JP2010227900A - Apparatus and method for treating exhaust gas of cement kiln - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove mercury contained in an exhaust gas of a cement kiln efficiently at a low cost. <P>SOLUTION: The apparatus 1 for treating the exhaust gas of a cement kiln includes a dispersing unit 3 for dispersing aggregates of particles in dust D1 contained in the exhaust gas of a cement kiln, a classifying unit 4 for classifying dust D2 in which the aggregates of particles are dispersed by the dispersing unit 3, a heating unit 5 for heating dust D4 containing fine particles classified by the classifying unit 4 and a mercury recovering unit 9 for recovering mercury vaporized by being heated by the heating unit 5. The classifying unit 4, which is a centrifugal type or an inertial type, can attain 10 μm or finer at its partial classification efficiency of 50%. A solid/gas separating unit 7 is provided which subjects an exhaust gas G1 from the heating unit 5 to solid/gas separation. The mercury recovering unit 9 can recover mercury from the gas G2 which is separated by the solid/gas separating unit 7 for treating the exhaust gas G1 from the heating unit 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an apparatus and a method for removing mercury from combustion exhaust gas discharged from a cement kiln constituting a cement firing facility.

  Cement kiln exhaust gas contains a trace amount of metallic mercury (Hg). Its origin is not only mercury contained in natural raw materials such as limestone, which is the main raw material of cement, but also mercury contained in a wide variety of recycled resources such as fly ash. In recent years, the recycling of wastes as cement raw materials and fuels has been promoted, and as the amount of waste processed increases, the mercury concentration in the cement kiln exhaust gas may increase.

  However, it is extremely difficult to remove a very small amount of mercury in cement kiln exhaust gas from a large amount of exhaust gas. If the amount of mercury in cement kiln exhaust gas increases, air pollution may occur and There is also a risk of hindering the expansion of the use of recycled resources such as ash.

  Therefore, for example, in Patent Document 1, after removing dust from the cement kiln exhaust gas with a dust collector, the collected dust is guided to a heating furnace, and the mercury in the dust is heated to a volatilization temperature or higher to volatilize. A method for treating cement production exhaust gas that is adsorbed and removed by an adsorbent or the like has been proposed.

  Patent Document 2 discloses a gravity dust collector (separation limit particle size: 50) from upstream to downstream of cement kiln exhaust gas based on the knowledge that harmful substances such as mercury are unevenly distributed on the fine powder side of dust collection dust. ~ 60μm), an inertial dust collector (separation limit particle diameter: 20 μm) and a centrifugal dust collector (separation limit particle diameter: 2 to 3 μm) are installed in this order to collect the dust on the fine powder side collected by the final stage dust collector A method for treating kiln exhaust gas is disclosed.

  Furthermore, this document focuses on the fact that toxic substances adhere to unburned carbon in dust collection dust, and after leaving the dust collection dust shaken in a container with organic solvent and water, the organic solvent layer The organic solvent layer separated and recovered from the liquid is subjected to several times of mixing with water, shaking, and separation to remove unburned carbon in the organic solvent. A processing method is also disclosed in which extraction is performed and then the organic solvent is evaporated to recover unburned carbon.

Japanese Patent Laid-Open No. 2002-355531 JP 2006-45006 A

  However, in the treatment method described in Patent Document 1, since dust collected from the cement kiln exhaust gas is directly introduced into the heating furnace, dust that does not need to be heated when removing mercury is also heat-treated at the same time. As a result, there is a problem that the processing efficiency decreases.

