A dust cleaning system and method for a high-temperature baghouse

Abstract

The application discloses a dust cleaning method and system for a high-temperature bag-type dust collector. The dust cleaning system comprises a boiler, a dust collector, a dust cleaning device, a switching damper and a circulating cold air pipe. The boiler exhaust flue of the boiler is connected with the dust collector inlet flue, the dust collector inlet flue is connected with the air inlet of the dust collector, and the dust collector inlet flue is also connected with the circulating cold air pipe. The switching damper is arranged on the dust collector inlet flue, the outlet of the switching damper is communicated with the air inlet side of the dust collector, the two inlets of the switching damper are respectively communicated with the boiler exhaust flue side and the circulating cold air pipe side, and the circulating cold air pipe is used for being communicated with a cooling gas source. According to the application, the dust adhesion which is sensitive to temperature change in the flue gas is fully utilized, the cooling gas is mixed in the flue gas, the temperature of the flue gas is lowered, the dust adhesion on the surface of the filter bag is reduced, and the dust cleaning effect is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flue gas treatment, in particular to a dust cleaning method and system for a high-temperature bag-type dust collector. BACKGROUND

[0002] The high-temperature bag-type dust collector or high-temperature electric-bag composite dust collector uses special filter material resistant to high temperature, which is different from the conventional dust collector using chemical fiber filter material, and can be stably operated at a working condition with flue gas temperature greater than 250 DEG C for a long time, and the maximum temperature resistance can reach 800 DEG C. The high-temperature bag-type dust collector is often applied to the flue gas purification treatment scene with complex composition, high temperature, large variation of working conditions, and difficult to treat, such as non-ferrous (alumina, copper lead zinc, titanium dioxide), steel, cement, chemical industry, glass, biomass and other fields. The main dust cleaning methods of the high-temperature bag-type dust collector are gas cleaning and mechanical vibration cleaning, which cannot fully meet the actual dust cleaning effect under different industrial flue gas treatment working conditions. For example, the waste liquid incinerator of a chemical plant is affected by a large amount of sodium sulfate and other impurities in the flue gas, and serious hardening occurs on the surface of the filter bag, resulting in high filtration resistance; for example, a biomass combustion chain furnace has problems such as high sodium and potassium in the flue gas composition, incomplete combustion, and easy to cause the filter bag surface dust to be pasted, and the dust cleaning effect is not ideal. In practical application, the gas cleaning and mechanical vibration cleaning cannot meet the needs of dust cleaning and resistance reduction.

[0003] Therefore, it is urgent to propose a dust cleaning implementation scheme for the existing high-temperature bag-type dust collector to overcome the above-mentioned defects. SUMMARY

[0004] To solve the above technical problems, the present application provides a dust cleaning method and system for a high-temperature bag-type dust collector, which effectively improves the dust cleaning effect and provides a good technical guarantee for the reliability of system operation.

[0005] The present application provides a dust cleaning system for a high-temperature bag-type dust collector, comprising a boiler, a dust collector, a dust cleaning device, a switching damper and a circulating cold air pipe; the dust chamber of the dust collector is provided with a filter bag, and the bottom of the dust chamber is provided with a hopper, and the dust cleaning device is arranged on the upper part of the dust collector; wherein the boiler exhaust flue of the boiler is connected with the dust collector inlet flue, the dust collector inlet flue is connected with the air inlet of the dust collector, and the dust collector inlet flue is also connected with the circulating cold air pipe; the switching damper is arranged on the dust collector inlet flue, and the outlet of the switching damper is communicated with the air inlet side of the dust collector, the two inlets of the switching damper are respectively communicated with the side of the boiler exhaust flue and the side of the circulating cold air pipe, and the circulating cold air pipe is used for being communicated with a cooling gas source.

[0006] Optionally, the dust removal chamber of the dust remover is provided with a partition plate, and the dust removal chamber is divided into sub-dust removal chambers which are independent of each other, and each of the sub-dust removal chambers is correspondingly provided with one of the ash hoppers; and the dust remover inlet flue and the switching damper are correspondingly provided with one-to-one corresponding sub-dust removal chamber inlets.

