by a stream of compressed air injected into a fluidized bed of granules to be removed.
This latter method has the advantage over the former method of avoiding rapid wear on the inside of the blowing nozzle.

The device of the present invention uses the latter method, and according to this device, the device is further divided into small partitions formed by horizontal dividing walls provided with slits through which the particles pass. This method is characterized in that the removal of dust from the granules is carried out in several stages in a fluidized bed flowing through a heated tank.

In an industrial embodiment, the problem is that it is continuous and particularly adapted to the treatment of relatively high flow rates of granules from which dust is removed.

Furthermore, whatever the method of removing dust from granules using the device of the invention, it is provided that the separation of the fine dust and the larger granules from which the dust is removed is carried out by means of a low velocity upward air flow. , which transports fine dust upward while larger particles descend.

In the case of the device of the invention, where the jet stream directed in the relative direction of the granules to be dusted is generated by a stream of compressed air injected into a fluidized bed of granules, this low-velocity upward air stream is is automatically created by air supplied to the blow-off nozzle in the fluidized bed along with air.

Various ways of carrying out the invention will be described below with reference to the schematic diagrams of the accompanying drawings, but the invention is not limited to these specific examples.

Figure 1 shows a method in which two blow-off nozzles are installed in opposite directions, one nozzle supplies compressed air, and the other nozzle supplies granules from which dust is removed. The disadvantage is that the inside of the nozzle that supplies the particles to be removed wears out prematurely.

The apparatus schematically shown in FIG. 1, which implements this method with the disadvantage of premature wear, is also called a separation chamber or intravenous chamber, and has two nozzles 2 extending through its opposing walls. It has chambers 1 facing in the same direction. (Two or more concentrated injection nozzles may be provided).

Each nozzle 2 is supplied with compressed air on the one hand and, for example, in tube 3, and on the other hand with the granules to be dusted (in tube 4). The two jets of particles from the nozzle 2 thus meet in the central region 5, the particles in the two jets collide, and the collision between the particles releases the fine dust adhering to them. This fine dust is then carried upwards from chamber 1 by the slow upward flow created by the air exiting the nozzle, while the larger particles, having been dusted, fall to the bottom of the chamber (hopper 6).

From this hopper the granules are removed and discharged or reused or, if necessary, recycled to the nozzle 2 for complete dust removal.

As for the fine dust transported upwards, it can be separated from the entrained air by electric filters or similar means and then the purified air can be discharged into the atmosphere.

As is often the case, especially when the granules from which the dust is being removed are highly abrasive,
To protect the inside of the nozzle from rapid wear, it is possible to inject only compressed air into the fluidized bed 7 of the granules to be dedusted, according to the example used in the device according to the invention shown in FIG. By this, it is possible to generate a jet stream of particles concentrated at two single points. Compressed air is supplied and the air from two opposite nozzles 8 pointing in the same direction entrains the particles to be dedusted in the fluidized bed 7 and actually transports them to the intermediate impingement zone 9 .

The fine dust thus released is on the one hand by the air from the nozzle 8 and on the other hand by the permeable bottom wall 11.
The fluidized air supplied from the forced air source by the air inlet 10 below is transported upwardly from the chamber and towards the filter by a low velocity upward flow. Also, larger particles from which dust has been removed from most
It descends to the fluidized bed 7 at the bottom of the chamber 1, where it is again subjected to the dust removal operation by impact, or from there it is successively discharged.

FIG. 3 shows a variant of the embodiment of FIG. 2 in which the axes of each of the two nozzles are at an angle, according to which the nozzle 8' supplies compressed air and projects into the fluidized bed 7 of the chamber 1. The installed nozzles likewise produce mutually opposed jets of the particles to be dusted off, and in such a way that the impingement zone 9' is located slightly above the upper region of the fluidized bed 7. , these nozzles are arranged so that their axes form a certain angle. This embodiment promotes separation between granules and dust.

It should be noted that here again more than one jet stream may be concentrated in the impingement zone 9'. In this case, the nozzle 8' is arranged conically. Note that 10 is an air inlet that supplies air from a controlled air source.

