Active carbon nitrogen desorption organic waste gas efficient recovery device

Abstract

The invention provides an activated carbon nitrogen desorption organic waste gas efficient recovery device which comprises an adsorption and desorption tower mechanism, a bottom gas inlet of the adsorption and desorption tower mechanism is connected with a nitrogen rotational flow pulse mechanism, and a top gas outlet of the adsorption and desorption tower mechanism is connected with a cascade heat exchange mechanism. And the outlet end of the cascade heat exchange mechanism and the inlet end of the nitrogen rotational flow pulse mechanism are connected with the nitrogen circulating purification mechanism. The activated carbon bed layer assembly in the adsorption and desorption tower mechanism is matched with the nitrogen distribution assembly, and the nitrogen rotational flow pulse mechanism feeds heated nitrogen in a rotational flow state into the adsorption and desorption tower, so that the contact effect of the nitrogen and the activated carbon bed layer is optimized, and the local'short circuit 'phenomenon is reduced; the step heat exchange mechanism fully recovers waste heat in desorption waste gas, so that energy conservation and consumption reduction are realized; and the nitrogen circulating and purifying mechanism realizes nitrogen circulating and recycling. The whole closed-loop circulation improves the efficiency and stability of VOCs desorption and recovery, and meets the actual requirements of various industrial VOCs treatment scenes.

Description

Technical Field

[0001] This invention relates to the field of waste gas recovery technology, and more specifically, to a high-efficiency recovery device for organic waste gas by activated carbon nitrogen desorption. Background Technology

[0002] Volatile organic compounds (VOCs), as one of the major air pollutants, are widely generated in industries such as coating, printing, chemicals, and pharmaceuticals during industrial production. They not only cause serious damage to the ecological environment but also harm human health. Furthermore, as VOCs are recyclable resources, direct emission of VOCs also leads to energy waste. Currently, activated carbon adsorption-nitrogen desorption recovery technology has become one of the mainstream technologies for industrial VOCs treatment and recovery due to its advantages such as high adsorption efficiency, stable desorption effect, and solvent recycling. It is particularly suitable for treating low-to-medium concentration, high-volume VOCs waste gas, effectively solving the drawbacks of traditional single-use activated carbon adsorption processes, such as rapid saturation, high replacement costs, and high risk of secondary pollution.

[0003] However, existing activated carbon adsorption-nitrogen desorption recovery processes still suffer from numerous efficiency bottlenecks and safety hazards in practical industrial applications, severely hindering their widespread application and optimization: First, uneven contact between the desorbed nitrogen and the activated carbon bed can easily lead to localized "short circuits," causing some activated carbon to fail to fully contact the nitrogen, resulting in low desorption efficiency and incomplete desorption of some adsorbed VOCs. This affects solvent recovery and shortens the activated carbon's lifespan. This imbalance problem mainly stems from unreasonable nitrogen distribution, leading to uneven desorption of the adsorbate during the desorption process, resulting in localized over-desorption and localized over-desorption. The problems include: firstly, incomplete desorption; secondly, the high-concentration organic waste gas generated during the desorption process usually enters the condensation system directly for condensation and recovery, and the large amount of residual heat carried in the waste gas is not effectively recovered and is directly lost, resulting in a large amount of energy consumption in the nitrogen heating process, leading to high overall process energy consumption and high operating costs; and thirdly, uneven temperature distribution in the activated carbon bed, which can easily cause local overheating when nitrogen enters the bed, leading to burn-off and deterioration of the activated carbon and a reduction in its adsorption performance, while local undertemperature can lead to incomplete VOCs desorption, further reducing desorption efficiency and solvent recovery purity. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide an efficient organic waste gas recovery device with activated carbon nitrogen desorption, so as to overcome the defects in the prior art.

[0005] To achieve the above objectives, this invention provides an efficient activated carbon nitrogen desorption organic waste gas recovery device, comprising an adsorption-desorption tower mechanism, a nitrogen cyclone pulse mechanism, a stepped heat exchange mechanism, and a nitrogen circulation and purification mechanism. The nitrogen cyclone pulse mechanism is connected to the bottom inlet of the adsorption-desorption tower mechanism, the stepped heat exchange mechanism is connected to the top outlet of the adsorption-desorption tower mechanism, one end of the nitrogen circulation and purification mechanism is connected to the outlet of the stepped heat exchange mechanism, and the other end of the nitrogen circulation and purification mechanism is connected to the inlet of the nitrogen cyclone pulse mechanism. The adsorption-desorption tower mechanism includes a tower body, an activated carbon bed assembly, and a nitrogen distribution assembly. The activated carbon bed assembly is fixedly installed in the middle of the tower body cavity, and the nitrogen distribution assembly is fixedly installed at the bottom of the tower body cavity and communicates with the bottom inlet. The nitrogen cyclone pulse mechanism includes a cyclone generator, an electric regulating valve, and a nitrogen heater. The outlet of the cyclone generator is connected to the bottom inlet of the adsorption-desorption tower mechanism, and an electric regulating valve is installed on the connecting pipe. The inlet of the cyclone generator is connected to the outlet of the nitrogen heater. The inlet is connected to the adsorption-desorption tower mechanism to deliver heated nitrogen gas into the tower. The cascade heat exchange mechanism includes a primary gas-to-gas heat exchanger, a secondary gas-to-liquid heat exchanger, and a tertiary condenser. The high-temperature inlet of the primary gas-to-gas heat exchanger is connected to the top outlet of the adsorption-desorption tower mechanism, the low-temperature outlet of the primary gas-to-gas heat exchanger is connected to the nitrogen heater inlet of the nitrogen swirl pulse mechanism, the high-temperature outlet of the primary gas-to-gas heat exchanger is connected to the high-temperature inlet of the secondary gas-to-liquid heat exchanger, and the high-temperature outlet of the secondary gas-to-liquid heat exchanger is connected to the tertiary condenser. The inlet end is connected to allow high-temperature desorption waste gas to undergo cascade heat exchange with low-temperature nitrogen to recover waste heat; the nitrogen circulation purification mechanism includes a circulating fan, a deoxygenation catalytic reactor, and a dew point control component; the inlet end of the circulating fan is connected to the outlet end of the three-stage condenser of the cascade heat exchange mechanism, the outlet end of the circulating fan is connected to the inlet end of the deoxygenation catalytic reactor, the outlet end of the deoxygenation catalytic reactor is connected to the dew point control component, and the dew point control component is connected to the inlet of the nitrogen heater of the nitrogen swirl pulse mechanism to realize the reuse of circulating nitrogen after deoxygenation and drying.

[0006] Through the above technical solutions, the nitrogen swirl pulse mechanism can introduce heated nitrogen in a swirling state into the adsorption-desorption tower, effectively improving the contact effect between nitrogen and the activated carbon bed and reducing local "short circuit" phenomena. The cascade heat exchange mechanism, through its multi-stage heat exchange design, can fully recover the waste heat in the desorption exhaust gas for preheating the circulating nitrogen, significantly reducing energy consumption in the nitrogen heating process and achieving energy saving and consumption reduction. The activated carbon bed components and nitrogen distribution components in the adsorption-desorption tower mechanism work together to optimize the bed temperature distribution and nitrogen contact effect, avoiding local overheating or underheating problems. The nitrogen circulation purification mechanism can deoxygenate and dry the circulating nitrogen, effectively removing trace amounts of oxygen accumulated in the circulation system, eliminating the risk of combustion and explosion, and lowering the nitrogen dew point to prevent moisture from affecting the purity of solvent recovery, achieving nitrogen recycling and further reducing operating costs. In addition, the entire closed-loop circulation design reduces nitrogen consumption and exhaust emissions, balancing environmental protection and economy, and improving the overall efficiency and stability of VOCs desorption and recovery, adapting to the actual needs of various industrial VOCs treatment scenarios.

[0007] As a further explanation of the efficient organic waste gas recovery device for activated carbon nitrogen desorption described in this invention, preferably, the nitrogen distribution component includes a distributor base plate, a swirl guide vane, and a flow equalization porous plate; the distributor base plate has multiple air distribution holes arranged in concentric circles, and a swirl guide vane is fixed directly above each air distribution hole. The swirl guide vane forms an angle of 30°-60° with the distributor base plate to transform the nitrogen flow vertically upward from the air distribution hole into a rotating upward nitrogen flow, increasing the contact area between the nitrogen and the activated carbon bed; the flow equalization porous plate is fixed above the swirl guide vane, and the flow equalization porous plate has multiple flow equalization holes to evenly distribute the rotating upward nitrogen flow, ensuring that the evenly distributed nitrogen can uniformly cover the entire activated carbon bed.

