JP2017145166A - Treatment method and treatment device of chlorine bypass extraction steam dust - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stably removing a chlorine component from a cement manufacturing facility while avoiding reduction of cement quality when a chlorine bypass extraction steam dust is added to cement clinker.SOLUTION: There is provided a treatment method of a chlorine bypass extraction steam dust by extracting a part of flue gas G from a kiln exhaust gas from a kiln tail of a cement kiln 2 to a lowermost cyclone of a pre-heater while cooling the same, separating a coarse powder D1 from the extracted gas and recovering fine powder from the extracted gas after separation of the coarse powder, including adding a part of fine powder D2 separated from the extracted gas G2 and the coarse powder separated from the extracted gas to a cement clinker in a cement pulverization process. There is provided a method for classifying the coarse powder separated from the extracted gas and adding a fine powder D6 obtained by the classification to the cement clinker in the cement pulverization process.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method and an apparatus for treating chlorine bypass bleed dust contained in combustion gas extracted from a kiln exhaust gas passage from a kiln bottom of a cement kiln to a lowermost cyclone of a preheater.

  In recent years, recycling of wastes as cement raw materials and fuels has been promoted, and the amount of volatile components such as chlorine components brought into the cement kiln is increasing with the increase in the amount of waste processing. Therefore, not only the quality of cement, but also a chlorine bypass facility that removes chlorine that causes problems such as blockage of preheaters in cement manufacturing facilities is indispensable.

  As shown in FIG. 3, the chlorine bypass facility includes a probe 3 for extracting a part of combustion gas G from a kiln exhaust gas flow path from the bottom of the cement kiln 2 to the lowermost cyclone (not shown), and a probe 3, a cooling fan 4 for rapidly cooling the extraction gas G by supplying cold air, a cyclone 5 as a classification device for separating the coarse dust D1 contained in the extraction gas G1, and a fine powder D2 discharged from the cyclone 5 A cooler 6 that cools the bleed gas G2 containing air, a cooling fan 7 that supplies cool air to the cooler 6, a bag filter 8 that collects the fine powder D4 in the exhaust gas G3 of the cooler 6, and an exhaust from the cooler 6 The 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 the exhaust gas G4 from the bag filter 8 are returned to the cement kiln system. It comprises Because of the fan 10 and the like (e.g., Patent Documents 1 and 2).

  Since the coarse powder D1 having a particle diameter 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 grinding process. It is used as a cement raw material etc. after pulverizing with or removing chlorine by washing with water.

JP 2000-354838 A JP 2010-195660 A

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

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

  As a result of intensive research, the present inventors have found that the coarse powder separated by the cyclone of the chlorine bypass facility has a low chlorine concentration compared to the chlorine bypass dust, but the fluctuation range of the chlorine concentration is small. The inventors have found that the chlorine concentration can be easily adjusted and have reached the present invention. That is, the chlorine bypass bleed dust processing method according to the present invention bleeds while cooling a part of the combustion exhaust gas from the kiln exhaust gas flow path from the bottom of the cement kiln to the lowermost cyclone of the preheater, A method of treating chlorine bypass bleed dust that separates coarse powder from the pulverized gas and collects fine powder from the bleed gas after separation of the coarse powder, wherein a part of the fine powder separated from the bleed gas is separated from the bleed gas. The coarse powder is added to the cement clinker in the cement grinding step.

  According to the present invention, a coarse powder having a smaller fluctuation range of the chlorine concentration than the chlorine bypass dust is added to the cement clinker together with a part of the fine powder, so that deterioration of cement quality can be avoided and stable from the cement production facility. Chlorine can be removed.

  The coarse powder separated from the extraction 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 grinding step. Thereby, dust with a high chlorine concentration can be treated among the coarse powders.

  In addition, the present invention is a chlorine bypass bleed dust processing apparatus, and a probe that bleeds while cooling a part of the combustion exhaust gas from the kiln exhaust gas flow path from the bottom of the cement kiln to the bottom cyclone of the preheater, A cement pulverizing step for classifying the separation gas extracted by the probe into coarse powder, fine powder and gas, a part of the fine powder classified by the classifier, and the coarse powder classified by the classifier And an addition device for adding to the cement clinker. According to the present invention, a coarse powder having a smaller fluctuation range of the chlorine concentration than the chlorine bypass dust is added to the cement clinker together with a part of the fine powder, so that deterioration in cement quality can be avoided and stable from the cement production facility. Chlorine can be removed.

  As described above, according to the method and apparatus for processing chlorine bypass bleed dust according to the present invention, when adding chlorine bypass bleed dust to a cement clinker, the amount of addition can be easily optimized, and cement manufacturing equipment Chlorine can be stably removed from

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows 1st Embodiment of the processing apparatus of the chlorine bypass bleed dust which concerns on this invention. It is a whole block diagram which shows 2nd Embodiment of the processing apparatus of the chlorine bypass bleed dust which concerns on this invention. It is a whole block diagram which shows an example of the conventional chlorine bypass installation.

