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

Abstract

The invention 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 plurality of layers of inner cylinders are gradually increased from inside to outside, and the diameters of the plurality of 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] The present invention relates to the technical field of rotary reaction equipment, and particularly relates to a thermal desorption multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution. Background Art

[0002] In the current context of the rapid advancement of the global industrialization process, the problem of soil organic pollution has become increasingly prominent and has become a major hidden danger threatening ecological environment safety and human health. A large number of industrial production activities, such as petrochemical industry, pesticide manufacturing, waste incineration, etc., continuously release various organic pollutants into the soil environment, such as polycyclic aromatic hydrocarbons, organochlorine pesticides, petroleum hydrocarbons, etc. These organic pollutants continuously accumulate in the soil, not only damaging the physical and chemical properties of the soil, inhibiting the activity of microorganisms in the soil, affecting the normal growth and development of plants, but also endangering human health through the biological enrichment effect of the food chain. Thermal desorption technology has gradually emerged in the field of soil remediation and has become one of the commonly used remediation methods due to its significant advantages such as high efficiency and wide application range. Its working principle is to use an external heat source to heat the contaminated soil, causing the organic pollutants in the soil to volatilize or decompose under different temperature conditions, and then separating them from the soil to achieve the goal of soil purification. Among many thermal desorption devices, the rotary kiln, as the core component, plays a key role in practical applications. For traditional rotary kilns, their cylinders are mostly of a single-layer long cylindrical structure. When used to treat organically contaminated soil, this structure exposes a series of drawbacks that cannot be ignored. From the perspective of soil adhesion, during the heating process, the organic components in the soil will undergo physical changes such as softening and melting. These molten organic substances have greatly increased viscosity and are extremely easy to adhere to the surrounding soil particles. Over time, they gradually form larger soil masses. The existence of these soil masses greatly hinders the effective transfer of heat within the soil. Since the soil inside the soil masses is difficult to fully absorb the heat transmitted from the outside, the thermal desorption reaction cannot proceed fully, directly resulting in a significant reduction in the overall thermal desorption efficiency. More seriously, once the soil mass is too large, it may also block the material channel inside the kiln body, forcing the equipment to stop running, increasing the equipment maintenance cost and production stoppage losses.

[0003] In terms of the treatment of material particles, a single-layer rotary kiln lacks the ability to accurately distinguish and process materials of different particle sizes. During the actual treatment process, large-particle and small-particle materials are mixed and enter the kiln body. Due to their large specific surface area, small-particle materials have a larger contact area and more sufficient contact with the high-temperature hot gas flow in the rotary kiln, can quickly absorb heat, and the thermal desorption reaction can proceed rapidly. On the contrary, for large-particle materials, the internal heat transfer process is relatively slow, and it takes a long time for the heat to evenly diffuse into the interior of the particles, which makes the thermal desorption reaction of large-particle materials lag behind that of small-particle materials. As a result, in actual production, such a dilemma will occur: either the large-particle materials are discharged from the kiln body along with the overall conveying of the materials before they are completely reacted, resulting in the soil remediation effect not reaching the expected level; or in order to ensure the full reaction of the large-particle materials, it is necessary to extend the residence time of all materials in the kiln body, which will cause the small-particle materials to react excessively. Excessive reaction will not only cause unnecessary energy consumption, but also have an adverse impact on the structure and properties of the small-particle materials themselves, reduce their reaction efficiency, and significantly increase the comprehensive cost of soil remediation.

[0004] In view of the above, it is necessary to propose a thermal desorption multi-layer cylinder rotary kiln reactor for rapid remediation of site pollution to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects existing in the prior art and provide a thermal desorption multi-layer cylinder rotary kiln reactor for rapid remediation of site pollution.

