A claw type explosion-proof mixing system for high and low concentration VOCs waste gas and a control method thereof

Abstract

The application provides a claw type explosion-proof mixing system and control method for high and low concentration VOCs waste gas, comprising a low-concentration waste gas fan, a high-concentration waste gas fan, a fresh air fan, a premixing tank, a claw type mixer and a control system; the claw type mixer comprises a tank body, an air inlet and an air outlet, the air inlet and the air outlet are arranged at the two axial ends of the tank body respectively, and the air inlet is arranged as a claw type air inlet; the claw type air inlet comprises a plurality of first claw type air inlets, a plurality of second claw type air inlets and a plurality of third claw type air inlets; the output end of the high-concentration waste gas fan is connected to the input end of the premixing tank; the output end of the premixing tank is connected to the input end of each first claw type air inlet; the output end of the low-concentration waste gas fan is connected to the input end of each second claw type air inlet; the output end of the fresh air fan is connected to the input end of each third claw type air inlet; the control system comprises a gas detection module and a valve; the valve is arranged at the input end of the claw type air inlet and used for enabling or closing the claw type air inlet.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection waste gas treatment technology, specifically relating to a claw-type explosion-proof mixing system and control method for high and low concentration VOCs waste gas. Background Technology

[0002] Volatile organic compounds (VOCs) are a class of organic compounds with high vapor pressure at room temperature that are easily volatilized. Their emissions pose a serious threat to the atmospheric environment and human health. Industrial production processes, such as those in the chemical and pharmaceutical industries, generate large amounts of high-concentration VOC waste gas.

[0003] Currently, high-concentration VOCs waste gas is usually treated using combustion processes. However, since VOCs waste gas is flammable and explosive, its concentration must be controlled to be below 25% of the lower explosive limit. Therefore, it is necessary to first mix it with low-concentration VOCs waste gas to make the waste gas concentration below 25% of the lower explosive limit, so that subsequent combustion processes such as regenerative thermal oxidizer (RTO) and catalytic combustion (CO) can be used for treatment under safe conditions.

[0004] However, existing waste gas mixing devices have many problems.

[0005] On the one hand, traditional mixing equipment has a simple structure and poor mixing uniformity, making it difficult to fully and quickly mix high and low concentration exhaust gases. This results in unstable exhaust gas concentrations entering subsequent treatment equipment, which can easily lead to instantaneous concentrations exceeding the lower explosive limit by 25%.

[0006] On the other hand, due to the characteristics of the production conditions, the concentration of high-concentration waste gas is prone to fluctuation, which can lead to unstable concentration after mixing and the concentration being within the explosion limit range. Existing mixing devices lack effective control processes and cannot adjust the mixing process in real time according to parameters such as waste gas concentration and flow rate. They also cannot accurately control the degree of dilution of waste gas. Existing safety interlock control can only shut down the treatment system in an emergency and vent the waste gas in an emergency to avoid explosion.

[0007] Therefore, due to the need for safe treatment of mixed waste gas with high and low concentrations, it is urgent to develop a device and corresponding method that can achieve efficient mixing of waste gas with high and low concentrations of VOCs and is equipped with a precise mixing control process. Summary of the Invention

[0008] The purpose of this invention is to address the problem that the structure and control process of existing industrial VOCs high- and low-concentration waste gas mixing devices cannot meet safety requirements. Therefore, this invention provides a claw-type explosion-proof mixing system and control method for high- and low-concentration VOCs waste gas.

[0009] To achieve the above objectives, the present invention proposes the following technical solution:

[0010] A claw-type explosion-proof mixing system for high and low concentration VOCs exhaust gases includes a low-concentration exhaust gas fan, a high-concentration exhaust gas fan, a fresh air fan, a premixing tank, a claw-type mixer, and a control system.

[0011] The claw mixer includes a tank, an air inlet and an air outlet, with the air inlet and the air outlet respectively located at both ends of the axial direction of the tank, and the air inlet being configured as a claw-type air inlet.

[0012] The claw-shaped air inlet includes several first claw-shaped air inlets, several second claw-shaped air inlets, and several third claw-shaped air inlets;

[0013] The output end of the high-concentration exhaust gas blower is connected to the input end of the premixing tank; the output end of the premixing tank is respectively connected to a plurality of first claw-type air inlet input ends; the output end of the low-concentration exhaust gas blower is respectively connected to a plurality of second claw-type air inlet input ends; the output end of the fresh air blower is respectively connected to a plurality of third claw-type air inlet input ends.

[0014] The control system includes a gas detection module and valves;

[0015] The gas detection module is installed at least at the output end of the low-concentration exhaust gas fan, the high-concentration exhaust gas fan, the fresh air fan, the premix tank, and the claw mixer, and is used to detect gas parameters.

[0016] The valve is located at the input end of the claw-type air inlet and is used to enable or disable the claw-type air inlet.

[0017] The high-concentration exhaust gas delivered by the high-concentration exhaust gas fan enters the premixing tank, where it mixes with the low-concentration exhaust gas delivered by the low-concentration exhaust gas fan and / or the fresh air delivered by the fresh air fan through the claw-type air inlet into the claw mixer. The control system acquires gas parameters through the gas detection module, performs frequency conversion control on the fresh air fan according to the changes in gas parameters, and simultaneously controls the valve to keep the concentration and flow rate of the mixed gas within a set range, thereby achieving control of the mixing system.

[0018] Furthermore, the gas detection module includes a concentration detector and a flow transmitter. The concentration detector is installed at least at the output end of the low-concentration exhaust gas fan, the premixing tank, and the claw mixer. The flow transmitter is installed at least at the output end of the low-concentration exhaust gas fan, the high-concentration exhaust gas fan, and the fresh air fan.

[0019] Furthermore, the claw mixer also includes at least one layer of turbulence-inducing components;

[0020] The turbulence-inducing component includes a fan-shaped swirl plate, specifically including an annular support frame and a rotating component with the axial direction parallel to the tank axis. The outer wall of the annular support frame abuts against the inner wall of the tank, and the rotating component is disposed inside the annular support frame.

