Organic contaminated soil thermal desorption system and treatment device

Abstract

The application discloses a kind of organic contaminated soil thermal desorption system and processing device, including volatile organic compounds thermal desorption mechanism, oxygen carrier particle recovery mechanism, organic gas attachment gasification reaction mechanism and waste heat recovery mechanism, volatile organic compounds desorption mechanism is used to gasify and remove volatile organic compounds in soil, volatile organic compounds desorption mechanism side is provided with the oxygen carrier particle recovery mechanism for recovering oxygen carrier particle, the side of oxygen carrier particle recovery mechanism is provided with the organic gas attachment gasification reaction mechanism for the gasification reaction of volatile organic compounds.The organic contaminated soil thermal desorption system and processing device provided by the application directly heats organic contaminated soil using solid heat source, which improves the heating effect on one hand and obtains higher concentration of volatile and semi-volatile organic compounds on the other hand, avoiding the dilution of organic gas caused by conventional gas combustion heating, effectively reducing the treatment cost of unit soil.

Description

Technical Field

[0001] This invention relates to the field of deep soil treatment technology, and in particular to a thermal desorption system and treatment device for organically contaminated soil. Background Technology

[0002] With the development of industry and agriculture, the acceleration of urbanization, and the adjustment of industrial structure, a large number of polluting enterprises involved in chemical, metallurgical, petroleum, transportation, and light industries have been relocated or closed. Many of the sites left behind by these relocated industrial enterprises contain volatile organic pollutants in their soil. During the redevelopment process, the volatile and semi-volatile pollutants in the soil can enter other environmental media through the gas-soil cycle and water-soil cycle, or directly enter the human body through the food chain or human respiration, endangering human health.

[0003] Thermal desorption technology has been widely used to remediate soil contaminated with volatile / semi-volatile organic compounds (VOCs). Heating the soil to 300-600℃ can effectively remove pollutants such as benzene compounds, pesticides, polycyclic aromatic hydrocarbons (PAHs), and non-chlorinated VOCs. However, improving the energy utilization efficiency of thermal desorption systems, increasing the treatment efficiency of organically contaminated soil, and reducing the treatment cost per unit of soil are significant technical bottlenecks hindering the widespread application of this technology.

[0004] Currently, there are two main types of thermal desorption systems for organically contaminated soil. One is the direct thermal desorption system, which uses hot flue gas (heat usually comes from the combustion of natural gas) to directly heat the soil to a specified temperature. The advantage of this method is that the soil is in direct contact with the hot flue gas, resulting in high heat exchange efficiency. However, because the desorbed organic pollutants directly enter the flue gas, it significantly increases the volume and difficulty of treating the exhaust gas, thus increasing treatment costs. The other type is the indirect thermal desorption system, which indirectly heats the soil through sleeves or hollow blades. Its advantage is that it reduces the volume and difficulty of treating the exhaust gas. However, because soil is a poor conductor of heat, its heat exchange efficiency is low. Furthermore, the hollow blades, in contact with the soil during rotation, experience severe wear and tear, leading to a high failure rate. In addition, existing thermal desorption systems often use standalone soil heating equipment, implementing the entire process of soil drying, heating, desorption of strongly volatile organic compounds (VOCs), and desorption of weakly VOCs (VOCs) within a single device. This makes it impossible to achieve graded control and optimization of each process to adapt to differences in soil characteristics. Summary of the Invention

[0005] Therefore, it is necessary to provide a thermal desorption system and treatment device for organic polluted soil to address the above-mentioned technical problems. This system uses a solid heat source to directly heat the organic polluted soil, which improves the heating effect and obtains a higher concentration of volatile and semi-volatile organic compounds. This avoids the dilution of organic gases caused by conventional gas combustion heating and effectively reduces the treatment cost per unit of soil.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A thermal desorption system and treatment device for organic polluted soil, which is applied to the thermal desorption of organic polluted soil.

[0008] The organic polluted soil thermal desorption system and treatment device specifically includes a volatile organic compound thermal desorption mechanism, an oxygen carrier particle recovery mechanism, an organic gas attachment and gasification reaction mechanism, and a waste heat recovery mechanism. The volatile organic compound desorption mechanism is used to gasify and remove volatile organic compounds from the soil. An oxygen carrier particle recovery mechanism is provided on one side of the volatile organic compound desorption mechanism for recovering oxygen carrier particles. An organic gas attachment and gasification reaction mechanism is provided on one side of the oxygen carrier particle recovery mechanism for performing a gasification reaction on volatile organic compounds. A waste heat recovery mechanism is provided at the upper end of the volatile organic compound desorption mechanism for recovering waste heat.

[0009] The volatile organic compound (VOC) removal mechanism includes a first drum screen, a first conveyor belt, a first screw feeder, a first rotary kiln, a second rotary kiln, a second drum screen, a slag discharge valve, and a gas conveying assembly. The first conveyor belt is located at the bottom of the first drum screen, and the first screw feeder is located on the side of the first conveyor belt away from the first drum screen. The first rotary kiln is located at the bottom of the first screw feeder, and the second rotary kiln is located at the output end of the first rotary kiln. The second drum screen is fixedly connected to the output end of the second rotary kiln, and the slag discharge valve is connected to the side of the second drum screen away from the second rotary kiln via a pipe. The screen hole diameter of the first drum screen is 10 cm.

