Thermal desorption multi-layer barrel rotary kiln reactor for rapid restoration of site pollution

Abstract

The utility model discloses a thermal desorption multi-layer cylinder rotary kiln reactor for rapid restoration of site pollution, which comprises a rotary cylinder, a plurality of layers of inner cylinders are arranged in the rotary cylinder, the layers of inner cylinders are arranged in a mutually sleeved manner from inside to outside along the axial direction, the diameters of the layers of inner cylinders are gradually increased from inside to outside, and the diameters of the layers of inner cylinders are gradually increased from inside to outside. The interior of the rotary barrel is divided into a plurality of annular cavities by the multiple layers of inner barrels, sieve pores are formed in the side walls of the inner barrels, and the sieve pores in the inner barrel on the inner side are larger than the sieve pores in the inner barrel on the outer side; and a side wall cavity heat source input structure is arranged in the rotary cylinder and forms multi-point surrounding type heat source input corresponding to the annular cavity in the rotary cylinder. By arranging the multi-layer rotary cylinder structure and combining the pore size distribution of the screen, the polluted soil is subjected to heat transfer according to particle sizes in the rotary kiln, and compared with a conventional rotary kiln, under the condition that the cylinder length, the cylinder diameter and the cylinder inclination angle are the same, the rotary kiln can improve the complete reaction degree of materials or improve the treatment efficiency by about 50%.

Description

Technical Field

[0001] This utility model relates to the field of rotary reaction equipment technology, specifically to a multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites. Background Technology

[0002] Thermal desorption technology, with its significant advantages such as high efficiency and wide applicability, has gradually emerged in the field of soil remediation and has become one of the commonly used remediation methods. Its working principle is to use an external heat source to heat the contaminated soil, causing organic pollutants in the soil to volatilize or decompose under different temperature conditions, thereby separating them from the soil and achieving the goal of soil purification. Among many thermal desorption devices, the rotary kiln, as a core component, plays a crucial role in practical applications.

[0003] Traditional rotary kilns typically have a single-layer, elongated cylindrical structure. When used to treat organically contaminated soil, this structure reveals a series of significant drawbacks. From the perspective of soil adhesion, during the heating process, the organic components in the soil undergo softening and melting. These molten organic materials become highly viscous, easily adhering to surrounding soil particles and gradually forming large clumps over time. The presence of these clumps severely hinders the effective transfer of heat within the soil. Because the soil inside the clumps cannot fully absorb externally transferred heat, the thermal desorption reaction cannot proceed adequately, directly leading to a significant reduction in overall thermal desorption efficiency. More seriously, if the clumps become too large, they may block the material channels inside the kiln, forcing the equipment to stop operating and increasing maintenance costs and downtime losses.

[0004] In terms of particle processing, single-layer rotary kilns lack the ability to precisely differentiate and process materials of different particle sizes. In actual processing, large and small particles are mixed together before entering the kiln. Small particles, due to their larger surface area, have a greater and more thorough contact area with the high-temperature hot airflow within the rotary kiln, enabling them to quickly absorb heat and allowing the thermal desorption reaction to proceed rapidly. Conversely, the internal heat transfer process of large particles is relatively slow, requiring a longer time for heat to diffuse evenly into the particle's interior. This causes the thermal desorption reaction of large particles to lag behind that of small particles. This leads to the following dilemma in actual production: either large particles are discharged from the kiln before fully reacting, resulting in unsatisfactory soil remediation; or, to ensure sufficient reaction of large particles, the residence time of all materials within the kiln must be extended, which in turn leads to over-reaction of small particles. Over-reaction not only results in unnecessary energy consumption but also adversely affects the structure and properties of the small particles themselves, reducing their reaction efficiency and significantly increasing the overall cost of soil remediation.

[0005] In view of the above, it is necessary to propose a thermal desorption multi-layer rotary kiln reactor for rapid site remediation to solve the above problems. Utility Model Content

[0006] The purpose of this invention is to overcome the defects in the existing technology and provide a multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution.

