An electric furnace device for hazardous waste heat treatment

Abstract

This invention relates to the field of hazardous waste treatment technology, specifically to an electric furnace device for hazardous waste thermal treatment, comprising an electrically heated rotary kiln and a secondary combustion chamber connected to the outlet of the electrically heated rotary kiln. The lower part of the secondary combustion chamber is provided with a cooling water pool and a mixing chamber. A circulating scraping mechanism is provided within the cooling water pool, comprising multiple scrapers and a circulating drive assembly that drives the scrapers in cyclical motion. The scrapers can reciprocate along the bottom of the cooling water pool and the top of the mixing chamber to scrape off the bottom sludge formed by the sedimentation of the bottom ash in the cooling water pool and transport it to the mixing chamber. This device replaces the traditional single-stage, intense cooling method of directly immersing the bottom ash in water with a two-stage cooling structure of "pre-coating and pre-cooling of the bottom sludge + deep final cooling in the water body," thereby reducing the generation of large amounts of dust-laden steam instantaneously from the source and preventing dust-laden steam from flowing back into the secondary combustion chamber under the negative pressure inside the kiln.

Description

Technical Field

[0001] This invention relates to the field of hazardous waste treatment technology, specifically to an electric furnace device for hazardous waste heat treatment. Background Technology

[0002] The complete set of externally heated electric rotary kiln equipment for hazardous waste disposal consists of a sealed airlock feeding unit, an electric-heated rotary kiln body, an independent electric supplementary heating secondary combustion chamber, a bottom ash cooling and discharge system, a complete set of tail gas purification devices, and a PLC automatic control system. The entire process operates under a slight negative pressure in a closed system. Solid and liquid hazardous waste is continuously fed into a slightly inclined 310S heat-resistant steel rotary cylinder through a double-layer airlock screw conveyor. The cylinder is externally equipped with segmented electric heating elements of silicon molybdenum rods / silicon carbide rods and is covered with an insulation layer. The inner wall of the cylinder is welded with lifting plates or differential speed center scrapers to turn the waste. The system relies on indirect heat conduction through the cylinder wall to achieve pyrolysis or high-temperature oxidation of hazardous waste. The kiln head and tail are equipped with fish-scale and nitrogen gas curtain dynamic rotating seals to prevent flue gas leakage. The toxic flue gas generated by decomposition enters the secondary combustion chamber and is maintained at a high temperature of over 850°C for full pyrolysis. The high-temperature bottom ash at the kiln tail falls into the water-cooled settling chamber to form bottom mud, which is discharged through the discharge pipe. The flue gas discharged from the secondary combustion chamber is purified by rapid cooling, bag filter dust collection, activated carbon adsorption, and alkaline spraying before being discharged in compliance with standards. The entire set of equipment can realize the harmless and resource-based continuous treatment of small to medium batches of organic hazardous waste.

[0003] In existing technologies, the high-temperature bottom ash discharged from the kiln tail of a rotary kiln falls directly into the cooling water pool below the secondary combustion chamber, relying on the water to quickly cool the bottom ash. However, direct contact between the high-temperature ash and the water will instantly generate a large amount of water vapor, which carries the fine bottom ash back into the secondary combustion chamber. This not only dilutes the oxygen in the furnace and disrupts the stable combustion conditions of the secondary combustion chamber, but also increases the dust and moisture content of the flue gas, significantly increasing the processing load of the downstream exhaust gas purification system. Therefore, we propose an electric furnace device for the thermal treatment of hazardous waste. Summary of the Invention

[0004] To solve the above-mentioned technical problems, this application provides an electric furnace device for hazardous waste heat treatment, including an electrically heated rotary furnace and a secondary combustion chamber connected to the outlet of the electrically heated rotary furnace. The lower part of the secondary combustion chamber is provided with a cooling water pool and a mixing chamber. The cooling water tank is equipped with a circulating scraping mechanism, which includes multiple scrapers and a circulating drive component that drives the scrapers to circulate. The scrapers can move back and forth along the bottom of the cooling water tank and the top of the mixing chamber to scrape the bottom sludge formed by the sedimentation of the bottom ash in the cooling water tank and transport it to the mixing chamber. The mixing chamber is equipped with a stirring component. The high-temperature bottom ash discharged from the rotary kiln first falls into the mixing chamber. The stirring component is used to mix and coat the high-temperature bottom ash with the bottom mud sent into the mixing chamber to achieve pre-cooling. The pre-cooled ash-mud mixture is transported to the cooling water pool by a scraper for deep water cooling.

