A device for treating activated carbon regeneration tail gas

Abstract

The application relates to the technical field of tail gas treatment, in particular to a treatment device for activated carbon regeneration tail gas, which comprises a shell, a stripping assembly and a cooling assembly. The shell is internally sequentially and communicatively provided with a stripping cavity and a cooling cavity from top to bottom. The stripping assembly is coaxially arranged in the stripping cavity. The cooling assembly is arranged in the cooling cavity and is in communication with the stripping assembly. After entering the shell through the upper port of the shell, the tail gas is first stripped of catalytic fly ash by the stripping assembly in the stripping cavity, and then is rapidly cooled by the cooling assembly in the cooling cavity. The stripping assembly and the cooling assembly can rapidly and sufficiently cool the catalytic fly ash in the tail gas after stripping, avoid the formation of dioxin synthesis conditions, and effectively protect the environment.

Description

Technical Field

[0001] This invention relates to the field of exhaust gas treatment technology, specifically to a treatment device for activated carbon regeneration exhaust gas. Background Technology

[0002] In the construction of environmental protection projects and ecological protection projects under the advanced environmental protection industry, there are strict requirements for the standards of waste gas emissions. Among them, activated carbon is widely used in environmental protection projects for waste gas adsorption due to its highly efficient adsorption and separation effect.

[0003] Existing activated carbon adsorption equipment typically uses granular activated carbon and honeycomb activated carbon. During operation, it relies solely on the adsorption effect of the activated carbon to adsorb exhaust gases. The adsorption capacity of unregenerated activated carbon decreases with repeated use, making recycling impossible and thus reducing adsorption efficiency. To address this issue, existing technologies offer relatively good solutions, such as a method for treating and regenerating benzaldehyde production exhaust gas (publication number CN106621695B). This method treats benzaldehyde exhaust gas generated during dibenzyl ether oxidation by introducing the exhaust gas into multiple activated carbon adsorption devices for multi-level adsorption. Periodic steam desorption is used to regenerate the activated carbon, ensuring continuous adsorption and improving efficiency while also addressing the environmental impact of the exhaust gas. However, this method still has the following drawbacks: the pyrolysis exhaust gas of waste activated carbon (especially activated carbon from the chemical, pesticide, and waste incineration industries) contains large amounts of chlorine sources and aromatic precursors. Furthermore, the activated carbon powder and fly ash entrained in the exhaust gas are rich in metals such as copper and iron. When high-temperature exhaust gas is discharged and heat is recovered, if the cooling rate is not fast enough, the flue gas will stay in the 200℃~500℃ temperature window for too long. The copper and iron ions on the fly ash surface will strongly catalyze the secondary synthesis of precursors, resulting in dioxins exceeding the standard in the exhaust gas, which will also have a negative impact on the environment.

[0004] Therefore, in order to solve the above problems, a treatment device for activated carbon regeneration tail gas is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a treatment device for activated carbon regeneration tail gas, which solves the problem that dioxins are formed during the treatment of waste activated carbon pyrolysis tail gas, causing negative environmental impacts. Through the inclusion of a stripping component and a cooling component, the catalytic fly ash in the tail gas can be rapidly and sufficiently cooled after stripping, avoiding the conditions for dioxin synthesis and achieving effective environmental protection.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A device for treating activated carbon regeneration exhaust gas includes a shell, a stripping component, and a cooling component. The shell has a stripping chamber and a cooling chamber connected sequentially from top to bottom. The stripping component is coaxially disposed in the stripping chamber, and the cooling component is disposed in the cooling chamber and connected to the stripping component. After the exhaust gas enters the shell through the upper port, it first passes through the stripping component in the stripping chamber to strip catalytic fly ash, and then passes through the cooling component in the cooling chamber for rapid cooling.

[0007] Preferably, the stripping assembly includes a housing, a spiral guide vane, and an anti-vortex cone. The housing is disposed inside the stripping chamber and its top end is sealed and fixed to the inner wall of the stripping chamber. The spiral guide vane is disposed on the top of the housing. The side wall of the housing is provided with a ash discharge pipe that extends through to the outside of the housing. A discharge valve is provided on the ash discharge pipe. The anti-vortex cone is disposed inside the housing and is a frustum-shaped cone with its tip pointing upwards.