  On the other hand, in the processing method described in Patent Document 2, since the dust collection dust is not subjected to the heat treatment, it is possible to avoid a decrease in the treatment efficiency due to the heat treatment. However, the classifier is not used in this method and dust collectors are used for all, but the purpose of the dust collector is to reduce the amount of powder in the exhaust gas discharged from the dust collector. In addition, since the powder cannot be sufficiently classified, the dust on the coarse powder side collected by the dust collector naturally contains a large amount of fine powder. Therefore, since the coarse powder containing a large amount of fine powder is returned to the cement manufacturing process, harmful substances such as mercury may be further concentrated. Furthermore, since many dust collectors are installed, enormous apparatus cost will be required. On the other hand, even in the method of recovering unburnt carbon and removing harmful substances, an increase in the number of treatment steps and treatment time is unavoidable, and there is a risk of increasing the cost of chemicals. There is a problem of causing an increase.

  Then, this invention is made | formed in view of the problem in the said prior art, Comprising: It aims at removing the mercury in cement kiln exhaust gas efficiently at low cost.

  In order to achieve the above object, the present invention is a cement kiln exhaust gas treatment apparatus for dispersing particle aggregates in dust contained in cement kiln exhaust gas, and the particle aggregates dispersed by the dispersion apparatus. A classification device for classifying the collected dust, a heating device for heating the dust on the fine powder side classified by the classification device, and a mercury recovery device for recovering mercury volatilized by the heating by the heating device. .

  And according to the present invention, by performing the classification operation after dispersing the particle aggregate in the dust contained in the exhaust gas of the cement kiln, the dust having a high mercury content is selectively maintained while maintaining high classification efficiency. Since the mercury removal process is performed on the dust that is taken out, it is possible to perform the removal process in a state where unnecessary dust unnecessary for mercury removal is removed in advance. Therefore, a large amount of cement kiln exhaust gas can be processed in a short time, or the facility scale can be reduced, so that it is possible to improve the processing efficiency and reduce the processing cost.

  In the cement kiln exhaust gas treatment apparatus, a centrifugal classifier or an inertial classifier can be used as the classifier. In addition, the particle size of the classification device at which the partial classification efficiency is 50% (the particle size at which the partial classification efficiency is 50% is hereinafter referred to as “50% separation particle size (D50)”) is at least 10 μm. It can be set as the classification apparatus which has the following performance.

  Further, the present invention is a cement kiln exhaust gas treatment device, a dispersion / classification device for classifying the dust in which the particle aggregates are dispersed while dispersing the particle aggregates in the dust contained in the exhaust gas of the cement kiln, A heating device for heating dust on the fine powder side classified by the dispersing / classifying device, and a mercury recovery device for recovering mercury volatilized by heating by the heating device are provided. According to the present invention, as in the case of the above-described invention, a large amount of cement kiln exhaust gas can be treated in a short time by performing the removal treatment in a state in which excess dust unnecessary for mercury removal is removed in advance, or The scale can be reduced, and the processing efficiency can be improved and the processing cost can be reduced.

  The cement kiln exhaust gas treatment apparatus includes a solid-gas separation device for solid-gas separation of the exhaust gas from the heating device, and the mercury recovery device may recover mercury from the gas separated by the solid-gas separation device. it can. According to this configuration, mercury can be recovered from the exhaust gas without being hindered by the presence of dust.

  In the cement kiln exhaust gas treatment apparatus, the heating apparatus can heat the dust on the fine powder side classified by the classification apparatus to 400 ° C. or more and 600 ° C. or less. According to this, mercury in dust on the fine powder side can be volatilized under optimum volatilization conditions, and much of the volatilized mercury can be retained in the exhaust gas.

  The cement kiln exhaust gas treatment apparatus may include a hot air generator that generates hot air independently from the cement kiln and supplies the generated hot air to the heating device.

  As a heat source of the heating device, it may be possible to use high-temperature gas generated during the operation of the cement kiln. In that case, in addition to the possibility of deteriorating the thermal efficiency of the cement kiln, Since it is not generated for the purpose of heating, it does not always satisfy an appropriate temperature condition, and there is a possibility that a desired heating efficiency cannot be obtained. In contrast, the above configuration requires additional equipment and fuel costs, but there is no risk of adverse effects on cement production, and the temperature can be adjusted freely. Processing can be performed.