[0005] In some embodiments, the circulating drive assembly includes two shafts 1 symmetrically rotatably connected to the bottom of the cooling water tank, with two sprockets symmetrically fixedly connected to the shafts 1; a shaft 2 rotatably connected inside the cooling water tank, with two sprockets symmetrically fixedly connected to the shafts 2; and a shaft 3 rotatably connected inside the cooling water tank, with two sprockets symmetrically fixedly connected to the shafts 3. Chains are correspondingly arranged between the sprockets on the two shafts, shaft one and shaft two and shaft three, and the scraper is fixedly connected to the chain. A reduction motor is provided on the outer wall of the second combustion chamber. The output shaft of the reduction motor is fixedly connected to one end of shaft two. When the reduction motor is started, it drives the scraper to move.

[0006] In some embodiments, the stirring assembly includes a stirring shaft rotatably connected to the mixing chamber, a plurality of stirring blades are uniformly arranged on the stirring shaft, and a plurality of connecting rods are fixedly connected between the stirring blades and the stirring shaft; One end of the stirring shaft passes through the secondary combustion chamber and is rotatably connected to its inner wall. A linkage is provided between the stirring shaft and the secondary shaft to synchronously drive the stirring shaft to rotate when the secondary shaft rotates.

[0007] In some embodiments, the linkage includes an active gear disk fixedly connected to the second shaft, and a passive gear disk meshing with the active gear disk is fixedly connected to one end of the stirring shaft.

[0008] In some embodiments, a flow guide baffle is provided at the bottom of the cooling water tank. The flow guide baffle includes a vertical part parallel to the side wall of the cooling water tank and an arc-shaped part fixedly connected to the mixing chamber, which is used to cooperate with the scraper to transport the bottom sludge into the mixing chamber.

[0009] In some embodiments, the sprocket mounted on the third shaft is arranged below the liquid surface of the cooling water tank, the sprocket mounted on the second shaft is arranged above the liquid surface of the cooling water tank, the chain connecting the two sets of sprockets is arranged at an angle, and the feed opening of the mixing chamber is adapted to the movement trajectory of the chain and scraper and is set to an inclined structure.

[0010] In some embodiments, the bottom of the cooling water pool is connected to a bottom sludge discharge pipe to discharge excess bottom sludge and prevent its accumulation.

[0011] The present invention has at least the following beneficial effects: This device employs a two-stage cooling structure of "pre-cooling by pre-wrapping bottom sludge + deep final cooling in water" to replace the traditional single-stage, intense cooling method of directly immersing bottom ash in water. This fundamentally reduces the generation of large amounts of dust-laden steam instantaneously, preventing dust-laden steam from flowing back into the secondary combustion chamber under negative pressure within the kiln. This effectively stabilizes the combustion conditions in the secondary combustion chamber, ensures the full decomposition of organic matter, and significantly reduces the processing load of the downstream exhaust gas dust removal and deacidification systems, thereby improving the operational stability and environmental treatment effect of the entire hazardous waste heat treatment device. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 For the present invention Figure 1 Schematic diagram of partial cross-section structure; Figure 3 For the present invention Figure 2 Schematic diagram of partial cross-section structure; Figure 4 For the present invention Figure 3 Schematic diagram of partial cross-section structure; Figure 5 This is a schematic diagram of the structure of the flow guide baffle of the present invention.

