JP2000146458A - Device and method for regulating chlorine concentration of bypass dust - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bypass dust chlorine concentration regulating device and its method in which the chlorine concentration of the bypass dust to be recovered from the kiln exhaust gas can be regulated in a bypass device and a bypass method of the kiln exhaust gas. SOLUTION: The dust contained in the exhaust gas extracted from a kiln 11 through a probe 13 is classified into a rough powder dust and a bypass dust, the rough powder dust is recovered from a lower end part of a cyclone 14 and introduced in a rough powder dust post-adding device 21, and the exhaust gas containing the bypass dust is discharged from the cyclone 14 and fed to a cooler 15. A part of the rough powder dust is added from the exhaust gas containing the bypass dust from the rough powder dust post-adding device 21, and the remaining part of the rough powder dust is returned to the kiln system again. Since a part of the rough powder dust low in chlorine concentration is mixed in the bypass dust high in chlorine concentration, the quantity of generation of the dust to be recovered by a dust collector 16 and the chlorine concentration can be regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for adjusting the chlorine concentration of bypass dust, and more particularly to an apparatus and a method for adjusting the chlorine concentration of bypass dust recovered from kiln exhaust gas in a kiln exhaust gas bypass apparatus and method. .

[0002]

2. Description of the Related Art Volatile components such as chlorine introduced from raw materials and fuels in cement production are used in kilns and
It is concentrated by circulating in the pre-heater system, and may hinder stable operation of the kiln. Therefore, in order to remove volatile components from the kiln preheater system, a method is known in which a part of the kiln tail gas in which the volatile components are concentrated at a high concentration is extracted to the outside of the system by a bypass. FIG. 3 shows such a kiln exhaust gas bypass device. A part of the kiln tail gas of the kiln 1 is extracted and cooled by the probe 2, but chlorine is unevenly distributed particularly on the fine powder side of the dust generated by cooling.
After separating the coarse dust and the bypass dust into the kiln system using the μm as a classification point, and cooling the exhaust gas containing the separated bypass dust with the cooler 4,
The dust collector 5 collects the bypass dust. The collected bypass dust having a high chlorine content is stored in the dust tank 6 and added to the cement grinding system or processed outside the system.

[0003] By the way, an example of the ratio between the amount of generated bypass dust and coarse dust and the chlorine content is shown in Table 1 below.

[0004]

[Table 1]

In Table 1, the values in parentheses of the generated amount ratio and the chlorine amount ratio represent the ratios of the coarse dust and the whole dust (bypass dust + coarse dust) when the bypass dust is 1, respectively. . As can be seen from Table 1, the amount of bypass dust generated is only 16% of the entire dust, but its chlorine content accounts for 67%. On the other hand, the amount of generated coarse dust occupies 84% of the whole dust, but its chlorine amount is only 33%. Therefore, the chlorine concentration of the bypass dust is as high as 15%, which is about 10 times that of the coarse dust and about 4 times the average concentration of the whole dust. Thus, by using a classifier,
Efficient chlorine removal has been made possible with a small generation amount and with high dust concentration.

[0006]

However, the chlorine concentration of the bypass dust separated from the coarse dust by the classifier 3 and recovered by the dust collector 5 may be as high as, for example, 30%. In this case, In addition, there is a problem that the handling of the bypass dust becomes difficult, for example, because the hygroscopicity of the bypass dust increases and the adhesiveness increases, so that the bypass dust cannot be easily transported.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to control the chlorine concentration of bypass dust recovered from kiln exhaust gas in a kiln exhaust gas bypass device and method. It is an object of the present invention to provide an apparatus and a method for adjusting a density.

[0008]

According to a first aspect of the present invention, there is provided an apparatus for adjusting chlorine concentration of bypass dust, wherein the dust contained in exhaust gas extracted from the kiln is converted into bypass dust and coarse dust in a bypass device for kiln exhaust gas. A classifier that classifies and collects coarse dust, and a post-coarse dust dust addition device that adds a part of the coarse dust collected by the classifier to the bypass dust and returns the remaining coarse dust to the kiln system It is provided with.

