Tail gas treatment method and equipment based on CVD (chemical vapor deposition) coating process

Abstract

The tail gas treatment method based on the CVD coating technology comprises the steps that tail gas flow data in a tail gas pipeline are obtained, and the flow speed of the tail gas pipeline is adjusted according to the difference value between the tail gas flow data and the target flow speed; acquiring temperature data of two opposite ends of the tail gas pipeline, and adjusting the temperature of the two opposite ends in the tail gas pipeline according to a difference value between the temperature data and a preset temperature; a scaling state value in the tail gas pipeline is obtained, and if the scaling state value is larger than a preset threshold value, nitrogen is introduced into the tail gas pipeline; the pressure value in the tail gas pipeline is obtained, the introduction amount and introduction time of nitrogen are adjusted according to the pressure value, and the tail gas treatment process is completed. By comprehensively regulating and controlling the flow speed, the temperature, the scaling state and the pressure in the tail gas pipeline, the adaptability of the tail gas treatment system to complex working conditions is improved, and the problems of low treatment efficiency and high maintenance cost caused by pipeline layout limitation, damage of a high-temperature heat tracing band, increase of maintenance difficulty of heat preservation cotton and scaling in the prior art are solved.

Description

Technical Field

[0001] This application relates to the field of exhaust gas treatment technology, and in particular to an exhaust gas treatment method and equipment based on CVD coating process. Background Technology

[0002] Chemical vapor deposition (CVD) is a thin-film deposition technology used in industries such as semiconductors, photovoltaic devices, and functional coatings. However, the exhaust gases produced by CVD processes contain volatile organic compounds, particulate matter, and unreacted chemicals. Direct emission without effective treatment poses a threat to the environment and human health. In practical applications, existing exhaust gas treatment technologies generally suffer from a core problem: insufficient adaptability of exhaust gas treatment systems to the complex operating conditions within pipelines.

[0003] In CVD exhaust gas treatment, the actual layout of exhaust gas pipelines is often constrained by the space of process equipment and production site, and some pipeline locations are not suitable for frequent disassembly and maintenance. To prevent exhaust gas from condensing or scaling inside the pipelines, it is usually necessary to wrap the pipelines with heat tracing tape to maintain the pipeline temperature. However, heat tracing tape is easily damaged due to heat loss or localized overheating in high-temperature environments, especially in high-temperature areas near the gas outlet of the reaction chamber, where the service life of the heat tracing tape is significantly shortened. To reduce heat loss, existing technologies often add insulation cotton to the outside of the heat tracing tape, which further increases the difficulty of pipeline disassembly and maintenance, and also exacerbates the scaling problem at the connection between the pipeline and subsequent treatment equipment (such as spray towers).

[0004] Therefore, there is an urgent need for an exhaust gas treatment method that can fully adapt to complex operating conditions in order to improve the system's operating efficiency and ease of maintenance. Summary of the Invention

[0005] The purpose of this application is to provide a method and equipment for exhaust gas treatment based on CVD coating technology, solving the technical problem of insufficient adaptability to complex working conditions in existing technologies. To achieve this objective, this application adopts the following technical solution: A method for treating exhaust gas based on CVD coating process, comprising: The exhaust gas pipeline is connected to a chemical vapor deposition device to obtain exhaust gas flow data in the exhaust gas pipeline, and the flow rate of the exhaust gas pipeline is adjusted according to the difference between the exhaust gas flow data and the target flow rate. Acquire temperature data at opposite ends of the exhaust pipe, and adjust the temperature at opposite ends of the exhaust pipe based on the difference between the temperature data and a preset temperature; Obtain the scaling status value inside the exhaust pipe; if the scaling status value is greater than a preset threshold, introduce nitrogen into the exhaust pipe. The pressure value inside the exhaust gas pipeline is obtained, and the nitrogen flow rate and flow time are adjusted according to the pressure value to complete the exhaust gas treatment process.

[0006] Further, the step of connecting the exhaust gas pipeline to the chemical vapor deposition equipment, acquiring exhaust gas flow rate data within the exhaust gas pipeline, and adjusting the flow rate of the exhaust gas pipeline based on the difference between the exhaust gas flow rate data and the target flow rate includes: The exhaust gas pipeline is connected to the exhaust gas outlet of the chemical vapor deposition equipment, and the flow distribution data in the exhaust gas pipeline is collected based on the flow sensor in the exhaust gas pipeline. The actual flow velocity at each cross section of the pipe is calculated based on the flow distribution data and the cross-sectional area parameters of the exhaust pipe, thus obtaining actual flow velocity distribution data that includes the spatial distribution and temporal variation of the flow velocity. The velocity deviation value of each section in the exhaust gas pipeline is calculated based on the difference between the actual velocity distribution data and the preset target velocity. The multiple velocity deviation values ​​are then weighted and averaged according to the changing trend of the flow distribution data to obtain the velocity deviation parameter. The operating power of the vacuum pump is controlled according to the flow rate deviation parameter to adjust the flow rate in the exhaust gas duct, wherein the vacuum pump is connected to both the exhaust gas duct and the chemical vapor deposition equipment.

