Cement burning facility and exhaust gas processing method

Abstract

To provide a cement burning facility and an exhaust gas processing method, capable of ensuring stable operation of a cement burning system without increasing heat loss from the cement burning system, without requiring large or complex facilities, and capable of recovering and effectively utilizing a sulfur oxide contained in exhaust gas discharged from a chlorine-containing dust recovery facility.SOLUTION: A cement burning facility includes: a suspension preheater; a rotary kiln; an air quenching cooler; a chlorine-containing dust recovery facility for recovering chlorine-containing dust from exhaust gas-1 extracted from between the cyclone dust collector at a lowest stage of the suspension preheater and the rotary kiln; an exhaust gas-cleaning facility for recovering a sulfur oxide from exhaust gas-2 discharged from the chlorine-containing dust recovery facility; a washing water treatment facility that mixes washing water containing the sulfur oxide discharged from the exhaust gas cleaning facility with the chlorine-containing dust; and an exhaust gas treatment facility that has a supply line for supplying the mixed liquid obtained from the washing water treatment facility to the air quenching cooler.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to cement firing equipment and an exhaust gas treatment method.

Background Art

[0002] Conventionally, for the treatment of chlorine that causes problems such as blockage of a preheater in cement manufacturing equipment, a chlorine bypass system is generally adopted. This system extracts a part of the combustion gas from the kiln exhaust gas flow path from the kiln end of the cement kiln to the lowermost cyclone of the preheater in the cement kiln equipment, removes chlorine from the extracted gas, and removes chlorine present in the cement kiln system to the outside of the system.

[0003] Chlorine contained in the extracted gas exists in the gas phase and the liquid phase, and transfers to the solid phase by condensation due to cooling or the like. This is a system that recovers it as a powder containing a chlorine component by solid-gas separation. The gas discharged from the above chlorine bypass system (hereinafter referred to as "chlorine bypass exhaust gas") contains high-concentration sulfur oxides (SO 2 etc.), and these are treated in a cement firing system such as a preheater. However, treating the chlorine bypass exhaust gas in the cement firing system causes problems such as an increase in the heat loss of the system and a decrease in the clinker production amount, as well as causing coating troubles due to the concentration of sulfur oxides.

[0004] To address such problems, technologies for desulfurizing chlorine bypass exhaust gas have been developed. For example, Patent Document 1 discloses a treatment device for chlorine bypass exhaust gas including a desulfurization tower that contacts a slurry composed of the recovered chlorine bypass dust with the chlorine bypass exhaust gas to perform desulfurization. Further, Patent Document 2 discloses a treatment device for chlorine bypass exhaust gas including a dry desulfurization device at the subsequent stage of the chlorine bypass system.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The method for treating chlorine bypass exhaust gas (wet method) described in Patent Document 1 requires, in addition to large-scale dedicated equipment, equipment for treating wastewater and sludge generated during the treatment of exhaust gas. Also, in the method for treating chlorine bypass exhaust gas (dry method) described in Patent Document 2, large-scale dedicated equipment is required in the same manner as the above wet method. In these treatment methods, since the treatment equipment becomes large-scale and the process design becomes complicated, it has been difficult to install the above equipment as exhaust gas treatment equipment.

[0007] The present invention has been made in view of such circumstances, and without requiring large-scale equipment or complicated equipment, it ensures the stable operation of the cement firing system without increasing the heat loss of the cement firing system, and also recovers and effectively utilizes sulfur oxides contained in the exhaust gas discharged from the chlorine-containing dust recovery equipment. An object of the present invention is to provide a cement firing facility and an exhaust gas treatment method.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following invention.

