CN117225123A - Cement kiln chlorine removal system and chlorine removal method - Google Patents

Abstract

The application discloses a kiln tail waste gas dechlorination method, which is used for dechlorinating a cement kiln and comprises the following steps: firstly, extracting waste gas of a kiln tail smoke chamber (10), and conveying the waste gas to a high-temperature cyclone (2) under the condition of sealing and heat preservation; step two, after being treated by a high-temperature cyclone (2), coarse dust particles enter a decomposing furnace, and high-temperature gas is conveyed to a cold and hot air exchanger; thirdly, cooling the high-temperature gas through a cold and hot air exchanger, and crystallizing the cooled chloride ions on the surface of the dust; and fourthly, collecting dust with chloridion attached to the surface through a bag type dust collector (4), and enabling the filtered gas to enter an exhaust gas treatment system (6). The method for removing chlorine from the kiln tail waste gas can realize high-efficiency chlorine removal.

Description

Cement kiln chlorine removal system and chlorine removal method

Technical Field

The application relates to the field of cement production, in particular to a cement kiln chlorine removal system and a chlorine removal method.

Background

When various solid dangerous wastes or combustible wastes are used as alternative fuels, more or less elements such as potassium, sodium, sulfur, chlorine and the like can be brought into the rotary kiln system, the elements can volatilize at high temperature and condense at low temperature after passing through the rotary kiln system, enrichment is finally generated, the atmosphere of the kiln system is changed, and when the atmosphere of the kiln system is serious, the skinning and the blockage in the rotary kiln system can be caused, the whole thermodynamic system is disturbed, the normal operation of the cement kiln system is influenced, and simultaneously, a large amount of elements such as potassium, sodium, sulfur, chlorine and the like can be solidified into clinker, so that the quality of the cement clinker is influenced, and therefore, the rotary kiln system needs to be subjected to chlorine removal treatment.

The flow of the existing chlorine removal system is as follows: extracting a certain amount of high-temperature air (about 1050 ℃) from a kiln tail smoke chamber through a circular air extracting device, immediately cooling the high-temperature air through a dilution fan to ensure that the temperature of the high-temperature air is about 400 ℃, and at the moment, the temperature is far lower than the chloride ion gasification temperature (Cl < - > is completely gasified or the decomposition temperature is more than or equal to 950 ℃, the gas-solid coexisting temperature is 850-950 ℃ and the complete solidification temperature is less than or equal to 850 ℃), so that chloride ions in the flue gas can be changed into solid phase from gas phase and condensed into powder of the flue gas; then the cooled high-temperature flue gas enters a cyclone barrel to carry out gas-solid separation, and as a certain amount of particles less than 10um are difficult to collect in the solid phase, the particles less than 10um enter the next working procedure along with the flue gas, and coarse particles are collected and returned to the decomposing furnace again; the separated flue gas enters an air cooler to exchange heat and reduce the temperature to 180 ℃, enters an exhaust gas treatment system after being dedusted by a bag dust collector, and the collected ash is stored to achieve a certain amount and then is subjected to harmless treatment.

In the working process of the chlorine removal system, the high-temperature waste of the kiln tail smoke chamber is immediately mixed with cold air for dilution, the temperature of the kiln tail smoke chamber is rapidly reduced to below 400 ℃, and along with the process of reducing the temperature of gas, a large amount of harmful components in the kiln tail waste are condensed in dust, after being collected by the cyclone, the condensed coarse particles are collected and then enter the decomposing furnace again, and the chloride ions contained in the coarse particles are also more, and finally the content of the chloride ions discharged out of the rotary kiln system is relatively less, so that the chlorine removal effect of the conventional chlorine removal system is not obvious.

Disclosure of Invention

The application aims to provide a cement kiln chlorine removal system and a chlorine removal method, and the kiln tail waste gas chlorine removal method can realize high-efficiency chlorine removal.

In order to achieve the above object, the present application provides a method for removing chlorine from kiln tail gas, for removing chlorine from cement kiln, the method comprising:

firstly, extracting waste gas of a kiln tail smoke chamber, and conveying the waste gas to a high-temperature cyclone under the condition of sealing and heat preservation;

step two, after being treated by a high-temperature cyclone, coarse dust particles enter a decomposing furnace, and high-temperature gas is conveyed to a cold and hot air exchanger;

thirdly, cooling the high-temperature gas through a cold and hot air exchanger, and crystallizing the cooled chloride ions on the surface of the dust;

and fourthly, collecting dust with chloridion attached to the surface through a bag type dust collector, and enabling the filtered gas to enter an exhaust gas treatment system.