[0008] Preferably, the cooling component includes an air pipe, an annular pipe, and a water inlet pipe. The air pipe is disposed inside the housing and includes a contraction section, a throat section, and a diffusion section connected sequentially from top to bottom. The annular pipe is coaxially sleeved on the throat section. The water inlet pipe is disposed on the annular pipe and communicates with the inside of the annular pipe. A guide pipe is disposed between the annular pipe and the throat section to connect the two. A high-pressure atomizing nozzle is disposed at one end of the guide pipe located inside the throat section.

[0009] Preferably, the housing includes an upper section and a lower section connected from top to bottom. The upper section is cylindrical, and the lower section is frustum-shaped with a tapered bottom. The outer surface of the anti-vortex cone has a plurality of connecting plates arranged in a circumferential array, and is fixedly connected to the inner wall of the lower section through the plurality of connecting plates. The spiral guide vane is disposed at the top port of the upper section. The top of the tapered section is fixedly connected to the bottom of the lower section. The inner wall of the lower section has a peeling groove, and the inlet end of the ash discharge pipe extends into the peeling groove.

[0010] Preferably, the connecting plate is spirally arranged, and the spiral direction is the same as the spiral direction of the spiral guide vane.

[0011] Preferably, the helix angle of the connecting plate is smaller than the helix angle of the helical guide vane.

[0012] Preferably, the spray direction of the high-pressure atomizing nozzle is opposite to the spiral direction of the spiral guide vane, the projection of the spray axis of the high-pressure atomizing nozzle onto the radial cross-sectional circle of the throat section makes an angle of 30° to 45° with the tangent of the cross-sectional circle of the throat section, and the spray axis of the high-pressure atomizing nozzle is inclined upward.

[0013] Preferably, the depth of the stripping groove increases from top to bottom, and the groove opening faces the opposite direction to the spiral direction of the spiral guide blade.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Through the set stripping component, the centrifugal force generated by the exhaust gas entering the shell and cooperating with the spiral guide vanes is used to efficiently centrifugally strip the activated carbon micro powder and catalytic fly ash rich in metal elements such as copper and iron carried in the high-temperature exhaust gas into the stripping tank and smoothly discharge it. This effectively curbs the secondary flying and escape of fly ash, and allows the metal catalytic components in the exhaust gas to be removed before entering the cooling stage, thereby avoiding the secondary synthesis of dioxins. This creates a clean gas phase environment without catalytic interference for the subsequent cooling process, and achieves effective environmental protection.

[0015] 2. By using the cooling components, after stripping and removing catalytic fly ash, the cooling water is turned into droplets by the shear force generated by the narrowing of the pipe and the high-pressure atomizing nozzles in the opposite direction. This achieves rapid vaporization and heat absorption of the cooling water in the throat section, which greatly improves the cooling rate of the high-temperature exhaust gas. This allows the exhaust gas to cross the sensitive temperature window for dioxin secondary synthesis in a very short time, solving the problem of insufficient cooling rate causing the flue gas to stay in the sensitive temperature window for too long, and further avoiding the synthesis of dioxins. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a partial cross-sectional view of the present invention; Figure 3 This is a partial cross-sectional view of the connection structure between the stripping component and the cooling component of the present invention; Figure 4 This is a partial cross-sectional view of the cooling component of the present invention; Figure 5 For the present invention Figure 3 Enlarged view of section A; Figure 6 This is a schematic cross-sectional view of the connection structure between the housing, the spiral guide vane, and the anti-vortex cone of the present invention.

