Heating device for heat-assisted vacuum desorption

Abstract

The invention relates to the technical field of adsorption and desorption in environment-friendly waste gas treatment, and particularly discloses a heating device for heat-assisted vacuum desorption, which comprises a vacuum desorption box, an adsorption bed is arranged in the vacuum desorption box, and support plates are arranged at openings on two opposite sides of the vacuum desorption box; the PTC heating components are horizontally and vertically inserted into the adsorption bed and are distributed in an upper layer, a middle layer and a lower layer; the two side flow guide mechanisms are arranged in the vacuum desorption box; the transmission mechanism is arranged among the multiple flow guide shafts distributed on the same layer; the driving mechanism is arranged on the side wall of the vacuum desorption box; the drainage structure is used for communicating the exhaust pipe with the flow guide mechanism. According to the invention, the uniformity and the accuracy of the temperature in the whole desorption process are improved, the purposes of eliminating the overheating risk, improving the desorption safety and simplifying the temperature control are realized, and the efficient utilization of heat energy is realized, so that the overall energy consumption in the desorption process is reduced, and the efficient and uniform regeneration of the adsorbent at a lower temperature is realized.

Description

Technical Field

[0001] This invention relates to the field of adsorption and desorption technology for environmental waste gas treatment, specifically to a heating device for heat-assisted vacuum desorption. Background Technology

[0002] Vacuum desorption of adsorbent materials involves reducing the partial pressure of the adsorbate in the gas phase surrounding the adsorbent by creating a vacuum, thus desorbing the adsorbate from the adsorbent surface. In practical applications, vacuum desorption alone is ineffective for most adsorbent materials, and the residual pollutants formed from incomplete desorption can accumulate with each adsorption-desorption cycle. Considering that vacuum desorption efficiency is affected by vacuum level, desorption temperature, and adsorbent-adsorbate binding energy, a higher vacuum level combined with increased desorption temperature is generally used to achieve higher desorption efficiency; this method is known as thermally assisted vacuum desorption technology.

[0003] In a vacuum environment, due to the lack of a gaseous medium, convective heat transfer is almost zero. Therefore, heat transfer in a vacuum environment mainly occurs through thermal conduction and thermal radiation. Current limitations of related technologies include:

[0004] 1. Uneven heat transfer in the bed: The high porosity of the adsorbent bed and the discontinuous heat conduction path easily generate local hot spots and temperature gradients, resulting in uneven desorption;

[0005] 2. Low efficiency of indirect heat exchange: Although indirect heat exchange (such as steam or hot air) is safer, it has low heat transfer efficiency, large heat loss, complex temperature control, and high energy consumption.

[0006] 3. Direct radiation temperature control is difficult: Radiation methods such as microwave heating make it difficult to control the temperature precisely. Excessively high desorption temperatures can damage the adsorbent's performance and pose safety hazards. Summary of the Invention

[0007] To address the aforementioned problems in the existing technology, such as low heat transfer efficiency, inaccurate temperature control, significant safety hazards, and high energy consumption during heat-assisted vacuum desorption, this invention provides a heating device with a simple structure and convenient operation. This device can easily and effectively control the desorption temperature in a vacuum environment, improve desorption safety, provide efficient heating, and save energy.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A heating device for heat-assisted vacuum desorption, comprising:

[0010] A vacuum desorption chamber is provided with an adsorption bed inside. Support plates are provided on both sides of the vacuum desorption chamber, and the adsorption bed is located between the two support plates.

[0011] The PTC heating element is inserted horizontally and vertically into the adsorption bed and is distributed in three layers (upper, middle, and lower) along the height of the bed to achieve gradient heating or zoned temperature control.

[0012] The flow guiding mechanisms on both sides are located inside the vacuum desorption chamber;

[0013] The transmission mechanism is located between multiple guide shafts distributed in the same layer;

[0014] The drive mechanism is located on the side wall of the vacuum desorption chamber;

[0015] A flow-guiding structure is used to connect the exhaust pipe and the flow-guiding mechanism;

[0016] The multi-layer PTC heating components provide a uniform, precise, and intrinsically safe main thermal field that can automatically reduce heating power when the temperature rises. Based on this thermal field, two sets of drive motors and corresponding transmission mechanisms drive the flow guiding mechanisms located at different heights to perform reverse flow, thereby creating tumbling within the adsorption bed. This synergistically achieves the goals of eliminating overheating risks, improving desorption safety, and simplifying temperature control.

[0017] Preferably, the bottom of the vacuum desorption chamber is provided with an air inlet pipe, and the top of the vacuum desorption chamber is provided with an exhaust pipe.

