JP2001335348A - Cement kiln waste gas bleeding treatment apparatus and its operation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a bleeding structure of a bleeding treatment apparatus where cement kiln exhaust gas is taken out from a kiln inlet hood 2 through a bleeding pipe and the taken out gas is mixed with cooling air to lower its temperature for treatment, and also facilitate adjustment of the apparatus in operation time. SOLUTION: An outlet 3b side end part of the bleeding pipe 3 of the above apparatus is inserted, with a gap 6, into an inside of a tip end part of a suction duct 4 which has a diameter-expanding part gradually expanding toward the tip end. The kiln exhaust gas is taken out from the suction duct 4 through the bleeding pipe 3 by making inside pressure of the suction duct 4 negative, while outer air sucked as cooling air through the gap 6 is introduced into the suction duct 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement kiln with an SP (suspension pre-heater) and an NS.
Used for cement kiln equipment such as cement kiln equipment with P (new suspension preheater), which is generated when firing cement clinker and causes volatile components (alkali chloride or alkali sulfate) The present invention relates to an apparatus for extracting and treating a part of the exhaust gas of a cement kiln in order to reduce the concentration in the equipment, and an operation method thereof. More specifically, the present invention relates to a cement kiln exhaust gas extraction apparatus for extracting exhaust gas from a cement kiln from a kiln inlet hood through an extraction pipe, mixing the extracted exhaust gas with cooling air to reduce the exhaust gas temperature, and an operation method thereof.

[0002]

2. Description of the Related Art Conventionally, a cement kiln exhaust gas extraction apparatus for extracting exhaust gas from a cement kiln from a kiln inlet hood through an extraction pipe and mixing the extracted exhaust gas with cooling air to reduce the exhaust gas temperature and treat the exhaust gas has been known. A cooling chamber and a chamber are sequentially connected to the trachea, and cooling air is sent to the cooling chamber by a fan so as to generate a swirling flow along the inner wall surface from the cooling chamber to the vicinity of the inlet of the bleed pipe, thereby cooling volatile components. In addition to suppressing the contact of the exhaust gas with insufficient solidification with the extraction pipe and the inner wall surface of the cooling chamber with the swirling flow of cooling air,
It is known that the exhaust gas and the cooling air are sent into the chamber while being gradually mixed, and the cooling air and the exhaust gas are mixed in the chamber so that the temperature of the exhaust gas can be reduced to a required temperature (Japanese Patent Laid-Open No. 9-09-1997). No. 175847).

[0003] In addition, the bleeding tube is formed as a double structure with an inner tube and an outer tube, and the end of the outer tube on the kiln inlet hood side is provided with a gradually narrowed narrowed portion, so that the cooling is provided between the inner tube and the outer tube. The cooling air is sent into the swirl by a fan, and the cooling air is guided to the inside of the inner tube at the narrowing portion and mixed with the exhaust gas near the kiln inlet hood side end of the inner tube. A device capable of rapid cooling is also known (JP-A-11-35555).

[0004]

However, all of the above-mentioned conventional cement kiln bleeding apparatuses require a fan for pushing cooling air into the bleeding system, and a cooling chamber or a mixing chamber is provided in the bleeding pipe. It is necessary to connect the bleed pipe and the bleed pipe to have a special double structure, so that the structure of the bleed system is complicated, the equipment cost is high, and the maintenance is troublesome. In addition, during the operation, control of the fan for supplying cooling air must be performed at the same time as control of the fan for bleed air. There is a problem.

Further, in the above-mentioned conventional cement kiln bleeding apparatus, although the generation of coating on the inner wall surface of the bleeding system is suppressed by the flow of cooling air and the rapid cooling of exhaust gas, this can be completely prevented. Is not
The coating must be removed manually about once to three times a day, and there is also a problem that operation management is troublesome.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and the exhaust gas of a cement kiln is extracted from a kiln inlet hood by an extraction pipe, and the extracted exhaust gas is mixed with cooling air to lower the exhaust gas temperature. A first object of the present invention is to simplify the structure of a bleed system in a cement kiln flue gas bleeding treatment apparatus that performs treatment, and to facilitate adjustment during operation. A second object of the present invention is to make it possible to easily remove a coating generated in an extraction system.