According to a second aspect of the present invention, there is provided a bypass dust control apparatus for a kiln exhaust gas.
A classifier that classifies dust contained in exhaust gas extracted from the kiln into bypass dust and coarse dust to collect coarse dust and returns the collected coarse dust to the kiln system; And a collection efficiency adjuster for adjusting the collection efficiency of the dust.

[0010] A third aspect of the present invention provides a method for adjusting the chlorine concentration of bypass dust, which comprises:
The dust contained in the exhaust gas extracted from the kiln is classified into bypass dust and coarse dust, the coarse dust is collected, and a part of the collected coarse dust is added to the bypass dust and the remaining coarse dust is added. Is returned to the kiln system.

According to a fourth aspect of the present invention, there is provided a method for adjusting a chlorine concentration of bypass dust, the method comprising the steps of:
The dust contained in the exhaust gas extracted from the kiln is classified into bypass dust and coarse dust by a classifier to collect coarse dust, and the collection efficiency of the coarse dust is adjusted by the classifier, and the collected coarse powder is collected. This is a method of returning dust to the kiln system. In this case, a part of the collected coarse dust can be added to the bypass dust, and the remaining coarse dust can be returned to the kiln system.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Embodiment 1 FIG. FIG. 1 shows a flow diagram of a kiln exhaust gas bypass device provided with a bypass dust chlorine concentration adjusting device according to Embodiment 1 of the present invention. The tip of a probe 13 for extracting a part of the exhaust gas is inserted into a preheater 12 connected to the kiln 11. A cyclone 14 as a classifier is connected to the probe 13, and a dust collector 16 is connected to the cyclone 14 via a cooler 15. The dust collector 16 has a suction fan 17 and a dust tank 1.
8 are connected to the probe 13 and the cooler 15, respectively. Further, a coarse dust post-addition device 21 is connected to the cyclone 14.

As the probe 13, for example, a probe having a double tube structure having an inner cylinder and an outer cylinder as disclosed in Japanese Patent Application No. 9-192825 filed by the present applicant can be used. Cooling air supplied from the cool air fan 19 is sent to the tip of the probe 13 through a cylindrical flow path formed between the inner cylinder and the outer cylinder, and the kiln 11
A part of the exhaust gas is mixed with the cooling air and is cooled and extracted through the inner cylinder.

The coarse dust post-addition unit 21 adds a part of the coarse dust collected in the cyclone 14 to the exhaust gas including the bypass dust discharged from the cyclone 14 and also removes the remaining coarse dust to the kiln. It will be returned to the system.

Next, the operation of this embodiment will be described. First, the kiln 11 is driven by driving the suction fan 17.
A part of the exhaust gas generated by the operation of
At this time, cooling air is supplied from the cool air fan 19 to the flow path between the inner cylinder and the outer cylinder, and the exhaust gas is mixed with the cooling air at the tip of the probe 13 and cooled. Later, enter cyclone 14. The dust contained in the exhaust gas is classified into bypass dust and coarse dust with the classification point of 5 to 10 μm by the cyclone 14, and the exhaust gas containing the bypass dust is discharged from the cyclone 14 and sent to the cooler 15, Powder dust is cyclone 1
4 and enters the post-coarse dust addition device 21. Part of the coarse dust entering the post-coarse dust addition device 21 is added from the post-coarse dust addition device 21 to exhaust gas containing bypass dust, and the rest is returned to the kiln system again.

Exhaust gas containing bypass dust discharged from the cyclone 14 enters the cooler 15 in a state where a part of the coarse dust is added from the coarse dust post-addition device 21.
Here, after the heat is exchanged by the cooling air from the cool air fan 20 and cooled, the cooling air enters the dust collector 16. In the dust collector 16, bypass dust and coarse dust contained in the exhaust gas are collected and stored in the dust tank 18.