[0007] Further, the step of acquiring temperature data at opposite ends of the exhaust pipe and adjusting the temperature at opposite ends of the exhaust pipe based on the difference between the temperature data and a preset temperature includes: Based on the temperature sensors at the inlet and outlet ends of the exhaust pipe, the real-time temperature of the airflow at both ends of the exhaust pipe is collected to obtain initial temperature distribution data including the temperature changes of the inlet and outlet ends over time. The initial temperature distribution data is compared point by point with the preset target temperature to obtain the temperature deviation data between the inlet and outlet temperatures. The temperature control device of the exhaust pipe is dynamically adjusted according to the temperature deviation parameter to obtain a heat exchange control signal. The heat compensation values ​​at both ends of the exhaust pipe are obtained based on the temperature deviation distribution parameters, and the heat transfer medium is preheated through the heating chamber based on the heat compensation values. The heat-conducting medium is transported to the output mixing chamber and dynamically mixed with the low-temperature heat-conducting medium stored in the room temperature chamber to obtain the target temperature medium. The target temperature medium is transported to the heat exchange area corresponding to the exhaust gas pipe, so that the temperature at both ends of the exhaust gas pipe reaches the preset temperature range.

[0008] Furthermore, the step of obtaining the scaling status value inside the exhaust gas pipe includes: Based on the multi-point ultrasonic sensor array inside the exhaust pipe, ultrasonic signals are emitted to the inner wall of the pipe, and the sound wave signals reflected back from the inner wall of the pipe are received to obtain initial sound wave reflection data. The initial sound wave reflection data includes the sound wave propagation time difference at different time points of multiple sampling points. The scale thickness at each sampling point on the inner wall of the exhaust pipe is calculated based on the initial acoustic wave reflection data, and scale thickness distribution data is generated. By comparing the thickness changes of the same sampling point at different time points in the scale thickness distribution data, the thickness change values ​​of multiple sampling points are integrated and analyzed to obtain a scale state value that represents the overall scale degree.

[0009] Further, the step of introducing nitrogen gas into the exhaust gas pipe if the scaling condition value is greater than a preset threshold includes: The scaling state value is compared with a preset threshold using a comparator circuit to generate a trigger signal for controlling nitrogen gas. The trigger signal is high when the scaling state value exceeds the preset threshold and low when it does not exceed the preset threshold. Nitrogen gas is controlled to enter the exhaust gas pipeline through the gas transmission pipeline, so that the nitrogen gas is distributed in the scale area on the inner wall of the exhaust gas pipeline, forming a nitrogen protective atmosphere covering the exhaust gas pipeline.

[0010] Further, the step of obtaining the pressure value inside the exhaust gas pipe and adjusting the nitrogen flow rate and flow time based on the pressure value includes: The pressure value of the airflow inside the exhaust pipe is obtained by the pressure sensor on the inner wall of the exhaust pipe, and the initial pressure distribution data is obtained. Extract the maximum fluctuation rate and maximum decrease rate of the pressure value at each sampling point in the initial pressure distribution data to obtain the pressure fluctuation parameters; Based on the comparison between the pressure fluctuation parameter and the preset pressure fluctuation threshold, an initial adjustment coefficient for the nitrogen injection rate is obtained; wherein, when the pressure fluctuation parameter exceeds the preset pressure fluctuation threshold, the initial adjustment coefficient is increased, and when the pressure fluctuation parameter is lower than the preset pressure fluctuation threshold, the initial adjustment coefficient is decreased. Based on the product of the initial adjustment coefficient and the real-time pressure value in the exhaust gas pipeline, the adjustment value of the nitrogen inlet is calculated, and the nitrogen inlet time is calculated according to the duration of the pressure fluctuation parameter to form the adjustment parameter; The operating status of the nitrogen supply device is controlled according to the adjustment parameters. The nitrogen supply device is connected to the inlet of the exhaust gas pipeline through a solenoid valve, and the opening degree of the solenoid valve is adjusted according to the adjustment value of the nitrogen flow rate.

[0011] This application also discloses an exhaust gas treatment device, applied to the exhaust gas treatment method based on CVD coating process described in any of the above claims, comprising: An exhaust gas duct is used to transport exhaust gas to be treated. The exhaust gas duct is equipped with a temperature sensor, an ultrasonic sensor, a pressure sensor and a flow sensor. A vacuum pump is provided, and a check valve is provided at the outlet of the exhaust gas pipeline. One end of the vacuum pump is connected to the outlet of the chemical vapor deposition equipment, and the other end is connected to the inlet of the exhaust gas pipeline through the check valve. A temperature control device, which is connected to the exhaust pipe, is used to adjust the temperature at opposite ends of the exhaust pipe. The control unit is electrically connected to the flow sensor, temperature sensor, ultrasonic sensor, pressure sensor, vacuum pump, and temperature control device, respectively. It is used to receive data collected by each sensor, process it, generate control signals, control the operating status of each device, and complete the exhaust gas treatment process.

[0012] Furthermore, it also includes a double-layer sandwich, which comprises a temperature-controlled sandwich and a heat-insulating layer, which are sequentially disposed on the outer wall of the exhaust gas pipe; wherein, the temperature-controlled sandwich is filled with a heat-conducting medium with adjustable temperature, and the temperature of the heat-conducting medium is regulated by connecting it to the temperature control device.

[0013] Furthermore, the exhaust pipe has a straight cylindrical structure, and the exhaust pipe is inclined at an angle of 0.17 to 0.5 relative to the outlet of the chemical vapor deposition equipment along the axial direction.

[0014] Furthermore, the temperature control device includes a heating chamber, a mixing chamber, a cooling chamber, and a heat transfer medium conveying pipeline. The heating chamber is used to preheat the heat transfer medium. The mixing chamber is used to dynamically mix the preheated heat transfer medium with a room temperature heat transfer medium in a proportional manner to obtain a medium at the target temperature. The cooling chamber is used to cool the heat transfer medium. The heat transfer medium conveying pipeline is responsible for conveying the heat transfer medium processed by the heating chamber, the mixing chamber, and the cooling chamber to the heat exchange area corresponding to the exhaust gas pipeline.