[0017] In the diagram: 1. Outer shell; 11. Peeling chamber; 12. Cooling chamber; 2. Peeling assembly; 21. Shell; 211. Upper section; 212. Lower section; 213. Peeling groove; 22. Spiral guide vane; 23. Anti-vortex cone; 24. Ash discharge pipe; 25. Discharge valve; 26. Connecting plate; 3. Cooling assembly; 31. Air pipe; 311. Contraction section; 312. Throat section; 313. Diffusion section; 32. Annular pipe; 33. Water inlet pipe; 34. Guide pipe; 35. High-pressure atomizing nozzle. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0019] Please see Figures 1 to 6 This invention provides a device for treating activated carbon regeneration tail gas, the technical solution of which is as follows: For details, please refer to Figure 1 and Figure 2 A device for treating activated carbon regeneration tail gas includes a shell 1, a stripping component 2, and a cooling component 3. The shell 1 has a stripping chamber 11 and a cooling chamber 12 connected sequentially from top to bottom inside. The stripping component 2 is coaxially disposed in the stripping chamber 11, and the cooling component 3 is disposed in the cooling chamber 12 and connected to the stripping component 2. Since the high-temperature tail gas contains catalytic fly ash, the tail gas enters the shell 1 through the upper port and first passes through the stripping component 2 in the stripping chamber 11 to strip the catalytic fly ash, and then passes through the cooling component 3 in the cooling chamber 12 for rapid cooling.

[0020] As one embodiment of the present invention, refer to Figure 1 , Figure 2 and Figure 3 The stripping assembly 2 includes a housing 21, a spiral guide vane 22, and an anti-vortex cone 23. The housing 21 is disposed inside the stripping chamber 11 and its top end is sealed and fixed to the inner wall of the stripping chamber 11. The spiral guide vane 22 is disposed on the top of the housing 21. A ash discharge pipe 24 is disposed on the side wall of the housing 21 and extends to the outside of the outer shell 1. A discharge valve 25 is disposed on the ash discharge pipe 24. The anti-vortex cone 23 is disposed inside the housing 21 and is in the shape of a frustum with its tip pointing upward. An annular gap is provided between the anti-vortex cone 23 and the housing 21 to allow exhaust gas to pass through.

[0021] In the high-temperature regeneration process of spent activated carbon in industries such as chemical, pesticide, and waste incineration, the generated pyrolysis tail gas not only contains a large amount of chlorine sources and aromatic precursors, but also carries activated carbon micropowder and catalytic fly ash rich in metal elements such as copper and iron. In actual tail gas treatment operations, if the untreated high-temperature tail gas is directly introduced into the subsequent cooling or waste heat recovery stage, when the tail gas passes through the sensitive temperature range of 200℃ to 500℃, the copper, iron, and other metal ions enriched on the fly ash surface will act as highly efficient catalysts, strongly catalyzing the secondary synthesis of gaseous precursors, thereby generating highly toxic dioxin-like substances, leading to serious exceedances of tail gas emissions.

[0022] Therefore, by adopting the above-described implementation method, when the high-temperature exhaust gas enters from the top of the shell 21, the spiral guide vanes 22 forcefully guide the airflow to form a high-speed vortex. Using centrifugal force, the catalytic fly ash rich in metal ions such as copper and iron is quickly thrown towards the inner wall of the shell 21 and settles along the wall surface, achieving efficient separation of fly ash from exhaust gas. At the same time, the truncated cone 23 with its tip pointing upwards inside the shell 21 can effectively block the formation of a strong vortex at the bottom of the airflow, preventing the separated and settled fly ash from being entrained and rolled up again by the rotating airflow. The separated and collected fly ash is periodically discharged through the ash discharge pipe 24 and the discharge valve 25, which greatly reduces the content of catalytically active substances in the exhaust gas. This provides a clean gas phase environment without catalytic interference for the subsequent exhaust gas to enter the cooling chamber 12 for rapid cooling, effectively suppressing the secondary generation of dioxins and ensuring that the exhaust gas treated by activated carbon regeneration meets emission standards.

[0023] As one embodiment of the present invention, refer to Figure 2 , Figure 3 and Figure 4 The cooling component 3 includes an air pipe 31, an annular pipe 32, and a water inlet pipe 33. The air pipe 31 is located inside the housing 21 and includes a contraction section 311, a throat section 312, and a diffuser section 313 connected sequentially from top to bottom. The annular pipe 32 is coaxially sleeved on the throat section 312. The water inlet pipe 33 is located on the annular pipe 32 and communicates with the inside of the annular pipe 32. A guide pipe 34 is provided between the annular pipe 32 and the throat section 312 to connect the two. A high-pressure atomizing nozzle 35 is provided at one end of the guide pipe 34 located inside the throat section 312.