Preferably, the temperature of the gas entering the high temperature cyclone is not lower than 950 ℃.

Preferably, the temperature of the gas is not higher than 400 ℃ after the temperature is reduced by the cold-hot air exchanger.

The application also provides a cement kiln chlorine removal system for performing chlorine removal operation by adopting the kiln tail waste gas chlorine removal method, wherein the cement kiln chlorine removal system comprises an air taking device, a high-temperature cyclone, a cold and hot air exchanger and a bag type dust collector which are sequentially connected, and an inlet of the air taking device is connected into a kiln tail smoke chamber and extracts waste gas from the kiln tail smoke chamber;

the cold and hot air exchanger comprises a cold air extraction device and a cold and hot air interaction bin connected with the cold air extraction device, an outlet of the high-temperature cyclone is connected to the cold and hot air interaction bin, and high-temperature air and cold air extracted by the cold air extraction device are subjected to heat exchange in the cold and hot air interaction bin;

and the pipeline between the air taking device and the high-temperature cyclone cylinder is subjected to heat preservation treatment.

Preferably, the inlet end of the wind taking device is provided with a duckbill wind taking opening, and the width of the duckbill wind taking opening gradually decreases from front to back.

Preferably, the height of the duckbill type air taking opening is H, and H is not more than 1.2m.

Preferably, the width of the widest part of the duckbill type air taking opening is L, and 4H is more than or equal to L and more than or equal to 3H.

Preferably, the air taking device, the high-temperature cyclone and the heat preservation air pipe are arranged into an integrated heat preservation structure.

Preferably, a connecting section is further arranged between the duckbill type air taking opening and the heat preservation air pipe, and the duckbill type air taking opening is connected with the heat preservation air pipe through the connecting section.

According to the technical scheme, under the high temperature state, the high temperature cyclone filters high temperature gas, and because the temperature of the high temperature gas is higher than the condensation point of chloride ions, the chloride ions exist in the flue gas in a gas phase, so that the amount of the chloride ions attached to coarse particles is reduced, more chloride ions flow to the bag type dust collector in the gas phase state, a cold and hot air exchanger for cooling the gas is arranged in front of the bag type dust collector, and after the gas is cooled by the cold and hot air exchanger, the chloride ions are condensed and attached to the surfaces of fine particles and finally collected by the bag type dust collector together with the fine particles. In this way, the present application achieves efficient treatment of chloride ions.

Additional features and advantages of the application will be set forth in the detailed description which follows.

Drawings

The accompanying drawings are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification, illustrate the application and together with the description serve to explain, without limitation, the application. In the drawings:

FIG. 1 is a schematic diagram of the operation of a cement kiln chlorine removal system;

FIG. 2 is a cross-sectional view of a duckbill air intake;

FIG. 3 is a bottom view of a duckbill air intake;

fig. 4 is a left side view of a duckbill air intake.

Description of the reference numerals

1 duckbill type air intake 2 high temperature cyclone

31 cold air extraction device 4 bag type dust collector

12 heat preservation tuber pipe 11 linkage segment

32 cold and hot air interaction bin 5 steel plate bin

Waste gas treatment system for 10 kiln tail smoke chamber 6

Detailed Description

The following describes specific embodiments of the present application in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the application, are not intended to limit the application.

In the present application, unless otherwise indicated, directional terms such as "front, rear, inner" and the like are merely used to denote the orientation of the term in a conventional use state or are commonly understood by those skilled in the art, and should not be construed as limiting the term.

A kiln tail waste gas dechlorination method for dechlorinating a cement kiln, the dechlorination method comprising:

firstly, extracting waste gas of a kiln tail smoke chamber 10, and conveying the waste gas to a high-temperature cyclone cylinder 2 under the condition of sealing and heat preservation;

step two, after being treated by the high-temperature cyclone tube 2, coarse dust particles enter a decomposing furnace, and high-temperature gas is conveyed to a cold and hot air exchanger;

thirdly, cooling the high-temperature gas through a cold and hot air exchanger, and crystallizing the cooled chloride ions on the surface of the dust;

fourth, collecting the dust with chloride ions attached to the surface through a bag type dust collector 4, and enabling the filtered gas to enter an exhaust gas treatment system 6.

