A mixed garbage incineration system based on household garbage

Abstract

The application discloses a mixed garbage incineration system based on household garbage, which comprises a flue gas main pipe (1) and an air preheater (2), air inlet pipes (3), air outlet pipes (4), flue gas inlet pipes (5) and flue gas outlet pipes (6) are arranged around the air preheater (2) respectively, the flue gas inlet pipes (5) are connected with the flue gas main pipe (1) externally, characterized in that: the flue gas main pipe (1) is sequentially provided with a filtering mechanism (7) and a preheating mechanism (8) along a flue gas conveying direction, a first temperature measuring sensor (9) is arranged between the filtering mechanism (7) and the preheating mechanism (8), backflow pipes (10) and second temperature measuring sensors (11) are arranged on the air outlet pipes (4) respectively, a cold air fan (12) is connected with one end of the preheating mechanism (8), and the other end of the preheating mechanism (8) is connected with the air outlet pipes (4) through the backflow pipes (10). The application has the characteristics of good temperature control effect and high heat energy recovery rate.

Description

Technical Field

[0001] This invention relates to a waste incinerator, and more particularly to a mixed waste incineration system based on municipal solid waste. Background Technology

[0002] To achieve heat recovery and utilization of waste incineration flue gas, manufacturers currently install air preheaters at the rear end of the flue gas duct of the waste incinerator. This allows the flue gas to exchange heat with the outside air during emission, resulting in clean, usable high-temperature air. However, due to the complex and uncontrollable composition of municipal solid waste, the temperature of the incineration flue gas exhibits significant uncertainty, fluctuating randomly within a certain range. This causes the temperature of the high-temperature air after heat exchange with the air preheater to also vary. On the one hand, this is detrimental to the manufacturer's temperature control and subsequent use of the high-temperature air; on the other hand, the fluctuating flue gas temperature makes it difficult for the air preheater to maintain optimal heat exchange efficiency when exchanging heat with flue gas at different temperatures. This can easily lead to a decrease in the heat recovery rate of the flue gas and result in the flue gas failing to reach the required temperature after heat exchange.

[0003] To address the aforementioned shortcomings, manufacturers currently offer two solutions. The first is to install secondary heating equipment on the air outlet pipe or flue gas inlet pipe of the air preheater. This involves using secondary heating equipment to reheat the flue gas or the air after heat exchange, thereby bringing the flue gas or air to the set temperature. However, this method not only incurs additional energy consumption but also, due to frequent fluctuations in flue gas temperature, requires frequent high-power adjustments to the secondary heating equipment. This leads to high equipment load and a high failure rate, increasing the manufacturer's operating and maintenance costs for the secondary heating equipment.

[0004] The second method involves adding an air inlet pipe to the end of the flue gas duct. This inlet pipe controls the amount of outside air entering the duct based on the flue gas temperature, allowing the flue gas and a fixed amount of outside air to mix and reach the set temperature. While this method significantly reduces equipment energy consumption compared to the first, it results in the direct waste of flue gas heat, leading to a significant reduction in heat recovery efficiency.

[0005] Furthermore, the flue gas from municipal solid waste incineration contains a large amount of fly ash, oil droplets, and other impurities, which easily adhere to the surface of the heat exchange tubes in the air preheater during the heat exchange process. Even though existing air preheaters are equipped with cleaning mechanisms to remove these deposits, these mechanisms can only break down and remove hard, brittle ash and scale. They are ineffective at cleaning the sticky, strongly adhesive mixture of fly ash and oil sludge that is tightly bonded to the tube walls. This reduces the heat exchange efficiency of the air preheater for the flue gas and affects the accuracy of temperature control for the heated air.

[0006] Therefore, existing methods for treating flue gas from municipal solid waste incineration suffer from poor temperature control and low heat recovery rates. Summary of the Invention

[0007] The purpose of this invention is to provide a mixed waste incineration system based on municipal solid waste. It features good temperature control and high heat recovery rate.

[0008] The technical solution of the present invention: A mixed waste incineration system based on municipal solid waste, comprising a flue gas main pipe and an air preheater. The air preheater is provided with an air inlet pipe, an air outlet pipe, a flue gas inlet pipe, and a flue gas outlet pipe on its periphery. The flue gas inlet pipe is connected to the flue gas main pipe. The flue gas main pipe is provided with a filtration mechanism and a preheating mechanism in sequence along the flue gas conveying direction. A first temperature sensor is provided between the filtration mechanism and the preheating mechanism. A return pipe and a second temperature sensor are provided on the air outlet pipe. One end of the preheating mechanism is connected to a cold air fan, and the other end of the preheating mechanism is connected to the air outlet pipe via the return pipe.

[0009] The filtration mechanism is used to filter the flue gas;

[0010] The first temperature sensor is used to detect the flue gas temperature and trigger the preheating mechanism when the flue gas temperature reaches the first temperature threshold.

[0011] The cold air fan is used to deliver outside air to the preheating mechanism;

[0012] The preheating mechanism is used to exchange heat between the outside air and the flue gas, so that the temperature of the flue gas drops to a specified temperature range, while the outside air becomes high-temperature air after the heat exchange.