[0021] The rotating assembly includes several arc-shaped blades and a rotating shaft located in the axial direction of the annular support frame. The arc-shaped blades are evenly distributed in the annular support frame along the radial direction of the rotating shaft, and one end of the arc-shaped blade away from the rotating shaft is connected to the inner wall surface of the annular support frame.

[0022] The number of arc-shaped blades is set to 8-16, and the angle between the arc-shaped blades and the rotation axis is 45°.

[0023] Furthermore, the claw mixer also includes at least one flow guiding component;

[0024] The flow guiding component includes a single-layer perforated plate, which abuts against the inner wall of the tank. The inner diameter of the tank portion in contact with the single-layer perforated plate is defined as the inner diameter of the tank.

[0025] The plane of the single-layer perforated plate is perpendicular to the main axis of the tank body;

[0026] The single-layer perforated plate is uniformly provided with a number of vent holes, and the diameter of the vent holes is set to 1 / 8 to 1 / 16 of the inner diameter of the tank.

[0027] The turbulence-inducing component and the flow-guiding component are coaxially and sequentially arranged inside the tank. The gas entering the claw mixer passes through the turbulence-inducing component and the flow-guiding component in sequence and leads to the gas outlet.

[0028] Furthermore, the claw-type air inlet includes an air inlet pipe and a connecting part. The air inlet pipe includes several first claw-type air inlet pipes, several second claw-type air inlet pipes, and several third claw-type air inlet pipes, which are used to transport high-concentration exhaust gas, low-concentration exhaust gas, and fresh air, respectively.

[0029] The input ends of several first claw-type air intake pipes, several second claw-type air intake pipes, and several third claw-type air intake pipes extend in different directions away from the tank body and are arranged in a radial pattern.

[0030] The output end of the premix tank is connected to the first claw-type air inlet through the first claw-type air inlet pipe, the output end of the low-concentration exhaust gas blower is connected to the second claw-type air inlet through the second claw-type air inlet pipe, and the output end of the fresh air blower is connected to the third claw-type air inlet through the third claw-type air inlet pipe.

[0031] The connecting part is located at the connection between the tank body and the air inlet pipe. The first claw-type air inlet, the second claw-type air inlet and the third claw-type air inlet are all located on the connecting part to optimize gas distribution.

[0032] Furthermore, the connecting part is configured as a disc, and the connecting part is provided with through holes. The through holes are evenly distributed in the circumferential direction to form a double-ring structure, which are an inner ring area and an outer ring area, respectively.

[0033] The through hole includes a plurality of first through holes, a plurality of second through holes and a plurality of third through holes, wherein the first through holes are disposed in the inner ring area, forming the first claw-type air inlet, and are connected one-to-one with the first claw-type air inlet pipe;

[0034] The second through hole and the third through hole are alternately arranged in the outer ring area, forming the second claw-type air inlet and the third claw-type air inlet respectively, and are respectively connected to the second claw-type air inlet pipe and the third claw-type air inlet pipe.

[0035] Furthermore, the first claw-type air intake pipe, the second claw-type air intake pipe, and the third claw-type air intake pipe are evenly distributed circumferentially on the side of the connecting part away from the tank body, forming a double-ring structure corresponding to the position of the through hole on the connecting part.

[0036] Furthermore, the first claw-type air intake pipe, the second claw-type air intake pipe, and the third claw-type air intake pipe all include a first branch pipe and a second branch pipe;

[0037] The output end of the first branch pipe is connected to the input end of the second branch pipe, and the output end of the second branch pipe is connected to the tank body;

[0038] The first branch pipe is arranged parallel to the axial direction of the tank body, and the second branch pipe is at an angle of 30°-60° to the axial direction of the tank body, so that the gas enters the tank body along the angle.

[0039] Furthermore, the claw mixer also includes a vent valve, which is located at the top of the tank.

[0040] A control method for a claw-type explosion-proof mixing system for high and low concentration VOCs exhaust gases specifically includes the following:

[0041] Turn on the high-concentration exhaust gas fan and the low-concentration exhaust gas fan to introduce high-concentration exhaust gas and low-concentration exhaust gas. The high-concentration exhaust gas enters the premix tank for storage and buffering before being output. The control system turns on the fresh air fan and performs frequency conversion regulation according to the concentration and flow rate of the high-concentration exhaust gas and the low-concentration exhaust gas to control the fresh air volume and keep the concentration of the mixed gas within the set range.

[0042] Meanwhile, the control system adjusts the number of valves opened or closed according to the flow rates of high-concentration exhaust gas, low-concentration exhaust gas, and fresh air, so that the gas velocity entering the claw mixer through the claw inlet is maintained within the set range, ensuring the gas mixing effect.

[0043] The beneficial effects of this invention are:

[0044] This invention sets up a premixing tank as a pre-processing device in the mixing system. For pharmaceutical and other industries where high-concentration waste gas is greatly affected by production conditions and fluctuates significantly, the premixing tank acts as a buffer against fluctuating high-concentration waste gas. This ensures that the waste gas source is relatively stable at the same time and can effectively monitor the concentration of high-concentration waste gas. It also ensures that the high-concentration waste gas is fully mixed after being collected, thus providing support for subsequent mixing steps.

[0045] This invention optimizes the structure of the mixing equipment by replacing the traditional air inlet structure with a claw-type structure. This results in a more uniform distribution of air inlet points within the claw-type mixer. A multi-stage near-term mixing structure is also incorporated, along with turbulence-inducing and flow-guiding components within the mixer to increase the turbulence of the fluid. This ensures rapid and thorough mixing of high and low concentration waste gases from the moment they enter the mixer, preventing dead zones. Simultaneously, it accurately monitors waste gas concentrations for real-time and precise control. Through the unique claw-type structure design of the air inlet and the rationally arranged turbulence-inducing and flow-guiding devices within the tank, high and low concentration VOCs waste gases achieve thorough mixing in a short time, significantly improving mixing uniformity. This provides a stable mixed gas for subsequent waste gas purification, enhancing treatment efficiency and effectiveness.