Through implementation of the above technical scheme, under the high temperature state, the high temperature cyclone 2 filters the high temperature gas, and because the temperature of the high temperature gas is higher than the condensation point of chloride ions at this time, the chloride ions exist in the flue gas in the gas phase, so that the amount of the chloride ions attached to the coarse particles is reduced, more chloride ions flow to the bag type dust collector 4 in the gas phase state, a cold and hot air exchanger for cooling the gas is arranged in front of the bag type dust collector, and after the gas is cooled by the cold and hot air exchanger, the chloride ions are condensed and attached to the surfaces of the fine particles and finally collected by the bag type dust collector 4. In this way, an efficient treatment of chloride ions is achieved.

The waste gas in the kiln tail smoke chamber 10 is conveyed to the high-temperature cyclone cylinder 2 under the condition of sealing and heat preservation, the temperature of the gas in the kiln tail smoke chamber 10 is about 1050 ℃, the temperature of the gas extracted from the kiln tail smoke chamber 10 can be maintained at about 1000 ℃ after heat preservation and sealing treatment, and the temperature is higher than the condensation temperature of chloride ions, so that the chloride ions in the high-temperature gas can hardly be condensed and still exist in the high-temperature flue gas in a gas phase state, and coarse particles larger than 10um are separated by the high-temperature cyclone cylinder 2 after passing through the high-temperature cyclone cylinder 2 and are used as dust materials, and the dust materials are raw materials for firing clinker and are conveyed back into the decomposing furnace.

The gas entering the high-temperature cyclone cylinder 2 is subjected to sealing heat preservation treatment, so that chloride ions contained in the gas are not condensed on the surface of the dust material, and the return of the chloride ions to the decomposing furnace is avoided.

After leaving the high temperature cyclone 2, chloride ions still exist in the high temperature gas in a gas phase state, the high temperature gas is cooled in the cold and hot air exchanger, and the chloride ions in the gas are condensed and attached to small-particle dust and finally collected by the bag type dust collector 4.

The chloride ions are adhered to the dust and collected by the dust collecting bag, and harmless treatment can be carried out after the quantity of the dust reaches a certain quantity. The gas filtered by the bag type dust collector 4 enters the waste gas treatment system 6 through a pipeline for the next treatment.

In this embodiment, it is preferable that the temperature of the gas entering the high temperature cyclone 2 is not lower than 950 ℃.

The temperature at which the chloride ions are completely gasified or decomposed needs to be not lower than 950 ℃, and in order to ensure that the coarse particles separated from the high-temperature cyclone 2 contain as little chloride ions as possible, it is necessary to ensure that the gas temperature in the high-temperature cyclone 2 is higher than 950 ℃ so that the chloride ions can exist in the gas in a gas phase state without condensation and adhesion to the coarse particles and be sent back to the decomposing furnace.

The more chloride ions exist in the gas phase state, the less chloride ions are attached to coarse particles correspondingly, and therefore, the higher the gas temperature in the high-temperature cyclone 2 is, the more beneficial to the chlorine removal of the system.

In this embodiment, it is preferable that the gas temperature is not higher than 400 ℃ after the cooling by the cold and hot air exchanger.

Although the complete solidification temperature of the chloride ions needs not to be more than 850 ℃, a large amount of chloride ions needs to be condensed, and as the temperature is reduced, the speed of the chloride ion condensation is correspondingly increased, so that the chloride ions can be condensed at a faster speed in the process of reducing the gas temperature by reducing the gas temperature in the cold and hot air exchanger, and the cross-sectional area of the cold and hot air exchange chamber 32 is suddenly increased by intersecting the cross-sectional area of the air pipe, so that the flow rate of the gas is reduced after entering the cold and hot air exchange chamber 32, so that the chloride ions have more condensation time before being filtered.

By designing the cross section of the cold and hot air interaction bin 32 to be large enough, the power of the cold air extraction device 31 is set to be large enough to provide enough condensing time for chloride ions, so that all chloride ions can be condensed and attached to the surfaces of fine particles finally in the cold and hot air interaction bin 32.