[0013] In the diagram: 1. Electric heating rotary kiln; 2. Secondary combustion chamber; 3. Cooling water tank; 4. Mixing bin; 5. Circulating scraping mechanism; 6. Scraper; 7. Circulating drive assembly; 8. Agitator assembly; 9. Shaft 1; 10. Sprocket; 11. Shaft 2; 12. Shaft 3; 13. Chain; 14. Gear motor; 15. Agitator shaft; 16. Agitator blades; 17. Connecting rod; 18. Linkage component; 19. Drive gear plate; 20. Driven gear plate; 21. Guide baffle; 22. Vertical section; 23. Arc-shaped section; 24. Bottom mud discharge pipe. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Please see Figures 1-5 This invention provides a technical solution: an electric furnace device for hazardous waste thermal treatment, comprising an electrically heated rotary furnace 1 and a secondary combustion chamber 2 connected to the flue gas outlet of the electrically heated rotary furnace 1. After the electrically heated rotary furnace 1 completes the pyrolysis and oxidative cracking treatment of hazardous waste, the high-temperature flue gas enters the secondary combustion chamber 2 for high-temperature and complete combustion, while the high-temperature bottom ash generated in the furnace is continuously discharged from the tail of the rotary furnace. The lower area of ​​the secondary combustion chamber 2 integrates a cooling water tank 3 and a matching mixing chamber 4. The cooling water tank 3 serves as the final water-cooling and sedimentation area for the high-temperature bottom ash, enabling rapid cooling and solid-liquid sedimentation separation of the ash and slag. This allows the high-temperature bottom ash falling into the water to gradually settle and form a high-concentration wet sludge, providing a stable material source for subsequent pre-cooling processes.

[0016] The cooling water tank 3 is equipped with a circulating scraping mechanism 5, which mainly consists of multiple scraper blades 6 and a circulating drive assembly 7 for providing power. The circulating drive assembly 7 can drive the multiple scraper blades 6 to perform continuous closed-loop circulation, enabling the scraper blades 6 to reciprocate along the bottom of the cooling water tank 3 and the top of the mixing chamber 4. During the movement along the bottom of the tank, the scraper blades 6 can continuously scrape the wet bottom sludge formed by the mixture of high-temperature bottom ash and water at the bottom of the cooling water tank 3, and stably transport the bottom sludge into the mixing chamber 4, realizing the continuous reuse and transportation of the bottom sludge of the tank.

[0017] Mixing chamber 4 is an independent mixing cavity, with a fixed agitator 8 installed inside. The newly discharged high-temperature bottom ash from the tail of the rotary kiln first falls into the mixing chamber 4, where it merges with the low-temperature wet bottom mud conveyed by scraper 6. The agitator 8 can fully mix the high-temperature dry bottom ash and low-temperature wet bottom mud in the chamber, so that the bottom mud evenly coats the surface of the high-temperature bottom ash particles. The bound water and low-temperature solid ash contained in the bottom mud gently pre-cool the high-temperature bottom ash. Compared with the violent heat exchange method of high-temperature bottom ash directly contacting clean water, the bottom mud's bound water does not flow freely for heat exchange, and the heat exchange process is gradual. This can significantly reduce the instantaneous water vapor flash evaporation and effectively avoid the problem of a large amount of steam bursting instantly. At the same time, the bottom mud coating of fine ash can significantly reduce the phenomenon of fine fly ash being carried to the surface by steam.

[0018] After the high-temperature base ash completes the pre-cooling and forms a uniform ash mixture with a significantly reduced temperature, the mixed ash material is transported back into the cooling water tank 3 by the circulating scraper 6, where the water in the tank completes the final deep water cooling.

[0019] This device employs a two-stage cooling structure of "pre-cooling by pre-wrapping bottom sludge + deep final cooling in water" to replace the traditional single-stage, intense cooling method of directly immersing bottom ash in water. This fundamentally reduces the generation of large amounts of dust-laden steam instantaneously, preventing dust-laden steam from flowing back into the secondary combustion chamber 2 under negative pressure within the kiln. This effectively stabilizes the combustion conditions in the secondary combustion chamber 2, ensures the full decomposition of organic matter, and significantly reduces the processing load of the downstream exhaust gas dust removal and deacidification systems, thereby improving the operational stability and environmental treatment effect of the entire hazardous waste heat treatment device.