[0006] To achieve the above purpose, the technical solution of the present invention is as follows: A thermal desorption multi-layer cylinder rotary kiln reactor for rapid remediation of site pollution includes a rotary cylinder body, which is arranged between a kiln head cover and a kiln tail cover in a relatively rotatable manner. Inside the rotary cylinder body, there are multiple inner cylinders, and each layer of inner cylinders is arranged in a nested manner along the axis from the inside to the outside. The diameters of the multiple inner cylinders gradually increase from the inside to the outside. The multiple inner cylinders divide the interior of the rotary cylinder body into multiple annular chambers. The side walls of the inner cylinders are provided with sieve holes, and the sieve holes on the inner side inner cylinder are larger than the sieve holes on the outer side inner cylinder; Gas inlets and gas outlets are provided on the kiln tail cover and the kiln head cover according to the preset gas flow direction. A side wall chamber heat source input structure is arranged inside the rotary cylinder body, which forms a multi-point surrounding heat source input corresponding to the annular chambers inside the rotary cylinder body, so that the heat source directly and evenly acts on the materials between the layers.

[0007] Further, the multi-layer inner cylinder body includes a first inner cylinder and a second inner cylinder. The first inner cylinder is fixedly arranged inside the rotary cylinder body through a first support, and the second inner cylinder is fixedly arranged inside the first inner cylinder through a second support; 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 holes of the first screen are larger than those of the second screen; A material inlet is provided on the kiln head hood, and the material inlet is communicated with one end of the second inner cylinder, and the other end of the second inner cylinder is the discharge end.

[0008] Further, the multi-layer inner cylinder body is designed with the diameter of each layer of cylinder body increasing layer by layer from the inside to the outside, and the ratio of the diameter of the outer cylinder body to the inner cylinder is determined according to the Fibonacci sequence; each term is equal to the sum of the previous two terms. Such a sequence can make the change of the cylinder body diameter show a regular increasing trend. In the soil thermal desorption treatment, this design matches the material particle distribution and can better achieve the layered treatment of materials with different particle sizes. The inner cylinder with a smaller diameter can first perform preliminary treatment on small particle materials. As the diameter of the cylinder body gradually increases, it can accommodate and process larger particle materials, enabling materials with different particle sizes to perform thermal desorption in their respective suitable spaces and improving the treatment efficiency.

[0009] Further, the aperture of the screen holes provided on the side wall of the inner cylinder body matches the material particle distribution, and the aperture of the screen holes is 1-1.05 times the designed material diameter of the corresponding material layer; An included angle is formed between the central axis of the rotary cylinder body and the horizontal plane, and the included angle is 0°-3°.

[0010] Further, the side wall chamber heat source input structure includes a spiral coiled gas pipe arranged around the surface of the inner cylinder body, and a jet port is provided on the side wall of the spiral coiled gas pipe.

[0011] Further, an anti-blocking structure is provided corresponding to the jet port. The anti-blocking structure includes a comb-shaped enclosure part. The jet direction of the jet port is arranged radially, and a baffle is arranged at an interval distance in the direct facing direction of the jet port. The baffle is fixed on the surrounding comb-shaped enclosure part.

[0012] Furthermore, the spirally coiled air pipe is coiled on the inner surface of the inner cylinder, and the spirally coiled air pipe is protruded from the surface of the inner cylinder to form a spiral conveying blade arranged on the inner cylinder. The spiral conveying blade formed by the spirally coiled air pipe is provided with an air jet on the side away from the material inlet, and the air jet includes a conical protrusion and a conical recessed portion, the tip of the conical protrusion points to the axis, and the tip of the conical recessed portion points away from the axis, and the bottom surfaces of the conical protrusion and the conical recessed portion relatively form a directional air jet opening; the airflow ejection direction of the air jet opening is directed to the inner wall surface of the inner cylinder; and the bottom surface side of the conical recessed portion extends toward the tip of the conical protrusion, and similarly, the bottom surface side of the conical protrusion extends toward the tip of the conical recessed portion, so that the portion extending from the bottom surface of the conical protrusion forms an anti-blocking shielding edge for the air jet opening.