[0046] This invention employs a precise control method for the entire high- and low-concentration waste gas mixing process. A high-concentration waste gas premixing tank is installed at the front end of the mixing system, equipped with gas concentration monitoring instruments and flow monitoring instruments. This buffers the concentration fluctuations of the high-concentration waste gas itself, monitors the high-concentration waste gas concentration, and adjusts the fresh air intake flow rate accordingly based on changes in gas parameters. This precisely controls the concentration of the mixed waste gas, preventing emergency shutdowns of the mixing system. The control system can automatically adjust the mixing parameters according to the actual operating conditions of the waste gas, achieving precise mixing of the waste gas, adapting to the treatment needs under different operating conditions, and improving the applicability and stability of the equipment.

[0047] This invention incorporates a control system and explosion relief valves within the mixing system to effectively prevent safety accidents caused by exhaust gas explosions during the mixing process, ensuring the safety of equipment and personnel. The mixing system features a reasonable overall structural design, compact layout, small footprint, and is easy to install and maintain, making it widely applicable to VOCs exhaust gas treatment in various industrial production scenarios.

[0048] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0049] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0050] The accompanying drawings are not drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures can be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings. The embodiments in the drawings do not constitute any limitation on the invention. Other drawings can be obtained by those skilled in the art based on the following figures without inventive effort:

[0051] Figure 1 This is a schematic diagram of a claw-type explosion-proof mixing system for high and low concentration VOCs waste gas in an embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of the claw mixer in an embodiment of the present invention;

[0053] Figure 3 This is a schematic diagram of the radial cross-section of the connecting part in an embodiment of the present invention;

[0054] Figure 4 This is a schematic diagram of the control principle of the high and low concentration VOCs waste gas claw-type explosion-proof mixing system in an embodiment of the present invention.

[0055] Attached image captions:

[0056] 1. Low-concentration exhaust gas fan; 11. Low-concentration gas storage tank; 2. High-concentration exhaust gas fan; 21. High-concentration gas storage tank; 22. Premixing tank; 3. Fresh air fan; 31. Fresh air source; 4. Valve; 5. Claw mixer; 51. Claw inlet; 52. Connecting part; 501. First branch pipeline; 502. Second branch pipeline; 511. First claw inlet pipeline; 512. Second claw inlet pipeline; 513. Third claw inlet pipeline; 521. First claw inlet; 522. Second claw inlet; 523. Third claw inlet; 53. Baffle assembly; 54. Flow guide assembly; 55. Explosion relief valve. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art.

[0058] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the features, wholes, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or sets thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0059] See attached document Figure 1 This embodiment provides a schematic diagram of a claw-type explosion-proof mixing system for high and low concentration VOCs exhaust gas, specifically including: a low concentration exhaust gas fan 1, a high concentration exhaust gas fan 2, a fresh air fan 3, a premix tank 22, a claw-type mixer 5, and a control system.

[0060] See attached document Figure 2 The claw mixer 5 includes a tank, a claw-shaped air inlet 51, an air outlet, a turbulence component 53, and a flow guiding component 54.

[0061] The claw-type air inlet 51 and the air outlet are respectively located at both ends of the tank body along the axial direction. The direction from the central axis of the claw-type air inlet 51 to the central axis of the air outlet is defined as the gas flow direction, and the axial direction of the tank body is set parallel to the gas flow direction.

[0062] The tank is coaxially arranged with at least one layer of turbulence-disrupting component 53 and at least one layer of flow-guiding component 54, with the planes of turbulence-disrupting component 53 and flow-guiding component 54 perpendicular to the gas flow direction.

[0063] The turbulence assembly 53 includes a fan-shaped swirl plate, specifically including an annular support frame and a rotating assembly with the axial direction parallel to the tank axis. The outer wall of the annular support frame abuts against the inner wall of the tank, and the rotating assembly is disposed inside the annular support frame.

[0064] The rotating assembly includes several arc-shaped blades and a rotating shaft located in the axial direction of the annular support frame. The arc-shaped blades are evenly distributed in the annular support frame along the radial direction of the rotating shaft, and the end of the arc-shaped blade away from the rotating shaft is connected to the inner wall of the annular support frame.

[0065] The number of curved blades is set to 8-16, depending on the exhaust gas volume.

[0066] The angle between the curved blade and the axis of rotation is 45°.

[0067] The flow guiding component 54 includes a single-layer orifice plate that abuts against the inner wall of the tank. The inner diameter of the tank portion in contact with the single-layer orifice plate is defined as the inner diameter of the tank.

[0068] The plane of the single-layer orifice plate is perpendicular to the main axis of the tank.

[0069] The single-layer perforated plate is evenly provided with several vent holes, and the diameter of the vent holes is set to 1 / 8 to 1 / 16 of the inner diameter of the tank. The specific vent hole diameter is adjusted according to the air volume of the mixed gas.

[0070] The gas entering the claw mixer 5 through the claw inlet 51 passes through the turbulence assembly 53 and the flow guide assembly 54 in sequence, and then leads to the outlet.

[0071] Preferably, the distance between the turbulence-disrupting component 53 near the tank input end and the tank input end is 1-2 times the inner diameter of the tank; the distance between the turbulence-disrupting component 53 and the flow-guiding component 54 near the turbulence-disrupting component 53 is 2-3 times the inner diameter of the tank; the distance between adjacent flow-guiding components 54 is 0.5-1 times the inner diameter of the tank; and the distance between the flow-guiding component 54 near the air outlet and the air outlet is 0.5-1 times the inner diameter of the tank.

[0072] The claw-type air inlet 51 includes several first claw-type air inlets 521, several second claw-type air inlets 522 and several third claw-type air inlets 523, which are used to transport high-concentration exhaust gas, low-concentration exhaust gas and fresh air, respectively.

[0073] The output end of the high-concentration exhaust gas blower 2 is connected to the input end of the premixing tank 22; the output end of the premixing tank 22 is connected to the input ends of several first claw-type air inlets 521 respectively; the output end of the low-concentration exhaust gas blower 1 is connected to the input ends of several second claw-type air inlets 522 respectively; the output end of the fresh air blower 3 is connected to the input ends of several third claw-type air inlets 523 respectively.

