Municipal sludge incineration flue gas purification system

Abstract

The invention discloses a municipal sludge incineration flue gas purification system which comprises a flue gas inlet pipe, an air preheater, a waste heat boiler, an electrostatic dust collector and a high-voltage pulse discharge purification device. The air preheater is provided with a preheating flue capable of exchanging heat and an air channel; the waste heat boiler is provided with a boiler flue capable of exchanging heat and a heating containing cavity, and the inlet end of the boiler flue communicates with the outlet end of the preheating flue. The electrostatic dust collector is provided with an electrostatic dust collection channel capable of exchanging heat and a heating flue, the inlet end of the electrostatic dust collection channel communicates with the outlet end of the boiler flue, the inlet end of the heating flue communicates with the smoke inlet pipe, and the outlet end of the heating flue communicates with the inlet end of the preheating flue. According to the scheme, the problem that tar in sludge incineration flue gas blocks the electrostatic dust collector can be solved, the flue gas waste heat recovery rate is increased, waste water is not generated, chemicals and catalysts are not consumed, and the cost is low. In addition, the flue gas purification method is short in process and small in occupied area, and the occupied area is saved by 40% or above compared with a traditional flue gas purification method.

Description

Technical Field

[0001] The invention relates to the technical field of municipal sludge incineration treatment, and in particular to a municipal sludge incineration flue gas purification system. Background Art

[0002] Municipal sludge, as a typical urban solid waste, has huge output and high harmfulness, and needs to be treated harmlessly in a timely manner.

[0003] For example, patent CN219272640U discloses an ultra-low emission system for high-sulfur sludge incineration flue gas, which includes a circulating semi-dry desulfurization system, a bag dust removal system and a wet scrubbing system arranged in sequence along the flue gas treatment direction. The ash discharge outlet of the dust collector is connected to the desulfurizer mixing and injection device, and the outlets of the desulfurizer mixing and injection device and the activated carbon injection device are respectively connected to the mixing flue through the injection port. Under the premise of ensuring the emission indicators, the material consumption and operating costs are effectively reduced, and the feasibility of comprehensively promoting the concept of ultra-low emission of industrial waste gas in the solid waste field is improved.

[0004] However, the traditional sludge incineration flue gas process uses cyclone dust collectors, bag dust collectors and spraying methods, which have long processes, many equipment, and cannot recover the flue gas waste heat well. In addition, the traditional desulfurization and denitrification uses dry, semi-dry desulfurization and CR denitrification (selective catalytic reduction denitrification), which consumes a lot of industrial water and desulfurizers, and the desulfurization wastewater needs to be treated separately. CR denitrification requires the flue gas temperature to be no less than 300℃, which limits the front-end flue gas waste heat recovery rate, and the catalyst purchase cost is expensive. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and propose a municipal sludge incineration flue gas purification system to solve the technical problems that the sludge incineration flue gas process in the prior art adopts cyclone dust collector, bag dust collector and spraying, the process is long, the equipment is many, and the flue gas waste heat cannot be recovered well, and a large amount of industrial water and desulfurizer are consumed, and the desulfurization wastewater also needs to be treated separately.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: The present invention provides a municipal sludge incineration flue gas purification system, comprising: A smoke inlet pipe, used for introducing smoke; An air preheater, comprising a preheating flue and an air passage capable of exchanging heat, wherein the inlet end of the preheating flue is connected to the smoke inlet pipe; A waste heat boiler having a boiler flue and a heating chamber capable of exchanging heat, wherein the inlet end of the boiler flue is connected to the outlet end of the preheating flue; An electrostatic precipitator having an electrostatic precipitator channel and a heating flue capable of exchanging heat, wherein the inlet end of the electrostatic precipitator channel is connected to the outlet end of the boiler flue, the inlet end of the heating flue is connected to the smoke inlet pipe, and the outlet end thereof is connected to the inlet end of the preheating flue; and A high-voltage pulse discharge purification device is provided with a purification channel, wherein the inlet end of the purification channel is connected to the outlet end of the electrostatic dust removal channel.