[0015] Compared with the prior art, this application has the following beneficial effects: This application discloses a tail gas treatment method and equipment based on CVD coating technology. By acquiring tail gas flow data in real time and dynamically adjusting the flow rate, it avoids deposition or blockage caused by improper flow rate. By monitoring the temperature at both ends of the pipeline and precisely adjusting the temperature distribution, it effectively prevents pipe scaling and shortened lifespan of the heating cable caused by localized overheating or condensation. By detecting the scaling status and introducing nitrogen when necessary, it prevents the accumulation of flammable and explosive scaling residues that could lead to safety accidents, while also reducing the problems of increased pipeline pressure drop and decreased heat exchange efficiency caused by scaling. Furthermore, by using a pressure sensor to monitor pressure changes within the pipeline in real time, it promptly adjusts the treatment parameters when the pressure is abnormal, ensuring operation within a safe pressure range and improving the adaptability of the tail gas treatment system to complex operating conditions. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0018] Figure 1 This is a schematic diagram of the overall steps of an exhaust gas treatment method based on CVD coating technology.

[0019] Figure 2 This is a schematic diagram of the overall structure of an exhaust gas treatment device. Figure 3 A schematic diagram of the exhaust gas pipeline according to an embodiment of an exhaust gas treatment device; Figure 4 This is a schematic diagram of the structure of a temperature control device according to an embodiment of an exhaust gas treatment equipment.

[0020] The attached figures are labeled as follows: 1. Exhaust gas duct; 11. Temperature control jacket; 12. Insulation layer; 2. Vacuum pump; 3. Temperature control device; 31. Heating chamber; 32. Mixing chamber; 33. Cooling chamber; 34. Compressor; 35. Delivery pipeline; 36. Liquid level sensor; 4. Chemical vapor deposition equipment; 5. Temperature sensor; 6. Flange. Detailed Implementation

[0021] To make the inventive objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component centrally located at the same time.

[0023] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] refer to Figure 1 This application provides a method for exhaust gas treatment based on CVD coating process, comprising: S1: Connect the exhaust gas pipeline to the chemical vapor deposition equipment, obtain the exhaust gas flow rate data in the exhaust gas pipeline, and adjust the flow rate of the exhaust gas pipeline according to the difference between the exhaust gas flow rate data and the target flow rate. In step S1, the exhaust gas pipeline is connected to the chemical vapor deposition (CVD) equipment. During operation, the CVD equipment generates exhaust gas containing volatile organic compounds, particulate matter, and unreacted chemicals. This exhaust gas is discharged from the reaction chamber through a dedicated exhaust gas pipeline, allowing it to enter subsequent treatment equipment (such as a spray tower or adsorption unit). Flange connections or sealed joints can be used to prevent leakage. After connection, a stable exhaust gas flow is formed within the exhaust gas pipeline, and the exhaust gas flow rate data is acquired in real time using a flow sensor. The flow sensor can be a mass flow meter or a differential pressure flow meter; the specific model is determined based on the pipe diameter and exhaust gas composition. After acquiring the exhaust gas flow rate data, a target flow rate is set. The target flow rate is set based on the specific requirements of the CVD process and the physical characteristics of the pipe. Assuming the pipe inner diameter is D (unit: m), the target flow rate v... target (Unit: m / s) can be initially determined using the following formula: v target = Q target / A, where Q target Target volumetric flow rate (unit: m³) 3 / s), where A is the cross-sectional area of ​​the pipe, A = π * (D / 2) 2 For example, suppose a certain CVD process requires an exhaust gas volumetric flow rate of 0.01 m³ / s. 3 / s, the pipe's inner diameter is 0.05 m, and the cross-sectional area A = π * (0.05 / 2) 2 ≈ 0.001963 m 2 Then the target flow velocity v target = 0.01 / 0.001963 ≈ 5.1 m / s. In actual operation, the exhaust gas velocity v is measured in real time. actual With the target flow velocity v target There may be a difference Δv between them, which can be calculated using the formula: Δv = v actual -v target To eliminate this difference, the opening degree of the vacuum pump can be controlled. Based on the sign and magnitude of Δv, a corresponding control signal is output to make the actual flow rate gradually approach the target flow rate.