[0007] Optionally, the temperature detection device is further provided for detecting the outlet flue gas temperature of the filter bag.

[0008] Optionally, the number of the temperature detection devices is at least the same as the number of the sub-dust removal chambers, and the temperature detection devices are used for detecting the outlet flue gas temperature of the filter bag in the corresponding sub-dust removal chamber.

[0009] Optionally, the clean gas chamber of the dust remover is connected with a heat recovery device through a dust remover outlet flue, the heat recovery device is connected with a chimney through a heat recovery device outlet flue, and the heat recovery device outlet flue is also connected with the circulating cold air pipe.

[0010] Optionally, the heat recovery device outlet flue is connected with the circulating cold air pipe through an induced draft flue, and the induced draft flue is provided with a circulating fan.

[0011] Optionally, the induced draft flue is provided with a first damper, and the induced draft flue between the first damper and the circulating fan is provided with an ambient air inlet, and the ambient air inlet is provided with a second damper.

[0012] Optionally, the ash removal device is a gas ash removal device or a mechanical vibration ash removal device.

[0013] Optionally, the filter bag is made of high-temperature-resistant alloy filter material.

[0014] The application further provides an ash removal method of the ash removal system based on the high-temperature bag-type dust remover, and the ash removal method comprises the following steps: opening the switching damper according to a preset first cooling ash removal condition; and starting the ash removal device according to a preset second cooling ash removal condition.

[0015] Optionally, the preset first cooling ash removal condition is that the operation time of the dust remover is greater than a preset operation time threshold value, or the pressure difference between the dust-impingement surface and the back-dust surface of the filter bag of the dust remover is greater than a preset pressure difference threshold value; and the preset second cooling ash removal condition is that the flue gas temperature at the outlet of the filter bag of the dust remover is lower than a preset temperature threshold value.

[0016] Compared with the prior art, the present application provides a dust cleaning solution for a high-temperature bag-type dust collector, and specifically, the dust cleaning system comprises a boiler, a dust collector, a dust cleaning device, a switching damper and a circulating cold air pipe; a filter bag is arranged in the dust removal chamber of the dust collector, and a dust hopper is arranged at the bottom of the dust removal chamber for collecting dust, and the dust cleaning device is arranged at the upper part of the dust collector; wherein the boiler exhaust flue of the boiler is connected with the inlet flue of the dust collector, the inlet flue of the dust collector is connected with the air inlet of the dust collector, and the inlet flue of the dust collector is also connected with the circulating cold air pipe; the switching damper is arranged on the inlet flue of the dust collector, and the outlet of the switching damper is in communication with the air inlet side of the dust collector, and the two inlets of the switching damper are in communication with the boiler exhaust flue side and the circulating cold air pipe side respectively, and the circulating cold air pipe is used for being in communication with a cooling gas source, so as to use low-temperature clean flue gas as cooling gas for dust cleaning treatment. In this way, the switching damper can be controlled according to actual treatment needs, the flow of high-temperature flue gas from the boiler exhaust flue and the flow of low-temperature cooling gas from the circulating cold air pipe can be adjusted; thus, the dust adhesion of the filter bag surface is reduced by taking advantage of the fact that the dust adhesion is sensitive to temperature change and by mixing cooling gas into the flue gas, so that the problem of dust adhesion of the high-temperature bag-type dust collector is effectively solved, and the reliable operation of the system is ensured.

[0017] In the preferred scheme of the present application, a partition is arranged in the dust removal chamber of the dust collector, and the dust removal chamber is divided into sub-dust removal chambers which are independent of each other, and correspondingly, the dust collector inlet flue and the switching damper are arranged in one-to-one correspondence with the air inlets of the sub-dust removal chambers. In this way, when the filter bag in a sub-dust removal chamber needs to be cleaned, the corresponding switching damper is controlled, so that the sub-dust removal chamber can be cooled and cleaned in a targeted manner, so that the normal passage of high-temperature flue gas generated by the boiler during dust cleaning of the dust collector is ensured, and the operation of the boiler and the dust collector is not greatly affected. Overall, the overall filtration air volume and air speed of the dust collector can be reasonably avoided from fluctuating greatly.