[0007] To achieve the above objectives, the technical solution of this utility model is as follows:

[0008] A multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites includes a rotary cylinder, which is arranged between a kiln head hood and a kiln tail hood in a relatively rotating manner. Inside the rotary cylinder, there are multiple inner cylinders, which are arranged in an axial manner from the inside to the outside, with the diameter of the inner cylinders gradually increasing from the inside to the outside. The inner cylinders divide the interior of the rotary cylinder into multiple annular chambers. The side walls of the inner cylinders are provided with sieve holes, and the sieve holes on the inner inner cylinders are larger than those on the outer inner cylinders.

[0009] The kiln tail hood and kiln head hood are equipped with gas inlets and gas outlets according to the preset airflow direction. The rotary cylinder is provided with a side wall chamber heat source input structure, which forms a multi-point surrounding heat source input in the corresponding annular chamber in the rotary cylinder, so that the heat source acts directly and evenly on the materials between each layer.

[0010] Furthermore, the multi-layer inner cylinder includes a first inner cylinder and a second inner cylinder. The first inner cylinder is fixed inside the rotary cylinder by a first bracket, and the second inner cylinder is fixed inside the first inner cylinder by a second bracket. A first screen is formed on the surface of the first inner cylinder, and a second screen is formed on the surface of the second inner cylinder. The screen openings of the first screen are larger than those of the second screen.

[0011] The kiln head cover is equipped with a material inlet, which is connected to one end of the second inner cylinder, and the other end of the second inner cylinder is the discharge end.

[0012] Furthermore, the multi-layered inner cylinder is designed with each layer having a progressively larger diameter from the inside out, and the ratio of the outer cylinder diameter to the inner cylinder diameter is determined according to the Fibonacci sequence; each term equals the sum of the previous two terms. This sequence allows the cylinder diameter to exhibit a regular increasing trend. In soil thermal desorption treatment, this design matches the particle size distribution of the material, enabling better stratified treatment of materials with different particle sizes. The smaller diameter inner cylinder can initially treat small particles, while the gradually increasing cylinder diameter can accommodate and process larger particles, allowing materials of different sizes to undergo thermal desorption in their respective suitable spaces, thus improving treatment efficiency.

[0013] Furthermore, the sieve apertures on the sidewall of the inner cylinder are matched with the particle distribution of the material, and the aperture of the sieve apertures is 1-1.05 times the designed diameter of the material in the corresponding material layer;

[0014] The central axis of the rotating cylinder forms an angle with the horizontal plane, which is 0°-3°.

[0015] Furthermore, the sidewall chamber heat source input structure includes a spirally coiled air pipe arranged around the surface of the inner cylinder, and the sidewall of the spirally coiled air pipe is provided with an air jet port.

[0016] Furthermore, an anti-clogging structure is provided at the corresponding air nozzle location. The anti-clogging structure includes a comb-shaped enclosure. The air jet direction of the air nozzle is arranged radially. A shield is provided at intervals in the direction directly opposite the air nozzle. The shield is fixed to the surrounding comb-shaped enclosure.

[0017] Furthermore, the spiral-coiled air pipe is coiled on the inner surface of the inner cylinder, and the spiral-coiled air pipe protrudes from the surface of the inner cylinder, forming a spiral conveying blade on the inner cylinder. The spiral conveying blade formed by the spiral-coiled air pipe has an air jet port on the side away from the material inlet. The air jet port includes a conical protrusion and a conical recess. The tip of the conical protrusion points to the axis, and the tip of the conical recess points away from the axis. The bottom surfaces of the conical protrusion and the conical recess form a directional air jet opening, so that the airflow from the air jet opening is directed towards the inner wall surface of the inner cylinder. The bottom surface of the conical recess extends towards the tip of the conical protrusion, and similarly, the bottom surface of the conical protrusion extends towards the tip of the conical recess, so that the part extending from the bottom surface of the conical protrusion forms an anti-blocking and shielding edge for the air jet opening.