[0013] The air preheater is used to exchange heat between the outside air and the flue gas, so that the outside air becomes high-temperature air after the heat exchange and is discharged to the outside through the air inlet pipe.

[0014] The return pipe is used to transport the high-temperature air after heat exchange, so that the high-temperature air enters the air inlet pipe along the return pipe and mixes with the high-temperature air to form mixed air;

[0015] The second temperature sensor is used to detect the temperature of the mixed air and triggers the cooling fan to increase the intake of outside air when the temperature of the mixed air reaches the second temperature threshold.

[0016] In the aforementioned mixed waste incineration system based on municipal solid waste, the preheating mechanism includes a first flue gas branch pipe and a second flue gas branch pipe arranged in parallel. One end of the first flue gas branch pipe and the second flue gas branch pipe are connected to the main flue gas pipe through a pipe joint, and the other end of the first flue gas branch pipe and the second flue gas branch pipe are connected to the flue gas inlet pipe through a pipe joint. Both ends of the first flue gas branch pipe and the second flue gas branch pipe are connected to a first shut-off valve. A heat exchange tube is provided inside the first flue gas branch pipe. Both ends of the heat exchange tube extend to the outside of the first flue gas branch pipe and are connected to an on / off valve. One end of the heat exchange tube is connected to a cold air fan, and the other end of the heat exchange tube is connected to an air outlet pipe through a return pipe.

[0017] In the aforementioned mixed waste incineration system based on municipal solid waste, there are multiple heat exchange tubes that are spaced apart within the first flue gas branch pipe. Both ends of each heat exchange tube extend to the outside of the first flue gas branch pipe and are connected to on / off valves. One end of the multiple heat exchange tubes is interconnected via a first diversion pipe, and a cold air fan is connected to the outside of the first diversion pipe. The other end of the multiple heat exchange tubes is interconnected via a second diversion pipe, and a return pipe is connected to the outside of the second diversion pipe.

[0018] In the aforementioned mixed waste incineration system based on municipal solid waste, the filtration mechanism includes a filter pipe detachably connected to the flue gas main pipe. Multiple filter screens are spaced apart inside the filter pipe along the flue gas conveying direction. A drive shaft is provided on one side of the filter screen, and multiple scrapers are spaced apart on the drive shaft. One side of each scraper is in contact with a filter screen. A drive motor located outside the filter pipe is connected to one side of the drive shaft via a transmission component. A waste discharge pipe is connected to the bottom of the filter pipe, and a second shut-off valve is connected to the end of the waste discharge pipe near the filter pipe.

[0019] In the aforementioned mixed waste incineration system based on municipal solid waste, the inner walls of both sides of the filter tube are connected with symmetrically distributed locking strips, and the middle of the locking strips forms an installation groove. The two sides of the filter screen are fastened and connected in the installation groove.

[0020] In the aforementioned mixed waste incineration system based on municipal solid waste, the card strips are provided with connecting holes for the drive shaft to pass through. The drive shaft passes through each card strip through the connecting holes and is connected to the scraper. One end of the drive shaft extends to the outside of the card strip and is connected to a cover plate. A compression spring is provided between the cover plate and the card strip and sleeved on the outside of the drive shaft. The compression spring is used to apply axial compressive force to the drive shaft, so that each scraper adheres to the filter screen under the action of compressive force.

[0021] In the aforementioned mixed waste incineration system based on municipal solid waste, pressure taps are provided on the side walls at both ends of the filter tube. Differential pressure sensors are externally connected to the two pressure taps. The differential pressure sensors are used to detect the pressure difference of flue gas before and after the filter screen, and trigger the drive shaft to rotate and clean when the detected pressure difference reaches the first differential pressure threshold.

[0022] In the aforementioned mixed waste incineration system based on municipal solid waste, the scraper is detachably connected to a high-temperature resistant polytetrafluoroethylene (PTFE) plate on the side near the filter screen. The high-temperature resistant PTFE plate has a serrated surface on the side near the filter screen. The scraper is used to scrape off the deposits attached to the surface of the filter screen after the drive shaft rotates.

[0023] Compared with the prior art, the present invention has the following characteristics:

[0024] (1) The present invention, through the structural cooperation of the preheating mechanism and the first temperature sensor, enables the preheating mechanism to be turned on to exchange heat and cool down the flue gas when the flue gas temperature reaches the first temperature threshold, so that the flue gas enters the air preheater at a specified temperature range and air volume after heat exchange, thereby ensuring the heat exchange efficiency and heat exchange effect of the air preheater on the flue gas; by transporting the air after heat exchange to the air outlet pipe through the return pipe, the air can be charged and then the air processed by the air preheater can be cooled down a second time, so that the two reach a specified temperature value after mixing, which effectively improves the temperature control effect of the heat exchange air;

[0025] (2) By limiting the structure of the preheating mechanism and the number of heat exchange tubes, the present invention can also control the number of heat exchange tubes according to the flue gas temperature, thereby improving the temperature control stability of the present invention; on the basis of the above, by cooperating with the second temperature sensor, the present invention can also adjust the speed of the cold air fan based on the temperature of the mixed air, thereby controlling the secondary cooling effect of the flue gas by changing the air intake of the high temperature air, and further improving the temperature control accuracy of the mixed air after two coolings.

