JP6586032B2 - Exhaust gas treatment method and apparatus - Google Patents

Description

  The present invention relates to an exhaust gas treatment method and apparatus that can reduce the amount of chemicals such as slaked lime that are required for the treatment of exhaust gas in a waste incineration facility.

  In order to reduce wastes such as municipal waste efficiently and hygienically, waste is incinerated by an incinerator. Since the exhaust gas discharged from the incinerator contains acidic gas such as hydrogen chloride (HCl) sulfur oxide (SOx), chemicals such as slaked lime are blown into the exhaust gas, and HCl and SOx are below the standard value for acid gas emission. It is suppressed to. In municipal waste incineration facilities, an increasing number of local governments set the acid gas emission standard value of HCl and SOx to 10 ppm or less. When the acid gas emission reference value is severe, there is a problem that the amount of chemicals used is excessive in a simple process by blowing slaked lime.

In order to reduce the amount of chemical used, increase the reactivity of the chemical, or fly ash collected by a bag filter after blowing the chemical into the exhaust gas (including reaction products of acid gas and chemical, unreacted chemical) Need to be reused.
In order to increase the reactivity of the drug, a method of humidifying fly ash has been put into practical use, and this method is mainstream in Europe. However, this method of humidifying the fly ash has a problem that it is difficult to control, and it has a problem that it is effective only in the case of a large furnace because the equipment is complicated.
There are two methods for reusing (recycling) fly ash: a method of simply returning fly ash, and a method of classifying fly ash, discarding small sized particles, and pulverizing large sized particles. is there. However, in any method, when the amount of ash reuse increases, the concentration of post-reaction substances (CaClOH, CaCl ₂ ) increases, and moisture absorption, deliquescence trouble (the ash bridges in the cold parts inside the drug transport tube and bag filter, It is expected that there will be an upper limit on the amount of ash circulation.

Japanese Patent No. 5612886

  The present invention has been made in view of the above-described circumstances, and can reduce the amount of chemicals such as slaked lime necessary for the treatment of exhaust gas, and reduce LCC (life cycle cost) while satisfying strict acid gas emission standard values. An object is to provide an exhaust gas treatment method and apparatus.

In order to achieve the above-described object, the first aspect of the present invention, after adding an exhaust gas treatment agent made of powder to the exhaust gas discharged from the waste incineration facility, and removing the acidic gas in the exhaust gas, An exhaust gas treatment method for collecting exhaust ash in exhaust gas by passing the exhaust gas through a bag filter, wherein the fly ash collected by the bag filter is guided to a surface polishing machine for surface polishing, and the fly ash after surface polishing the led to the classification device by fly ash and secondary classifying the fly ash and other particle size of a given particle diameter, to return the fly ash of the predetermined particle size to exhaust gas upstream of the bag filter, the surface polishing machine Is a vibratory mill that performs surface polishing of fly ash by housing fly ash and polishing medium in a container-shaped drum, vibrating the drum, and rubbing the fly ash particles with each other or the fly ash particles and the polishing medium. The classifier has a rotary valve at the bottom. Characterized in that it consists example was the cyclone.

According to a preferred aspect of the present invention, the fly ash having the predetermined particle diameter is fly ash having an average particle diameter of 4 μm to 10 μm.
According to a preferred aspect of the present invention, the exhaust gas treatment chemical is slaked lime .
According to a preferred aspect of the present invention, the cyclone is composed of a plurality of cyclones, and the separation limit particle size of the first cyclone among the plurality of cyclones is set to 10 μm.
According to a preferred aspect of the present invention, the separation limit particle diameter of the second-stage cyclone among the plurality of cyclones is set to 4 μm.
According to an embodiment of the present invention, the surface polishing machine rather guide the fly ash that is collected by the bag filter after removing the fly ash with a large particle size is guided to the second classifying device.
According to an embodiment of the present invention, the second classifying device, Ru least one stage cyclone Tona.
According to a preferred aspect of the present invention, the fly ash flow path for conveying the fly ash that has been surface polished by the surface polishing machine to the downstream side is heated and kept warm.