  In the cement kiln exhaust gas treatment apparatus, the hot air generator can generate the hot air using combustible waste as at least a part of the fuel, thereby reducing fuel costs and effectively utilizing resources. Can contribute.

  In the cement kiln exhaust gas treatment apparatus, it is possible to provide a route for returning the dust on the coarse powder side classified by the classifier to the cement kiln, whereby the dust from which mercury has been removed can be used as a cement raw material. it can.

  Further, the present invention is a method for treating cement kiln exhaust gas, wherein the particle aggregate in the dust contained in the exhaust gas of the cement kiln is dispersed, the dust in which the particle aggregate is dispersed is classified, and obtained by the classification. The dust on the fine powder side is heated, and mercury volatilized from the dust on the fine powder side by the heating is recovered. According to the present invention, as in the case of the above-described invention, a large amount of cement kiln exhaust gas can be treated in a short time by performing the removal treatment in a state in which excess dust unnecessary for mercury removal is removed in advance, or The scale can be reduced, and the processing efficiency can be improved and the processing cost can be reduced.

  As described above, according to the present invention, mercury in cement kiln exhaust gas can be efficiently removed at low cost.

It is a flowchart which shows 1st Embodiment of the processing apparatus of the cement kiln exhaust gas concerning this invention. It is a schematic sectional drawing which shows the pin type disperser as an example of the dispersing device used for the processing apparatus of the cement kiln exhaust gas of FIG. It is a flowchart which shows 2nd Embodiment of the processing apparatus of the cement kiln exhaust gas concerning this invention. FIG. 4 is a diagram showing a crusher (registered trademark, manufactured by Taiheiyo Engineering Co., Ltd., a trade name) as an example of a dispersion / classification device used in the cement kiln exhaust gas treatment device of FIG. 3, (a) is a perspective perspective view; (B) is front sectional drawing. FIG. 4 is a partial classification efficiency curve with and without a dispersion function of a dispersion / classification device used in the cement kiln exhaust gas treatment device of FIG. 3.

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

  FIG. 1 shows a first embodiment of a cement kiln exhaust gas treatment apparatus according to the present invention. This treatment apparatus 1 is roughly divided into an electrostatic precipitator 2 disposed in a subsequent stage of a cement kiln (not shown), The dispersion device 3 for dispersing the particle aggregates in the dust collection dust D1 collected by the dust collector 2 and the dust D2 in which the particle aggregates are dispersed by the dispersion device 3 are classified, and the coarse powder side dust D3 and the fine powder side dust D4 are classified. Is included in the classification device 4 for obtaining the heat, the heating device 5 for heating the fine dust D4, the hot air generator 6 for supplying hot air to the heating device 5, the exhaust gas G1 discharged from the heating device 5, and the exhaust gas G1. A solid-gas separation device 7 that separates the dust D5 from solid and gas, a mercury recovery device 9 that collects mercury from the exhaust gas G2 after the solid-gas separation, and the like are configured.

  The dispersing device 3 is provided to disperse the particle aggregates in the dust collection dust D1 collected by the electric dust collector 2. As an example of the dispersing device 3, a pin type dispersing device 13 as shown in FIG. Can be used. The pin-type disperser 13 is erected around the outer edge of a supply chute 13a, a plurality of fixing pins 13c fixed to the inner wall of the container 13b, and a circular rotating plate 13e integrated with the rotating shaft 13d. It is composed of a plurality of rotating pins 13f and 13g that rotate close to the fixed pin 13c so as to sandwich the pin 13c, and a motor 13h that rotates the rotating shaft 13d, and the outermost rotating pin 13g is 5 m / s or more. Rotates at a peripheral speed of.

