JP2001239132A - Method for removing chlorine in cement kiln exhaust gas via chlorine bypass and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for surely removing hazardous substances such as chlorine, and the like, in a chlorine bypass that is capable of surely removing hazardous substances such as chlorine, and the like, in a cement kiln exhaust gas. SOLUTION: In the method for removing chlorine in the cement kiln exhaust gas wherein a chlorine solidified matter is formed by cooling and curing chlorine adhering and condensing on a raw material and then the raw material having the chlorine solidified matter adhering and condensing thereon is collected and removed via the chlorine bypass to remove the chlorine in the cement kiln exhaust gas, cement raw materials are further supplied to the high temperature kiln exhaust gas in an exhaust gas passage 3C so that chlorine is made to adhere and condense on the raw materials in the high temperature exhaust gas in the exhaust gas passage 3C. Thus, the raw materials having the chlorine adhering and condensing thereon together with the kiln exhaust gas are extracted from an exhaust gas extraction opening into the chlorine bypass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a process for extracting and extracting a part of a kiln exhaust gas by a chlorine bypass.
Regarding a method for removing impurities such as chlorine from exhaust gas of cement kiln, and an apparatus used for the method,
The present invention relates to a method and an apparatus for removing chlorine in exhaust gas from a cement kiln by a chlorine bypass, which can reliably remove harmful substances such as chlorine by the chlorine bypass.

[0002]

2. Description of the Related Art In a cement kiln (a cement sintering apparatus) using, for example, a cement raw material (limestone or the like) containing a large amount of chlorine as a harmful substance, the chlorine concentration of a clinker is kept below a predetermined value, and In order to prevent coating troubles caused by high chlorine concentration in the kiln kiln and the lower part of the preheater by circulating chlorine inside the kiln and preheater, by extracting and extracting a part of the kiln exhaust gas from the kiln kiln A so-called chlorine bypass for removing chlorine contained in kiln exhaust gas is well known.

A cement sintering apparatus having such a chlorine bypass will be described with reference to FIG. In FIG. 4, 1
Is a kiln for cement firing, 1a is a burner for firing, 2 is a cooler for cooling the clinker fired in the kiln 1, and 3 is an inlet hood having a substantially rectangular cross section attached to the cement raw material supply side of the kiln 1. And the entrance hood 3
Constitutes a part of the passage for receiving the calcined raw material and the kiln exhaust gas passage at the kiln kiln bottom. 5 is a suspension preheater provided with a calciner 5b, 5a is a lowermost cyclone of the suspension preheater 5, 5c is a raw material supply pipe for supplying raw material to the preheater 5, 4 is an upper end of the inlet hood 3. And the suspension preheater 5
A rising duct (rising pipe) for supplying the kiln exhaust gas to the suspension preheater 5 via the calciner 5b. Reference numeral 6 denotes an exhaust fan of the suspension preheater 5, and an upper end 7 is connected to a lower portion of the lowermost cyclone 5a and a lower end thereof is connected to a lower portion of a side wall of the inlet hood 3 which intersects with a side wall on the kiln 1 side. A chute for feeding a high-temperature cement raw material (hereinafter, referred to as a calcined raw material) calcined in a calcining furnace 5b after being preheated by the suspension preheater 5b to the kiln 1; This is a duct for feeding to the furnace 5b.

The chlorine bypass 10 communicates with an exhaust gas extraction port 3a opened on a side wall located on the kiln side of the rising portion of the inlet hood 3 and has an exhaust gas exhaust gas cooling means fixedly attached to the side wall. A bleed pipe 11, a humidity control tower (spray tower) 13 which is connected to the bleed pipe 11 by an exhaust gas duct 12 a and has a water spray device 13 a therein;
An electric dust collector 14 serving as dust collecting means connected to an exhaust gas outlet of the humidity control tower 13 via a duct 12b; an exhaust fan 15 connected to a gas outlet of the electric dust collector 14 via a duct 12c; 15 gas outlets and duct 1
The stack includes a chimney (stack) 16 connected through 2d and a cooling fan 11a connected to the exhaust gas extraction pipe 11 by an air supply duct 11b. Reference numeral 11c denotes a cooling air intake of the exhaust gas extraction pipe 11.

[0005] Dust transport equipment 17 including a screw conveyor, a bucket elevator and the like is connected to the lower part of the humidity control tower 13 and the lower part of the dust collector 14 of the dust collector 14. Hopper 18
It is connected to the. 19 is a dust carrying vehicle.

In the chlorine bypass 10 described above,
950-1200 from the exhaust gas extraction port 3a of the inlet foot 3
A part of the kiln exhaust gas at a high temperature of about ° C. (for example, about 30% by volume of the kiln exhaust gas) is bled (extracted) with a part of dust and taken into the chlorine bypass 10. The taken-in kiln exhaust gas as the bleed gas is mixed with air sent from the cooling fan 11a in the mixing chamber inside the bleed tube 11 and cooled to about 300 to 350 ° C. This prevents dust from adhering and sticking (so-called coating) to the inner wall surface of the bleed pipe 11 and the inner surface of the duct of the bypass equipment thereafter, and also prevents 950-950
High-concentration gas (steam) -like chlorine contained in high-temperature extracted gas of about 1200 ° C [mostly volatile, gaseous K
Cl (potassium chloride) or NaCl (sodium chloride)
Is cooled, liquefied and solidified to form a chlorinated product.

Thereafter, the bleed gas is discharged from the outlet of the bleed tube 11 together with the chlorinated solids and dust as chlorine and sent to the humidity control tower 13 through the duct 12a. It is further cooled to about ° C. Thereby, the electric resistance value (specific resistance value) of the dust is reduced, and the dust is easily collected by the electric dust collector 14 downstream. Part of the dust and the solidified chlorine is taken out from the lower outlet of the humidity control tower 13 and transferred to the dust transport facility 17.

The bleed gas or the like that has exited the humidity control tower 13 is introduced into an electric precipitator 14 through a duct 12b, where the remaining chlorinated solids such as KCl or NaCl and dust are collected, and the lower discharge port is provided. Is transferred to the dust transport facility 17 via The chlorinated solids and the dust transferred to the dust transport facility 17 are transferred to the dust storage hopper 18 by the dust transport facility 17.
To be stored here and extracted by a dust exporter as appropriate. The clean gas is discharged from the chimney 16 to the atmosphere via the exhaust fan 15.

However, the chlorinated product such as KCl or NaCl contained in the bleed gas discharged from the humidity control tower 13 and introduced into the electrostatic precipitator 14 is a very fine particle by itself and extremely remarkable. Since it is lightweight and has a high electric resistance value, there is a problem that it is difficult to be collected by the electrostatic precipitator 14 and collection is difficult. Further, even if once collected by the dust collecting electrode, when the electrode plate is hammered, it does not fall into the collecting hopper below the electric dust collector 14 and re-scatters on the gas flow in the dust collector, thereby making the electric dust collector There is a problem that the collection performance of the No. 14 is reduced.

In view of these problems, in order to ensure the dust collection performance of the electric dust collector, as shown in FIGS. 5 and 6, the raw material from the lowermost cyclone 5a of the suspension preheater 5 to the kiln is removed. A dispersing plate 20 is attached to the distal end of the feeding chute 7 as a dispersing supply means capable of adjusting the amount of insertion into the chute 7.
By adjusting the insertion amount, a part of the high-temperature calcined material of about 800 to 860 ° C., which slides down the feed chute 7, collides with the dispersion plate 20, is scattered, and is wound up by the kiln exhaust gas to exhaust gas of the bypass facility 10. A method of causing the air to reach the bleeding port 3a and sucking it is used.

Here, the mounting state of the dispersion plate will be described with reference to FIGS. 5 and 6. As shown in FIG. 5, at the entrance hood 3 of the kiln 1, a rising portion of the entrance hood 3 on the kiln side is provided. As described above, an exhaust gas extraction port 3a to which the exhaust gas extraction pipe 11 of the chlorine bypass 10 is connected and installed is provided on the side wall, and a side wall perpendicular to the wall surface is provided below the exhaust gas extraction port 3a. The chute 7 of the lowermost cyclone 5a is connected with the raw material supply opening 7a located at a position close to the raw material inlet side end face of the kiln 1.