[0010] In a preferred embodiment of the organic polluted soil thermal desorption system and treatment device provided by the present invention, the gas conveying assembly includes a first gas outlet, a second gas outlet, a partition wall heat exchanger, a first gas inlet, a second gas inlet, and a sixth gas outlet. The top surface of the first rotary kiln is fixedly connected to the first gas outlet, and the top surface of the second rotary kiln is fixedly connected to the second gas outlet. A partition wall heat exchanger is provided at the upper end of the first and second rotary kilns. The bottom surface of the partition wall heat exchanger is fixedly connected to the first gas inlet, and the bottom surface of the partition wall heat exchanger is fixedly connected to the second gas inlet. A condenser is provided in the middle of the first rotary kiln and the partition wall heat exchanger. The two ends of the condenser are respectively connected to the middle of the first gas outlet and the first gas inlet through pipes. The second gas outlet is connected to the middle of the second gas inlet through a pipe. The top surface of the partition wall heat exchanger is fixedly connected to the sixth gas outlet.

[0011] As a preferred embodiment of the organic polluted soil thermal desorption system and treatment device provided by the present invention, the oxygen carrier particle recovery mechanism includes a second conveyor belt, a second screw feeder, a lifting pipe, and a cyclone separator. The bottom end of the second drum screen is provided with a second conveyor belt, and the bottom end of the second conveyor belt is provided with a second screw feeder. The end of the second screw feeder away from the second conveyor belt is fixedly connected to the lifting pipe, and the end of the lifting pipe away from the second screw feeder is fixedly connected to the cyclone separator.

[0012] In a preferred embodiment of the organic polluted soil thermal desorption system and treatment device provided by the present invention, a second air blower is provided in the middle of the riser pipe, a natural gas heater is provided in the middle of the riser pipe, the second air blower is provided at the upper end of the natural gas heater, a first inlet is fixedly connected to the surface of the cyclone separator, a third gas outlet is fixedly connected to the top surface of the cyclone separator, and the riser pipe is fixedly connected to the cyclone separator through the first inlet.

[0013] As a preferred embodiment of the organic polluted soil thermal desorption system and treatment device provided by the present invention, the gasification reaction mechanism includes a moving bed reactor, a fourth gas outlet and a fifth gas outlet. The moving bed reactor is fixedly connected to the bottom end of the cyclone separator. The end of the moving bed reactor away from the cyclone separator is fixedly connected to the input end of the first rotary kiln. The fourth gas outlet and the fifth gas outlet are opened on the surface of the moving bed reactor.

[0014] In a preferred embodiment of the organic polluted soil thermal desorption system and treatment device provided by the present invention, the sixth gas outlet is connected to the moving bed reactor and the fourth gas outlet on the surface of the moving bed reactor via a pipeline.

[0015] In a preferred embodiment of the organic polluted soil thermal desorption system and treatment device provided by the present invention, the waste heat recovery mechanism includes a first induced draft fan, a second induced draft fan, a first air blower, and a waste heat recovery device. A first air blower is installed on one side of the cyclone separator. The first air blower is connected to a moving bed reactor via a pipeline. A first induced draft fan is installed on one side of the moving bed reactor. The third, fourth, and fifth gas outlets are connected to the input end of the first induced draft fan via pipelines. The output end of the first induced draft fan is connected to the input end of a partition wall heat exchanger via a pipeline. The output end of the partition wall heat exchanger is connected to the waste heat recovery device via a pipeline. The output end of the waste heat recovery device is connected to the output end of the first air blower via a pipeline. A three-way valve is installed between the partition wall heat exchanger and the waste heat recovery device. The input end of the second induced draft fan is connected to the partition wall heat exchanger via a pipeline and the three-way valve. The output end of the second induced draft fan is connected to a riser pipe via a pipeline.

[0016] A thermal desorption treatment device for organic polluted soil, applied to any of the organic polluted soil thermal desorption systems according to claim 1, comprising a moving bed reactor;

[0017] The moving bed reactor includes an external fixed sleeve, a conical collecting cylinder, an oxygen carrier particle conveying pipe, an exchange component, and a vibration component. The bottom end of the external fixed sleeve is fixedly connected to the conical collecting cylinder, and the end of the conical collecting cylinder away from the external fixed sleeve is fixedly connected to the oxygen carrier particle conveying pipe.

[0018] In a preferred embodiment of the organic polluted soil thermal desorption system and treatment device provided by the present invention, the exchange component includes a top first fixed ring, a top second fixed ring, a bottom first fixed ring, a bottom second fixed ring, a top sliding ring, a bottom sliding ring, an outer mesh frame, an annular mesh plate, an inner mesh frame, and a top sealing cover. The top first fixed ring is fixedly connected to the middle of the outer fixed sleeve, the top second fixed ring is fixedly connected to the middle of the outer fixed sleeve, the bottom first fixed ring is fixedly connected to the middle of the outer fixed sleeve, the bottom second fixed ring is fixedly connected to the middle of the outer fixed sleeve, a top sliding ring is slidably connected to the middle of the top first fixed ring and the top second fixed ring, a bottom sliding ring is slidably connected to the middle of the bottom first fixed ring and the bottom second fixed ring, an outer mesh frame is fixedly connected to the middle of the top sliding ring and the bottom sliding ring, an annular mesh plate is fixedly connected to the middle of the outer mesh frame, an inner mesh frame is fixedly connected to the middle of the annular mesh plate, and a top sealing cover is fixedly connected to the top of the inner mesh frame.