[0018] Preferably, the PTC heating assembly includes: a plurality of PTC heating rods and a vacuum flange, wherein the PTC heating rods are horizontally and vertically inserted into the adsorption bed through the vacuum flange, and the outer wall of the PTC heating rods is coated with a carbon nanomaterial composite layer, wherein the carbon nanomaterials include: graphene and carbon nanotubes.

[0019] Preferably, the PTC heating rod includes a heat-conducting pipe and a ceramic element, wherein the ceramic element is sleeved inside the heat-conducting pipe.

[0020] Preferably, the flow guiding mechanism includes: multiple flow guiding shafts rotatably mounted between two support plates. The flow guiding shafts are vertically arranged at the center of a rectangular area composed of four PTC heating rods, forming a composite matrix that is staggered with the PTC heating rod array. The outer wall of the flow guiding shaft is provided with spiral blades, and one of the support plates is provided with a flow guiding box on its side wall. The flow guiding box is rotatably connected to the flow guiding shaft.

[0021] Preferably, the guide shaft is a hollow tube with one end open as a medium inlet. Multiple guide holes or injection holes communicating with the internal cavity are distributed on the tube wall to convert the medium from axial flow to radial diffusion.

[0022] Preferably, the flow guide box is arranged in a "U" shape, the open end of the flow guide shaft is rotatably connected to the flow guide box through a bushing, and the side wall of the support plate is provided with a plurality of sealing bushings, which are rotatably connected to the flow guide shaft.

[0023] Preferably, the transmission mechanism includes a pulley and a timing belt, wherein the pulley is disposed on the side wall of the guide shaft, and the timing belt is wound between two adjacent pulleys.

[0024] Preferably, the drive mechanism includes a servo motor, and two support frames are provided on the side wall of the support plate near the transmission mechanism. The servo motor is provided on the side wall of the support frame, and the output shaft of the servo motor is fixedly connected to the end of the guide shaft through a coupling.

[0025] Preferably, the drainage structure includes: a drainage pipe, one end of which is connected to the drainage box, and the other end of which is connected to the exhaust pipe through a T-connector; a first solenoid valve is provided on the side wall of the drainage pipe, and a second solenoid valve is provided on the side wall of the exhaust pipe.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. By directly and vertically inserting a multi-layer PTC heating rod array into the adsorption bed and applying a neural network-based intelligent control algorithm, the system can precisely perform the following operations: releasing heat from the core of the bed outwards; simultaneously, based on real-time feedback from independent temperature control zones in the upper, middle, and lower layers and built-in thermocouples, dynamic learning and decision-making are conducted to adjust the power of each zone. This algorithm intelligently models and compensates for the discontinuity in heat conduction caused by bed porosity, thereby proactively and reliably avoiding the formation of local overheating or cold spots. The PTC heating rod's metal shell directly contacts the adsorbent particles, eliminating inefficient indirect heating methods. Wall heat exchange establishes the shortest and most efficient heat conduction path. As the temperature of the PTC heating rod increases, the resistance automatically increases and the power decreases, which can eliminate the risk of overheating, significantly improve desorption safety, save energy, simplify temperature control, and reduce the failure rate of the vacuum system. At the same time, a high infrared emissivity coating such as graphene-carbon nanotubes is applied to the outer wall of the heating rod. Utilizing its high thermal conductivity and chemical stability, the contact thermal resistance between the adsorbent and the heating rod is reduced, maximizing infrared radiation output in a vacuum environment and directly and efficiently transferring heat to the adsorbent, greatly reducing the multi-layer thermal resistance and heat loss along the way in traditional methods.

[0028] The beneficial effects are: improved temperature uniformity and accuracy throughout the desorption process, efficient utilization of thermal energy, and thus reduced overall energy consumption of the desorption process.

[0029] 2. By controlling the first solenoid valve on the sidewall of the inlet pipe and the second solenoid valve on the sidewall of the exhaust pipe, a portion of the high-concentration desorption vapor collected from the agitation zone can be efficiently injected into the main exhaust system, forming a closed-loop cycle for enhanced desorption. Throughout the process, vacuuming is used to reduce the partial pressure of the adsorbate in the gas phase surrounding the adsorbent, thereby driving the adsorbate to desorb from the adsorbent surface; heating serves as an auxiliary power source, providing the necessary energy to overcome the adsorption barrier and accelerate this desorption process, thus achieving efficient, uniform, and thorough regeneration of the adsorbent at a lower temperature.

[0030] The beneficial effect is that it enables efficient and uniform regeneration of the adsorbent at a lower temperature.