The dust stored in the dust tank 18 is
Since a part of the coarse dust having a low chlorine concentration is mixed with the bypass dust having a high chlorine concentration classified by the cyclone 14, the coarse dust from the post-addition device 21 for the coarse dust in the exhaust gas containing the bypass dust is used. Adjust the amount of dust generation within 1 to 6 times and the chlorine concentration within 1 to 0.2 times compared to the conventional bypass dust shown in Table 1 according to the amount of powder dust added. Becomes possible. In the first embodiment, the cyclone 14 is used as a classifier, but the apparatus is not limited to the cyclone as long as it has the same classifying performance. In the first embodiment, the coarse dust dust is added between the cyclone 14 and the cooler 15 in the first embodiment. However, the coarse dust dust is added between the cooler 15 and the dust collector 16 or in the first embodiment. It may be added directly to the dust tank 18.

Embodiment 2 FIG. FIG. 2 shows the inside of a cyclone 22 used in the apparatus for adjusting the chlorine concentration of bypass dust according to the second embodiment of the present invention. This cyclone 22
The inside thereof is provided with three continuous variable guide vanes 23 each capable of independently adjusting the angle. The entire width W of the guide vanes 23 is set to about 0.3 times the body radius R of the cyclone 22, and the height of the guide vanes 23 is set to be substantially equal to the height of the inlet 22 a of the cyclone 22.

In general, in the inside of the cyclone, the airflow flowing from the inlet and the airflow circling in the fuselage merge to generate a contraction, thereby obtaining a high dust collection efficiency. Are known to increase pressure loss. As shown in FIG. 2, when the variable guide vanes 23 are provided adjacent to the inlet 22a, when the variable guide vanes 23 are fully opened as shown in FIG. 2, these guide vanes 23 function as rectifying plates. Does not affect the dust collection efficiency, but when each guide vane 23 is rotated in the direction of the arrow so as to be in the fully closed state, the body swirl airflow colliding with the guide vane 23 is obstructed, so that the The generation is reduced, the pressure loss is reduced, and the dust collection efficiency is reduced. That is, the dust collection efficiency of the cyclone 22 can be changed by adjusting the angle of the variable guide vane 23.

In the second embodiment, a cyclone 22 having a variable guide vane 23 as described above is used instead of the cyclone 14 in the kiln exhaust gas bypass device of the first embodiment shown in FIG. The post-coarse dust dust addition device 21 used in the first embodiment is not used.

A part of the exhaust gas generated by the operation of the kiln 11 by the operation of the suction fan 17 is bled from the inner cylinder of the probe 13. Cooling air is supplied to the flow path, and the exhaust gas is mixed with cooling air at the tip of the probe 13 and cooled, and then enters the cyclone 22. The dust contained in the exhaust gas is classified into bypass dust and coarse dust by the cyclone 22, and the coarse dust is recovered from the lower part of the cyclone 22, but by changing the angle of the variable guide vane 23 in the cyclone 22. And the dust collection efficiency of the cyclone 22, that is, the collection efficiency of the coarse dust can be adjusted.

The coarse dust collected by the cyclone 22 is returned to the kiln system again. On the other hand, the exhaust gas containing the bypass dust is discharged from the cyclone 22 and sent to the cooler 15, where it is cooled by heat exchange with the cooling air from the cool air fan 20 and then enters the dust collector 16. In the dust collector 16, bypass dust contained in the exhaust gas is collected and stored in a dust tank 18.

The dust stored in the dust tank 18 is
Although it contains bypass dust having a high chlorine concentration classified by the cyclone 22, a part of coarse powder dust having a low chlorine concentration can be mixed depending on the degree of opening and closing of the variable guide vane 23 in the cyclone 22, so that the variable guide is used. According to the angle adjustment of the vane 23, the amount of generated dust and the chlorine concentration can be adjusted. In the second embodiment, the cyclone 22 having the variable guide vanes 23 is used. However, the cyclone 22 is not limited to such a cyclone as long as the collection efficiency of the coarse dust can be adjusted.