  Next, an embodiment 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 bleed dust processing apparatus according to the present invention. This processing apparatus 1 is a kiln exhaust gas from the bottom of a cement kiln 2 to a lowermost cyclone (not shown). The probe 3 for extracting a part of the combustion gas G from the flow path, the cooling fan 4 for rapidly cooling the extraction gas G by supplying cold air to the inside of the probe 3, and the coarse dust D1 of the dust contained in the extraction gas G1 are separated. A cyclone 5 as a classifying device, a cooler 6 that cools an extraction gas G2 containing fine powder D2 discharged from the cyclone 5, a cooling fan 7 that supplies cool air to the cooler 6, and an exhaust gas G3 of the cooler 6 Filter 8 for collecting the fine powder D4, dust tank 9 for collecting the fine powder D3 discharged from the cooler 6 and fine powder D4 (chlorine bypass dust D5) discharged from the bag filter 8, The exhaust gas G4 from the filter 8 comprising a like fan 10 for returning the cement kiln system, and the like.

  Although the said processing apparatus 1 consists of the component similar to the conventional chlorine bypass equipment 21 shown in FIG. 3, as mentioned later, the transport destination of D1 discharged | emitted from the cyclone 5 and the dust tank 9 is used as a cement grinding | pulverization process or a cement. It differs from the conventional chlorine bypass facility 21 in that it is a kiln system and the transport destination of the chlorine bypass dust D5 is a cement grinding process and a water washing process.

  Next, a chlorine bypass bleed dust processing method using the chlorine bypass bleed dust processing apparatus 1 having the above-described configuration will be described with reference to FIG.

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

  The extraction gas G1 is introduced into the cyclone 5 and separated into a coarse powder D1 having a particle diameter of 5 to 7 μm or more and an extraction gas G2 containing the fine powder D2, and the coarse powder D1 is recovered while the extraction gas G2 is cooled 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 it together with the fine powder D3 recovered from the cooler 6 as chlorine bypass dust D5. On the other hand, the exhaust gas G4 from the bag 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 bleed dust processing method according to the present invention.

  The coarse powder D1 separated by the cyclone 5 is added to the cement clinker in the cement pulverization process via an adding device including a transporter and a feeder. The coarse powder D1 has a chlorine concentration of about 2% and is lower than 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 addition amount when added to the cement clinker in the cement crushing process, and to stably remove chlorine from the cement manufacturing facility while avoiding deterioration of the cement quality. .

  On the other hand, considering the fluctuation of chlorine concentration in the chlorine bypass dust D5, a part of the chlorine bypass dust D5 is added to the cement clinker and reused as a cement raw material after washing and desalting, thereby reducing the cement quality. While avoiding, the chlorine content can be stably removed from the cement production facility, and the amount of chlorine bypass dust D5 to be washed and desalted can be reduced.

  Next, an embodiment of the chlorine bypass bleed dust processing method 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 coarse powder D1 were added to ordinary Portland cement containing 0.3% of chlorine bypass dust, and no coarse powder D1 was added. A mortar test was performed on a comparative example of only ordinary Portland cement containing 0.3% of bypass dust, and the quality was compared. The results are shown in Table 1.

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

  FIG. 2 shows a second embodiment of the chlorine bypass bleed dust processing apparatus according to the present invention. This processing apparatus 11 further includes a classifier 12 and dust tanks 13 and 14 in the processing apparatus 1 shown in FIG. It has a configuration provided. The same constituent elements as those of the processing apparatus 1 shown in FIG.

  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 stored in the dust tanks 13 and 14. Store temporarily in each.

  Then, the fine powder D6 stored in the dust tank 13 is added to the cement clinker in the cement grinding process. Thereby, since this fine powder D6 has a high chlorine concentration compared to the total amount of the coarse powder D1, it is possible to effectively use the chlorine bypass bleed dust while efficiently removing chlorine from the cement manufacturing facility. 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 process, and the entire amount of the coarse powder D7 or the remainder after addition to the cement clinker is returned to the cement kiln system. May be.

  On the other hand, considering the fluctuation of chlorine concentration in the chlorine bypass dust D5, a part of the chlorine bypass dust D5 is added to the cement clinker and reused as a cement raw material after washing and desalting, thereby reducing the cement quality. While avoiding, the chlorine content can be stably removed from the cement production facility, and the amount of chlorine bypass dust D5 to be washed and desalted can be reduced.

DESCRIPTION OF SYMBOLS 1 Chlorine bypass extraction dust processing apparatus 2 Cement kiln 3 Probe 4 Cooling fan 5 Cyclone 6 Cooler 7 Cooling fan 8 Bag filter 9 Dust tank 10 Fan 11 Chlorine bypass extraction dust processing apparatus 12 Classifiers 13 and 14 Dust tank

Claims (3)

A part of the combustion exhaust gas is extracted from the kiln exhaust gas passage from the bottom of the kiln of the cement kiln to the lowermost cyclone of the preheater while cooling, separating the coarse powder from the extracted gas, and the extracted gas after the coarse powder separation A method of treating chlorine bypass bleed dust that collects fine powder from
A method for treating chlorine bypass bleed dust, wherein a part of fine powder separated from the bleed gas and coarse powder separated from the bleed gas are added to a cement clinker in a cement grinding step. The coarse powder separated from the extraction gas is classified according to the chlorine concentration,
The method for treating chlorine bypass bleed dust according to claim 1, wherein the fine powder obtained by classification is added to a cement clinker in a cement grinding step. A probe for extracting air while cooling a part of the combustion exhaust gas from the kiln exhaust gas flow path from the bottom of the kiln of the cement kiln to the lowermost cyclone of the preheater,
A classifier for separating the extracted gas from the probe into coarse powder, fine powder and gas;
A treatment of chlorine bypass bleed dust, comprising: an addition device for adding a part of the fine powder classified by the classification device and the coarse powder classified by the classification device to a cement clinker in a cement grinding process. apparatus.

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