[0008] The above technical solution improves the distribution of nitrogen at the bottom of the activated carbon bed by the synergistic effect of the distributor base plate, the swirl guide vanes and the flow equalization porous plate, thus solving the problem of local "short circuit" of nitrogen from the source. The concentrically arranged air distribution holes on the distributor's bottom plate enable initial dispersion of nitrogen, ensuring uniform nitrogen entry into the bottom of the tower. The swirling guide vanes directly above each air distribution hole form a 30°-60° angle with the bottom plate, transforming the vertically upward-spraying nitrogen flow into a rotating, rising nitrogen flow. This significantly increases the contact area and time between nitrogen and the activated carbon bed, enhancing mass and heat transfer and preventing nitrogen from directly passing through the bed and creating a "short circuit." The flow-equalizing porous plate further equalizes the rising nitrogen flow, ensuring uniform nitrogen coverage of the entire activated carbon bed. This allows each part of the activated carbon in the bed to fully contact the nitrogen, achieving uniform and thorough VOCs desorption, significantly improving desorption efficiency. It also ensures uniform bed temperature distribution, reducing localized overheating or underheating, and effectively solving the problem of flow deviation during activated carbon desorption.

[0009] As a further explanation of the high-efficiency organic waste gas recovery device for activated carbon nitrogen desorption described in this invention, preferably, the diameter of the air distribution holes on the bottom plate of the distributor is 5-15 mm, and the opening rate is 15%-25%; the diameter of the flow equalization holes on the flow equalization porous plate is 2-5 mm, and the opening rate is 40%-60%; the flow equalization porous plate is 100-200 mm away from the lower surface of the activated carbon bed assembly.

[0010] Through the above technical solution, the pore size of the gas distribution holes on the distributor base plate is set to 5-15mm, and the opening rate is 15%-25%. This ensures sufficient nitrogen flow, avoids excessive airflow resistance, and achieves initial uniform dispersion of nitrogen, providing a good foundation for swirling guidance. The pore size of the flow equalization porous plate is set to 2-5mm, and the opening rate is 40%-60%. This effectively equalizes the rising nitrogen flow, refines the airflow, and ensures that nitrogen penetrates evenly into every area of ​​the activated carbon bed. At the same time, it avoids the problems of poor flow equalization due to excessively high opening rate and excessive airflow resistance due to excessively low opening rate. The flow equalization porous plate is 100-200mm away from the lower surface of the activated carbon bed assembly, providing sufficient buffer space for the rising nitrogen flow. This allows the airflow to be fully mixed and evenly distributed before entering the activated carbon bed, further improving contact uniformity and avoiding localized airflow concentration caused by direct airflow impact on the bed. This ensures a stable increase in desorption efficiency while protecting the activated carbon bed structure and reducing bed loosening caused by airflow impact.

[0011] As a further explanation of the high-efficiency organic waste gas recovery device for activated carbon nitrogen desorption described in this invention, preferably, the activated carbon bed assembly includes an upper activated carbon bed and a lower activated carbon bed; a nitrogen redistribution chamber is provided between the upper and lower activated carbon beds; the nitrogen redistribution chamber includes an annular gas collection chamber, a conical diffuser hood, and a rectifying grid; the large end of the conical diffuser hood faces upward and is close to the lower surface of the upper activated carbon bed, and the small end of the conical diffuser hood is connected to the annular gas collection chamber; the surface of the conical diffuser hood is provided with multiple diffusion holes, and the diameter of the multiple diffusion holes gradually increases from the small end to the large end; a tangential air inlet is provided on the side wall of the annular gas collection chamber, and the tangential air inlet is connected to the supplementary nitrogen pipe on the side wall of the tower body; the rectifying grid is composed of multiple layers of staggered horizontal bars, and the rectifying grid is positioned above the conical diffuser hood so that nitrogen enters the upper activated carbon bed vertically.

[0012] Through the above technical solutions, the double-layer activated carbon bed design can extend the contact path between nitrogen and activated carbon, enabling VOCs to be desorbed in stages and gradually, avoiding the problem of incomplete desorption caused by the gradual increase of VOCs concentration in nitrogen in a single-layer bed. The annular gas collection chamber of the nitrogen redistribution chamber can introduce supplementary nitrogen through the tangential air inlet to compensate for the concentration loss and temperature drop of circulating nitrogen during the desorption process in the lower bed. At the same time, the diffusion holes on the surface of the conical diffuser, with the aperture gradually increasing from the small end to the large end, can ensure that the supplementary nitrogen and the circulating nitrogen passing through the lower bed are fully mixed and uniformly diffused to the upper activated carbon bed, avoiding the problem of insufficient nitrogen concentration and excessively low temperature in the upper bed. The rectifier grid can transform the diffused nitrogen flow into a vertically upward airflow, ensuring that the nitrogen enters the upper activated carbon bed vertically, further optimizing the contact uniformity, while suppressing local airflow turbulence in the bed, avoiding uneven temperature distribution, and effectively preventing local burn-out of activated carbon or incomplete desorption.

[0013] As a further explanation of the activated carbon nitrogen desorption organic waste gas high-efficiency recovery device of the present invention, preferably, the diameter of the diffusion hole at the small end of the conical diffusion hood is 3-5mm, and the diameter of the diffusion hole at the large end is 8-12mm; the horizontal spacing between the center lines of two adjacent horizontal grid bars in each layer of the rectifier grid is 10-20mm, and the thickness of a single horizontal grid bar is 20-30mm.

[0014] Through the above technical solution, the aperture of the small-mouth diffusion hole of the conical diffuser is set to 3-5mm and the large-mouth hole is set to 8-12mm, which is adapted to the flow pattern of nitrogen in the diffuser. The smaller aperture at the small end ensures that the nitrogen has a sufficient flow velocity to achieve rapid diffusion, while the larger aperture at the large end allows the nitrogen to uniformly cover the entire cross-section of the upper bed, avoiding local nitrogen concentration and ensuring that every part of the upper bed receives sufficient nitrogen. The center-line spacing between adjacent horizontal bars in each layer of the rectifying grid is 10-20mm, and the thickness of a single bar is 20-30mm. This can effectively rectify the diffused nitrogen flow, transforming the rotating or turbulent airflow into a stable vertical airflow. At the same time, it avoids the problems of poor rectification effect due to excessively large bar spacing and excessive airflow resistance due to excessively small spacing. The bar thickness design can enhance the stability of the grid structure, extend its service life, and ensure that the nitrogen enters the upper activated carbon bed vertically and uniformly, further optimizing the bed temperature distribution and nitrogen contact effect, and ensuring the stability and thoroughness of the desorption process.

[0015] As a further explanation of the activated carbon nitrogen desorption organic waste gas high-efficiency recovery device of the present invention, preferably, the cyclone generator includes a tangential air inlet pipe, a guide cone, and a cyclone intensity adjusting blade; the tangential air inlet pipe is fixedly welded to the tangential direction of the cyclone generator, and the cyclone intensity adjusting blade is rotatably disposed in the tangential air inlet pipe to change the tangential velocity component of the nitrogen entering; the guide cone is fixedly disposed at the central axis position of the cyclone generator to guide the nitrogen to form a stable cyclone field.

[0016] Through the above technical solution, the tangential inlet pipe is fixedly welded to the tangential direction of the cyclone generator, allowing nitrogen to enter the generator tangentially, providing a basis for the formation of the cyclone field. The cyclone intensity adjustment blade is rotatably installed inside the tangential inlet pipe, allowing flexible adjustment of the tangential velocity component of the nitrogen entering according to the desorption conditions (such as VOCs concentration and activated carbon bed condition), thereby adjusting the cyclone intensity to adapt to different desorption requirements. When the VOCs concentration is high, the cyclone intensity can be increased to enhance the mass transfer effect; when the bed resistance is high, it can be appropriately reduced. The swirling intensity is increased, reducing energy consumption. The guide cone is fixedly positioned at the central axis of the swirling generator to guide the nitrogen flow entering the generator, avoiding airflow turbulence and ensuring the formation of a stable and uniform swirling field. This prevents local nitrogen concentration or "short circuit" caused by swirling deviation, allowing the heated nitrogen to enter the adsorption-desorption tower in a stable swirling state, further increasing the contact area with the activated carbon bed and improving desorption efficiency. It also helps to achieve a uniform temperature distribution in the bed and effectively improves the flow deviation problem in activated carbon desorption by enhancing airflow disturbance.