According to a second aspect of the present invention, an exhaust gas treatment agent made of powder is added to the exhaust gas discharged from a waste incineration facility to remove acid gas in the exhaust gas, and then the exhaust gas is passed through a bag filter to remove the exhaust gas. An exhaust gas treatment apparatus for collecting fly ash in the surface, a surface polishing machine for polishing the surface of the fly ash collected by the bag filter, and a fly ash that has been polished by the surface polishing machine with a predetermined particle size. A classifying device for classifying the fly ash into other fly ash having a particle size, and a fly ash returning unit for returning the fly ash having a predetermined particle size classified by the classifier to the exhaust gas upstream of the bag filter. The surface polishing machine accommodates fly ash and polishing medium in a container-shaped drum, vibrates the drum, and rubs the fly ash particles or the fly ash particles with the polishing medium to polish the fly ash surface. The classifying device comprises: Characterized by comprising the cyclone provided with a rotary valve.

According to a preferred aspect of the present invention, the fly ash having the predetermined particle diameter is fly ash having an average particle diameter of 4 μm to 10 μm.
According to a preferred aspect of the present invention, the exhaust gas treatment chemical is slaked lime .
According to a preferred aspect of the present invention, the cyclone is composed of a plurality of cyclones, and the separation limit particle size of the first cyclone among the plurality of cyclones is set to 10 μm.
According to a preferred aspect of the present invention, the separation limit particle diameter of the second-stage cyclone among the plurality of cyclones is set to 4 μm.
According to an embodiment of the present invention, the second classifying device for classifying and removing the large ash fly ash from the fly ash collected by the bag filter is provided, and after removing the large ash fly ash The fly ash was guided to the surface polishing machine .
According to an embodiment of the present invention, the second classifying device, Ru least one stage cyclone Tona.
According to a preferred aspect of the present invention, the fly ash flow path for conveying the fly ash that has been surface polished by the surface polishing machine to the downstream side is heated and kept warm.

The present invention has the following effects.
(1) The amount of chemicals such as slaked lime required for the treatment of exhaust gas can be reduced while meeting strict acid gas emission standard values in waste incineration facilities.
(2) LCC (life cycle cost) including ash processing amount, chemical unit price, chemical usage, equipment initial, maintenance cost, etc. can be reduced.

FIG. 1 is a schematic diagram showing a basic concept of an exhaust gas treatment method according to the present invention. FIG. 2 is a diagram schematically showing the fly ash surface polishing step. 3 (a) and 3 (b) are particle size distributions, which are indices indicating what size (particle diameter) of particles are contained and in what proportion (relative particle amount with 100% as a whole). FIG. 3A shows the particle size distribution of fly ash (bag ash) discharged from the bag filter, and FIG. 3B shows the particle size distribution of special slaked lime used for processing. FIG. 4 is a schematic view showing the first embodiment of the exhaust gas treatment apparatus according to the present invention. FIG. 5 is a schematic view showing a second embodiment of the exhaust gas treatment apparatus according to the present invention.

Hereinafter, embodiments of an exhaust gas treatment method and apparatus according to the present invention will be described with reference to FIGS. 1 to 5. 1 to 5, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is a schematic diagram showing a basic concept of an exhaust gas treatment method and apparatus according to the present invention. As shown in FIG. 1, the flue gas discharged from the incinerator is sprayed with powdered slaked lime (Ca (OH) ₂ ) from the slaked lime supply unit 2 while flowing through the exhaust gas introduction unit (flue) 1. After that, it is introduced into the bug filter 3. By removing the slaked lime onto the combustion exhaust gas, an acid gas such as HCl and SOx in the combustion exhaust gas is removed. In this case, since a filter layer of slaked lime is formed on the filter cloth surface of the bag filter 3, a high removal rate can be obtained. The fly ash in the combustion exhaust gas is captured by the bag filter 3. The treated exhaust gas discharged from the bag filter 3 is discharged outside through the chimney by an induction fan. The incinerator may be a fluidized bed incinerator or a stoker furnace, and any incineration type may be used.

The fly ash captured by the bag filter 3 contains reaction products such as CaCl ₂ and CaClOH and unreacted slaked lime. Therefore, in the exhaust gas treatment method of the present invention, the fly ash discharged from the bag filter 3 is guided to the surface polishing machine 4, and the surface polishing machine 4 performs surface polishing of the fly ash to expose the unreacted slaked lime portion.