[0019] In a preferred embodiment of the organic polluted soil thermal desorption system and treatment device provided by the present invention, the vibration assembly includes a geared motor, a drive shaft, a cam, a top return spring, and a bottom return spring. The geared motor is fixedly connected to the surface of the outer fixed sleeve, and the output end of the geared motor is drivenly connected to the drive shaft. The drive shaft is rotatably connected to the middle of the outer fixed sleeve. The cam is fixedly connected to the surface of the drive shaft and is in close contact with the top surface of the top sealing cover. A top return spring is provided in the middle of the top first fixed ring and the top second fixed ring, and the two ends of the top return spring are fixedly connected to the top second fixed ring and the top sliding ring, respectively. A bottom return spring is provided in the middle of the bottom first fixed ring and the bottom second fixed ring, and the two ends of the bottom return spring are fixedly connected to the bottom second fixed ring and the bottom sliding ring, respectively.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The organic contaminated soil thermal desorption system and treatment device provided by the present invention uses a solid heat source to directly heat the organic contaminated soil. On the one hand, it improves the heating effect, and on the other hand, it can obtain a higher concentration of volatile and semi-volatile organic compounds. It avoids the dilution of organic gases caused by conventional gas combustion heating and effectively reduces the treatment cost per unit of soil.

[0022] The organic polluted soil thermal desorption system and treatment device provided by the present invention uses chemical loop combustion technology to treat organic compounds in organic polluted soil. It replaces the free oxygen in the conventional air with lattice oxygen in the oxygen carrier, effectively preventing the generation of dioxins by direct combustion and effectively reducing the cost of subsequent flue gas treatment.

[0023] The organic polluted soil thermal desorption system and treatment device provided by the present invention, by setting up a moving bed reactor, the spiral arrangement of the annular mesh plate can increase the travel of the oxygen carrier particles inside the external fixed sleeve, thereby increasing the contact time between the oxygen carrier particles and volatile organic compounds, and thus increasing the chemical combustion time of volatile organic compounds.

[0024] The organic polluted soil thermal desorption system and treatment device provided by the present invention, by setting a vibration component in the moving bed reactor, can prevent the oxygen carrier particles from getting stuck in the middle of the mesh by pushing the external mesh frame, the annular mesh plate and the first gas outlet up and down through the cam due to the small particle size of the oxygen carrier particles, thereby increasing the circulation efficiency of the oxygen carrier particles. Attached Figure Description

[0025] To more clearly illustrate the solutions in this invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 A schematic diagram of the overall process of the thermal desorption system for organic polluted soil provided by the present invention;

[0027] Figure 2 A schematic diagram of the overall structure of the moving bed reactor in the organic polluted soil thermal desorption treatment device provided by the present invention.

[0028] Figure 3 A schematic diagram of the front plan of the moving bed reactor in the thermal desorption treatment device for organic polluted soil provided by the present invention.

[0029] Figure 4 A schematic diagram of the internal structure of the moving bed reactor in the thermal desorption treatment device for organic polluted soil provided by the present invention.

[0030] Figure 5 This is a schematic diagram of the internal structure of the external fixed sleeve in the moving bed reactor of the organic polluted soil thermal desorption treatment device provided by the present invention.

[0031] Figure 6 A schematic diagram of the exchange component in the moving bed reactor of the organic polluted soil thermal desorption treatment device provided by the present invention;

[0032] Figure 7 This is a schematic diagram of the vibration component in the moving bed reactor of the organic polluted soil thermal desorption treatment device provided by the present invention.

[0033] The markings in the diagram are explained as follows:

[0034] 1. First drum screen; 2. First conveyor belt; 3. First screw feeder; 4. First rotary kiln; 41. First gas outlet; 5. Second rotary kiln; 51. Second gas outlet; 6. Second drum screen; 7. Second conveyor belt; 8. Second screw feeder; 9. Elevator pipe; 10. Cyclone separator; 101. First inlet; 102. Third gas outlet; 11. Moving bed reactor; 111. Fourth gas outlet; 112. Fifth gas outlet; 12. Indirect heat exchanger; 121. First gas inlet; 122. Second gas inlet; 123. Sixth gas outlet; 13. Condenser; 14. First induced draft fan; 15. Second... 16. Exhaust fan; 17. First air blower; 18. Second air blower; 19. Natural gas heater; 20. Slag discharge valve; 21. Waste heat recovery device; 22. External fixing sleeve; 23. Conical collection cylinder; 24. Oxygen carrier particle conveying pipe; 25. Gear motor; 26. Drive shaft; 37. Cam; 38. Top first fixing ring; 39. Top second fixing ring; 30. Bottom first fixing ring; 31. Bottom second fixing ring; 32. Top sliding ring; 33. Bottom sliding ring; 34. Bottom return spring; 35. External mesh frame; 46. Annular mesh plate; 47. Internal mesh frame; 48. Top sealing cover. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0036] As described in the background section, there are currently two main types of thermal desorption systems for organically contaminated soil. One is the direct thermal desorption system, which uses hot flue gas (the heat usually comes from the combustion of natural gas) to directly heat the soil to a specified temperature. The advantage of this method is that the soil is in direct contact with the hot flue gas, resulting in high heat exchange efficiency. However, because the desorbed organic pollutants directly enter the flue gas, it significantly increases the volume and difficulty of treating the exhaust gas, thereby increasing treatment costs. The other type is the indirect thermal desorption system, which indirectly heats the soil through sleeves or hollow blades. Its advantage is that it reduces the volume and difficulty of treating the exhaust gas. However, because soil is a poor conductor of heat, its heat exchange efficiency is low. Furthermore, the hollow blades, in contact with the soil during rotation, experience severe wear and a high failure rate. In addition, in existing thermal desorption systems, the soil heating equipment is often a single unit, implementing the entire process of soil drying, heating, desorption of strongly volatile organic compounds (VOCs), and desorption of weakly VOCs within a single device. This makes it impossible to achieve graded control and optimization of each process to adapt to differences in soil characteristics.