[0017] As a further explanation of the activated carbon nitrogen desorption organic waste gas high-efficiency recovery device of the present invention, preferably, the primary gas-to-gas heat exchanger includes a plate heat exchange core and a thermal bypass regulating valve; wherein, the plate heat exchange core is composed of multiple corrugated plates stacked together, with adjacent corrugated plates having opposite corrugation directions to form a mesh flow channel and forming alternating high-temperature waste gas channels and low-temperature nitrogen channels; the inlet of the high-temperature waste gas channel is connected to the top outlet of the adsorption-desorption tower mechanism, and the outlet of the high-temperature waste gas channel is connected to the high-temperature side inlet of the secondary gas-liquid heat exchanger; the outlet of the low-temperature nitrogen channel is connected to the inlet of the nitrogen heater of the nitrogen swirl pulse mechanism; the thermal bypass regulating valve is an electric three-way regulating valve, the inlet of the thermal bypass regulating valve is connected to the low-temperature nitrogen source, the first outlet is connected to the inlet of the low-temperature nitrogen channel, and the second outlet is connected to the connecting pipe between the outlet of the low-temperature nitrogen channel and the inlet of the nitrogen heater through a bypass pipe, so as to adjust the proportion of bypass nitrogen according to the nitrogen temperature.

[0018] Through the above technical solution, the plate heat exchanger core is composed of multiple corrugated plates stacked together, with adjacent corrugated plates having opposite corrugation directions, forming a mesh-like flow channel. Simultaneously, it forms alternating high-temperature exhaust gas channels and low-temperature nitrogen channels. This structural design significantly increases the heat exchange area, enhances turbulence, and disrupts the laminar boundary layer on the fluid surface, allowing for sufficient heat exchange between the high-temperature desorbed exhaust gas and the low-temperature nitrogen. This significantly improves waste heat recovery efficiency. Compared to traditional heat exchangers, it can achieve higher heat transfer efficiency at low flow rates, with a heat transfer coefficient 2-3 times that of traditional shell-and-tube heat exchangers. The heat bypass regulating valve adopts... The electric three-way regulating valve allows for flexible adjustment of the bypass nitrogen ratio based on the nitrogen temperature. When the nitrogen temperature is too high after waste heat recovery, the bypass nitrogen ratio can be increased to lower the nitrogen temperature entering the nitrogen heater, preventing localized overheating of the activated carbon bed. Conversely, when the nitrogen temperature is too low after waste heat recovery, the bypass nitrogen ratio can be decreased to ensure that the nitrogen temperature entering the heater meets the desorption requirements. This precise control of the nitrogen temperature not only fully recovers the waste heat from the desorption waste gas and reduces energy consumption in the nitrogen heating process, but also avoids uneven activated carbon bed temperature, improving process stability and energy efficiency.

[0019] As a further explanation of the high-efficiency recovery device for activated carbon nitrogen desorption of organic waste gas described in this invention, preferably, the secondary gas-liquid heat exchanger includes a spiral coil, a phase change heat storage material filling layer, and an automatic exhaust valve; the spiral coil is fixed inside the shell of the secondary gas-liquid heat exchanger for circulating desorbed waste gas; the phase change heat storage material filling layer is filled between the spiral coil and the shell; a temperature sensor is embedded in the phase change heat storage material filling layer for monitoring the phase change state; the automatic exhaust valve is a float-type exhaust valve, which is located at the highest point of the spiral coil for discharging non-condensable gases and preventing gas blockage.

[0020] Through the above technical solution, the spiral coil is fixed inside the shell for the circulation of desorbed waste gas. The spiral structure increases the residence time of the waste gas in the heat exchanger, improving heat exchange efficiency, and facilitating installation and maintenance. The phase change heat storage material filling layer is filled between the spiral coil and the shell, which can store the waste heat in the desorbed waste gas. When the waste gas temperature fluctuates, the phase change heat storage material can release or absorb heat to ensure stable heat exchange temperature and avoid poor subsequent condensation effect caused by waste gas temperature fluctuation. At the same time, it can further recover waste heat and improve energy utilization. The temperature sensor embedded in the phase change heat storage material filling layer can monitor the phase change state in real time, allowing operators to adjust the operating conditions in a timely manner and ensure the stability of the heat storage and release process. The float-type automatic exhaust valve is set at the highest point of the spiral coil, which can automatically discharge the non-condensable gases generated during the heat exchange process, effectively preventing gas resistance and avoiding problems such as reduced heat exchange efficiency and poor fluid flow caused by gas resistance. This ensures the continuous and stable operation of the secondary heat exchange process and provides good conditions for subsequent waste gas condensation and recovery.

[0021] As a further explanation of the activated carbon nitrogen desorption organic waste gas high-efficiency recovery device of the present invention, preferably, the dew point control component includes a molecular sieve adsorption tower, an electrically heated regeneration pipeline, and a gas-liquid separator; two molecular sieve adsorption towers are provided, both of which are vertical cylindrical, with a wire mesh demister at the top and a supporting grid and ceramic ball support layer at the bottom; the two molecular sieve adsorption towers are connected to the outlet end of the deoxygenation catalytic reactor through a first switching valve to achieve alternating operation and regeneration; the electrically heated regeneration pipeline includes an electric heater and a regeneration nitrogen pipeline; the inlet of the regeneration nitrogen pipeline is connected to the circulating nitrogen main pipe, and the outlet of the regeneration nitrogen pipeline is connected to the top regeneration inlet of the two molecular sieve adsorption towers through the electric heater and a second switching valve; the bottom regeneration outlet of the two molecular sieve adsorption towers is connected to the inlet end of the gas-liquid separator through a third switching valve, and the outlet end of the gas-liquid separator is connected to the nitrogen heater inlet of the nitrogen swirl pulse mechanism to achieve countercurrent heating regeneration.

[0022] Through the above technical solution, two vertical cylindrical molecular sieve adsorption towers alternately operate and regenerate by switching valves, adopting a cyclic working mode similar to pressure swing adsorption. This ensures continuous nitrogen purification, avoids interruption of nitrogen circulation due to molecular sieve regeneration, and improves the overall operational stability of the device. The molecular sieve can effectively adsorb moisture in nitrogen, lowering the nitrogen dew point. Simultaneously, in conjunction with the deoxygenation catalytic reactor, it can completely remove trace amounts of oxygen from the circulating nitrogen. The wire mesh demister at the top of the molecular sieve adsorption tower removes droplets from the nitrogen, preventing them from entering the molecular sieve and affecting the adsorption effect. The support grid and ceramic ball support layer at the bottom effectively support the molecular sieve, preventing its loss and ensuring uniform nitrogen flow through the molecular sieve bed, thus improving adsorption efficiency. The electrically heated regeneration pipeline connected between the two molecular sieve adsorption towers allows for the electrically heated regeneration of saturated molecular sieves, restoring their adsorption performance and enabling molecular sieve recycling, thereby reducing operating costs.

[0023] The beneficial effects of this invention are as follows: The invention utilizes a nitrogen swirl pulse mechanism to introduce heated nitrogen in a swirling state into the adsorption-desorption tower, effectively improving the contact between nitrogen and the activated carbon bed and reducing localized "short circuits." The cascade heat exchange mechanism, through its multi-stage heat exchange design, can fully recover the waste heat from the desorption exhaust gas for preheating the circulating nitrogen, significantly reducing energy consumption in the nitrogen heating process and achieving energy saving. The activated carbon bed components and nitrogen distribution components within the adsorption-desorption tower mechanism work together to optimize the bed temperature distribution and nitrogen contact effect, avoiding localized overheating or underheating. The nitrogen circulation purification mechanism can deoxygenate and dry the circulating nitrogen, effectively removing trace amounts of oxygen accumulated in the circulation system, eliminating the risk of combustion and explosion, and lowering the nitrogen dew point to prevent moisture from affecting the purity of solvent recovery, achieving nitrogen recycling and further reducing operating costs. Furthermore, the entire closed-loop design reduces nitrogen consumption and exhaust emissions, balancing environmental protection and economy, and comprehensively improving the efficiency and stability of VOCs desorption and recovery, adapting to the actual needs of various industrial VOCs treatment scenarios. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the activated carbon nitrogen desorption organic waste gas high-efficiency recovery device of the present invention; Figure 2 This is a schematic diagram of the adsorption-desorption tower mechanism of the present invention; Figure 3 This is a schematic diagram of the nitrogen swirling pulse mechanism of the present invention; Figure 4 This is a schematic diagram of the cascade heat exchange mechanism of the present invention; Figure 5 This is a schematic diagram of the nitrogen circulation purification mechanism of the present invention. Detailed Implementation