[0025] S2: Obtain temperature data at both ends of the exhaust pipe, and adjust the temperature at both ends of the exhaust pipe according to the difference between the temperature data and the preset temperature; In step S2, after the exhaust gas pipeline is connected to the CVD equipment, the inlet end is close to the CVD reaction chamber, and the outlet end is connected to subsequent treatment equipment (such as an exhaust gas scrubbing tower or adsorption device). Temperature sensors, such as thermocouples or infrared thermometers, are installed at both the inlet and outlet ends of the pipeline. The preset temperature is determined comprehensively based on the chemical composition of the exhaust gas in the CVD process, the temperature resistance of the pipeline material, and the operating requirements of the subsequent treatment equipment. CVD exhaust gas contains volatile organic compounds, unreacted precursor gases (such as silanes or silicon tetrachloride), and particulate matter. If the pipeline temperature is too low, some components in the exhaust gas may condense, leading to deposits on the inner wall of the pipeline; if the temperature is too high, it may accelerate the aging of the pipeline material or increase energy consumption. Therefore, the preset temperature needs to ensure that the exhaust gas remains in a gaseous state while avoiding damage to the pipeline or equipment. The determination of the preset temperature is based on experimental data and process experience. For example, for exhaust gas containing silanes, its condensation point is low, but to prevent deposits inside the pipeline, the preset temperature at the inlet end is set higher than the saturated vapor temperature of the main components of the exhaust gas, while also considering the operating temperature of the reaction chamber. The preset temperature at the outlet is set according to the requirements of subsequent treatment equipment. For example, a tail gas scrubbing tower requires an inlet temperature of around 180°C to optimize the scrubbing effect, so the preset outlet temperature is set to 180°C. After obtaining the actual temperature data and the preset temperature, the difference between the two temperatures is calculated. The inlet temperature difference is obtained by subtracting the preset inlet temperature from the measured inlet temperature, and the outlet temperature difference is calculated by subtracting the preset outlet temperature from the measured outlet temperature. If the difference is negative, it means the actual temperature is lower than the preset temperature, and the pipe temperature needs to be increased by heating equipment; if the difference is positive, it means the actual temperature is higher than the preset temperature, and the temperature needs to be reduced by cooling equipment. The temperature adjustment process is completed by the control system, which adopts a proportional-integral-derivative (PID) control strategy to ensure that the temperature quickly stabilizes near the preset value. During the adjustment process, the sensor continuously monitors the temperature change, and the control system dynamically adjusts the output according to the real-time difference until the temperature difference approaches zero.

[0026] S3: Obtain the scaling status value inside the exhaust pipe; if the scaling status value is greater than a preset threshold, introduce nitrogen into the exhaust pipe. In step S3, the exhaust gas generated by the CVD process contains volatile organic compounds, unreacted precursor gases (such as silanes and silicon tetrachloride), and solid particulate matter. These substances deposit within the pipeline due to changes in temperature, pressure, or flow rate, forming scale. Ultrasonic sensors, laser thickness gauges, or infrared thermal imaging devices are installed within the exhaust gas pipeline to detect the physical properties of the pipeline's inner wall using non-contact or contact methods. For example, an ultrasonic sensor can estimate the thickness of the scale on the pipeline's inner wall by emitting ultrasonic waves and receiving the time difference between the reflected waves, obtaining a thickness value, such as 2 mm of deposit thickness per square meter of inner wall. This thickness value represents the scale state. The obtained scale state value is compared with a preset threshold to determine whether nitrogen gas needs to be introduced. The preset threshold is set by comprehensively considering the pipeline material, exhaust gas composition, operating environment, and safety requirements. In actual industrial scenarios, the preset threshold can be determined based on experimental data and historical operating experience. For example, assuming experiments prove that when the scale thickness inside a pipe exceeds 3 mm, flammable components in the deposits (such as hydrocarbons) may react with oxygen at high temperatures, posing a risk of deflagration, a preset threshold can be set at 2.5 mm to allow for a certain safety margin. This threshold can be used to test scale thicknesses on simulated pipes and record the relationship between thickness and reaction risk. In actual operation, when the scale condition value exceeds the preset threshold, nitrogen gas will be introduced into the exhaust gas pipe. Nitrogen, as an inert gas, can effectively isolate the scale residue inside the pipe from contact with oxygen, thereby reducing the risk of reaction between flammable and explosive substances. In another embodiment, two parallel exhaust gas pipes are provided, one of which is in operation and the other is a backup pipe. When the scale condition value of the operating pipe exceeds the preset threshold, the system automatically switches to the backup pipe, while simultaneously introducing nitrogen gas into the heavily scaled operating pipe for protection. In this step, nitrogen is introduced through an automated control system, such as a solenoid valve controlling the connection between the nitrogen tank and the pipeline. Nitrogen is introduced into the pipeline at a constant flow rate (e.g., 100 liters per minute), continuously flushing the inner wall of the pipeline to ensure complete replacement of oxygen. Assuming the main pipeline has a volume of 500 liters, the nitrogen introduction time can be set to 10 minutes to ensure that the oxygen concentration in the pipeline drops below a safe level (e.g., below 2%).

[0027] S4: Obtain the pressure value inside the exhaust gas pipeline, and adjust the nitrogen flow rate and flow time according to the pressure value to complete the exhaust gas treatment process.

[0028] In step S4, the pressure value inside the exhaust pipe is obtained by measuring it in real time using a pressure sensor installed in the pipe. The sensor can be a piezoresistive or capacitive device, which can capture minute changes from a few Pascals to several hundred Pascals when the gas flows in the pipe. This pressure value is obtained because after nitrogen is introduced in step S3, the gas mixture in the pipe will change dynamically. If the pressure is too high, it may cause the pipe to expand or leak. If it is too low, it means that the nitrogen is not diluted enough and cannot effectively isolate oxygen. The nitrogen flow rate and timing are adjusted based on this pressure value. The flow rate refers to the degree of opening of the nitrogen valve, controlled by a solenoid valve or proportional valve. The initial flow rate is roughly set based on the scaling condition value of S3. For example, if the scaling condition value just exceeds the preset threshold, the initial flow rate may be set to 10% of the pipe volume per minute. After obtaining the pressure value, if the actual pressure is higher than a preset safety upper limit, such as 1.5 times the atmospheric pressure, this upper limit is an empirical value derived from the pipe pressure resistance test data of the CVD equipment manufacturer, designed to prevent pipe deformation. The flow rate is automatically reduced, for example, from the initial 5 liters per minute to 3 liters per minute, by gradually closing the valve to release excess pressure until the pressure stabilizes within the target range. This target range is set according to the nominal working pressure of the exhaust pipe, usually 0.8 to 1.2 times the atmospheric pressure, and is determined in the design phase through laboratory experiments simulating gas flow, so that the nitrogen can fully dilute flammable residues and not cause system overload. If the pressure rises rapidly during the nitrogen inlet process, it indicates that local turbulence has been generated when the residual gas in the pipeline is pushed by nitrogen. The inlet time needs to be extended to smooth out this process. For example, the initial inlet time may be set to 30 seconds, but if the pressure reaches the preset upper limit at 15 seconds, it should be automatically extended to 45 seconds or even longer. The process should be gradually balanced by continuously introducing nitrogen at a low flow rate to ensure that the nitrogen has enough time to penetrate into every corner of the pipeline and completely push out flammable and explosive residues such as organosilicon compounds or organometallic substances. At the same time, the integrity of the nitrogen protective atmosphere should be maintained to prevent oxygen from seeping in and causing a reaction.