[0037] To address this technical problem, the present invention provides a thermal desorption system and treatment device for organic polluted soil, which is applied to the thermal desorption of organic polluted soil.

[0038] For details, please refer to Figures 1-6 The organic polluted soil thermal desorption system and treatment device specifically includes a volatile organic compound thermal desorption mechanism, an oxygen carrier particle recovery mechanism, an organic gas attachment and gasification reaction mechanism, and a waste heat recovery mechanism. The volatile organic compound desorption mechanism is used to gasify and desorb volatile organic compounds in the soil. An oxygen carrier particle recovery mechanism is provided on one side of the volatile organic compound desorption mechanism for recovering oxygen carrier particles. An organic gas attachment and gasification reaction mechanism is provided on one side of the oxygen carrier particle recovery mechanism for performing a gasification reaction on volatile organic compounds. A waste heat recovery mechanism is provided at the upper end of the volatile organic compound desorption mechanism for recovering waste heat.

[0039] The volatile organic compound (VOC) removal mechanism includes a first drum screen 1, a first conveyor belt 2, a first screw feeder 3, a first rotary kiln 4, a second rotary kiln 5, a second drum screen 6, a slag discharge valve 19, and a gas conveying assembly. The first conveyor belt 2 is located at the bottom of the first drum screen 1. The first screw feeder 3 is located on the side of the first conveyor belt 2 away from the first drum screen 1. The first rotary kiln 4 is located at the bottom of the first screw feeder 3. The second rotary kiln 5 is located at the output end of the first rotary kiln 4. The second drum screen 6 is fixedly connected to the output end of the second rotary kiln 5. The slag discharge valve 19 is connected to the side of the second drum screen 6 away from the second rotary kiln 5 via a pipeline.

[0040] The organic contaminated soil thermal desorption system and treatment device provided by the present invention uses a solid heat source to directly heat the organic contaminated soil. On the one hand, it improves the heating effect, and on the other hand, it can obtain a higher concentration of volatile and semi-volatile organic compounds. It avoids the dilution of organic gases caused by conventional gas combustion heating and effectively reduces the treatment cost per unit of soil.

[0041] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0042] Example 1:

[0043] Please refer to Figure 1 A thermal desorption system and treatment device for organic polluted soil includes a volatile organic compound (VOC) thermal desorption mechanism, an oxygen carrier particle recovery mechanism, an organic gas attachment and gasification reaction mechanism, and a waste heat recovery mechanism. The VOC desorption mechanism is used to gasify and desorb VOCs in the soil. An oxygen carrier particle recovery mechanism is provided on one side of the VOC desorption mechanism for recovering oxygen carrier particles. An organic gas attachment and gasification reaction mechanism is provided on one side of the oxygen carrier particle recovery mechanism for performing a gasification reaction on VOCs. A waste heat recovery mechanism is provided at the upper end of the VOC desorption mechanism for recovering waste heat.

[0044] The volatile organic compound (VOC) removal mechanism includes a first drum screen 1, a first conveyor belt 2, a first screw feeder 3, a first rotary kiln 4, a second rotary kiln 5, a second drum screen 6, a slag discharge valve 19, and a gas conveying assembly. The first conveyor belt 2 is located at the bottom of the first drum screen 1. The first screw feeder 3 is located on the side of the first conveyor belt 2 away from the first drum screen 1. The first rotary kiln 4 is located at the bottom of the first screw feeder 3. The second rotary kiln 5 is located at the output end of the first rotary kiln 4. The second drum screen 6 is fixedly connected to the output end of the second rotary kiln 5. The slag discharge valve 19 is connected to the side of the second drum screen 6 away from the second rotary kiln 5 via a pipeline.

[0045] Specifically, the gas delivery assembly includes a first gas outlet 41, a second gas outlet 51, a partition wall heat exchanger 12, a first gas inlet 121, a second gas inlet 122, and a sixth gas outlet 123. The first gas outlet 41 is fixedly connected to the top surface of the first rotary kiln 4, and the second gas outlet 51 is fixedly connected to the top surface of the second rotary kiln 5. The partition wall heat exchanger 12 is provided at the upper end of the first rotary kiln 4 and the second rotary kiln 5. The first gas inlet 121 and the second gas inlet 122 are fixedly connected to the bottom surface of the partition wall heat exchanger 12. A condenser 13 is provided in the middle of the first rotary kiln 4 and the partition wall heat exchanger 12. The two ends of the condenser 13 are respectively connected to the middle of the first gas outlet 41 and the first gas inlet 121 through pipes. The second gas outlet 51 is connected to the middle of the second gas inlet 122 through a pipe. The sixth gas outlet 123 is fixedly connected to the top surface of the partition wall heat exchanger 12.