[0024] Since the exhaust gas after the catalytic fly ash has been stripped is still at a high temperature, if conventional cooling methods such as direct spraying or indirect heat exchange are used, the gas will remain in the sensitive temperature window of 200℃ to 500℃ for too long due to the small gas-liquid contact area and slow heat exchange rate. This will also trigger the secondary synthesis of residual precursors. At the same time, traditional spray cooling methods often result in uneven atomization and large droplet size, which prevents the cooling water from completely vaporizing and absorbing heat. This not only leads to low cooling efficiency but also easily causes sewage accumulation and acid corrosion at the bottom of the equipment.

[0025] Therefore, in the above-described embodiment, when the high-temperature exhaust gas accelerates into the throat section 312 after passing through the contraction section 311, the contraction of the flow channel cross-section will cause the exhaust gas to undergo strong narrowing acceleration, thereby forming an extremely high gas velocity and a local low-pressure area; the fine water mist sprayed by the high-pressure atomizing nozzle 35 in the throat section 312 is further broken up under the huge shear force of the high-speed airflow, greatly increasing the gas-liquid contact area, and the cooling water quickly absorbs the heat of the exhaust gas and vaporizes instantly; this allows the high-temperature exhaust gas to quickly pass through the dioxin-sensitive temperature window of 200℃~500℃ in a very short time, thereby cutting off the conditions for secondary dioxin synthesis; in addition, the annular balanced water supply structure of the ring pipe 32 and the guide pipe 34 ensures the uniformity and vaporization rate of the spray from the high-pressure atomizing nozzle 35, avoids equipment inner wall corrosion and dust accumulation caused by liquid water droplet residue, and significantly improves the cooling efficiency and long-term continuous operation reliability of the device.

[0026] As one embodiment of the present invention, refer to Figure 3 , Figure 5 and Figure 6 The housing 21 includes an upper section 211 and a lower section 212 connected from top to bottom. The upper section 211 is cylindrical, and the lower section 212 is frustum-shaped with a constricted bottom. The outer surface of the anti-vortex cone 23 has a circumferential array of multiple connecting plates 26, which are fixedly connected to the inner wall of the lower section 212 through the multiple connecting plates 26. The spiral guide vane 22 is disposed at the top port of the upper section 211. The top of the constriction section 311 is fixedly connected to the bottom of the lower section 212. The inner wall of the lower section 212 is provided with a peeling groove 213, and the inlet end of the ash discharge pipe 24 extends into the peeling groove 213. The depth of the peeling groove 213 increases from top to bottom, and the groove opening of the peeling groove 213 faces the opposite direction to the spiral direction of the spiral guide vane 22.

[0027] By adopting the above-described implementation method, on the one hand, since the opening of the stripping tank 213 faces the opposite direction to the swirling flow guided by the spiral guide vane 22, the fly ash rotating at high speed along the inner wall will directly enter the stripping tank 213 and be blocked by the tank wall of the stripping tank 213, thus entering the relatively static tank space. This achieves effective isolation between the fly ash and the high-speed main airflow, thereby avoiding secondary blowing and entrainment of the fly ash by the high-speed rotating airflow. On the other hand, the depth of the stripping tank 213 is set to increase from top to bottom, so that the fly ash can settle and collect from top to bottom. This provides a smooth downward channel with increasing space for the collected fly ash and accurately guides it to the inlet end of the ash discharge pipe 24. This not only improves the collection efficiency and ash discharge smoothness of the catalytic fly ash, but also avoids the problem of fly ash escaping to the subsequent cooling section and causing secondary dioxin synthesis.

[0028] As one embodiment of the present invention, refer to Figure 3 and Figure 6The connecting plate 26 is spirally arranged, and the spiral direction is the same as that of the spiral guide vane 22; the spiral helix angle of the connecting plate 26 is smaller than that of the spiral guide vane 22.