FIG. 2 is a diagram schematically showing the fly ash surface polishing step. As shown in FIG. 2, the fly ash discharged from the bag filter 3 contains a large number of fly ash particles in which reaction products such as CaCl ₂ and CaClOH are attached to the unreacted slaked lime portion. FIG. 2 shows fly ash particles in which reaction products (CaCl ₂ , CaClOH) are attached to unreacted slaked lime. Since the reactivity is poor when the reaction product is attached to the surface, as shown in FIG. 2, the fly ash particles remove the reaction product in the surface polishing step by the surface polishing machine 4 and remove the surface of the unslaked lime particles. Need to be exposed. Even when fly ash particles are partially broken in the surface polishing step, the surface of unreacted slaked lime appears, so that slaked lime can be reused. FIG. 2 shows an example of slaked lime particles from which all reaction products have been removed by surface polishing, but actually, fly ash after surface polishing contains a large amount of reaction products such as CaCl _2. Reaction product rich fly ash and slaked lime rich fly ash containing a large amount of slaked lime are included.

As shown in FIG. 1, the fly ash after surface polishing is guided to a classifier 5, and the classifier 5 classifies the fly ash. In this classification step, slaked lime-rich fly ash having a particle size of 4 to 10 μm (average particle size) and other ash-rich rich fly ash having a particle size of 4 to 10 μm are classified. It returns to the exhaust gas introduction part (flue) 1 through the return part 6. In other words, by selectively removing unreacted slaked lime with high purity by classification and reusing it, the amount of slaked lime used is reduced while suppressing deliquescence problems due to CaCl ₂ , moisture absorption problems due to CaClOH, and filter cloth clogging. it can. The classification device 5 may be composed of a plurality of classification means (for example, a cyclone), and at least one classification means (for example, a cyclone) among the plurality of classification means is provided upstream of the surface polishing machine 4. You may arrange.

Next, the reason why only the slaked lime rich fly ash having a particle diameter of 4 to 10 μm (average particle diameter) is returned to the exhaust gas introduction unit 1 and reused will be described.
3 (a) and 3 (b) are particle size distributions, which are indices indicating what size (particle diameter) of particles are contained and in what proportion (relative particle amount with 100% as a whole). FIG. 3A shows the particle size distribution of fly ash (bag ash) discharged from the bag filter, and FIG. 3B shows the particle size distribution of special slaked lime used for processing. 3A and 3B, the horizontal axis represents the particle diameter (μm), and the vertical axis represents the volume ratio (%).

  In the basic concept of the present invention shown in FIGS. 1 and 2, an example using special slaked lime for the treatment of exhaust gas is shown. It can be seen from FIG. 3B that the special slaked lime has a large proportion of particle diameters of about 1 to 10 μm. Therefore, when exhaust gas treatment is performed using special slaked lime, fly ash having a particle diameter of about 1 to 10 μm is considered to be slaked lime-rich fly ash containing a large amount of slaked lime. As shown in FIG. 3 (a), fly ash (bag ash) discharged from the bag filter has a large particle size of 10 μm or more, but this large particle size fly ash has a small amount of unreacted slaked lime. Discard it. On the other hand, fly ash having a small particle size of less than 4 μm contains a large amount of reaction products and, when reused (recirculated), causes clogging of the filter cloth of the bag filter and is discarded. Therefore, only the fly ash having a particle diameter of 4 to 10 μm is sorted and reused by classification.

Next, specific embodiments of the present invention based on the basic concept shown in FIGS. 1 and 2 will be described.
FIG. 4 is a schematic view showing the first embodiment of the exhaust gas treatment apparatus according to the present invention. As shown in FIG. 4, the exhaust gas introduction unit 1, the slaked lime supply unit 2, the bag filter 3, and the surface polishing machine 4 have the same configuration as that shown in FIG. In the first embodiment shown in FIG. 4, the fly ash discharged from the bag filter 3 is supplied to the surface polishing machine 4 via the screw feeder 11 and the rotary valve 12. The rotary valve 12 may be replaced with a double damper.

  The surface polishing machine 4 is composed of, for example, a vibration mill, and is a machine that rubs particles or particles and steel balls (polishing media) and generates shearing force on the surface of the particles. Function can be expected. Since the ball mill and the rod mill are pulverized, the surface polishing function cannot be expected. Moreover, the surface polishing function cannot be expected only by mixing with a mixer. As long as the surface polishing machine 4 is a machine that generates a shearing force on the surface of the particles, any method can be used, but a method using a vibration mill satisfies the needs for surface polishing of fly ash most.

