JP6816958B2 - Chlorine Bypass Extraction Dust Treatment Method and Treatment Equipment - Google Patents

Description

The present invention relates to a method and a treatment device for chlorine bypass extracted dust contained in combustion gas extracted from a kiln exhaust gas flow path from the kiln bottom of a cement kiln to the lowermost cyclone of a preheater.

In recent years, recycling of waste as a raw material for cement and as fuel has been promoted, and as the amount of waste treated increases, the amount of volatile components such as chlorine brought into the cement kiln has also increased. Therefore, not only the quality of cement but also the chlorine bypass equipment that removes chlorine content that causes problems such as blockage of the preheater in the cement production equipment is indispensable.

As shown in FIG. 3, this chlorine bypass facility includes a probe 3 for extracting a part G of combustion gas from a kiln exhaust gas flow path from the kiln end of the cement kiln 2 to the lowermost cyclone (not shown), and a probe. A cooling fan 4 that supplies cold air to the inside of 3 to rapidly cool the extracted gas G, a cyclone 5 as a classification device that separates coarse dust D1 contained in the extracted gas G1, and fine powder D2 discharged from the cyclone 5. A cooler 6 that cools the extracted gas G2 including the above, a cooling fan 7 that supplies cold air to the cooler 6, a bug filter 8 that collects fine powder D4 in the exhaust gas G3 of the cooler 6, and discharge from the cooler 6. A dust tank 9 for collecting the fine powder D3 and the fine powder D4 (chlorine bypass dust D5) discharged from the bag filter 8 and a fan 10 for returning the exhaust gas G4 from the bag filter 8 to the cement kiln system are provided (for example). , Patent Documents 1 and 2).

Since the crude powder D1 having a particle size of 5 to 7 μm or more separated by the cyclone 5 has a low chlorine concentration, it is returned to the cement kiln system, and the recovered chlorine bypass dust D5 having a high chlorine concentration is cement clinker in the cement crushing step. After crushing with water or removing chlorine by washing with water, it is used as a raw material for cement.

Japanese Unexamined Patent Publication No. 2000-354838 JP-A-2010-195660

Since the chlorine bypass facility 21 has a high chlorine concentration of about 20 to 30% in the chlorine bypass dust D5, the chlorine content can be efficiently removed from the cement manufacturing facility. However, when chlorine bypass dust D5 is added to the cement clinker, slight fluctuations in the amount added and fluctuations in the chlorine concentration cause large fluctuations in the chlorine concentration of the cement to which chlorine bypass dust D5 is added, resulting in large fluctuations in the setting time and compression. It may affect cement quality such as strength.

Therefore, the present invention has been made in view of the above-mentioned problems in the prior art, and when chlorine bypass bleed dust is added to the cement clinker, the chlorine concentration is stabilized without affecting the cement quality. The purpose is to remove chlorine from cement manufacturing equipment more efficiently.

As a result of diligent research, the present inventors have found that the coarse powder separated by the cyclone of the chlorine bypass facility has a lower chlorine concentration than the chlorine bypass dust, but the fluctuation range of the chlorine concentration is small. We have found that it is easy to adjust the chlorine concentration, and have come up with the present invention. That is, in the method for treating chlorine bypass extracted dust according to the present invention, a part of the combustion exhaust gas is extracted from the kiln exhaust gas flow path from the bottom of the cement kiln to the lowermost cyclone of the preheater, and the extracted gas is extracted. This is a method for treating chlorine bypass extracted dust, which separates coarse powder from the coarse powder and recovers the fine powder from the extracted gas after the coarse powder is separated, and is separated from a part of the fine powder separated from the extracted gas and the extracted gas. It is characterized in that coarse powder having a fluctuation range of chlorine concentration smaller than that of the fine powder is added to a cement clinker in a cement crushing step to reduce the fluctuation of chlorine concentration of cement .

According to the present invention, by adding a coarse powder having a fluctuation range of chlorine concentration smaller than that of chlorine bypass dust to a cement clinker together with a part of fine powder, it is possible to stably control the cement production equipment while avoiding deterioration of cement quality. Chlorine can be removed.

The coarse powder separated from the extracted gas can be classified according to the chlorine concentration, and the fine powder obtained by the classification can be added to the cement clinker in the cement crushing step. This makes it possible to treat dust having a high chlorine concentration among the coarse powders.