Then, as shown in FIG.
Near the starting point of attachment to the inlet foot 3 at the lower part of the chute, a horizontal dispersion plate 20 as a means for dispersing and supplying the calcined raw material penetrates through the lower side wall of the chute 7 and has an opening 7 to the inlet foot 3.
The dispersion plate 20 is inserted and installed inside the chute 7 so as to face the a. The dispersion plate 20 rotates the screw shaft connected to the dispersion plate 20 with the handle 21 to reduce the insertion stroke into the short. It is adjustable.

However, the method using such a dispersion plate 20 is based on the fact that chlorine compounds such as KCl and NaCl as vaporized gaseous (vaporous) chlorine are relatively coarse and have low electric resistance. The calcined raw material is wound up with the kiln exhaust gas by the dispersing plate 20 so as to be introduced into the electrostatic precipitator 14 after adhering and aggregating on the particle surface of the high-temperature calcined raw material as described above. The purpose is to attach and coagulate the compound and to suck the compound into the chlorine bypass 10 through the exhaust gas extraction port 3a.

[0014]

However, as described above, KCl and NaCl are added to the high-temperature calcined raw material at 800 to 860 ° C.
Although the method of attaching and condensing chlorine compounds such as has the advantage that the calcined raw material supplied inside the inlet hood as the exhaust gas passage of the kiln kiln can be conveniently used inside the inlet hood of the same part, However, even if the dust collection rate of the chlorine compound by the electric dust collector is not satisfied, even if a sufficient amount of the calcined raw material is supplied inside the inlet hood by being blown up by the exhaust gas, the chlorine compound (chlorinated product) is still present. Of smoke was emitted from the chimney.

The reason is that the calcined raw material for adhering and coagulating the gaseous chlorine compound has a relatively high temperature of 800 to 860 ° C., so that the calcined raw material contains a gaseous chlorine compound at a high temperature of 950 to 1200 ° C. Even if touched, it is difficult for the chlorine compound to drop to a temperature at which the chlorine compound liquefies and condenses and further solidifies, or it takes time for the chlorine compound to contact and adhere to and condense on the surface of the calcined raw material, It is conceivable that the condensation and condensation, that is, the fixation, of the material on the calcined raw material is difficult to be performed smoothly and is uncertain.

Further, the exhaust gas containing the gaseous chlorine compound accompanying the calcined raw material extracted at the bleeding pipe 11 at the inlet of the chlorine bypass 10 is cooled to a low temperature. There is also a problem that adhesion and condensation on the raw material for firing cannot be performed smoothly. That is, as shown in FIG. 5, the extraction pipe 11 attached to the exhaust gas extraction port 3 a of the inlet hood 3 cools the high-temperature exhaust gas as the extraction gas to be taken in and simultaneously removes the inner wall surface of the outer wall constituting the outer shell of the extraction pipe 11. Since it is necessary to cool to prevent dust from adhering to the inner wall surface and to prevent coating, high-temperature exhaust gas containing a gaseous chlorine compound accompanied by a calcined raw material passes through the bleeding port 3 a of the inlet hood 3 and the bleeding pipe 11. The cooling air supplied from the cooling fan 11a is taken into the mixing chamber 11d at the center of the bleeding tube 11 from the axial direction of the bleeding tube 11, while being formed in a spiral shape of the bleeding tube from a direction perpendicular to the axis of the bleeding tube 11. Mixing chamber 11 of the bleed tube in a tangential spiral along the inner wall of the outer wall
d, the high-temperature bleed gas and the cooling air are mixed in the mixing chamber, the temperature is lowered to 300 to 350 ° C., and the cooled bleed gas is extracted in a direction orthogonal to the axis of the bleed tube. And is led out to the exhaust gas duct 12a.

For this reason, in the mixing chamber of the bleed tube 11,
The gaseous chlorine compound is cooled by the cooling air to form a solid chlorinated product. Since the chlorinated product is a very light-weight fine particle (submicron particle) as described above, It is difficult for centrifugal force due to the cooling air flowing spirally from the tangential direction to be exerted, and it gathers at the center of the mixing chamber of the bleeding tube and remains alone.On the other hand, the calcined raw material is relatively coarse and the cooling air By the centrifugal force being exerted and swirling along the inner wall side of the mixing chamber, the chlorine solids and the calcined raw material are separated, and the opportunity for the chlorine solids to come into contact with the calcined raw material is extremely small. Adhesion and condensation on the calcined raw material was not performed smoothly, and thereafter it was passed through the exhaust gas duct by itself and taken into the electric dust collector.
A predetermined collection rate cannot be secured by the electric dust collector.

On the other hand, in the above-mentioned method of adjusting the amount of insertion of the dispersion plate 20 to adjust the amount of winding of the calcined raw material, the inside of the chute 7 where the dispersion plate 20 is installed and the kiln to which the chute 7 is connected The inside (inner wall surface) of the inlet hood 3 has a large amount of adhesion and detachment of the coating. Therefore, depending on the adhesion state of the coating in the vicinity, the amount of winding of the calcined raw material varies greatly even with the same insertion amount of the dispersion plate 20. If the hoisting amount is small, the dust collecting performance of the electric dust collector 14 deteriorates, and the chimney 16
A large amount of raw material is wound up, and the dust collecting performance of the electrostatic precipitator 1 is good if the amount of raw material wound up is large, but if the amount is too large, most of the wound up raw material is temporarily passed through the rising duct 4. To the furnace 5b, the lowermost cyclone 5
a, the material is collected by the cyclone 5a, and reaches the chute 7 again. A large amount of the material circulates, increasing the pressure loss of the system, clogging the chute 7 and the amount of the material entering the kiln 1. At last, it may be impossible to drive, for example, due to a large fluctuation of the vehicle.

Further, if the amount of the raw material rolled up is large, the amount of dust collected in the chlorine bypass 10 also increases, and there is a problem that the amount of work for handling the collected dust increases. For this reason, the performance of the electrostatic precipitator 14 is somewhat sacrificed, but the stable operation of the kiln is emphasized. Therefore, the insertion amount of the dispersing plate 20 is suppressed as much as possible, and the amount of the raw material to be wound is limited. , The performance of the electrostatic precipitator 14 is not exhibited, and a large amount of smoke is discharged from the chimney. As described above, even when the calcined raw material is dispersed and supplied by changing the insertion amount of the dispersion plate, it is difficult to adjust the supply amount, which is uncertain.

The present invention has been made in view of the problems of the conventional chlorine removal method using the calcined raw material as described above.
By using a preheated and / or calcined raw material and a cement raw material in combination as a medium for adhering and condensing chlorine, the medium on which chlorine is adhered and condensed is reliably collected and removed in a chlorine bypass. By ensuring the removal of harmful substances such as chlorine in the bypass,
It is an object of the present invention to obtain a method and an apparatus for removing chlorine in a cement kiln exhaust gas by a chlorine bypass which can surely remove harmful substances such as chlorine in the cement kiln exhaust gas.

[0021]

In order to achieve the above object, the present invention has the following arrangement.

(1) The preheated and / or calcined raw material collected in the lowermost cyclone of the preheater is dispersed and supplied into high temperature kiln exhaust gas in an exhaust gas passage at the tail of a kiln kiln, and chlorine is adhered and condensed to the raw material. The raw material to which the chlorine is adhered and condensed is extracted together with a part of the kiln exhaust gas from the exhaust gas extraction port of the exhaust gas passage of the kiln kiln bottom to a chlorine bypass, and the exhaust gas is cooled by the chlorine bypass to be adhered and condensed to the raw material. A cement kiln using a chlorine bypass in which the chlorine in the exhaust gas of the cement kiln is removed by cooling and solidifying the produced chlorine to form a chlorinated product, and collecting and removing the raw material on which the chlorinated product is adhered and condensed by a chlorine bypass. In the method for removing chlorine in exhaust gas, by supplying further low-temperature cement raw material to the kiln high-temperature exhaust gas in the exhaust gas passage, Chlorine to biological material in a high temperature exhaust gas passage deposited condensed raw materials the chlorine is attached condensed were also to the configurations to extract the chlorine bypass the exhaust gas extraction opening with kiln exhaust gas.