[0009] That is, the present invention relates to the following. [1] A suspension preheater, A rotary kiln, An air quenching cooler, A chlorine-containing dust recovery facility that recovers chlorine-containing dust from exhaust gas-1 extracted from between the cyclone dust collector at the lowermost stage of the suspension preheater and the rotary kiln, An exhaust gas treatment facility including an exhaust gas scrubbing facility for recovering sulfur oxides from exhaust gas - 2 discharged from the chlorine - containing dust recovery facility, a washing water treatment facility for mixing washing water containing sulfur oxides discharged from the exhaust gas scrubbing facility with the chlorine - containing dust, and a supply line for supplying the mixed liquid obtained in the washing water treatment facility to the air quenching cooler, and a cement firing facility including the same. [2] The cement firing facility according to [1] above, wherein the exhaust gas scrubbing facility includes a sprayer for spraying water onto the exhaust gas - 2, a scrubbing device, and an exhaust fan for exhausting exhaust gas - 3 discharged from the scrubbing device. [3] The cement firing facility according to [2] above, wherein the exhaust gas scrubbing facility includes a wet scrubber composed of the sprayer and the scrubbing device. [4] The cement firing facility according to any one of [1] to [3] above, wherein the washing water treatment facility includes a reaction tank for mixing the washing water containing sulfur oxides with the chlorine - containing dust, a storage tank for storing the mixed liquid of the washing water containing sulfur oxides and the chlorine - containing dust, and a pressure pump for pressurizing the mixed liquid. [5] A suspension preheater, a rotary kiln, an air quenching cooler, a chlorine - containing dust recovery facility for recovering chlorine - containing dust from exhaust gas - 1 extracted between the cyclone dust collector at the lowermost stage of the suspension preheater and the rotary kiln, In a cement firing facility including an exhaust gas scrubbing facility for recovering sulfur oxides from exhaust gas - 2 discharged from the chlorine - containing dust recovery facility, a washing water treatment facility for mixing washing water containing sulfur oxides discharged from the exhaust gas scrubbing facility with the chlorine - containing dust, and a supply line for supplying the mixed liquid obtained in the washing water treatment facility to the air quenching cooler, An exhaust gas treatment method in which the mixed liquid is supplied to the clinker in the air quenching cooler by the exhaust gas treatment facility. [6] The exhaust gas - 2 contains sulfur oxides, and water is brought into contact with the exhaust gas - 2 to obtain an aqueous solution containing sulfur oxides, the exhaust gas treatment method according to [5] above. [7] The mixed solution has a pH at 25°C of 5 or more and less than 12, the exhaust gas treatment method according to [5] or [6] above. [8] In the washing water treatment facility, gypsum is formed from the washing water containing sulfur oxides and the chlorine - containing dust, the exhaust gas treatment method according to any one of [5] to [7] above. [9] The ambient temperature when the mixed solution is supplied to the clinker in the air quenching cooler is less than 300°C, the exhaust gas treatment method according to any one of [5] to [8] above.

[10] The supply amount of the mixed solution supplied to the clinker is 15 to 100 kg per ton of clinker, the exhaust gas treatment method according to any one of [5] to [9] above.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a cement firing facility and an exhaust gas treatment method that do not require large - scale equipment or complex equipment, ensure the stable operation of the cement firing system without increasing the heat loss of the cement firing system, recover and effectively utilize sulfur oxides contained in the exhaust gas discharged from the chlorine - containing dust recovery facility.

Brief Description of the Drawings

[0011]

Figure 1

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention (hereinafter sometimes referred to as "the present embodiment") will be described. The present invention is not limited to the following embodiments and can be arbitrarily modified and implemented within a range that does not inhibit the effects of the invention. In the present specification, the numerical range notation of "AA to BB" means "AA or more and BB or less". Also, in the present specification, the numerical values related to "or more", "or less" and "to" in the description of numerical ranges are numerical values that can be arbitrarily combined. For example, when a certain numerical range is described as "CC to DD" and "EE to FF", numerical ranges such as "CC to FF" and "EE to DD" are also included.

[0013] [Cement firing equipment] The cement firing equipment of the present embodiment is a suspension preheater, a rotary kiln, an air quenching cooler, a chlorine-containing dust recovery facility that recovers chlorine-containing dust from exhaust gas-1 extracted from between the cyclone dust collector at the lowermost stage of the suspension preheater and the rotary kiln, an exhaust gas cleaning facility that recovers sulfur oxides from exhaust gas-2 discharged from the chlorine-containing dust recovery facility, washing water containing sulfur oxides discharged from the exhaust gas cleaning facility, a washing water treatment facility that mixes the washing water and the chlorine-containing dust, and an exhaust gas treatment facility having a supply line that supplies the mixed liquid obtained in the washing water treatment facility to the air quenching cooler.

[0014] The cement firing facility of this embodiment is equipped with an exhaust gas treatment facility having specific exhaust gas cleaning equipment, washing water treatment equipment, and supply lines, and thus does not require large-scale and complex equipment such as those in References 1 and 2. Further, since the exhaust gas - 2 discharged from the chlorine-containing dust recovery facility is not reused by a suspension preheater as in the prior art, stable operation of the cement firing system can be ensured without increasing the heat loss of the cement firing system. Furthermore, by providing the exhaust gas treatment facility in this embodiment, sulfur oxides contained in the exhaust gas - 2 can be recovered and effectively utilized.

