Heat transfer device for a direct thermal desorption reactor

Abstract

The present application relates to a kind of heat transfer devices of direct thermal desorption reactor, including transverse arrangement heat transfer body, the heat transfer body is connected with reactor inner cylinder by branch wing, one side of the heat transfer body is towards the center of rotary kiln primary air nozzle, wind power dispersion structure is provided on the heat transfer body.The advantage of the present application is that by installing heat transfer device in thermal desorption reactor, not only the flow direction of primary air is changed, the airflow is more dispersed, uniform, the heat exchange efficiency is improved, and the heat transfer device itself is a kind of good heat transfer material, the soil scooped up by scoop plate can be directly contacted with heat transfer device and heat exchange, further improve the heat transfer efficiency.

Description

Technical Field

[0001] This invention relates to a heat transfer device, and more particularly to a heat transfer device for a direct thermal desorption reactor. Background Technology

[0002] With the adjustment of my country's industrial structure and urbanization, a large number of pesticide and chemical enterprises have relocated, leaving behind a large number of organically contaminated sites, posing serious environmental risks and urgently requiring rapid and effective remediation. Direct thermal desorption (DFD) technology has advantages such as a wide treatment range, high heat exchange efficiency, and large processing capacity, making it one of the main technologies for the remediation of organically contaminated sites. DFD technology involves pre-treating contaminated soil through crushing and screening before feeding it into a thermal desorption unit. The high-temperature primary air generated by combustion comes into contact with the soil and exchanges heat, causing the pollutants in the soil to volatilize into a gaseous state and separate from the solid soil, thus achieving the purpose of soil remediation. A typical DFD system consists of a feeding device, a rotary kiln, a discharge device, a waste heat recovery device, a tail gas purification device, a wastewater treatment device, an electrical and automatic control system, and other auxiliary equipment. Among these, the rotary kiln reactor is the core component. The rotary kiln's rotating drum, acting as a mass and heat transfer reactor, is a rotating component. It has one end for feeding and the other for discharging. The soil to be treated slides into the drum from the feed chute at the feed end by its own weight and flows out of the discharge end through the open outlet by gravity. The drum's diameter is over 1 meter, with a maximum diameter of approximately 5 meters. Due to the large diameter, the primary air ejected from the discharge end of the rotary kiln cannot be evenly distributed throughout the drum. The internal temperature field of the kiln exhibits a pattern of high temperature in the center and low temperature around the edges, while the soil, due to gravity, constantly rotates along the inside of the drum. Therefore, the heat transfer performance of the primary air is poor, resulting in poor direct thermal desorption. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a heat transfer device for a direct thermal desorption reactor, including a heat transfer body arranged laterally, the heat transfer body being connected to the inner cylinder of the reactor through a support wing, one side of the heat transfer body facing the center of the primary air nozzle of the rotary kiln, and an air force dispersion structure being provided on the heat transfer body.

[0004] The further optimized technical solution of this invention is as follows:

[0005] Preferably, the heat transfer body is a conical body, which is connected to the inner cylinder of the reactor through a support wing. The conical body has a hollow interior and an open bottom surface. The open bottom surface of the conical body faces the center of the primary air nozzle of the rotary kiln, and its side surface has a porous structure. A set of air holes is provided on the side surface of the conical body.

[0006] With the above structure, primary air enters from the bottom of the cone and exits from the porous structure on the side, forming a uniform and dispersed airflow that contacts and exchanges heat with the particles to be treated. Simultaneously, the soil lifted by the lifting plate directly contacts the heat transfer enhancement device, increasing the heat exchange effect.

[0007] Preferably, the heat transfer body is a cylindrical body with an open bottom and a closed top, and is a hollow internal structure. The open bottom of the cylindrical body faces the center of the primary air nozzle of the rotary kiln, and a set of air holes are provided on the side of the cylindrical body.

[0008] With the above structure, primary air enters from the bottom of the cylindrical body and exits from the porous structure on the side, forming a uniform and dispersed airflow that contacts and exchanges heat with the soil to be treated. At the same time, the soil lifted by the lifting plate directly contacts the cylindrical body, increasing the heat exchange effect.

[0009] Preferably, the heat transfer body is a frustum structure, with a conical hole on the top surface of the frustum structure, and the top surface of the frustum structure faces the center of the primary air nozzle of the rotary kiln.

[0010] With the above structure, the primary air is sprayed towards the top surface of the truncated cone. After impacting the truncated cone, it is dispersed into multiple streams of air that flow away from the periphery of the truncated cone, forming a uniform and dispersed airflow that comes into contact with the particles to be treated and exchanges heat.

[0011] Preferably, at least one set of uniformly arranged support wings are provided on the outer circumference of the heat transfer body, one end of the support wing is connected to the heat transfer body, and the other end is opened and installed on the inner wall of the reactor.

[0012] In this way, the heat transfer device is fixed in the inner cylinder of the reactor by multiple supports.

[0013] Preferably, each group of support wings has 4 wings, and the included angle between two adjacent support wings is 90°.