[0018] In another preferred scheme of the present application, the clean gas chamber of the dust collector is connected with a heat recovery device through a dust collector outlet flue, the heat recovery device is connected with a chimney through a heat recovery device outlet flue, and the heat recovery device outlet flue is also connected with the circulating cold air pipe. In this way, the low-temperature clean flue gas in the heat recovery device outlet flue is used as the cooling gas source, and the operation parameters of the main induced draft fan can be unchanged, and the influence on the flue gas system is small.

[0019] In still another preferred scheme of the present application, a first damper is arranged on the induced draft flue, and an ambient air inlet is arranged on the induced draft flue between the first damper and the circulating fan, and the ambient air inlet is provided with a second damper. In this way, the ambient air can be selected as the cooling gas source according to the system operation needs. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1An architecture principle diagram of a dust cleaning system of a high-temperature bag-type dust collector is provided for an embodiment of the present application.

[0021] Figure 2 A principle block diagram of a dust cleaning method of a high-temperature bag-type dust collector is provided for an embodiment of the present application.

[0022] In the figure:

[0023] Boiler 1, boiler exhaust flue 2, switching damper 3, air inlet 4, ash bucket 5, dust collector 6, filter bag 7, clean gas chamber 8, dust collector outlet flue 9, heat recovery device 10, heat recovery device outlet flue 11, induced draft fan 12, chimney 13, first damper 14, induced draft flue 15, circulating fan 16, circulating cold air pipe 17, dust cleaning device 18, temperature detection device 19, partition 20, dust collector inlet flue 21, sub dust removal chamber 22, second damper 23. DETAILED DESCRIPTION

[0024] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0025] In the prior art, based on good high-temperature resistance, high-temperature bag-type dust collectors are applied in different fields of flue gas treatment scenes. However, due to the influence of actual flue gas composition, dust hardening or bag sticking phenomenon occurs on the surface of the filter bag, which cannot be effectively treated by gas dust cleaning and mechanical vibration dust cleaning methods.

[0026] A related cloth bag dust collector flue gas conditioning device realizes conditioning treatment of flue gas by configuring a powder storage mechanism, a powder conveying mechanism and a powder recovery mechanism, and ensures stable operation of the cloth bag dust collector system. In specific implementation, the powder used for conditioning is a consumable raw material that needs to be replenished regularly, and a large number of equipment structures need to be configured, which is high in cost.

[0027] Another related glass kiln flue gas dust cleaning device performs dust cleaning in the mode of reverse blowing combined with acoustic dust removal, and makes the dust fall by "expansion" and "deflation" deformation of filter cloth and change of airflow direction, and simultaneously uses acoustic waves to clean the dust that cannot be cleaned by the main dust cleaning device. This scheme is more suitable for the working condition that the dust in the flue gas is not strong in adhesion, and when the dust is strong in adhesion and bag sticking occurs, the dust adhering to the surface of the filter bag cannot be effectively blown off, and it is difficult to achieve the effect of dust cleaning.

[0028] Still another related vibration dust cleaning device of a bag-type dust collector vibrates and cleans the filter bag through a mechanical structure cooperating with each other, and sprays air on the inner surface of the filter bag to clean the filter bag through the sprayed air. The device structure is relatively complex, and for the case of a large dust collector with several thousand or even tens of thousands of filter bags, it is difficult to ensure reliable operation of the device, and the economy is poor.

[0029] Based on this, the application provides a dust cleaning system of a high-temperature bag-type dust collector. By mixing cooling gas in the flue gas to be treated, the problem of dust sticking to the high-temperature bag-type dust collector is solved, and the technical effect of reliable operation of the system is achieved.