[0015] Hereinafter, the cement firing facility of this embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing a preferred embodiment of the cement firing facility of this embodiment. FIG. 1 shows that the cement firing facility 20 of this embodiment includes a suspension preheater 1, a rotary kiln 2, and an air quenching cooler 3, also includes a chlorine-containing dust recovery facility 4, and further includes an exhaust gas treatment facility 10 having an exhaust gas cleaning equipment 5, a washing water treatment equipment 6, and a supply line 7.

[0016] The cement firing facility 20 of this embodiment includes devices used in general cement firing facilities, that is, a suspension preheater 1, a rotary kiln 2, and an air quenching cooler 3. These devices can use conventionally used devices. Also, cement raw materials can be used without limitation those conventionally used.

[0017] Cement raw materials are fed into the suspension preheater 1, and the cement raw materials preheated and calcined in the suspension preheater 1 are conveyed to the rotary kiln 2, where they are fired to produce clinker. The produced clinker is conveyed to the air quenching cooler 3 and cooled. Here, the ambient temperature in the air quenching cooler 3 decreases as it approaches the discharge port where the clinker is discharged. As a specific example, in the air quenching cooler 3, the ambient temperature near the supply port where the clinker is supplied is in the range of 600 to 1000 °C, and the ambient temperature near the discharge port where the clinker is discharged is in the range of 150 to 300 °C. The above cement raw materials may be dried and pulverized by a cement raw material drying and pulverizing machine (not shown) and then fed into the suspension preheater 1. Note that a conventionally used device can be used as the cement raw material drying and pulverizing machine.

[0018] 〔Chlorine-containing dust recovery facility〕 The chlorine-containing dust recovery facility 4 is a facility for recovering chlorine-containing dust from the exhaust gas -1 extracted between the cyclone dust collector at the lowermost stage of the suspension preheater 1 and the rotary kiln 2. Since the gases in the cyclone dust collector and the rotary kiln 2 are both at a high temperature of 1000 to 1100 °C, the exhaust gas -1 extracted from the gas is cooled to about 200 °C by a cooler and then supplied to the chlorine-containing dust recovery facility 4. In this specification, the "cyclone dust collector at the lowermost stage" refers to the cyclone dust collector that supplies the powder raw material to the rotary kiln 2. Also, the "chlorine-containing dust" refers to particulate matter containing chlorine contained in the exhaust gas -1 extracted between the cyclone dust collector at the lowermost stage of the suspension preheater 1 and the rotary kiln 2. The chlorine-containing dust contains calcium oxide and the like in addition to chlorine.

[0019] The chlorine-containing dust recovery facility 4 preferably includes a classifier for separating chlorine-containing dust in the exhaust gas -1. Examples of the classifier include a cyclone, a bag filter, etc. These may be used alone or in combination of two or more. The exhaust gas -1 is separated by the classifier into exhaust gas -2 containing chlorine-containing dust and sulfur oxides. The separated chlorine-containing dust is stored in a storage tank and supplied to a washing water treatment facility 6 described later. Further, the exhaust gas -2 is supplied to an exhaust gas washing facility 5 by an exhaust fan (not shown). In a conventional chlorine bypass facility, it was common for the exhaust gas after dust collection by a dust collector such as a bag filter to be returned to the gas flow path in the suspension preheater. In the cement firing facility of the present embodiment, the exhaust gas passing through the dust collector is supplied to an exhaust gas treatment facility, and the exhaust gas that has undergone treatment is discharged outside the system through a chimney. Thereby, while reducing heat loss, reduction of sulfur circulation is also achieved, and it becomes possible to prevent adhesion and blockage by sulfur oxides.

[0020] 〔Exhaust Gas Treatment Facility〕 The exhaust gas treatment facility 10 in the present embodiment includes an exhaust gas washing facility 5 for recovering sulfur oxides from the exhaust gas -2 discharged from the chlorine-containing dust recovery facility 4, washing water containing sulfur oxides discharged from the exhaust gas washing facility 5, a washing water treatment facility 6 for mixing the washing water with the chlorine-containing dust, and a supply line 7 for supplying the mixed liquid obtained in the washing water treatment facility 6 to the air quenching cooler 3.