[0025] To further understand the structure, features, and other objectives of the present invention, a detailed description is provided below with reference to the accompanying drawings. The embodiments illustrated in these drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] This embodiment provides a high-efficiency organic waste gas recovery device using activated carbon nitrogen desorption, such as... Figure 1 As shown, it includes an adsorption-desorption tower mechanism 1, a nitrogen cyclone pulse mechanism 2, a stepped heat exchange mechanism 3, and a nitrogen circulation purification mechanism 4. The nitrogen cyclone pulse mechanism 2 is connected to the bottom inlet of the adsorption-desorption tower mechanism 1, the stepped heat exchange mechanism 3 is connected to the top outlet of the adsorption-desorption tower mechanism 1, one end of the nitrogen circulation purification mechanism 4 is connected to the outlet of the stepped heat exchange mechanism 3, and the other end of the nitrogen circulation purification mechanism 4 is connected to the inlet of the nitrogen cyclone pulse mechanism 2.

[0027] like Figure 2As shown, in this embodiment, the adsorption-desorption tower mechanism 1 mainly includes a tower body 11, an activated carbon bed assembly 12, and a nitrogen distribution assembly 13. The activated carbon bed assembly 12 is fixedly installed in the middle of the inner cavity of the tower body 11, and the nitrogen distribution assembly 13 is fixedly installed at the bottom of the inner cavity of the tower body 11 and connected to the bottom air inlet. The tower body 11 adopts a vertical cylindrical structure, is made of 304 stainless steel, and has an air outlet at the top and an air inlet at the bottom.

[0028] In some embodiments, such as Figure 2 As shown, the nitrogen distribution assembly 13 specifically includes a distributor base plate 131, swirl guide vanes 132, and a flow equalization perforated plate 133. The distributor base plate 131 is a circular steel plate with a diameter matching the inner diameter of the tower body, and has multiple air distribution holes arranged concentrically on it. The aperture of the air distribution holes is preferably 5-15mm, and the opening ratio is preferably 15%-25% to ensure sufficient nitrogen flow and initial dispersion. A swirl guide vane 132 is welded and fixed directly above each air distribution hole. The vane is made of 304 stainless steel and can form an angle of 30°-60° with the distributor base plate 131. This angle can maximize the transformation of the nitrogen flow vertically upward from the air distribution hole into a rotating upward nitrogen flow, which increases the contact area between nitrogen and the activated carbon bed, avoids excessive airflow resistance, and thus enhances mass and heat transfer and reduces local short circuits. The flow equalization perforated plate 133 is fixed above the swirl guide vane 132. A flanged structure is integrally formed around the outer circumference of the flow equalization perforated plate 133. This flanged structure is engaged with a pre-set step on the inner wall of the tower body 11 to fix the flow equalization perforated plate 133 within the tower body 11 and ensure the sealing of the flow equalization perforated plate 133 after assembly, preventing nitrogen leakage from the gap between the plate and the tower wall. The flow equalization perforated plate 133 is fixed below the activated carbon bed assembly 12, preferably at a distance of 100-200 mm from the lower surface of the activated carbon bed assembly 12. The flow equalization porous plate 133 has multiple flow equalization holes, with a preferred pore size of 2-5 mm and a preferred porosity of 40%-60%. This allows for further equalization and refinement of the rotating and rising nitrogen flow, ensuring that nitrogen uniformly covers the entire lower activated carbon bed 122, avoiding localized airflow concentration, and providing a buffer space for the nitrogen flow to reduce the impact of the airflow on the bed, protect the activated carbon bed structure, and thus optimize nitrogen distribution and stabilize desorption efficiency.

[0029] In some embodiments, such as Figure 2As shown, the activated carbon bed assembly 12 preferably adopts a double-layer structure, consisting of an upper activated carbon bed 121 and a lower activated carbon bed 122. Both beds use a grid-type support structure, with the grid material being 316L stainless steel. The upper activated carbon bed 121 is filled with honeycomb activated carbon with a particle size of 3-5mm, mainly used for secondary desorption of low-concentration VOCs after desorption from the lower layer, ensuring thorough desorption. The lower activated carbon bed 122 is filled with granular activated carbon with a particle size of 2-4mm, mainly used for initial desorption. Utilizing the large specific surface area of ​​the granular activated carbon, it rapidly adsorbs and desorbs high-concentration VOCs. The filling height of the two beds can be adjusted according to actual needs.

[0030] To achieve secondary uniform distribution of nitrogen and solve the problems of incomplete desorption and uneven temperature distribution in a single-layer activated carbon bed, a nitrogen redistribution chamber 14 can be provided between the upper activated carbon bed 121 and the lower activated carbon bed 122, such as... Figure 2 As shown. The nitrogen redistribution chamber 14 includes an annular gas collecting chamber 141, a conical diffuser 142, and a rectifier grid 143. The annular gas collecting chamber 141 is an annular steel pipe with a tangential inlet on its wall, connected to a supplementary nitrogen pipe on the side wall of the tower body 11, allowing supplementary nitrogen to be introduced to compensate for the loss of circulating nitrogen and temperature drop. The larger end of the conical diffuser 142 faces upward and is close to the lower surface of the upper activated carbon bed 121, while the smaller end of the conical diffuser 142 communicates with the annular gas collecting chamber 141. Multiple diffusion holes are formed on the surface of the conical diffuser 142, with the hole diameter gradually increasing from the smaller end to the larger end. Preferably, the diameter of the diffusion holes at the smaller end is 3-5 mm, and the diameter of the diffusion holes at the larger end is 8-12 mm. This gradual diameter design adapts to the nitrogen diffusion pattern, ensuring uniform diffusion of nitrogen to the upper activated carbon bed 121. The rectifying grid 143 consists of multiple layers of staggered horizontal grid bars, preferably three layers, and is positioned above the conical diffuser 142 to allow nitrogen gas to enter the upper activated carbon bed 121 vertically. The grid bars are made of 304 stainless steel, with a horizontal spacing of 10-20 mm between the center lines of two adjacent horizontal grid bars in each layer, and a thickness of 20-30 mm for each horizontal grid bar. This rectifyes the turbulent airflow after diffusion into a vertically upward airflow, ensuring that nitrogen gas enters the upper activated carbon bed 121 vertically, further optimizing contact uniformity, avoiding uneven temperature distribution in the bed, and preventing localized burn-off of the activated carbon.

[0031] As nitrogen passes through the lower bed, the VOCs concentration increases and the temperature decreases. The nitrogen redistribution chamber 14 introduces supplementary nitrogen for mixing and uniform distribution, so that the upper bed obtains nitrogen with uniform concentration and temperature. This avoids incomplete desorption or excessively low temperature in some parts of the upper bed. At the same time, the double bed extends the contact path between nitrogen and activated carbon, enabling VOCs to be desorbed in stages and improving desorption efficiency.

[0032] like Figure 1As shown, in this embodiment, the nitrogen swirling pulse mechanism 2 mainly includes a swirling generator 21, an electric regulating valve 22, and a nitrogen heater 23. These three components are connected in series via a sealed pipeline and arranged on one side of the bottom of the adsorption-desorption tower mechanism 1. The outlet end of the swirling generator 21 is connected to the bottom air inlet of the adsorption-desorption tower mechanism 1, and the electric regulating valve 22 is installed on the connecting pipeline. The inlet end of the swirling generator 21 is connected to the outlet end of the nitrogen heater 23, used to send heated nitrogen into the adsorption-desorption tower mechanism 1. The electric regulating valve 22 and the nitrogen heater 23 are both existing products; for example, the ZAZ type electric regulating valve from Zhejiang Niwei Fluid Control Co., Ltd., and the nitrogen pipeline heater from Jiangsu Zhongre Machinery Equipment Co., Ltd., can be used.