(2) In the method for removing chlorine in exhaust gas of a cement kiln by the above-mentioned (1) chlorine bypass, the supply of raw material into the exhaust gas in the exhaust gas passage is blown toward the exhaust gas extraction port. The configuration was adopted.

(3) In the method for removing chlorine in exhaust gas from a cement kiln by chlorine bypass according to the above (1) or (2), the preheated and / or calcined raw material supplied to the exhaust gas passage has a temperature of 800-800. 860 ° C., the raw material has a temperature of 50 to 70 ° C., and the exhaust gas in the exhaust gas passage has a temperature of 9 ° C.
The temperature was set to 50 to 1200 ° C.

(4) In the method for removing chlorine from the exhaust gas of a cement kiln by the chlorine bypass of (1), (2) or (3), the raw material supplied to the exhaust gas passage comprises:
A configuration was adopted in which a part of the raw material sent to the preheater was taken out and used.

(5) In the method for removing chlorine in exhaust gas of a cement kiln by the chlorine bypass of (2) or (3) or (4), the raw material is directed toward the exhaust gas extraction port into the exhaust gas passage. All the blowing is performed in a region where the flow rate of the exhaust gas is low, such as a portion where the flow of the exhaust gas in the exhaust gas passage is stagnant.

(6) In the above method (5) for removing chlorine in exhaust gas from a cement kiln by chlorine bypass, the raw material is blown into the exhaust gas passage on the side wall located on the kiln side of the exhaust gas passage. The exhaust gas extraction port opened toward the corner of the exhaust gas passage is opened from a position close to the corner of the side wall intersecting the side wall where the exhaust gas extraction port is opened.

(7) In the above method (2) or (3) or (4) or (5) or (6), in the method for removing chlorine in exhaust gas of a cement kiln by chlorine bypass, the preheating and / or calcining is performed. The amount of the raw material dispersed and supplied into the kiln high-temperature exhaust gas in the exhaust gas passage was kept to a minimum, and the raw material was blown into the exhaust gas extraction port in such an amount as to make up the shortage.

(8) In the above method (7) for removing chlorine in the exhaust gas of a cement kiln by chlorine bypass, the dispersed supply amount of the preheated and / or calcined raw material is used to secure the performance of an electric dust collector as a dust collector. The amount of the raw material to be blown was adjusted to be slightly insufficient, and the amount of the raw material to be blown was adjusted according to the dust collection state of the electric dust collector.

(9) The preheated and / or calcined raw material collected in the lowermost cyclone of the preheater is discharged into kiln high-temperature exhaust gas in the exhaust gas passage at the bottom of the kiln kiln via a discharge chute connected to the lower portion of the cyclone. The chute adheres and condenses to the raw material in the exhaust gas passage by causing the chute to collide with the dispersing and supplying means attached to the inside of the chute so that the amount of insertion into the chute can be adjusted. The obtained raw material is extracted from the exhaust gas extraction port of the exhaust gas passage at the bottom of the kiln kiln together with a part of the kiln exhaust gas to a chlorine bypass, and the exhaust gas is cooled by cooling means to cool and solidify the chlorine adhered and condensed on the raw material. To remove the chlorine in the exhaust gas from the cement kiln by collecting and removing the raw material on which the chlorinated product is adhered and condensed by dust collecting means. In the apparatus for removing chlorine in the exhaust gas of a cement kiln by means of a chlorine bypass, raw material supply means for supplying a low-temperature cement raw material is further provided in the exhaust gas passage of the kiln kiln bottom. Chlorine was adhered and condensed on the raw material, and the raw material on which the chlorine was adhered and condensed was extracted together with the kiln exhaust gas from the exhaust gas extraction port to a chlorine bypass.

(10) In the apparatus for removing chlorine from a cement kiln exhaust gas by chlorine bypass according to the above (9), the raw material supply means may be a raw waste gas opening opening directed to the exhaust gas extraction port in a high-temperature exhaust gas passage at the end of a kiln kiln. A raw material blowing port and a raw material pneumatic transport device connected to the raw material blowing port were provided.

(11) In the apparatus for removing chlorine from cement kiln exhaust gas by chlorine bypass according to the above (10), the exhaust gas extraction port is located at a position close to the corner of the kiln side wall at the rising portion of the exhaust gas passage at the bottom of the kiln kiln. Provided with an opening,
The raw material blowing port is provided at a position closer to the corner of the side wall intersecting the side wall where the exhaust gas extraction port is provided.

(12) In the apparatus for removing chlorine from cement kiln exhaust gas by chlorine bypass according to the above (10) or (11), the raw material air transport device is provided in the middle of the cement raw material transport route for the preheater. A raw material hopper to which a part is supplied, an accelerating tube connected to a lower outlet of the raw material hopper via a variable speed rotary feeder, and a raw material for communicating the accelerating tube and the raw material blowing port It was configured to include a transport pipe and a blower connected to the acceleration pipe.

[0034]

According to the above method (1) or the structure of the apparatus (9), the temperature of the inside of the kiln exhaust gas passage at the bottom of the kiln, for example, the inlet hood, is 950-1200 ° C., and the high-temperature exhaust gas contains chlorine. The preheated and / or calcined raw material having a temperature of, for example, 800 to 860 ° C. (hereinafter, also referred to as a preheated / calcined raw material) as a condensed condensing medium is dispersed and supplied through the dispersion supplying means. The temperature is 5
A raw cement raw material at a low temperature of 0 to 70 ° C is supplied. As a result, KC as chlorine contained in high-temperature exhaust gas
1 or a gaseous (steam) chlorine compound such as NaCl,
While being adhered and condensed on the surface of the high-temperature preheated / calcined raw material,
It adheres and condenses on the surface of the low temperature raw material.

The preheated and calcined raw material has a high temperature of, for example, 800 to 860 ° C., and it takes a long time for the chlorine compound in the kiln exhaust gas to adhere to the surface of the kiln and then condense. The raw material has a temperature of, for example, 50 to
It is a low temperature of 70 ° C, and the chlorine compound touching the surface is
It is instantaneously cooled to a temperature of, for example, about 600 ° C., which is solidified through liquefaction. The gaseous chlorine compound is easily adhered and condensed on the particle surface of the raw material during the process of cooling to the temperature, particularly when liquefied, and is easily fixed to the raw material.

The chlorine compound adheres and condenses on the surface of the raw material particles because the raw material of cement is 950 to 120 in the exhaust gas passage.
The raw material [calcium carbonate (CaCO ₃ )] is partially decarbonated by being supplied and exposed to a high-temperature exhaust gas atmosphere of 0 ° C., and chemically activated quicklime (Ca)
O), and it is considered that this is promoted by the fact that the chlorine compound in the liquefied state easily adheres and condenses to the activated particles in which the surface is made into quick lime and thus activated particles. As described above, the gaseous chlorine compound easily adheres and condenses to the particle surface of the raw cement material in a short time, that is, is fixed.

The raw material and the preheated / calcined raw material having the chlorine compound adhered and condensed on the surface as described above are supplied together with a part of the exhaust gas from the exhaust gas extraction port of the inlet hood, which is the exhaust gas passage at the bottom of the kiln kiln. Air is extracted (extracted) into the bypass, mixed with cooling air in a mixing chamber such as an extraction pipe provided as a cooling means provided in the bypass, and further cooled, for example, to a temperature of 300 to 350 ° C. The solidification of the chlorinated material adhering to the surface of the calcined raw material and the raw material is finally performed and ensured, and an opportunity to adhere and condense on the preheated / calcined raw material and the raw material is lost. The remaining part of the gaseous chlorine compound is converted into a solidified chlorine product.

The preheated / calcined raw material to which the chlorine compound is attached and condensed, the raw material, and the dust extracted with the exhaust gas are relatively coarse particles having a low electric resistance value. Yes, it is easily collected by a dust collecting electrode, for example, a dust collecting electrode of an electric dust collector, and is separated by being easily dropped into a lower collecting hopper by hammering an electrode plate.
In this way, chlorine is reliably removed.

However, in this configuration, both the preheating / calcining raw material and the raw cement material are used as the chlorine condensing and condensing medium, so that the degree of chlorine condensing and condensing is not good. In order to compensate for the shortage of the degree of adhesion and condensation of chlorine due to the preheated and calcined raw material, the degree of adhesion and condensation can be adjusted by adjusting the amount of raw material supplied to the exhaust gas passage having a good degree of adhesion and condensation.