[0007] In some embodiments, the high-voltage pulse discharge purification device includes a primary high-voltage pulse discharge purification device and a secondary high-voltage pulse discharge purification device, the purification channel includes a primary channel located in the primary high-voltage pulse discharge purification device and a secondary channel located in the secondary high-voltage pulse discharge purification device, and the outlet end of the heating flue, the primary channel and the secondary channel are connected in sequence; The residence time of the flue gas in the primary channel is t1, and the residence time in the secondary channel is t2, satisfying t1≥t2.

[0008] In some embodiments, the municipal sludge incineration flue gas purification system also includes an activated carbon box, a smoke exhaust pipe and a smoke exhaust valve. The activated carbon box and the smoke exhaust pipe are respectively connected to the outlet of the secondary channel, and the smoke exhaust valve is arranged on the smoke exhaust pipe.

[0009] In some embodiments, two opposite side walls of the heating flue are respectively provided with a plurality of guide plates, and the plurality of guide plates on both sides are arranged alternately in sequence along the flue gas flow direction; Among them, the inlet end and the outlet end of the heating flue are respectively arranged on both sides of the arrangement direction of the plurality of guide plates.

[0010] In some embodiments, the heating flue is located at the tar storage position of the electrostatic precipitator channel and is connected to two flushing pipes. The two flushing pipes are respectively arranged on both sides of the layout direction of the multiple guide plates, and each flushing pipe is provided with a valve, one of the flushing pipes is used to introduce a flushing solution.

[0011] In some embodiments, one of the two flushing tubes is connected to the heating chamber.

[0012] In some embodiments, the inner wall material of the heating flue is duplex stainless steel.

[0013] In some embodiments, the outlet end of the air passage is used to communicate with the combustion chamber of the incinerator.

[0014] In some embodiments, the smoke inlet pipe includes a main smoke inlet pipe, two smoke inlet branches and two regulating valves. The main smoke inlet pipe is respectively connected to the two smoke inlet branches. One of the two smoke inlet branches is connected to the entrance of the preheating flue, and the other is connected to the entrance of the electrostatic dust removal channel. The two regulating valves are respectively arranged on the two smoke inlet branches.

[0015] In some embodiments, the flue gas flow rate input into the electrostatic precipitator channel is q1, and the flue gas flow rate input into the preheating flue is q2, satisfying 0.15≤q1 / q2≤0.18.

[0016] Compared with the prior art, in the municipal sludge incineration flue gas purification system provided by the present invention, the municipal sludge incineration high-temperature flue gas is divided into two parts, one part is used for waste heat through the air preheater and the waste heat boiler; the other part is first introduced into the heating flue of the electrostatic precipitator to exchange heat with the tar in the electrostatic precipitator channel, heat the tar removed in the electrostatic precipitator channel, ensure the fluidity of the tar, so as to facilitate collection, and overcome the problem of tar solidification and adhesion causing the electrostatic precipitator to be blocked, and this part of the flue gas is combined with the previous part of the high-temperature flue gas after heat exchange with the tar in the electrostatic precipitator channel in the heating flue, and enters the air preheater for waste heat utilization. The low-temperature flue gas after the waste heat utilization of the air preheater and the waste heat boiler enters the electrostatic precipitator channel for dust removal and oil removal; the low-temperature flue gas after dust removal and oil removal is then introduced into the high-voltage pulse discharge purification device, so that the nitrogen oxides, sulfur dioxide and dioxins in the flue gas are removed, and after the flue gas purification is completed, it is discharged through the chimney to meet the standards.