[0046] Specifically, the oxygen carrier particle recovery mechanism includes a second conveyor belt 7, a second screw feeder 8, a lifting pipe 9, and a cyclone separator 10. The second conveyor belt 7 is located at the bottom end of the second drum screen 6, and the second screw feeder 8 is located at the bottom end of the second conveyor belt 7. The lifting pipe 9 is fixedly connected to the end of the second screw feeder 8 away from the second conveyor belt 7, and the cyclone separator 10 is fixedly connected to the end of the lifting pipe 9 away from the second screw feeder 8.

[0047] Specifically, a second air blower 17 is provided in the middle of the riser pipe 9, a natural gas heater 18 is provided in the middle of the riser pipe 9, the second air blower 17 is provided at the upper end of the natural gas heater 18, a first inlet 101 is fixedly connected to the surface of the cyclone separator 10, a third gas outlet 102 is fixedly connected to the top surface of the cyclone separator 10, and the riser pipe 9 is fixedly connected to the cyclone separator 10 through the first inlet 101.

[0048] Specifically, the gasification reaction mechanism includes a moving bed reactor 11, a fourth gas outlet 111, and a fifth gas outlet 112. The moving bed reactor 11 is fixedly connected to the bottom end of the cyclone separator 10. The end of the moving bed reactor 11 away from the cyclone separator 10 is fixedly connected to the input end of the first rotary kiln 4. The fourth gas outlet 111 and the fifth gas outlet 112 are opened on the surface of the moving bed reactor 11.

[0049] Specifically, the sixth gas outlet 123 is connected to the moving bed reactor 11 and the fourth gas outlet 111 on the surface of the moving bed reactor 11 via a pipeline.

[0050] Specifically, the waste heat recovery mechanism includes a first induced draft fan 14, a second induced draft fan 15, a first air blower 16, and a waste heat recovery device 20. The first air blower 16 is installed on one side of the cyclone separator 10 and is connected to the moving bed reactor 11 via a pipeline. The first induced draft fan 14 is installed on one side of the moving bed reactor 11. The third gas outlet 102, the fourth gas outlet 111, and the fifth gas outlet 112 are connected to the input end of the first induced draft fan 14 via pipelines. The output end of the second induced draft fan 15 is connected to the input end of the partition heat exchanger 12 via a pipe. The output end of the partition heat exchanger 12 is connected to the waste heat recovery device 20 via a pipe. The output end of the waste heat recovery device 20 is connected to the output end of the first air blower 16 via a pipe. A three-way valve is provided in the middle of the partition heat exchanger 12 and the waste heat recovery device 20. The input end of the second induced draft fan 15 is connected to the partition heat exchanger 12 via a pipe and a three-way valve. The output end of the second induced draft fan 15 is connected to the riser pipe 9 via a pipe.

[0051] Through the above structural design, the organically contaminated soil first enters the first drum screen 1 to remove stones, branches, and other debris with a particle size greater than 10cm. Then, it passes through the first conveyor belt 2 and enters the first screw feeder 3, where it joins the high-temperature oxygen-carrying particles from the moving bed reactor 11 in the first rotary kiln 4 for heating. The heated organically contaminated soil in the first rotary kiln 4 undergoes a drying reaction, and the resulting water vapor, carrying some weakly volatile organic compounds, flows out from the first gas outlet 41 and enters the condenser 13 for condensation. The condensed water is then discharged and sent to a wastewater treatment plant for further treatment. After passing through the first rotary kiln 4, the soil enters the interior of the second rotary kiln 5 for further heating. The soil is then reheated inside the second rotary kiln 5, producing highly volatile organic compounds. The weakly volatile gas discharged from the first gas outlet 41 and the volatile gas flowing from the second gas outlet 51 merge in the indirect heat exchanger 12 through the first gas inlet 121 and the second gas inlet 122 respectively. They then enter the moving bed reactor 11 through the guide pipe in a cross-flow manner from the sixth gas outlet 123. Meanwhile, the soil heated by the first rotary kiln 4 and the second rotary kiln 5 passes through the second drum screen 6 and is discharged from the slag discharge valve 19. The second drum screen 6 removes the oxygen-carrying particles, which fall onto the surface of the second conveyor belt 7. After completion, the particles are conveyed by the second screw feeder 8 and the riser 9 through the first inlet 101 into the cyclone separator 10. Inside the riser 9, the oxygen-carrying particles are reheated by the natural gas heater 18. The oxygen-carrying particles are pressurized by the second air blower 17 and conveyed into the cyclone separator 10. After entering the cyclone separator 10, the hot gas is discharged from the third gas outlet 102 to the first induced draft fan 14, while the oxygen-carrying particles naturally fall into the moving bed reactor 11. At this time, volatile organic compounds and oxygen-carrying particles gather inside the moving bed reactor 11. The oxygen-carrying particles are ferric oxide. The volatile organic compounds react with the lattice oxygen in the oxygen-carrying particles through a gasification reaction, which can then cause the volatile organic compounds to undergo chemical combustion. After chemical combustion, the oxygen in the ferric oxide disappears and is converted into ferrous oxide. The gas after chemical combustion flows out from the fourth gas outlet 111 and gathers into the first induced draft fan 14. The oxygen-carrying particles reach the moving bed after passing through the moving bed reactor 11. At the bottom of reactor 11, after the oxygen carrier particles undergo chemical combustion, the crystalline oxygen on their surface reacts with carbon atoms in the volatile organic compounds to form carbon dioxide. The crystalline oxygen carried on the surface of the oxygen carrier particles is replaced by carbon atoms. At this time, the hot gas discharged from the third gas outlet 102 and the fourth gas outlet 111 is introduced into the partition heat exchanger 12 by the first induced draft fan 14 to exchange heat with the volatile organic compounds entering through the first gas inlet 121 and the second gas inlet 122. After passing through the partition heat exchanger 12, the hot gas enters the waste heat recovery device 20. Since a three-way valve is set between the partition heat exchanger 12 and the waste heat recovery device 20, part of the fuel gas is transported to the inside of the riser pipe 9 by the second induced draft fan 15, which can then heat the oxygen carrier particles for the next cycle.After the heat flow enters the waste heat recovery device 20, it is delivered to the first air blower 16. Some of the excess heat can be directly discharged from the waste heat recovery device 20. The second drum screen 6 supplies oxygen-mixed hot gas into the interior of the moving bed reactor 11. Since ferric oxide has been converted into ferrous oxide, the oxygen atoms supplied by the first air blower 16 react with the carbon atoms attached to the surface of the ferrous oxide to form carbon dioxide. At the same time, the crystalline oxygen on the surface of the ferrous oxide can be replenished and converted back into ferric oxide. The heat carried by the oxygen carrier particles themselves is transported by the first air blower 16 through the moving bed reactor 11 and finally... The gas is conveyed to the first induced draft fan 14 and collected inside. Along the moving bed reactor 11, a chemical looping gasification section and an oxygen carrier oxidation section are arranged sequentially from top to bottom. First, the oxygen carrier undergoes a chemical looping gasification reaction with the organic compounds obtained from thermal desorption in the organically contaminated soil, releasing lattice oxygen. Then, the oxygen carrier, having lost its lattice oxygen, enters the oxygen carrier oxidation section and undergoes an oxidation reaction with free oxygen in the air, replenishing the lattice oxygen. This system replaces the free oxygen in the air with lattice oxygen from the oxygen carrier, using chemical looping gasification to treat organic compounds in the organically contaminated soil. This effectively prevents the generation of dioxins from direct combustion and reduces subsequent flue gas treatment costs.