[0007]

SUMMARY OF THE INVENTION A first aspect of the present invention is a cement kiln for extracting exhaust gas from a cement kiln from a kiln inlet hood by an extraction tube and mixing the extracted exhaust gas with cooling air to reduce the temperature of the exhaust gas. In the exhaust gas bleeding treatment device, the outlet side end of the bleeding tube is inserted with a gap around in the front end of the suction duct having an enlarged diameter portion gradually expanding toward the front end. Cement characterized by being connected to a suction duct, wherein a negative pressure is applied, and a bleed suction device that extracts exhaust gas from a bleed pipe to a suction duct and sucks outside air as cooling air from the gap to flow into the suction duct. It is intended to provide a kiln exhaust gas extraction device.

In the first aspect of the present invention, a suction duct is connected to a main exhaust duct of a cement kiln facility on an upstream side of an exhaust suction device interposed between the main exhaust ducts. That the suction duct is also movable, that the suction duct is movable in the central axis direction, that a plurality of rectifying plates partition a gap between the bleed pipe and the suction duct in parallel with the central axis of the suction duct, and that the suction duct is provided. A straight exhaust duct connected straight to the suction duct, which is connected to the rear end, and a branch exhaust duct branched from the straight exhaust duct are provided, and a bleed suction device is connected to the branch exhaust duct, The rear end of the straight exhaust duct is openable and closable, and at least the coating adhering to the bleed pipe is inserted through the rear end of the straight exhaust duct to remove the coating. Moving means for moving the high-pressure water lance forward and backward by a high-pressure water lance comprising a water supply pipe to which high-pressure water is supplied and a high-pressure water injection nozzle provided at the end of the water supply pipe. The device must have a bleed pipe with the inlet end cut off diagonally to the central axis, and with the inlet end protruding into the kiln inlet hood and with the inlet facing down. The preferred embodiments of the present invention include that the bleed pipe is attached obliquely with the inlet side down, and that the bleed pipe has cooling means for the bleed pipe.

A second aspect of the present invention is the first aspect of the present invention.
In the cement kiln exhaust gas extraction apparatus according to the above, the flow rate of the exhaust gas to be extracted at the inlet end of the extraction pipe is set to 5
A method for operating a cement kiln exhaust gas extraction device, characterized in that the exhaust gas temperature on the side of the smallest diameter portion of the enlarged diameter portion is 350 ° C. or lower while the pressure is set to 10 to 10 m / sec.

In a third aspect of the present invention, in the cement kiln exhaust gas bleeding apparatus according to the first aspect of the present invention which particularly has means for cooling the bleed pipe, the flow rate of the exhaust gas to be bled at the inlet side end of the bleed pipe. Is 5 to 10 m / sec, and the exhaust gas temperature on the minimum diameter side of the enlarged diameter portion is 35 m / sec.
A method for operating a cement kiln exhaust gas bleeding apparatus, characterized in that the temperature is set to 0 ° C. or lower and the bleed pipe is cooled within a range where the exhaust gas temperature at the outlet end of the bleed pipe does not fall below 850 ° C. .

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described with reference to FIGS.

As shown in FIGS. 1 and 2, a bleed pipe 3 is attached to the kiln inlet hood 2 through the wall 5 of the kiln inlet hood 2 leading to the cement kiln 1.
A part of the exhaust gas flowing through the inside of the cement kiln can be extracted by the extraction tube 3. The kiln inlet hood 2 side of the bleed tube 3 is an inlet 3a, and the opposite side (external side) is an outlet 3b.