Referring to fig. 1, the cement kiln chlorine removal system comprises a wind taking device, a high-temperature cyclone 2, a cold and hot wind exchanger and a bag type dust collector 4 which are sequentially connected, wherein an inlet of the wind taking device is connected into a kiln tail smoke chamber 10 and exhaust gas is extracted from the kiln tail smoke chamber 10;

the cold and hot air exchanger comprises a cold air extraction device 31 and a cold and hot air interaction bin 32 connected with the cold air extraction device 31, the outlet of the high-temperature cyclone 2 is connected to the cold and hot air interaction bin 32, and the high-temperature air and the cold air extracted by the cold air extraction device 31 are subjected to heat exchange in the cold and hot air interaction bin 32;

the pipeline between the wind taking device and the high-temperature cyclone cylinder 2 is subjected to heat preservation treatment.

Through implementation of the technical scheme, the temperature in the kiln tail smoke chamber 10 is about 1050 degrees, the air taking device extracts waste gas in the kiln tail smoke chamber 10 and conveys the waste gas into the high-temperature cyclone cylinder 2 through the heat preservation air pipe 12, the temperature of the high-temperature gas cannot be changed obviously under the action of the heat preservation air pipe 12, most of chloride ions exist in smoke in a gas phase state, the high-temperature cyclone cylinder 2 separates coarse particles in the high-temperature gas from the gas, and as the separation is carried out in a high-temperature state, the chloride ions are not condensed, namely the content of the chloride ions in the coarse particles is reduced, the coarse particles finally return to the decomposing furnace, and the chlorine removal system of the cement kiln reduces the amount of the chloride ions returned to the cement kiln system by reducing the amount of the chloride ions attached to the surface of the coarse particles.

After being treated by the high-temperature cyclone 2, the high-temperature gas enters a cold and hot air exchanger through an air pipe, and the temperature is reduced through heat exchange. After the temperature of the gas is reduced, chloride ions in the gas phase are condensed and attached to the surfaces of the fine particles, the fine particles with the diameters smaller than 10um are reserved in a dust collection bag after passing through the bag type dust collector 4, the fine particles obtained by filtration are stored for harmless treatment after reaching a certain amount, and the gas enters the waste gas treatment system 6 after being filtered.

After coarse particles are separated from the high-temperature cyclone cylinder 2 and sent into a decomposing furnace, the flue gas entering the bag type dust collector 4 needs to be cooled, so that chloride ions in the flue gas can be attached to fine particles in the cooling and condensing process and are filtered and collected by the bag type dust collector 4, and the chlorine removal operation of a cement production system is realized.

One embodiment is that an air cooling mode is adopted, the cold air extraction device 31 extracts natural air, the natural air is sent into the cold and hot air interaction bin 32, heat exchange is carried out in the cold and hot air interaction bin 32 through the natural air and high-temperature air, the cooling effect on the air is achieved, and the throughput of the high-temperature air is fixed, so that the supply amount of the cooling air can be changed by increasing the power of the cold air extraction device 31, the supply amount of the cooling air is increased, and a better cooling effect can be achieved.

Another preferred embodiment is that the natural wind and the high temperature gas are mixed in the cold and hot wind interaction chamber 32, which enables the natural wind and the high temperature gas to be more fully contacted, and the cooling efficiency of the cold and hot wind exchange can be improved. When the power of the cool air extracting device 31 is constant, the temperature of the high-temperature gas can be minimized by adopting the cooling method.

In this embodiment, preferably, the inlet end of the wind-taking device is provided with a duckbill type wind-taking port 1 as shown in fig. 2 to 4, the height of the opening of the duckbill type wind-taking port 1 is constant, and the width of the opening of the duckbill type wind-taking port 1 is gradually reduced from front to back.

An exhaust device is further arranged in the cement kiln dechlorination system, and quantitative extraction of kiln tail smoke is achieved through the exhaust device. Under the condition that the power of the air draft device is unchanged, the amount of smoke extracted by the duckbill type air extracting port 1 is fixed, and the opening of the duckbill type air extracting port 1 arranged in the kiln tail smoke chamber is wider so as to increase the area of the air extracting port and further reduce the gas speed when the kiln tail smoke is extracted.

Because the flue gas in the kiln tail flue gas chamber comprises gas and dust, the duckbill type air taking port 1 can be prevented from sucking more dust by reducing the gas speed when the kiln tail flue gas is extracted. These dusts are raw materials for firing clinker, and thus increasing the opening width of the duckbill type air taking port 1 in the kiln tail flue gas chamber is advantageous in reducing the loss of materials.

In this embodiment, preferably, the duckbill type tuyere 1 has a height H of the opening of not more than 1.2m.