Further, as described above, the dispersing and supplying means is based on the adhesion state (growth degree) of the dust coating on the inside of the discharge chute of the lowermost cyclone and the inner wall surface of the exhaust gas passage at the portion to which the chute is connected. The uncertainty in the adjustment of the amount of dispersion of the preheated / calcined raw material into the exhaust gas passage due to the adjustment (increase or decrease) of the insertion amount of a certain dispersion plate is eliminated. That is, for example, the insertion amount of the dispersion plate is minimized to minimize the dispersion amount of the preheating / calcining raw material, and the raw material supply amount is stably performed so as to compensate for the amount. The problem can be solved by increasing the supply amount of raw material having good adhesion and condensation properties.

Further, it is assumed that the coating of dust on the inner wall surface of the exhaust gas passage inside the discharge chute and at the portion where the chute is connected is extremely advanced, making it impossible to disperse the preheated and calcined raw materials. However, it can be supplemented by the supply of raw materials. These make it possible to reliably remove chlorine. By reducing the amount of the preheated / calcined raw material in this manner, the amount of the preheated / calcined raw material carried to the chlorine bypass is consequently reduced. Can be reduced to a small number.

Further, by providing the raw material supply means to a cement kiln (cement firing apparatus) having an existing chlorine bypass, which has been performing chlorine removal using a dispersion plate as a dispersion supply means, chlorine can be easily removed. The rate can be improved.

In the method (2) or the configuration of the apparatus (10), the raw material is supplied to the exhaust gas passage at the bottom of the kiln kiln.
The raw material is blown into the exhaust gas passage at a predetermined pressure toward the exhaust gas extraction port since the raw material is blown from the raw material injection port toward the exhaust gas extraction port opened in the exhaust gas passage by the pneumatic transport device. The raw material adhered and condensed on the surface overcomes the exhaust gas flow without being flown, and is more reliably taken into the exhaust gas extraction port, and the chlorine is reliably removed by the dust collecting means in the chlorine bypass.

By feeding the raw material to the raw material blowing port at a predetermined pressure by a pneumatic transport device and blowing the raw material, dust coating is generated on the inner surface of the exhaust gas passage such as the inlet hood near the blowing port. Even if it starts, the coating does not grow at the part of the raw material blowing port due to the blowing pressure, and the opening area is secured.

In the configuration of the above method (3), since the temperature difference between the raw material and the exhaust gas in the exhaust gas passage to which the raw material is supplied is large, the temperature drop of the gaseous chlorine compound is more reliably performed. Adhesion and condensation on the raw material particle surfaces during the liquefaction and solidification state change process due to the temperature drop are reliably performed. Therefore, the temperature of the exhaust gas is low and the adhesion and condensation property (degree) of chlorine is not good. Can be performed reliably.

In the method (4) or the configuration of the apparatus (12), a part of the raw cement material originally supplied to the suspension preheater of the cement kiln is extracted and used as a medium for removing chlorine. There is no need to separately prepare a medium, and the present invention can be easily implemented. In the configuration of the apparatus (12), the raw material stored in the raw material hopper can be cut out (discharged amount) by changing the rotation speed of the variable speed rotary feeder so that the raw material transport amount can be adjusted. Thus, the amount of the raw material blown into the exhaust gas passage can be adjusted.

This makes it possible to easily adjust the degree of attachment and condensation of the chlorine compound by the raw material, and to adjust the amount of the preheated / calcined raw material supplied to the exhaust gas passage by adjusting the insertion amount of the dispersed supply means, and Can be adjusted, and it is possible to compensate for the uncertainty of the adjustment of the dispersion amount of the preheating / calcining raw material by the dispersion supply means, and to surely perform chlorine removal. Can be.

The method (5) or (6) or (11)
In the configuration of the device, the raw material is blown into the exhaust gas passage in a region where the flow rate of the exhaust gas is low, such as a portion where the flow of the exhaust gas in the exhaust gas passage is stagnant. For example, when the raw material was blown into the exhaust gas passage, the exhaust gas extraction port was opened toward the exhaust gas extraction port that was opened on the side wall located on the kiln side of the exhaust gas passage toward the corner of the exhaust gas passage. This is performed from a raw material blowing port provided at a position close to the corner of the side wall intersecting the side wall.

Therefore, the region (part) of the exhaust gas passage through which the raw material passes from the raw material blowing port toward the exhaust gas extraction port is a region in which the kiln exhaust gas in the region away from the kiln is discharged vigorously and the flow speed is high. Since the flow rate of the kiln exhaust gas is slower than that of the above, and the region through which the raw material passes is closer to the corner of the kiln side wall of the exhaust gas passage, the exhaust gas flow rate is relatively small due to the resistance of the wall and the like. Area. For this reason, those areas become portions where stagnation occurs in the exhaust gas flow, and the phenomenon in which the raw material blown into the exhaust gas passage is pushed away by the exhaust gas flow and carried away is prevented. For this reason, chlorine removal using the raw material as an attached condensing medium is more reliably performed.

In the configuration of the above method (7), the uncertainty of the amount of dispersion of the preheated / calcined raw material by the dispersion supply means is eliminated as much as possible. Since chlorine is removed, chlorine can be reliably removed. Then, it is possible to minimize the amount of heat that is lost by removing the preheated / calcined raw material by the chlorine bypass and the amount of the preheated / calcined raw material.

In the configuration of the above method (8), the amount of raw material to be blown is increased or decreased according to the actual dust collection state (collection performance) at the time of operation of the electric precipitator, so that chlorine can be reliably removed. Can be easily controlled.

[0052]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described based on embodiments shown in the drawings. FIGS. 1, 2 and 3 show an apparatus for carrying out the method for removing chlorine in exhaust gas from a cement kiln by chlorine bypass according to the present invention.
2 is a schematic longitudinal sectional view of the kiln kiln bottom, FIG. 2 is a plan view taken along the line AA of FIG. 1 and shows the arrangement relationship between a raw material injection port and an exhaust gas extraction port, and FIG. It is a system diagram showing a transportation system. In the drawings of the present embodiment, the same portions as those in FIGS. 4 and 5 are denoted by the same reference numerals, and description thereof will be omitted. Further, the embodiment of the chlorine bypass of the present invention is the same as that of FIG. 4 described above, and the embodiment of the dispersion plate supply means for the preheating / calcining raw material is the same as that of FIG. Will be explained.

As shown in FIGS. 1 and 2, the kiln
A vertical wall 3 on the kiln 1 side of a rising portion having a rectangular cross section of an inlet hood 3 in which a kiln exhaust gas passage 3C is formed.
A, an exhaust gas extraction port 3a, which is an exhaust gas extraction port to the chlorine bypass 10, is opened, and a side wall perpendicular to the wall surface is provided below the exhaust gas extraction port 3a and on the raw material inlet side of the kiln 1. The raw material supply opening 7a is located at a position close to the end face, and a discharge chute 7 for raw materials (hereinafter, referred to as calcined raw materials) calcined in the calciner 5b and collected and discharged by the lowermost cyclone 5a is connected. Have been.

Then, as shown in FIG.
Near the starting point of attachment to the inlet foot 3 at the lower part of the chute, a horizontal dispersion plate 20 as a means for dispersing and supplying the calcined raw material penetrates through the lower side wall of the chute 7 and has an opening 7 to the inlet foot 3.
The dispersion plate 20 is inserted and installed inside the chute 7 so as to face the a. The dispersion plate 20 rotates the screw shaft connected to the dispersion plate 20 with the handle 21 to reduce the insertion stroke into the short. It is adjustable.

As a result, a part of the high-temperature calcined material of about 800 to 860 ° C. which is originally fed into the kiln 1 and slides down the feed chute 7 collides with the projection of the dispersion plate 20 into the chute 7. The exhaust gas is then scattered and wound up by the kiln exhaust gas to reach the exhaust gas extraction port 3a of the chlorine bypass 10 and to be sucked. By adjusting the protrusion amount (insertion amount) of the dispersion plate 20, the collision amount of the calcined raw material sliding down the chute 7 can be adjusted, and the dispersion amount can be adjusted.