  Returning to FIG. 1, the classifier 4 is provided to separate the dust D2 in which the particle aggregates are dispersed by the dispersing device 3 into the coarse powder side dust D3 and the fine powder side dust D4. A classifier or the like can be used. The classifier 4 has a performance such that the 50% separated particle size (D50) is at least 10 μm or less, and collects the coarse powder side dust D3 while supplying the fine powder side dust D4 to the heating device 5 in the next stage. . This is based on the knowledge that most of the mercury is unevenly distributed on the fine powder side of the dust collection dust D1, and only the portion containing a large amount of mercury from the dust collection dust D1 by the classification process. It can be selectively extracted.

  The heating device 5 is a heating furnace or the like that heats the fine powder side dust D4, and is provided for volatilizing mercury contained in the fine powder side dust D4. In the heating device 5, in order to volatilize mercury in the fine powder side dust D4 efficiently, the fine powder side dust D4 is preferably heated to 400 ° C. or higher and 600 ° C. or lower, and further heated to 550 ° C. or higher and 600 ° C. or lower. More preferred.

  The hot air generator 6 is provided as a heat source for the heating device 5 and generates hot air by burning predetermined fuel. From the viewpoint of reducing fuel costs and effective use of resources, the hot air generator 6 uses combustible waste such as waste oil and waste solvent as the main fuel, and only uses natural fuel such as heavy oil and kerosene as an auxiliary. .

  The solid-gas separator 7 is desirably a high heat-resistant bag filter having heat resistance up to about 900 ° C. Various types of bag filters have been developed, such as those in which a plurality of rod-shaped ceramic tubes formed into honeycomb cells are arranged, and those using sheet-like ceramic filters. The type of filter is not particularly limited as long as dust D5 contained in the exhaust gas G1 can be collected. An induction fan 8 is provided at the subsequent stage of the solid-gas separation device 7.

  On the other hand, the solid-gas separation device 7 can also be a bag filter provided with filter cloths corresponding to various heat-resistant temperatures by adjusting the temperature of the exhaust gas G1. In that case, a temperature control device is provided in front of the bag filter. In addition, avoid recondensation of volatile mercury contained in the exhaust gas G1, and consider that the filter cloth having heat resistance next to the filter cloth made of ceramic is generally a filter cloth made of glass fiber. Then, it is preferable to adjust the temperature of exhaust gas G1 to 150-250 degreeC, and it is more preferable to adjust to 180-230 degreeC.

  The mercury recovery device 9 is provided for receiving the combustion exhaust gas G2 after collecting the dust D6 and removing mercury from the combustion exhaust gas G2. As the mercury recovery device 9, a gas adsorption device that adsorbs and removes mercury with a general adsorbent can be used. More specifically, a porous adsorption medium such as activated carbon or activated coke is fixed as a dry method. A method of adsorbing and removing mercury contained in gas by filling a layer type or moving bed type device and passing it through gas, a medium that selectively adsorbs mercury such as chelate resin, etc. There is a method of adsorbing and removing mercury contained in the gas by passing mercury through it, and as a wet method, the mercury-containing gas is washed by a wet cleaning device such as a scrubber or a spray tower, A method of recovering mercury on the liquid phase side can be used. In addition, a coagulation precipitation method by deep cooling of a mercury-containing gas can also be used.

  Next, the operation of the cement kiln exhaust gas treatment apparatus 1 having the above-described configuration will be described with reference to FIGS. 1 and 2.

  First, the cement kiln exhaust gas is collected by the electric dust collector 2, and the collected dust collection dust D 1 is introduced into the dispersing device 3. In the pin-type disperser 13 (dispersing device 3) shown in FIG. 2, the dust collecting dust D1 supplied into the container 13b from the supply chute 13a has an impact force between the fixed pin 13c and the rotating pins 13f and 13g. A shearing force is applied, and the particle aggregates in the dust collection dust D1 are dispersed.