[0026] (3) By limiting the structure of the filter mechanism, the filter screen can filter the flue gas as it passes through, so that the fly ash and sludge in the flue gas can be intercepted on the filter screen. That is, the flue gas can be initially filtered without affecting the normal transport of the flue gas, reducing the amount of sticky dust and sludge that adheres to the heat exchange tube and air preheater, and improving the treatment effect and stability of the flue gas of the subsequent equipment.

[0027] (4) By limiting the structure of the scraper, the scraper can periodically remove the deposits on the surface of the filter screen, and the deposits will fall to the outside through the waste discharge pipe after being scraped off, thereby cleaning the surface of the filter screen and preventing the filter screen from being blocked and affecting the normal delivery of exhaust gas; on this basis, by setting up the mounting plate, when the filter screen is severely blocked and cannot be scraped off by the scraper, the filter screen can be manually cleaned or replaced by hand, further ensuring the stability of exhaust gas delivery;

[0028] (5) By coordinating the structure of the drive shaft and the compression spring, on the one hand, the drive shaft can simultaneously drive multiple scrapers to scrape the filter screen; on the other hand, the compression spring can apply a squeezing force toward the filter screen to the scraper, thereby improving the scraping effect of the scraper on the surface of the filter screen under the squeezing action.

[0029] Therefore, the present invention has the characteristics of good temperature control and high heat recovery rate. Attached Figure Description

[0030] Figure 1 These are schematic diagrams of the structures in Embodiments 1 and 3;

[0031] Figure 2 yes Figure 1 A magnified view from direction A;

[0032] Figure 3 yes Figure 1 A magnified view from direction B;

[0033] Figure 4 yes Figure 3 C-axis magnified view;

[0034] Figure 5 yes Figure 3 Sectional view along direction D;

[0035] Figure 6 This is a schematic diagram of the preheating mechanism in Example 2;

[0036] Figure 7 yes Figure 6 Sectional view along direction E;

[0037] Figure 8 This is a schematic diagram of the installation of the first temperature sensor in Example 3;

[0038] Figure 9 yes Figure 8 A magnified view in the F direction;

[0039] Figure 10 yes Figure 8 A magnified view of the G direction.

[0040] The labels in the attached diagram are as follows: 1-Main flue gas pipe, 2-Air preheater, 3-Air inlet pipe, 4-Air outlet pipe, 5-Flue gas inlet pipe, 6-Flue gas outlet pipe, 7-Filtering mechanism, 8-Preheating mechanism, 9-First temperature sensor, 10-Return pipe, 11-Second temperature sensor, 12-Cold air fan, 13-First flue gas branch pipe, 14-Second flue gas branch pipe, 15-First shut-off valve, 16-Heat exchange tube, 17-On / off valve, 18-First branch pipe, 19-Second branch pipe, 20-Filter tube, 21-... 22-Filter screen, 23-Drive shaft, 24-Scraper, 25-Drive motor, 26-Waste discharge pipe, 27-Second sealing valve, 28-Clamping strip, 29-Cover plate, 30-Loading plate, 31-Differential pressure sensor, 32-High temperature resistant PTFE plate, 33-Fixing base, 34-Mounting block, 35-Protective sleeve, 36-Temperature measuring port, 37-Interception surface, 38-Elastic element, 39-Lifting plate, 40-Lifting component, 331-Lower fixed base, 332-Upper fixed base, 351-Bending part. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0042] Example 1. A mixed waste incineration system based on municipal solid waste, comprising the following components: Figure 1-5 As shown, it includes a flue gas main pipe 1 and an air preheater 2. The air preheater 2 is specifically a tubular air preheater. An air inlet pipe 3, an air outlet pipe 4, a flue gas inlet pipe 5, and a flue gas outlet pipe 6 are respectively provided around the air preheater 2. The flue gas inlet pipe 5 is connected to the flue gas main pipe 1. The flue gas main pipe 1 is provided with a filter mechanism 7 and a preheating mechanism 8 in sequence along the flue gas conveying direction. The flue gas inlet pipe 5 and the flue gas main pipe 1 are connected to each other through the preheating mechanism 8. A first temperature sensor 9 is fixed on the side wall of the flue gas main pipe 1 between the filter mechanism 7 and the preheating mechanism 8. A return pipe 10 and a second temperature sensor 11 are respectively provided on the air outlet pipe 4. The second temperature sensor 11 is fixed on the side wall of the air outlet pipe 4. One end of the preheating mechanism 8 is connected to a cold air fan 12, and the other end of the preheating mechanism 8 is connected to the air outlet pipe 4 through the return pipe 10.

[0043] The filtration mechanism 7 is used to filter the flue gas;

[0044] The first temperature sensor 9 is used to detect the flue gas temperature and trigger the preheating mechanism 8 when the flue gas temperature reaches the first temperature threshold.

[0045] The cold air fan 12 is used to deliver outside air to the preheating mechanism 8;

[0046] The preheating mechanism 8 is used to exchange heat between the outside air and the flue gas, so that the temperature of the flue gas drops to a specified temperature range, while the outside air becomes high-temperature air after the heat exchange.

[0047] The air preheater 2 is used to exchange heat between the outside air and the flue gas, so that the outside air becomes high-temperature air after the heat exchange and is discharged to the outside through the air inlet pipe 3.