[0013] Furthermore, it also includes a crushing device, which includes a central rotating shaft, which passes through the axis of the rotating cylinder, and an inner crushing knife is provided on the central rotating shaft, and an outer crushing knife is provided on the inner wall surface of the inner cylinder, so that the inner crushing knife and the outer crushing knife rotate in opposite directions to crush the material.

[0014] Furthermore, the central rotating shaft is rotatably arranged between the kiln head cover and the kiln tail cover, and a shaft driving part for driving the central shaft to rotate is provided at either end.

[0015] The advantages and beneficial effects of the present invention are: 1. The rotary kiln reactor with a multi-layer cylinder for rapid remediation of complex pollution on sites and thermal desorption described in the present invention realizes particle size-based heat transfer of contaminated soil inside the rotary kiln by setting a multi-layer rotary cylinder structure and combining the sieve aperture distribution. Compared with conventional rotary kilns, under the same cylinder length, cylinder diameter and cylinder inclination, the scheme described in this patent can improve the degree of complete reaction of materials or increase the treatment efficiency by about 50%.

[0016] 2. The rotary kiln reactor with a multi-layer cylinder for thermal desorption for rapid remediation of complex pollution on sites described in the present invention can classify the contaminated soil according to different sizes, separate the contaminated soils of different particle sizes from each other, and solve the problem of compaction of contaminated soils of different particle sizes and moisture contents inside the kiln body. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is one of the longitudinal cross-sectional structural schematic diagrams of the multi-layer cylindrical rotary kiln reactor in the present invention; Figure 2 is a three-dimensional diagram of a multi-layer cylinder in the present invention; Figure 3 It is one of the longitudinal cross-sectional schematic diagrams of the multi-layer cylinder in the present invention; Figure 4 This is the second longitudinal cross-sectional schematic diagram of the multi-layer cylinder in the present invention; Figure 5 It is a schematic diagram of the spiral coiled trachea arranged inside the inner cylinder in the present invention; Figure 6 It is a schematic diagram of the spiral coiled trachea arranged outside the inner cylinder in the present invention; Figure 7 It is one of the schematic diagrams of the spiral coiled trachea with spiral conveying blades in the present invention; Figure 8 It is a schematic diagram of a jet orifice on the spiral conveying blade in the present invention; Figure 9 It is a schematic diagram of the crushing device in the present invention; In the figure: 1, rotary cylinder; 2, kiln head hood; 3, kiln tail hood; 4, inner cylinder; 5, annular chamber; 6, sieve 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, included angle; 18, spiral coiled trachea; 19, jet orifice; 20, comb-shaped baffle part; 21, baffle plate; 22, spiral conveying blade; 23, conical convex part; 24, conical concave part; 25, jet opening; 26, shielding edge; 27, central rotating shaft; 28, inner side crushing knife; 29, outer side crushing knife; 30, shaft driving part. Specific Embodiments

[0018] The following combines the drawings and embodiments to further describe the specific embodiments of the present invention. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0019] Embodiment 1: A thermal desorption multi-layer cylinder rotary kiln reactor for rapid remediation of site pollution, as Figures 1-4 shown, includes a rotary cylinder 1, the rotary cylinder 1 is arranged between the kiln head hood 2 and the kiln tail hood 3 in a relatively rotatable manner, and multiple layers of inner cylinders 4 are arranged inside the rotary cylinder 1. The inner cylinders 4 of each layer are arranged in a nested manner along the axis from the inside to the outside. The diameters of the multiple layers of inner cylinders 4 gradually increase from the inside to the outside. The multiple layers of inner cylinders 4 divide the inside of the rotary cylinder 1 into multiple annular chambers 5. Sieve holes 6 are provided on the side walls of the inner cylinders 4, and the sieve holes 6 on the inner side inner cylinder 4 are larger than the sieve holes 6 on the outer side inner cylinder 4; Specifically, as a key device for site pollution remediation, the rotary kiln reactor is innovated on the basis of the traditional rotary kiln. The main body of the reactor, the rotary cylinder 1, is erected between the kiln head hood 2 and the kiln tail hood 3 in a relatively rotating manner. The internal multi-layer inner cylinders 4 are sleeved with each other from the inside to the outside along the axial direction and are arranged coaxially, dividing the inside of the rotary cylinder 1 into multiple annular chambers 5. Taking a typical structure including the first inner cylinder 9 and the second inner cylinder 10 as an example, the first inner cylinder 9 is fixed inside the rotary cylinder 1 through the first bracket 11, and the second inner cylinder 10 is installed inside the first inner cylinder 9 by means of the second bracket 12. Sieve holes 6 are provided on the side walls of each inner cylinder, and the sieve holes 6 of the inner side inner cylinder are larger than those of the outer side. 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.