[0030] Please refer to Figure 1 , which is a principle architecture diagram of a dust cleaning system of a high-temperature bag-type dust collector provided by the application.

[0031] As shown in Figure 1 , the tail flue of the boiler 1 is connected to the dust collector inlet flue 21 through the boiler exhaust flue 2, the dust collector inlet flue 21 is connected to the air inlet 4 of the dust collector 6, and the flue gas generated by the operation in the boiler 1 enters the dust collector 6 through the air inlet 4. The dust collector 6 is a high-temperature bag-type dust collector, and a filter bag 7 is arranged inside the dust removal chamber of the dust collector 6. The bag body of the filter bag 7 can be made of high-temperature resistant alloy filter material, or other high-temperature resistant materials. The dust removal chamber is provided with a dust hopper 5 at the bottom for collecting dust, and a clean gas chamber 8 is arranged at the top of the dust removal chamber, and the clean flue gas can be discharged through the clean gas chamber 8. The clean gas chamber 8 is connected to the heat recovery device 10 through the dust collector outlet flue 9, and the high-temperature clean flue gas is recovered through the heat recovery device 10, and then the low-temperature clean flue gas enters the heat recovery device outlet flue 11, and can be discharged into the atmosphere through the chimney 13 under the action of the induced draft fan 12.

[0032] In this embodiment, the heat recovery device outlet flue 11 can also be connected to the dust collector inlet flue 21 through the circulating cold air pipe 17, so as to use the low-temperature clean flue gas as cooling gas for dust cleaning treatment. Specifically, the dust collector inlet flue 21 is provided with a switching damper 3, the outlet of the switching damper 3 is communicated with the air inlet 4, and the two inlets of the switching damper 3 are respectively communicated with the boiler exhaust flue 2 side and the circulating cold air pipe 17 side, so as to adjust the flow of high-temperature flue gas from the boiler exhaust flue 2 and the flow of low-temperature cooling gas from the circulating cold air pipe 17 according to the actual treatment needs.

[0033] In this way, the dust in the flue gas is sensitive to temperature changes (high-temperature viscosity is high, and low-temperature viscosity is low), and the flue gas is mixed with cooling gas, so that the temperature of the flue gas is reduced, thereby reducing the adhesion of the dust on the surface of the filter bag, and solving the problem of dust sticking to the high-temperature bag-type dust collector.

[0034] The flue gas purification process of the application will be described below Figure 1 .

[0035] Firstly, the high-temperature flue gas generated by the boiler 1 passes through the boiler exhaust flue 2, the dust collector inlet flue 21 and the air inlet 4 in sequence, enters the ash hopper 5 of the dust collector 6, and after being filtered by the filter bag 7 inside the dust collector 6, the clean flue gas enters the clean gas chamber 8 for collection, and then flows into the heat recovery device 10 for heat exchange and cooling. At this time, the low-temperature clean flue gas can flow through the heat recovery device outlet flue 11 and the induced draft fan 12 in sequence and then be discharged into the atmosphere through the chimney 13.

[0036] When the high-temperature dust collector needs to be cleaned, the switching damper 3 can be controlled to switch to the open inlet connected to the circulating cold air pipe 17. In this state, the low-temperature clean flue gas is led out of the heat recovery device outlet flue 11 and can be sent into the circulating cold air pipe 17 and then enter the dust collector 6 through the switching damper 3. The low-temperature clean flue gas can cool the dust on the surface of the filter bag 7 in the dust chamber. After the temperature drops, the dusting device 18 is opened to spray and clean the filter bag. Because the adhesion of the dust decreases after the temperature drops, the dusting effect is improved, and the influence of bag caking on the reliable operation of the system is effectively avoided.

