Cooling device and cooling method for white cement clinker

Abstract

[Problem] To efficiently recover heat from high-temperature white cement clinker. [Solution] A cooling device 1 for white cement clinker, said cooling device 1 comprising: a clinker conveyance device 5 which is for adding cooled white cement clinker to high-temperature white cement clinker C1 present at an outlet of a cement kiln 2 and mixing and cooling the high-temperature white cement clinker C1 in the cement kiln 2; and a water spraying device 6 which sprays water onto the white cement clinker C1 present at the outlet of the cement kiln 2. The clinker conveyance device 5 can convey, to the outlet of the cement kiln 2, white cement clinker C3 (C5) immediately after discharge from a clinker cooler 3 provided to the cement kiln 2.

Description

Cooling device and cooling method for white cement clinker

[0001] The present invention relates to a cooling device and method for white cement clinker, and more particularly to a device and method for efficiently recovering heat while maintaining whiteness when cooling high-temperature white cement clinker.

[0002] Conventionally, in order to maintain the whiteness of cement powder, white cement has been produced by cooling high-temperature cement clinker C1 discharged from a cement kiln (hereinafter referred to as the "kiln") 2 in an oxygen-blocked atmosphere to prevent oxidation of the iron and other components contained in the clinker C1, as shown in FIG. 2. The mainstream method involves using a sprinkler device 6 to sprinkle water on the clinker C1 present at the kiln outlet, transporting the sprinkled clinker C2 in a clinker cooler (hereinafter referred to as the "cooler") 3 while cooling it with air A1 from a blower 4, and discharging the cooled clinker C3.

[0003] However, in the above-mentioned conventional method, the gas generated in the cooler 3 is mostly water vapor with little oxygen and is low in temperature, so it cannot be introduced into the kiln 2 as secondary air and must be discharged from the cooler 3 as exhaust gas A4, which poses the problem of not being able to recover heat.

[0004] Therefore, an object of the present invention is to provide a cooling device and a cooling method that can efficiently recover heat from high-temperature white cement clinker.

[0005] In order to achieve the above object, the present invention provides a cooling device for white cement clinker, which is characterized by comprising a clinker transport device for adding cooled white cement clinker to high-temperature white cement clinker present at a kiln outlet and mixing and cooling the high-temperature white cement clinker within the kiln, and a sprinkler device for sprinkling water on the white cement clinker present at the kiln outlet.

[0006] According to the present invention, cooled white cement clinker is added to the hot white cement clinker present at the kiln outlet and water is sprayed on it to convert the iron in the clinker into white Fe. ３ O ４After lowering the temperature to a temperature range where it can be stabilized, it is cooled in a cooler (air quenching cooler), which makes it possible to effectively use the air that has exchanged heat with the clinker as combustion air (secondary air, tertiary air).

[0007] In the cooling system, the clinker transport device can transport the white cement clinker to the kiln outlet immediately after it is discharged from a cooler attached to the kiln. The cooled clinker can be extracted from a clinker silo or the like, but it is more efficient to separate the clinker at the cooler outlet, which has a shorter transport distance.

[0008] In the cooling device, the gas recovered from the cooler after cooling the clinker can be effectively utilized by being directly supplied to the kiln as an oxygen source for combustion.

[0009] The present invention also provides a method for cooling white cement clinker, which comprises adding cooled white cement clinker to high-temperature white cement clinker present at a kiln outlet, mixing and cooling the high-temperature white cement clinker in a kiln, and spraying water onto the white cement clinker present at the kiln outlet.

[0010] According to the present invention, cooled white cement clinker is added to the hot white cement clinker present at the kiln outlet and water is sprayed on it to convert the iron in the clinker into white Fe. ３ O ４ After lowering the temperature to a temperature range where it can be stabilized, it is cooled in a cooler (air quenching cooler), which makes it possible to effectively use the air that has exchanged heat with the clinker as combustion air (secondary air, tertiary air).