[0018] Furthermore, it also includes a crushing device, which includes a central rotating shaft that passes through the axis of the rotating cylinder. The central rotating shaft is provided with an inner crushing blade, and the inner wall surface of the inner cylinder is provided with an outer crushing blade, so that the inner crushing blade and the outer crushing blade rotate in opposite directions to crush the material.

[0019] Furthermore, the central rotating shaft is rotatably disposed between the kiln head hood and the kiln tail hood, and a shaft drive unit for driving the central shaft to rotate is provided at either end.

[0020] The advantages and beneficial effects of this utility model are as follows:

[0021] 1. The rotary kiln reactor with a multi-layered cylindrical structure for rapid remediation of complex site pollution, as described in this utility model, achieves particle-size heat transfer of polluted soil inside the rotary kiln by setting up a multi-layered rotary cylinder structure and combining it with the distribution of screen apertures. Compared with conventional rotary kilns, under the same cylinder length, cylinder diameter, and cylinder inclination angle, the solution described in this patent can improve the degree of complete material reaction or increase the processing efficiency by about 50%.

[0022] 2. The rotary kiln reactor with a multi-layered thermal desorption structure for rapid remediation of complex site pollution described in this utility model classifies contaminated soil according to different sizes, realizes the separation of contaminated soil with different particle sizes, and solves the compaction behavior of contaminated soil with different particle sizes and moisture contents inside the kiln body. Attached Figure Description

[0023] Figure 1 This is one of the schematic diagrams of the longitudinal section structure of the multi-layer cylindrical rotary kiln reactor in this utility model;

[0024] Figure 2 This is a perspective view of the multi-layered cylindrical body in this utility model;

[0025] Figure 3 This is one of the longitudinal cross-sectional schematic diagrams of the multi-layer cylinder in this utility model;

[0026] Figure 4 This is the second longitudinal cross-sectional schematic diagram of the multi-layer cylinder in this utility model;

[0027] Figure 5 This is a schematic diagram of the spiral-wound air pipe installed inside the inner cylinder in this utility model;

[0028] Figure 6 This is a schematic diagram of the spiral-wound air pipe installed on the outside of the inner cylinder in this utility model;

[0029] Figure 7 This is one of the schematic diagrams of the spiral conveying blade type spiral coiled air pipe in this utility model;

[0030] Figure 8 This is a schematic diagram of an air jet on a spiral conveyor blade in this utility model;

[0031] Figure 9 This is a schematic diagram of the crushing device in this utility model;

[0032] In the diagram: 1. Rotary cylinder; 2. Kiln head hood; 3. Kiln tail hood; 4. Inner cylinder; 5. Annular chamber; 6. Screen hole; 7. Gas inlet; 8. Gas outlet; 9. First inner cylinder; 10. Second inner cylinder; 11. First support; 12. Second support; 13. First screen; 14. Second screen; 15. Material inlet; 16. Discharge end; 17. Angle; 18. Spiral coiled gas pipe; 19. Air jet nozzle; 20. Comb-shaped enclosure; 21. Baffle plate; 22. Spiral conveyor blade; 23. Conical protrusion; 24. Conical recess; 25. Air jet opening; 26. Baffle edge; 27. Central rotating shaft; 28. Inner crusher; 29. ​​Outer crusher; 30. Shaft drive unit. Detailed Implementation

[0033] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0034] Example 1:

[0035] A multi-layer cylindrical rotary kiln reactor for rapid remediation of site contamination using thermal desorption, such as Figure 1-4 As shown, it includes a rotary cylinder 1, which is arranged between the kiln head hood 2 and the kiln tail hood 3 in a relatively rotating manner. Inside the rotary cylinder 1, there are multiple inner cylinders 4. Each inner cylinder 4 is arranged in a nested manner from the inside to the outside along the axial direction. The diameter of the multiple inner cylinders 4 gradually increases from the inside to the outside. The multiple inner cylinders 4 divide the interior of the rotary cylinder 1 into multiple annular chambers 5. The side walls of the inner cylinders 4 are provided with sieve holes 6, and the sieve holes 6 on the inner inner cylinders 4 are larger than the sieve holes 6 on the outer inner cylinders 4.