[0020] The circulating drive assembly 7 includes two shafts 9, a second shaft 11 which serves as the second drive shaft, and a third shaft 12 which serves as the third drive shaft. The two shafts 9 are symmetrically and rotatably mounted on the bottom of the cooling water tank 3, and two sprockets 10 are symmetrically fixed on each shaft 9. The second shaft 11 and the third shaft 12 are rotatably mounted inside the cooling water tank 3, and two sets of sprockets 10 are also symmetrically fixed on the second shaft 11 and the third shaft 12 respectively. The sprocket 10 on shaft 11, which serves as the second drive shaft, is positioned above the liquid surface of the cooling water tank 3. The sprocket 10 on shaft 12, which serves as the third drive shaft, is positioned below the liquid surface of the cooling water tank 3. The chains 13 connecting the sprockets 10 on shafts 11 and 12 are arranged at an angle. Closed-loop chains 13 are tensioned between the corresponding sprockets 10 on shafts 11, 12, and 12. Multiple scrapers 6 are evenly fixed on the chains 13. The feed opening of the mixing chamber 4 is set at an angle to accommodate the movement trajectory of the chains 13 and scrapers 6. A geared motor 14 is installed on the outer wall of the secondary combustion chamber 2. The output end of the geared motor 14 is rigidly connected to the end of shaft 11. When the equipment is running, starting the geared motor 14 drives shaft 11 to rotate. Through the meshing of the sprockets 10 and chains 13, the geared motor 14 drives all chains 13 and scrapers 6 fixed on the chains 13 to move continuously in a cycle. This structure places the second drive shaft sprocket 10 above the water surface and the third drive shaft sprocket 10 below the water surface, so that the chain 13 between the two is in an inclined shape. Combined with the inclined mixing chamber 4 opening adapted to the movement trajectory of the scraper 6, the mixed bottom sediment overflowing from the mixing chamber 4 can be smoothly pushed into the water body.

[0021] The stirring assembly 8 includes a stirring shaft 15 rotatably connected to the mixing chamber 4. Multiple stirring blades 16 are evenly arranged on the stirring shaft 15, and multiple connecting rods 17 are fixedly connected between the stirring blades 16 and the stirring shaft 15. One end of the stirring shaft 15 passes through the secondary combustion chamber 2 and is rotatably connected to its inner wall. A linkage 18 is provided between the stirring shaft 15 and the second shaft 11. The linkage 18 includes an active toothed disc 19 fixedly connected to the second shaft 11. One end of the stirring shaft 15 is fixedly connected to a passive toothed disc 20 that meshes with the active toothed disc 19. When the second shaft 11 rotates, the active toothed disc 19 drives the passive toothed disc 20 to rotate, thereby driving the stirring blades 16 fixedly connected to the stirring shaft 15 to rotate, so as to mix the high-temperature bottom ash and bottom mud.

[0022] The bottom of the cooling water tank 3 is provided with a flow guide baffle 21 that is fixedly connected to the side wall of the cooling water tank 3. The flow guide baffle 21 is composed of a vertical section parallel to the side wall of the cooling water tank 3 and an arc-shaped section fixedly connected to the mixing chamber 4. The flow guide baffle 21 can cooperate with the scraper 6 to guide the bottom mud of the tank to be smoothly transported to the inside of the mixing chamber 4 along the movement path of the scraper 6.