[0048] The return pipe 10 is used to transport the high-temperature air after heat exchange, so that the high-temperature air enters the air inlet pipe 3 along the return pipe 10 and mixes with the high-temperature air to form mixed air;

[0049] The second temperature sensor 11 is used to detect the temperature of the mixed air, and when the temperature of the mixed air reaches the second temperature threshold, it triggers the cold air fan 12 to increase the intake of external air, so that the mixed air approaches the set temperature range as the intake volume changes.

[0050] The preheating mechanism 8 includes a first flue gas branch pipe 13 and a second flue gas branch pipe 14 arranged in parallel. One end of the first flue gas branch pipe 13 and the second flue gas branch pipe 14 are connected to the main flue gas pipe 1 through a pipe joint, and the other end of the first flue gas branch pipe 13 and the second flue gas branch pipe 14 are connected to the flue gas inlet pipe 5 through a pipe joint. Both ends of the first flue gas branch pipe 13 and the second flue gas branch pipe 14 are connected to a first shut-off valve 15. The first shut-off valve 15 can be a high-temperature resistant baffle valve or a flap valve. A heat exchange tube 16 is provided inside the first flue gas branch pipe 13. The middle part of the heat exchange tube 16 is arranged in an S-shape inside the first flue gas branch pipe 13. Both ends of the heat exchange tube 16 extend to the outside of the first flue gas branch pipe 13 and are connected to an on / off valve 17. The on / off valve 17 can be an electric ball valve. One end of the heat exchange tube 16 is connected to a cold air fan 12, and the other end of the heat exchange tube 16 is connected to an air outlet pipe 4 through a return pipe 10.

[0051] After heat exchange through heat exchange tube 16, the temperature of high-temperature air 1 is controlled to be lower than that of high-temperature air 2. After heat exchange tube 16 is turned on, a shut-off threshold is set. When the temperature of the shut-off threshold is lower than the first temperature threshold, when the first temperature sensor 9 detects that the flue gas is lower than the shut-off threshold, the preheating mechanism 8 is controlled to shut off heat exchange tube 16, so that the flue gas is transported along the second flue gas branch pipe 14.

[0052] The end of the heat exchange tube 16 is connected to the on / off valve 17 via a heat insulation flange. The heat insulation flange is used to isolate the on / off valve 17 and the heat exchange tube 16 to prevent heat from being directly transferred to the on / off valve 17 via the heat exchange tube 16.

[0053] The filtration mechanism 7 includes a filter pipe 20 detachably connected to the flue gas main pipe 1. The filter pipe 20 has a rectangular cross-section. Multiple filter screens 21 are spaced apart inside the filter pipe 20 along the flue gas conveying direction. The filter screens 21 can be made of 310S heat-resistant stainless steel mesh. A drive shaft 22 is provided on one side of the filter screen 21. The drive shaft 22 and the filter screen 21 are arranged perpendicularly to each other. Multiple scrapers 23 are spaced apart on the drive shaft 22. One side of each scraper 23 is in contact with a filter screen 21. A drive motor 24 located outside the filter pipe 20 is connected to one side of the drive shaft 22 via a transmission assembly. A waste discharge pipe 25 is connected to the bottom of the filter pipe 20. A second shut-off valve 26 is connected to the end of the waste discharge pipe 25 near the filter pipe 20. The second shut-off valve 26 can be a high-temperature resistant flap valve. The lower end of the waste discharge pipe 25 is connected to a waste recycling and processing device.

[0054] Figure 3 This is a diagram showing the state of the scraper 23 in this embodiment when it is rotated to a horizontal position. Figure 5 This is a diagram showing the state of the scraper 23 in this embodiment when it is rotated to the vertical position. The scraper 23 scrapes the main flow area of ​​the filter screen 21 each time it moves. The residue on the edge of the filter screen 21 is removed by the operator during manual cleaning.

[0055] The inner walls of both sides of the filter tube 20 are connected with symmetrically distributed retaining strips 27. The middle of the retaining strip 27 forms an installation groove, and the bottom of the retaining strip 27 is provided with a base plate to support the filter screen plate 21. The two sides of the filter screen plate 21 are fastened and connected in the installation groove.

[0056] The clip 27 is provided with a connecting hole for the drive shaft 22 to pass through. The drive shaft 22 passes through each clip 27 through the connecting hole and is connected to the scraper 23. The drive shaft 22 and the connecting hole are connected to each other by a self-lubricating high-temperature resistant bearing. After installation, the drive shaft 22 and the filter screen plate 21 are vertically staggered along the height direction of the clip 27. The upper ends of both sides of the filter screen plate 21 form stepped openings to avoid the drive shaft 22.

[0057] One end of the drive shaft 22 extends to the outside of the clip 27 and is connected to a cover plate 28. A compression spring 29 is provided between the cover plate 28 and the clip 27 and sleeved on the outside of the drive shaft 22. The compression spring 29 is made of heat-resistant stainless steel and is used to apply axial compressive force to the drive shaft 22 so that each scraper 23 adheres to the filter screen plate 21 under the action of compressive force.

