JPH0215792B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inclined kiln for firing limestone, dolomite, magnesite and other similar raw materials.

The structure of this type of tilting furnace is as shown in FIGS. 1 and 2.

Raw ore transported by a belt conveyor or the like is stored in a furnace top hopper 1, and is charged into the upper part of a body 3 by a raw ore input device 2. In the preheating zone 13, the injected raw ore is preheated by the combustion gas rising from below and flows down to the upper firing zone 14.
It is partially fired by the combustion gas from the upper burner 4 and flows down to the lower firing zone 15, at which point the object to be fired (original stone) is turned over and fired.

The material to be fired further flows down to the parallel flow firing zone 16, where the combustion gas formed by the injector 6 and flowing parallel to the material to be fired is used for final firing. The fired product that has been fired is then transferred to cooling zone 1.
7, and flows down while being cooled by the cooling air flowing in from the discharge part. The cooled fired product is discharged out of the furnace by a piston extrusion type discharge device 8.

A part of the combustion gas is transferred to the upper firing zone 14 and the preheating zone 1.
The air is taken out from the middle part of the air pump 3 and used by the recuperator 7 to preheat the air for operating the injector. In addition, the remaining combustion gas is used for preheating the fired product. These combustion gases are combined and sucked by an exhaust gas fan 9, pass through a dust collector 12, collect dust, and are released into the atmosphere.

The preheated working air is sent to the recuperator 7 by the blower 10, where it exchanges heat with the exhaust gas and is used as heated injector working air. Further, the hot air taken out from the middle part of the cooling zone 17 by the combustion air fan 11 after cooling the object to be fired is used as combustion air for the upper and lower firing burners 4 and 5.

Incidentally, for combustion in each of the burners 4 and 5, a space formed by the angle of repose of the raw material is used as an upper combustion chamber 4a and a lower combustion chamber 5a.

In addition, the upper burner 4 burns at an air ratio of approximately 0.5,
Excess air from the lower burner 5 causes combustion in the upper combustion chamber 4a and the object to be fired.

The lower burner 5 is operated at an air ratio of about 1.8, combining air for cooling the object to be fired and air for operating the injector. In addition, a part of the combustion gas generated by the lower burner 5 is combined with the product cooling air as a cocurrent gas that flows in the same direction as the object to be fired formed by the injector 6, and then flows to the lower part together with the injector working air. A circulating flow is provided to the burner 5. The other combustion gas in the lower burner 5 is sucked by the exhaust gas fan 9 to form a gas flow countercurrent to the object to be fired, and rises, and together with the combustion gas in the upper burner 4, passes through the preheating zone 13 and the requiperator 7 to the furnace. Exhausted outside.

18 is a sloped wall of a furnace provided in the lower firing zone 15, and 19 is a sloped wall of a furnace provided in the cocurrent firing zone 16.

The inclined firing furnace having such a configuration has the characteristics described below, which adversely affects the quality of the product or causes problems such as adhesion of the materials to be fired to the inner wall of the furnace. As a result, production decreases, unavoidable furnace shutdowns, deterioration of thermal efficiency,
There has been a decline in quality and removal of deposits. The characteristics of the inclined firing furnace that have such an effect will be explained with reference to FIGS. 3A, B, and C.

The material to be fired 20 filled in the furnace is placed on the inclined wall 1 of the furnace.
8 and 19 portions form a free respiration angle surface 21. A schematic cross section thereof is shown in FIG. 3a.

When the fired product is continuously discharged by the piston extrusion type discharge device 8 provided at the lower part of the furnace, the flow of the fired product 20 on the inclined walls 18 and 19 is as shown in FIG. 3b. become. That is, the flow rate of the object 20 to be fired is slow on the furnace wall side, and fast on the central part. As a result, a funnel-shaped flowing part is formed from the lower part of the inclined walls 18 and 19 to the free angle of repose surface 21 of the upper part of the object to be fired 20, and the angle of repose 21a of the object to be fired 20 is increased.
becomes steeper little by little.