In different decomposing furnaces, the kiln tail flue gas chamber has a region with low dust concentration, the position and the height of the region in different equipment are slightly not passed, and the height of the region is about 1-1.5 m as a whole. The duckbill type air taking port 1 is arranged at a position with lower dust concentration in the kiln tail smoke chamber, and the smoke is extracted at the position, so that the dust in the kiln tail smoke chamber can be extracted in a smaller amount, and the loss of materials is reduced.

Preferably, the height of the opening of the duckbill type air taking opening 1 is not more than 1.2m, so that the duckbill type air taking opening 1 is reasonably arranged in a kiln tail smoke chamber, and more dust is prevented from being extracted when the duckbill type air taking opening 1 works.

In this embodiment, preferably, L is set to a width of 4 H.gtoreq.L.gtoreq.3H at the widest part of the opening of the duckbill type air outlet 1.

The width of the widest part of the opening of the duckbill type air taking opening 1 is set to be 3-4 times of the height of the opening, so that the duckbill type air taking opening 1 can obtain better air flowing effect under the condition of increasing the air taking area and can be more effectively matched with an air draft device arranged in a cement kiln chlorine removal system.

In one embodiment, the duckbill air outlet 1 has an L set to 280mm and an H set to 800mm. The duckbill type air taking port 1 is adopted, so that the air speed of an inlet is reduced to below 5m/s, and compared with the duckbill type air taking port 1, the air speed of an air taking pipe of a common circular pipeline (with the diameter of H) is generally 15-18 m/s. Therefore, the duckbill type air taking port 1 has the effect of obviously reducing the air speed.

In this embodiment, the wind extraction device, the high temperature cyclone 2 and the heat preservation wind pipe 12 are preferably provided as an integrated heat preservation structure.

In order to ensure the heat preservation effect before the air taking device reaches the high-temperature cyclone cylinder 2, the air taking device, the high-temperature cyclone cylinder 2 and the heat preservation air pipe 12 can be arranged into an integrated heat preservation structure. Specifically, firstly, the air taking device, the high-temperature cyclone cylinder 2 and the heat preservation air pipe 12 are manufactured and molded by steel materials respectively, then all parts are connected and molded in sequence by welding, then a silicon-calcium plate is paved in the welding molded equipment, the silicon-calcium plate is fixed to the equipment by rivets, and finally, a casting material is cast to form a high-temperature resistant protective layer in the equipment.

Through setting up wind device, high temperature whirlwind section of thick bamboo 2 and heat preservation tuber pipe 12 as an organic whole structure, the heat preservation of continuous casting not only has the heat preservation effect, but also can play sealed effect.

When the air taking device, the high-temperature cyclone cylinder 2 and the heat preservation air pipe 12 are subjected to sealing heat preservation treatment, the heat preservation effect of the system can be improved by increasing the thickness of the heat preservation material, so that the temperature of air in the high-temperature cyclone cylinder 2 can be increased.

The temperature of the gas pumped by the kiln tail smoke chamber of the air taking device is about 1050 ℃, and under the condition of strict heat preservation and leakage prevention, the temperature of the high-temperature gas can still be kept at about 1000 ℃ when the high-temperature gas enters the high-temperature cyclone cylinder 2.

In this embodiment, preferably, a connection section 11 is further provided between the duckbill-type air intake 1 and the heat-preserving duct 12, and the duckbill-type air intake 1 is connected with the heat-preserving duct 12 through the connection section 11.

The cross section of the heat preservation air pipe 12 is circular, the cross section of the duckbill air taking opening 1 is rectangular, the connecting section 11 is arranged as a transition part between the heat preservation air pipe 12 and the duckbill air taking opening 1, the square rounding effect is achieved, the transition between the heat preservation air pipe 12 and the duckbill air taking opening 1 is smoother, and the smooth flow of gas in the air taking opening is facilitated.

The setting of the connecting section 11 is not only beneficial to the stable flow of gas, but also can make the equipment setting and the manufacturing more convenient, the square rounding treatment of the connecting section 11 makes the casting of the heat insulation material at the connecting position more convenient, and the casting effect is also more reliable.

Table 1 shows that the working effect of the chlorine removal system of the cement kiln of the application is obviously improved by comparing the working effect of the chlorine removal system of the cement kiln of the application without adding the high-temperature cyclone cylinder 2 and without carrying out heat preservation and sealing treatment on the gas pumped out from the smoke chamber of the kiln tail.

