JPS605873B2 - Fluidized roasting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluidized fluidized furnace, and is particularly suitable for use as a barrel kiln for alumina using aluminum hydroxide as a flame.

A conventionally used fluidized burning furnace a as shown in Fig. 1 has a granular material supply port e, an overflow type granular material outlet b, a combustion gas outlet c, a wind box d, and an air diffuser plate. g, and a fluidized bed f of the material to be melted is formed.

The heat source may be a burner installed within the fluidized bed or a free board at the top of the furnace.
However, such a fluidized flame furnace has the following drawbacks. First, since high-temperature powder is handled, it is not possible to completely seal the gas at the Tomiharu entrance e, and the high-temperature gas flows back, reducing the performance of the preheating equipment in the previous process. Second, even in a fluidized bed with good mixing performance, the powder at the supply port e takes a short path and heads toward the outlet b, resulting in variations in quality. Thirdly, in order to obtain a granulated combustible material by supplying powder, if the powder is supplied from the upper part of the fluidized bed f, for example, from the supply port e, the powder will scatter, so it is necessary to You have to use something special. The present invention solves the above-mentioned drawbacks of the conventional fluidized incineration furnace. That is, the supply port at the lower end of the chute for charging powder and granules is placed above the diffuser plate toward the bottom of the fluidized bed. A conduit for supplying a small amount of compressed air is inserted into the lower part of this chute, making it possible to properly supply high-temperature raw material to the fluidized bed using a small amount of compressed air. The embodiment will now be described with reference to FIG.

FIG. 2 is a longitudinal sectional view showing an embodiment of the present invention.

In FIG. 2, reference numeral 1 denotes a furnace body made of a steel plate, with refractory bricks 2 stacked on the inner surface, a wind box 3 at the bottom, and a diffuser plate 4 at the top. Reference numeral 5 denotes a fluidized bed, and reference numeral 6 designates a sloped part in which the lower part slopes diagonally downward, and the supply port at the lower end is placed above the diffuser plate 4 and faces toward the bottom of the fluidized bed 5. , a powder bagging chute 7 for supplying powder and granular material from a position higher than the upper surface level of the fluidized bed 5 to the bottom of the fluidized bed 5; A compressed air conduit is inserted into the inclined part, 8 is an overflow port, 9 is an exhaust gas induction port, and 1 is a burner.

In the fluidized furnace constructed as shown in Fig. 2,
A fluidized bed 5 of granular material is formed by an appropriate amount of air ejected from the air diffuser plate 4, and fuel is ejected into the fluidized bed 5 by the burner 10, and is combusted by the air that has passed through the air diffuser plate 4, forming the fluidized bed. Heats the powder inside.

On the other hand, the heated granular material is introduced into the chute 6, and the granular material is supplied to the bottom of the fluidized bed 6 by a small amount of compressed air supplied into the chute 6 from the compressed air conduit 7. The powder and granules thus burned are discharged from the overflow port 8, and the exhaust gas is discharged from the exhaust gas induction port 9. Now, to show one experimental example, fluidized bed internal pressure (powder supply section); plus 140
W proboscis Aq powder; 1350qo, 90 realumina powder chute refractory inner diameter; 2o Qiu Cape supply amount: alumina 30k9'min, compressed air 0.2/min compressed air conduit diameter; 25 side compressed air conduit dawn Holes: Number of nozzle holes IQ False hole diameter 2 side The fluidized bed internal pressure plus 140mhAq in the above experimental example is the pressure at the bottom of the fluidized bed 5, and this pressure is used to control the powder and granules stored in the furnace in a certain amount. This is a positive pressure that corresponds to the upward force generated as a reaction force in the air.

On the other hand, when the granular material introduced into the chute 6 is supplied from a high-place, low-pressure container, the pressure balance between the pressure at the bottom of the fluidized bed 5 and the pressure at the granular material introduction position of the chute 6 is 2
As shown in the figure, first, the upper surface level of the fluidized bed 5 reaches the level of the overflow port 8, and the powder and granular material in the chute 6 reaches the overflow port 8.
This is just like the principle of a water manometer using a U-shaped tube, but in the case of high-temperature powder and granule, even in a fluid state, the viscosity of the powder and granule Due to its cohesive and adhesive properties, it does not flow like a water manometer.
Therefore, compressed air is injected from the air hole of the compressed air conduit 7 to actively move the powder and granular material, that is, to make the inside of the inclined part of the chute 6 into an active fluid state, and to move the powder from both ends of the chute 6 like a flow of water. The granular material is supplied to the bottom of the fluidized bed 5 from the V supply port. Furthermore, since the fluidized bed 5 and the inclined portion of the chute 6 are in a fluid state, some air rises within the bed.

Note that the diffused air passing through the chute 6 is a characteristic quantity, for example,
With the dimensional ratio of the embodiment shown in FIG. 2 and the experimental example described above, the amount of air coming out of the chute 6 is 1'64≠0.0 of the total diffused air amount.
Since it is about 16, it is possible to supply the powder to the bottom of the fluidized bed 6 while performing almost perfect sealing.
Therefore, the present invention provides a brothel equipped with a diffuser plate for forming a fluidized bed, an overflow port for discharging burned powder and granules out of the furnace, and an exhaust gas induction port for discharging exhaust gas. In this case, the lower part is a sloped part that slopes diagonally downward, and the supply outlet at the lower end is placed above the diffuser plate and faces toward the bottom of the fluidized bed, so that it is at the upper surface level of the fluidized bed. A chute for charging powder and granules is provided to supply the powder and granules from a higher position to the bottom of the fluidized bed, and the sloping part of the chute is provided with a compressed air passage having several holes. Because it is equipped with a conduit, it is possible to combine the high-temperature co-heated raw material with the bottom of the fluidized bed using a small amount of compressed air, and the backflow in the chute is negligible, and the There is no short path inside the furnace, and it has the best effect as a flaming furnace for alumina firing equipment, which performs granulation and firing in a sokei furnace, and uses the scarlet heat of this furnace to preheat the powder raw material. It is something that can be demonstrated.

In other words, when granulating in a furnace, it is necessary to supply raw materials to the bottom of the fluidized bed, so there are no restrictions due to powder temperature as with conventional feed pump or pneumatic feed methods. There is also little heat loss due to pressurized air. As described above, the present invention has a simple structure, low heat loss, and can reliably supply powder and granular material.
It is extremely large.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a subordinate column, and FIG. 2 is a longitudinal sectional front view of an embodiment of the present invention. 1...Furnace body, 2...Refractory bricks, 3...Wind box, 4
...Several air plates, 5...Fluidized bed, 6...
- Chute, 7... Compressed air conduit, 8... Overflow port, 9... Exhaust gas induction port, 10... Burner. Figure 1 Figure 2

Claims (1)

[Claims] 1. In a roasting furnace equipped with a diffuser plate for forming a fluidized bed, an overflow port for discharging roasted powder and granules out of the furnace, and an exhaust gas induction port for discharging exhaust gas, the lower part is slanted. The sloping part is slanted downward, and the supply port at the lower end is above the air diffuser plate, and is directed toward the bottom of the fluidized bed to collect powder and granules from a position higher than the upper surface level of the fluidized bed. A fluidized heating system comprising: a powder charging chute for supplying powder to the bottom of the fluidized bed; and a compressed air conduit having an appropriate number of injection holes in the inclined part of the chute. Furnace.