[0074] The premixing tank 22 includes an outer shell, an air inlet, and an air outlet. The air inlet is connected to the output end of the high-concentration exhaust gas blower 2, and the air outlet is connected to a plurality of first claw-type air inlets 521 for outputting high-concentration exhaust gas.

[0075] Specifically, the premixing tank 22, as a pre-mixing device in the mixing system, serves as a buffer for high-concentration exhaust gas. This prevents fluctuating high-concentration exhaust gas from impacting the mixing device at the downstream end of the system, thus avoiding slow system response. It ensures stable high-concentration exhaust gas concentrations within the same time period and facilitates better monitoring of high-concentration exhaust gas concentration and flow rate data. To ensure this, the premixing tank 22 has a large volume, designed to guarantee a residence time of at least 5 seconds for high-concentration exhaust gas within the tank.

[0076] The claw-type air inlet 51 includes an air inlet pipe and a connecting part 52. The air inlet pipe includes several first claw-type air inlet pipes 511, several second claw-type air inlet pipes 512 and several third claw-type air inlet pipes 513, which are used to transport high-concentration exhaust gas, low-concentration exhaust gas and fresh air, respectively.

[0077] The input ends of several first claw-type air intake pipes 511, several second claw-type air intake pipes 512 and several third claw-type air intake pipes 513 extend in different directions away from the tank body and form a radial distribution.

[0078] The connecting part 52 is located at the connection between the tank body and the air inlet pipe. The first claw-type air inlet 521, the second claw-type air inlet 522 and the third claw-type air inlet 523 are all located on the connecting part 52 to optimize gas distribution.

[0079] The output end of the premix tank 22 is connected to the first claw-type air inlet 521 through the first claw-type air inlet pipe 511, the output end of the low-concentration exhaust gas fan 1 is connected to the second claw-type air inlet 522 through the second claw-type air inlet pipe 512, and the output end of the fresh air fan 3 is connected to the third claw-type air inlet 523 through the third claw-type air inlet pipe 513.

[0080] The first claw-type air intake pipe 511, the second claw-type air intake pipe 512 and the third claw-type air intake pipe 513 are evenly distributed circumferentially on the side of the connecting part 52 away from the tank body, and form a double-ring structure corresponding to the position of the through hole on the connecting part 52.

[0081] See attached document Figure 3 The connecting part 52 is configured as a disc, and a through hole is provided on the connecting part 52. The through holes are evenly distributed in the circumference to form a double-ring structure, which consists of an inner ring area and an outer ring area.

[0082] The through hole includes several first through holes, several second through holes and several third through holes, wherein the first through holes are set in the inner ring area to form a first claw-type air inlet 521, which is connected to the first claw-type air inlet pipe 511 in a one-to-one correspondence.

[0083] The second and third through holes are arranged alternately in the outer ring area, forming the second claw-type air inlet 522 and the third claw-type air inlet 523 respectively, and are respectively connected to the second claw-type air inlet pipe 512 and the third claw-type air inlet pipe 513.

[0084] Preferably, the number of first claw-type air inlets 521 is set to 6, and the diameter of the claw opening is set to be controlled within 8-12 m / s according to the air inlet flow rate; the number of second claw-type air inlets 522 and third claw-type air inlets 523 is set to 6 each, and the diameter of the claw opening is set to be controlled within 10-20 m / s according to the air inlet flow rate.

[0085] The first claw-type intake pipe 511, the second claw-type intake pipe 512, and the third claw-type intake pipe 513 all include a first branch pipe 501 and a second branch pipe 502.

[0086] The output end of the first branch pipe 501 is connected to the input end of the second branch pipe 502, and the output end of the second branch pipe 502 is connected to the tank body. The first branch pipe 501 is arranged parallel to the axial direction of the tank body, and the second branch pipe 502 is at an angle of 30°-60° to the axial direction of the tank body, so that the gas enters the tank body along the angle.

[0087] Preferably, the second branch pipe 502 has an axial angle of 45° with the tank body.

[0088] In summary, the claw mixer 5 is equipped with a multi-stage gas mixing system, consisting of a claw inlet 51, a turbulence assembly 53, and a flow guiding assembly 54. The claw opening of the claw inlet 51 is welded at an angle, which allows the gas to be blown into the tank at a certain angle. This causes the gas to rotate in the cross-sectional direction of the tank, resulting in multiple airflows advancing in a spiral shape within the tank of the claw mixer 5. This allows the multiple airflows to interact fully to achieve thorough and rapid mixing.

[0089] During this process, the high-concentration exhaust gas flow is blown out from the inner ring of the claw-type air inlet 51, while the low-concentration and fresh air inlets are blown out alternately from the outer ring of the claw-type air inlet 51. This allows the low-concentration exhaust gas and fresh air to be initially mixed in the swirling flow, and then deeply mixed with the high-concentration exhaust gas, greatly improving the mixing effect and speed.

[0090] After the airflow passes through the claw-type air inlet 51 and is interactively mixed in the tank, it passes through at least one layer of turbulence component 53 and flow guide component 54 in sequence. The turbulence component 53 uses a fan-shaped swirl plate to turbulentize the airflow, increasing the turbulence of the fluid after the initial mixing of the gas, thereby achieving full mixing. The flow guide component 54 uses a single-layer perforated plate to turbulentize the mixed exhaust gas to a certain extent and distribute it evenly, so that the mixed gas is discharged stably and evenly.

[0091] When the claw-type air inlet 51 for transporting the same gas is turned on or off, a symmetrical arrangement is preferred. That is, the claw-type air inlet 51 that is symmetrical to the already turned on is turned on first, and the claw-type air inlet 51 that is not turned on in a symmetrical position is turned off first.

[0092] The high-concentration exhaust gas is stored in the high-concentration gas storage tank 21, which is connected to the high-concentration exhaust gas fan 2, and its output end is connected to the input end of the premixing tank 22.

[0093] Low-concentration exhaust gas is stored in a low-concentration gas storage tank 11, which is connected to a low-concentration exhaust gas fan 1; the fresh air fan 3 is connected to a fresh air source 31 to draw in fresh air from the air.

[0094] The output of the claw mixer 5 is connected to a pretreatment system or a gas combustion system, which are existing technologies and will not be described in detail here.