[0036] Specifically, the rotary kiln reactor, as a key piece of equipment for site remediation, is innovatively designed based on the traditional rotary kiln. The main body of the reactor, the rotary cylinder 1, is mounted between the kiln head hood 2 and the kiln tail hood 3 in a relatively rotating manner. Inside, multiple layers of inner cylinders 4 are nested together axially from the inside to the outside, arranged coaxially, dividing the interior of the rotary cylinder 1 into multiple annular chambers 5. Taking a typical structure including a first inner cylinder 9 and a second inner cylinder 10 as an example, the first inner cylinder 9 is fixed inside the rotary cylinder 1 by a first support 11, and the second inner cylinder 10 is installed inside the first inner cylinder 9 by a second support 12. Each inner cylinder has sieve holes 6 on its side wall, and the sieve holes 6 on the inner cylinder are larger than those on the outer cylinder. For example, the sieve holes 6 of the first screen 13 on the surface of the first inner cylinder 9 are larger than the sieve holes 6 of the second screen 14 on the surface of the second inner cylinder 10.

[0037] The reactor operates on the principle of synergistic material stratification and thermal desorption. Contaminated soil enters the second inner cylinder 10 through the material inlet 15 of the kiln head hood 2. As the rotating cylinder 1 rotates, small particles, limited by the size of the screen openings 6 of the second screen 14, pass through the screen openings 6 first and fall into the annular chamber 5 between the first inner cylinder 9 and the second inner cylinder 10. Larger particles remain in the second inner cylinder 10 for further processing. Similarly, some medium-sized particles pass through the first screen 13 and enter the annular chamber 5 between the rotating cylinder 1 and the first inner cylinder 9. In this way, materials of different particle sizes undergo thermal desorption treatment within their respective suitable spaces, avoiding the drawbacks of large particles not fully reacting and being discharged, and small particles over-reacting. During thermal desorption, a counter-current (or co-current) design is adopted, where the hot airflow flows in the opposite (or same) direction to the material. As it passes through each annular chamber 5, it fully contacts the material, transferring heat to it and promoting the volatilization and decomposition of organic pollutants. Furthermore, due to the differences in particle size among the layers, the heat transfer efficiency is optimized.

[0038] From a structural installation perspective, the two ends of the rotary cylinder 1 are respectively fitted with the kiln head hood 2 and the kiln tail hood 3. Stable support is achieved through the cooperation of two or more annular rolling rings fitted on the rotary cylinder 1 and the support roller device. The drive device drives the rotary cylinder 1 to rotate slowly around the central axis at a speed of 0.4-10 r / min via gear or chain transmission. During operation, the contaminated soil enters the second inner cylinder 10 through the material inlet 15 and completes stratification during the rotation of the cylinder. The hot airflow follows the counter-current (or co-current) path to contact the material and complete thermal desorption. The treated material is discharged from the material outlet of the kiln tail hood 3, and the hot airflow containing pollutants is discharged from the gas outlet 8 of the kiln head hood 2.

[0039] This design offers significant advantages. Precise layering within a multi-layered inner cylinder greatly improves processing efficiency, ensuring that materials of different particle sizes can react fully. Layered processing allows for more uniform contact between the hot airflow and the material, optimizing the heat transfer process and reducing energy consumption. Furthermore, the ratio of the outer cylinder diameter to the inner cylinder diameter and the size of the sieve openings can be flexibly adjusted according to the particle size distribution of the material, adapting to various contaminated soil treatment needs.