Finally, FIG. 4 shows a preferred embodiment of the invention, which can be used for the continuous treatment on an industrial scale of particles to be dedusted, for example alumina particles loaded with fine impurities.

In this case, a slightly inclined common separation chamber 12 is used, which is connected on its side to a permeable bottom wall 13 and which together with this bottom wall 13 forms a fluidization zone, in which the particles to be dusted are moved by gravity. (Air under the wall 13 Inlet (forced air source) not shown).

In the upper part of this common separation chamber 12 (above the wall 13), a transverse dividing wall (spacer) 14 is provided, for example, three
They are individually mounted, each having a horizontal slit 15 through which the grains pass from one chamber thus partitioned to the next. Furthermore, in order to realize the general principle of the invention, each chamber has a compressed air blowing nozzle 16 extending through the two opposite side walls of each chamber, at the same height as the corresponding slit 15 and downstream thereof. The nozzles are connected to a distribution header such as 17 and communicate with a source of particle-free compressed gas (not shown). Thereby, the compressed gas from the compressed gas source injects a transverse jet across the common separation chamber 12 through the slit 15 into the impingement zone within the particles flowing within the common separation chamber 12, and the impingement effect of the jet Fine dust is removed from the granules. Finally, above the chamber area extends a separation or infusion chamber 18 similar to the chamber 1 described in the previous figure.

The method of operating this device is also essentially the same as the method of operating the device described above. That is, the fine dust released from the larger particles in each chamber due to the collision effect of the two jets is discharged to the upper part of the chamber 18 by the upward air flow generated therein, and is ejected to the upper part of the chamber 18, as described above, for example, at a low velocity. is removed by suction or blowing, or by a centrifuge or similar means, while the dedusted alumina particles move downstream on the permeable bottom wall 13 and into the particle delivery tube. Transported to a series of exits.

The method of the present invention provides excellent dust removal efficiency, at least 50% efficiency, and furthermore, it is important to note that the method of the present invention provides excellent dust removal efficiency, an efficiency of at least 50%; It was confirmed that separation could be achieved.

It is clear from the foregoing, and it should be understood, that the present invention is not limited to the mode of application or to the specifically contemplated embodiments. On the contrary, it includes all changes to it.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the method using opposing nozzles;
Figure 2 is a model diagram showing an example that can be used in the present invention;
The figure is a model diagram showing a modification of FIG. 2 in which the axes of the two nozzles of the device that can be used in the present invention are at a certain angle;
FIG. 4 is a schematic diagram showing an apparatus according to a preferred embodiment of the present invention, which is suitable for high-speed, industrial continuous processing of granules from which dust is to be removed. 1... Chamber, 2, 8, 8'... Nozzle, 3...
Pipe, 4...Particle supply port, 5...Central area, 6...Hopper, 7...Fluidized bed, 9,9'...Central collision area,
10... Air inlet, 11, 13... Permeable bottom wall, 12... Common separation chamber, 14... Transverse dividing wall,
15...Slit, 16...Compressed air blowing nozzle, 17...Distribution pipe stop, 18...Separation room or intravenous injection room.

Claims (1)

[Scope of Claims] 1. A device for removing fine dust from granules and separating fine dust attached to the granules, the side surface of which is connected to a permeable bottom wall so that the device flows together with the bottom wall. a common separation chamber forming a fluidization zone and having a granule inlet pipe and a granule outlet pipe; a granule flow across the granule flow from the granule inlet pipe to the granule outlet pipe to the fluidization region; a plurality of transverse dividing walls installed to partition the common separation chamber into a plurality of chambers, each having at least one slit through which the particles in the fluidization zone can pass; a source of forced air in communication with a source of compressed gas located in the fluidization region and adjacent to said at least one slit and which does not contain granules and at the same height as said slit through which said slits pass; A transverse jet stream of granules directed in opposite directions across the front face of the transverse dividing wall of the fluidization zone and directed to the impingement zone within the granules flowing through said common separation chamber is directed at the height of the corresponding slit. , and downstream thereof, opposed nozzles for generating; and separation means for removing fine dust from the air blown up from said common separation chamber.