[0037] In specific implementation, according to the application engineering experience of high-temperature bag-type dust collectors in various industries, for example, the dust of the high-temperature flue gas of the boiler in some industries has strong adhesion at high temperature and can adhere to the surface of the filter bag to cause bag caking. When the temperature drops to a certain value, the adhesion of the dust decreases, and the dusting device 18 arranged above the filter bag 7 can achieve good dusting effect. That is, the low-temperature clean flue gas after the heat recovery device 10 is extracted as a cooling gas source to cool the dust on the surface of the filter bag 7. After the temperature of the dust decreases, the dusting device 18 is opened to achieve dusting and avoid bag caking.

[0038] For example but not limited to, gas dusting and mechanical vibration dusting can be used. The gas dusting and mechanical vibration dusting can be realized by using the existing technology, so the details are not described herein.

[0039] In specific implementation, the switching damper 3 can be switched to the open inlet connected to the circulating cold air pipe 17 and the closed inlet connected to the boiler exhaust flue 2; that is, the gas flow entering the air inlet 4 is changed from high-temperature dust-containing flue gas to low-temperature clean flue gas to quickly perform temperature reduction before dusting. Of course, in specific implementation, the switching damper 3 can also be switched to the non-open inlet connected to the circulating cold air pipe 17 and the non-closed inlet connected to the boiler exhaust flue 2 to reasonably control the temperature drop speed, and the embodiments of the present application are not limited.

[0040] In order to reduce the fluctuation of the filter air volume and air speed of the dust collector, the dust collecting chamber in the dust collector 6 can be divided into a plurality of sub-dust collecting chambers 22. As shown in the figure, in the filter bag dust collecting chamber of the dust collector 6, the filter bag dust collecting chamber is divided into a plurality of sub-dust collecting chambers 22 by the partition 20, and each sub-dust collecting chamber 22 is independent of each other, and each sub-dust collecting chamber 22 is correspondingly provided with a dust hopper 5.

[0041] Correspondingly, the dust collector inlet flue 21 and the switching damper 3 are respectively arranged corresponding to each sub-dust collecting chamber 22, that is, the dust collector inlet flue 21 and the switching damper 3 are respectively arranged one by one corresponding to the air inlet of each sub-dust collecting chamber 22. According to the application, a plurality of relatively independent sub-dust collecting chambers 22, that is, filter bag partition, are arranged in the dust collector 6, each sub-dust collecting chamber 22 divides the filter bag dust collecting area into a plurality of independent areas, and the cooling gas entering one sub-dust collecting chamber 22 will not affect the filter bag in other areas. In this way, when the filter bag 7 in a certain sub-dust collecting chamber 22 needs to be cleaned, the corresponding switching damper 3 is controlled to be operated, so that the partition cooling and cleaning treatment can be carried out accordingly, so as to ensure that the high-temperature flue gas generated by the boiler can pass through the dust collector normally when the dust collector is cleaned, and the operation of the boiler 1 and the dust collector 6 will not be affected too much. Overall, the overall filter air volume and air speed of the dust collector can be reasonably avoided from fluctuating too much.

[0042] For the clean gas chamber 8, it can be processed in a partitioned manner, or it can not be processed in a partitioned manner as shown in the figure. The application embodiment is not limited.

[0043] In addition, the gas source used for cooling the dust attached to the filter bag 7 can be low-temperature clean flue gas at the rear stage of the boiler flue gas purification system, for example, but not limited to, flue gas after the waste heat boiler, flue gas after the heat recovery device such as the economizer or the air preheater, or ambient air.

[0044] Specifically, as shown in the figure, the induced draft flue 15 is communicated with the outlet flue 11 of the heat recovery device, and the circulating fan 16 is arranged between the induced draft flue 15 and the circulating cold air pipe 17, and the flow of the cooling gas can be controlled through the circulating fan 16. At the same time, the first damper 14 is arranged on the induced draft flue 15, and the ambient air inlet is arranged on the induced draft flue 15 between the first damper 14 and the circulating fan 16, and the ambient air inlet is provided with the second damper 23.