[0029] By adopting the above-described implementation method, the connecting plate 26 is designed in a spiral shape, with its spiral direction being the same as that of the spiral guide vane 22 and its spiral angle being smaller than that of the guide vane. This achieves smooth guidance and low-resistance rectification of the high-speed swirling flow. The connecting plate 26, with its spiral arrangement in the same direction, works in conjunction with the exhaust gas after being guided by the spiral guide vane 22, avoiding direct obstruction and violent impact on the airflow and significantly reducing the aerodynamic resistance of the airflow when passing through the support area of ​​the anti-vortex cone 23. At the same time, the connecting plate 26 with its smaller spiral angle plays a role in gradually rectifying and moderately slowing the flow of the high-speed swirling flow. It retains the centrifugal force required for the centrifugal settling of fly ash while smoothing the intensity of the rotation of the bottom airflow, eliminating the impact interference of local turbulence and vortices on the fly ash particles. This allows the stripped fly ash to slide smoothly along a stable and smooth trajectory and flow into the stripping groove 213, effectively ensuring the stripping effect of the fly ash particles.

[0030] As one embodiment of the present invention, refer to Figure 3 and Figure 4 The spray direction of the high-pressure atomizing nozzle 35 is opposite to the spiral direction of the spiral guide vane 22. The projection of the spray axis of the high-pressure atomizing nozzle 35 onto the radial cross-sectional circle of the throat section 312 is set at an angle of 30° to 45° with the tangent of the cross-sectional circle of the throat section 312. The spray axis of the high-pressure atomizing nozzle 35 is inclined upward.

[0031] In the above-described embodiment, the upward and reverse jet direction of the high-pressure atomizing nozzle 35 creates a strong gas-liquid countercurrent, maximizing the relative velocity between the water mist and the downward swirling exhaust gas. The enormous shear force of the airflow tears the water mist into droplets. The upward-inclined jet axis increases the travel distance of the water mist within the throat section 312, promoting rapid vaporization and heat absorption, and prolonging the contact mixing time of the gas and liquid phases under intense turbulence. The tangential angle of 30° to 45° ensures that the water mist achieves full-section coverage without dead angles, further guaranteeing the treatment effect on the exhaust gas.

[0032] Working principle: After the high-temperature regeneration exhaust gas enters the stripping chamber 11 from the upper port of the outer shell 1, it is first forcibly guided by the spiral guide vanes 22 at the top port of the upper section 211 to form a high-speed rotating airflow. Since the inner diameter of the lower section 212 decreases from top to bottom, the tangential velocity increases rapidly as the airflow enters the lower section 212, thereby throwing the catalytic fly ash entrained in the exhaust gas onto the inner wall of the lower section 212 under the action of centrifugal force. The fly ash that rolls down the wall is intercepted by the stripping groove 213 and embedded in the stripping groove 213, and finally collects and falls into the inlet end of the ash discharge pipe 24. Opening the discharge valve 25 allows the catalytic fly ash to be discharged outside the outer shell 1 through the ash discharge pipe 24. At the same time, the airflow passes downward through the anti-vortex cone 23, and the high-speed rotating airflow is smoothly rectified in the forward direction under the action of the connecting plate 26. The anti-vortex cone 23 blocks the bottom vortex and prevents the settled fly ash from being re-entrained. The clean high-temperature exhaust gas after the fly ash is removed flows directly into the lower section 212 from the bottom constriction. The constriction section 311 of the coaxially fixed gas pipe 31 causes the airflow to accelerate rapidly and flow quickly into the throat section 312, forming a low-pressure zone. At the same time, cooling water enters the annular pipe 32 through the inlet pipe 33 and is transported to the high-pressure atomizing nozzle 35 located inside the throat section 312 via the guide pipe 34. Since the spray direction of the high-pressure atomizing nozzle 35 is opposite to the spiral direction of the spiral guide vane 22 and the spray axis is tilted upward, the water flow will be sprayed downward and swirling exhaust gas obliquely in the opposite direction after being sprayed out of the high-pressure atomizing nozzle 35. The strong gas-liquid counter-current collision generates shear force to break the water mist into droplets for the second time. The water mist vaporizes in the throat section 312 and absorbs a large amount of heat from the exhaust gas. Then, the exhaust gas and the vaporized water vapor enter the diffusion section 313 together to expand and slow down, so that the high-temperature exhaust gas is rapidly cooled and quickly passes through the sensitive temperature window for dioxin secondary synthesis, thereby blocking the conditions for dioxin secondary synthesis and achieving effective environmental protection.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for treating activated carbon regeneration tail gas, comprising a housing (1), characterized in that: It also includes a stripping component (2) and a cooling component (3). The shell (1) is provided with a stripping chamber (11) and a cooling chamber (12) connected from top to bottom. The stripping component (2) is coaxially disposed in the stripping chamber (11). The cooling component (3) is disposed in the cooling chamber (12) and connected to the stripping component (2). After the exhaust gas enters the shell (1) through the upper port, it first passes through the stripping component (2) in the stripping chamber (11) to strip the catalytic fly ash, and then passes through the cooling component (3) in the cooling chamber (12) for rapid cooling.