[0095] The control system includes a gas detection module and valve 4. The gas detection module includes a concentration detector and a flow transmitter. The concentration detector is located at the output end of the low-concentration exhaust gas fan 1, the premixing tank 22, and the claw mixer 5. The flow transmitter is located at the output end of the low-concentration exhaust gas fan 1, the high-concentration exhaust gas fan 2, and the fresh air fan 3. Valve 4 is located at the input end of the claw inlet 51 and is used to enable or disable the claw inlet 51.

[0096] The concentration detectors mentioned above are used to detect the concentration of passing gas in real time. Commercially available gas detectors or sensors can be used, including but not limited to photoionization detectors (PID), portable flame ionization detectors (FID), and lower limit combustible gas detectors (LEL).

[0097] The flow transmitters described above are used to detect the flow rate of gas in real time. Commercially available gas flow meters or sensors can be used, including but not limited to Rosemount 8732EM.

[0098] See attached document Figure 4 The control method for the hybrid system is as follows:

[0099] Turn on the high-concentration exhaust gas fan 2 and the low-concentration exhaust gas fan 1 to introduce high-concentration exhaust gas and low-concentration exhaust gas. The high-concentration exhaust gas enters the premix tank 22 for storage and buffering before being output. The control system turns on the fresh air fan 3 and performs frequency conversion regulation according to the concentration and flow rate of the high-concentration exhaust gas and low-concentration exhaust gas to control the fresh air volume and keep the concentration of the mixed gas within the set range.

[0100] Meanwhile, the control system adjusts the number of valves 4 that are opened or closed according to the flow rates of high-concentration exhaust gas, low-concentration exhaust gas, and fresh air, so that the gas velocity entering the claw mixer 5 through the claw air inlet 51 is maintained within the set range, ensuring the gas mixing effect.

[0101] Preferably, the air volume delivered by the high-concentration exhaust gas fan 2, the low-concentration exhaust gas fan 1, and the fresh air fan 3 can be adjusted within the range of 50% to 100% of the rated air volume of the fan.

[0102] Preferably, the concentration of the above-mentioned mixed gas is set within 25% of the lower explosive limit of VOCs, and the lower concentration limit is set according to the process requirements of the end-of-pipe waste gas treatment facility.

[0103] Preferably, the gas velocity entering the claw mixer 5 is set within the range of 8-12 m / s.

[0104] The specific mechanism of the above control method is as follows:

[0105] High-concentration VOCs waste gas is introduced into the claw mixer 5 through the first claw-type inlet pipe 511 and low-concentration VOCs waste gas through the second claw-type inlet pipe 512. The concentration detector and flow transmitter monitor the gas concentration and flow data in real time and transmit them to the control system. The control system calculates the amount of fresh air to be introduced based on the preset set range data.

[0106] Specifically, when the control system detects the concentration and air volume parameters of high-concentration exhaust gas and low-concentration exhaust gas, and determines that the mixed concentration is not lower than 25% of the lower explosive limit of VOCs, the fresh air fan 3 is turned on, and the fresh air fan 3 is frequency-controlled to precisely control the fresh air volume, so that the mixed gas concentration is maintained within a safe range of 25% below the lower explosive limit of VOCs.

[0107] Specifically, when the exhaust gas volume decreases or becomes unstable due to production reasons, resulting in a decrease in the exhaust gas concentration in the system, the fresh air volume is gradually reduced. Conversely, when the exhaust gas volume increases or fluctuates, resulting in an increase in the exhaust gas concentration in the system, the fresh air volume is increased.

[0108] When the control system detects the air volume parameters of high-concentration exhaust gas, low-concentration exhaust gas, and fresh air, and determines that the air velocity of any type of gas entering the claw-type air inlet 51 exceeds the set range, it controls the corresponding valve 4 of the claw-type air inlet 51 to open or close, so that the air velocity of the corresponding gas entering the claw-type air inlet 51 is maintained within the set range, ensuring the turbulence of the gas in the claw-type mixer 5, thereby ensuring the gas mixing effect.

[0109] Specifically, when the air volume of high-concentration or low-concentration exhaust gas decreases due to production reasons at the front end, the valve 4 corresponding to the claw-type air inlet 51 of some high-concentration or low-concentration exhaust gas is closed, reducing the number of claw-type air inlet pipes through which the corresponding gas passes, thereby increasing the air velocity of the corresponding gas through a single claw-type air inlet pipe; when the air volume of high-concentration or low-concentration exhaust gas increases, the valve 4 corresponding to the claw-type air inlet 51 of some high-concentration or low-concentration exhaust gas is opened, increasing the number of claw-type air inlet pipes through which the corresponding gas passes, thereby maintaining the air velocity of the corresponding gas through a single claw-type air inlet pipe within the set range.

[0110] When the control system adjusts the fresh air volume according to the concentration and volume of high-concentration and low-concentration exhaust gases, it opens an appropriate number of valves 4 corresponding to the third claw-type air inlets 523 according to the fresh air volume. When the fresh air volume is adjusted to be smaller, some valves 4 corresponding to the third claw-type air inlets 523 are closed, reducing the number of claw-type air inlets that the fresh air inlets pass through, thereby increasing the air velocity through a single claw-type air inlet. When the fresh air volume is adjusted to be larger, some valves 4 corresponding to the third claw-type air inlets 523 are opened, increasing the number of claw-type air inlets that the fresh air inlets pass through, thereby maintaining the air velocity through a single claw-type air inlet within the set range.

[0111] The formula for calculating the fresh air volume introduced based on the parameters of high-concentration and low-concentration exhaust gases is as follows:

[0112] in:

[0113] V3 – Required air volume for fresh air intake, in meters 3 / h;

[0114] V S —The set volume concentration, %vol; is the set range of the mixed gas concentration, which can be set according to actual needs, such as 20%-25% of the lower explosive limit of VOCs;

[0115] n i —The molar mass of pollutants in the exhaust gas, g / mol; can be calculated in advance or in real time based on the gas composition of the exhaust gas;

[0116] V i —Volume concentration of pollutants in exhaust gas, %vol;

[0117] P i —Lower explosive limit of pollutants in exhaust gas, %

[0118] V n —The molar volume of a gas under ideal conditions is 22.4 L / mol;

[0119] C1 — High concentration of exhaust gas, mg / m³ 3 ;

[0120] V1 – High-concentration exhaust gas volume, m 3 / h;

[0121] C2 – Concentration of low-concentration exhaust gas, mg / m³ 3 ;

[0122] V2 – Low-concentration exhaust gas volume, m 3 / h.