[0029] In summary, by controlling key parameters such as flow rate, temperature, scaling status, and pressure in the exhaust gas pipeline, efficient treatment of volatile organic compounds, particulate matter, and unreacted chemical substances in the exhaust gas is achieved, improving the efficiency of exhaust gas treatment and significantly reducing the potential environmental hazards of exhaust gas emissions.

[0030] In one embodiment, the step of connecting the exhaust gas pipeline to a chemical vapor deposition apparatus, acquiring exhaust gas flow rate data within the exhaust gas pipeline, and adjusting the flow rate of the exhaust gas pipeline based on the difference between the exhaust gas flow rate data and the target flow rate includes: The exhaust gas pipeline is connected to the exhaust gas outlet of the chemical vapor deposition equipment, and the flow distribution data in the exhaust gas pipeline is collected based on the flow sensor in the exhaust gas pipeline. The actual flow velocity at each cross section of the pipe is calculated based on the flow distribution data and the cross-sectional area parameters of the exhaust pipe, thus obtaining actual flow velocity distribution data that includes the spatial distribution and temporal variation of the flow velocity. The velocity deviation value of each section in the exhaust gas pipeline is calculated based on the difference between the actual velocity distribution data and the preset target velocity. The multiple velocity deviation values ​​are then weighted and averaged according to the changing trend of the flow distribution data to obtain the velocity deviation parameter. The operating power of the vacuum pump is controlled according to the flow rate deviation parameter to adjust the flow rate in the exhaust gas duct, wherein the vacuum pump is connected to both the exhaust gas duct and the chemical vapor deposition equipment.

[0031] In this embodiment, the exhaust gas pipeline is connected to the exhaust gas outlet of the chemical vapor deposition equipment, such as using a flange connection or quick-clamp sealing method, to ensure smooth entry of the exhaust gas from the equipment outlet into the pipeline while preventing leakage. After connection, flow distribution data within the exhaust gas pipeline is collected based on flow sensors within the pipeline. These flow sensors are typically arranged at different locations within the pipeline, such as the inlet, middle, and outlet sections, forming a sensor network. Each sensor monitors the volumetric flow rate of the local airflow in real time, for example, by using a thermal mass flow meter or turbine flow meter to capture the volume of exhaust gas passing through per unit time, thereby obtaining comprehensive flow distribution data. Based on the flow distribution data and the cross-sectional area parameters of the exhaust gas pipeline, the actual flow velocity at each cross-section within the pipeline is calculated, thus obtaining actual velocity distribution data that includes both spatial and temporal velocity variations. The cross-sectional area parameter of the exhaust gas pipeline is a predetermined fixed value, i.e., the pipeline's design specifications. The actual flow velocity is calculated at each cross-section, forming a dynamic dataset. Based on the difference between the actual flow velocity distribution data and the preset target flow velocity, the flow velocity deviation value of each section in the exhaust pipe is calculated. The preset target flow velocity can be obtained through simulation or historical data analysis. For example, when the flow velocity is controlled between 5 and 15 liters per minute, the actual flow velocity of each section is compared with this target value point by point. For example, if the actual flow velocity of a certain section is 10 liters per minute and the target is 8 liters per minute, the deviation value is positive 2 liters per minute; otherwise, it is negative, generating an array of deviation values. Multiple flow velocity deviation values ​​are weighted and averaged according to the changing trend of the flow distribution data. The changing trend refers to the dynamic pattern of the flow data over time. For example, if the flow rate rises sharply in the first few minutes and then stabilizes, the trend is identified as rising and then stabilizing. In the weighted averaging, deviation values ​​with obvious trends are given higher weights. For example, a sliding window algorithm is used to apply weighting factors to the deviation values ​​of the most recent 10 sampling points. The weighting factors are derived from the trend slope calculation; for example, the larger the slope, the higher the weight. A single flow velocity deviation parameter is obtained, such as an overall deviation of 1.5 liters per minute. The operating power of the vacuum pump is controlled based on the flow rate deviation parameter to adjust the flow rate within the exhaust gas duct. The vacuum pump is connected to both the exhaust gas duct and the chemical vapor deposition equipment. For example, if the deviation parameter is positive, indicating that the flow rate is too high, the pump speed or power output is reduced, such as from 100% to 80%, thus slowing down the pumping speed and bringing the flow rate closer to the target. Conversely, if the deviation is negative, the power is increased to 120% to accelerate the pumping. This adjustment is a closed loop, with real-time feedback through a PID controller. The pump power range is preset based on equipment specifications, such as a maximum power of 5 kW and a minimum of 1 kW, ensuring safe operation. Throughout the process, parameters such as cross-sectional area are static values ​​determined during design, the target flow rate is a dynamic benchmark obtained through experimental optimization but fixed in actual use, and the deviation value and deviation parameter are dynamic indicators calculated in real time. All of these are integrated through an embedded controller or PLC system to achieve automated adjustment, thereby stabilizing the exhaust gas flow rate within the target range.