[0033] In some embodiments, such as Figure 3 As shown, the swirl generator 21 includes a tangential inlet pipe 211, a guide cone 212, and swirl intensity adjusting blades 213. The tangential inlet pipe 211 is fixedly welded to the tangential direction of the swirl generator 21, allowing nitrogen to enter the generator cavity tangentially, providing a basis for the formation of the swirl field. The swirl intensity adjusting blades 213 are rotatably disposed inside the tangential inlet pipe 211 to change the tangential velocity component of the nitrogen entering the generator. The blade angle can be adjusted between 0-30° and the rotation is controlled by an electric actuator. The tangential velocity component of the nitrogen can be flexibly adjusted according to operating conditions such as VOCs concentration and bed resistance. For example, when the VOCs concentration is high, the blade angle can be adjusted to 25° to increase the swirl intensity and enhance the mass transfer effect between nitrogen and activated carbon. When the bed resistance is high, the blade angle can be adjusted to 10° to reduce the swirl intensity and reduce energy consumption. The guide cone 212 is fixedly installed at the central axis of the swirling generator 21 to guide nitrogen to form a stable swirling field and prevent local nitrogen concentration or "short circuit" caused by swirling deviation.

[0034] like Figure 1 As shown, in this embodiment, the cascade heat exchange mechanism 3 includes a primary gas-to-gas heat exchanger 31, a secondary gas-to-liquid heat exchanger 32, and a tertiary condenser 33. These three components are connected in series via sealed pipes and arranged on one side of the top of the adsorption-desorption tower mechanism 1, connected to the top outlet of the adsorption-desorption tower to form a waste heat recovery link. Specifically, the high-temperature inlet of the primary gas-to-gas heat exchanger 31 is connected to the top outlet of the adsorption-desorption tower mechanism 1; the low-temperature outlet of the primary gas-to-gas heat exchanger 31 is connected to the inlet of the nitrogen heater 23 of the nitrogen swirl pulse mechanism 2; the high-temperature outlet of the primary gas-to-gas heat exchanger 31 is connected to the high-temperature inlet of the secondary gas-to-liquid heat exchanger 32; and the high-temperature outlet of the secondary gas-to-liquid heat exchanger 32 is connected to the inlet of the tertiary condenser 33, enabling cascade heat exchange between the high-temperature desorbed waste gas and the low-temperature nitrogen to recover waste heat.

[0035] In some embodiments, such as Figure 4As shown, the primary gas-to-gas heat exchanger 31 includes a plate heat exchange core 311 and a heat bypass regulating valve 312. The plate heat exchange core 311 is composed of multiple corrugated plates 311a stacked together. The corrugated plates 311a are made of 304 austenitic stainless steel, which can balance heat transfer efficiency, corrosion resistance, and economy. The corrugations of adjacent corrugated plates 311a are opposite in direction, forming a mesh flow channel, and simultaneously forming alternating high-temperature exhaust gas channels 311b and low-temperature nitrogen channels 311c. This structural design can significantly increase the heat exchange area (up to 200㎡), enhance the turbulence effect, and destroy the laminar boundary layer on the fluid surface, so that the high-temperature desorbed exhaust gas and low-temperature nitrogen can fully exchange heat. The waste heat recovery efficiency can reach more than 75%, and the heat transfer coefficient is about 2.5 times that of traditional shell-and-tube heat exchangers. The inlet of the high-temperature waste gas channel 311b is located on the lower side of the primary gas-to-gas heat exchanger 31, and is directly connected to the top outlet of the adsorption-desorption tower mechanism 1 via a DN200 corrosion-resistant sealed pipe. A flanged connection is installed on the pipe to ensure a tight seal and prevent leakage of the high-temperature waste gas. The outlet is located on the upper side of the primary gas-to-gas heat exchanger 31, and is connected to the high-temperature side inlet of the secondary gas-liquid heat exchanger 32 via a DN200 pipe, forming a waste gas flow path. The high-temperature desorption waste gas (approximately 110℃) from the adsorption-desorption tower enters the high-temperature waste gas channel 311b through the lower inlet, flows along the mesh flow channel, and undergoes sufficient heat exchange with the nitrogen in the adjacent low-temperature nitrogen channel 311c. After releasing residual heat, the temperature drops to approximately 60℃, and then it is discharged through the upper outlet, entering the secondary gas-liquid heat exchanger for further treatment. The staggered arrangement of the inlet and outlet extends the residence time of the waste gas in the channel, ensuring sufficient release of residual heat. The plate heat exchanger core 311 is connected by a pipe, and air holes are opened in each high-temperature exhaust gas channel 311b so that the high-temperature exhaust gas flows only in the high-temperature exhaust gas channel 311b.

[0036] The heat bypass regulating valve 312 is an electric three-way regulating valve (such as the three-way regulating valve from Shanghai Wilton Valve Co., Ltd.). Its inlet is connected to a cryogenic nitrogen source, its first outlet is connected to the inlet of the cryogenic nitrogen channel 311c, and its second outlet is connected via a bypass pipe to the connecting pipe between the outlet of the cryogenic nitrogen channel 311c and the inlet of the nitrogen heater 23. It can automatically adjust the bypass nitrogen ratio based on the nitrogen temperature signal fed back by the temperature sensor. For example, when the nitrogen temperature reaches 100℃ after waste heat recovery (close to the desorption set temperature of 120℃), the bypass nitrogen ratio is increased, allowing some cryogenic nitrogen to directly enter the nitrogen heater, thus avoiding excessive nitrogen temperature leading to local overheating of the bed. When the nitrogen temperature is only 60℃ after waste heat recovery, the bypass nitrogen ratio is decreased, allowing all the nitrogen to enter the cryogenic nitrogen channel for continued heat exchange, ensuring a stable nitrogen temperature entering the nitrogen heater and reducing heater energy consumption.

[0037] The inlet of the low-temperature nitrogen channel 311c is located on the upper side of the primary gas-to-gas heat exchanger 31 (on the same side as the outlet of the high-temperature waste gas channel, at the same height); the outlet is located on the lower side of the primary gas-to-gas heat exchanger 31 (on the same side as the inlet of the high-temperature waste gas channel, at the same height). The purified low-temperature nitrogen (approximately 40°C) enters the low-temperature nitrogen channel 311c from the upper inlet and flows from top to bottom along the mesh flow channel (in the opposite direction to the high-temperature waste gas), fully absorbing the residual heat transferred by the high-temperature waste gas channel 311b. After the temperature rises to about 85°C, it is discharged from the lower outlet. The flow ratio is then adjusted by the heat bypass regulating valve 312 to adapt to the nitrogen heating requirements.

[0038] In some embodiments, such as Figure 4 As shown, the secondary gas-liquid heat exchanger 32 includes a spiral coil 321, a phase change heat storage material filling layer 322, and an automatic exhaust valve 323. The secondary gas-liquid heat exchanger 32 is a shell-and-tube heat exchanger with a shell made of 304 stainless steel. The spiral coil 321 is fixedly installed inside the shell for circulating the desorbed waste gas. The spiral coil is preferably a DN50 stainless steel tube with 15 turns. The spiral structure increases the residence time of the waste gas in the heat exchanger, improving heat exchange efficiency, and also facilitates installation and maintenance. The phase change heat storage material filling layer 322 fills the space between the spiral coil 321 and the shell. The phase change heat storage material can be a paraffin-based phase change material with a phase change temperature of 55℃. It can absorb or release heat when the exhaust gas temperature fluctuates, ensuring stable heat exchange temperature. For example, when the exhaust gas temperature rises to 65℃, the phase change material absorbs heat and melts; when the exhaust gas temperature drops to 50℃, the phase change material releases heat and solidifies, avoiding poor subsequent condensation due to exhaust gas temperature fluctuations, while further recovering waste heat. A temperature sensor 322a is embedded in the phase change heat storage material filling layer 322 to monitor the phase change state. The automatic exhaust valve 323 is a float-type exhaust valve (such as the AEV-B12P DN20 stainless steel high-temperature exhaust valve from Shanghai Shigao Valve Co., Ltd.). The automatic exhaust valve 323 is located at the highest point of the spiral coil 321 to discharge non-condensable gases, preventing air blockage and avoiding problems such as decreased heat exchange efficiency and poor fluid flow caused by air blockage.

