JPS6024412Y2 - Preheating and firing equipment for powder and granular materials - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a preheating and firing device for granular materials such as limestone and dolomite.

In the firing furnace, there are differences depending on the characteristics, but 1. In order to continue operation while maintaining good quality, fuel consumption, and electricity consumption, it is necessary to narrow the particle size distribution of the raw material to be processed.

If the particle size distribution is wide, (1) Burning becomes more uneven.

(2) In order to prevent uneven burning, the fuel consumption rate tends to increase.

(3) In connection with these, sticking, dust troubles, etc. are likely to occur.

There are problems such as.

In order to deal with these problems, the applicant first
As shown in JP-A No. 55-22307, instead of using pre-classified raw materials, the raw materials are charged and classified into multiple stages while being preheated, and each of the classified raw materials is heated in a separate firing device. We have developed and proposed a preheating and sintering device for powder and granular materials that can be fired and efficiently sintered, eliminating the above-mentioned drawbacks, even when raw materials have a wide particle size distribution.

The specific configuration of this device was as follows.

That is, the raw material preheated by the preheating device can be supplied to the coarse particle classification cyclone and the fine particle classification cyclone, and the preheating gas can be supplied to the preheating device through the coarse particle classification cyclone and the fine particle classification cyclone. like,
It is equipped with a raw material preheating device, a cyclone for coarse grain classification, and a cyclone for fine grain classification, and is connected to a cyclone for coarse grain classification in a rotary kiln for firing the coarse grain raw material classified by this cyclone for coarse grain classification. A rotary kiln for fine-grain firing of the fine-grain raw materials classified by the fine-grain classification cyclone is directly connected to the fine-grain classification cyclone, and the exhaust gas of the coarse-grain firing rotary kiln is used for the coarse-grain classification. It was configured to be supplied to a cyclone and the above-mentioned fine particle classification cyclone for airflow classification.

However, even with this type of preheating and sintering equipment for powder and granular materials, rotary kilns are used as the sintering equipment for both coarse and fine grains, so the heat dissipation area is large, so heat dissipation is difficult. The fuel consumption is large, requires a large amount of heat, and has poor thermal efficiency, which remains an obstacle to further lowering the fuel consumption rate of the entire device.

Furthermore, rotary kilns are large and require a large installation area, which also poses the problem of high costs for equipment.

The present invention was made to improve these problems, and instead of using the rotary kiln for firing fine grains among the conventional rotary kilns for coarse grains and fine grains, This is done in a classification cyclone.

That is, in the present invention, fine grains are fired by airflow firing, which has good thermal efficiency and high firing efficiency, in a cyclone for classifying fine grains, and coarse grains have a large surface area, so they are fired sufficiently to have a firing effect. Since residence time is required, we decided to fire it in a rotary kiln as usual.

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

In FIG. 1, 5 is a first preheating device for preheating raw materials; 6
7 is the second cyclone for coarse grain classification that also serves as the second preheating
8 is a rotary kiln for firing coarse grains connected to the cyclone 6 for classifying coarse grains, and the raw material M is transferred as shown by the solid arrow, and the exhaust gas G flows as shown by the dotted arrow.

The raw material M preheated by the preheating device 5 is supplied to the preheating coarse particle classification cyclone 6 and the fine particle classification cyclone 7, and the preheating hot gas G is supplied to the preheating coarse particle classification cyclone 6 and the fine particle classification cyclone 7. A preheating device 5 for the raw material M, a cyclone 6 for preheating coarse particle classification, and a cyclone 7 for fine particle classification and firing are arranged so that the raw material M can be supplied to the preheating device 5 through the cyclone 7. A rotary kiln 8 for coarse-grain firing of the classified coarse-grained raw material is connected to a preheated coarse-grain classification cyclone 6, and the fine-grained raw material is classified and fired at the same time by the cyclone 7 for fine-grain classification and firing. The exhaust gas from the rotary kiln 8 for firing coarse grains was supplied to a preheated cyclone 6 for classifying coarse grains and a cyclone 7 for classifying fine grains and firing, so that it could be classified by air stream.

To further explain the embodiment of the present invention, a one-stage cyclone is used as the preheating coarse particle classification cyclone 6, and a one-stage cyclone is also applied to the fine particle classification and firing cyclone 7. It was equipped with a burner 7' for use in a firing cyclone system.

In this case, the raw material is classified by a two-stage cyclone,
The coarse grains are separated by the preheated coarse grain classification cyclone 6 in the second stage, and the remaining fine grains are sent to the second stage fine grain classification and firing cyclone 7, where they are separated and fired.

In addition, when the particle size range of the raw material is wide, the cyclone 6 for preheating coarse grain classification may be provided in two or more stages, and the rotary kiln 8 for coarse grain firing may be provided in two or more stages. Two or more 7s may be provided.

In this case, if the number of coarse grain classification stages is increased unnecessarily,
A large number of rotary kilns for coarse-grain firing are required, which increases heat dissipation unnecessarily, which is not a good idea, and it is necessary to determine the minimum number of classification stages necessary within the range that can minimize uneven burning caused by rotary kilns. .