[0020] The working principle of this reactor is based on the synergistic effect of material stratification and thermal desorption. The contaminated soil enters the second inner cylinder 10 from the material inlet 15 of the kiln head hood 2. As the rotary cylinder 1 rotates, due to the limitation of the sieve hole 6 size of the second screen 14, the small particle materials take the lead in passing through the sieve holes 6 and falling into the annular chamber 5 between the first inner cylinder 9 and the second inner cylinder 10, while the larger particle materials remain in the second inner cylinder 10 for further treatment. Similarly, some medium particle materials will pass through the first screen 13 and enter the annular chamber 5 between the rotary cylinder 1 and the first inner cylinder 9. In this way, materials of different particle sizes are subjected to thermal desorption treatment in their respective suitable spaces, avoiding the disadvantages of large particles being discharged without sufficient reaction and small particles being overreacted. During the thermal desorption process, a countercurrent (or co-current) design is adopted, and the hot gas flow flows reversely (or co-currently) with the material, fully contacting the material when passing through each annular chamber 5, transferring heat to the material, promoting the volatilization and decomposition of organic pollutants, and optimizing the heat transfer efficiency due to the particle size difference of each layer of materials.

[0021] From the perspective of structural installation, both ends of the rotary cylinder 1 are respectively sleeved with the kiln head hood 2 and the kiln tail hood 3, and are stably supported by means of two or more circular rolling rings sleeved on the rotary cylinder 1 and cooperating with the supporting wheel device. The driving device drives the rotary cylinder 1 to slowly rotate around the central axis at a speed of 0.4 - 10 r / min through gear or chain drive. During operation, the contaminated soil enters the second inner cylinder 10 from the material inlet 15, is stratified during the rotation of the cylinder, the hot gas flow contacts the material along the countercurrent (or co-current) path to complete thermal desorption, the treated material is discharged from the material outlet of the kiln tail hood 3, and the hot gas flow containing pollutants is discharged from the gas outlet 8 of the kiln head hood 2.

[0022] This design has significant advantages. Through precise stratification by multiple inner cylinders, the treatment efficiency is greatly improved, ensuring that materials of different particle sizes can fully react; the stratified treatment makes the contact between the hot gas flow and the material more uniform, optimizes the heat transfer process, and reduces energy consumption; and the relative diameter ratio of the outer cylinder to the inner cylinder and the size of the sieve holes 6 can be flexibly adjusted according to the particle distribution of the material to adapt to the treatment requirements of various contaminated soils.