On the other hand, as shown in FIG.
a is opened at a position close to one corner 3B of the kiln 1 side of the entrance hood 3 on the vertical wall 3A of the kiln 1 side of the rising section of the entrance hood 3 of the kiln kiln butt having a rectangular cross section, A cement raw material blowing port 30 is provided at a position close to the corner 3B on one wall intersecting with the wall 3A sharing the corner 3B.

That is, in FIG. 2, 3CLK is a central axis in the same direction as the longitudinal central axis of the kiln 1 of the entrance hood 3, 3CLR is a central axis of the entrance hood 3 in a direction orthogonal to the central axis 3CLK, and 11CL is The exhaust gas extraction port 3a and the central axis in the same direction as the central axis of the kiln 1 of the exhaust gas extraction pipe 11 in the longitudinal direction, and the exhaust gas extraction port 3a has its central axis 11CL inlet by a distance DL from the central axis 3CLK of the inlet hood 3. The raw material blowing port 30 is opened at a position closer to the corner 3B side of the hood 3, and the raw material blowing port 30 is opened at a position closer to the corner 3B side than the center axis 3CLR of the inlet hood 3 by a distance DW.

The opening of the raw material blowing port 30 is, as viewed in plan, as shown in FIG.
The X is attached to the opening of the exhaust gas extraction port 3a with the X approaching the base end (root) of the opening of the exhaust gas extraction port 3a on the side of the opening 3a away from the corner 3B. A conduit 55a, which is a short pipe for transporting the raw material, is attached to the raw material blowing port 30 so as to be inclined in a direction coinciding with the direction of inclination of the opening of the blowing port 30. Further, in the present embodiment, the raw material blowing port 30 is provided at a height substantially at an intermediate position of the opening of the exhaust gas bleeding port 3a as shown by a solid line in FIG.

Then, the short pipe 5 of the raw material blowing port 30
5a, as shown in FIG.
Are connected. Raw material pneumatic transportation device 5
Numeral 0 denotes a transportation path 51 that is branched from the discharge end of an air slider 42 in the transportation device 40 (transportation path) that transports raw materials to the suspension preheater 5 of the kiln 1, and the path 51 is connected. Small hopper 52 as a raw material hopper, a variable speed rotary feeder 53 connected to the outlet of the small hopper 52, and an acceleration tube 54 as a bend pipe connected to the outlet of the rotary feeder 53.
And a raw material transport pipe 5 connected to the outlet of the acceleration pipe 54.
5, and a blower 56 for supplying transport air to the acceleration tube 54.

The transport route 5 connected to the small hopper 52
1, a butterfly damper 51a is interposed, a load cell (weighing sensor) 52a is attached to the small hopper 52, and the small hopper 5
When a predetermined amount of raw material is stored in 2, the butterfly damper 51 is automatically closed, and when the raw material becomes less than a predetermined amount, the butterfly damper 51 is automatically opened and the raw material is supplied and stored. It is configured as follows.

The suspension preheater 5 of the kiln 1
The raw kiln raw material transporting device 40 connected to the raw raw material supply pipe 5c includes a large-capacity raw material silo 41, an air slider 42 connected to a raw material discharge port of the silo 41, and a raw material discharge end of the air slider 42. Elevator 43 connected to a hopper 44, a cushion hopper 44 connected to a material discharge end of the elevator 43, and a quantitative transporter 45 provided with a scale 45a connected to a material discharge port of the hopper 44.
And a bucket elevator 46 connected to the raw material discharge end of the fixed quantity transporter 45 and having an outlet connected to the raw material supply pipe 5c of the suspension preheater 5. The cushion hopper 44 has a load cell (weighing sensor) 4
4a is attached, and is configured to always be able to secure a constant holding amount.

In the apparatus for removing chlorine in the exhaust gas of a cement kiln by the chlorine bypass in such an embodiment, the high temperature kiln exhaust gas having a temperature of 950 to 1200 ° C. is, as shown by an arrow in FIG. The waste gas is discharged into the kiln inlet hood 3 from the exhaust gas outlet end of the kiln 1 on the raw material supply side, is changed into an upward flow, and rises in the inlet hood 3. And 800-860 calcined in the calciner 5b
The calcined raw material at a high temperature of ℃ is collected by the lowermost cyclone 5 a of the suspension preheater 5, and the outlet chute 7 connected to the lower part thereof and the inlet 7 through the lower opening 7 a of the chute 7 of the inlet hood 3. Exhaust gas passage 3 of Hood 3
As shown in FIG. 6, a part of the gas is collided with the dispersion plate 20 as dispersion supply means at the opening 7a and scattered, and is wound up by the ascending kiln exhaust gas to form a chlorine bypass. The exhaust gas bleeding port 3a of No. 10 is sucked.

The calcined raw material is wound up by the exhaust gas, rises, and reaches the exhaust gas extraction port 3a until it is sucked. Is attached to and condensed on the surface of the calcined raw material.

On the other hand, the blower 5 of the raw material pneumatic transportation device 50
6, the temperature sent through the transport pipe 50 by the transport air sent to the acceleration pipe 54 at a predetermined pressure is 50 °.
A raw cement raw material at a low temperature of 70 to 70 ° C. is blown from the raw material injection port 30 into the exhaust gas passage 3C toward the exhaust gas extraction port 3a of the chlorine bypass 10 at a predetermined pressure. The gas is sucked into the exhaust gas extraction port 3a of the chlorine bypass 10 together with the portion.

Since the raw material is thus blown into the exhaust gas passage 3C at a predetermined pressure, the raw material overcomes the upward flow of the exhaust gas, is reliably sent to the exhaust gas extraction port 3a, and is taken into the extraction port 3a. The raw material is reliably taken into the exhaust gas extraction port 3a for the following reasons (1) to (3).

(1) An exhaust gas extraction port 3a is opened at a position close to a corner 3B of the inlet hood 3 on a vertical wall 3A on the kiln 1 side of the inlet hood 3, and the corner of one wall intersecting the wall 3A. Since the cement raw material injection port 30 is opened at a position close to 3B, the region (part) of the exhaust gas passage 3C through which the raw material passes from the raw material injection port 30 toward the exhaust gas extraction port 3a is: The kiln exhaust gas in the area away from the kiln 1 is vigorously discharged and the flow velocity is high, that is, in FIG. 2, the kiln exhaust gas is mainly compared with the right half area of the exhaust gas passage 3C of the inlet hood 3 having a rectangular cross section. Is a region where the flow velocity is low and stagnation is likely to occur in the exhaust gas flow.

(2) Since the area through which the raw material passes is located near the corner 3B of the wall 3A on the kiln 1 side of the exhaust gas passage 3C, the exhaust gas flow rate is relatively small due to the resistance of the wall and the like. This is the area where the exhaust gas flow stagnates in the area. Due to the above (1) and (2), a phenomenon in which the raw material blown into the exhaust gas passage 3C is swept away by the exhaust gas flow rising in the exhaust gas passage 3C in the inlet hood 3 and carried away is prevented.

(3) The raw material blowing port 30 is
As viewed in a plan view, as shown in FIG.
To the base end of the opening 3a on the side away from the corner 3B,
Since the raw material discharged to the exhaust gas passage 3a from the gas extraction port 3a is attached to the opening of the exhaust gas extraction port 3a, the raw material discharged by the exhaust fan (IDF) 15 of the chlorine bypass 10 causes the raw material exhaust gas extraction port 3a. Since the air flows in a curved manner so as to be drawn substantially to the center of the opening 3a, the air smoothly flows into and is taken into the opening of the bleeding port 3a.

As described above, the raw material is blown into the inlet hood 3 by pneumatic transportation. The blowing speed is such that the blown raw material rides on the flow of the kiln exhaust gas in the exhaust gas passage 3 C in the inlet hood 3. Fast enough to not reach the exhaust gas extraction port 3a after being blown, and not to fall by gravity before reaching the exhaust gas extraction port 3a after being blown. It is desirable that the time from when the raw material is blown into the exhaust gas passage 3C to when the raw material reaches the exhaust gas extraction port 3a be as long as possible in order to ensure the adhesion and condensation of chlorine (chlorine compound).