A suction duct 4 is connected to the end of the bleed tube 3 on the outlet 3b side so that the central axis is aligned. In particular, as shown in an enlarged manner in FIG. 2, the suction duct 4 has a small-diameter portion 4a on the rear end side (the side opposite to the bleeding tube 3) and a front end side (the bleeding tube 3).
Side), and a large-diameter portion 4c connecting the two. That is, the suction duct 4 has an enlarged diameter portion 4c that gradually widens toward the distal end.
In the distal end portion of the suction duct 4 having the above, specifically, in the large-diameter portion 4b, the end of the bleeding pipe 3 on the outlet 3b side has a gap 6 around it.
Is plugged in.

As shown in FIG. 1, to the rear end of the suction duct 4 (on the side opposite to the bleeding pipe 3), the front end of a straight exhaust duct 7 linearly connected to the suction duct 4 is connected. Further, a branch exhaust duct 8 branched from an intermediate portion of the straight exhaust duct 7 is provided. The duct that leads the exhaust air in series with the suction duct 4 may be a single series and may be bent. However, in order to facilitate the cleaning described later, the straight exhaust duct 7 and the branch exhaust duct 8 as shown in FIG. It is preferable to configure.

The branch exhaust duct 8 is connected to a dust removing device 9 such as a bag filter or a cyclone. The dust removing device 9 is further connected to a bleed suction device 10 such as an induction fan. This bleed air suction device 10
It is connected to the suction duct 4 via the dust removing device 9, the branch exhaust duct 8, and the straight exhaust duct 7, the exhaust gas is extracted from the bleed pipe 3 by applying a negative pressure to the suction duct 4, and the extracted exhaust gas is exhausted from the straight exhaust duct 7. And the dust is sent to the dust removing device 9 through the branch exhaust duct 8 to remove dust. The exhaust gas removed by the dust removal device 9 is discharged as it is or after passing through a further purification device.

When a bag filter is used as the dust removing device 9, it is preferable that the exhaust gas guided through the branch exhaust duct 8 can be cooled so that the dust removing filter is not damaged by the heat of the exhaust gas. This cooling can be performed by water-cooling the area of the branch exhaust duct 8 near the dust removal device 9 or the like. However, as shown in FIG. Is convenient.

The bleeding suction device 10 may be dedicated to bleeding processing, but is interposed in the main exhaust duct (exhaust duct connected to the SP or NSP) of the cement kiln facility for discharging the exhaust gas from the cement kiln outside the system. Exhaust suction device (kiln induction fan)
And the device can be further simplified. That is, the end of the branch exhaust duct 8 shown in FIG. 1 is connected to the main exhaust duct on the upstream side (SP or NSP side) of the exhaust suction device interposed in the main exhaust duct of the cement kiln facility. The suction duct 4 can be connected to the exhaust suction device via the main exhaust duct, the branch exhaust duct 8 and the straight exhaust duct 7, and this exhaust suction device can also serve as the bleed suction device 10.

By the way, it is said that SOx contained in the exhaust gas of cement kiln is removed by reacting with CaO as a cement raw material when passing through SP or NSP. Since it is taken out without passing through, the content of SOx is usually large.

If the suction duct 4 is connected upstream of the exhaust suction device of the main exhaust duct as described above, the exhaust gas which has been subjected to the bleeding process to the exhaust gas in the main exhaust duct which is at a high temperature and contains the raw material dust in the dust can be obtained. Immediately after the merging, the SOx contained in the exhaust gas which has been stirred and mixed by the exhaust suction device and has been subjected to the bleeding treatment can be effectively absorbed by the raw material dust contained in the exhaust gas in the main exhaust duct. Therefore,
The SOx can be removed from the extracted exhaust gas without using any special SOx removal equipment.

FIG. 1 shows a cement kiln with NSP having a main exhaust duct connected to a chimney from an NSP through a boiler, a kiln induction fan, a raw material dryer, a humidity control tower, an electric dust collector, and an electric dust collector induction fan. The end of the branch exhaust duct 8 of the bleed air treatment device is connected to three points immediately before the kiln induction fan (A), immediately before the raw material dryer (B), and immediately before the chimney (C), and the SOx concentration of the exhaust gas is detected by SOx. Table 1 shows the results of measurement using a tube (0.5 ppm is the detection limit).