[0023] Specific examples are given below. Assume that the diameter of the second inner cylinder 10 is 1 meter. According to the Fibonacci sequence, the diameter of the first inner cylinder 9 is set to 2 meters, the diameter of the rotary cylinder 1 is 3 meters, and the length of the cylinder is taken as 10 meters. In terms of the size of the sieve holes 6, if the maximum particle size of the material layer corresponding to the second inner cylinder 10 is 5 mm, the diameter of its sieve holes 6 is set to 5 - 5.25 mm; for the first inner cylinder 9, the maximum particle size of the material layer is 15 mm, and the diameter of the sieve holes 6 is set to 15 - 15.75 mm. Among the operating parameters, the rotation speed of the rotary cylinder 1 is selected between 0.4 - 10 r / min according to the material characteristics. For example, for soils with high viscosity, 0.4 - 2 r / min can be selected, and for soils with good fluidity, 5 - 10 r / min can be selected; the angle 17 between the central axis of the rotary cylinder 1 and the horizontal plane is controlled within 0° - 3° to enable the material to move towards the kiln tail under the action of gravity; the temperature of the hot gas flow is set at 200 - 600 °C according to the thermal desorption requirements of pollutants, and the flow rate is determined in combination with the material processing capacity and heat transfer requirements to ensure efficient thermal desorption.

[0024] Example Two: As an improvement to Example One, as Figures 5-8 shown, specifically, a sidewall chamber heat source input structure is introduced to improve the thermal desorption efficiency and uniformity. This structure breaks the traditional heat source input mode and constructs a multi-point surrounding heat source input system corresponding to each annular chamber 5 in the rotary cylinder 1, ensuring that the heat source can directly and evenly act on each layer of the material, significantly optimizing the heat transfer process.

[0025] The sidewall chamber heat source input structure takes the spiral coiled gas pipe 18 surrounding the surface of the inner cylinder 4 as the core component. The spiral coiled gas pipe 18 is closely attached to the surface of the inner cylinder 4 and is arranged in a spiral shape. The jet holes 19 evenly distributed on its sidewall become the key nodes for heat source output. The inside of the spiral coiled gas pipe 18 is hollow. One end of it is connected to the gas inlet 7, and the other end is a blind end. In actual use, the spiral coiled gas pipe 18 rotates with the rotary cylinder, and one end of it is connected to the air inlet, so a rotating joint can be set, and this rotating joint does not require a high sealing level, so the rotating connection can be conveniently realized; further, by using the jet holes 19 provided on the surface of the spiral coiled gas pipe 18 as the jet outlets for the heat source gas flow and evenly arranging the jet outlets on the inner cylinder 4, the purpose of evenly distributing the heat source can be achieved. In the existing design, the heat source only enters from one end of the rotary cylinder 1. It can be imagined that if a large amount of soil enters the cylinder, the cross-sectional area of the gas flow will inevitably be compressed, resulting in poor air flow, and the soil accumulation area cannot be effectively heated. This example solves this problem well.

[0026] Furthermore, to solve the problem that the traditional jet holes 19 are easily blocked by fine soil particles, a composite anti-blocking structure is innovatively designed. As an example, the spiral coiled gas pipe 18 can be formed inside the inner cylinder, as Figure 5As shown, at this time, the jet port extends from the surface of the inner cylinder, and the comb-shaped enclosure 20 surrounds the jet port 19 to form a protective barrier. The jet port 19 is arranged radially, and shielding plates 21 are arranged at intervals in the direction directly opposite to it. A number of vertical poles are arranged at a certain distance around the jet port to form a comb-like structure, and the shielding plates are fixed on the top of the vertical poles. The shielding plates 21 are firmly connected to the comb-shaped enclosure 20, effectively preventing materials from directly impacting the jet port 19. The shielding plates 21 can block the front of the jet port 19 to prevent soil from directly entering. By setting the interval distance, the gas can collide with the shielding plates 21 and then spray out to the surroundings, and the comb-shaped enclosures around can play a role in intercepting the soil, and support a certain space on the jet port 19 so that the airflow can flow out smoothly, and the protruding enclosure can also exert a certain stirring effect on the soil to prevent soil caking.

[0027] As another example, Figure 6 As shown, an air jet is provided on the outer surface of the inner cylinder, and the spirally coiled air pipe 18 is provided with an air jet port. Of course, the spirally coiled air pipe 18 can also be provided as a spirally coiled air pipe 18 with a circular tube or a square tube cross-section.