[0011] In the above cooling method, the white cement clinker to be added to the high-temperature white cement clinker present at the kiln outlet can be white cement clinker immediately after being discharged from a cooler attached to the kiln. The cooled clinker can be extracted from a clinker silo or the like, but it is more efficient to separate the clinker at the cooler outlet, which has a short transport distance.

[0012] In the above cooling method, the gas recovered from the cooler after cooling the clinker can be effectively utilized by being directly supplied to the kiln as an oxygen source for combustion.

[0013] By adding 50% by mass or more of the cooled white cement clinker to the high-temperature white cement clinker present at the cement kiln outlet, the temperature of the cement clinker after water sprinkling can be controlled to 500°C or higher and 600°C or lower, and by adding 50% by mass or more (preferably 100% by mass to 120% by mass) of the cooled clinker to the high-temperature clinker present at the kiln outlet, it is possible to reduce the amount of water sprinkled to 26% by mass or lower (conventionally 76% or lower) of the amount of high-temperature white cement clinker after burning.

[0014] As described above, according to the present invention, heat can be efficiently recovered from high-temperature white cement clinker.

[0015] The present invention relates to a cooling system for white cement clinker, and a cooling apparatus for white cement clinker according to the present invention.

[0016] Next, an embodiment of the present invention will be described in detail with reference to the drawings.

[0017] FIG. 1 shows one embodiment of a cooling device according to the present invention. This cooling device 1 includes a cooler 3 that cools white cement clinker (hereinafter referred to as "clinker") C1 discharged from a kiln 2 with air A1 from a blower 4, a clinker transport device 5 that transports a portion C5 of the clinker C3 discharged from the cooler 3 to the outlet of the kiln 2, and a sprinkler device 6 that sprinkles water on the clinker C1 present at the outlet of the kiln 2.

[0018] The cooler 3 is, for example, an air quenching type cooler having a plurality of grates with slits formed therein, in which cooling air A1 is blown from the bottom of the grates through the slits by a blower 4, thereby transporting the clinker C2 while cooling it.

[0019] The clinker transport device 5 is composed of a separation device 8 that separates a portion C5 of the clinker C3 discharged from the cooler 3, and a general transport device, and the transport device penetrates the kiln front hood 7 and drops the clinker C5 into the outlet of the kiln 2.

[0020] The sprinkler device 6 has a pipe that passes through the kiln front hood 7 and a plurality of sprinkler nozzles at the end of the pipe on the kiln side, and sprinkles water evenly over the clinker C1 present at the outlet of the kiln 2.

[0021] Next, the operation of the cooling device 1 will be described with reference to FIG.

[0022] During operation of the kiln 2, air A1 is introduced into the cooler 3 from the blower 4, and the clinker C2 discharged from the kiln 2 is cooled by the air A1. At the same time, a portion C5 of the clinker C3 discharged from the cooler 3 is collected and dropped into the outlet of the kiln 2 by a clinker conveying device 5. Since the clinker C3 discharged from the cooler 3 has been cooled to about 120°C, the clinker C1 present at the outlet is cooled. At the same time, the water sprinkler 6 sprays water on the clinker C1 present at the outlet of the kiln 2 to further cool it.

[0023] The reason for cooling the clinker C1 present at the outlet of the kiln 2 by the clinker C5 and water spray is to convert the iron in the clinker C1 into black Fe in order to maintain the whiteness of the cement powder. ２ O ３ White Fe ３ O ４ The clinker is cooled to 500 to 600°C, and the iron in the clinker C1 is converted into white Fe. ３ O ４ Stabilize it with.