The raw material blown into the exhaust gas passage 3C in the inlet hood 3 from the raw material blowing port 30 is supplied with KCl as chlorine contained in the high-temperature exhaust gas while being taken into the exhaust gas bleeding port 3a. Alternatively, a gaseous (vapor) chlorine compound such as NaCl touches the surface of the raw material particles at a low temperature and is cooled instantaneously to, for example, about 600 ° C., which is a temperature at which the chlorine compound solidifies through liquefaction. ,
In the course of such cooling, especially when liquefied,
The raw material is easily attached and condensed on the particle surface, and is easily fixed to the raw material. The gaseous chlorine compound is thus easily adhered and condensed on the particle surface of the cement raw material in a short time, that is, fixed.

The exhaust gas extraction port 3 of the inlet foot 3
a part of the kiln exhaust gas and the calcined raw material in which a chlorine compound is adhered and condensed on the surface, and the raw material are part of dust (the lowermost cyclone chute 7 in the inlet hood 3). Along with the calcined raw material, or clinker), from the axial direction into the mixing chamber 11d of the bleed pipe 11 as a cooling means of the chlorine bypass 10 connected and attached to the exhaust gas bleed port 3a. The mixing chamber 1
Within 1d, it is mixed with cooling air supplied from the cooling fan 11a spirally from the tangential direction along the inner wall surface of the outer periphery of the bleeding tube 11 and further cooled, for example, at a temperature of 300 to 3
The temperature is set to 50 ° C., and solidification of the chlorinated product adhering to the surface is finally performed to ensure solidification.

In the mixing chamber 11d, the remaining part of the gaseous chlorine compound that has missed the opportunity to adhere to and condense on the raw material in the exhaust gas passage 3C of the inlet foot 3 is also converted into a solidified chlorine product. In addition, as described above, the cooling air is swirled from the tangential direction to the inner wall surface of the bleeding pipe 11 so that dust or the like is generated on the bleeding pipe 11 itself and the inner surface of a duct constituting the chlorine bypass 10 thereafter. Adhesion and adhesion (coating) are prevented.

After that, the exhaust gas is supplied to the outlet 1 of the bleed pipe 11 together with the calcined raw material, raw material, and a part of dust, on which the chlorine compound (chlorinated solid) as chlorine is adhered and condensed.
It is discharged from 1e and sent to the humidity control tower 13 through the duct 12a, where it is further cooled to a temperature of about 150 ° C. by the sprinkler 13a. As a result, the calcined raw material, the raw material, and the dust to which the chlorine compound has adhered and condensed, the electric resistance value is further reduced, and collection by the downstream electric dust collector 14 is facilitated. A part of the raw material and dust to which the solidified chlorine is attached is taken out from the lower outlet of the humidity control tower 13 and transferred to the dust transport facility 17.

Then, the calcined raw material, the raw material, and the exhaust gas (extracted gas) accompanied with a part of the dust, which have exited the humidity control tower 13 and have the chlorinated product attached thereto, pass through the duct 12b to the electric precipitator 14. be introduced. In this electric dust collector 14,
The calcined raw material to which the chlorine compound is adhered and condensed, the raw material, and the dust extracted together with the exhaust gas are relatively coarse particles and have a low electric resistance value. By being chilled and conditioned at 13
The dust is easily collected and collected by the dust collecting electrode of the electric dust collector, and is separated by being easily dropped into the lower collecting hopper by hammering the electrode plate. In this way, chlorine in the exhaust gas is reliably removed.

The calcined raw material, raw material, and dust, on which the chlorinated solids collected by the electric dust collector 14 and dropped on the lower collecting hopper are adhered and condensed, pass through the discharge port of the collecting hopper and are transported to the dust transport facility. Transferred to 17. Dust transport equipment 17
The calcined raw material, raw material, and the dust, on which the chlorinated solids transferred to and condensed, are sent to the dust storage hopper 18 by the dust transport equipment 17 and stored there, and are appropriately removed by a dust discharge vehicle. Will be issued. The clean gas is discharged from the chimney 16 to the atmosphere via the exhaust fan 15.

According to the present embodiment, in the above-described method for removing chlorine in the exhaust gas of cement kiln by chlorine bypass, the supply (use) ratio of the calcined raw material and the raw material, which are the condensing medium of chlorine, is reduced. , As follows:
That is, the calcined raw material, which is a condensing medium of chlorine, has a temperature of 80
It is a high temperature of 0 to 860 ° C, and the difference from the temperature of the kiln exhaust gas to which it is dispersedly supplied (for example, 950 to 1200 ° C) is smaller than that of a low-temperature raw material (50 to 70 ° C). In view of the fact that the adhesion and condensation of chlorine is not so good for this reason, in the present embodiment, the supply of the chlorine-attached condensation medium into the exhaust gas passage 3C is carried out by dispersing and supplying a high-temperature calcined raw material having poor adhesion and condensation. Is used as much as possible and the amount of raw material having good adhesion and condensation properties is increased.

For example, the amount of the calcined material to be dispersed is minimized by minimizing the amount of the dispersion plate 20 inserted into the chute 7, and the amount of the raw material that compensates for the shortage is supplied to the variable speed rotary feeder of the pneumatic transport device 50. This is executed by changing and adjusting the number of revolutions of the rotor 53 and blowing it. More preferably, the dispersed supply amount of the calcined raw material is set to a winding amount of the calcined raw material that is slightly insufficient for ensuring the performance of the electric dust collector 14, and the blowing amount of the raw material is set to the electric dust collector 1.
Adjustment is made according to the actual dust collection state (dust collection performance) at the time of operation 4. That is, for example, the insertion amount of the dispersion plate 20 is set and fixed to a certain minimum value (an insertion amount that slightly increases the amount of raw material to be required for the required performance of the electrostatic precipitator 14), and is fixed. Minutes should be supplemented with raw materials.

In this manner, the calcined raw material that has consumed energy is not brought into the chlorine bypass 10 without losing the calorific value, and the loss of the calcined raw material is prevented. be able to. And
Dust coating occurs on the inside of the discharge chute 7 of the lowermost cyclone 5a and on the inner wall surface of the exhaust gas passage 10C where the chute 7 is connected, and as a result, the amount of insertion of the dispersion plate 20 into the chute 7 is reduced. Even when it becomes difficult to adjust the amount of dispersion of the calcined raw material in the exhaust gas passage 20C by the adjustment (increase / decrease), that is, the amount of the calcined raw material fluctuates depending on the growth or falling off of the coating. Even in this case, the insertion amount of the dispersion plate 20 is minimized, or
By dispersing and supplying the calcined raw material while minimizing the variation in the amount of dispersion by minimizing the dispersion, a stable and stable chlorine removing action can be achieved.

The removal of chlorine is carried out by winding up and supplying the calcined raw material using the dispersion plate 20, and there is a disadvantage that the dispersion of the calcined raw material varies due to the influence of the coating as described above. The raw material pneumatic transportation device 50 as a raw material supply means is additionally installed in the existing cement kiln equipped with a chlorine bypass (added)
By doing so, an improvement can be achieved so that chlorine can be reliably removed.

In this embodiment, as described above, the amount of the raw cement raw material as a necessary chlorine-condensing and condensing medium is obtained by adhering and condensing a chlorine compound as chlorine from the exhaust gas extraction port 3a to the chlorine bypass 10 and sucking it. Adjustment is made according to the degree of performance requirement of the electric dust collector 14. In this case, the chlorine concentration (weight ratio to chlorine particles) of the particles (calcined raw material, raw material, and accompanying dust) generally sucked from the exhaust gas extraction port 3a is about 3 to 8%. Adjust so that the calcined raw material and raw material are sucked to a certain degree.

The adjustment of the suction amount of the raw material, that is, the adjustment of the amount of the raw material blown into the exhaust gas passage 3C is performed by changing the raw material stored in the small hopper 52 of the raw material air transport device 50 to the variable speed rotary feeder 53. It can be easily performed by changing the rotation speed of the rotor and adjusting the cut-out amount (discharge amount). As described above, the amount of raw material to be blown can be easily adjusted, so that chlorine can be reliably removed.

In the present embodiment, by using both the calcined raw material and the raw material as the chlorine-condensed condensing medium, the capacity of the raw material pneumatic transport device 50 can be reduced as compared with the case where all of the adhered condensing medium is replaced with the raw material. For example, the air volume and pressure of the blower 56, the diameter of the transport pipe 55, and the diameter of the acceleration pipe 54 may be small.