A cyclone 22 having a variable guide vane 23 as shown in FIG. 2 is used in place of the cyclone 14 of the first embodiment shown in FIG. 1, and a post-coarse dust dust adding device 21 is added to the cyclone 22. It can also be used by connecting.

[0025]

As described above, according to the present invention, a part of the coarse dust collected and classified by the classifier is added to the bypass dust, and the remaining coarse dust is returned to the kiln system. Alternatively, since the collection efficiency of the coarse dust in the classifier is adjusted and the collected coarse dust is returned to the kiln system, it is possible to adjust the chlorine concentration and the generation amount of the bypass dust. When the chlorine concentration of the collected bypass dust is too high, when the adhesion of the dust increases and handling becomes difficult, the chlorine concentration of the bypass dust is adjusted by the apparatus and method for controlling the chlorine concentration of the bypass dust according to the present invention. By lowering, the adhesion of dust can be reduced and the problem can be avoided. In addition, when there is a sufficient amount of bypass dust treatment, for example, in a method of adding bypass dust to a cement grinding system, when there is a sufficient amount of bypass dust addition within a range that does not adversely affect the quality of the cement, or For example, in the method of using bypass dust as a cement raw material after washing and desalination, if there is a sufficient amount of processing capacity of the washing and desalination equipment, dare to collect a small amount of bypass dust having a high chlorine concentration. Since it is unnecessary to collect the bypass dust and the coarse dust in a mixed state, the apparatus and method for adjusting the chlorine concentration of bypass dust according to the present invention are particularly effective.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a kiln exhaust gas bypass device including a bypass dust chlorine concentration adjusting device according to Embodiment 1 of the present invention.

FIG. 2 is a schematic plan view showing the inside of a cyclone used in a second embodiment.

FIG. 3 is a flowchart showing a conventional kiln exhaust gas bypass device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Kiln 12 Preheater 13 Probe 14 and 22 Cyclone 15 Cooler 16 Dust collector 17 Suction fan 18 Dust tank 19 and 20 Cold air fan 21 Coarse dust dust addition device 23 Variable guide vane

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D002 AA18 AC05 BA13 BA14 CA13 CA20 DA66 DA70 GA01 GA02 GB02 GB03 GB06 GB08 GB12 4D053 AA03 AB01 BA01 BB02 BC01 BD04 CA20 CB14 CC10 CC11 CF01 CG09 DA04 4K056 AA12 BA06 CA08 DB07 DB13 DB23

Claims (5)

[Claims] 1. A bypass device for kiln exhaust gas, comprising: a classifier for classifying dust contained in exhaust gas extracted from the kiln into bypass dust and coarse dust to collect coarse dust; A post-coarse dust dust addition device for adding a portion of the coarse dust to the bypass dust and returning the remaining coarse dust to the kiln system. 2. A bypass device for kiln exhaust gas, wherein dust contained in exhaust gas extracted from the kiln is classified into bypass dust and coarse dust, coarse dust is collected, and the collected coarse dust is collected in a kiln system. An apparatus for adjusting the chlorine concentration of bypass dust, comprising: a classifier for returning to the inside; and a collection efficiency adjuster for adjusting the collection efficiency of coarse dust in the classifier. 3. A method for bypassing kiln exhaust gas, wherein dust contained in exhaust gas extracted from the kiln is classified into bypass dust and coarse dust, coarse dust is collected, and part of the collected coarse dust is collected. Adding chlorine to the bypass dust and returning the remaining coarse powder dust into the kiln system. 4. A method for bypassing kiln exhaust gas, wherein the dust contained in the exhaust gas extracted from the kiln is classified into bypass dust and coarse dust by a classifier to collect the coarse dust, and the coarse dust is collected by the classifier. A method for adjusting the chlorine concentration of bypass dust, comprising adjusting the collection efficiency of the waste dust and returning the collected coarse dust to the kiln system. 5. The method of claim 4, wherein a part of the collected coarse dust is added to the bypass dust and the remaining coarse dust is returned to the kiln system. .