Further, the present invention is a chlorine bypass extraction dust treatment device, which is a probe for extracting air while cooling a part of combustion exhaust gas from a kiln exhaust gas flow path from the kiln bottom of a cement kiln to the lowermost cyclone of a preheater. , A classification device that separates the extracted gas from the probe into coarse powder, fine powder, and gas, a part of the fine powder classified by the classification device, and classification by the classification device, and the chlorine concentration fluctuates more than that of the fine powder. A coarse powder having a small width is provided with an addition device for adding the coarse powder to the cement clinker in the cement crushing step, and a part of the fine powder and the coarse powder are added to the cement clinker to reduce the fluctuation of the chlorine concentration of the cement. It is characterized by that. According to the present invention, by adding a coarse powder having a fluctuation range of chlorine concentration smaller than that of chlorine bypass dust to a cement clinker together with a part of fine powder, it is possible to stably control the cement production equipment while avoiding deterioration of cement quality. Chlorine can be removed.

As described above, according to the chlorine bypass extracted dust treatment method and treatment apparatus according to the present invention, when chlorine bypass extracted dust is added to the cement clinker, the addition amount can be easily optimized and the cement manufacturing equipment can be used. Chlorine can be stably removed from.

It is an overall block diagram which shows 1st Embodiment of the chlorine bypass bleeding dust processing apparatus which concerns on this invention. It is an overall block diagram which shows the 2nd Embodiment of the chlorine bypass bleeding dust processing apparatus which concerns on this invention. It is an overall block diagram which shows an example of the conventional chlorine bypass equipment.

Next, a mode for carrying out the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of a chlorine bypass bleeding dust treatment device according to the present invention, in which the treatment device 1 is a kiln exhaust gas from a kiln tail of a cement kiln 2 to a bottom cyclone (not shown). The probe 3 that extracts a part of the combustion gas G from the flow path, the cooling fan 4 that supplies cold air to the inside of the probe 3 to quench the extracted gas G, and the coarse powder D1 of the dust contained in the extracted gas G1 are separated. In the cyclone 5 as a classification device, the cooler 6 for cooling the extracted gas G2 containing the fine powder D2 discharged from the cyclone 5, the cooling fan 7 for supplying cold air to the cooler 6, and the exhaust gas G3 of the cooler 6. From the bug filter 8 that collects the fine powder D4, the dust tank 9 that collects the fine powder D3 discharged from the cooler 6 and the fine powder D4 (chlorine bypass dust D5) discharged from the bag filter 8, and the bug filter 8. A fan 10 or the like for returning the exhaust gas G4 to a cement kiln system or the like is provided.

The processing device 1 has the same components as the conventional chlorine bypass facility 21 shown in FIG. 3, but as will be described later, the destination of D1 discharged from the cyclone 5 and the dust tank 9 is a cement crushing step or cement. It differs from the conventional chlorine bypass equipment 21 in that it is a kiln type and the destination of the chlorine bypass dust D5 is a cement crushing process and a water washing process.

Next, a method for treating chlorine bypass bleed dust using the chlorine bypass bleed dust treatment device 1 having the above configuration will be described with reference to FIG.

A part of the combustion gas G is extracted from the kiln exhaust gas flow path from the kiln bottom of the cement kiln 2 to the lowermost cyclone while being cooled by the probe 3, and the extracted gas G is extracted at 600 to 700 ° C., which is the melting point of the chlorine compound. Quench to the following.

The extracted gas G1 is introduced into the cyclone 5 and separated into a coarse powder D1 having a particle size of 5 to 7 μm or more and an extracted gas G2 containing the fine powder D2 to recover the coarse powder D1 while collecting the extracted gas G2 in the cooler 6. Cool with. Next, the bag filter 8 collects dust from the exhaust gas G3 of the cooler 6, collects the fine powder D4 contained in the exhaust gas G3, and collects the fine powder D3 collected from the cooler 6 as chlorine bypass dust D5. On the other hand, the exhaust gas G4 of the bug filter 8 is returned to the cement kiln system by the exhaust fan 10.

The above operation is the same as that of the conventional chlorine bypass facility 21 shown in FIG. 3, but the following operation is a feature of the chlorine bypass extracted dust treatment method according to the present invention.

The coarse powder D1 separated by the cyclone 5 is added to the cement clinker in the cement crushing step via an addition device including a transporter and a feeder. The crude powder D1 has a chlorine concentration of about 2%, which is lower than that of the chlorine bypass dust D5, but the fluctuation range of the chlorine concentration is about 0.5%. Therefore, it is possible to easily optimize the amount of addition to the cement clinker in the cement crushing step, and it is possible to stably remove chlorine from the cement manufacturing equipment while avoiding deterioration of cement quality. ..