[0045] In practical applications, the cooling gas source can be selected by the first damper 14 and the second damper 23 as needed. For example, when the first damper 14 is opened and the second damper 23 is closed, the low-temperature clean flue gas backflow is used as the cooling gas source, and the operating parameters of the main induced draft fan 12 can not be changed, and the influence on the flue gas system is small. For another example, when the first damper 14 is closed and the second damper 23 is opened, the ambient air is used as the cooling gas source, and based on the changes of the ambient temperature and humidity and the changes of the mixed air volume, the air volume load borne by the main induced draft fan 12 during the dust removal process can fluctuate, and the original flue gas system is affected to a certain extent. The specific conditions can be determined according to the actual working conditions, and the embodiments of the present application are not limited.

[0046] In the present proposal, the cooling backflow air volume can be adjusted by frequency control of the circulating fan 16, the opening degree of the first damper 14 or the second damper 23, or by the circulating fan 16 and the corresponding damper. It can be understood that the backflow air volume should meet the needs of cooling the filter bag, and the specific conditions can be determined according to the cooling time and cooling temperature requirements. For example, the cooling temperature needs to be controlled above the acid dew point of the flue gas, so as to prevent the dust on the surface of the filter bag from being wetted and bonded due to flue gas condensation, and unnecessary acid corrosion is generated. In addition, a large air volume can quickly cool the filter bag, and a small air volume can slowly reduce the temperature of the filter bag, and reduce the influence of temperature mutation on various devices inside the dust collector.

[0047] In addition to the aforementioned dust removal system of the high-temperature bag-type dust collector, the embodiments of the present application also provide a dust removal method of a high-temperature bag-type dust collector. Please refer to Figure 2 , which is a principle block diagram of a dust removal method of a high-temperature bag-type dust collector provided by the embodiments of the present application. The dust removal method comprises the following steps:

[0048] S21, according to the preset first cooling and dust removal condition, open the switching damper 3, so that the cooling gas in the circulating cold air pipe 17 enters the dust collector 6 to cool the dust on the surface of the filter bag 7.

[0049] In specific implementation, the dust removal control can include two cases of "timed dust removal" and "constant pressure dust removal". For the timed dust removal, a fixed time interval can be used to open the cooling and dust removal according to the running experience value after the dust collector runs for a period of time; that is, the preset first cooling and dust removal condition can be that the running time of the dust collector is greater than the preset running time threshold. For the constant pressure dust removal, the filter resistance of the filter bag can be judged according to the pressure difference between the dust-approaching surface and the dust-backing surface of the filter bag, and the switching damper 3 is opened to start the cooling and dust removal when the filter resistance rises to a certain value. The pressure difference is judged by the differential pressure sensor (not shown in the figure) installed on the inside and outside of the filter bag, and the dust removal system can be automatically controlled to run through the program combined with the sensor signal for logical judgment. That is, the preset first cooling and dust removal condition can be that the pressure difference between the dust-approaching surface and the dust-backing surface of the filter bag is greater than the preset pressure difference threshold.

[0050] In other possible implementation schemes, the pressure difference of the inlet and outlet of each sub-zone can also be used to determine the dusting.

[0051] S22, according to the preset second cooling and dusting condition, the dusting device 18 is started to perform dusting treatment on the filter bag.

[0052] In a specific implementation, the low-temperature flue gas can cool the dust on the surface of the filter bag 7 in the dust removal sub-zone, and when the temperature detection device 19 detects that the flue gas at the outlet of the filter bag 7 is cooled to a certain temperature, that is, the function of reducing viscosity is needed, the dusting device 18 is opened to perform dusting treatment on the filter bag. That is, the preset second cooling and dusting condition can be that the temperature of the flue gas at the outlet of the filter bag 7 is lower than a preset temperature threshold.

[0053] In a specific implementation, the number of temperature detection devices 19 is at least the same as the number of sub-dust removal chambers 22, and in combination with Figure 1 As shown in the figure, the temperature detection device 19 is used to detect the temperature of the flue gas at the outlet of the filter bag 7 in the corresponding sub-dust removal chamber 22.