[0040] The following is a specific example. Assuming the diameter of the second inner cylinder 10 is 1 meter, and according to the Fibonacci sequence, the diameter of the first inner cylinder 9 is set to 2 meters, the diameter of the rotating cylinder 1 is 3 meters, and the length of the cylinder is 10 meters. Regarding the size of the sieve aperture 6, if the maximum particle size of the material layer corresponding to the second inner cylinder 10 is 5 mm, the diameter of the sieve aperture 6 is set to 5-5.25 mm; if the maximum particle size of the material layer corresponding to the first inner cylinder 9 is 15 mm, the diameter of the sieve aperture 6 is set to 15-15.75 mm. In the operating parameters, the rotational speed of the rotating cylinder 1 is selected between 0.4-10 r / min according to the material characteristics. For example, 0.4-2 r / min can be selected for highly viscous soil, and 5-10 r / min for highly fluid soil. The angle 17 between the central axis of the rotating cylinder 1 and the horizontal plane is controlled between 0° and 3° to allow the material to move towards the kiln tail under gravity. The hot airflow temperature is set between 200-600℃ according to the pollutant thermal desorption requirements, and the flow rate is determined based on the material throughput and heat transfer requirements to ensure efficient thermal desorption.

[0041] Example 2:

[0042] This embodiment is an improvement on Embodiment 1, such as... Figure 5-8 As shown, specifically, a heat source input structure is introduced into the sidewall chambers to improve thermal desorption efficiency and uniformity. This structure breaks the traditional heat source input mode, constructing a multi-point surrounding heat source input system corresponding to each annular chamber 5 within the rotating cylinder 1, ensuring that the heat source can act directly and uniformly on each layer of material, significantly optimizing the heat transfer process.

[0043] The heat source input structure of the side-wall chamber is based on a spirally coiled air pipe 18 that surrounds the surface of the inner cylinder 4. The spirally coiled air pipe 18 is arranged in a spiral shape and closely fits the surface of the inner cylinder 4. The air jets 19 evenly distributed on its side wall become the key nodes for heat source output. The spirally coiled air pipe 18 is hollow inside, with one end connected to the gas inlet 7 and the other end being a blind end. In actual use, the spirally coiled air pipe 18 rotates with the rotating cylinder, and one end is connected to the air inlet, so a rotating joint can be set. Moreover, the rotating joint does not require a strong sealing level, so the rotating connection can be easily achieved. Furthermore, by setting the air jets 19 on the surface of the spirally coiled air pipe 18 as the outlet of the heat source airflow, and by evenly distributing the outlets on the inner cylinder 4, the purpose of uniformly distributing the heat source can be achieved. The existing design only allows the heat to enter from one end of the rotating cylinder 1. It can be imagined that if a large amount of soil enters the cylinder, it will inevitably compress the cross-sectional area of ​​the gas flow, thus making the airflow obstructed, and the soil accumulation area cannot be effectively heated. This embodiment effectively solves the problem.

[0044] Furthermore, to address the problem of traditional jet nozzles 19 being easily clogged by fine soil particles, an innovative composite anti-clogging structure was designed. As one embodiment, the spirally coiled air pipe 18 can be formed inside the inner cylinder, such as... Figure 5As shown, the jet nozzle extends from the surface of the inner cylinder. The comb-shaped enclosure 20 surrounds the jet nozzle 19 to form a protective barrier. The jet nozzle 19 is arranged radially, and baffle plates 21 are arranged at intervals in the direction directly opposite it. Several uprights are set around the jet nozzle at certain intervals to form a comb-shaped structure, and baffle plates are fixed on the top of the uprights. The baffle plates 21 are firmly connected to the comb-shaped enclosure 20, effectively preventing materials from directly impacting the jet nozzle 19. The baffle plates 21 can block the front of the jet nozzle 19 to prevent soil from directly entering. By setting the interval distance, the gas can collide with the baffle plates 21 and then be sprayed out in all directions. The comb-shaped enclosure around the perimeter can intercept soil and support a certain space on the jet nozzle 19, allowing the airflow to flow out smoothly. In addition, the protruding enclosure can also exert a certain stirring effect on the soil to prevent soil clumping.

[0045] As another embodiment, such as Figure 6 The image shows a spiral coiled air pipe 18 with an air jet on the outer surface of the inner cylinder. Of course, the spiral coiled air pipe 18 can also be a spiral coiled air pipe 18 with a circular or square tube cross-section.