[0023] The bottom of the cooling water tank 3 is connected to a bottom sludge discharge pipe 24, which is used to discharge excess bottom sludge in the water tank and prevent excessive accumulation of bottom sludge.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. An electric furnace device for hazardous waste heat treatment, comprising an electrically heated rotary furnace (1) and a secondary combustion chamber (2) connected to the outlet of the electrically heated rotary furnace (1), characterized in that: The lower part of the secondary combustion chamber (2) is provided with a cooling water pool (3) and a mixing chamber (4); The cooling water tank (3) is equipped with a circulating scraping mechanism (5). The circulating scraping mechanism (5) includes multiple scrapers (6) and a circulating drive assembly (7) that drives the scrapers (6) to move in a circular motion. The scrapers (6) can move back and forth along the bottom of the cooling water tank (3) and the top of the mixing chamber (4) to scrape the bottom sludge formed by the sedimentation of the bottom ash in the cooling water tank (3) and transport it to the mixing chamber (4). The mixing chamber (4) is equipped with a stirring assembly (8). The high-temperature bottom ash discharged from the rotary kiln first falls into the mixing chamber (4). The stirring assembly (8) is used to mix and wrap the high-temperature bottom ash with the bottom mud sent into the mixing chamber (4) to achieve pre-cooling. The pre-cooled ash-mud mixture is transported to the cooling water pool (3) by a scraper (6) for deep water cooling.

2. The electric furnace device for hazardous waste heat treatment according to claim 1, characterized in that: The circulating drive assembly (7) includes two shafts (9) symmetrically rotatably connected to the bottom of the cooling water tank (3). Two sprockets (10) are symmetrically fixedly connected to the shafts (9). A shaft (11) is rotatably connected inside the cooling water tank (3). Two sprockets (10) are also symmetrically fixedly connected to the shafts (11). A shaft (12) is rotatably connected inside the cooling water tank (3). Two sprockets (10) are also symmetrically fixedly connected to the shafts (12). Chains (13) are correspondingly arranged between the sprockets (10) on the two shafts (9) and shafts (11) and (12), and the scraper (6) is fixedly connected to the chain (13). A reduction motor (14) is provided on the outer wall of the secondary combustion chamber (2). The output shaft of the reduction motor (14) is fixedly connected to one end of shaft (11). When the reduction motor (14) is started, it drives the scraper (6) to move.

3. The electric furnace device for hazardous waste heat treatment according to claim 2, characterized in that: The stirring assembly (8) includes a stirring shaft (15) rotatably connected to the mixing chamber (4), and multiple stirring blades (16) are evenly arranged on the stirring shaft (15). Multiple connecting rods (17) are fixedly connected between the stirring blades (16) and the stirring shaft (15). One end of the stirring shaft (15) passes through the secondary combustion chamber (2) and is rotatably connected to its inner wall. A linkage (18) is provided between the stirring shaft (15) and the second shaft (11) to synchronously drive the stirring shaft (15) to rotate when the second shaft (11) rotates.

4. The electric furnace device for hazardous waste heat treatment according to claim 3, characterized in that: The linkage (18) includes an active gear disk (19) fixedly connected to shaft two (11), and a passive gear disk (20) that meshes with the active gear disk (19) is fixedly connected to one end of the stirring shaft (15).

5. The electric furnace device for hazardous waste heat treatment according to claim 4, characterized in that: The bottom of the cooling water tank (3) is provided with a flow guide baffle (21). The flow guide baffle (21) includes a vertical part (22) parallel to the side wall of the cooling water tank (3) and an arc-shaped part (23) fixedly connected to the mixing chamber (4), which is used to cooperate with the scraper (6) to transport the bottom mud into the mixing chamber (4).

6. The electric furnace device for hazardous waste heat treatment according to claim 5, characterized in that: The sprocket (10) mounted on the third shaft (12) is arranged below the liquid surface of the cooling water tank (3), and the sprocket (10) mounted on the second shaft (11) is arranged above the liquid surface of the cooling water tank (3). The chain (13) connecting the two sets of sprockets (10) is arranged at an angle. The feed opening of the mixing chamber (4) is adapted to the movement trajectory of the chain (13) and the scraper (6) and is set to an inclined structure.

7. The electric furnace apparatus for hazardous waste heat treatment according to claim 6, characterized in that: The bottom of the cooling water pool (3) is connected to a bottom mud discharge pipe (24) to discharge excess bottom mud and prevent its accumulation.

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