[0017] In this way, this scheme realizes primary waste heat recovery through air preheater and waste heat boiler, and uses electrostatic precipitator to remove dust and tar by coupling, and can use waste heat of incineration flue gas to heat the removed tar, ensure tar fluidity and collection, overcome the problem of tar in sludge incineration flue gas blocking electrostatic precipitator, and improve flue gas waste heat recovery rate. The present invention can also use high-voltage nanosecond pulse discharge, with the highest discharge voltage reaching 30kV, discharge power 20~100kW, and voltage frequency 60kHz, so it can generate a large number of active oxidizing groups in a very short time. In addition to realizing the function of removing dust and sulfur dioxide (need to add desulfurizer) of traditional DC pulse discharge device, it can also remove odor, nitrogen oxides, and dioxins at the same time, without generating wastewater, consuming agents and catalysts, and low cost. In addition, the flue gas purification method has a short process and a small footprint, which saves more than 40% of the area compared with the traditional flue gas purification method. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of a municipal sludge incineration flue gas purification system provided by an embodiment of the present invention; Figure 2 yes Figure 1Schematic diagram of the heating flue of the electrostatic precipitator.

[0019] Description of reference numerals: 1. Smoke inlet pipe; 11. Air inlet main pipe; 12. Air inlet branch pipe; 13. Regulating valve; 2. Air preheater; 3. Waste heat boiler; 4. Electrostatic precipitator; 4a. Heating flue; 4a1. Inlet end of heating flue; 4a2. Outlet end of heating flue; 41. Guide plate; 42. Flushing pipe; 5. High-voltage pulse discharge purification device; 51. First-level high-voltage pulse discharge purification device; 52. Second-level high-voltage pulse discharge purification device; 6. Activated carbon box; 7. Smoke exhaust pipe; 71. Smoke exhaust valve; 8. Incinerator; 9. Sludge drying equipment. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] In order to solve the technical problems that the sludge incineration flue gas process in the prior art adopts cyclone dust collector, bag dust collector and spraying, the process is long, the equipment is many, the flue gas waste heat cannot be recovered well, a large amount of industrial water and desulfurizer are consumed, and the desulfurization waste water needs to be treated separately, the present invention provides a municipal sludge incineration flue gas purification system, which can overcome the problem of electrostatic precipitator blocking due to solidification and adhesion of tar in the sludge incineration flue gas, and improve the flue gas waste heat recovery rate, and does not generate wastewater, consume agents and catalysts, and has low cost. The flue gas purification method has a short process and small footprint, which saves more than 40% of land compared with traditional flue gas purification methods.

[0022] See also Figure 1 , Figure 1 It is a structural schematic diagram of a municipal sludge incineration flue gas purification system in one embodiment of the present invention, which comprises a smoke inlet pipe 1, an air preheater 2, a waste heat boiler 3, an electrostatic precipitator 4 and a high-voltage pulse discharge purification device 5; the smoke inlet pipe 1 is used to introduce smoke; the air preheater 2 has a preheating flue and an air channel capable of heat exchange, and the inlet end of the preheating flue is connected to the smoke inlet pipe 1; the waste heat boiler 3 has a boiler flue and a heating cavity capable of heat exchange, and the inlet end of the boiler flue is connected to the outlet end of the preheating flue; the electrostatic precipitator 4 has an electrostatic precipitator channel and a heating flue 4a capable of heat exchange, the inlet end of the electrostatic precipitator channel is connected to the outlet end of the boiler flue, the inlet end 4a1 of the heating flue is connected to the smoke inlet pipe 1, and its outlet end is connected to the inlet end of the preheating flue; the inlet end of the purification channel of the high-voltage pulse discharge purification device 5 is connected to the outlet end of the electrostatic precipitator channel.

[0023] In the municipal sludge incineration flue gas purification system provided by the present invention, the municipal sludge incineration high-temperature flue gas is divided into two parts, one part is used for waste heat through the air preheater 2 and the waste heat boiler 3; the other part is first introduced into the heating flue 4a of the electrostatic precipitator 4 to exchange heat with the tar in the electrostatic precipitator channel, heat the tar removed in the electrostatic precipitator channel, ensure the fluidity of the tar, so as to facilitate collection, and overcome the problem of tar blocking the electrostatic precipitator 4, and this part of the flue gas is combined with the previous part of the high-temperature flue gas after heat exchange with the tar in the electrostatic precipitator channel in the heating flue 4a, and enters the air preheater 2 for waste heat utilization. The low-temperature flue gas after the waste heat utilization of the air preheater 2 and the waste heat boiler 3 enters the electrostatic precipitator channel for dust removal and oil removal; the low-temperature flue gas after dust removal and oil removal is then introduced into the high-voltage pulse discharge purification device 5, so that the nitrogen oxides, sulfur dioxide, and dioxins in the flue gas are removed. After the flue gas purification is completed, it is discharged through the chimney to meet the standards.