[0058] The transmission assembly includes a first drive gear fixedly connected to the drive shaft 22, a second drive gear provided outside the first drive gear, the first drive gear and the second drive gear meshing with each other, and a drive motor 24 connected to the outside of the second drive gear.

[0059] When in use, the drive shaft 22 will experience slight axial movement under the compression of the compression spring 29. The length of the first drive gear can be set to be greater than that of the second drive gear as needed, so as to avoid the drive shaft 4 from being dislodged or misaligned due to axial movement.

[0060] The first drive gear and the second drive gear are located on the inner and outer sides of the filter tube 20, respectively. The filter tube 20 is provided with a drive port that engages with the first drive gear and the second drive gear. One end of the first drive gear extends through the drive port to the outer side of the filter tube 20 and meshes with the second drive gear.

[0061] The outer side of the drive port is provided with a protective cover for bolted connection of the filter tube 20. The motor shaft of the drive motor 24 extends into the first heat insulation layer and is connected to the second drive gear. The motor shaft of the drive motor 24 and the protective cover are sealed by a sealing ring to prevent gas from escaping. The top of the filter tube 20 forms a loading and unloading port, and the loading and unloading port is provided with a loading and unloading plate 30 for bolted connection of the filter tube 20.

[0062] Pressure taps are provided on the side walls at both ends of the filter tube 20. Anti-clogging sampling tubes are installed at the pressure taps to prevent blockage. Differential pressure sensors 31 are externally connected to the two pressure taps. The differential pressure sensors 31 are used to detect the pressure difference of flue gas before and after the filter plate 21. When the pressure difference reaches the first differential pressure threshold, the drive shaft 22 is triggered to rotate and clean. When the pressure difference reaches the second preset threshold, the staff is notified to clean manually.

[0063] The scraper 23 is detachably connected to a high-temperature resistant polytetrafluoroethylene plate 32 on the side near the filter screen plate 21. The high-temperature resistant polytetrafluoroethylene plate 32 has a serrated surface on the side near the filter screen plate 21. The scraper 23 is used to scrape off the deposits on the surface of the filter screen plate 21 after the drive shaft 22 rotates, and to alleviate the frictional damage to the filter screen plate 21.

[0064] The scraper 23 is provided with reinforcing ribs on the side away from the high-temperature resistant polytetrafluoroethylene plate 32, and the scraper 23 is reinforced by the reinforcing ribs to alleviate the bending deformation of the scraper 23 during operation.

[0065] Each of the pipes is wrapped with a heat insulation layer, which provides heat insulation and protection, reducing heat loss of flue gas and air during the flow process. Thermal expansion gaps are reserved during the installation of the above components to prevent deformation, jamming or damage to the structural components caused by thermal expansion and contraction.

[0066] In this embodiment, the flue gas generated by waste incineration first enters the filter pipe 20 along the flue gas main pipe 1, and then passes through each filter screen plate 21 in sequence along the filter pipe 20, so that the filter screen plate 21 can intercept some impurities such as fly ash and oil droplets in the flue gas, thereby reducing the amount of impurities adhering to the surface of the heat exchange tube 16 and the air preheater 2 when exchanging heat with the flue gas in the future, that is, improving the stability and heat exchange effect of the heat exchange device.

[0067] When the differential pressure sensor 31 detects that the gas pressure difference before and after the filter screen 21 reaches the first preset threshold, it indicates that the filter screen 21 is blocked and affecting the normal flow of flue gas. At this time, the drive motor 24 drives the drive shaft 22 to rotate via the transmission assembly, and the scrapers 23 on the drive shaft 22 scrape off the sticky deposits adhering to the surface of the filter screen 21 as it rotates, thereby cleaning the filter screen 21. When the waste incineration is completed or the waste incinerator is shut down, the second sealing valve 26 opens and allows the fallen deposits to fall into the waste discharge pipe 25, thus facilitating the manufacturer's collection and treatment of impurities.

[0068] When the differential pressure sensor 31 detects that the gas pressure difference before and after the filter screen plate 21 reaches the second preset threshold, it indicates that the filter screen plate 21 is severely blocked and the attached material cannot be scraped off normally by the scraper 23. At this time, the differential pressure sensor 31 issues an alarm, and the operator opens the loading and unloading plate to manually clean the filter screen plate 21 when the waste incinerator is not in operation. The operator can also clean the high-temperature resistant polytetrafluoroethylene plate 32, the sealing plate of the second shut-off valve 26, and other components according to the on-site conditions.

[0069] After passing through the filter mechanism 7, the flue gas flows along the main flue gas pipe 1 towards the preheating mechanism 8, and the flue gas temperature is detected by the first temperature sensor 9 during the flow. When the flue gas temperature does not reach the first temperature threshold, the first shut-off valve 15 of the first flue gas branch pipe 13 is closed and the first shut-off valve 15 of the second flue gas branch pipe 14 is opened, allowing the flue gas to flow along the second flue gas branch pipe 14 to the flue gas inlet pipe 5, i.e., without passing through the heat exchange tube 16. When the flue gas temperature is higher than the first temperature threshold, the first shut-off valve 15 of the first flue gas branch pipe 13 is opened and the first shut-off valve 15 of the second flue gas branch pipe 14 is closed, allowing the flue gas to enter the flue gas inlet pipe 5 through the first flue gas branch pipe 13. When the flue gas passes through the first flue gas branch pipe 13, the cold air fan 12 blows the outside air into the heat exchange tube 16 to exchange heat with the flue gas, thereby realizing the heat exchange and cooling functions of the flue gas. After heat exchange, the flue gas enters the air preheater 2 at a stable temperature range. At the same time, the air in the heat exchange tube 16 forms high-temperature gas after heat exchange and flows through the return pipe 10 to the air outlet pipe 4.