[0031] 3. Through two sets of drive mechanisms and their transmission mechanisms, the flow guiding mechanisms located at different heights are driven to rotate in opposite directions or in the opposite direction, so that the spiral blades agitate the adsorption bed, which completely breaks the heat conduction barrier caused by the high porosity of the bed, realizes the uniform diffusion of heat in three-dimensional space, and overcomes the temperature gradient problem; the mechanical agitation continuously agitates the deep adsorbent to the effective heating zone, thereby significantly reducing desorption residues and ensuring regeneration stability.

[0032] The beneficial effects are: reduced system energy consumption and reduced risk of adsorbent thermal degradation. Attached Figure Description

[0033] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0034] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0035] Figure 2 This is an exploded view of the vacuum desorption chamber in this invention;

[0036] Figure 3 This is a diagram showing the installation structure of the drive mechanism in this invention;

[0037] Figure 4 This is a distribution diagram of the PTC heating rods in this invention;

[0038] Figure 5 This is a cross-sectional view of the PTC heating rod in this invention;

[0039] Figure 6 This is an installation structure diagram of the transmission mechanism and the drainage structure in this invention.

[0040] Explanation of reference numerals in the attached figures:

[0041] In the picture:

[0042] 1. Vacuum desorption chamber; 2. Support plate; 3. Inlet pipe; 4. Exhaust pipe;

[0043] 11. Heat pipe; 12. Ceramic components; 13. Vacuum flange;

[0044] 21. Guide shaft; 22. Spiral blade; 23. Guide box; 24. Sealing bushing;

[0045] 31. Pulley; 32. Timing belt;

[0046] 41. Support frame; 42. Servo motor;

[0047] 51. Drainage tube; 52. First solenoid valve; 53. Second solenoid valve. Detailed Implementation

[0048] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the specific implementation methods, structures, features, and effects of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and preferred embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] In the description of this application, it should be understood that the orientation or positional relationship indicated by terms such as "inner" and "outer" are based on the orientation or position shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, a specific orientation structure and operation, and therefore should not be construed as a limitation of this application.

[0050] Example 1:

[0051] Reference Figures 1-6 The present invention discloses a heating device for heat-assisted vacuum desorption, comprising:

[0052] In order to realize the basic reaction vessel and gas flow channel functions of heat-assisted vacuum desorption, in this embodiment: the vacuum desorption box 1 is provided with an adsorption bed inside, and support plates 2 are provided on both sides of the open opening of the vacuum desorption box 1. The adsorption bed is located between the two support plates 2. The bottom of the vacuum desorption box 1 is provided with a communicating air inlet pipe 3, and the top of the vacuum desorption box 1 is provided with an exhaust pipe 4.

[0053] To achieve a uniform, precise, and intrinsically safe main heat source from inside the adsorption bed, in this embodiment: a PTC heating assembly is inserted horizontally and vertically into the adsorption bed, and is distributed in three layers (upper, middle, and lower) along the height of the bed to achieve gradient heating or zoned temperature control. The PTC heating assembly includes: multiple PTC heating rods and a vacuum flange 13. The PTC heating rods are inserted horizontally and vertically into the adsorption bed through the vacuum flange 13. The outer wall of the PTC heating rod is coated with a carbon nanomaterial composite layer, including: graphene and carbon nanotubes. The PTC heating rod includes: a heat-conducting pipe 11 and a ceramic element 12, with the ceramic element 12 sleeved inside the heat-conducting pipe 11.

[0054] To introduce controllable mechanical agitation and enhanced gas extraction channels within the adsorption bed to improve heat and mass transfer, in this embodiment: a two-layer flow guiding mechanism is installed inside the vacuum desorption chamber 1. The flow guiding mechanism includes multiple flow guiding shafts 21, rotatably mounted between two support plates 2. The flow guiding shafts 21 are vertically arranged at the center of a rectangular area composed of four PTC heating rods, forming a composite matrix interleaved with the PTC heating rod array. The flow guiding shafts 21 are hollow tubes, with one end open as a medium inlet. The upper part has multiple guide holes or injection holes that communicate with the internal cavity to convert the medium from axial flow to radial diffusion. The outer wall of the guide shaft 21 is provided with a spiral blade 22. One of the support plates 2 has a guide box 23 on its side wall. The guide box 23 is rotatably connected to the guide shaft 21. The guide box 23 is arranged in a "U" shape. The open end of the guide shaft 21 is rotatably connected to the guide box 23 through a bushing. The side wall of the support plate 2 is provided with multiple sealing bushings 24. The sealing bushings 24 are rotatably connected to the guide shaft 21.