[0046] As another embodiment, such as Figure 7 , 8 As shown, the spiral coiled air pipe 18 is further optimized into a spiral conveying blade 22 protruding from the surface of the inner cylinder 4. At this time, it is coiled on the inner surface of the inner cylinder. The spiral conveying blade 22 is hollow inside to form an air pipe. A special air nozzle 19 is opened on the side away from the material inlet 15. The air nozzle 19 is composed of a conical protrusion 23 and a conical recess 24. The bottom surfaces of the two are opposite to each other to form an opening with a clear direction. The pointed tip of the conical protrusion 23 points towards the axis, while the pointed tip of the conical recess 24 faces away from the axis. After the airflow exits through this opening, it is precisely directed towards the inner wall surface of the inner cylinder 4, using the impact force of the airflow to continuously sweep the inner wall and prevent material adhesion. Simultaneously, the bottom surfaces of the conical protrusion 23 and the conical recess 24 extend to form an anti-clogging barrier 26, physically blocking the path of soil particles into the jet nozzle 19, achieving a dual anti-clogging effect. Specifically, since soil tends to fall and move from the center to the outside during feeding and rolling, setting the pointed tip of the conical protrusion 23 towards the axis creates a similar effect to that of a spray nozzle. The air opening 25 is designed to act as a protective shield, and for soil guidance, the air opening 25 is directional, meaning the ejected gas is blown towards the screen side, which helps to blow fine soil particles out of the screen and into the outer annular chamber 5, thereby accelerating the separation efficiency of soil particles. The conical recess 24 that is recessed inward can increase the size of the air opening 25. Furthermore, since it is designed as a spiral conveying blade 22, it also has the ability to transport soil axially. The direction of rotation of the rotating cylinder 1 can be adjusted to control the flow direction of the soil in the cylinder, thereby improving the axial distribution effect of the soil.

[0047] In actual implementation, the installation of the spiral coiled air pipe 18 must closely fit the contour of the inner cylinder 4 to ensure a uniform spiral shape. Taking a reactor containing three cylinders (second inner cylinder 10, first inner cylinder 9, and rotating cylinder 1) as an example, when installing the spiral coiled air pipe 18 on the inner surface of the second inner cylinder 10, the number of spiral turns and the pitch must be accurately calculated based on the cylinder diameter and length. Assuming the second inner cylinder 10 has a diameter of 1 meter and a length of 10 meters, the spiral coiled air pipe 18 can be set to coil 1.5 times per meter, with a pitch of approximately 667 mm, to ensure that the heat source evenly covers the material. In the anti-clogging structure, the comb-shaped baffle 20 is made of high-temperature resistant alloy material, and the spacing between the comb teeth is set to 15-20 mm, which can effectively block large particles of material without affecting the smooth airflow. The distance between the baffle plate 21 and the jet nozzle 19 is controlled at 30-50 mm to ensure that the airflow forms an effective buffer before impacting the material. In the air pipe design of the spiral conveying blade 22, the height of the conical protrusion 23 and the conical recess 24 is set to 15-20mm, and the bottom diameter is 25-35mm. The angle of the jet opening 25 formed by the combination of the two is controlled at 30°-45°, so that the airflow blows towards the inner wall of the inner cylinder 4 at the optimal angle.

[0048] The application of this side-wall chamber heat source input structure brings multiple significant advantages to the rotary kiln reactor. In terms of heat transfer efficiency, the multi-point surrounding heat source input mode allows each layer of material to receive heat uniformly and comprehensively. Compared to traditional heat source input methods, heat transfer efficiency is improved by more than 30%, effectively shortening the thermal desorption treatment time. The innovative anti-clogging structure design greatly reduces the probability of clogging at the jet nozzle 19. Simulation experiments have verified that when treating contaminated soil containing up to 30% fine particles, the clogging frequency of the jet nozzle 19 has decreased from 5-8 times per hour in the traditional design to less than once every 10 hours, significantly improving the equipment's continuous and stable operation capability. The spiral conveyor blade 22-shaped air pipe design achieves heat source injection while conveying materials, reducing the need for additional conveying components, simplifying the equipment structure, and lowering manufacturing costs and maintenance difficulty. Furthermore, through precise control of the jet nozzle 19 angle and airflow direction, local overheating or overcooling can be effectively avoided, keeping the material temperature fluctuation range within ±3℃, further improving the uniformity of thermal desorption treatment and the pollutant removal effect.