  A vibration mill, which is an example of the surface polishing machine 4, contains a large number of steel balls as polishing media in a drum that is a cylindrical container. Fly ash is introduced into the drum from the inlet, and the entire drum is vibrated up and down, left and right, and the fly ash particles are rubbed together with each other or by rubbing the fly ash particles with the steel ball as a polishing medium. Surface polishing is performed.

In this way, fly ash surface polishing is performed by the surface polishing machine 4 made of a vibration mill to remove reaction products such as CaCl ₂ adhering to unreacted slaked lime. As shown in FIG. 4, the fly ash after surface polishing is discharged to the hopper 13. A fixed amount feeder 14 is installed at the bottom of the hopper 13, and the fly ash in the hopper 13 is quantitatively discharged by the constant amount feeder 14. The fly ash quantitatively discharged by the fixed amount feeder 14 is conveyed to the first cyclone 17 by the airflow sent from the blower (blower) 15. A heater 23 is installed on the outlet side of the blower 15 to heat the air discharged from the blower 15. The fly ash flow path is also kept warm. The separation limit particle size of the first cyclone 17 is set to 10 μm. Therefore, the fly ash is separated into fly ash having a large particle size larger than 10 μm and medium ash and small particle fly ash having a particle size of 10 μm or less by the centrifugal separation action of the first cyclone 17. Accumulates at the bottom of the first cyclone 17, and fly ash having a medium particle size and a small particle size is conveyed from the top of the first cyclone 17 to the second cyclone 18.

The large particle size fly ash accumulated in the first cyclone 17 has a small amount of unreacted slaked lime, and is discarded to the fly ash treatment facility via the rotary valve 17a. The separation limit particle diameter of the second cyclone 18 is set to 4 μm. Therefore, the medium and small particle size fly ash conveyed to the second cyclone 18 has a medium particle size fly ash of 4 to 10 μm and a small particle size of less than 4 μm due to the centrifugal separation action of the second cyclone 18. The fly ash is separated into fly ash, and the fly ash having a medium particle diameter is accumulated at the bottom of the second cyclone 18, and the fly ash having a small particle diameter is conveyed from the upper part of the second cyclone 18 to the mini bag filter 19. Since the fly ash having a medium particle diameter of 4 to 10 μm accumulated at the bottom of the second cyclone 18 is slaked lime-rich fly ash, it is returned to the exhaust gas introduction unit 1 before the bag filter 3 through the rotary valve 18a. The small particle fly ash discharged from the second cyclone 18 and captured by the mini bag filter 19 is a reaction product rich fly ash containing a large amount of reaction products such as CaCl ₂ , and the filter cloth of the bag filter 3. Since it causes clogging, it is discarded to the fly ash treatment facility via the rotary valve 19a.

  As can be seen from the description of FIG. 4, the first cyclone 17 and the second cyclone 18 correspond to the classification device 5 shown in FIG. 1. The separation limit particle diameter in the first cyclone 17 and the second cyclone 18 can be changed by adjusting the air volume of the blower 15. If there is a concern about clogging of the mini bag filter 19, a water scrubber or a resin sintered filter may be used.

  FIG. 5 is a schematic view showing a second embodiment of the exhaust gas treatment apparatus according to the present invention. As shown in FIG. 5, the exhaust gas introduction unit 1, the slaked lime supply unit 2, the bag filter 3 and the surface polishing machine 4 have the same configuration as that shown in FIG. In the second embodiment shown in FIG. 5, the fly ash discharged from the bag filter 3 is supplied to the hopper 13 via the screw feeder 11 and the rotary valve 12. The rotary valve 12 may be replaced with a double damper. A fixed amount feeder 14 is installed at the bottom of the hopper 13, and the fly ash in the hopper 13 is quantitatively discharged by the constant amount feeder 14. The fly ash quantitatively discharged by the fixed amount feeder 14 is conveyed to the first cyclone 17 by the airflow sent from the blower (blower) 15. A heater 23 is installed on the outlet side of the blower 15 to heat the air discharged from the blower 15. The fly ash flow path is also kept warm. The separation limit particle size of the first cyclone 17 is set to 10 μm. Therefore, the fly ash is separated into fly ash having a large particle size larger than 10 μm and medium ash and small particle fly ash having a particle size of 10 μm or less by the centrifugal separation action of the first cyclone 17. Is accumulated at the bottom of the first cyclone 17, and fly ash having a medium particle size and a small particle size of 10 μm or less is conveyed from the top of the first cyclone 17 to the second cyclone 18.