[0055] In order to achieve synchronous movement among multiple guide shafts 21 in the same layer and ensure the uniformity of the stirring force field, in this embodiment: a transmission mechanism is set among multiple guide shafts 21 distributed in the same layer. The transmission mechanism includes: pulleys 31 and synchronous belts 32. The pulleys 31 are set on the side wall of the guide shafts 21, and the synchronous belts 32 are wound between two adjacent pulleys 31.

[0056] In order to provide controllable rotational power to the flow guide mechanism and realize layered independent drive, in this embodiment: the drive mechanism is set on the side wall of the vacuum desorption box 1. The drive mechanism includes a servo motor 42. Two support frames 41 are set on the side wall of the support plate 2 near the transmission mechanism. The servo motor 42 is set on the side wall of the support frame 41. The output shaft of the servo motor 42 is fixedly connected to the shaft end of the flow guide shaft 21 through a coupling.

[0057] In order to efficiently guide some of the desorbed vapor from the agitation area to the main exhaust system and enhance the extraction channel, in this embodiment: a diversion structure is used to connect the exhaust pipe 4 and the diversion mechanism. The diversion structure includes: a diversion pipe 51, one end of which is connected to the diversion box 23, and the other end of which is connected to the exhaust pipe 4 through a three-way connector. A first solenoid valve 52 is provided on the side wall of the diversion pipe 51, and a second solenoid valve 53 is provided on the side wall of the exhaust pipe 4.

[0058] The working principle and usage process of this invention are as follows: First, the waste gas to be treated enters the vacuum desorption chamber 1 through the inlet pipe 3 and flows through the adsorption bed located between the two support plates 2. The pollutants are captured by the adsorbent. During the desorption stage, the inlet pipe 3 and the exhaust pipe 4 are closed, and the vacuum system is started to evacuate the chamber. The core desorption process then begins, and the multi-layered PTC heating components start working. Multiple PTC heating rods are inserted horizontally and vertically into the adsorption bed through the vacuum flange 13 and are distributed in three layers (upper, middle, and lower) along the height of the bed to achieve gradient heating or zoned temperature control. The PTC heating rod consists of an internal ceramic element 12 and a heat-conducting pipe 11 sleeved on it. Its outer wall is coated with a carbon nanomaterial composite layer containing graphene and carbon nanotubes. This design enables it to provide a uniform, precise, and intrinsically safe main thermal field from the core of the adsorption bed through efficient thermal radiation and conduction in a vacuum environment.

[0059] Meanwhile, to enhance heat and mass transfer, the two-layer flow guiding mechanism set in the vacuum desorption chamber 1 begins to work together. Each layer of flow guiding mechanism includes multiple flow guiding shafts 21 rotatably mounted between the support plates 2. These flow guiding shafts 21 are vertically arranged at the center of the rectangular area composed of four PTC heating rods, thus forming a spatially interlaced composite matrix with the heating rod array. The drive mechanism starts to operate. Specifically, the output shaft of the servo motor 42 drives the flow guiding shafts 21 to rotate via a coupling. Through the pulley 31 mounted on the shaft side and the synchronous belt 32 wound around it, it is ensured that all flow guiding shafts 21 in the same layer rotate synchronously. The key is that through two sets of independent drive mechanisms and corresponding transmission mechanisms, the flow guiding mechanisms located at the upper and lower layers can be driven to rotate in opposite directions or in the opposite direction.