In the above embodiment, the case where the raw material is supplied to the inside of the exhaust gas passage at the bottom of the kiln kiln by blowing it toward the exhaust gas extraction port has been described. The raw material may be supplied from an appropriate position into the inside of the exhaust gas passage of the kiln kiln without being limited to supplying the raw material by blowing.

That is, for example, the exhaust gas extraction port 3a is lower than the exhaust gas extraction port 3a of the inlet hood 3, which is the exhaust gas passage of the kiln kiln kiln, that is, upstream of the exhaust gas extraction port 3a. Is supplied to the inside of the exhaust gas passage 3C by gravity through a rotary feeder or the like from a chute attached to the wall surface 3A located on the same kiln side, and is put on the kiln exhaust gas flow from the feeding point to the upper part of the kiln exhaust gas flow. The raw material to which the chlorine compound is adhered and condensed to the raw material may be sucked from the exhaust gas extraction port 3a while the chlorine compound in the exhaust gas is adhered and condensed to the raw material.

In the above embodiment, the exhaust gas bleeding port 3a and the raw material blowing port 30 are connected to each other as shown in FIG.
A case is shown in which the wall is attached to the kiln side wall 3A of a rectangular cross section of the rising portion of the entrance hood 3 and the wall intersecting the wall 3A at positions close to the corners 3B of both the walls. However, since the exhaust gas flow rate and the stagnation portion of the exhaust gas are not uniform depending on the specifications of the shape and size of the inlet hood of the kiln, the mounting position and the blowing speed of the exhaust gas extraction port 3a and the raw material blowing port 30 are respectively different. According to the actual condition of the kiln and the design specifications, it is determined that the raw material is to be blown into a region where the upward flow of the exhaust gas is stagnant, that is, a region with a low flow velocity.

In the above embodiment, the raw material injection port 30 is opened at a height almost at the intermediate position of the exhaust gas extraction port 3a. However, as shown by a broken line in FIG. Instead of the port 30, the blowing port 30a may be provided at a position lower than a substantially middle position of the opening of the exhaust gas extraction port 3a. When opened at this position, even if the raw material blown into the exhaust gas passage 30C rises under the influence of the exhaust gas ascending flow, the opening of the exhaust gas extraction port 3a is located above the injection point. It becomes easy to be sucked into 3a.

In the above embodiment, a cement kiln in which the calciner 5b is attached to the suspension preheater 5 has been described. However, the present invention can be applied to a cement kiln with a suspension preheater without a calciner. In this case, the lowermost cyclone 5
The raw material as a chlorine-adhered condensing medium supplied from a to the exhaust gas passage 3C through the chute 7 may be a raw material preheated in each cyclone of the suspension preheater, that is, a preheated raw material.

[0088]

As is apparent from the above description, the present invention has the following excellent effects.

In the first or ninth aspect of the present invention, the degree of adhesion and condensation of chlorine is adjusted so as to compensate for the shortage of the degree of adhesion and condensation of chlorine due to a preheating / calcination raw material having poor adhesion and condensation. By adjusting the supply amount of good raw material to the exhaust gas passage, it is possible to adjust the supply rate, so that the supply ratio is adjusted and chlorine is attached to the surface and condensed. By removing the preheated / calcined raw material and the raw material, which are the adhered condensing medium, by a dust collector such as an electric dust collector by chlorine bypass, it is possible to reliably remove chlorine contained in the kiln exhaust gas.

Further, for example, due to the coating of dust on the inside of the discharge chute of the lowermost cyclone and the inner wall surface of the exhaust gas passage at the portion to which the chute is connected, the preheating / temporary control by adjusting the insertion amount of the dispersion supply means is performed. Even if the dispersion amount of the calcined material is dispersed in the exhaust gas passage and the adjustment of the dispersed amount becomes uncertain, for example, the dispersion amount of the preheating / calcining material is minimized by minimizing the insertion amount of the dispersion supply means. So that the raw material supply is performed stably,
To compensate for the increase, by increasing the supply amount of raw material having a good adhesion and condensation property of chlorine, it is possible to surely remove chlorine.

By reducing the amount of the preheated / calcined raw material, the amount of the preheated / calcined raw material carried to the chlorine bypass is reduced as a result. Can be suppressed to a small amount.

[0092] From the above, the removal of chlorine is dispersed in the cement kiln (cement firing apparatus) provided with the existing chlorine bypass using the dispersing and supplying means in which the dispersion amount varies and the dispersion amount cannot be adjusted smoothly. By additionally providing the raw material supply means, it is possible to easily improve the chlorine removal rate.

[0093] The preheating and
Since the calcined raw material and the raw material are used in combination, compared to replacing all of the attached condensed medium with the raw material, the capacity of, for example, a pneumatic transport device as a raw material transport device, for example, the air volume and pressure of a blower, the transport pipe and The diameter of the accelerating tube 54 can be small.

According to the second or tenth aspect of the present invention, the raw material is supplied to the exhaust gas passage of the kiln kiln by blowing it from the raw material injection port to the exhaust gas extraction port opened in the exhaust gas path by an air transport device. Therefore, the raw material is blown into the exhaust gas passage at a predetermined pressure toward the exhaust gas extraction port. For this reason, the raw material on which the chlorine compound is adhered and condensed on the surface is more reliably taken into the exhaust gas extraction port without flowing into the exhaust gas flow, and the chlorine compound is adhered and condensed on the surface by the dust collecting means in the chlorine bypass. Dust collection of raw materials,
That is, chlorine is reliably removed.

Further, as described above, the raw material blown into the exhaust gas passage can be more surely sucked into the exhaust gas extraction port, so that the amount of the raw material scattered or carried away by the exhaust gas can be reduced. Is economical without consuming raw materials unnecessarily,
The raw material transporting equipment has a small capacity, and the equipment does not need to be large.

According to the third aspect of the present invention, the temperature difference between the raw material and the exhaust gas in the exhaust gas passage to which the raw material is supplied is large, so that the temperature of the gaseous chlorine compound can be reduced more reliably. Thereby, it is possible to reliably carry out the adhesion and condensation on the raw material particle surface in the process of changing the state of liquefaction and solidification due to the temperature drop. Therefore, the temperature of the exhaust gas is low and the adhesion and condensation property (degree) of chlorine is not good. Can be performed reliably.

In the structure of claim 4 or 12, a part of the raw cement raw material originally supplied to the suspension preheater of the cement kiln is extracted and used as a medium for removing chlorine, so that it is necessary to separately prepare a medium for removing chlorine. Therefore, the present invention can be easily implemented. And
In the configuration of the apparatus according to the twelfth aspect, the raw material stored in the raw material hopper is adjusted by changing the rotation speed of the variable speed rotary feeder so that the cutout amount (discharge amount) can be adjusted and the transport amount of the raw material can be adjusted, The amount of raw material blown into the exhaust gas passage can be adjusted.

This makes it possible to easily adjust the degree of attachment and condensation of the chlorine compound by the raw material, and to adjust the amount of the preheated / calcined raw material supplied to the exhaust gas passage by adjusting the insertion amount of the dispersed supply means, and It is possible to compensate for the uncertainty in the adjustment of the amount of dispersion of the preheating / calcining raw material by the dispersion supply means, thereby making it possible to compensate for the chlorine removal. Can be performed.

In the structure of the fifth, sixth or eleventh aspect, the raw material is blown into the exhaust gas passage in a region where the flow rate of the exhaust gas is low, such as a portion where the flow of the exhaust gas in the exhaust gas passage is stagnant. For example, the injection of raw material into the exhaust gas passage,
Toward the exhaust gas extraction port opened to the corner of the exhaust gas passage on the side wall located on the kiln side of the exhaust gas passage, a position close to the corner of the side wall where the exhaust gas extraction port intersects with the opened sidewall. This is performed from a raw material blowing port provided in the apparatus. Therefore, the phenomenon in which the raw material blown into the exhaust gas passage is swept away by the exhaust gas flow and carried away can be prevented. For this reason, chlorine removal is performed more reliably.

According to the structure of the seventh aspect, the uncertainty of the amount of dispersion by the means for dispersing and supplying the preheated / calcined raw material is eliminated as much as possible, and the shortfall is eliminated by using a raw material having good chlorine adhesion and condensation properties. , It is possible to surely remove chlorine. Further, the amount of heat that is lost when the preheated / calcined raw material is removed by the chlorine bypass and the amount of the preheated / calcined raw material can be minimized.