[0032] In one embodiment, the step of acquiring temperature data at opposite ends of the exhaust pipe and adjusting the temperature at opposite ends of the exhaust pipe based on the difference between the temperature data and a preset temperature includes: Based on the temperature sensors at the inlet and outlet ends of the exhaust pipe, the real-time temperature of the airflow at both ends of the exhaust pipe is collected to obtain initial temperature distribution data including the temperature changes of the inlet and outlet ends over time. The initial temperature distribution data is compared point by point with the preset target temperature to obtain the temperature deviation data between the inlet and outlet temperatures. The temperature control device of the exhaust pipe is dynamically adjusted according to the temperature deviation parameter to obtain a heat exchange control signal. The heat compensation values ​​at both ends of the exhaust pipe are obtained based on the temperature deviation distribution parameters, and the heat transfer medium is preheated through the heating chamber based on the heat compensation values. The heat-conducting medium is transported to the output mixing chamber and dynamically mixed with the low-temperature heat-conducting medium stored in the room temperature chamber to obtain the target temperature medium. The target temperature medium is transported to the heat exchange area corresponding to the exhaust gas pipe, so that the temperature at both ends of the exhaust gas pipe reaches the preset temperature range.

[0033] In the above embodiments, temperature sensors are installed at the inlet and outlet ends of the exhaust gas duct to collect temperature data of the airflow within the duct in real time. The collected data includes the temperature value at a certain moment and the temperature change trend over time, thus forming initial temperature distribution data. Temperature distribution maps containing both time and spatial dimensions are generated by collecting data at fixed time intervals (e.g., per second or per millisecond). The initial temperature distribution data is compared point-by-point with a preset target temperature to calculate the temperature deviation between the inlet and outlet ends. The preset target temperature is set according to the specific requirements of the CVD coating process, comprehensively determined based on the exhaust gas composition, duct material, and operating conditions of the chemical vapor deposition equipment. For example, the exhaust gas treatment process requires the inlet temperature to be maintained at 300°C to ensure reaction activity, while the outlet temperature may need to be controlled at 250°C to avoid overheating of the equipment. The point-by-point comparison process involves subtracting the target temperature from the actual temperature at each moment to obtain the deviation value. For example, if the temperature measured at the inlet end at a certain moment is 310°C, while the target temperature is 300°C, the deviation value is +10°C. These deviation values ​​are summarized to form temperature deviation data. Heat exchange control signals are generated based on temperature deviation data to dynamically adjust the temperature control device in the exhaust gas pipeline. The temperature control device is a heating or cooling device, either external or internal to the pipeline, such as an electric heater, cooling water circulation system, or heat exchanger. Dynamic adjustment means adjusting the operating status of the temperature control device in real time according to the direction and magnitude of the deviation. For example, if the inlet temperature is too high, the heater power is reduced or the flow rate of the cooling medium is increased; if the temperature deviation continues to increase, the adjustment intensity is increased; if the deviation is small and stable, fine-tuning is performed to avoid over-adjustment. During the adjustment process, heat compensation values ​​at both ends of the exhaust gas pipeline are calculated based on temperature deviation distribution parameters. Temperature deviation distribution parameters are statistical characteristics extracted from temperature deviation data, such as the average value, maximum value, or rate of change of the deviation. These parameters reflect the spatial distribution and temporal trend of the temperature deviation. The calculation of heat compensation values ​​is based on thermodynamic principles and can be based on the heat capacity of the airflow inside the pipeline, the thermal conductivity of the pipeline material, and the influence of ambient temperature. The compensation value is expressed in energy units (such as joules) to guide the operation of the heating chamber. The heating chamber is a device for preheating the heat-conducting medium, which can be a liquid (such as heat transfer oil) or a gas (such as hot air). Its function is to transfer heat to specific areas of the pipeline. The degree of preheating is determined by the heat compensation value. For example, if 1000 joules of heat compensation is required, the heating chamber will heat the heat-conducting medium to a specific temperature to meet this requirement. The preheated heat-conducting medium is then transported to the output mixing chamber, where it is dynamically mixed with the low-temperature heat-conducting medium stored in the ambient temperature chamber to generate the medium at the target temperature. The output mixing chamber is a specially designed mixing device capable of controlling the mixing ratio of the high-temperature and low-temperature media.For example, if the target temperature is 280°C, the preheating medium temperature is 350°C, and the low-temperature medium temperature is 20°C, the flow ratio of the two can be controlled by adjusting the valves to bring the temperature of the mixed medium close to 280°C. The medium at the target temperature is then delivered to the heat exchange area of ​​the exhaust gas pipeline through a heat exchanger on the outside of the pipeline or through heat exchange tubes inside the pipeline. The medium contacts the outer wall of the exhaust gas pipeline through the heat exchanger, transferring heat to the exhaust gas or absorbing heat from the exhaust gas, thereby bringing the temperature at both ends of the pipeline to the preset range.