[0039] In this embodiment, the tertiary condenser 33 is a shell-and-tube condenser from the prior art (such as standard water-cooled shell-and-tube condenser products produced by manufacturers such as Jinan Kude Refrigeration Equipment Co., Ltd., Nanjing Jindian Refrigeration Industry Co., Ltd., and Jiangsu Sunrise Machinery Co., Ltd.). The cooling medium is industrial cooling water (temperature 25°C). It is connected to the outlet of the secondary gas-liquid heat exchanger 32. The exhaust gas (temperature about 55°C) after the secondary heat exchange enters the condenser. Under the cooling effect of the cooling water, the VOCs in the exhaust gas condense into liquid solvent, realizing solvent recovery. The condensed solvent enters the solvent storage tank through the bottom outlet. The remaining nitrogen (containing a small amount of uncondensed VOCs, trace amounts of oxygen and moisture) is discharged from the top outlet and enters the nitrogen circulation purification mechanism 4.

[0040] like Figure 1 As shown, in this embodiment, the nitrogen circulation purification mechanism 4 adopts a modular design. Its function is realized through a combination of mature unit equipment known in the art, specifically including a circulating fan 41, an oxygen removal catalytic reactor 42, and a dew point control component 43. The three are connected in series through a sealed pipeline to form a closed loop for nitrogen purification. The inlet end of the circulating fan 41 is connected to the outlet end of the three-stage condenser 33 of the stepped heat exchange mechanism 3. The outlet end of the circulating fan 41 is connected to the inlet end of the oxygen removal catalytic reactor 42. The outlet end of the oxygen removal catalytic reactor 42 is connected to the dew point control component 43. The dew point control component 43 is connected to the inlet of the nitrogen heater 23 of the nitrogen swirl pulse mechanism 2 to achieve the reuse of the deoxygenated and dried circulating nitrogen. This is used to deoxygenate and dry the circulating nitrogen, eliminate the risk of combustion and explosion, and improve the purity of solvent recovery. The circulating fan 41 is a centrifugal fan with an air volume of 1500 m³ / h and an air pressure of 50 kPa, providing power for nitrogen circulation and ensuring stable flow of nitrogen within the closed-loop system. The deoxygenation catalytic reactor 42 is a fixed-bed reactor. Its core feature is that the reactor is filled with a palladium-based catalyst (purchased from Dalian Shengmei Chemical New Technology Co., Ltd.). The catalyst support is alumina. It can catalytically oxidize trace amounts of oxygen (concentration ≤500ppm) in nitrogen to water at room temperature, completely removing oxygen from nitrogen and eliminating the risk of combustion and explosion. An oxygen concentration sensor is installed at the reactor outlet to monitor the oxygen concentration in nitrogen in real time and ensure that the oxygen concentration is ≤300ppm (safe threshold). To obtain a matching catalyst model and reactor, the operating parameters can be specified from the supplier for customization.

[0041] In some embodiments, such as Figure 5As shown, the dew point control component 43 includes a molecular sieve adsorption tower 431, an electrically heated regeneration pipeline 432, and a gas-liquid separator 433. Two vertical cylindrical molecular sieve adsorption towers 431 are installed. The interior of each tower is filled with 13X type zeolite molecular sieve (purchased from Henan Sanyi Water Treatment Technology Co., Ltd.). The 13X type zeolite molecular sieve has extremely strong water absorption performance, effectively adsorbing moisture in nitrogen and lowering the nitrogen dew point to below -40℃, ensuring the nitrogen is dry. A wire mesh demister 431a (100 mesh; custom mesh sizes and installation dimensions can be obtained from wire mesh component manufacturers, such as the wire mesh demisters from Jiangxi Pingxiang Dier Chemical Packing Co., Ltd.) is installed at the top to remove liquid droplets from the nitrogen, preventing them from entering the molecular sieve and affecting the adsorption effect. A supporting grid 431b and a ceramic ball support layer 431c are installed at the bottom. The ceramic balls have a particle size of 10-15mm and a filling height of 0.3m, effectively supporting the molecular sieve and preventing its loss. Two molecular sieve adsorption towers 431 are connected to the outlet of the deoxygenation catalytic reactor 42 via a first switching valve 431d, enabling alternating operation and regeneration. This cyclical operation, similar to pressure swing adsorption, ensures continuous nitrogen purification and prevents interruption of nitrogen circulation due to molecular sieve regeneration. The electrically heated regeneration pipeline 432 includes an electric heater 432a and a regeneration nitrogen pipeline 432b. The inlet of the regeneration nitrogen pipeline 432b is connected to the main circulating nitrogen pipe, and the outlet of the regeneration nitrogen pipeline 432b is connected to the top regeneration inlet of each of the two molecular sieve adsorption towers 431 via the electric heater 432a and a second switching valve 431e. A portion of the purified dry nitrogen can be introduced into the electric heater for regeneration of the saturated molecular sieve. Moisture-containing gases generated during regeneration are discharged to the waste gas treatment device via the regeneration nitrogen pipeline. The regenerated molecular sieves regain their adsorption performance and are ready for the next switching operation. The bottom regeneration outlets of the two molecular sieve adsorption towers 431 are connected to the inlet of the gas-liquid separator 433 via a third switching valve 431f. The outlet of the gas-liquid separator 433 is connected to the inlet of the nitrogen heater 23 of the nitrogen cyclone pulse mechanism 2 to achieve countercurrent heating regeneration. The gas-liquid separator 433 can be an MQF-cyclone gas-water separator, such as that from Xinxiang Mait Filtration Equipment Co., Ltd.

[0042] The working process of the activated carbon nitrogen desorption organic waste gas high-efficiency recovery device in this embodiment revolves around four core links: nitrogen closed-loop circulation, VOCs desorption, waste heat recovery, and nitrogen purification. These mechanisms work together to achieve efficient VOCs desorption and recovery. The specific working process is as follows: At the initial startup stage, the organic waste gas (VOCs) to be treated is introduced into the tower body 11 of the adsorption-desorption tower mechanism 1. The waste gas flows upward through the nitrogen distribution component 13 and the activated carbon bed assembly 12. The upper activated carbon bed 121 and the lower activated carbon bed 122 of the activated carbon bed assembly 12 perform stratified adsorption and deep enrichment of the organic components in the waste gas. After adsorption, the clean gas is discharged through the top outlet of the tower body 11, achieving preliminary purification of the organic waste gas. During this stage, the nitrogen circulation purification mechanism 4 and the nitrogen swirl pulse mechanism 2 are in standby mode, and the stepped heat exchange mechanism 3 only maintains basic ventilation, preparing for the subsequent desorption stage.

[0043] When the activated carbon bed assembly 12 reaches adsorption saturation, the device switches to desorption mode. The nitrogen cyclone pulse mechanism 2 and the adsorption-desorption tower mechanism 1 work together to complete the desorption of organic components. Specifically, the nitrogen supplied by the nitrogen source first enters the nitrogen heater 23 of the nitrogen cyclone pulse mechanism 2 and is heated to a preset desorption temperature to meet the desorption requirements of different VOCs components. The heated nitrogen is then introduced into the cyclone generator 21. Through the tangential air intake of the tangential air inlet pipe 211, combined with the guidance of the guide cone 212 and the adjustment of the cyclone intensity regulating blade 213, a stable cyclone nitrogen flow is formed. After the flow rate of the cyclone nitrogen flow is precisely controlled by the electric regulating valve 22, it is introduced into the nitrogen distribution assembly 13 at the bottom of the inner cavity of the tower body 11 through the air inlet at the bottom of the tower body 11.

[0044] The swirling nitrogen flow entering the nitrogen distribution assembly 13 is first ejected through the concentrically arranged air distribution holes on the bottom plate 131 of the distributor. The swirling effect is further enhanced by the swirling guide vanes 132 directly above each air distribution hole, which form an angle of 30°-60° with the bottom plate, transforming the vertically upward nitrogen flow into a rotating upward swirling flow. Subsequently, the swirling flow is uniformly covered on the lower surface of the lower activated carbon bed 122 by the flow equalization effect of the flow equalization porous plate 133, and permeates through the lower activated carbon bed 122 from top to bottom.

[0045] When the nitrogen gas flow reaches the nitrogen redistribution chamber 14 between the upper activated carbon bed 121 and the lower activated carbon bed 122, part of the supplementary nitrogen enters the nitrogen redistribution chamber 14 through the supplementary nitrogen pipe on the side wall of the tower body 11 and the tangential air inlet of the annular gas collecting chamber 141. After merging with the original swirling nitrogen flow, it diffuses evenly through the diffusion holes with increasing aperture on the surface of the conical diffuser 142. Then, through the rectification effect of the rectifier grid 143, it enters the upper activated carbon bed 121 vertically upward, avoiding the phenomenon of local "short circuit" in the nitrogen flow within the bed. At the same time, it prevents local overheating or underheating of the bed, ensuring uniform temperature distribution between the upper and lower activated carbon beds. The swirling nitrogen flow makes full contact with the activated carbon particles, efficiently desorbing the organic components adsorbed on the surface of the activated carbon, forming a high-temperature desorbed waste gas nitrogen + organic vapor mixture containing high concentrations of organic components.