[0024] As described above, by cooling the clinker C1 present at the downspout with clinker C5 before water spraying, the amount of water sprayed can be reduced, the amount of steam generated is also reduced, the cooled gas can be extracted at a high temperature, and the clinker C2 cooled in the kiln 2 can maintain its whiteness even when cooled in the cooler 3, so high-temperature secondary air A2 of about 400°C can be supplied to the kiln 2, allowing efficient heat recovery from the high-temperature clinker C1. Furthermore, the tertiary air A3 discharged from the cooler 3 is used in a calciner or the like attached to the kiln 2, as in general cement firing equipment. The clinker C4 discharged from the cooler 3 and not separated is transported to the subsequent cement crushing process.

[0025] In addition to the above effects, by introducing clinker C5 into the outlet of the kiln 2, the clinker layer in the kiln 2 becomes thicker, increasing the amount of heat recovered. Furthermore, a stable, thick layer of clinker can be stably exchanged with the air in the cooler 3, and the clinker is less likely to adhere to each other (the clinker is less likely to become sticky), allowing for stable transport of the clinker within the cooler 3. As a result, the operation of the kiln is also stabilized.

[0026] Table 1 shows the simulation results for the cooling device 1 according to the present embodiment (Examples 1 to 3) and the conventional cooling device (Comparative Example) shown in Fig. 2. In Examples 1 to 3, the addition rate of cooled clinker was changed to 50 mass%, 100 mass%, and 120 mass%.

[0027] From the table, it can be seen that by adding cooled clinker in an amount of 50% by mass or more (preferably 100% by mass to 120% by mass) of the high-temperature clinker present at the outlet of kiln 2, the amount of water sprayed can be reduced to 26% by mass or less (conventional 76% or less) of the amount of high-temperature white cement clinker after burning.

[0028]

[0029] In the above embodiment, the clinker C3 (C5) immediately after being discharged from the cooler 3 is dropped into the outlet of the kiln 2, but it is also possible to use clinker that has been temporarily stored in a storage tank or storage area, rather than clinker immediately after being discharged from the cooler 3. Any white cement clinker that has been cooled to a temperature of about 120°C or less can be used.

[0030] The illustrated embodiments are merely examples and are not intended to limit the technical scope of the present invention.

[0031] REFERENCE SIGNS LIST 1 Cooling device 2 Kiln 3 Cooler 4 Blower 5 Clinker conveying device 6 Sprinkler device 7 Kiln front hood 8 Separation device

Claims

1. A white cement clinker cooling device comprising: a clinker conveying device for adding cooled white cement clinker to high-temperature white cement clinker present at the cement kiln outlet and mixing and cooling the high-temperature white cement clinker within the cement kiln; and a sprinkler device for sprinkling water on the white cement clinker present at the cement kiln outlet.

2. A cooling device for white cement clinker as described in claim 1, characterized in that the clinker transporting device transports white cement clinker to the cement kiln outlet immediately after it is discharged from a clinker cooler attached to the cement kiln.

3. A cooling device for white cement clinker according to claim 1 or 2, characterized in that the gas recovered from the clinker cooler after cooling the clinker is directly supplied into the cement kiln as an oxygen source for combustion.

4. A method for cooling white cement clinker, comprising adding cooled white cement clinker to high-temperature white cement clinker present at a cement kiln outlet, mixing and cooling the high-temperature white cement clinker in the cement kiln, and spraying water onto the white cement clinker present at the cement kiln outlet.

5. A method for cooling white cement clinker according to claim 3, characterized in that the white cement clinker added to the high-temperature white cement clinker present at the cement kiln outlet is white cement clinker immediately after being discharged from a clinker cooler attached to the cement kiln.

6. A method for cooling white cement clinker according to claim 4 or 5, characterized in that the gas recovered from the clinker cooler after cooling the clinker is directly supplied into the cement kiln as an oxygen source for combustion.

7. A method for cooling white cement clinker according to any one of claims 4 to 6, characterized in that the cooled white cement clinker is added in an amount of 50 mass % or more to the high-temperature white cement clinker present at the cement kiln outlet, and the temperature of the cement clinker after water spraying is controlled to be 500°C or more and 600°C or less.

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