[0049] Example 3:

[0050] As an improvement, this embodiment incorporates an integrated crushing device, effectively addressing the industry pain point of low thermal desorption efficiency for large materials. This device is centered on a central rotating shaft 27 that runs through the axis of the rotating cylinder 1. Figure 9 As shown, the inner crushing blade 28 on the central rotating shaft 27 and the outer crushing blade 29 on the inner wall of the inner cylinder form a counter-rotating shearing and crushing system, which completes particle size refinement in real time during material conveying, laying an efficient foundation for the subsequent thermal desorption process.

[0051] The crushing device utilizes the shearing and impact forces generated by relative motion to crush materials. The central rotating shaft 27 drives the inner crushing blades 28 to rotate, and its rotation speed can be controlled by the shaft drive unit 30. In addition, the shaft drive unit 30 is an optional configuration. If the shaft drive unit 30 is not provided, the central shaft is a fixed shaft, and the relative motion of the crushing blades is generated by the rotation of the rotating cylinder 1 itself, thereby crushing the soil.

[0052] Furthermore, the inner crushing blade 28 and the outer crushing blade 29 fixed to the inner wall of the inner cylinder form an interlaced crushing space. When large pieces of material enter this area, they are simultaneously blocked and cut by both the inner and outer crushing blades 28 and 29, and are torn and crushed under the dual forces. This reverse rotation design can produce a multi-dimensional crushing effect, not only tearing the material axially, but also generating shear force in the circumferential direction, ensuring that the particle size after crushing is more uniform, effectively increasing the contact area between the material and the heat source, and enhancing the thermal desorption efficiency.

[0053] In actual engineering implementation, the central rotating shaft 27 is made of high-strength alloy steel, and its diameter needs to be customized according to the specifications and throughput of the rotary kiln. Taking a rotary kiln with a throughput of 5 tons / hour as an example, the diameter of the central rotating shaft 27 can be set to 120-150mm, which can ensure sufficient torque transmission while avoiding the impact of excessive shaft diameter on the internal space layout. The central rotating shaft 27 is rotatably installed between the kiln head cover 2 and the kiln tail cover 3 through high-precision bearings. The bearings need to have high temperature resistance and high load characteristics to adapt to the complex working conditions inside the rotary kiln. The shaft drive unit 30 can use a drive scheme of variable frequency motor and reducer, and the speed can be flexibly adjusted according to the material characteristics. The inner crusher blade 28 adopts a detachable modular design with a blade length of 200-300mm and a blade thickness of 15-20mm. It is fixed to the central rotating shaft 27 with bolts for easy replacement after wear. The outer crusher blade 29 is directly welded to the inner wall of the inner cylinder. Its blade length is adapted to the inner crusher blade 28, and its blade angle is designed to be 45°-60° to optimize the shearing effect.

[0054] The application of this integrated crushing device has brought significant improvements to the rotary kiln reactor. In terms of processing efficiency, actual tests have shown that when treating contaminated soil containing 20%-30% particles larger than 50mm, the average particle size of the crushed material can be reduced to below 20mm, and the thermal desorption efficiency is increased by 25%-35%, effectively reducing secondary treatment costs caused by large material residues. Furthermore, the integrated design eliminates the need for additional crushing space, achieving functional upgrades without altering the overall dimensions of the rotary kiln, making it highly practical for site-constrained pollution remediation projects. Through a variable frequency speed control system, the crushing intensity can be adjusted in real time for materials with different hardness and moisture content. The equipment is applicable to a wide range of contaminated media, from cohesive soils to sandy soils, significantly enhancing the versatility and adaptability of the rotary kiln reactor.