  The large particle size fly ash accumulated in the first cyclone 17 has a small amount of unreacted slaked lime, and is discarded to the fly ash treatment facility via the rotary valve 17a. The separation limit particle diameter of the second cyclone 18 is set to 4 μm. Therefore, the medium and small particle size fly ash conveyed to the second cyclone 18 has a medium particle size fly ash of 4 to 10 μm and a small particle size of less than 4 μm due to the centrifugal separation action of the second cyclone 18. Separated into fly ash, fly ash with a medium particle size of 4 to 10 μm is accumulated at the bottom of the second cyclone 18, and fly ash with a small particle size of less than 4 μm is conveyed from the top of the second cyclone 18 to the mini bag filter 19. Is done. The medium sized fly ash accumulated at the bottom of the second cyclone 18 is slaked lime-rich fly ash and is supplied to the surface polishing machine 4 through the rotary valve 18a. The surface polishing machine 4 is composed of a vibration mill, and performs an operation of rubbing the fly ash particles or the fly ash particles with a steel ball to generate a shearing force on the surface of the particles, thereby performing the surface polishing of the fly ash.

In this way, fly ash surface polishing is performed by the surface polishing machine 4 made of a vibration mill to remove reaction products such as CaCl ₂ adhering to unreacted slaked lime. The fly ash after surface polishing is discharged to the hopper 21. A fixed amount feeder 22 is installed at the bottom of the hopper 21, and the fly ash in the hopper 21 is quantitatively discharged by the constant amount feeder 22. The discharge flow path of the blower 15 is branched in two directions: a flow path toward the first cyclone 17 and a flow path toward the quantitative feeder 22. Air flow regulating valves 25 and 26 are provided at the branch portion. Therefore, the fly ash quantitatively discharged by the quantitative feeder 22 is conveyed to the third cyclone 20 by the airflow sent from the blower 15. The separation limit particle size of the third cyclone 20 is set to 4 μm, and the centrifugal action of the third cyclone 20 collects the fly ash having a medium particle size of 4 to 10 μm, so that Temporary storage at the bottom of the 3 cyclone 20. A small amount of small particle fly ash that could not be separated by the first and second cyclones is conveyed from the upper part of the third cyclone 20 to the mini bag filter 19. Since the fly ash having a medium particle size accumulated at the bottom of the third cyclone 20 is slaked lime-rich fly ash, it is returned to the exhaust gas introduction unit 1 before the bag filter 3 through the rotary valve 20a. The fly ash having a small particle size captured by the mini bag filter 19 is a reaction product rich fly ash containing a large amount of reaction products such as CaCl ₂ , which causes clogging of the filter cloth of the bag filter 3. It is discarded to the fly ash treatment facility via the rotary valve 19a.

  In the second embodiment shown in FIG. 5, the fly ash having a large particle size in the fly ash captured by the bag filter 3 is removed by the first cyclone 17, and the slaked lime rich fly ash is selected. By polishing the surface of the ash, the processing capability of the surface polishing machine 4 can be reduced, and the cost of the surface polishing machine 4 can be reduced. When the fly ash is soft, if the entire surface of the fly ash discharged from the bag filter 3 is guided to the surface polishing machine 4 as in the first embodiment shown in FIG. Ingredients other than slaked lime may be mixed in and the slaked lime concentration may decrease. When the fly ash having the reduced slaked lime concentration is returned to the exhaust gas introduction unit 1, the fly ash is returned unnecessarily, and fly ash that does not contribute to the reaction may circulate. As in the second embodiment shown in FIG. 5, prior to the surface polishing step, the fly ash discharged from the bag filter 3 is classified to remove the large particle size fly ash, thereby eliminating this concern. The

In the said embodiment, although the example which comprised the classification apparatus 5 by the multistage cyclone was demonstrated, you may comprise the classification apparatus 5 with the dry-type fine powder classifier and centrifugal force classifier using the Coanda effect.
The dry fine powder classifier is a device that classifies powder using the Coanda effect. It has three or more classification points, and it is suitable for large ash, medium sized fly ash, and small sized fly ash. Classification is possible with one device.
Centrifugal force classifiers are centrifugal force classifiers that classify powder by injecting fly ash on the wind into the centrifugal force field created by the rotation of the classifying blades. There is an advantage that the point can be adjusted.