[0021]

[Table 1]

The rear end of the straight exhaust duct 7 (the side opposite to the side connected to the suction duct 4) can be opened and closed by an opening / closing lid 12. If the rear end of the straight exhaust duct 7 is made openable and closable and can be inserted into the straight exhaust duct 7 from the rear end when opened and has a cleaning means capable of removing the coating, coating on the bleed tube 3 occurs. When the bleeding is hindered, the cleaning means can be inserted from here to remove the coating, which is preferable. In particular, since the straight exhaust duct 7 is linearly connected to the suction duct 4, it is easy to insert the cleaning means.

As shown in FIG. 1, the cleaning means includes a water pipe 1 to which high-pressure water is supplied from a pump 13 via a flexible hose (not shown).
4 and high-pressure water (30
A high-pressure water lance 16 composed of a high-pressure water injection nozzle 15 for injecting 0 to 400 kgf / m ² ) is optimal. The high-pressure water injection nozzle 15 is preferably a rotary type that rotates in reaction to the high-pressure water injection, because unevenness in the removal of the coating does not easily occur.

The high-pressure water lance 16 may be manually moved forward and backward, but it is preferable to provide a moving device for moving the high-pressure water lance 16 forward and backward in order to further facilitate the cleaning operation (coating removal operation). . The mobile device is not limited to a particular type, for example,
The moving device shown in FIG. 1 includes a rack 17 provided on a water guide tube 14 slidably held back and forth, and a pinion gear 18 that meshes with the rack 17 and rotates. That is, when the pinion gear 18 is rotated counterclockwise in FIG. 1, the high-pressure water lance 16 moves leftward in FIG. 1 (forward) due to the engagement of the pinion gear 18 and the rack 17. 1 clockwise, the high pressure water lance 1
Numeral 6 moves (retreats) rightward in FIG.

Since the coating is likely to occur in the bleed pipe 4 in this apparatus, generally, when the high-pressure water injection nozzle 15 is inserted into the straight exhaust duct by a length that reaches the bleed pipe 3, the high-pressure water Is ejected from the high-pressure water injection nozzle 15, and the small-width advance / retreat is repeated as necessary. Then, the supply of high-pressure water is stopped, the pinion gear 18 is rotated in the reverse direction, and the high-pressure water lance 16 is retracted and taken out. Good.

Next, the device according to the present invention will be further described together with the method of operating the above device.

The operation of the above apparatus is performed by operating the bleed air suction device 10 to make the inside of the suction duct 4 a negative pressure. When the inside of the suction duct 4 becomes negative pressure due to the operation of the bleed suction unit 10, part of the exhaust gas in the kiln inlet hood 2 is bleed by the bleed pipe 3, Is sucked into the intake duct 4 as cooling air and flows therein.

The bleeding by the bleeding pipe 3 is performed at the inlet 3 of the bleeding pipe 3.
The process is performed so that the flow rate of the exhaust gas at the end on the a side is 5 to 10 m / sec. The diameter of the bleed tube 3 can be determined in advance in consideration of the operating conditions so that the above flow rate can be easily obtained. Fine adjustment of the flow speed during operation is performed by adjusting the negative pressure in the bleed tube 3. When the flow rate of the exhaust gas exceeds 10 m / sec, it becomes easy to excessively suck the dust of the cement raw material in addition to the volatile components such as alkali chloride gas.
When the flow rate of the exhaust gas is less than 5 m / sec,
Insufficient amount of air extraction makes it difficult to reduce the concentration of volatile components in the equipment by the air extraction.

The outside air sucked in from the gap 6 between the bleed pipe 3 and the suction duct 4 together with the bleed air flows in along the inner surface of the enlarged diameter portion 4c of the suction duct 4 shown in FIG. It flows obliquely in the direction of the central axis, and the outlet 3b of the intake pipe 3
And the exhaust gas flowing into the suction duct 4 to cool the exhaust gas. The cooling of the exhaust gas by the suction of the outside air is performed so that the exhaust gas temperature on the minimum diameter side (the inlet portion of the small diameter portion 4a) of the enlarged diameter portion 4c is 350 ° C. or lower. If the temperature exceeds 350 ° C., the solidification of the volatile components by cooling is insufficient, and the coating easily occurs in the straight exhaust duct 7. Further, if this temperature is set too low, the amount of bleed gas of the exhaust gas becomes small and it becomes difficult to obtain the bleeding effect. Therefore, the temperature is preferably set to 200 ° C. or more.