[0014] Preferably, the heat transfer body is made of a corrosion-resistant and high-temperature-resistant material, preferably stainless steel or silicon carbide ceramic.

[0015] Preferably, the inner diameter of the bottom surface of the heat transfer body is 0.4 to 0.5 times the inner diameter of the thermal desorption reactor.

[0016] This ensures sufficient heat transfer efficiency without causing soil to accumulate and clog around the heat transfer body.

[0017] Preferably, the diameter of the air vent is 10-15 cm.

[0018] This ensures that soil particles falling onto the heat transfer body can fall smoothly to the bottom of the cylinder through the air vents.

[0019] Preferably, a set of lifting plates is provided on the inner wall of the reactor inner cylinder, the height of the heat transfer body is 1.2 to 1.5 times the width of the lifting plates, and the height of the lifting plates is 0.5 to 0.7 times the height of the reactor rotating cylinder.

[0020] This ensures that a large number of soil particles can be scooped up and fall onto the heat transfer body.

[0021] The advantage of this invention is that by installing a heat transfer device in the thermal desorption reactor, not only is the direction of the primary air flow changed, making the airflow more dispersed and uniform, thus improving the heat exchange efficiency, but the heat transfer device itself is also a good heat transfer material. The soil lifted by the lifting plate can directly contact the heat transfer device and exchange heat, further improving the heat transfer efficiency. Attached Figure Description

[0022] Figure 1 This is an installation diagram of Embodiment 1 of the present invention.

[0023] Figure 2 This is a front view of Embodiment 1 of the present invention.

[0024] Figure 3 This is an installation diagram of Embodiment 2 of the present invention.

[0025] Figure 4 This is a front view of Embodiment 2 of the present invention.

[0026] Figure 5 This is an installation diagram of Embodiment 3 of the present invention.

[0027] Figure 6 This is a front view of Embodiment 3 of the present invention.

[0028] In the figure: 1. Reactor inner cylinder, 2. Lifting plate, 3. Support wing, 4. Conical body, 5. Cylindrical body, 6. Frustum structure, 601. Conical hole. Detailed Implementation

[0029] Example 1

[0030] This embodiment provides a heat transfer device installed inside the inner cylinder of a direct thermal desorption reactor, and its structure is as follows: Figure 1 and Figure 2As shown, the reactor includes a transversely arranged conical body 4 with an air dispersion structure. The conical body 4 is formed by rolling a fan-shaped plate, which is made of stainless steel or silicon carbide ceramic. The conical body 4 is connected to the inner cylinder 1 of the reactor via a support wing 3. A lifting plate 2 is provided on the inner wall of the inner cylinder 1. The height of the conical body 4 is 1.2 to 1.5 times the width of the lifting plate 2, and the inner diameter of the bottom surface of the conical body 4 is 0.3 to 0.6 times the inner diameter of the thermal desorption reactor. The installation position of the conical body 4 is on the same cross section as the lifting plate 2. The conical body 4 is a hollow structure with an open bottom surface. The open bottom surface of the conical body 4 faces the center of the primary air nozzle of the rotary kiln, serving as the air inlet of the conical body 4. The conical body 4 has a porous structure on its sides, with several air holes of 10-15 cm in diameter. These air holes serve as a wind dispersion structure on the conical body 4, dispersing the powerful air jet from the primary air nozzle into a uniform flow. Four evenly arranged support wings 3 are located on the outer circumference of the bottom surface of the conical body 4. The included angle between adjacent support wings 3 is 90°. One end of each support wing 3 is connected to the conical body 4, while the other end is perforated and installed on the inner wall of the reactor, thus fixing the heat transfer device within the reactor's inner cylinder via the support wings 3.

[0031] During operation, primary air ejected from the discharge end of the rotary kiln enters the rotating drum and then passes through the open bottom surface of the conical body 4. It is then ejected from the porous structure on the side of the conical body 4, forming a uniform and dispersed airflow within the rotating drum. This airflow serves to distribute the air and facilitates contact and heat exchange with the particles to be processed within the drum. Simultaneously, the soil lifted by the lifting plates 2 directly contacts the conical body 4, further enhancing the heat exchange effect.

[0032] Example 2

[0033] This embodiment provides a heat transfer device installed in the inner cylinder of a direct thermal desorption reactor, the structure of which is as follows: Figure 3 and Figure 4As shown, the reactor includes a horizontally arranged cylindrical body 5 with an airflow dispersion structure. The cylindrical body 5 is made of a square sheet rolled up, which is made of stainless steel or silicon carbide ceramic. The cylindrical body 5 is connected to the inner cylinder 1 of the reactor via a support wing 3. A lifting plate 2 is provided on the inner wall of the inner cylinder 1. The height of the cylindrical body 5 is 0.5 to 0.7 times the height of the inner cylinder 1, and the inner diameter of the bottom surface of the cylindrical body 5 is 0.4 to 0.5 times the inner diameter of the thermal desorption reactor. The cylindrical body 5 has an open bottom and a closed top, hollow internal structure. The open bottom surface of the cylindrical body 5 faces the center of the primary air nozzle of the rotary kiln, serving as the air inlet of the conical body 4. The sides of the cylindrical body 5 have a porous structure with several air holes, each with a diameter of 10 to 15 cm. These air holes serve as the airflow dispersion structure on the cylindrical body 5, dispersing the strong air jet from the primary air nozzle into a uniform airflow. The outer circumference of the cylindrical body 5 is provided with four sets of evenly distributed support wings 3. Each set of support wings 3 has 4 wings. The included angle between two adjacent support wings 3 is 90°. One end of the support wing 3 is connected to the cylindrical body 5, and the other end is opened and installed on the inner wall of the reactor, so that the heat transfer device is fixed in the inner cylinder of the reactor through the four sets of support wings 3.