[0028] As another embodiment, Figure 7 , 8 As shown, the spirally coiled air pipe 18 is further optimized into the form of 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, and the interior of the spiral conveying blade 22 is hollow to form an air pipe. A special structured air jet 19 is opened on the side away from the material inlet 15. The air jet 19 is composed of a conical protrusion 23 and a conical depression 24, and the bottom surfaces of the two are relative to each other to form an opening with clear directionality. The tip of the conical protrusion 23 points to the axis, and the tip of the conical recessed portion 24 is away from the axis. After the airflow is ejected through this opening, it is accurately shot to the inner wall surface of the inner cylinder 4, and the inner wall is continuously swept by the impact force of the airflow to prevent the material from adhering; at the same time, the conical protrusion 23 and the bottom surface of the conical recessed portion 24 extend to each other to form an anti-blocking shielding edge 26, which blocks the path of soil particles entering the air injection port 19 from the physical structure level, achieving a double anti-blocking effect; specifically, since the soil tends to fall and move from the center to the outside during feeding and rolling, the conical protrusion 23 is set with its front end pointing to the axis, which can form a similar effect to that in the spray The air opening 25 is provided with the effect of a protective shielding umbrella, and for soil diversion, the air jet opening 25 is directional, that is, the ejected gas is blown toward the side of the screen, thereby helping fine soil to be blown out of the screen and reach the outer annular chamber 5, thereby accelerating the separation efficiency of soil particles, and the conical recessed portion 24 recessed inward can have the effect of increasing the air jet opening 25; further, since it is set in the shape of a spiral conveying blade 22, it also has the axial conveying ability for the soil, and the steering direction 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.

[0029] In the actual implementation process, the installation of the spiral coiled gas pipe 18 needs to closely fit the contour of the inner cylinder body 4 to ensure that the spiral form is uniform. Taking a reactor with three layers of cylinder bodies (the second inner cylinder 10, the first inner cylinder 9, and the rotary cylinder body 1) as an example, when installing the spiral coiled gas pipe 18 on the inner surface of the second inner cylinder 10, the number of spiral turns and the pitch need to be accurately calculated according to the diameter and length of the cylinder body. Assuming that the diameter of the second inner cylinder 10 is 1 meter and the length is 10 meters, the spiral coiled gas pipe 18 can be set to wind 1.5 turns per meter, and the pitch is about 667 mm, so as to ensure that the heat source evenly covers the material. In the anti-blocking structure, the comb-shaped baffle part 20 is made of a high-temperature resistant alloy material, and the spacing between the comb teeth is set to 15 - 20 mm, which can effectively block large-particle materials without affecting the smooth ejection of the air flow; the spacing between the baffle plate 21 and the air jet port 19 is controlled within 30 - 50 mm to ensure that the air flow forms an effective buffer before impacting the material. In the design of the gas pipe in the shape of the spiral conveying blade 22, the height of the conical protrusion part 23 and the conical depression part 24 is set to 15 - 20 mm, and the bottom diameter is 25 - 35 mm. The angle of the air jet opening 25 formed by the combination of the two is controlled within 30° - 45°, so that the air flow blows towards the inner wall of the inner cylinder body 4 at the best angle.

[0030] 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 enables each layer of material to receive heat comprehensively and evenly. Compared with the traditional heat source input method, the heat transfer efficiency can be increased by more than 30%, effectively shortening the heat desorption treatment time. The innovative design of the anti-blocking structure greatly reduces the probability of blockage of the air jet port 19. Through simulation experiments, when treating contaminated soil with a fine particle content of up to 30%, the blockage frequency of the air jet port 19 is reduced from 5 - 8 times per hour in the traditional design to less than 1 time per 10 hours, significantly improving the continuous and stable operation ability of the equipment. The design of the gas pipe in the shape of the spiral conveying blade 22 realizes heat source injection while conveying the material, reduces the setting of additional conveying components, simplifies the equipment structure, and reduces the equipment manufacturing cost and maintenance difficulty. In addition, through the precise control of the angle of the air jet port 19 and the air flow direction, the phenomenon of local overheating or overcooling can be effectively avoided, and the temperature fluctuation range of the material is controlled within ±3°C, further improving the uniformity of the heat desorption treatment and the pollutant removal effect.