The adjustment of the cooling temperature of the exhaust gas due to the confluence of the outside air in the intake duct 4 is performed by adjusting the ratio of the amount of outside air sucked to the amount of exhaust gas extraction. This adjustment is
This can be easily performed by adjusting the overlapping length of the large-diameter portion 4b of the suction duct 4 and the bleed tube 3 in the central axis direction. That is, by increasing the overlap length, it is possible to reduce the outside air suction amount and increase the exhaust gas extraction amount, and conversely, by shortening the overlap length, increase the outside air suction amount and increase the exhaust gas amount. The amount of bleed air can be reduced. Therefore, the suction duct 4 is preferably movable in the axial direction. In the illustrated device, a portion of the straight exhaust duct 7 immediately after the suction duct 4 is made expandable and contractible in the center axis direction, and this portion is expanded and contracted to be slidable in the center axis direction.

In operation, it is preferable to measure the temperature of the exhaust gas cooled by the joining of the outside air and monitor the fluctuation. In particular, when the thickness of the coating formed on the bleed tube 3 is increased and the amount of bleed exhaust gas is reduced, the above-mentioned temperature is greatly reduced, so that the cleaning time can be known. The monitoring of the exhaust gas cooling temperature can be performed by providing a temperature sensor near the minimum diameter portion of the enlarged diameter portion 4c. In addition, by previously grasping the relationship between the exhaust gas temperature at the measurement site and the exhaust gas temperature near the minimum diameter portion of the enlarged diameter portion 4c, for example, the exhaust gas temperature in the branch exhaust duct 8 can be measured to replace the exhaust gas temperature. Can also.

The small diameter portion 4a constituting the intake duct 4 (FIG. 2)
) Is 1 to 1 of the internal cross-sectional area at the outlet 3 b of the bleed tube 3.
It is preferably 1.5 times, and the internal cross-sectional area in the cross section orthogonal to the central axis of the large diameter portion 4b (see FIG. 2) is 2-3 times the internal cross-sectional area at the outlet 3b of the bleed tube 3 Is preferred. If the internal cross-sectional area of the small-diameter portion 4a is too small, the pressure loss increases, the capacity of the bleeding suction device 10 increases, and coating tends to occur at the inlet of the small-diameter portion 4a. Is too large, the mixing of the outside air and the exhaust gas becomes insufficient, and coating tends to occur on the suction duct 4 and thereafter. Also,
If the internal cross-sectional area of the large-diameter portion 4b is too small, it is difficult to suck outside air from the gap 6, and if the internal cross-sectional area of the large-diameter portion 4b is too large, the sucked external air flows back through the bleed tube 3. And bleeding is easily inhibited.

The angle of the large-diameter portion 4c connecting the small-diameter portion 4a and the large-diameter portion 4b having the above-mentioned size to the central axis is 30 to 60 °.
It is preferred that If the angle is too small, the enlarged diameter part 4c
Becomes too long, and coating is easily generated in the enlarged diameter portion 4c. Conversely, if the angle is too large, high-temperature exhaust gas tends to blow out from the gap 6 between the intake duct 4 and the bleed pipe 3.

The bleed tube 3 is exposed to a high temperature.
If it is exposed to a temperature exceeding 00 ° C., it is easy to be broken by a general heat-resistant material. As a cooling means, a water jacket can be used. When using the bleed tube 3 having this cooling means and performing cooling so that the bleed tube 3 is kept at 1000 ° C. or lower, it is preferable to cool the exhaust gas at the outlet 3b of the bleed tube 3 within a range not lower than 850 ° C. . When the temperature of the exhaust gas at the outlet 3b is equal to or less than 850 ° C., the coating is easily generated in the bleed tube 3.