[0123] The control system calculates based on the above preset formulas and parameters and the real-time data from the gas detection module. Based on the results, it controls the fresh air fan 3 to adjust the amount of fresh air introduced.

[0124] The formula for calculating the number of valves 4 corresponding to the open claw inlet 51 based on the gas flow rate and the orifice diameter of the claw inlet 51 is as follows:

[0125]

[0126] in:

[0127] x — Number of valves 4 (high concentration / low concentration / fresh air) corresponding to the opened claw-type air inlet 51;

[0128] Q – Air intake flow rate (high concentration / low concentration / fresh air), m 3 / h;

[0129] v s —Set intake air velocity, m / s, setting range 2-8 m / s;

[0130] d——Inlet diameter, m.

[0131] The number of valves 4 opened corresponding to the first claw air inlet 521, the second claw air inlet 522, and the third claw air inlet 523 is calculated according to the above formula. The control system calculates based on the real-time data of the gas detection module according to the above preset formula and preset parameters, and controls the opening and closing of valves 4 according to the results. The number of valves 4 opened is the nearest integer up to the calculated result x.

[0132] Due to the unique claw-shaped structure design of the claw-type air inlet 51 and the rationally arranged turbulence-disrupting components 53 and flow-guiding components 54, rapid and efficient mixing of exhaust gas can be achieved within the claw-type mixer 5. When the internal pressure of the system exceeds the set threshold, the rupture membrane in the explosion relief valve 55 located at the top of the claw-type mixer 5 breaks, achieving instantaneous pressure relief and ensuring equipment safety. The uniformly mixed exhaust gas is discharged from the outlet of the claw-type mixer 5 at a stable concentration and enters the subsequent exhaust gas purification treatment equipment for further processing.

[0133] In summary, the control system controls the introduction of fresh air by interlocking the gas detection module and valve 4 in the system. While ensuring that the concentration of the mixed gas is maintained within a safe range, the system controls the flow rate of each gas through the claw mixer 5 and the corresponding valve 4 to ensure the gas mixing effect and further guarantee system safety.

[0134] Example 1

[0135] A claw-type explosion-proof mixing system for high and low concentration VOCs exhaust gases, the device used is as shown in the attached figure. Figure 1 As shown.

[0136] The volume of premixing tank 22 is set to 2.8 m³. 3 The residence time of high-concentration exhaust gas is 5 seconds.

[0137] The claw mixer 5 is equipped with one layer of turbulence-inducing component 53 and two layers of flow-guiding components 54, and the tank volume is 2.8 m³. 3 The distance between the turbulence-disrupting component 53 and the tank inlet is 1.3 m, the distance between the turbulence-disrupting component 53 and the first-stage flow guide component is 1.95 m, the distance between the first-stage flow guide component and the second-stage flow guide component is 0.65 m, and the distance between the flow guide component 54 and the air outlet is 0.4 m.

[0138] The turbulence component 53 uses arc-shaped blades, with 8 blades and a blade inclination angle of 45°; the flow guide component 54 uses a single-layer perforated plate with a perforation diameter of 60 mm.

[0139] The number of first claw-type air inlets 521 is set to 6, and the flow rate is controlled at 8-12 m / s; the number of second claw-type air inlets 522 and third claw-type air inlets 523 are alternately set, and the number of each is set to 6, with the flow rate controlled at 10-20 m / s.

[0140] The first claw-type air inlet 521 has a diameter of 100 mm and is evenly distributed circumferentially on the inner ring with a diameter of 250 mm. The second claw-type air inlet 522 and the third claw-type air inlet 523 have diameters of 90 mm and are evenly distributed circumferentially on the outer ring with a diameter of 520 mm.

[0141] The second branch pipe 502 has an axial angle of 45° with the tank body.

[0142] The air volume of the high-concentration exhaust gas fan 2 is set to 2000 m³ / s. 3 / h, the air volume delivered by low-concentration exhaust gas fan 1 is 4500m³ / h. 3 / h, the fresh air fan 3 delivers an air volume ranging from 500-2500 m³ / h. 3 / h.

[0143] The output of the claw mixer 5 is connected to the regenerative combustion device, which is a three-chamber RTO.

[0144] The gas detection module is model FID and mass flow controller, which can detect gas concentration and flow rate.

[0145] Hybrid system according to appendix Figure 4 The control method shown operates at normal temperature and pressure, with the concentration of high-concentration VOCs in the exhaust gas source ranging from 3000 to 10000 mg / m³. 3 The concentration of VOCs in the exhaust gas fluctuates within a certain range, with the concentration of low-concentration VOCs exhaust gas sources below 200 mg / m³. 3The concentration of the mixed gas after system treatment is 3000 mg / m³. 3 The entire system has been running stably for more than a week without any abnormalities, and the exhaust gas from the regenerative combustion device meets environmental protection requirements.

[0146] Example 2

[0147] A claw-type explosion-proof mixing system for high and low concentration VOCs exhaust gas.

[0148] The volume of the premixing tank 22 is set to 7m³. 3 The residence time of high-concentration exhaust gas is 5 seconds.

[0149] The claw mixer 5 is equipped with a flow-turbing component 53 and a flow-guiding component 54, and the tank volume is 3.9 m³. 3 The distance between the turbulence-disrupting component 53 and the tank inlet is 1.9 m, the distance between the turbulence-disrupting component 53 and the flow-guiding component 54 is 2.8 m, and the distance between the flow-guiding component 54 and the air outlet is 0.9 m.

[0150] The turbulence component 53 uses arc-shaped blades, with 8 blades and a blade inclination angle of 45°; the flow guide component 54 uses a single-layer perforated plate with a perforation diameter of 100 mm.