On the other hand, in consideration of fluctuations in the chlorine concentration of chlorine bypass dust D5, a part of chlorine bypass dust D5 is added to the cement clinker and reused as a cement raw material after washing with water and desalting to reduce the quality of cement. While avoiding this, it is possible to stably remove chlorine from the cement manufacturing facility and reduce the amount of chlorine bypass dust D5 that is washed and desalted with water.

Next, an example of the method for treating chlorine bypass bleed dust will be described with reference to Table 1.

Examples 1 to 3 in which 1% by mass, 2% by mass, and 3% by mass of crude powder D1 were added to ordinary Portland cement containing 0.3% of chlorine bypass dust, and chlorine in which crude powder D1 was not added. A mortar test was conducted on a comparative example of only ordinary Portland cement containing 0.3% of bypass dust, and the qualities were compared. The results are shown in Table 1.

As shown in Table 1, there is no significant difference between the numerical values of Examples 1 to 3 to which the crude powder D1 is added and the numerical values of the comparative examples, and it can be seen that the quality of the cement is not deteriorated by the addition of the crude powder.

FIG. 2 shows a second embodiment of the chlorine bypass bleeding dust treatment device according to the present invention, in which the treatment device 11 further includes a classifier 12 and dust tanks 13 and 14 in the treatment device 1 shown in FIG. It has a provided configuration. The same components as those of the processing device 1 shown in FIG. 1 are designated by the same reference numbers, and the description thereof will be omitted.

In the present embodiment, the coarse powder D1 separated by the cyclone 5 is further classified by the classifier 12 (classification point 10 to 20 μm), and the fine powder D6 and the coarse powder D7 obtained by this classification are used in the dust tanks 13 and 14. Temporarily store in each.

Then, the fine powder D6 stored in the dust tank 13 is added to the cement clinker in the cement crushing step. As a result, since the fine powder D6 has a higher chlorine concentration than the total amount of the coarse powder D1, chlorine bypass bleed dust can be effectively used while efficiently removing chlorine from the cement manufacturing equipment. Further, a part of the coarse powder D7 stored in the dust tank 14 may be added to the cement clinker in the cement crushing step, and the entire amount of the coarse powder D7 or the rest after being added to the cement clinker is returned to the cement kiln system. You may.

On the other hand, in consideration of fluctuations in the chlorine concentration of chlorine bypass dust D5, a part of chlorine bypass dust D5 is added to the cement clinker and reused as a cement raw material after washing with water and desalting to reduce the quality of cement. While avoiding this, it is possible to stably remove chlorine from the cement manufacturing facility and reduce the amount of chlorine bypass dust D5 that is washed and desalted with water.

1 Chlorine bypass bleeding dust treatment device 2 Cement kiln 3 Probe 4 Cooling fan 5 Cyclone 6 Cooler 7 Cooling fan 8 Bug filter 9 Dust tank 10 Fan 11 Chlorine bypass bleeding dust treatment device 12 Classifier 13, 14 Dust tank

Claims (3)

A part of the combustion exhaust gas is extracted from the kiln exhaust gas flow path from the kiln bottom of the cement kiln to the lowermost cyclone of the preheater while cooling, the coarse powder is separated from the extracted gas, and the extracted gas after the coarse powder separation is performed. It is a treatment method of chlorine bypass bleeding dust that collects fine powder from the kiln.
A part of the fine powder separated from the extracted gas and a coarse powder separated from the extracted gas and having a smaller fluctuation range of chlorine concentration than the fine powder are added to the cement clinker in the cement crushing step to adjust the chlorine concentration of the cement. A method for treating chlorine bypass bleed dust, which is characterized by reducing fluctuations . The coarse powder separated from the extracted gas is classified according to the chlorine concentration.
The method for treating chlorine bypass extracted dust according to claim 1, wherein the fine powder obtained by the classification is added to the cement clinker in the cement crushing step. A probe that draws air while cooling a part of the combustion exhaust gas from the kiln exhaust gas flow path from the kiln butt of the cement kiln to the bottom cyclone of the preheater.
A classifier that separates the extracted gas from the probe into coarse powder, fine powder, and gas.
A part of the fine powder classified by the classification device and a coarse powder classified by the classification device and having a smaller fluctuation range of chlorine concentration than the fine powder are provided with an addition device for adding to the cement clinker in the cement crushing step. , chlorine bypass bleed dust processing apparatus and a portion with the coarse powder, wherein reduced to Rukoto variations in chlorine concentration of cement by adding to the cement clinker of the fines.

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