[0034] In one embodiment, the step of obtaining the scaling status value inside the exhaust gas pipe includes: Based on the multi-point ultrasonic sensor array inside the exhaust pipe, ultrasonic signals are emitted to the inner wall of the pipe, and the sound wave signals reflected back from the inner wall of the pipe are received to obtain initial sound wave reflection data. The initial sound wave reflection data includes the sound wave propagation time difference at different time points of multiple sampling points. The scale thickness at each sampling point on the inner wall of the exhaust pipe is calculated based on the initial acoustic wave reflection data, and scale thickness distribution data is generated. By comparing the thickness changes of the same sampling point at different time points in the scale thickness distribution data, the thickness change values ​​of multiple sampling points are integrated and analyzed to obtain a scale state value that represents the overall scale degree.

[0035] In the above embodiment, an array of multi-point ultrasonic sensors within the exhaust duct transmits ultrasonic signals to the inner wall of the duct. This array refers to ultrasonic sensors installed on the inner wall of the exhaust duct, distributed in an array to cover different areas of the duct. The transmission and reception of ultrasonic signals are based on the principle of the difference in the propagation speed of ultrasound in different media. When the ultrasound encounters a scale layer on the inner wall of the duct, the reflected sound wave signal changes due to the difference in acoustic properties between the scale material (such as deposited particles or chemicals) and the duct material. The initial acoustic reflection data includes the time difference of sound wave propagation at multiple sampling points at different time points. Here, the sampling point refers to the specific location of the inner wall of the duct covered by the sensor array. The time difference of sound wave propagation is the time interval from transmission to reception of the ultrasound, reflecting the presence and thickness of scale on the inner wall of the duct. The time difference of sound wave propagation is obtained using a timing device. After each ultrasonic wave transmission, the sensor records the signal return time, and multiple measurements are used to ensure data stability. The scale thickness at each sampling point on the inner wall of the exhaust duct is calculated based on the initial acoustic reflection data, converting the time difference of sound wave propagation into a specific scale thickness value. The propagation speed of ultrasound waves in pipe materials and scale deposits is known, typically obtained through experimental measurements or reference material databases. For example, the pipe material might be metal, while the scale might be carbon deposits or oxides, resulting in different sound wave propagation speeds. The thickness of the scale layer can be estimated by comparing the actual propagation time difference with the standard propagation time of the pipe material in a scale-free state. The thickness at each sampling point is calculated by averaging the sound wave propagation time differences from multiple measurements to reduce the impact of measurement errors. The thickness data from all sampling points are aggregated to form a scale thickness distribution dataset, which includes the thickness values ​​at each sampling point and reflects the spatial distribution of scale on the pipe's inner wall. For example, some areas are more prone to scale accumulation due to slower airflow or higher temperatures, resulting in thicker thickness values ​​in these areas compared to other areas. Comparing the thickness changes at the same sampling point at different time points in the scale thickness distribution dataset—for example, if the thickness at a sampling point increases from an initial 0.1 mm to 0.3 mm—indicates that scale buildup in that area is intensifying. The thickness change is calculated by subtracting the thickness value from the previous time point to obtain an increment or decrement. The thickness variation values ​​from multiple sampling points need to be integrated and analyzed to generate a scaling status value. This integration analysis can employ weighted averaging or statistical analysis methods. Weighted averaging assigns different weights based on the importance of the sampling point's location. For example, sampling points near the exhaust pipe inlet or outlet may have a greater impact on exhaust gas flow and therefore receive higher weights. The weighting coefficients are typically determined based on pipe design parameters, airflow characteristics, and experimental data, and are obtained through multiple experiments and optimization.

[0036] In one embodiment, the step of introducing nitrogen gas into the exhaust gas pipe if the scaling state value is greater than a preset threshold includes: The scaling state value is compared with a preset threshold using a comparator circuit to generate a trigger signal for controlling nitrogen gas. The trigger signal is high when the scaling state value exceeds the preset threshold and low when it does not exceed the preset threshold. Nitrogen gas is controlled to enter the exhaust gas pipeline through the gas transmission pipeline, so that the nitrogen gas is distributed in the scale area on the inner wall of the exhaust gas pipeline, forming a nitrogen protective atmosphere covering the exhaust gas pipeline.

[0037] In this embodiment, a comparator circuit compares the scaling state value with a preset threshold in real time. The comparator circuit compares the input scaling state value (represented as a digital signal) with the preset threshold and outputs a high-level or low-level signal based on the comparison result. When the scaling state value exceeds the preset threshold, the comparator outputs a high-level signal, indicating that the scaling degree in the pipeline has reached a level requiring intervention; conversely, if it does not exceed the threshold, it outputs a low-level signal, indicating that normal operation can continue. The generation of the high-level signal signifies that the conditions for triggering nitrogen gas introduction have been met. This signal is directly transmitted to the control system to start the nitrogen supply device. Nitrogen gas is controlled to enter the exhaust gas pipeline through the gas delivery pipeline. The nitrogen gas covers the scaling area on the inner wall of the pipeline, forming a protective atmosphere. Nitrogen is an inert gas, and its function is to reduce the oxygen concentration by filling the internal space of the pipeline, thereby isolating flammable and explosive scaling residues from contact with oxygen and preventing possible chemical reactions. In another embodiment, a one-in-one-backup piping design can be adopted, meaning that while the main pipeline is operating, the backup pipeline is always on standby, allowing for seamless switching and maintaining production continuity should the main pipeline need to be shut down for maintenance due to scaling or other issues. After a trigger signal is generated, the nitrogen supply device will start according to the signal command, and nitrogen will enter the exhaust gas pipeline through a solenoid valve. The opening of the solenoid valve will be dynamically adjusted according to real-time demand to control the flow rate and distribution of nitrogen. For example, when the scaling condition value just exceeds the threshold, a small amount of nitrogen is needed to form a protective atmosphere; when the scaling degree increases significantly, the nitrogen flow rate needs to be increased to ensure safety, executed by a programmable logic controller (PLC) or similar control unit. The control system will adjust the timing and amount of nitrogen flow based on the changing trend of the scaling condition value, ensuring effective coverage of the scaling area while avoiding nitrogen waste and reducing operating costs.