[0024] In this way, this scheme realizes primary waste heat recovery through air preheater 2 and waste heat boiler 3, and uses electrostatic precipitator 4 to remove dust and tar by coupling, and can use the waste heat of incineration flue gas to heat the removed tar, ensure the fluidity and collection of tar, overcome the problem of tar in sludge incineration flue gas blocking electrostatic precipitator 4, and improve the waste heat recovery rate of flue gas. The present invention can also use high-voltage nanosecond pulse discharge, with a maximum discharge voltage of 30kV, a discharge power of 20-100kW, and a voltage frequency of 60kHz, so that a large number of active oxidizing groups can be generated in a very short time. In addition to realizing the function of removing dust and sulfur dioxide (need to add desulfurizer) of traditional DC pulse discharge device, it can also remove odor, nitrogen oxides, and dioxins at the same time, without generating wastewater, consuming agents and catalysts, and low cost. In addition, the flue gas purification method has a short process and a small footprint, which saves more than 40% of the area compared with the traditional flue gas purification method.

[0025] It should be noted that after a part of the high-temperature flue gas passes through the air preheater 2 and the waste heat boiler 3 for waste heat utilization, the temperature drops from 850-900°C to 200-250°C, forming low-temperature flue gas; the outlet end of the air channel is used to connect to the combustion chamber of the incinerator 8, so that the ambient air after heat exchange in the air preheater 2 enters the incinerator 8 as primary air supply, and the saturated steam after heat exchange in the waste heat boiler 3 can enter the municipal sludge drying equipment 9; the other part of the high-temperature flue gas first enters the electrostatic precipitator 4 for heat exchange, and then enters the air preheater 2.

[0026] After the low-temperature flue gas enters the electrostatic precipitator 4, the dust content is 22000~25000mg / Nm 3 Reduced to 1100~1250mg / Nm 3 , tar content from 50 to 150 mg / Nm 3 Reduced to 5-15 mg / Nm 3At the same time, part of the high-temperature flue gas enters the heating flue 4a of the electrostatic precipitator 4 to heat the tar in the electrostatic precipitator channel. After the tar is heated, the temperature is 300-350°C to ensure the fluidity of the tar.

[0027] In addition, it should be understood that the preheating flue and the air channel of the air preheater 2 are isolated from each other and are not connected. The boiler flue and the heating chamber of the waste heat boiler 3 are also isolated from each other and are not connected. Similarly, the electrostatic precipitator channel of the electrostatic precipitator 4 is isolated from the heating flue 4a and is not connected; specifically, the heating flue 4a is formed by an oil receiving plate sandwich, which is a hollow duplex stainless steel cavity, with tar on the outside of the cavity and high-temperature flue gas inside the cavity.

[0028] In one embodiment, the high-voltage pulse discharge purification device 5 includes a first-level high-voltage pulse discharge purification device 51 and a second-level high-voltage pulse discharge purification device 52, the purification channel includes a first-level channel located in the first-level high-voltage pulse discharge purification device 51 and a second-level channel located in the second-level high-voltage pulse discharge purification device 52, and the outlet end 4a2 of the heating flue, the first-level channel and the second-level channel are connected in sequence; wherein, the residence time of the flue gas in the first-level channel is t1, and the residence time in the second-level channel is t2, satisfying that t1≥t2.