[0021] (Exhaust Gas Washing Facility) The exhaust gas washing facility 5 is a facility for recovering sulfur oxides from the exhaust gas -2 discharged from the chlorine-containing dust recovery facility 4. The exhaust gas washing facility 5 is not particularly limited as long as it can recover sulfur oxides from the exhaust gas -2, but preferably includes a sprayer for spraying water into the exhaust gas -2, a washing device, and an exhaust fan for exhausting the exhaust gas -3 discharged from the washing device. The method of spraying water into the exhaust gas - 2 is not particularly limited. For example, a method of inserting the nozzle of a sprayer into the pipe connecting the chlorine - containing dust recovery facility 4 and the scrubber can be mentioned.

[0022] Moreover, from the viewpoint of further enhancing the recovery of sulfur oxides, it is preferable that the exhaust gas scrubbing facility 5 includes a wet scrubber composed of the above - mentioned sprayer and the above - mentioned scrubber. The wet scrubber can separate the exhaust gas - 2 into scrubbing water (aqueous solution) containing sulfur oxides and exhaust gas - 3 from which sulfur oxides have been removed by bringing the exhaust gas - 2 into contact with water. Examples of the wet scrubber include those having a form in which a sprayer is provided at the upper part of a vessel (tank), exhaust gas - 2 is supplied from the lower part of the vessel, and the exhaust gas - 2 can be brought into contact with the water sprayed from the upper - part sprayer. Moreover, as the method of the wet scrubber, there are a method of injecting pressurized scrubbing water into the flow of exhaust gas - 2 (pressurized water type), a method of allowing exhaust gas - 2 to pass through standing water (standing water type), a method of dispersing scrubbing water with a rotating body and bringing it into contact with exhaust gas - 2 (rotating type), etc.

[0023] The supply of water to the exhaust gas - 2 is preferably supplied so that the gas temperature exhausted from the exhaust gas scrubbing facility 5 is 20 - 80°C, more preferably 30 - 60°C, and even more preferably 35 - 55°C. When the gas temperature passing through the exhaust gas scrubbing facility 5 is within the above range, sulfur oxides can be efficiently recovered.

[0024] After scrubbing by the wet scrubber, the exhaust gas - 3 (including carbon dioxide and water vapor) has less sulfur oxides than the exhaust gas - 2, so it can be exhausted from the exhaust gas scrubbing facility 5 by an exhaust fan and discharged from the chimney 8.

[0025] (Scrubbing water treatment facility) The scrubbing water treatment facility 6 is a facility for mixing the scrubbing water containing sulfur oxides discharged from the above - mentioned exhaust gas scrubbing facility 5 and the chlorine - containing dust recovered by the above - mentioned chlorine - containing dust recovery facility 4. The washing water treatment equipment 6 is not particularly limited, but preferably includes a reaction tank for mixing the washing water containing the sulfur oxide and the chlorine-containing dust, a storage tank for storing the mixed liquid of the washing water containing the sulfur oxide and the chlorine-containing dust, and a pressure pump for pressurizing the mixed liquid.

[0026] As the reaction tank, known ones can be used, and any type such as a vertical stirring complete mixing tank, a vertical heat convection mixing tank, a tower type continuous reaction tank, etc. may be used. Also, it may be a single tank or a plurality of tanks of the same or different types connected in series or in parallel. Among them, a reaction tank having a stirring device is preferable. As the stirring device, in addition to the normal type consisting of a power unit, a bearing, a shaft, and a stirring blade, high-speed rotating types such as a turbine stator type high-speed rotating stirrer, a disk mill type stirrer, and a rotor mill type stirrer can also be used. Further, the reaction tank may be used in combination with the storage tank, but considering the ease of operation of the equipment, it is preferable to provide a storage tank separately from the reaction tank.

[0027] The form of stirring is not particularly limited. In addition to the normal stirring method of directly stirring the reaction liquid in the reaction tank from the upper part, lower part, side part, etc. of the reaction tank, a method of taking out a part of the reaction liquid outside the reactor with a pipe or the like and stirring it with a line mixer or the like and circulating the reaction liquid can also be adopted.

[0028] The type of the stirring blade can be selected from known ones. Specifically, propeller blades, screw blades, turbine blades, fan turbine blades, disk turbine blades, Faudler blades, full zone blades, max blend blades, etc. can be mentioned.