[0070] After the flue gas enters the air preheater 2, it undergoes secondary heat exchange with the air inside the preheater 2, causing the air to form high-temperature gas 2 after heat exchange and be discharged outwards through the air outlet pipe 4. High-temperature gas 2 mixes with high-temperature gas 1 after entering the air outlet pipe 4 to form mixed air. This allows the high-temperature gas 1 to cool the high-temperature gas 2 twice, keeping the mixed air within a set temperature range. Furthermore, the second temperature sensor 11 can detect the temperature of the mixed air and control the speed of the cooling fan 12 and the airflow through the heat exchange pipe 16 based on the air temperature. This allows for fine-tuning of the mixed air temperature using the temperature and airflow of high-temperature gas 1, improving the temperature control effect.

[0071] Example 2. A mixed waste incineration system based on municipal solid waste, configured as follows: Figure 6-7 As shown, it includes a flue gas main pipe 1 and an air preheater 2. The air preheater 2 is provided with an air inlet pipe 3, an air outlet pipe 4, a flue gas inlet pipe 5, and a flue gas outlet pipe 6 around its perimeter. The flue gas inlet pipe 5 is connected to the flue gas main pipe 1. The flue gas main pipe 1 is provided with a filter mechanism 7 and a preheating mechanism 8 in sequence along the flue gas conveying direction. The structure and function of the filter mechanism 7 are the same as in Embodiment 1. The structure of the preheating mechanism 8 is the same as in Embodiment 1 except for the heat exchange tube 16.

[0072] The number of heat exchange tubes 16 is three and they are spaced apart in the first flue gas branch pipe 13. Both ends of each heat exchange tube 16 extend to the outside of the first flue gas branch pipe 13 and are connected to the on / off valve 17. One end of the three heat exchange tubes 16 is connected to each other through the first branch pipe 18. The outside of the first branch pipe 18 is connected to the cold air fan 12. The other ends of the multiple heat exchange tubes 16 are connected to each other through the second branch pipe 19. The outside of the second branch pipe 19 is connected to the return pipe 10.

[0073] The end of the heat exchange tube 16 is connected to the on / off valve 17 via a heat insulation flange.

[0074] Compared to Example 1, this example increases the number of heat exchange tubes 16 to three, allowing the opening degree of the heat exchange tubes 16 to be adjusted according to the flue gas temperature, thereby improving the cooling efficiency and temperature control range of the flue gas. Simultaneously, the heat exchange tubes 16 in the closed state can be sealed by the on / off valve 17, thus preventing continuous heat consumption within the heat exchange tubes 16 and reducing heat loss of the flue gas during the heat exchange process.

[0075] Example 3. A mixed waste incineration system based on municipal solid waste, configured as follows: Figure 1 , 8As shown in Figures 9 and 10, the device includes a main flue gas pipe 1 and an air preheater 2. The air preheater 2 is specifically a tubular air preheater. An air inlet pipe 3, an air outlet pipe 4, a flue gas inlet pipe 5, and a flue gas outlet pipe 6 are respectively provided around the air preheater 2. The flue gas inlet pipe 5 is connected to the main flue gas pipe 1. The main flue gas pipe 1 is provided with a filter mechanism 7 and a preheating mechanism 8 in sequence along the flue gas conveying direction. The flue gas inlet pipe 5 and the main flue gas pipe 1 are connected to each other through the preheating mechanism 8. A first temperature sensor 9 is fixed on the side wall of the main flue gas pipe 1 between the filter mechanism 7 and the preheating mechanism 8. A return pipe 10 and a second temperature sensor 11 are respectively provided on the air outlet pipe 4. The second temperature sensor 11 is fixed on the side wall of the air outlet pipe 4. One end of the preheating mechanism 8 is connected to a cold air fan 12, and the other end of the preheating mechanism 8 is connected to the air outlet pipe 4 through the return pipe 10.

[0076] The structure and function of the filtration mechanism 7 and the preheating mechanism 8 are the same as those in Embodiment 1. The first temperature sensor 9 is connected to the flue gas main pipe 1 through a protection component, and the second temperature sensor 11 is connected to the air outlet pipe 4 through a protection component.