[0029] In this embodiment, a two-stage high-voltage pulse discharge purification device 5 is provided. Specifically, after the flue gas after de-oiling and dust removal enters the first-stage high-voltage pulse discharge purification device 51, hydrogen sulfide and water in the flue gas are removed, and the removal rates are 95% and 99% respectively; the dust in the flue gas is also further removed, and the dust content is from 1100 to 1250 mg / Nm 3 Reduced to 22-25 mg / Nm 3 The high-voltage pulse discharge purification device 5 uses alternating current as power source. Through nanosecond pulse discharge, it can reach a discharge voltage of 30kV, a discharge power of 20-100kW, and a discharge frequency of 60kHz, generating a large number of oxygen free radicals, hydroxyl free radicals and other free radicals with strong oxidizing properties and chemical reaction activity. The pollutant molecules are oxidized into carbon dioxide and water molecules, as well as other simple and stable oxides or single substances. The residence time of the flue gas in the first-level high-voltage pulse discharge purification device 51 is controlled to be 15-20 seconds.

[0030] The flue gas after primary purification is passed into the secondary high-voltage pulse discharge purification device 52, and the nitrogen oxides, sulfur dioxide and dioxins in the flue gas are removed, with removal rates of 60%, 90% and 99% respectively. The residence time of the flue gas in the secondary high-voltage pulse discharge purification device 52 is controlled at 10 to 15 seconds.

[0031] In one embodiment, the municipal sludge incineration flue gas purification system also includes an activated carbon box 6, a smoke exhaust pipe 7 and a smoke exhaust valve 71. The activated carbon box 6 and the smoke exhaust pipe 7 are respectively connected to the outlet of the secondary channel, and the smoke exhaust valve 71 is arranged on the smoke exhaust pipe 7.

[0032] In this embodiment, the activated carbon box 6 can be selected for connection according to actual conditions, so that the flue gas passing through the two-stage high-voltage pulse discharge purification device 5 can be discharged directly to meet the standards, or it can enter the activated carbon box 6 for emergency treatment and then meet the standards for discharge.

[0033] In one embodiment, see Figure 2 The opposite side walls of the heating flue 4a are respectively provided with a plurality of guide plates 41, and the plurality of guide plates 41 on both sides are arranged alternately in sequence along the flue gas flow direction; wherein the inlet end 4a1 and the outlet end of the heating flue are respectively arranged on both sides of the arrangement direction of the plurality of guide plates 41.

[0034] In this embodiment, a plurality of guide plates 41 are arranged in the heating flue 4a as described above to extend the flow path of the flue gas, thereby improving the heat exchange rate between the flue gas in the heating flue 4a and the tar in the electrostatic precipitator channel, and ensuring the fluidity of the tar for easy collection.

[0035] In one embodiment, the heating flue 4a is located at the tar storage position of the electrostatic precipitator channel and is connected to two flushing pipes 42. The two flushing pipes 42 are respectively arranged on both sides of the arrangement direction of the multiple guide plates 41, and each flushing pipe 42 is provided with a valve, and one of the flushing pipes 42 is used to introduce a flushing solution.

[0036] In this embodiment, two flushing pipes 42 are also connected to the heating flue 4a, so that when the system is shut down, high-pressure hot water can be pumped into the heating flue 4a through one flushing pipe 42 for flushing, and discharged from the other flushing pipe 42, to ensure that the flow channel in the heating flue 4a is unobstructed. It should be noted that in the example of the attached figure, the inlet end 4a1 of the heating flue and the flushing pipe 42 for flushing liquid are located on the same side (left side) of the guide plate 41, and the outlet end 4a2 of the heating flue and the flushing pipe 42 for flushing liquid are located on the same side (right side) of the guide plate 41.

[0037] In one embodiment, one of the two flushing pipes 42 is connected to the heating chamber. In addition, the inner wall of the heating flue 4a is made of duplex stainless steel.

[0038] In this embodiment, the flushing pipe 42 is connected to the heating chamber of the waste heat boiler 3 so that the steam in the waste heat boiler 3 can be introduced into the heating flue 4a for flushing. At the same time, the inner wall material of the heating flue 4a is bidirectional stainless steel to extend the service life of the oil receiving plate interlayer corresponding to the heating flue 4a.