[0029] After the washing water containing sulfur oxide is supplied to the reaction tank from the washing device and the chlorine-containing dust is supplied from the storage tank of the chlorine-containing dust recovery equipment 4, by stirring and mixing, gypsum is formed by the reaction between the sulfur oxide contained in the washing water and the calcium oxide contained in the chlorine-containing dust, and a mixed liquid containing this is obtained. The mixed liquid may contain sulfur oxide not used in the reaction. The obtained mixed liquid is stored in the storage tank.

[0030] The mixing ratio of the above-mentioned washing water and the above-mentioned chlorine-containing dust is preferably 2:1 to 25:1, more preferably 5:1 to 25:1, and even more preferably 10:1 to 25:1 in terms of mass ratio [washing water: chlorine-containing dust]. When the mixing ratio of the washing water and the chlorine-containing dust is within the above range, gypsum can be efficiently formed.

[0031] (Supply line) The supply line 7 included in the exhaust gas treatment facility 10 in the present embodiment connects the above-mentioned washing water treatment facility 6 and the air quenching cooler 3. The mixed liquid in the storage tank included in the above-mentioned washing water treatment facility 6 is pressurized by a pressure pump and supplied to the air quenching cooler 3 through the above-mentioned supply line 7. By supplying the mixed liquid to the air quenching cooler 3, it becomes possible to remove the moisture in the mixed liquid and recover the gypsum in the mixed liquid together with the clinker.

[0032] [Exhaust gas treatment method] The exhaust gas treatment method of the present embodiment is a suspension preheater, a rotary kiln, an air quenching cooler, a chlorine-containing dust recovery facility for recovering chlorine-containing dust from the exhaust gas-1 extracted from between the cyclone dust collector at the lowermost stage of the suspension preheater and the rotary kiln, an exhaust gas washing facility for recovering sulfur oxides from the exhaust gas-2 discharged from the chlorine-containing dust recovery facility, a washing water treatment facility for mixing the washing water containing sulfur oxides discharged from the exhaust gas washing facility and the chlorine-containing dust, and an exhaust gas treatment facility having a supply line for supplying the mixed liquid obtained in the washing water treatment facility to the air quenching cooler, in a cement firing facility wherein the exhaust gas treatment facility supplies the mixed liquid to the clinker in the air quenching cooler.

[0033] In the cement firing facility of the present embodiment, the mixed liquid obtained in the washing water treatment facility 6 is preferably stored in a storage tank once, and then supplied to the clinker in the air quenching cooler 3 through a supply line 7 connecting the storage tank and the air quenching cooler 3. By injecting the above mixed liquid into the air quenching cooler 3, the moisture in the mixed liquid can be removed, and the gypsum in the mixed liquid can be recovered together with the clinker. Further, sulfur oxides contained in the mixed liquid may react with calcium oxide in the clinker dust in the air quenching cooler to form gypsum. According to the exhaust gas treatment method of the present embodiment, sulfur oxides contained in the exhaust gas - 2 discharged from the chlorine - containing dust recovery facility 4 can be recovered and effectively utilized as gypsum for cement raw materials.

[0034] The pH of the above mixed liquid at 25°C is preferably 5 or more and less than 12, more preferably 7 or more and 10 or less, and still more preferably 7 or more and 9 or less. The chlorine - containing dust recovered by the chlorine - containing dust recovery facility exhibits strong alkalinity, and the washing water containing sulfur oxides exhibits strong acidity. Therefore, by mixing them, mild conditions near neutrality are achieved, and the pH of the resulting mixed liquid at 25°C can be within the above range. Therefore, the materials and the like in the washing water treatment facility 6 can be made less expensive, and the equipment load can be reduced.

[0035] The ambient temperature when supplying the above mixed liquid to the clinker in the air quenching cooler 3 is preferably less than 300°C, more preferably 250°C or less, and still more preferably 200°C or less. When the above temperature is less than 300°C, the vaporization of sulfur oxides contained in the mixed liquid can be suppressed.

[0036] The supply amount of the above mixed liquid supplied to the above clinker is preferably 15 - 100 kg per ton of clinker, more preferably 15 - 75 kg, and still more preferably 15 - 50 kg. When the supply amount of the mixed liquid is 15 kg or more, the amount of gypsum used in the finishing process of cement can be reduced.