  Returning to FIG. 1, the dust D2 in which the particle aggregates are dispersed by the dispersing device 3 is introduced into the classifying device 4, and the dust D2 is classified by the classifying device 4 and separated into the coarse powder side dust D3 and the fine powder side dust D4. After collection, the coarse powder side dust D3 is returned to the cement process and reused as a cement raw material or the like, and the fine powder side dust D4 is conveyed to the heating device 5 to remove mercury.

  Next, the fine powder side dust D4 is heated to 400 ° C. or higher and 600 ° C. or lower using hot air from the hot air generator 6 to volatilize mercury in the fine powder side dust D4. Thereafter, the solid gas separation device 7 solid-gas separates the exhaust gas G1 and dust D5 discharged from the heating device 5, and collects the dust D5. The dust D6 discharged from the solid gas separation device 7 is returned to the cement process and reused as a cement raw material or the like, and the exhaust gas G2 of the solid gas separation device 7 is conveyed to the mercury recovery device 9 through the induction fan 8.

  Next, in the mercury recovery device 9, mercury contained in the exhaust gas G2 is removed using a wet gas absorption device. The mercury G3 from which mercury has been removed and detoxified in the mercury recovery device 9 is released into the atmosphere or returned to the cement process for heat recovery.

  As described above, in the present embodiment, after dispersing the particle aggregates in the dust collection dust D1 by the dispersing device 3, the classification operation is performed by the classifying device 4, so that mercury is maintained while maintaining high classification efficiency. Since the fine dust side dust D4 having a high content is selectively taken out and the mercury removal process is performed on the fine dust side dust D4, the extra dust unnecessary for mercury removal is removed in advance. be able to. Therefore, a large amount of cement kiln exhaust gas can be processed in a short time, or the facility scale can be reduced, thereby improving the processing efficiency and reducing the processing cost.

  In the above embodiment, the electrostatic precipitator 2 is arranged at the subsequent stage of the cement kiln. Instead of the electric precipitator 2, a bag filter, a cyclone, a mobile dust collector, etc. are arranged, and the dust collected by these dust collectors is collected. Dust may be introduced into the dispersing device 3.

  Further, as the dispersing device 3, the pin type disperser 13 provided with a plurality of rotating pins 13f and 13g that rotate in the vicinity of the fixing pin 13c with the fixing pin 13c interposed therebetween is illustrated, but two rotating shafts are illustrated. In addition, a pin type disperser that includes a plurality of rotating pins that rotate together with the respective rotating shafts and that has a relative peripheral speed by rotation of the rotating pins of 5 m / s or more at the maximum position can also be used.

  Further, in addition to the pin type disperser 13, an ejector having a gas supply pressure of 100 kPa to 600 kPa as a gauge pressure, a dispersion pipe having a gas flow with a Reynolds number of 12000 or more, a projection attached to a rotating shaft or the like. It is also possible to supply the dust D1 to a container having a rotating body whose outermost portion rotates at a peripheral speed of 5 m / s or more and disperse the particle aggregates in the dust D1. In addition, the dust D1 is supplied to a container filled with balls having a sphere equivalent diameter of 1 mm to 60 mm as a dispersion medium, and the container is rotated, for example, so that the rotating shaft installed inside the container and the stirring blade joined thereto The particle aggregate in the dust D1 can be dispersed by rotating the dispersion medium and the like to move the dispersion medium.

  Furthermore, by using an adsorption device using activated carbon, activated coke, or the like for the mercury recovery device 9, in addition to mercury, harmful substances represented by organic chlorine compounds such as trace amounts of dioxins and PCBs contained in the combustion exhaust gas G1 Can be adsorbed and removed.

  Next, a second embodiment of the cement kiln exhaust gas treatment apparatus according to the present invention will be described with reference to FIGS.

  The cement kiln exhaust gas treatment apparatus 21 according to the present embodiment can perform both functions of dispersion and classification in place of the dispersion apparatus 3 and the classification apparatus 4 of the treatment apparatus 1 shown in FIG. Dispersion / classification device 24 is provided. Since the other components of the cement kiln exhaust gas treatment device 21 are the same as those of the treatment device 1 shown in FIG. 1, the same reference numerals as those of the treatment device 1 shown in FIG. Description is omitted.