[0046] High-temperature desorption waste gas containing high concentrations of organic components enters the stepped heat exchange mechanism 3 through the gas outlet at the top of the tower 11. The waste heat in the waste gas is fully recovered through the three-stage heat exchange design, achieving energy saving and consumption reduction, while completing the initial condensation of organic components.

[0047] In the first step, the high-temperature desorption waste gas enters the high-temperature waste gas channel 311b of the primary gas-to-gas heat exchanger 31, where it exchanges heat with the low-temperature circulating nitrogen in the low-temperature nitrogen channel 311c. The high-temperature waste gas releases heat, preheating the low-temperature circulating nitrogen and initially lowering its own temperature. The nitrogen in the low-temperature nitrogen channel 311c comes from the recycled nitrogen of the nitrogen circulation purification mechanism 4. The preheated nitrogen is directly introduced into the nitrogen heater 23, significantly reducing the heating load on the nitrogen heater 23 and decreasing energy consumption. During this process, the heat bypass regulating valve 312 automatically adjusts the proportion of bypass nitrogen based on the preheated nitrogen temperature, ensuring that the nitrogen temperature entering the nitrogen heater 23 remains stable at the preset desorption temperature.

[0048] In the second step, the desorbed waste gas, after being cooled by the first-stage heat exchange, enters the spiral coil 321 of the second-stage gas-liquid heat exchanger 32 and exchanges heat with the phase change heat storage material filling layer 322 on the outside of the spiral coil 321. The phase change heat storage material absorbs and stores the residual heat in the waste gas, further reducing the temperature of the desorbed waste gas. At the same time, the temperature sensor 322a monitors the phase change state of the phase change heat storage material in real time to ensure stable heat exchange efficiency. The non-condensable gases generated during the heat exchange process are discharged through the float-type automatic exhaust valve 323 set at the highest point of the spiral coil 321 to prevent gas resistance from affecting the heat exchange effect.

[0049] The third step involves the desorbed waste gas, after secondary heat exchange, entering the tertiary condenser 33, where it is further cooled to the condensation temperature of the organic components, causing the high-concentration organic vapor to condense into a liquid solvent. The organic solvent can then be recovered and reused through a separation and collection device, thus completing the resource recovery of the organic waste gas.

[0050] After being treated by the three-stage condenser 33, most of the organic components in the desorption waste gas are condensed and recovered. The remaining nitrogen gas, containing trace amounts of oxygen, moisture and uncondensed trace amounts of organic vapor, enters the nitrogen circulation purification unit 4. After purification, it is reused in the desorption process, realizing a closed-loop nitrogen circulation, reducing operating costs, and eliminating safety hazards.

[0051] The specific purification process is as follows: Nitrogen gas containing trace impurities first enters the circulating fan 41, and after being pressurized by the fan, it is passed into the deoxygenation catalytic reactor 42. The trace oxygen accumulated in the nitrogen gas is removed through the catalytic reaction, eliminating the risk of combustion and explosion caused by the mixing of organic vapor and oxygen. The deoxygenated nitrogen gas enters the dew point control component 43, and first passes through two alternating molecular sieve adsorption towers 431. One molecular sieve adsorption tower 431 performs deep drying of the nitrogen gas, removes the moisture in the nitrogen gas, lowers the nitrogen dew point, and avoids the moisture affecting the purity of the subsequent organic solvent recovery. The other tower is used for regeneration. The alternation of the two towers is achieved through the first switching valve 431d to ensure the continuous and stable drying process.

[0052] The regeneration process of the molecular sieve adsorption tower 431 is completed through the electrically heated regeneration pipeline 432: part of the nitrogen in the circulating nitrogen main pipe enters the regeneration nitrogen pipeline 432b, is heated by the electric heater 432a, and is then introduced into the top of the molecular sieve adsorption tower 431 to be regenerated through the second switching valve 431e to perform countercurrent heating regeneration of the molecular sieve and desorb the water adsorbed in the molecular sieve; the regenerated nitrogen containing water is discharged from the bottom of the molecular sieve adsorption tower 431 and enters the gas-liquid separator 433 through the third switching valve 431f. The nitrogen after the water is separated is introduced into the nitrogen heater 23 to participate in the desorption process of the next cycle.

[0053] The purified nitrogen gas, after being dried and deoxygenated by the dew point control component 43, is finally introduced into the nitrogen heater 23, where it merges with the nitrogen gas preheated by the primary gas-gas heat exchanger 31 and re-enters the vortex generator 21 to form a swirling nitrogen gas flow, thus realizing a closed-loop recycling of nitrogen gas. During the entire cycle, the nitrogen gas consumption is only to replenish the leakage, which greatly reduces the nitrogen gas consumption cost.

[0054] This embodiment of the activated carbon nitrogen desorption organic waste gas high-efficiency recovery device treats typical VOCs waste gas from the chemical industry (containing benzene, toluene, etc., with an inlet concentration of 800 mg / m³). Under the conditions of a desorption temperature of 120℃ and a stable nitrogen flow rate, the activated carbon bed desorption efficiency can reach 91.2%-93.5% after 4 hours of cyclone desorption. In traditional vertical airflow desorption, the proportion of local contact blind zones in the bed is 12%-15%, indicating a significant short-circuit phenomenon. This device uses cyclone guide vanes (30°-60° angle) in combination with a flow-equalizing perforated plate, allowing the cyclone nitrogen flow to uniformly cover the entire activated carbon bed, reducing the contact blind zone proportion to 2.1%-3.5% and improving contact uniformity by more than 75%. The device has been running continuously and stably for 1000 hours, with a desorption efficiency consistently above 91%. It exhibits excellent overall operational stability and is suitable for the actual needs of VOCs treatment in various industrial scenarios such as chemical, coating, and printing industries, and can operate continuously for extended periods.

[0055] It should be stated that the above-described invention content and specific embodiments are intended to demonstrate the practical application of the technical solution provided by this invention and should not be construed as limiting the scope of protection of this invention. Those skilled in the art can make various modifications, equivalent substitutions, or improvements within the spirit and principles of this invention. The scope of protection of this invention is determined by the appended claims.

Claims

1. An activated carbon nitrogen desorption organic waste gas efficient recovery device, characterized in that, It includes an adsorption-desorption tower mechanism (1), a nitrogen cyclone pulse mechanism (2), a stepped heat exchange mechanism (3), and a nitrogen circulation purification mechanism (4); the nitrogen cyclone pulse mechanism (2) is connected to the bottom inlet of the adsorption-desorption tower mechanism (1), the stepped heat exchange mechanism (3) is connected to the top outlet of the adsorption-desorption tower mechanism (1), one end of the nitrogen circulation purification mechanism (4) is connected to the outlet of the stepped heat exchange mechanism (3), and the other end of the nitrogen circulation purification mechanism (4) is connected to the inlet of the nitrogen cyclone pulse mechanism (2); wherein: The adsorption-desorption tower mechanism (1) includes a tower body (11), an activated carbon bed assembly (12), and a nitrogen distribution assembly (13); the activated carbon bed assembly (12) is fixedly installed in the middle of the inner cavity of the tower body (11), and the nitrogen distribution assembly (13) is fixedly installed at the bottom of the inner cavity of the tower body (11) and connected to the bottom air inlet; The nitrogen swirling pulse mechanism (2) includes a swirling generator (21), an electric regulating valve (22), and a nitrogen heater (23); the outlet end of the swirling generator (21) is connected to the bottom air inlet of the adsorption-desorption tower mechanism (1) and an electric regulating valve (22) is installed on the connecting pipe; the inlet end of the swirling generator (21) is connected to the outlet end of the nitrogen heater (23) to send the heated nitrogen into the adsorption-desorption tower mechanism (1); The cascade heat exchange mechanism (3) includes a first-stage gas-to-gas heat exchanger (31), a second-stage gas-liquid heat exchanger (32), and a third-stage condenser (33). The high-temperature side inlet of the first-stage gas-to-gas heat exchanger (31) is connected to the top outlet of the adsorption-desorption tower mechanism (1), the low-temperature side outlet of the first-stage gas-to-gas heat exchanger (31) is connected to the inlet of the nitrogen heater (23) of the nitrogen swirl pulse mechanism (2), the high-temperature side outlet of the first-stage gas-to-gas heat exchanger (31) is connected to the high-temperature side inlet of the second-stage gas-liquid heat exchanger (32), and the high-temperature side outlet of the second-stage gas-liquid heat exchanger (32) is connected to the inlet of the third-stage condenser (33), so that the high-temperature desorbed waste gas and the low-temperature nitrogen gas can exchange heat in stages to recover waste heat. The nitrogen circulation purification mechanism (4) includes a circulating fan (41), an oxygen removal catalytic reactor (42), and a dew point control component (43). The inlet end of the circulating fan (41) is connected to the outlet end of the three-stage condenser (33) of the stepped heat exchange mechanism (3). The outlet end of the circulating fan (41) is connected to the inlet end of the oxygen removal catalytic reactor (42). The outlet end of the oxygen removal catalytic reactor (42) is connected to the dew point control component (43). The dew point control component (43) is connected to the inlet of the nitrogen heater (23) of the nitrogen swirl pulse mechanism (2) to realize the reuse of circulating nitrogen after oxygen removal and drying.