2. The activated carbon regeneration tail gas treatment device according to claim 1, characterized in that: The stripping assembly (2) includes a housing (21), a spiral guide vane (22), and an anti-vortex cone (23). The housing (21) is disposed in the stripping cavity (11) and its top end is sealed and fixed to the inner wall of the stripping cavity (11). The spiral guide vane (22) is disposed on the top of the housing (21). The side wall of the housing (21) is provided with a ash discharge pipe (24) that extends to the outside of the outer shell (1). The ash discharge pipe (24) is provided with a discharge valve (25). The anti-vortex cone (23) is disposed in the housing (21) and is in the shape of a frustum with its tip pointing upward.

3. The activated carbon regeneration tail gas treatment device according to claim 2, characterized in that: The cooling component (3) includes an air pipe (31), an annular pipe (32) and a water inlet pipe (33). The air pipe (31) is located inside the housing (21) and includes a contraction section (311), a throat section (312) and a diffusion section (313) connected sequentially from top to bottom. The annular pipe (32) is coaxially sleeved on the throat section (312). The water inlet pipe (33) is located on the annular pipe (32) and communicates with the inside of the annular pipe (32). A guide pipe (34) is provided between the annular pipe (32) and the throat section (312) to connect the two. A high-pressure atomizing nozzle (35) is provided at one end of the guide pipe (34) located inside the throat section (312).

4. The activated carbon regeneration tail gas treatment device according to claim 3, characterized in that: The housing (21) includes an upper section (211) and a lower section (212) connected from top to bottom. The upper section (211) is cylindrical, and the lower section (212) is frustum-shaped with a constricted bottom. The outer surface of the anti-vortex cone (23) has a circumferential array of multiple connecting plates (26), and is fixedly connected to the inner wall of the lower section (212) through the multiple connecting plates (26). The spiral guide vane (22) is located at the top port of the upper section (211). The top of the contraction section (311) is fixedly connected to the bottom of the lower section (212). The inner wall of the lower section (212) is provided with a peeling groove (213), and the inlet end of the ash discharge pipe (24) extends into the peeling groove (213).

5. The activated carbon regeneration tail gas treatment device according to claim 4, characterized in that: The connecting plate (26) is spirally arranged, and the spiral direction is the same as that of the spiral guide vane (22).

6. The activated carbon regeneration tail gas treatment device according to claim 5, characterized in that: The helix angle of the connecting plate (26) is smaller than that of the helix angle of the helical guide vane (22).

7. The activated carbon regeneration tail gas treatment device according to claim 3, characterized in that: The spray direction of the high-pressure atomizing nozzle (35) is opposite to the spiral direction of the spiral guide vane (22). The projection of the spray axis of the high-pressure atomizing nozzle (35) onto the radial cross-sectional circle of the throat section (312) is set at an angle of 30° to 45° with the tangent of the cross-sectional circle of the throat section (312). The spray axis of the high-pressure atomizing nozzle (35) is inclined upward.

8. The activated carbon regeneration tail gas treatment device according to claim 4, characterized in that: The depth of the stripping groove (213) increases from top to bottom, and the groove opening of the stripping groove (213) faces the opposite direction to the spiral direction of the spiral guide vane (22).

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