[0031] Example 3: As an improvement, in this embodiment, an integrated crushing device is embedded, effectively solving the industry pain point of low heat desorption efficiency of large-sized materials. This device takes the central rotating shaft 27 passing through the axis of the rotary cylinder body 1 as the core. As Figure 9 shown, a reverse-rotating shear crushing system is formed by the inner crushing knives 28 on the central rotating shaft 27 and the outer crushing knives 29 on the inner wall of the inner layer cylinder body, and the particle size is refined in real time during the material conveying process, laying an efficient foundation for the subsequent heat desorption process.

[0032] The crushing device uses the shear force and impact force generated by relative motion to achieve material crushing. The central rotating shaft 27 drives the inner crushing knife 28 to rotate, and its rotation speed can be controlled by the shaft driving part 30. Additionally, the shaft driving part 30 is an optional configuration. If the shaft driving part 30 is not set, the central shaft is a fixed shaft, and the relative motion of the crushing knife is formed by the rotation of the rotary cylinder 1 itself, thereby crushing the soil.

[0033] Furthermore, the inner crushing knife 28 and the outer crushing knife 29 fixed on the inner wall of the inner cylinder form an interleaved crushing space. When large pieces of material enter this area, they will be blocked and cut by both the inner crushing knife 28 and the outer crushing knife 29, and are torn and crushed under the dual action. This design of reverse rotation can produce a multi-dimensional crushing effect. It can not only tear the material axially but also form a 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.

[0034] 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 processing capacity of the rotary kiln. Taking a rotary kiln with a processing capacity of 5 tons per hour as an example, the diameter of the central rotating shaft 27 can be set to 120 - 150 mm, which can not only ensure sufficient torque transmission but also avoid affecting the internal space layout due to too large a shaft diameter. The central rotating shaft 27 is rotationally installed between the kiln head cover 2 and the kiln tail cover 3 through high-precision bearings, and the bearings need to have the characteristics of high temperature resistance and high load to adapt to the complex working conditions inside the rotary kiln. The shaft driving part 30 can select a driving scheme of a variable-frequency motor combined with a reducer to flexibly adjust the rotation speed according to the material characteristics. The inner crushing knife 28 adopts a detachable modular design, with a knife body length of 200 - 300 mm and a blade thickness of 15 - 20 mm, and is fixed on the central rotating shaft 27 through bolts, facilitating rapid replacement after wear; the outer crushing knife 29 is directly welded to the inner wall of the inner cylinder, with a knife body length adapted to the inner crushing knife 28, and the blade angle is designed to be 45° - 60° to optimize the shear effect.

[0035] The application of this integrated crushing device brings good effects to the rotary kiln reactor. In terms of processing efficiency, through actual tests, when treating contaminated soil containing 20% - 30% of particles with a diameter greater than 50 mm, the average particle size of the crushed material can be reduced to less than 20 mm, and the thermal desorption efficiency is increased by 25% - 35%, effectively reducing the secondary treatment cost caused by the residue of large pieces of material. In addition, the integrated design does not require an additional crushing space, and realizes function upgrading without changing the overall size of the rotary kiln, which has extremely high practical value for pollution remediation projects with limited space. Through the variable-frequency speed regulation system, the crushing intensity can be adjusted in real time for materials with different hardness and humidity, and the equipment applicable range covers various pollution media from cohesive soil to sandy soil, significantly improving the versatility and adaptability of the rotary kiln reactor.