[0151] The number of first claw-type air inlets 521 is set to 6, and the flow rate is controlled at 8-12 m / s; the number of second claw-type air inlets 522 and third claw-type air inlets 523 are alternately set, and the number of each is set to 6, with the flow rate controlled at 10-20 m / s.

[0152] The first claw-type air inlet 521 has a diameter of 170 mm and is evenly distributed circumferentially on the inner ring with a diameter of 400 mm; the second claw-type air inlet 522 and the third claw-type air inlet 523 have a diameter of 140 mm and are evenly distributed circumferentially on the outer ring with a diameter of 750 mm.

[0153] The second branch pipe 502 has an axial angle of 45° with the tank body.

[0154] The high-concentration exhaust gas fan 2 is set to deliver an air volume of 5000 m³ / s. 3 / h, the air volume delivered by low-concentration exhaust gas fan 1 is 9000m³ / h. 3 / h, the fresh air fan 3 delivers an air volume ranging from 1000-4500 m³ / h. 3 / h.

[0155] The output of the claw mixer 5 is connected to the regenerative combustion device, which is a three-chamber RTO.

[0156] The gas detection module is model FID and mass flow controller, which can detect gas concentration and flow rate.

[0157] Hybrid system according to appendix Figure 4 The control method shown operates at normal temperature and pressure, with the concentration of high-concentration VOCs in the exhaust gas source ranging from 3000 to 12000 mg / m³. 3 The concentration of VOCs in the exhaust gas fluctuates within a certain range, with the concentration of low-concentration VOCs exhaust gas sources below 200 mg / m³. 3 The concentration of the mixed gas after system treatment is 3500 mg / m³. 3 The entire system has been running stably for more than a week without any abnormalities, and the exhaust gas from the regenerative combustion device meets environmental protection requirements.

[0158] Example 3

[0159] A claw-type explosion-proof mixing system for high and low concentration VOCs exhaust gas.

[0160] The volume of premixing tank 22 is set to 4.2 m³. 3 The residence time of high-concentration exhaust gas is 5 seconds.

[0161] The claw mixer 5 is equipped with a flow-turbing component 53 and a flow-guiding component 54, and the tank volume is 2.2 m³. 3 The distance between the turbulence component 53 and the tank inlet is 1.5 m, the distance between the turbulence component 53 and the flow guide component 54 is 2.3 m, and the distance between the flow guide component 54 and the air outlet is 0.8 m.

[0162] The turbulence component 53 uses arc-shaped blades, with 8 blades and a blade inclination angle of 45°; the flow guide component 54 uses a single-layer perforated plate with a perforation diameter of 80 mm.

[0163] The number of first claw-type air inlets 521 is set to 6, and the flow rate is controlled at 8-12 m / s; the number of second claw-type air inlets 522 and third claw-type air inlets 523 are alternately set, and the number of each is set to 6, with the flow rate controlled at 10-20 m / s.

[0164] The first claw-type air inlet 521 has a diameter of 130 mm and is evenly distributed circumferentially on the inner ring with a diameter of 300 mm; the second claw-type air inlet 522 and the third claw-type air inlet 523 have a diameter of 100 mm and are evenly distributed circumferentially on the outer ring with a diameter of 600 mm.

[0165] The second branch pipe 502 has an axial angle of 45° with the tank body.

[0166] The air volume of the high-concentration exhaust gas fan 2 is set to 3000 m³ / s. 3 / h, the air volume delivered by low-concentration exhaust gas fan 1 is 6000m³ / h. 3 / h, the fresh air fan 3 delivers an air volume ranging from 1000-3000 m³ / h. 3 / h.

[0167] The output of the claw mixer 5 is connected to the regenerative combustion device, which is a three-chamber RTO.

[0168] The gas detection module is model FID and mass flow controller, which can detect gas concentration and flow rate.

[0169] Hybrid system according to appendix Figure 4 The control method shown operates at normal temperature and pressure, with the concentration of high-concentration VOCs in the exhaust gas source ranging from 2000 to 15000 mg / m³. 3 The concentration of VOCs in the exhaust gas fluctuates within a certain range, with the concentration of low-concentration VOCs exhaust gas sources below 200 mg / m³. 3 The concentration of the mixed gas after system treatment is 3200 mg / m³. 3 The entire system has been running stably for more than a week without any abnormalities, and the exhaust gas from the regenerative combustion device meets environmental protection requirements.

[0170] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

[0171] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. Technical details not described in detail in this invention can all be implemented using any existing technology in the art. In particular, all technical features not described in detail in this invention can be implemented using any existing technology.

Claims

1. A claw-type explosion-proof mixing system for high and low concentration VOCs exhaust gas, characterized in that, The mixing system includes a low-concentration exhaust gas fan, a high-concentration exhaust gas fan, a fresh air fan, a premixing tank, a claw mixer, and a control system. The claw mixer includes a tank, an air inlet and an air outlet, with the air inlet and the air outlet respectively located at both ends of the axial direction of the tank, and the air inlet being configured as a claw-type air inlet. The claw-shaped air inlet includes several first claw-shaped air inlets, several second claw-shaped air inlets, and several third claw-shaped air inlets; The output end of the high-concentration exhaust gas blower is connected to the input end of the premixing tank; the output end of the premixing tank is respectively connected to a plurality of first claw-type air inlet input ends; the output end of the low-concentration exhaust gas blower is respectively connected to a plurality of second claw-type air inlet input ends; the output end of the fresh air blower is respectively connected to a plurality of third claw-type air inlet input ends. The control system includes a gas detection module and valves; The gas detection module is installed at least at the output end of the low-concentration exhaust gas fan, the high-concentration exhaust gas fan, the fresh air fan, the premix tank, and the claw mixer, and is used to detect gas parameters. The valve is located at the input end of the claw-type air inlet and is used to enable or disable the claw-type air inlet. The claw-shaped air inlet includes an air inlet pipe and a connecting part. The air inlet pipe includes several first claw-shaped air inlet pipes, several second claw-shaped air inlet pipes and several third claw-shaped air inlet pipes, which are used to transport high-concentration exhaust gas, low-concentration exhaust gas and fresh air, respectively. The input ends of several first claw-type air intake pipes, several second claw-type air intake pipes, and several third claw-type air intake pipes extend in different directions away from the tank body and are arranged in a radial pattern. The connecting part is located at the connection between the tank body and the air inlet pipe. The connecting part is disc-shaped and has through holes. The through holes are evenly distributed in the circumferential direction to form a double-ring structure, which consists of an inner ring area and an outer ring area. The through hole includes a plurality of first through holes, a plurality of second through holes and a plurality of third through holes, wherein the first through holes are disposed in the inner ring area, forming the first claw-type air inlet, and are connected one-to-one with the first claw-type air inlet pipe; The second through hole and the third through hole are alternately arranged in the outer ring area, forming the second claw-type air inlet and the third claw-type air inlet respectively, and are respectively connected to the second claw-type air inlet pipe and the third claw-type air inlet pipe.