  The dispersion / classification device 24 is provided to classify the dust in which the particle aggregates are dispersed while dispersing the particle aggregates in the dust collection dust D1 collected by the electric dust collector 2, and the dispersion / classification device 24 is provided. As an example, a dispersing / classifying device (crush seal) 24 as shown in FIG. 4 can be used.

  The dispersion / classification device 24 includes a classification chamber 32 in a cylindrical upper casing 31, and a classification rotor 40 that is rotated by a motor 36 via a rotation shaft 35 is provided in the classification chamber 32. The classification rotor 40 includes a large number of classification blades 41. A disc-shaped dispersion plate 33 is provided on the ceiling portion of the classification rotor 40. A feed chute 37 is connected to the ceiling portion of the upper casing 31, and a first air duct 38 and a second air duct 39 are provided on the side surface of the upper casing 31. A large number of guide vanes 34 are arranged along the inner wall of the upper casing 31, and a lower cone 45 to which tertiary air ducts 43 and 44 are connected is provided below the upper casing 31. A discharge bend 46 is connected to the ceiling portion of the classification chamber 32, and the discharge bend 46 extends upward through the ceiling portion of the upper casing 31. The lower end of the lower cone 45 opens as a coarse powder outlet 47.

  In the dispersion / classification device 24, the dust collection dust D <b> 1 supplied from the feed chute 37 is dispersed by the dispersion plate 33 on the ceiling portion of the classification rotor 40 and is scattered on the outer peripheral portion of the dispersion plate 33 by the centrifugal force of the dispersion plate 33. And falls into the classification chamber 32.

  The dust collection dust D1 that has fallen into the classification chamber 32 is the same as the dust collection dust D1 in which the particle aggregates are dispersed after the particle aggregates in the dust collection dust D1 are dispersed by the free vortex formed by the guide vanes 34. Under the combined use of the free vortex (primary classification) and the forced vortex (secondary classification) by the classification rotor 40 rotating at high speed, the swirl motion is performed along the rotation direction of the classification rotor 40. By this turning motion, classification is performed by a balance between the centrifugal force acting on the dust collection dust D1 and the drag force caused by the air flow toward the inner surface of the classification rotor 40.

  The classified fine particles are discharged from the discharge bend 46 in an air current, and are conveyed to the heating device 5 as fine powder side dust D4 shown in FIG. On the other hand, the coarse particles fall to the lower cone 45 due to gravity and are collected from the coarse powder outlet 47 as the coarse powder side dust D3.

  The operation after the heating device 5 in FIG. 3 is the same as that in the first embodiment shown in FIG. 1. Finally, the mercury recovery device 9 removes mercury contained in the exhaust gas G2 of the solid-gas separation device 7. To do.

  In the present embodiment, a case where a crusher is used as the dispersing / classifying device 24 is exemplified, but in addition, an air separator with a cyclone, O-SEPA (registered trademark, manufactured by Taiheiyo Engineering Co., Ltd., trade name) It is also possible to use a dispersing / classifying apparatus such as

  When the gap G between the side surface of the classification rotor 40 and the inner wall of the upper casing 31 shown in FIG. 4B is adjusted using the dispersion / classification device 24 shown in FIG. The dispersion / classification device 24 has a dispersion function) and the gap G is 50 mm (in this case, the dispersion / classification device 24 does not have a dispersion function). The classification characteristics of dust dust were compared. The result is shown in FIG. The dust collection dust used in the examples is dust collection dust collected from an exhaust gas from a cement kiln without an apparatus for removing mercury by an electric dust collector (particles of 4 μm or less contain 90% or more of mercury). ).