[0034] During operation, primary air ejected from the discharge end of the rotary kiln enters the rotating drum and then passes through the open bottom surface of the cylindrical body 5. It is then ejected from the porous structure on the side of the cylindrical body 5, forming a uniform and dispersed airflow within the rotating drum. This facilitates contact and heat exchange with the particles to be processed inside the drum. Simultaneously, the soil lifted by the lifting plates 2 directly contacts the cylindrical body 5, further enhancing the heat exchange effect.

[0035] Example 3

[0036] This embodiment provides a heat transfer device installed in the inner cylinder of the direct thermal desorption reactor, the structure of which is as follows: Figure 5 and Figure 6 As shown, the reactor includes a transversely arranged frustum structure 6. A wind dispersion structure is provided on the side of the frustum structure 6 facing the primary air nozzle. The frustum structure 6 is made of corrosion-resistant and high-temperature-resistant material, preferably stainless steel or silicon carbide ceramic. The frustum structure 6 is connected to the reactor inner cylinder 1 via a support wing 3. The inner diameter of the bottom surface of the frustum structure 6 is 0.4 to 0.5 times the inner diameter of the thermal desorption reactor. A conical hole 601 is opened on the top surface of the frustum structure 6, facing the center of the primary air nozzle of the rotary kiln. The conical hole 601 corresponds to the primary air nozzle and serves as the wind dispersion structure on the frustum structure 6, used to disperse the powerful air jet ejected from the primary air nozzle into a uniform airflow through impact. Four evenly distributed support wings 3 are provided on the outer circumference of the frustum structure 6. The included angle between two adjacent support wings 3 is 90°. One end of the support wing 3 is connected to the frustum structure 6, and the other end is opened and installed on the inner wall of the reactor, so that the heat transfer device is fixed in the inner cylinder of the reactor through the support wings 3.

[0037] During operation, the primary air ejected from the discharge end of the rotary kiln enters the rotating drum and is sprayed toward the top surface of the truncated cone structure 6. After impacting the truncated cone structure 6, it disperses into multiple streams of airflow that flow away from the periphery of the truncated cone structure 6, forming a uniform and dispersed airflow inside the rotating drum, which facilitates contact and heat exchange with the particles to be processed inside the rotating drum.

[0038] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A rotary kiln for direct thermal desorption reactions, characterized in that: The rotary kiln is equipped with a heat transfer device, which includes a heat transfer body arranged laterally. The heat transfer body is connected to the inner cylinder of the rotary kiln through support wings. One side of the heat transfer body faces the center of the primary air nozzle of the rotary kiln. The heat transfer body is provided with an air force dispersion structure. At least one set of evenly arranged support wings is provided on the outer circumference of the heat transfer body. One end of the support wing is connected to the heat transfer body, and the other end is opened and installed on the inner cylinder wall of the rotary kiln. The heat transfer body is a conical body with a hollow interior and an open bottom. The open bottom of the conical body faces the center of the primary air nozzle of the rotary kiln, and a set of air holes is provided on the side of the conical body. Alternatively, the heat transfer body is a cylindrical body with a hollow interior, an open bottom, and a closed top. The open bottom of the cylindrical body faces the center of the primary air nozzle of the rotary kiln, and a set of air holes is provided on the side of the cylindrical body. Alternatively, the heat transfer body is a frustum structure with a conical hole on the top surface of the frustum structure, and the top surface of the frustum structure faces the center of the primary air nozzle of the rotary kiln. A set of lifting plates is provided on the inner wall of the inner cylinder of the rotary kiln.

2. The rotary kiln for direct thermal desorption reaction according to claim 1, characterized in that: Each group of support wings has 4 wings, and the angle between any two adjacent support wings is 90°.

3. The rotary kiln for direct thermal desorption reaction according to claim 1, characterized in that: The heat transfer body is made of stainless steel or silicon carbide ceramic.

4. The rotary kiln for direct thermal desorption reaction according to claim 1, characterized in that: The inner diameter of the bottom surface of the heat transfer body is 0.4 to 0.5 times the inner diameter of the thermal desorption reactor.

5. The rotary kiln for direct thermal desorption reaction according to claim 1, characterized in that: The diameter of the air vent is 10-15 cm.

6. The rotary kiln for direct thermal desorption reaction according to claim 1, characterized in that: The height of the heat transfer body is 1.2 to 1.5 times the width of the lifter plate, and the height of the lifter plate is 0.5 to 0.7 times the height of the reactor drum.

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