1o is a kiln exhaust gas duct connected between the rotary kiln 8 for coarse grain firing and the cyclone 6 for coarse grain classification, and supplies the exhaust gas of the rotary kiln 8 to the cyclone 6;
1 is a raw material input device that supplies the raw material M preheated by the preheating device 5 into the kiln exhaust gas duct 1o through the pipe 9;
12 is a duct connecting the gas outlet of the cyclone 6 for coarse particle classification and the gas inlet of the cyclone 7 for fine particle classification and firing;
A duct 14 connects the gas outlet of the cyclone 7 for fine particle classification and firing and the gas inlet of the preheating device 5, and a duct 14 connects the gas outlet of the cyclone 7 for fine particle classification and firing to the gas inlet of the preheating device 5. The coarse particle input chute 13 that supplies the rotary kiln 8 is an air lock feeder that discharges the fine particles fired in the cyclone 7 for classifying and firing fine particles.

The operation of this embodiment with such a configuration will be explained as follows.
The raw material M input into the preheating device 5 descends while being preheated, is discharged into the pipe 9, is input into the duct 10 by the raw material input device 11 installed in the horizontal part of the kiln exhaust gas duct 10, and is discharged into the duct 10. It is conveyed by duct G and enters cyclone 6 for coarse particle classification while being preheated.

Here, coarse particles with a particle size of 1 wrL or more are separated, and fine particles with a particle size of 1 rfrIn or less are further preheated and passed through a duct 12 into a cyclone 7 for fine particle classification and firing.
Separated and fired.

coarse grain raw material M2 classified by the cyclone 6 for coarse grain classification;
After passing through the airlock feeder 13, coarse grains are introduced into the chute 1.
4, the coarse grain raw material Mb is fed into a rotary kiln 8 for firing coarse grains, and here, the coarse grain raw material Mb is fired while maintaining a necessary residence time to obtain a sufficient firing effect.

Then, the fired products are sequentially discharged from the rear of the rotary kiln 8 for firing coarse grains and transferred to a cooler (not shown).

Further, the fine grain raw material Mb separated by the fine grain classification and firing cyclone 7 is fired inside the cyclone 7 by a firing burner 7' provided in the cyclone 7.

In this case, since the fine grain raw material is subjected to air flow firing inside the fine grain classification and firing cyclone 7, the firing efficiency is good, and since the thermal efficiency is good, there is little heat dissipation.

The baked products are sequentially discharged through the air lock feeder 15 and transferred to a cooler (not shown).

On the other hand, the kiln exhaust gas G passes through the kiln exhaust gas duct 10, further preheats the raw material supplied into this duct 10 by the raw material input device 11, and is conveyed, reaches the preheated coarse particle classification cyclone 6, and further passes through the duct. 12, it reaches the cyclone 7 for fine grain classification and firing, where most of the fine grain raw material Mb
After separating the Mb fired product, it is passed through the preheating hot gas duct 16 together with the combustion exhaust gas from the firing burner 7'.
The raw material M is then introduced into the preheating device 5, rises while preheating the raw material M, and is discharged from the preheating device 5 to the outside.

In this way, the present invention preheats the raw materials and classifies them into multiple stages, and then fires the classified raw materials in separate firing devices, so even raw materials with a wide particle size distribution can be baked evenly and uniformly. The firing of fine-grained raw materials has poor firing efficiency, and the heat dissipation area is large.
(7) Instead of using a tari kiln, air current firing is performed inside the fine grain classification cyclone, which has good heat conduction to the raw material and has good firing efficiency, so it is different from the conventional method of firing fine grain raw materials in a rotary kiln. Compared to other systems, heat dissipation can be further suppressed and fuel consumption can be further reduced.

In this case, the cyclone has a small heat dissipation area and can be easily kept warm, so it is more effective in reducing heat dissipation.

Furthermore, by eliminating the rotary kiln for firing fine grains, which is a larger piece of equipment than conventional equipment, the installation area of the equipment can be reduced accordingly, power consumption can be reduced, and equipment costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a front view showing one embodiment of the present invention. 5... Preheating device, 6... cyclone for preheating coarse particle classification, 7... cyclone for fine particle classification and firing, 7'... burner for baking, 8... Rotary kiln for coarse grain firing, 10, 12, 16...
・Duct, 11... Raw material input device, 14...
...Coarse grain input chute, Ma... Coarse grain raw material,
Mb...Fine raw material, G...Exhaust gas, M.
·····material.

Claims (1)

[Scope of utility model registration request] The raw material preheated by the preheating device is supplied to the cyclone for coarse particle classification and the cyclone for fine particle classification, and the hot gas for preheating is supplied to the preheating device through the cyclone for coarse particle classification and the cyclone for fine particle classification. A raw material preheating device, a cyclone for coarse particle classification, and a cyclone for fine particle classification are arranged in the cyclone, and a rotary kiln for firing the coarse raw material classified by the cyclone for coarse particle classification is connected to the cyclone for coarse particle classification. In the apparatus for preheating and sintering powder and granular materials, the apparatus is configured to supply exhaust gas from the rotary kiln for calcination of coarse particles to the cyclone for classifying coarse particles and the cyclone for classifying fine particles for air flow classification. A preheating and firing device for powder and granular materials, characterized in that a cyclone for grain classification is equipped with a burner for firing fine grain raw materials.