[0054] In other possible implementation schemes, according to the running experience value of the cooling time length, when the dust layer is cooled and the viscosity is reduced after reaching the preset time length of cooling, the dusting device 18 is opened to perform dusting treatment.

[0055] In the actual trial application of a certain chemical plant, the specific data are described as follows. The chemical plant has two waste liquid incinerators. The boiler mainly incinerates organic waste liquid (saponification liquid, papermaking black liquor, etc.), waste oil, waste gas, etc. In this scene, the flue gas dust concentration is about 5-10 g / Nm³, and the main component of the flue gas fly ash is sodium carbonate, with a content of about 90%, which belongs to high-sodium dust with strong viscosity.

[0056] One of the incinerators is equipped with a conventional electric bag dust collector A, and the running flue gas temperature is about 180°C. The dust collector A runs stably, the normal running resistance is maintained at 300-600 Pa, the filter bag dusting system works normally, and there is no case of bag clogging.

[0057] The other incinerator is equipped with a high-temperature electric bag dust collector B, and the running flue gas temperature is about 350°C. The running resistance of the dust collector B will continuously increase with the running time. After about 3-4 days of normal operation, the resistance of the dust collector B will increase to about 4500 Pa, and the highest will reach 5700 Pa. Under the condition that the dust collector structure and the flue gas dust composition are similar, the dust collector temperature has a great influence on the work of the dusting system.

[0058] Dust collector B is a high-temperature dust collector, and the dust cleaning system has an unsatisfactory dust cleaning effect, and the filter bag is subject to dust accumulation and bag clogging. To cope with the high resistance operation of dust collector B, the dust cleaning system of the high-temperature bag-type dust collector described in the foregoing embodiments is reformed, and when the resistance of the dust collector exceeds about 5000 Pa, the dust collector B is cleaned after the temperature of the flue gas is reduced. The actual temperature reduction and dust cleaning effect is shown in the following table:

[0059]

[0060] From the data in the above table, it can be seen that the effect of dust collector B using temperature reduction and dust cleaning is remarkable. Before temperature reduction and dust cleaning, the resistance is greater than 4500 Pa, and the operating temperature is greater than 370℃, indicating that the gas permeability of the filter bag is severely reduced before dust cleaning, and bag clogging occurs. After temperature reduction and dust cleaning, the resistance is obviously reduced to within 200 Pa, indicating that the surface dust of the filter bag is well removed, and the gas permeability of the filter bag is restored. After dust cleaning, the operating temperature of dust collector B returns to the high-temperature condition, and the resistance of the filter bag slowly increases within the next 24 hours. During the system operation, the cooling and dust cleaning can be controlled to start, so as to meet the requirements of reliable operation of the system.

[0061] Compared with the existing conventional dust cleaning process, the dust cleaning method claimed in the present application includes the following main differences:

[0062] 1. Principle difference: The existing dust cleaning method for coping with bag clogging mainly enhances the deformation amount and increases the deformation acceleration value of the filter bag, and adjusts the flue gas. The present scheme utilizes the influence of temperature change on the adhesion of dust (high-temperature dust has high adhesion, and low-temperature dust has low adhesion), changes the temperature of the dust layer on the surface of the filter bag 7, and reduces the adhesion of the dust layer after temperature reduction, that is, the physical property change of the ash content is realized without changing the composition of the flue gas, and then the dust is cleaned to achieve a better dust cleaning effect, high reliability, and reasonable control of operation cost and equipment configuration cost. In addition, there is no addition of additives, and the purity of the ash content is higher, and the utilization value is higher.

[0063] 2. Structural difference: The present scheme does not change the original conventional dust cleaning device and dust cleaning structure, and adds a circulating cooling air system, such as an air duct, a fan, a valve, and a detection and control system, to achieve the above-mentioned cooling and dust cleaning effect. Compared with the prior art, the present scheme has fewer devices and a simpler structure, high reliability, no need for consumable materials for conditioning, and is suitable for modification of existing systems.