2. The active carbon nitrogen desorption organic waste gas high-efficiency recovery device according to claim 1, characterized in that, The nitrogen distribution assembly (13) includes a distributor base plate (131), a swirl guide vane (132), and a flow equalization porous plate (133). The distributor base plate (131) has multiple air distribution holes arranged in concentric circles. A swirl guide vane (132) is fixed directly above each air distribution hole. The swirl guide vane (132) forms an angle of 30°-60° with the distributor base plate (131) to transform the nitrogen flow vertically upward from the air distribution hole into a rotating upward nitrogen flow, thereby increasing the contact area between the nitrogen and the activated carbon bed. The flow equalization porous plate (133) is fixed above the swirl guide vane (132), and the flow equalization porous plate (133) has multiple flow equalization holes to evenly distribute the rotating upward nitrogen flow, ensuring that the nitrogen after equalization can uniformly cover the entire activated carbon bed.

3. The active carbon nitrogen desorption organic waste gas high-efficiency recovery device according to claim 2, characterized in that, The diameter of the air distribution holes on the distributor base plate (131) is 5-15 mm and the opening rate is 15%-25%; the diameter of the flow equalization holes on the flow equalization porous plate (133) is 2-5 mm and the opening rate is 40%-60%; the flow equalization porous plate (133) is 100-200 mm away from the lower surface of the activated carbon bed assembly (12).

4. The activated carbon nitrogen desorption organic waste gas high-efficiency recovery device according to claim 1, characterized in that, The activated carbon bed assembly (12) includes an upper activated carbon bed (121) and a lower activated carbon bed (122); a nitrogen redistribution chamber (14) is provided between the upper activated carbon bed (121) and the lower activated carbon bed (122); The nitrogen redistribution chamber (14) includes an annular gas collection chamber (141), a conical diffuser (142), and a rectifier grid (143). The large end of the conical diffuser (142) faces upward and is close to the lower surface of the upper activated carbon bed (121), and the small end of the conical diffuser (142) is connected to the annular gas collection chamber (141). The surface of the conical diffuser (142) is provided with multiple diffusion holes, and the diameter of the multiple diffusion holes gradually increases from the small end to the large end. The side wall of the annular gas collection chamber (141) is provided with a tangential air inlet, which is connected to the supplementary nitrogen pipe on the side wall of the tower body (11). The rectifier grid (143) is composed of multiple layers of staggered horizontal grid bars, and the rectifier grid (143) is located above the conical diffuser (142) so that nitrogen enters the upper activated carbon bed (121) vertically.

5. The active carbon nitrogen desorption organic waste gas high-efficiency recovery device according to claim 4, characterized in that, The diameter of the diffuser hole at the small end of the conical diffuser hood (142) is 3-5 mm, and the diameter of the diffuser hole at the large end is 8-12 mm; the horizontal spacing between the center lines of two adjacent horizontal grid bars in each layer of the rectifier grid (143) is 10-20 mm, and the thickness of a single horizontal grid bar is 20-30 mm.

6. The activated carbon nitrogen desorption organic waste gas high-efficiency recovery device according to claim 1, characterized in that, The swirl generator (21) includes a tangential inlet pipe (211), a guide cone (212), and a swirl intensity regulating blade (213). The tangential inlet pipe (211) is fixedly welded to the tangential direction of the swirl generator (21), and the swirl intensity regulating blade (213) is rotatably disposed inside the tangential inlet pipe (211) to change the tangential velocity component of the nitrogen gas entering. The guide cone (212) is fixedly disposed at the central axis position of the swirl generator (21) to guide the nitrogen gas to form a stable swirl field.

7. The activated carbon nitrogen desorption organic waste gas high-efficiency recovery device according to claim 1, characterized in that, The primary gas-to-gas heat exchanger (31) includes a plate heat exchange core (311) and a heat bypass regulating valve (312); wherein, The plate heat exchange core (311) is composed of multiple corrugated plates (311a) stacked together. The corrugation directions of adjacent corrugated plates (311a) are opposite to form a mesh flow channel and form alternating high-temperature exhaust gas channels (311b) and low-temperature nitrogen channels (311c). The inlet of the high-temperature exhaust gas channel (311b) is connected to the top outlet of the adsorption-desorption tower mechanism (1), and the outlet of the high-temperature exhaust gas channel (311b) is connected to the high-temperature side inlet of the secondary gas-liquid heat exchanger (32). The outlet of the low-temperature nitrogen channel (311c) is connected to the inlet of the nitrogen heater (23) of the nitrogen swirl pulse mechanism (2). The hot bypass regulating valve (312) is an electric three-way regulating valve. The inlet of the hot bypass regulating valve (312) is connected to the low-temperature nitrogen source, the first outlet is connected to the inlet of the low-temperature nitrogen channel (311c), and the second outlet is connected to the connecting pipe between the outlet of the low-temperature nitrogen channel (311c) and the inlet of the nitrogen heater (23) through the bypass pipe, so as to adjust the ratio of bypass nitrogen according to the nitrogen temperature.

8. The activated carbon nitrogen desorption organic waste gas high-efficiency recovery device according to claim 1, characterized in that, The secondary gas-liquid heat exchanger (32) includes a spiral coil (321), a phase change heat storage material filling layer (322), and an automatic exhaust valve (323). The spiral coil (321) is fixed inside the shell of the secondary gas-liquid heat exchanger (32) for the flow of desorbed waste gas. The phase change heat storage material filling layer (322) is filled between the spiral coil (321) and the shell. A temperature sensor (322a) is embedded in the phase change heat storage material filling layer (322) for monitoring the phase change state. The automatic exhaust valve (323) is a float-type exhaust valve. The automatic exhaust valve (323) is located at the highest point of the spiral coil (321) for discharging non-condensable gases and preventing gas blockage.

9. The activated carbon nitrogen desorption organic waste gas high-efficiency recovery device according to claim 1, characterized in that, The dew point control assembly (43) includes a molecular sieve adsorption tower (431), an electrically heated regeneration pipeline (432), and a gas-liquid separator (433). Two molecular sieve adsorption towers (431) are provided, both of which are vertical cylindrical. A wire mesh demister (431a) is provided at the top of the molecular sieve adsorption tower (431), and a support grid (431b) and a ceramic ball support layer (431c) are provided at the bottom of the molecular sieve adsorption tower (431). The two molecular sieve adsorption towers (431) are connected to the outlet end of the deoxygenation catalytic reactor (42) through a first switching valve (431d) to achieve alternating operation and regeneration. The electric heating regeneration pipeline (432) includes an electric heater (432a) and a regeneration nitrogen pipeline (432b); the inlet of the regeneration nitrogen pipeline (432b) is connected to the main circulating nitrogen pipe, and the outlet of the regeneration nitrogen pipeline (432b) is connected to the top regeneration inlet of the two molecular sieve adsorption towers (431) via the electric heater (432a) and the second switching valve (431e); the bottom regeneration outlet of the two molecular sieve adsorption towers (431) is connected to the inlet of the gas-liquid separator (433) via the third switching valve (431f), and the outlet of the gas-liquid separator (433) is connected to the inlet of the nitrogen heater (23) of the nitrogen swirl pulse mechanism (2) to achieve countercurrent heating regeneration.

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