According to the eighth aspect of the present invention, the amount of raw material to be blown is increased or decreased according to the actual dust collection state (collection performance) during the operation of the electric precipitator, so that control for reliable chlorine removal is performed. It can be done easily.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of one embodiment of a cement kiln kiln bottom according to an apparatus for removing chlorine in exhaust gas from a cement kiln by chlorine bypass according to the present invention.

FIG. 2 is a plan view cut along the line AA of FIG. 1, showing a positional relationship between a raw material blowing port and an exhaust gas extracting port.

FIG. 3 is a system diagram of an embodiment of a raw cement air transport device of the present invention.

FIG. 4 is a system diagram of a cement kiln (sintering device) having a chlorine bypass.

FIG. 5 is a schematic vertical sectional view of a bottom part of a kiln for a cement kiln according to a conventional apparatus for removing chlorine from exhaust gas from a cement kiln by chlorine bypass.

FIG. 6 is a side view taken along line B in FIG. 1 or FIG. 5, and is a view showing a mounting state of a dispersion plate (dispersion supply means).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Kiln 2 Clinker cooler 3 Kiln inlet hood 3a Exhaust gas extraction port 3A Inlet hood kiln side wall surface 3B Inlet hood corner 3C Exhaust gas passage 4 Rising duct 5 Suspension preheater 5a Bottom cyclone 5b Calciner 5c Raw material supply pipe 7 Bottom cyclone Chute 7a Calcination raw material supply opening 10 Chlorine bypass 11 Exhaust gas extraction pipe 11a Cooling fan 11c Cooling air inlet 11d Mixing chamber 11e Exhaust gas outlet 12 Duct 13 Humidity control tower 14 Electric dust collector 15 Exhaust (attraction) fan 20 Calcination raw material dispersion plate (dispersion) Supply means) 30 Raw material injection port 40 Raw material transport device for kiln 50 Raw material air transport device for chlorine bypass 52 Small hopper (raw material hopper) 53 Variable speed rotary feeder 54 Accelerator tube 55 Raw material transport tube 56 Blower

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F27B 7/20 F27D 17/00 104G F27D 17/00 104 105G B01D 53/34 134A 105 ZAB

Claims (12)

[Claims] 1. A preheated and / or calcined raw material collected in a lower stage cyclone of a preheater is dispersed and supplied into a high temperature kiln exhaust gas in an exhaust gas passage of a kiln kiln, and chlorine is adhered and condensed to the raw material. The raw material to which chlorine was adhered and condensed was extracted together with part of the kiln exhaust gas from the exhaust gas extraction port of the exhaust gas passage at the bottom of the kiln kiln to a chlorine bypass, and the exhaust gas was cooled by the chlorine bypass to be adhered and condensed to the raw material. Cement kiln exhaust gas by chlorine bypass in which chlorine is cooled and solidified to form a chlorinated product, and the raw material on which the chlorinated material is adhered and condensed is collected and removed by a chlorine bypass to remove chlorine in the exhaust gas of the cement kiln. In the method for removing chlorine in the waste gas, a low-temperature cement raw material is supplied into the kiln high-temperature exhaust gas in the exhaust gas passage to thereby remove the exhaust gas. Wherein chlorine is adhered and condensed to the raw material in the high temperature exhaust gas of the passage, and the raw material on which the chlorine is adhered and condensed is also extracted from the exhaust gas extraction port to the chlorine bypass together with the kiln exhaust gas. How to remove chlorine in kiln exhaust gas. 2. A method according to claim 1, wherein the raw material is supplied to the exhaust gas in the exhaust gas passage by blowing the raw material into the exhaust gas extraction port. How to remove chlorine. 3. The preheated and / or calcined raw material supplied to the exhaust gas passage is at a temperature of 800 to 860 ° C., the raw material is at a temperature of 50 to 70 ° C., and the exhaust gas of the exhaust gas passage is The method for removing chlorine from exhaust gas of cement kiln by chlorine bypass according to claim 1 or 2, wherein the temperature is 950 to 1200 ° C. 4. A cement kiln exhaust gas by chlorine bypass according to claim 1, wherein a part of the raw material fed into the preheater is used as the raw material supplied to the exhaust gas passage. How to remove chlorine from inside. 5. The method according to claim 5, wherein the raw material is blown into the exhaust gas passage toward the exhaust gas extraction port in a region where the flow of exhaust gas in the exhaust gas passage is low, such as a portion where the flow of exhaust gas is stagnant. The method for removing chlorine in exhaust gas of a cement kiln by the chlorine bypass according to claim 2, 3, or 4. 6. The raw material is blown into the exhaust gas passage toward the exhaust gas extraction port, which is opened on a side wall located on the kiln side of the exhaust gas passage toward a corner of the exhaust gas passage. 6. The method for removing chlorine in exhaust gas from a cement kiln by a chlorine bypass according to claim 5, wherein the method is performed from a position near the corner of the side wall intersecting the side wall where the exhaust gas extraction port is opened. 7. The amount of the preheated and / or calcined raw material dispersed and supplied into the high temperature kiln exhaust gas in the exhaust gas passage is minimized, and the raw material is supplied in such an amount as to make up for the shortage. The method for removing chlorine from cement kiln exhaust gas by chlorine bypass according to claim 2, 3, 4, 5, or 6, wherein the gas is blown toward the exhaust gas extraction port. 8. The dispersed supply amount of the preheated and / or calcined raw material is set to an amount that is slightly insufficient to ensure the performance of the electric dust collector as a dust collector, and the blowing amount of the raw material is set to a value of the electric dust collector. The method for removing chlorine in exhaust gas of a cement kiln by a chlorine bypass according to claim 7, wherein the method is adjusted according to a dust situation. 9. The preheated and / or calcined raw material collected in the lowermost cyclone of the preheater is introduced into the high temperature kiln exhaust gas in the exhaust gas passage at the bottom of the kiln kiln via a discharge chute connected to the lower part of the cyclone. Then, the amount of insertion into the inside of the chute is made to collide with the dispersing and supplying means which is attached in an adjustable manner, and is dispersed and supplied by the exhaust gas. The raw material was extracted from the exhaust gas extraction port of the exhaust gas passage of the kiln kiln with a portion of the kiln exhaust gas to a chlorine bypass, and the exhaust gas was cooled by cooling means to cool and solidify the chlorine adhered and condensed on the raw material. Chlorine in the exhaust gas of the cement kiln is removed by collecting and removing the raw material on which the chlorinated product is adhered and condensed by dust collecting means. In a device for removing chlorine from exhaust gas of a cement kiln by chlorine bypass, a raw material supply means for supplying a low-temperature cement raw material is installed in the exhaust gas passage at the bottom of the kiln kiln. An apparatus for removing chlorine from a cement kiln exhaust gas by a chlorine bypass, wherein chlorine is adhered and condensed to the raw material, and the raw material on which the chlorine is adhered and condensed is extracted together with the kiln exhaust gas from the exhaust gas extraction port to a chlorine bypass. 10. The raw material supply means includes: a raw material injection port which is opened toward the exhaust gas extraction port in a high temperature exhaust gas passage of a kiln kiln; and a raw material connected to the raw material injection port. 10. A pneumatic transportation device.
For removing chlorine from cement kiln exhaust gas by chlorine bypass. 11. The exhaust gas extraction port is provided to be opened at a position close to a corner of a side wall on the kiln side at a rising portion of an exhaust gas passage of a kiln kiln, and the raw material injection port is provided by the exhaust gas extraction port. The apparatus for removing chlorine from a cement kiln exhaust gas by a chlorine bypass according to claim 10, wherein the apparatus is provided at a position closer to the corner of a side wall intersecting with the provided side wall. 12. A raw material pneumatic transport device comprising: a raw material hopper to which a part of raw material is supplied from the middle of a cement raw material transport path for a preheater; 11. An accelerating pipe connected via a rotary feeder, a raw material transport pipe for communicating the accelerating pipe with the raw material inlet, and a blower connected to the accelerating pipe. Or a device for removing chlorine from cement kiln exhaust gas by means of a chlorine bypass of item 11.