[0077] The protective assembly includes a mounting base 33 fixedly connected to the outer wall of the flue gas main pipe 1 or the air outlet pipe 4. A mounting cavity is formed in the middle of the mounting base 33, and a mounting block 34 and a protective sleeve 35 are respectively provided within the mounting cavity. One end of the protective sleeve 35 is connected to the mounting cavity via a stepped portion, and the other end of the protective sleeve 35 passes through the mounting base 33 and has a temperature measuring port 36 located inside the flue gas main pipe 1. The opening direction of the temperature measuring port 36 is perpendicular to the length direction of the flue gas main pipe 1, and one side of the temperature measuring port 36 forms a smoke-facing side. The protective sleeve 35 is located on the smoke-facing side. An interception surface 37 is formed; the middle part of the mounting block 34 is threadedly connected to the first temperature sensor 9 or the second temperature sensor 11, the wiring terminal of the first temperature sensor 9 or the second temperature sensor 11 passes through the fixing base 33 and extends to the outside of the flue gas main pipe 1, and the temperature measuring end of the first temperature sensor 9 or the second temperature sensor 11 passes through the protective sleeve 35 and extends into the temperature measuring port 36; the interception surface 37 is used to shield the temperature measuring end of the temperature sensor to prevent sticky deposits in the flue gas from directly adhering to the temperature measuring end.

[0078] The side facing the smoke is the front side of the protective sleeve 35 along the direction of smoke flow.

[0079] The protective sleeve 35 below the temperature measuring port 36 is provided with a scraping port; the mounting block 34 is slidably connected in the mounting cavity, and an elastic element 38 is provided between the mounting block 34 and the protective sleeve 35. The elastic element 38 can be a compression spring, a disc spring or a wave spring. The elastic element 38 is used to squeeze and limit the mounting block 34, so that the temperature measuring end of the temperature sensor is axially separated from the scraping port under the squeezing action.

[0080] The fixing seat 33 includes a lower fixing seat 331 and an upper fixing seat 332. The lower fixing seat 331 is fixedly connected to the outer wall of the flue gas main pipe 1. The lower fixing seat 331 and the upper fixing seat 332 are detachably connected. The mounting cavity is formed by the lower fixing seat 331 and the upper fixing seat 332 and is located at the connection between the two.

[0081] The protective sleeve 35 has a bent portion 351 at its end. There are multiple bent portions 351 distributed in a ring around the protective sleeve 35. Adjacent bent portions 351 are separated from each other by U-shaped grooves. The ends of the multiple bent portions 351 form a scraping opening for scraping off the surface of the temperature measuring end after they are closed. The bent portion 351 can be forced to unfold outward after the temperature measuring end is inserted and scrape off the surface of the temperature measuring end, thereby removing the sticky adhering substances on the surface of the temperature measuring end.

[0082] One end of the mounting block 34 extends to the outside of the fixed base 33 and is connected to a lifting plate 39. A lifting component 40 is connected to the outside of the lifting plate 39. The lifting component 40 can be an electric push rod. The lifting component 40 is used to apply axial extrusion force to the mounting block 34, so that the temperature measuring end slides axially relative to the scraping port under the extrusion force, and the scraping port scrapes off the adhering material on the surface of the temperature measuring end as it slides.

[0083] The lower end of the electric push rod is connected to a mounting bracket, which can be fixed to the heat insulation layer with self-tapping screws.

[0084] The upper fixed seat 332 is provided with a stepped hole that connects to the mounting cavity. One end of the mounting block 34 extends through the stepped hole to the outside of the upper fixed seat 332 and is connected to the lifting plate 39. The middle part of the mounting block 34 is in contact with the upper fixed seat 332 on the top surface of the mounting cavity via the stepped surface.

[0085] A clearance is provided between the above components to accommodate thermal expansion. A first sealing ring is provided between the lower fixing seat 331 and the upper fixing seat 332, and a second sealing ring is provided between the upper fixing seat 332 and the mounting block 34.

[0086] Based on Embodiment 1, this embodiment installs the first temperature sensor 9 and the second temperature sensor 11 on the flue gas main pipe 1 and the air outlet pipe 4 via a protection assembly. This allows the protection assembly to shield and protect the temperature measuring ends of the first temperature sensor 9 and the second temperature sensor 11, reducing the adhesion and scaling of sticky substances in the flue gas to the measuring ends. During operation, the temperature measuring ends can detect the flue gas temperature through the temperature measuring ports 36 on both sides, thereby ensuring the temperature measuring effect.

[0087] During continuous temperature measurement, the first temperature sensor 9 and the second temperature sensor 11 retract and quickly reset at specified time intervals, so that the mounting block 34 can drive the temperature measuring end to slide downward along the axial direction of the protective sleeve 35 when the lifting component 40 retracts. The scraping port at the end of the protective sleeve 35 scrapes off the adhering substances on the surface of the temperature measuring end as it slides, thereby improving the temperature measurement stability of the temperature measuring end.