  In the above-described embodiment, an example in which special slaked lime is used as the exhaust gas treatment chemical has been described. However, other exhaust gas treatment chemicals such as multiple layers and highly reactive slaked lime can also be used.

  Although the embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention may be implemented in various different forms within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 1 Exhaust gas introduction part 2 Slaked lime supply part 3 Bag filter 4 Surface grinder 5 Classifier 11 Screw feeder 12 Rotary valve 13 Hopper 14,22 Fixed supply machine 15 Blower 17 1st cyclone 17a Rotary valve 18 2nd cyclone 18a Rotary valve 19 Mini bag filter 20 3rd cyclone 20a Rotary valve 21 Hopper 23 Heater 25, 26 Air flow adjustment valve

Claims (12)

Exhaust gas that collects flue gas in exhaust gas by adding exhaust gas treatment chemicals made of powder to exhaust gas discharged from waste incineration facilities and removing acid gas in exhaust gas after passing through a bag filter A processing method,
The fly ash collected by the bag filter is guided to a surface polishing machine for surface polishing, and the fly ash after surface polishing is guided to a classifier to classify the fly ash having a predetermined particle size into other fly ash particles. and, to return the fly ash of the predetermined particle size to exhaust gas upstream of the bag filter,
The surface polishing machine accommodates fly ash and polishing medium in a container-shaped drum, vibrates the drum, and rubs the fly ash particles or the fly ash particles with the polishing medium to polish the fly ash surface. Consists of a vibration mill to perform,
The exhaust gas treatment method according to claim 1, wherein the classifier comprises a cyclone having a rotary valve at a lower portion .   The exhaust gas treatment method according to claim 1, wherein the fly ash having a predetermined particle diameter is fly ash having an average particle diameter of 4 μm to 10 μm.   The exhaust gas treatment method according to claim 1 or 2, wherein the exhaust gas treatment chemical is slaked lime. The cyclone comprises a plurality stages of cyclones, among the plurality of stages of cyclones, separating limit particle diameter of the first-stage cyclone, an exhaust gas processing method according to claim 1, wherein it is set to 10 [mu] m. It said plurality of stages of cyclones, separating limit particle diameter of the second stage cyclone, an exhaust gas processing method according to claim 4, wherein it is set to 4 [mu] m.   2. The exhaust gas treatment method according to claim 1, wherein the fly ash flow path for conveying the fly ash after surface polishing by the surface polishing machine is heated and kept warm. Exhaust gas that collects flue gas in exhaust gas by adding exhaust gas treatment chemicals made of powder to exhaust gas discharged from waste incineration facilities and removing acid gas in exhaust gas after passing through a bag filter A processing device comprising:
A surface polishing machine for polishing the fly ash collected by the bag filter;
A classifying device for classifying the fly ash that has been surface-polished by the surface polishing machine into a fly ash having a predetermined particle size and a fly ash having another particle size;
A fly ash return unit for returning fly ash having a predetermined particle size classified by the classifier to the exhaust gas upstream of the bag filter ;
The surface polishing machine accommodates fly ash and polishing medium in a container-shaped drum, vibrates the drum, and rubs the fly ash particles or the fly ash particles with the polishing medium to polish the surface of the fly ash. Consists of a vibration mill to perform,
The classification device is composed of a cyclone provided with a rotary valve at a lower portion thereof. The exhaust gas treatment apparatus according to claim 7, wherein the fly ash having a predetermined particle diameter is fly ash having an average particle diameter of 4 μm to 10 μm. The exhaust gas treatment apparatus according to claim 7 or 8 , wherein the exhaust gas treatment chemical is slaked lime. The exhaust gas treatment apparatus according to claim 7 , wherein the cyclone includes a plurality of cyclones, and a separation limit particle diameter of the first cyclone among the plurality of cyclones is set to 10 µm. 11. The exhaust gas treatment apparatus according to claim 10, wherein among the plurality of cyclones, a separation limit particle diameter of a second cyclone is set to 4 μm.   The exhaust gas treatment apparatus according to claim 7, wherein the fly ash flow path for conveying fly ash after being surface-polished by the surface polishing machine is heated and kept warm.

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