In the apparatus according to the present invention, as shown in FIG. 3, the gap 6 between the bleed pipe 3 and the suction duct 4 is
It is preferable to have a plurality of rectifying plates 19 that partition in parallel with the central axis of. By providing this rectifying plate 19, it is easy to align the flow of the sucked outside air with the flow of the extracted exhaust gas,
It is possible to maximize the flow velocity at the portion where the suctioned outside air and the extracted exhaust gas merge, and it is easy to promote the mixing of the two and to suppress the exhaust gas from blowing out from the gap 6.

It is preferable that six to ten rectifying plates 19 are provided at equal intervals in the circumferential direction of the bleed tube 3 in order to reliably obtain the rectifying action. In addition, the straightening plate 19 may be fixed to both the bleed tube 3 and the suction duct 4, but when the suction duct 4 is movable in the center axis direction as described above,
It may be fixed to one of the bleed tube 3 and the suction duct 4. In the illustrated example, it is fixed inside the suction duct 4.

The end of the bleed tube 3 on the inlet 3a side is as shown in FIG.
As shown in FIG. 2 and FIG. 2, it may be cut perpendicularly to the central axis, but as shown in FIG. Part into the kiln entrance hood 2 and the entrance 3
It is preferable that a is attached with a facing downward.
This makes it easier to prevent the entrance 3a from being blocked by the coating that hangs in an icicle shape from the inner surface of the wall 5 of the kiln entrance hood 2.

For the same reason as described above, as shown in FIG. 5, it is preferable to attach the bleeding pipe 3 obliquely with the inlet 3a side down. In this case, the entrance 3a
The side end may be cut perpendicularly to the center axis, but as shown, it is assumed to be cut obliquely to the center axis, and the end of the inlet 3a side is located inside the kiln inlet hood 2. And the inlet 3a is downwardly mounted, the inlet 3a can be directed directly downward, and the above-described closing prevention can be further facilitated.

[0039]

The present invention has been described above, and has the following effects.

(1) Just by attaching the intake duct 4 to the bleed pipe 3 with a gap 6 around it, the suction duct 4
Outside air can be taken in from the gap 6 as cooling air without using a fan for sending cooling air into the inside, and the exhaust gas can be cooled by the outside air with a simple structure. Therefore, equipment costs can be reduced,
Maintenance work can be reduced. Further, in the operation, control of the fan for supplying the cooling air is not required, and the trouble of the adjustment until the steady operation and the adjustment accompanying the condition change are reduced.

(2) At the rear end of the suction duct 4, a straight exhaust duct 7 connected to the suction duct 4 in a straight line is connected so that the rear end of the straight exhaust duct 7 can be opened and closed. By providing a cleaning means which can be inserted from the rear end to remove the coating, the coating generated on the bleed pipe 3 can be easily removed by inserting the cleaning means from the rear end of the straight exhaust duct 7. Therefore, it is possible to greatly reduce the burden of the cleaning work that must be performed periodically.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a cement kiln exhaust gas bleeding apparatus according to the present invention.

FIG. 2 is an enlarged sectional view of the vicinity of a suction duct and a bleed pipe in FIG.

FIG. 3 is a cross-sectional view showing a case where a current plate is provided in a gap between a bleed pipe and a suction duct.

FIG. 4 is a cross-sectional view showing a case of using a bleed tube whose end on the inlet side is cut obliquely with respect to a central axis.