[0039] In one embodiment, the smoke inlet pipe 1 includes a smoke inlet main pipe, two smoke inlet branch pipes and two regulating valves 13. The smoke inlet main pipe is connected to the two smoke inlet branch pipes respectively. One of the two smoke inlet branch pipes is connected to the entrance of the preheating flue, and the other is connected to the entrance of the electrostatic dust removal channel. The two regulating valves 13 are respectively arranged on the two smoke inlet branch pipes.

[0040] In this embodiment, the two smoke inlet branches are respectively connected to the air preheater 2 and the electrostatic precipitator 4, and the smoke flow rates of the two branches are flexibly adjusted through the regulating valve 13 to improve flexibility.

[0041] In one of the embodiments, the flue gas flow rate input into the electrostatic precipitator channel is q1, and the flue gas flow rate input into the preheating flue is q2, satisfying 0.15≤q1 / q2≤0.18.

[0042] In this embodiment, the flue gas flow rate entering the air preheater 2 is greater than the flue gas flow rate directly entering the electrostatic precipitator 4, and the flue gas direction is reasonably distributed to ensure that the heat recovery rate is improved while overcoming the tar pollution blocking the electrostatic precipitator 4. Specifically, in one embodiment, the incineration flue gas volume is 10000Nm 3 / h, temperature 850℃, dust content 13000mg / Nm 3 、Nitrogen oxide content 250mg / Nm 3 、Hydrogen sulfide content 120mg / Nm 3 、Sulfur dioxide 800mg / Nm 3 , tar content 80 mg / Nm 3 ; 1500Nm 3 / h The incineration flue gas is passed into the electrostatic precipitator 4 for heat exchange, and the remaining 8500Nm 3 / h is sequentially passed into the air preheater 2 and the waste heat boiler 3. That is, in this embodiment, q1 is 1500Nm 3 / h, q2 is 8500Nm 3 / h.

[0043] In order to better understand the present invention, the following Figure 1 and Figure 2 The technical solution of the present invention is described in detail: 1) Incineration flue gas volume 10000Nm 3 / h, temperature 850℃, dust content 13000mg / Nm 3 、Nitrogen oxide content 250mg / Nm 3 、Hydrogen sulfide content 120mg / Nm 3 、Sulfur dioxide 800mg / Nm 3 , tar content 80mg / Nm 3 ; 1500Nm 3 / h The incineration flue gas is passed into the electrostatic precipitator 4 for heat exchange, and the remaining 8500Nm 3 / h is sequentially introduced into the air preheater 2 and the waste heat boiler 3 as an example, the incineration flue gas directly entering the air preheater 2 and the waste heat boiler 3 after waste heat utilization has its temperature reduced from 850°C to 250°C; 2) The low-temperature flue gas from the waste heat boiler 3 enters the electrostatic precipitator 4 to simultaneously complete de-oiling and dust removal, and the dust content is reduced to 650 mg / Nm 3 , tar content reduced to 8 mg / Nm 3 , 1500Nm in step (1) 3 / h The incineration flue gas is passed into the oil receiving plate interlayer of the electrostatic precipitator 4 to indirectly heat the tar. The tar temperature is heated to 350°C and flows to the tar collection box with good fluidity; 1500Nm 3 / h of incineration flue gas is cooled to 550℃ after heat exchange and then enters air preheater 2; 3) The flue gas purified by the electrostatic precipitator 4 enters the first-level high-voltage pulse discharge purification device 51. After high-voltage, nanosecond pulse discharge oxidation, the hydrogen sulfide content in the flue gas is reduced to 10 mg / Nm 3 Below, the dust content is further reduced to 15mg / Nm 3 Below, sulfur dioxide concentration is reduced to 240mg / Nm 3 ; 4) After being purified by the first-level high-voltage pulse discharge purification device 51, the flue gas enters the second-level high-voltage pulse discharge purification device 52, and the nitrogen oxide content in the flue gas is reduced to 100mg / Nm 3 , sulfur dioxide concentration reduced to 24mg / Nm 3 ; 5) The flue gas composition after passing through the secondary high-voltage pulse discharge purification device 52 meets the "Emission Standards for Air Pollutants from Incineration of Domestic Waste" and does not need to enter the activated carbon box 6, and can meet the emission standards; it can also enter the activated carbon box 6 for emergency treatment under special circumstances and meet the emission standards.