[0064] It should be understood that other functional configurations of the dust cleaning system of the high-temperature bag-type dust collector can be realized by using the existing technology, and therefore will not be described again.

[0065] In addition, the ordinal numbers "first" and "second" and the like used herein are only used to describe the same function of the components or structures in the technical solutions. It can be understood that the use of the ordinal numbers does not constitute a limitation on the understanding of the technical solutions claimed by the present application.

[0066] The above is only the preferred embodiment of the present application, and it should be pointed out that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application.

Claims

1. A soot cleaning system for a high temperature baghouse, characterized by, The boiler, the dust collector, the ash cleaning device, the switching damper and the circulating cold air pipe are included; the dust collecting chamber of the dust collector is internally provided with filter bags, and the bottom of the dust collecting chamber is provided with an ash hopper, and the ash cleaning device is arranged at the upper portion of the dust collector; The boiler exhaust flue of the boiler is connected with the dust collector inlet flue, the dust collector inlet flue is connected with the air inlet of the dust collector, and the dust collector inlet flue is also connected with the circulating cold air pipe; The switching damper is arranged on the dust collector inlet flue, and the outlet of the switching damper is in communication with the air inlet side of the dust collector, the two inlets of the switching damper are respectively in communication with the boiler exhaust flue side and the circulating cold air pipe side, and the circulating cold air pipe is used for being in communication with a cooling gas source; The clean gas chamber of the dust collector is connected with the heat recovery device through the dust collector outlet flue, the heat recovery device is connected with the chimney through the heat recovery device outlet flue, the heat recovery device outlet flue is also connected with the circulating cold air pipe, the heat recovery device outlet flue is connected with the circulating cold air pipe through the induced draft flue, and the induced draft flue is provided with a circulating fan; A first damper is arranged on the induced draft flue, and an ambient air inlet is arranged on the induced draft flue between the first damper and the circulating fan, and the ambient air inlet is provided with a second damper.

2. The soot cleaning system of a high temperature baghouse according to claim 1, wherein The dust collecting chamber of the dust collector is provided with a partition plate, and the dust collecting chamber is divided into sub-dust collecting chambers which are independent of each other, and each of the sub-dust collecting chambers is correspondingly provided with one ash hopper; correspondingly, the dust collector inlet flue and the switching damper are respectively arranged one by one in correspondence with the air inlets of the sub-dust collecting chambers.

3. The soot cleaning system of a high temperature baghouse according to claim 2, wherein A temperature detection device is further included for detecting the outlet flue gas temperature of the filter bags.

4. The soot cleaning system of a high temperature baghouse according to claim 3, wherein The number of the temperature detection devices is at least the same as the number of the sub-dust collecting chambers, and the temperature detection devices are used for detecting the outlet flue gas temperature of the filter bags in the corresponding sub-dust collecting chambers.

5. The soot cleaning system of a high temperature baghouse according to claim 1, wherein The ash cleaning device is a gas ash cleaning device or a mechanical vibration ash cleaning device.

6. The soot cleaning system of a high temperature baghouse according to any one of claims 1 to 4, wherein The filter bags are made of high-temperature-resistant alloy filter material.

7. A method of cleaning the ash system of a high temperature baghouse according to any one of claims 1 to 6, characterized in that, The ash cleaning method includes the following steps: According to the preset first cooling ash cleaning condition, the switching damper is opened; According to the preset second cooling ash cleaning condition, the ash cleaning device is started.

8. The method of claim 7, wherein, The preset first cooling ash cleaning condition is that the running time of the dust collector is greater than a preset running time threshold value, or the pressure difference between the dust-impinging surface and the back-dust surface of the filter bags of the dust collector is greater than a preset pressure difference threshold value; The preset second cooling ash cleaning condition is that the flue gas temperature at the outlet of the filter bags of the dust collector is lower than a preset temperature threshold value.

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