[0036] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A thermal desorption multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution, characterized in that: The rotary cylinder comprises a rotary cylinder, which is arranged between a kiln head cover and a kiln tail cover in a relatively rotating manner, and a plurality of inner cylinders are arranged inside the rotary cylinder, and each inner cylinder is arranged in a mutually sleeved manner from the inside to the outside along the axial direction, and the diameter of the plurality of inner cylinders gradually increases from the inside to the outside, and the plurality of inner cylinders divide the interior of the rotary cylinder into a plurality of annular chambers, and a sieve hole is arranged on the side wall of the inner cylinder, and the sieve hole on the inner inner cylinder is larger than the sieve hole on the outer inner cylinder; The kiln tail hood and the kiln head hood are provided with gas inlets and gas outlets according to the preset airflow direction. The rotating cylinder is provided with a side wall chamber heat source input structure, which forms a multi-point surrounding heat source input corresponding to the annular chamber in the rotating cylinder, so that the heat source acts directly and evenly on the materials between each layer.

2. The thermal desorption multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution according to claim 1 is characterized in that: The multi-layer inner cylinder comprises a first inner cylinder and a second inner cylinder. The first inner cylinder is fixed inside the rotating 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 mesh of the first screen is larger than the mesh of the second screen. A material inlet is arranged on the kiln head cover, and the material inlet is connected to one end of the second inner cylinder, and the other end of the second inner cylinder is a material discharge end.

3. The thermal desorption multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution according to claim 1 is characterized in that: The multi-layer inner cylinder is designed with a diameter of each layer gradually increasing from the inside to the outside, and the ratio of the outer cylinder diameter to the inner cylinder diameter is determined according to the Fibonacci sequence.

4. The thermal desorption multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution according to claim 1 is characterized in that: The aperture of the sieve holes arranged on the side wall of the inner cylinder matches the material particle distribution, and the aperture of the sieve holes is 1-1.05 times the designed material diameter of the corresponding material layer; An angle is formed between the central axis of the rotating cylinder and the horizontal plane, and the angle is 0°-3°.

5. The thermal desorption multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution according to claim 1, characterized in that: The side wall chamber heat source input structure comprises a spirally coiled air pipe arranged around the surface of the inner cylinder, and a jet nozzle is arranged on the side wall of the spirally coiled air pipe.

6. The thermal desorption multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution according to claim 5, characterized in that: An anti-blocking structure is provided at the corresponding jet port, and the anti-blocking structure includes a comb-shaped enclosure. The jet direction of the jet port is arranged radially, and shielding plates are arranged at intervals in the direction opposite to the jet port. The shielding plates are fixed on the surrounding comb-shaped enclosure.

7. The thermal desorption multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution according to claim 5, characterized in that: The spirally coiled air pipe is coiled on the inner surface of the inner cylinder, and the spirally coiled air pipe is protruded from the surface of the inner cylinder to form a spiral conveying blade arranged on the inner cylinder. The spiral conveying blade formed by the spirally coiled air pipe is provided with an air jet on the side away from the material inlet, and the air jet includes a conical protrusion and a conical depression, the tip of the conical protrusion points to the axis, and the tip of the conical depression points away from the axis, and the bottom sides of the conical protrusion and the conical depression relatively form a directional air jet opening; the airflow ejection direction of the air jet opening is directed to the inner wall surface of the inner cylinder; and the bottom side of the conical depression extends toward the tip of the conical protrusion, and similarly, the bottom side of the conical protrusion extends toward the tip of the conical depression, so that the portion extending from the bottom surface of the conical protrusion forms an anti-blocking shielding edge for the air jet opening.

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

9. The thermal desorption multi-layer cylindrical rotary kiln reactor for rapid remediation of site pollution according to claim 8, characterized in that: The central rotating shaft is rotatably arranged between the kiln head cover and the kiln tail cover, and a shaft driving part for driving the central shaft to rotate is arranged at either end.

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