[0044] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A municipal sludge incineration flue gas purification system, characterized in that: include: Smoke inlet pipe; An air preheater, comprising a preheating flue and an air passage capable of exchanging heat, wherein the inlet end of the preheating flue is connected to the smoke inlet pipe; A waste heat boiler having a boiler flue and a heating chamber capable of exchanging heat, wherein the inlet end of the boiler flue is connected to the outlet end of the preheating flue; An electrostatic precipitator having an electrostatic precipitator channel and a heating flue capable of heat exchange, wherein the inlet end of the electrostatic precipitator channel is connected to the outlet end of the boiler flue, the inlet end of the heating flue is connected to the smoke inlet pipe, and the outlet end thereof is connected to the inlet end of the preheating flue; and A high-voltage pulse discharge purification device is provided with a purification channel, wherein the inlet end of the purification channel is connected to the outlet end of the electrostatic dust removal channel.

2. The municipal sludge incineration flue gas purification system according to claim 1, characterized in that: The high-voltage pulse discharge purification device includes a primary high-voltage pulse discharge purification device and a secondary high-voltage pulse discharge purification device, the purification channel includes a primary channel located in the primary high-voltage pulse discharge purification device and a secondary channel located in the secondary high-voltage pulse discharge purification device, and the outlet end of the heating flue, the primary channel and the secondary channel are connected in sequence; The residence time of the flue gas in the primary channel is t1, and the residence time in the secondary channel is t2, satisfying t1≥t2.

3. The municipal sludge incineration flue gas purification system according to claim 2, characterized in that: The municipal sludge incineration flue gas purification system also includes an activated carbon box, a smoke exhaust pipe and a smoke exhaust valve. The activated carbon box and the smoke exhaust pipe are respectively connected to the outlet of the secondary channel, and the smoke exhaust valve is arranged on the smoke exhaust pipe.

4. The municipal sludge incineration flue gas purification system according to claim 1, characterized in that: The two opposite side walls of the heating flue are respectively provided with a plurality of guide plates, and the plurality of guide plates on the two sides are arranged alternately in sequence along the flue gas flow direction; Among them, the inlet end and the outlet end of the heating flue are respectively arranged on both sides of the arrangement direction of the plurality of guide plates.

5. The municipal sludge incineration flue gas purification system according to claim 4, characterized in that: The heating flue is located at the tar storage position of the electrostatic precipitator channel and is connected to two flushing pipes. The two flushing pipes are respectively arranged on both sides of the arrangement direction of the multiple guide plates, and each flushing pipe is provided with a valve, and one of the flushing pipes is used to introduce a flushing solution.

6. The municipal sludge incineration flue gas purification system according to claim 5, characterized in that: One of the two flushing pipes is connected to the heating chamber.

7. The municipal sludge incineration flue gas purification system according to claim 6, characterized in that: The inner wall material of the heating flue is duplex stainless steel.

8. The municipal sludge incineration flue gas purification system according to claim 1, characterized in that: The outlet end of the air passage is used to communicate with the combustion chamber of the incinerator.

9. The municipal sludge incineration flue gas purification system according to claim 1, characterized in that: The smoke inlet pipe includes a main smoke inlet pipe, two smoke inlet branches and two regulating valves. The main smoke inlet pipe is respectively connected to the two smoke inlet branches. One of the two smoke inlet branches is connected to the entrance of the preheating flue, and the other is connected to the entrance of the electrostatic dust removal channel. The two regulating valves are respectively arranged on the two smoke inlet branches.

10. The municipal sludge incineration flue gas purification system according to claim 9, characterized in that: The flue gas flow rate input into the electrostatic precipitator channel is q1, and the flue gas flow rate input into the preheating flue is q2, satisfying 0.15≤q1 / q2≤0.18.

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