Claims

1. A mixed waste incineration system based on municipal solid waste, comprising a flue gas main pipe (1) and an air preheater (2), wherein the air preheater (2) is provided with an air inlet pipe (3), an air outlet pipe (4), a flue gas inlet pipe (5), and a flue gas outlet pipe (6) around its perimeter, and the flue gas inlet pipe (5) is externally connected to the flue gas main pipe (1), characterized in that: The flue gas main pipe (1) is provided with a filter mechanism (7) and a preheating mechanism (8) in sequence along the flue gas conveying direction. A first temperature sensor (9) is provided between the filter mechanism (7) and the preheating mechanism (8). A return pipe (10) and a second temperature sensor (11) are provided on the air outlet pipe (4). One end of the preheating mechanism (8) is connected to a cold air fan (12), and the other end of the preheating mechanism (8) is connected to the air outlet pipe (4) through the return pipe (10). The filtration mechanism (7) is used to filter the flue gas; The first temperature sensor (9) is used to detect the flue gas temperature and trigger the preheating mechanism (8) to operate when the flue gas temperature reaches the first temperature threshold. The cold air fan (12) is used to deliver outside air to the preheating mechanism (8); The preheating mechanism (8) is used to exchange heat between the outside air and the flue gas, so that the temperature of the flue gas drops to a specified temperature range, while the outside air forms high-temperature air after heat exchange; The air preheater (2) is used to exchange heat between the outside air and the flue gas, so that the outside air becomes high temperature air after heat exchange and is discharged to the outside through the air inlet pipe (3); The return pipe (10) is used to transport the high-temperature air after heat exchange, so that the high-temperature air enters the air inlet pipe (3) along the return pipe (10) and mixes with the high-temperature air to form mixed air; The second temperature sensor (11) is used to detect the temperature of the mixed air and trigger the cold air fan (12) to increase the intake of external air when the temperature of the mixed air reaches the second temperature threshold.

2. The mixed waste incineration system based on municipal solid waste according to claim 1, characterized in that: The preheating mechanism (8) includes a first flue gas branch pipe (13) and a second flue gas branch pipe (14) arranged in parallel. One end of the first flue gas branch pipe (13) and the second flue gas branch pipe (14) is connected to the main flue gas pipe (1) through a pipe joint. The other end of the first flue gas branch pipe (13) and the second flue gas branch pipe (14) is connected to the flue gas inlet pipe (5) through a pipe joint. Both ends of the first flue gas branch pipe (13) and the second flue gas branch pipe (14) are connected to a first shut-off valve (15). A heat exchange tube (16) is provided inside the first flue gas branch pipe (13). Both ends of the heat exchange tube (16) extend to the outside of the first flue gas branch pipe (13) and are connected to an on / off valve (17). One end of the heat exchange tube (16) is connected to a cold air fan (12), and the other end of the heat exchange tube (16) is connected to an air outlet pipe (4) through a return pipe (10).

3. The mixed waste incineration system based on municipal solid waste according to claim 2, characterized in that: The heat exchange tubes (16) are multiple and spaced apart in the first flue gas branch pipe (13). Both ends of each heat exchange tube (16) extend to the outside of the first flue gas branch pipe (13) and are connected to the on / off valve (17). One end of the multiple heat exchange tubes (16) is connected to each other through the first branch pipe (18). The outside of the first branch pipe (18) is connected to the cold air fan (12). The other end of the multiple heat exchange tubes (16) is connected to each other through the second branch pipe (19). The outside of the second branch pipe (19) is connected to the return pipe (10).

4. A mixed waste incineration system based on municipal solid waste according to claim 1, characterized in that: The filtration mechanism (7) includes a filter tube (20) detachably connected to the flue gas main pipe (1). Multiple filter screens (21) are spaced apart inside the filter tube (20) along the flue gas conveying direction. A drive shaft (22) is provided on one side of the filter screen (21). Multiple scrapers (23) are spaced apart on the drive shaft (22). One side of each scraper (23) is in contact with a filter screen (21). A drive motor (24) located outside the filter tube (20) is connected to one side of the drive shaft (22) via a transmission assembly. A waste discharge pipe (25) is connected to the bottom of the filter tube (20). A second shut-off valve (26) is connected to the end of the waste discharge pipe (25) near the filter tube (20).

5. A mixed waste incineration system based on municipal solid waste according to claim 4, characterized in that: The inner walls of both sides of the filter tube (20) are connected with symmetrically distributed clips (27), and the middle of the clips (27) forms an installation groove. The two sides of the filter screen (21) are fastened and connected in the installation groove.

6. A mixed waste incineration system based on municipal solid waste according to claim 5, characterized in that: The card strip (27) is provided with a connecting hole for the drive shaft (22) to pass through. The drive shaft (22) passes through each card strip (27) through the connecting hole and is connected to the scraper (23). One end of the drive shaft (22) extends to the outside of the card strip (27) and is connected to a cover plate (28). A compression spring (29) is provided between the cover plate (28) and the card strip (27) and is sleeved on the outside of the drive shaft (22). The compression spring (29) is used to apply axial compressive force to the drive shaft (22) so that each scraper (23) adheres to the filter screen plate (21) under the compressive force.

7. A mixed waste incineration system based on municipal solid waste according to claim 4, characterized in that: Pressure taps are provided on the side walls at both ends of the filter tube (20), and differential pressure sensors (31) are connected to the outside of the two pressure taps. The differential pressure sensors (31) are used to detect the pressure difference of flue gas before and after the filter screen (21), and trigger the drive shaft (22) to rotate and clean when the pressure difference reaches the first differential pressure threshold.

8. A mixed waste incineration system based on municipal solid waste according to claim 4, characterized in that: The scraper (23) is detachably connected to a high-temperature resistant polytetrafluoroethylene plate (32) on the side near the filter screen (21). The high-temperature resistant polytetrafluoroethylene plate (32) forms a serrated surface on the side near the filter screen (21). The scraper (23) is used to scrape off the deposits on the surface of the filter screen (21) through the high-temperature resistant polytetrafluoroethylene plate (32) after the drive shaft (22) rotates.

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