Example

[0037] Next, the present invention will be specifically described by way of examples. However, the present invention is not limited by these examples in any way.

[0038] (Example 1) In the cement firing facility 20 shown in FIG. 1, 1000 kg of washing water containing sulfur oxides obtained from the exhaust gas washing facility 5 and 50 kg of chlorine-containing dust obtained from the chlorine-containing dust recovery facility 4 were put into a reactor equipped with a stirrer and stirred and mixed to obtain a mixed solution. When 50 kg of the obtained mixed solution was supplied per ton of clinker, it became possible to supply gypsum corresponding to 2.0 kg per ton of cement, and it became possible to reduce the supply amount of gypsum that had been separately supplied in the finishing process until now.

[0039] (Comparative Example 1) When the same procedure as in Example 1 was carried out except that the mixed solution was not supplied in Example 1, it was necessary to use about 30.0 kg of gypsum per ton of cement in the finishing process.

Explanation of Signs

[0040] 1 Suspension preheater 2 Rotary kiln 3 Air quenching cooler 4 Chlorine-containing dust recovery facility 5 Exhaust gas washing facility 6 Washing water treatment facility 7 Supply line 8 Chimney 10 Exhaust gas treatment facility 20 Cement firing facility

Claims

1. A suspension preheater, a rotary kiln, an air quenching cooler, chlorine-containing dust recovery equipment for recovering chlorine-containing dust from exhaust gas-1 extracted from between the cyclone dust collector at the lowermost stage of the suspension preheater and the rotary kiln, exhaust gas cleaning equipment for recovering sulfur oxides from exhaust gas-2 discharged from the chlorine-containing dust recovery equipment, washing water containing sulfur oxides discharged from the exhaust gas cleaning equipment, washing water treatment equipment for mixing the washing water and the chlorine-containing dust, and exhaust gas treatment equipment having a supply line for supplying the mixed liquid obtained by the washing water treatment equipment to the air quenching cooler, a cement firing facility comprising.

2. The exhaust gas cleaning equipment includes a sprayer for spraying water on the exhaust gas-2, a cleaning device, and an exhaust fan for exhausting exhaust gas-3 discharged from the cleaning device. The cement firing facility according to claim 1.

3. The exhaust gas cleaning equipment includes a wet scrubber constituted by the sprayer and the cleaning device. The cement firing facility according to claim 2.

4. The washing water treatment equipment includes a reaction tank for mixing the washing water containing sulfur oxides and the chlorine-containing dust, a storage tank for storing the mixed liquid of the washing water containing sulfur oxides and the chlorine-containing dust, and a pressure pump for pressurizing the mixed liquid. The cement firing facility according to claim 1.

5. A suspension preheater, a rotary kiln, an air quenching cooler, chlorine-containing dust recovery equipment for recovering chlorine-containing dust from exhaust gas-1 extracted from between the cyclone dust collector at the lowermost stage of the suspension preheater and the rotary kiln, exhaust gas cleaning equipment for recovering sulfur oxides from exhaust gas-2 discharged from the chlorine-containing dust recovery equipment, washing water containing sulfur oxides discharged from the exhaust gas cleaning equipment, washing water treatment equipment for mixing the washing water and the chlorine-containing dust, and exhaust gas treatment equipment having a supply line for supplying the mixed liquid obtained by the washing water treatment equipment to the air quenching cooler, in a cement firing facility comprising. An exhaust gas treatment method in which the mixed liquid is supplied to clinker in the air quenching cooler by the exhaust gas treatment equipment.

6. The exhaust gas-2 contains sulfur oxides, and the exhaust gas-2 is brought into contact with water to obtain an aqueous solution containing sulfur oxides. The exhaust gas treatment method according to claim 5.

7. The exhaust gas treatment method according to claim 5, wherein the mixed solution has a pH at 25°C of 5 or more and less than 12.

8. The exhaust gas treatment method according to claim 5, wherein in the washing water treatment facility, gypsum is formed from the washing water containing sulfur oxides and the chlorine-containing dust.

9. The exhaust gas treatment method according to claim 5, wherein the ambient temperature when the mixed solution is supplied to the clinker in the air quenching cooler is less than 300°C.

10. The exhaust gas treatment method according to claim 5, wherein the supply amount of the mixed solution supplied to the clinker is 15 to 100 kg per ton of the clinker.

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