[0060] When the guide shaft 21 rotates, the spiral blades 22 on its outer wall agitate the surrounding adsorbent, disrupting the heat and mass transfer boundary layer. Simultaneously, the guide shaft 21, acting as a hollow tube, has one end open as a medium inlet and rotates in connection with the guide box 23. Under vacuum suction, some of the pollutant vapor generated during desorption can be drawn into the internal cavity through the guide holes or injection holes distributed on the tube wall of the guide shaft 21, achieving radial to axial flow from the bed. By controlling the first solenoid valve 52 on the side wall of the guide pipe 51 and the second solenoid valve 53 on the side wall of the exhaust pipe 4, a portion of the high-concentration desorption vapor collected from the agitation zone can be efficiently injected into the main exhaust system, strengthening the extraction channel. Throughout the process, vacuum is used to reduce the partial pressure of the adsorbate in the gas phase surrounding the adsorbent, thereby driving the adsorbate to desorb from the adsorbent surface. Heating serves as an auxiliary power source, providing the necessary energy to overcome the adsorption barrier and accelerate the desorption process, thus achieving efficient, uniform, and thorough regeneration of the adsorbent at lower temperatures.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A heating device for heat-assisted vacuum desorption, characterized in that, Comprising: A vacuum desorption box (1) with an adsorption bed arranged inside. Support plates (2) are provided at the open ends on both opposite sides of the vacuum desorption box (1), and the adsorption bed is located between the two support plates (2); A PTC heating component, horizontally and vertically inserted into the adsorption bed and distributed in three layers, namely upper, middle and lower, along the height direction of the bed layer for achieving gradient heating or zonal temperature control; Two side flow guiding mechanisms, arranged inside the vacuum desorption box (1); A transmission mechanism, arranged between a plurality of flow guiding shafts (21) distributed in the same layer; A driving mechanism, arranged on the side wall of the vacuum desorption box (1); A drainage structure, used to connect the exhaust pipe (4) and the flow guiding mechanism; Through multiple layers of PTC heating components, a uniform, precise and intrinsically safe main heat field is provided. This heat field can automatically reduce the heating power when the temperature rises. On the basis of this heat field, through two groups of driving motors and corresponding transmission mechanisms, the flow guiding mechanisms at different heights are respectively driven to conduct reverse flow guiding, so as to form tumbling in the adsorption bed layer, thereby synergistically achieving the purposes of eliminating overheating risks, improving desorption safety and simplifying temperature control.

2. The heating device for heat-assisted vacuum desorption according to claim 1, characterized in that, An air inlet pipe (3) is provided at the bottom end of the vacuum desorption box (1) and is communicated therewith, and an exhaust pipe (4) is provided at the top end of the vacuum desorption box (1).

3. The heating device for heat-assisted vacuum desorption according to claim 1, characterized in that, The PTC heating component includes: a plurality of PTC heating rods and a vacuum flange (13). The PTC heating rods are horizontally and vertically inserted into the adsorption bed through the vacuum flange (13). A carbon nanomaterial composite layer is plated on the outer wall of the PTC heating rods. The carbon nanomaterial includes: graphene and carbon nanotubes.

4. The heating device for heat-assisted vacuum desorption according to claim 3, characterized in that, The PTC heating rod includes: a heat conduction pipe (11) and a ceramic element (12), and the ceramic element (12) is sleeved inside the heat conduction pipe (11).

5. A heating device for heat-assisted vacuum desorption according to claim 2, characterized in that, The flow guiding mechanism includes: a plurality of flow guiding shafts (21), rotatably installed between the two support plates (2). The flow guiding shafts (21) are vertically arranged at the center of a rectangular area formed by four PTC heating rods, forming a composite matrix staggered with the PTC heating rod array. A spiral blade (22) is provided on the outer wall of the flow guiding shaft (21). A flow guiding box (23) is provided on the side wall of one of the support plates (2), and the flow guiding box (23) is rotatably connected to the flow guiding shaft (21).

6. The heating device for heat-assisted vacuum desorption according to claim 5, characterized in that, The flow guiding shaft (21) is a hollow shaft tube, with one end open as a medium inlet, and a plurality of flow guiding holes or injection holes communicating with the internal cavity are distributed on the tube wall for converting the axial flow of the medium into radial diffusion.

7. The heating device for heat-assisted vacuum desorption according to claim 5, characterized in that, The flow guiding box (23) is arranged in a "mouth" shape. The open end of the flow guiding shaft (21) is rotatably connected to the flow guiding box (23) through a shaft sleeve. A plurality of sealing shaft sleeves (24) are provided on the side wall of the support plate (2), and the sealing shaft sleeves (24) are rotatably connected to the flow guiding shaft (21).

8. A heating device for heat-assisted vacuum desorption according to claim 5, characterized in that, The transmission mechanism includes: belt wheels (31) and a synchronous belt (32). The belt wheels (31) are provided on the side wall of the flow guiding shaft (21), and the synchronous belt (32) is wound between two adjacent belt wheels (31).

9. A heating device for heat-assisted vacuum desorption according to claim 5, characterized in that, The drive mechanism includes a servo motor (42). Two support frames (41) are provided on the side wall of the support plate (2) near the transmission mechanism. The servo motor (42) is provided on the side wall of the support frame (41). The output shaft of the servo motor (42) is fixedly connected to the shaft end of the guide shaft (21) through a coupling.

10. A heating device for heat-assisted vacuum desorption according to claim 5, characterized in that, The drainage structure includes: a drainage pipe (51), one end of which is connected to the drainage box (23), and the other end is connected to the exhaust pipe (4) through a three-way connector. A first solenoid valve (52) is provided on the side wall of the drainage pipe (51), and a second solenoid valve (53) is provided on the side wall of the exhaust pipe (4).

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