  From the figure, when the gap G is 20 mm (with dispersion function), the distribution ratio to the coarse powder side is 25% for the particle size of 1 μm and 50% for the 4 μm, whereas the gap G is 50 mm (dispersion). In the case of no function), it was 65% at 1 μm and 90% at 4 μm. As a result, there is also a difference in the mercury recovery rate on the fine powder side, and when the ratio of the amount of mercury recovered on the fine powder side in the initial amount of mercury in the dust collection dust was determined, the gap G was 20 mm (dispersion function In the case of the present), it was 64% by mass, whereas in the case where the gap G was 50 mm (without the dispersion function), it was 28% by mass. From the above, it can be seen that by providing the dispersing function, the mercury recovery rate to the fine powder side can be further increased, and the efficiency of removing mercury in the cement kiln exhaust gas can be increased.

DESCRIPTION OF SYMBOLS 1 Cement kiln exhaust gas processing device 2 Electric dust collector 3 Dispersing device 4 Classification device 5 Heating device 6 Hot air generating device 7 Solid air separating device 8 Induction fan 9 Mercury recovery device 13 Pin type disperser 13a Supply chute 13b Container 13c Fixed pin 13d Rotation Shaft 13e Rotating plate 13f Rotating pin 13g Rotating pin 13h Motor 21 Cement kiln exhaust gas treatment device 24 Dispersing / classifying device 31 Upper casing 32 Classification chamber 33 Dispersing plate 34 Guide vane 35 Rotating shaft 36 Motor 37 Feed chute 38 First air duct 39 Second air duct 40 Classification rotor 41 Classification blade 43 Tertiary air duct 44 Tertiary air duct 45 Lower cone 46 Discharge bend 47 Coarse powder discharge port

Claims (8)

A dispersion device for dispersing particle aggregates in dust contained in the exhaust gas of the cement kiln;
A classifying device for classifying dust in which particle aggregates are dispersed by the dispersing device;
A heating device for heating dust on the fine powder side classified by the classification device;
A cement kiln exhaust gas treatment apparatus comprising: a mercury recovery apparatus that recovers mercury volatilized by heating by the heating apparatus.   The classifier is a centrifugal classifier or an inertial classifier, and the particle size at which the partial classification efficiency of the classifier is 50% is at least 10 μm or less. The cement kiln exhaust gas treatment apparatus as described. A dispersion / classification device for classifying the dust in which the particle aggregates are dispersed while dispersing the particle aggregates in the dust contained in the exhaust gas of the cement kiln;
A heating device for heating the dust on the fine powder side classified by the dispersing / classifying device;
A cement kiln exhaust gas treatment apparatus comprising: a mercury recovery apparatus that recovers mercury volatilized by heating by the heating apparatus. A solid-gas separation device for solid-gas separation of the exhaust gas from the heating device;
4. The cement kiln exhaust gas treatment device according to claim 1, wherein the mercury recovery device recovers mercury from the gas separated by the solid-gas separation device.   5. The cement kiln exhaust gas treatment apparatus according to claim 4, wherein the heating device heats the dust on the fine powder side classified by the classification device or the dispersion / classification device to 400 ° C. or more and 600 ° C. or less. .   A hot air generator that generates hot air independently from the cement kiln and supplies the generated hot air to the heating device, the hot air generator using the combustible waste as at least a portion of fuel; The cement kiln exhaust gas treatment apparatus according to any one of claims 1 to 5, wherein:   The cement kiln exhaust gas treatment apparatus according to any one of claims 1 to 6, further comprising a route for returning the dust on the coarse powder side classified by the classification device or the dispersion / classification device to the cement kiln. Disperse the particle aggregates in the dust contained in the exhaust gas of the cement kiln,
Classifying the dust in which the particle aggregates are dispersed;
The dust on the fine powder side obtained by the classification is heated,
A method for treating a cement kiln exhaust gas, comprising recovering mercury volatilized from the dust on the fine powder side by the heating.

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