Table 1:

in Table 1, the temperature of the gas in the high temperature cyclone is 400-450 ℃ and the concentration of chloride ions in the filtered coarse particles is 4.5 after the cyclone is used for treating the gas which is not added with the high temperature cyclone 2 and is not extracted from the kiln tail smoke chamber, the concentration of chloride ions in the fine particles obtained by filtering the coarse particles through the bag type dust collector 4 is 7.5, the chloride ions are chloride ions removed by the chloride removing system, the efficiency of removing the chloride ions by the system is 29.4%, and the rest 70.6% of chloride ions are still in the decomposing furnace.

In Table 1, the gas temperature in the high temperature cyclone in the cement kiln chlorine removal system of the application is 950-1000 ℃, the concentration of chloride ions in the filtered coarse particles is 3.0 after the high temperature cyclone is used for treatment, the coarse particles are sent back to the decomposing furnace, the concentration of chloride ions in the fine particles obtained by filtering through the bag type dust collector 4 is 11.5, the chloride ions are chloride ions removed by the chlorine removal system, the efficiency of removing the chloride ions by the cement kiln system of the application is 49.0%, and the rest 51.0% of the chloride ions are still in the decomposing furnace.

The cement kiln chlorine removal system has obviously better chlorine removal effect.

The preferred embodiments of the present application have been described in detail above with reference to the accompanying drawings, but the present application is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present application within the scope of the technical concept of the present application, and all the simple modifications belong to the protection scope of the present application.

In addition, the specific features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various possible combinations are not described further.

Moreover, any combination of the various embodiments of the application can be made without departing from the spirit of the application, which should also be considered as disclosed herein.

Claims (9)

1. A kiln tail waste gas dechlorination method for dechlorinating a cement kiln, which is characterized by comprising the following steps:

firstly, extracting waste gas of a kiln tail smoke chamber (10), and conveying the waste gas to a high-temperature cyclone (2) under the condition of sealing and heat preservation;

step two, after being treated by the high-temperature cyclone (2), coarse dust particles enter a decomposing furnace, and high-temperature gas is conveyed to a cold and hot air exchanger;

thirdly, cooling the high-temperature gas through the cold and hot air exchanger, and crystallizing the cooled chloride ions on the surface of the dust;

and fourthly, collecting dust with chloridion attached to the surface through a bag type dust collector (4), and enabling the filtered gas to enter an exhaust gas treatment system (6).

2. A kiln tail gas dechlorination method according to claim 1, characterised in that the temperature of the gas entering the high temperature cyclone (2) is not lower than 950 ℃.

3. The method for removing chlorine from kiln tail gas according to claim 1, wherein the temperature of the gas is not higher than 400 ℃ after the cooling by the cold-hot air exchanger.

4. The cement kiln chlorine removal system is characterized by comprising an air taking device, a high-temperature cyclone (2), a cold and hot air exchanger and a bag dust collector (4) which are sequentially connected, wherein an inlet of the air taking device is connected into a kiln tail smoke chamber (10) and exhaust gas is extracted from the kiln tail smoke chamber (10);

the cold and hot air exchanger comprises a cold air extraction device (31) and a cold and hot air interaction bin (32) connected with the cold air extraction device (31), an outlet of the high-temperature cyclone (2) is connected to the cold and hot air interaction bin (32), and high-temperature air and cold air extracted by the cold air extraction device (31) are subjected to heat exchange in the cold and hot air interaction bin (32);

and a heat insulation structure is arranged on a pipeline between the air taking device and the high-temperature cyclone cylinder (2).

5. The cement kiln chlorine removal system as defined in claim 4, wherein the inlet end of the air extraction device is provided with a duckbill air extraction opening (1), and the width of the opening of the duckbill air extraction opening (1) is gradually reduced from front to back.

6. The cement kiln chlorine removal system of claim 5, wherein the duckbill air extraction port (1) opening has a height H, H being no greater than 1.2m.

7. The chlorine removal system of a cement kiln according to claim 6, wherein the width of the widest part of the opening of the duckbill air taking opening (1) is L, and 4H is more than or equal to L and more than or equal to 3H.

8. The cement kiln chlorine removal system as defined in claim 7, wherein said air extraction means, said high temperature cyclone (2) and said insulating duct (12) are provided as an integral insulating structure.

9. The cement kiln chlorine removal system according to claim 8, wherein a connecting section (11) is further arranged between the duckbill air taking port (1) and the heat preservation air pipe (12), and the duckbill air taking port (1) is connected with the heat preservation air pipe (12) through the connecting section (11).