[0052] Example 2:

[0053] The thermal desorption system and treatment device for organic polluted soil provided in Example 1 have been further optimized, specifically, as follows: Figures 2-6 As shown, it includes a moving bed reactor 11;

[0054] The moving bed reactor 11 includes an external fixed sleeve 21, a conical collecting cylinder 26, an oxygen carrier particle conveying pipe 27, an exchange component, and a vibration component. The conical collecting cylinder 26 is fixedly connected to the bottom end of the external fixed sleeve 21, and the oxygen carrier particle conveying pipe 27 is fixedly connected to the end of the conical collecting cylinder 26 away from the external fixed sleeve 21.

[0055] Specifically, the switching assembly includes a top first fixing ring 31, a top second fixing ring 32, a bottom first fixing ring 33, a bottom second fixing ring 34, a top sliding ring 35, a bottom sliding ring 37, an outer mesh frame 39, an annular mesh plate 40, an inner mesh frame 43, and a top closing cover 42. The top first fixing ring 31 is fixedly connected to the middle of the outer fixing sleeve 21, the top second fixing ring 32 is fixedly connected to the middle of the outer fixing sleeve 21, and the bottom first fixing ring 33 is fixedly connected to the middle of the outer fixing sleeve 21. A bottom second fixing ring 34 is fixedly connected to the middle part of the structure. A top sliding ring 35 is slidably connected to the middle part of the top first fixing ring 31 and the top second fixing ring 32. A bottom sliding ring 37 is slidably connected to the middle part of the bottom first fixing ring 33 and the bottom second fixing ring 34. An outer mesh frame 39 is fixedly connected to the middle part of the top sliding ring 35 and the bottom sliding ring 37. An annular mesh plate 40 is fixedly connected to the middle part of the outer mesh frame 39. An inner mesh frame 43 is fixedly connected to the middle part of the annular mesh plate 40. A top closing cover 42 is fixedly connected to the top of the inner mesh frame 43.

[0056] Specifically, the vibration assembly includes a geared motor 28, a drive shaft 29, a cam 30, a top return spring 36, and a bottom return spring 38. The geared motor 28 is fixedly connected to the surface of the outer fixed sleeve 21. The output end of the geared motor 28 is drivenly connected to the drive shaft 29, which is rotatably connected to the middle of the outer fixed sleeve 21. The cam 30 is fixedly connected to the surface of the drive shaft 29 and is in close contact with the top surface of the top sealing cover 42. The top return spring 36 is provided in the middle of the top first fixed ring 31 and the top second fixed ring 32. The two ends of the top return spring 36 are fixedly connected to the top second fixed ring 32 and the top sliding ring 35, respectively. The bottom return spring 38 is provided in the middle of the bottom first fixed ring 33 and the bottom second fixed ring 34. The two ends of the bottom return spring 38 are fixedly connected to the bottom second fixed ring 34 and the bottom sliding ring 37, respectively.