[0055] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites, characterized in that, It includes a rotary cylinder, which is set between the kiln head hood and the kiln tail hood in a relatively rotating manner. Inside the rotary cylinder, there are multiple layers of inner cylinders. Each layer of inner cylinder is arranged in a nested manner from the inside to the outside along the axial direction. The diameter of the multiple layers of inner cylinders gradually increases from the inside to the outside. The multiple layers of inner cylinders divide the interior of the rotary cylinder into multiple annular chambers. The side walls of the inner cylinders are provided with sieve holes, and the sieve holes on the inner inner cylinders are larger than the sieve holes on the outer inner cylinders. The kiln tail hood and kiln head hood are equipped with gas inlets and gas outlets according to the preset airflow direction. The rotary cylinder is provided with a side wall chamber heat source input structure, which forms a multi-point surrounding heat source input in the corresponding annular chamber in the rotary cylinder, so that the heat source acts directly and evenly on the materials between each layer.

2. The multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites according to claim 1, characterized in that, The multi-layer inner cylinder includes a first inner cylinder and a second inner cylinder. The first inner cylinder is fixed inside the rotary cylinder by a first bracket, and the second inner cylinder is fixed inside the first inner cylinder by a second bracket. A first screen is formed on the surface of the first inner cylinder, and a second screen is formed on the surface of the second inner cylinder. The sieve holes of the first screen are larger than the sieve holes of the second screen. The kiln head cover is equipped with a material inlet, which is connected to one end of the second inner cylinder, and the other end of the second inner cylinder is the discharge end.

3. The multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites according to claim 1, characterized in that, The multi-layered inner cylinder is designed with each layer having a progressively larger diameter from the inside out, and the ratio of the outer cylinder diameter to the inner cylinder diameter is determined according to the Fibonacci sequence.

4. The multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites according to claim 1, characterized in that, The sieve apertures on the side wall of the inner cylinder are matched with the particle distribution of the material, and the aperture of the sieve apertures is 1-1.05 times the designed diameter of the material in the corresponding material layer; The central axis of the rotating cylinder forms an angle with the horizontal plane, which is 0°-3°.

5. The multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites according to claim 1, characterized in that, The sidewall chamber heat source input structure includes a spiral coiled air pipe arranged around the surface of the inner cylinder, and the sidewall of the spiral coiled air pipe is provided with an air jet port.

6. The multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites according to claim 5, characterized in that, A blockage prevention structure is provided at the corresponding air outlet. The blockage prevention structure includes a comb-shaped enclosure. The air outlet is arranged radially. A shield is provided at intervals in the direction directly opposite the air outlet. The shield is fixed to the surrounding comb-shaped enclosure.

7. The multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites according to claim 5, characterized in that, The spiral-coiled air pipe is coiled on the inner surface of the inner cylinder. The spiral-coiled air pipe protrudes from the surface of the inner cylinder, forming a spiral conveying blade on the inner cylinder. The spiral conveying blade formed by the spiral-coiled air pipe has an air jet port on the side away from the material inlet. The air jet port includes a conical protrusion and a conical recess. The tip of the conical protrusion points to the axis, and the tip of the conical recess points away from the axis. The bottom surfaces of the conical protrusion and the conical recess form a directional air jet opening, so that the airflow from the air jet opening is directed towards the inner wall surface of the inner cylinder. Furthermore, the bottom surface of the conical recess extends towards the tip of the conical protrusion, and similarly, the bottom surface of the conical protrusion extends towards the tip of the conical recess, so that the extended portion of the bottom surface of the conical protrusion forms a blocking edge for the air jet opening.

8. The multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites according to claim 1, characterized in that, It also includes a crushing device, which includes a central rotating shaft that passes through the axis of the rotating cylinder. The central rotating shaft is provided with an inner crushing blade, and the inner wall surface of the inner cylinder is provided with an outer crushing blade, so that the inner crushing blade and the outer crushing blade rotate in opposite directions to crush the material.

9. A multi-layer cylindrical rotary kiln reactor for rapid site remediation of contaminated sites, as described in claim 8, is characterized in that... The central rotating shaft is rotatably positioned between the kiln head hood and the kiln tail hood, and a shaft drive unit for driving the central shaft to rotate is provided at either end.

Images