Furthermore, when the fired product is discharged, the angle of repose 21a collapses, filling the funnel-shaped flowing part, and the third
As shown in FIG. C, a large amount of the material to be fired flows down onto the inclined walls 18 and 19 at one time, forming a surface with a slightly raised angle of repose 21b. Then, the material to be fired 20 flows down in the furnace from the upper part to the lower part while repeating a pattern in which a funnel-shaped flowing part is created by discharging the material by the discharging device 8.

Therefore, the material to be fired 20 on the surfaces of the inclined walls 18 and 19, after flowing down to the inclined walls 18 and 19,
It remains at the angle of repose surface for a long time until the angle of repose collapses, and is overheated by the burners 4 and 5. On the other hand, the material to be fired 20 at the lower part of the inclined wall has a slow flow rate, and fine particles sink to the bottom. Thing 2
0 adheres to the bottom of the inclined wall and remains there.

The present invention is intended to eliminate these drawbacks, and includes a nozzle that explosively injects compressed air on the inclined wall so that the material to be fired flows down uniformly.

Next, the present invention will be explained with reference to an embodiment shown in the drawings.

In one embodiment shown in FIG. 4, 22 is an injection nozzle, 23 is a quick exhaust valve, 24 is a reserve tank, and 25 is a compressed air source. Injection nozzle 2
2. Attach the required number of rapid exhaust valves 23 and reserve tanks 24 as one set to the inclined walls 18 and 19. Inclined wall 18,1 of the injection nozzle 22
The attachment point to 9 is the free repose angle surface 2 of the object to be fired 20.
The position corresponds to the part where 1 is formed.

Compressed air supplied from the compressed air source 25 is temporarily stored in the reserve tank 24 and maintained at a constant pressure. At the same time as the rapid exhaust valve 23 opens, compressed air is rapidly discharged into the furnace through the injection nozzle 22 with a large diameter. Here, the compressed air is injected in an explosive manner, and the kinetic energy of the compressed air impacts the object to be fired 20, forcing the angle of repose to collapse. Moreover, if a plurality of attached devices are operated at the same time, this effect will be even greater.

If this device is operated when the state shown in FIG. 3b has progressed a little, the state shown in FIG. 3a will be restored. Injecting compressed air in the state shown in FIG. 3b is most effective because the angle of repose of the object to be fired 20 is most likely to collapse. If these operations can be repeated in a short time, the object to be fired 2 can be fired almost continuously.
A flow of 0 is obtained.

Furthermore, as the air expands, pressure increases to peel off the laminated layers, and at the same time, the deposits on the inclined walls 18 and 19 are cleaned, and the material to be fired at the bottom is pushed to the front, reducing the flow rate at the bottom. It has the effect of speeding up.

Note that, depending on the application, it is also possible to use a gas such as nitrogen or carbon dioxide instead of compressed air.

As is clear from the above explanation, in the present invention, the tilted firing furnace is provided with a nozzle for injecting compressed air, which eliminates the drawbacks caused by the use of the tilted wall and allows the materials to be fired to flow down uniformly. This made it possible to fire high-quality products.

[Brief explanation of drawings]

FIG. 1 is a front view of an inclined firing furnace for adopting the present invention, FIG. 2 is a vertical cross-sectional view taken along the line -- in FIG.
FIGS. 3a to 3c are explanatory diagrams illustrating the flow characteristics of the material to be fired in the inclined wall portion according to the present invention, and FIG. 4 is a longitudinal sectional view of a main part showing an embodiment of the present invention. 3...Body, 4,5...Burner, 13...Pre-heating zone, 14...Upper firing zone, 15...Lower firing zone,
16... Co-current firing zone, 17... Cooling zone, 18,1
9... Inclined wall, 20... Material to be fired, 21... Injection nozzle, 22... Rapid exhaust valve, 23... Reserve tank, 24... Compressed air source.

Claims (1)

[Claims] 1 Raw stones are introduced from the top of the vertically installed body, heat is supplied from the slanted spaces at the top and bottom,
1. A tilted firing furnace for firing, characterized in that a nozzle for injecting compressed air is attached to an inclined wall portion.