[0057] Through the above structural design, when the volatile gas enters the outer fixed sleeve 21, the oxygen-carrying particles are simultaneously separated from the inside of the cyclone separator 10. After being separated from the cyclone separator 10, the oxygen-carrying particles fall onto the surface of the annular mesh plate 40. At this time, the volatile gas floats upward. When the oxygen-carrying particles come into contact with the volatile gas, the volatile gas undergoes chemical combustion. At the same time, the reduction motor 28 is activated. The reduction motor 28 drives the transmission shaft 29 to rotate. The transmission shaft 29 drives the cam 30 on the surface to rotate. The cam 30 can push the top sealing cover 42 to drive the inner mesh frame 43, the annular mesh plate 40, and the outer mesh frame 39 to descend. As the outer mesh frame 39 descends, it drives the top sliding ring. The top return spring 36 and bottom return spring 38 are pushed by the bottom sliding ring 35 and bottom sliding ring 37 to compress the cam 30 as it rotates. The highest and lowest points are constantly switching. When the highest point of the cam 30 contacts the top sealing cover 42, it pushes the top return spring 36 and bottom return spring 38 to compress the cam 30. When the lowest point of the cam 30 contacts the top sealing cover 42, the top return spring 36 and bottom return spring 38 push the top sliding ring 35 and bottom sliding ring 37 to rise. This repetition causes the annular mesh plate 40 to shake, which in turn causes the oxygen carrier particles on the surface of the annular mesh plate 40 to roll downwards. This increases the stroke of the oxygen carrier particles and allows them to be reused.

Claims

1. A thermal desorption system for organically polluted soil, characterized in that; It includes a volatile organic compound (VOC) thermal removal mechanism, an oxygen carrier particle recovery mechanism, an organic gas attachment and gasification reaction mechanism, and a waste heat recovery mechanism. The VOC removal mechanism is used to gasify and remove VOCs from the soil. An oxygen carrier particle recovery mechanism is provided on one side of the VOC removal mechanism for recovering oxygen carrier particles. An organic gas attachment and gasification reaction mechanism is provided on one side of the oxygen carrier particle recovery mechanism for performing a gasification reaction on VOCs. A waste heat recovery mechanism is provided at the upper end of the VOC removal mechanism for recovering waste heat. The volatile organic compound removal mechanism includes a first drum screen (1), a first conveyor belt (2), a first screw feeder (3), a first rotary kiln (4), a second rotary kiln (5), a second drum screen (6), a slag discharge valve (19), and a gas conveying assembly. The first conveyor belt (2) is provided at the bottom of the first drum screen (1). The first screw feeder (3) is provided on the side of the first conveyor belt (2) away from the first drum screen (1). The first rotary kiln (4) is provided at the bottom end of the first screw feeder (3). The second rotary kiln (5) is provided at the output end of the first rotary kiln (4). The second drum screen (6) is fixedly connected to the output end of the second rotary kiln (5). The slag discharge valve (19) is provided on the side of the second drum screen (6) away from the second rotary kiln (5) through a pipe. The oxygen carrier particle recovery mechanism includes a riser (9), a cyclone separator (10), and a natural gas heater (18). The organic gas attachment gasification reaction mechanism includes a moving bed reactor (11), and the bottom end of the cyclone separator (10) is fixedly connected to the moving bed reactor (11). The waste heat recovery mechanism includes a waste heat recovery device (20) and a first air blower (16); Organically contaminated soil and high-temperature oxygen-carrying particles from the moving bed reactor (11) enter the first rotary kiln (4) together; When the oxygen-carrying particles are inside the riser (9), they are reheated by the natural gas heater (18) and then transported to the cyclone separator (10) through the riser (9). The oxygen carrier particles fall naturally into the moving bed reactor (11) and react with the volatile organic compounds and lattice oxygen in the oxygen carrier through a gasification reaction. After the heat flow enters the waste heat recovery device (20), it is delivered to the first air blower (16). The oxygen atoms supplied by the first air blower (16) replenish the lattice oxygen of the oxygen carrier particles that have lost lattice oxygen.

2. The thermal desorption system for organically polluted soil according to claim 1, characterized in that, The gas delivery assembly includes a first gas outlet (41), a second gas outlet (51), a partition wall heat exchanger (12), a first gas inlet (121), a second gas inlet (122), and a sixth gas outlet (123). The top surface of the first rotary kiln (4) is fixedly connected to the first gas outlet (41), and the top surface of the second rotary kiln (5) is fixedly connected to the second gas outlet (51). The upper ends of the first rotary kiln (4) and the second rotary kiln (5) are provided with partition wall heat exchangers (12), and the bottom surface of the partition wall heat exchanger (12) is fixedly connected to the first gas outlet (41), the second gas outlet (51), the second gas inlet (51), the third gas outlet (51), the fourth gas outlet (51), the fifth gas outlet (51), the sixth ... A gas inlet (121) is provided. A second gas inlet (122) is fixedly connected to the bottom surface of the partition wall heat exchanger (12). A condenser (13) is provided in the middle of the first rotary kiln (4) and the partition wall heat exchanger (12). The two ends of the condenser (13) are respectively connected to the middle of the first gas outlet (41) and the first gas inlet (121) through pipes. The second gas outlet (51) is connected to the middle of the second gas inlet (122) through pipes. A sixth gas outlet (123) is fixedly connected to the top surface of the partition wall heat exchanger (12).

3. The thermal desorption system for organically polluted soil according to claim 2, characterized in that, The oxygen carrier particle recovery mechanism also includes a second conveyor belt (7) and a second screw feeder (8). The bottom end of the second drum screen (6) is provided with the second conveyor belt (7) and the bottom end of the second conveyor belt (7) is provided with the second screw feeder (8). The end of the second screw feeder (8) away from the second conveyor belt (7) is fixedly connected with a lifting pipe (9), and the end of the lifting pipe (9) away from the second screw feeder (8) is fixedly connected with a cyclone separator (10).