2. The high and low concentration VOCs exhaust gas claw-type explosion-proof mixing system according to claim 1, characterized in that, The high-concentration exhaust gas delivered by the high-concentration exhaust gas fan enters the premixing tank, where it mixes with the low-concentration exhaust gas delivered by the low-concentration exhaust gas fan and / or the fresh air delivered by the fresh air fan through the claw-type air inlet into the claw mixer. The control system acquires gas parameters through the gas detection module, performs frequency conversion control on the fresh air fan according to the changes in gas parameters, and simultaneously controls the valve to keep the concentration and flow rate of the mixed gas within a set range, thereby achieving control of the mixing system.

3. The high and low concentration VOCs exhaust gas claw-type explosion-proof mixing system according to claim 1, characterized in that, The gas detection module includes a concentration detector and a flow transmitter. The concentration detector is installed at least at the output end of the low-concentration exhaust gas fan, the premixing tank, and the claw mixer. The flow transmitter is installed at least at the output end of the low-concentration exhaust gas fan, the high-concentration exhaust gas fan, and the fresh air fan.

4. The high and low concentration VOCs exhaust gas claw-type explosion-proof mixing system according to claim 1, characterized in that, The claw mixer also includes at least one layer of turbulence-disrupting components; The turbulence-inducing component includes a fan-shaped swirl plate, specifically including an annular support frame and a rotating component with the axial direction parallel to the tank axis. The outer wall of the annular support frame abuts against the inner wall of the tank, and the rotating component is disposed inside the annular support frame. The rotating assembly includes several arc-shaped blades and a rotating shaft located in the axial direction of the annular support frame. The arc-shaped blades are evenly distributed in the annular support frame along the radial direction of the rotating shaft, and one end of the arc-shaped blade away from the rotating shaft is connected to the inner wall surface of the annular support frame. The number of arc-shaped blades is set to 8-16, and the angle between the arc-shaped blades and the rotation axis is 45°.

5. The high and low concentration VOCs exhaust gas claw-type explosion-proof mixing system according to claim 4, characterized in that, The claw mixer also includes at least one flow guiding component; The flow guiding component includes a single-layer perforated plate, which abuts against the inner wall of the tank. The inner diameter of the tank portion in contact with the single-layer perforated plate is defined as the inner diameter of the tank. The plane of the single-layer perforated plate is perpendicular to the main axis of the tank body; The single-layer perforated plate is uniformly provided with a number of vent holes, and the diameter of the vent holes is set to 1 / 8 to 1 / 16 of the inner diameter of the tank. The turbulence-inducing component and the flow-guiding component are coaxially and sequentially arranged inside the tank. The gas entering the claw mixer passes through the turbulence-inducing component and the flow-guiding component in sequence and leads to the gas outlet.

6. The high and low concentration VOCs exhaust gas claw-type explosion-proof mixing system according to claim 1, characterized in that, The output end of the premix tank is connected to the first claw-type air inlet through the first claw-type air inlet pipe, the output end of the low-concentration exhaust gas blower is connected to the second claw-type air inlet through the second claw-type air inlet pipe, and the output end of the fresh air blower is connected to the third claw-type air inlet through the third claw-type air inlet pipe. The first claw-type air inlet, the second claw-type air inlet, and the third claw-type air inlet are all disposed on the connecting part to optimize gas distribution.

7. The high and low concentration VOCs exhaust gas claw-type explosion-proof mixing system according to claim 1, characterized in that, The first claw-type air intake pipe, the second claw-type air intake pipe, and the third claw-type air intake pipe are evenly distributed circumferentially on the side of the connecting part away from the tank body, forming a double-ring structure corresponding to the position of the through hole on the connecting part.

8. The high and low concentration VOCs exhaust gas claw-type explosion-proof mixing system according to claim 1, characterized in that, The first claw-type air intake pipe, the second claw-type air intake pipe, and the third claw-type air intake pipe all include a first branch pipe and a second branch pipe; The output end of the first branch pipe is connected to the input end of the second branch pipe, and the output end of the second branch pipe is connected to the tank body; The first branch pipe is arranged parallel to the axial direction of the tank body, and the second branch pipe is at an angle of 30°-60° to the axial direction of the tank body, so that the gas enters the tank body along the angle.

9. The high and low concentration VOCs exhaust gas claw-type explosion-proof mixing system according to claim 1, characterized in that, The claw mixer also includes a vent valve, which is located at the top of the tank.

10. A control method for a high- and low-concentration VOCs exhaust gas claw-type explosion-proof mixing system as described in any one of claims 1-9, characterized in that, The control method includes the following: Turn on the high-concentration exhaust gas fan and the low-concentration exhaust gas fan to introduce high-concentration exhaust gas and low-concentration exhaust gas. The high-concentration exhaust gas enters the premix tank for storage and buffering before being output. The control system turns on the fresh air fan and performs frequency conversion regulation according to the concentration and flow rate of the high-concentration exhaust gas and the low-concentration exhaust gas to control the fresh air volume and keep the concentration of the mixed gas within the set range. Meanwhile, the control system adjusts the number of valves opened or closed according to the flow rates of high-concentration exhaust gas, low-concentration exhaust gas, and fresh air, so that the gas velocity entering the claw mixer through the claw air inlet is maintained within the set range, ensuring the gas mixing effect.

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