FIG. 5 is a cross-sectional view showing a case where the bleeding pipe is attached obliquely with the inlet side facing downward.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cement kiln 2 Kiln inlet hood 3 Bleed pipe 3a Inlet 3b Outlet 4 Suction duct 4a Small diameter part 4b Large diameter part 4c Large diameter part 5 Wall part 6 Gap 7 Straight exhaust duct 8 Branch exhaust duct 9 Dust removal device 10 Extraction suction device 11 Outside air Inlet 12 Open / close lid 13 Pump 14 Water pipe 15 High-pressure water injection nozzle 16 High-pressure water lance 17 Rack 18 Pinion gear 19 Rectifier plate

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yasuhiko Kono 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata Inside the Aomi Plant of Denki Kagaku Kogyo Co., Ltd. Inside the Omi Plant of the Chemical Industry Co., Ltd. (72) Inventor Yasushi Matsuo 2209 Aomi, Omi-cho, Nishikubiki-gun, Niigata Prefecture Inside the Omi Plant of Denki Kagaku Kogyo Co., Ltd. Chemical Industry Co., Ltd.

Claims (11)

[Claims] 1. A cement exhaust gas bleeding apparatus for extracting exhaust gas from a cement kiln from a kiln inlet hood through an extraction tube and mixing the extracted exhaust gas with cooling air to reduce the exhaust gas temperature and treat the exhaust gas gradually toward the front end. The outlet end of the bleed tube is inserted with a gap around it into the tip of the suction duct that has an enlarged diameter portion that spreads out. An exhaust gas extraction device for cement kiln exhaust gas, wherein an exhaust gas suction device for extracting exhaust gas and sucking outside air from the gap as cooling air to flow into the suction duct is connected to the suction duct. 2. A suction duct is connected to a main exhaust duct of a cement kiln facility on an upstream side of an exhaust suction device interposed between the main exhaust duct, and the exhaust suction device also serves as a bleed suction device. The cement kiln exhaust gas bleeding apparatus according to claim 1, wherein: 3. The exhaust gas extraction apparatus for cement kiln exhaust gas according to claim 1, wherein the suction duct is movable in a central axis direction. 4. A cement kiln exhaust gas extraction process according to claim 1, further comprising a plurality of rectifying plates for partitioning a gap between the extraction pipe and the suction duct in parallel with a central axis of the suction duct. apparatus. 5. A straight exhaust duct connected to the rear end of the suction duct and linearly connected to the suction duct, and a branch exhaust duct branched from the straight exhaust duct is provided.
A bleed air suction device is connected to the branch exhaust duct, and the rear end of the straight exhaust duct is openable and closable, and at least the coating adhering to the bleed pipe can be inserted and removed from the rear end of the straight exhaust duct. The cement kiln exhaust gas extraction apparatus according to any one of claims 1 to 4, further comprising a cleaning unit. 6. A moving device for moving the high-pressure water lance forward and backward with a high-pressure water lance comprising a high-pressure water supply nozzle and a high-pressure water injection nozzle provided at the tip of the high-pressure water pipe. 6. The method according to claim 5, wherein
A cement kiln exhaust gas bleeding apparatus according to item 1. 7. The bleed tube has an inlet end cut obliquely with respect to the central axis, and is attached with the inlet end protruding into the kiln inlet hood and the inlet facing downward. The cement kiln exhaust gas extraction apparatus according to any one of claims 1 to 6, wherein: 8. The cement kiln exhaust gas extraction apparatus according to claim 1, wherein the extraction pipe is obliquely attached with the inlet side facing downward. 9. The cement kiln exhaust gas extraction processing apparatus according to claim 1, further comprising a cooling means for an extraction pipe. 10. The cement kiln exhaust gas extraction apparatus according to claim 1, wherein the flow rate of the exhaust gas to be extracted at the inlet end of the extraction pipe is 5 to 10 m / min.
A method for operating a cement kiln exhaust gas extraction device, wherein the exhaust gas temperature on the side of the smallest diameter portion of the enlarged diameter portion is 350 ° C. or less. 11. The cement kiln exhaust gas extraction device according to claim 9, wherein the flow rate of the exhaust gas to be extracted at the inlet end of the extraction pipe is 5 to 10 m / sec, and the minimum diameter portion of the enlarged diameter portion. Exhaust gas temperature on the side of 350
C. or less, and the method for operating a cement kiln exhaust gas bleeding apparatus, characterized in that the bleed pipe is cooled within a range where the exhaust gas temperature at the outlet end of the bleed pipe does not fall below 850 ° C.