4. The thermal desorption system for organically contaminated soil according to claim 3, characterized in that, A second air blower (17) is provided in the middle of the riser pipe (9), and a natural gas heater (18) is provided in the middle of the riser pipe (9). The second air blower (17) is located at the upper end of the natural gas heater (18). A first inlet (101) is fixedly connected to the surface of the cyclone separator (10), and a third gas outlet (102) is fixedly connected to the top surface of the cyclone separator (10). The riser pipe (9) is fixedly connected to the cyclone separator (10) through the first inlet (101).

5. The thermal desorption system for organically contaminated soil according to claim 4, characterized in that, The gasification reaction mechanism also includes a fourth gas outlet (111) and a fifth gas outlet (112). The end of the moving bed reactor (11) away from the cyclone separator (10) is fixedly connected to the input end of the first rotary kiln (4). The surface of the moving bed reactor (11) is provided with a fourth gas outlet (111) and the surface of the moving bed reactor (11) is provided with a fifth gas outlet (112).

6. The thermal desorption system for organically contaminated soil according to claim 5, characterized in that, The sixth gas outlet (123) is connected to the moving bed reactor (11) and the fourth gas outlet (111) on the surface of the moving bed reactor (11) via a pipeline.

7. The thermal desorption system for organically contaminated soil according to claim 6, characterized in that, The waste heat recovery mechanism also includes a first induced draft fan (14) and a second induced draft fan (15). A first air blower (16) is provided on one side of the cyclone separator (10). The first air blower (16) is connected to the moving bed reactor (11) through a pipe. A first induced draft fan (14) is provided on one side of the moving bed reactor (11). The third gas outlet (102), the fourth gas outlet (111), and the fifth gas outlet (112) are connected to the input end of the first induced draft fan (14) through pipes. The output end of the first induced draft fan (14) is connected to the input end of the first induced draft fan (14) through a pipe. The pipe is connected to the input end of the partition wall heat exchanger (12). The output end of the partition wall heat exchanger (12) is connected to the waste heat recovery device (20) through a pipe. The output end of the waste heat recovery device (20) is connected to the output end of the first air blower (16) through a pipe. A three-way valve is provided in the middle of the partition wall heat exchanger (12) and the waste heat recovery device (20). The input end of the second induced draft fan (15) is connected to the partition wall heat exchanger (12) through a pipe and a three-way valve. The output end of the second induced draft fan (15) is connected to the riser pipe (9) through a pipe.

8. An organic polluted soil thermal desorption treatment device, applied to the organic polluted soil thermal desorption system according to any one of claims 1-7, characterized in that... ;Including moving bed reactor (11); The moving bed reactor (11) includes an external fixed sleeve (21), a conical collecting cylinder (26), an oxygen carrier particle conveying pipe (27), an exchange component, and a vibration component. The bottom end of the external fixed sleeve (21) is fixedly connected to the conical collecting cylinder (26), and the end of the conical collecting cylinder (26) away from the external fixed sleeve (21) is fixedly connected to the oxygen carrier particle conveying pipe (27).

9. The thermal desorption treatment device for organic polluted soil according to claim 8, characterized in that, The switching assembly includes a top first fixing ring (31), a top second fixing ring (32), a bottom first fixing ring (33), a bottom second fixing ring (34), a top sliding ring (35), a bottom sliding ring (37), an outer mesh frame (39), an annular + mesh plate (40), an inner mesh frame (43), and a top closing cover (42). The top first fixing ring (31) is fixedly connected to the middle of the outer fixing sleeve (21), the top second fixing ring (32) is fixedly connected to the middle of the outer fixing sleeve (21), and the bottom first fixing ring (33) is fixedly connected to the middle of the outer fixing sleeve (21). The bottom is fixedly connected to a second fixing ring (34). The top first fixing ring (31) and the top second fixing ring (32) are slidably connected to a top sliding ring (35). The bottom first fixing ring (33) and the bottom second fixing ring (34) are slidably connected to a bottom sliding ring (37). The top sliding ring (35) and the bottom sliding ring (37) are fixedly connected to an outer mesh frame (39). The outer mesh frame (39) is fixedly connected to an annular mesh plate (40). The annular mesh plate (40) is fixedly connected to an inner mesh frame (43). The top of the inner mesh frame (43) is fixedly connected to a top closing cover (42).

10. The thermal desorption treatment device for organic polluted soil according to claim 9, characterized in that, The vibration assembly includes a geared motor (28), a drive shaft (29), a cam (30), a top return spring (36), and a bottom return spring (38). The geared motor (28) is fixedly connected to the surface of the outer fixed sleeve (21). The output end of the geared motor (28) is driven by the drive shaft (29). The drive shaft (29) is rotatably connected to the middle of the outer fixed sleeve (21). The cam (30) is fixedly connected to the surface of the drive shaft (29). The cam (30) is connected to the top closing cover (…). 42) The top surface is closely attached. A top return spring (36) is provided in the middle of the top first fixing ring (31) and the top second fixing ring (32). The two ends of the top return spring (36) are fixedly connected to the top second fixing ring (32) and the top sliding ring (35) respectively. A bottom return spring (38) is provided in the middle of the bottom first fixing ring (33) and the bottom second fixing ring (34). The two ends of the bottom return spring (38) are fixedly connected to the bottom second fixing ring (34) and the bottom sliding ring (37) respectively.

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