[0038] In one embodiment, the step of obtaining the pressure value inside the exhaust gas pipe and adjusting the nitrogen flow rate and flow time based on the pressure value includes: The pressure value of the airflow inside the exhaust pipe is obtained by the pressure sensor on the inner wall of the exhaust pipe, and the initial pressure distribution data is obtained. Extract the maximum fluctuation rate and maximum decrease rate of the pressure value at each sampling point in the initial pressure distribution data to obtain the pressure fluctuation parameters; Based on the comparison between the pressure fluctuation parameter and the preset pressure fluctuation threshold, an initial adjustment coefficient for the nitrogen injection rate is obtained; wherein, when the pressure fluctuation parameter exceeds the preset pressure fluctuation threshold, the initial adjustment coefficient is increased, and when the pressure fluctuation parameter is lower than the preset pressure fluctuation threshold, the initial adjustment coefficient is decreased. Based on the product of the initial adjustment coefficient and the real-time pressure value in the exhaust gas pipeline, the adjustment value of the nitrogen inlet is calculated, and the nitrogen inlet time is calculated according to the duration of the pressure fluctuation parameter to form the adjustment parameter; The operating status of the nitrogen supply device is controlled according to the adjustment parameters. The nitrogen supply device is connected to the inlet of the exhaust gas pipeline through a solenoid valve, and the opening degree of the solenoid valve is adjusted according to the adjustment value of the nitrogen flow rate.

[0039] In this embodiment, the airflow pressure value inside the exhaust pipe is obtained through a pressure sensor on the inner wall of the pipe. The sensor monitors the pressure changes of the airflow inside the pipe and records the pressure values ​​of multiple sampling points at different time points, forming a pressure distribution dataset containing time and spatial dimensions. Based on the initial pressure distribution data, the maximum fluctuation rate and maximum drop rate of the pressure value at each sampling point are extracted to generate pressure fluctuation parameters. The maximum fluctuation rate reflects the drastic change in pressure inside the pipe in a short period of time. For example, when the exhaust gas flow suddenly increases or decreases, the pressure may rise or fall rapidly. The maximum drop rate focuses on the speed at which the pressure decreases, as this may be related to increased resistance due to scaling inside the pipe or obstruction of airflow. The process of extracting these two parameters involves performing time series analysis on the initial pressure distribution data, calculating the rate of pressure change at each sampling point per unit time, and identifying the points with the fastest change and the fastest drop. After obtaining the pressure fluctuation parameters, these parameters are compared with a preset pressure fluctuation threshold. The preset pressure fluctuation threshold is a reference value set based on experience and experimental data. For example, it can be set that when the maximum fluctuation rate in the pressure fluctuation parameters exceeds 5 Pascals per second, or the maximum drop rate exceeds 3 Pascals per second, it is considered to exceed the preset pressure fluctuation threshold. The comparison process is implemented through a comparator circuit. When the pressure fluctuation parameter is higher than the threshold, it indicates that the airflow in the pipeline is unstable, possibly due to scaling, blockage, or turbulent airflow. In this case, the nitrogen injection rate needs to be increased, and the initial adjustment coefficient will increase accordingly. Conversely, if the pressure fluctuation parameter is lower than the threshold, it indicates that the airflow in the pipeline is relatively stable, and the nitrogen injection rate can be appropriately reduced, thus decreasing the initial adjustment coefficient. Based on the product of the initial adjustment coefficient and the real-time pressure value in the exhaust gas pipeline, the adjustment value of the nitrogen injection rate is calculated. Multiplying the initial adjustment coefficient by the real-time pressure value is equivalent to combining the overall pressure level and fluctuation characteristics of the pipeline to calculate a comprehensive nitrogen injection rate adjustment value. For example, when the real-time pressure value is high and the fluctuation is large, the adjustment value will be larger. The injection time is determined based on the duration of the pressure fluctuation parameter. For example, if the pressure fluctuation lasts for a long time, it indicates that the instability in the pipeline may be more severe, requiring a longer nitrogen injection time to stabilize the environment. The operation of the nitrogen supply device is controlled according to the adjustment parameter. The nitrogen supply device is connected to the inlet of the exhaust gas pipeline through a solenoid valve, and the opening of the solenoid valve is precisely adjusted according to the nitrogen injection rate adjustment value. The opening control of a solenoid valve is a dynamic process. The control system translates the adjustment parameters into specific solenoid valve opening commands. For example, when the adjustment value is large, the solenoid valve opening increases, allowing more nitrogen to enter the pipeline; when the adjustment value is small, the solenoid valve opening decreases, reducing the nitrogen flow and creating a protective nitrogen atmosphere to cover the scaled area on the inner wall of the exhaust gas pipeline.

[0040] refer to Figures 2 to 4The present invention also discloses an exhaust gas treatment device, applied to an exhaust gas treatment method based on CVD coating process as described in any of the above claims, comprising: The exhaust gas duct 1 is used to transport the exhaust gas to be treated. A temperature sensor 5, an ultrasonic sensor, a pressure sensor, and a flow sensor are installed inside the exhaust gas duct 1. A vacuum pump 2 is installed at the outlet of the exhaust gas duct 1, with a check valve installed at one end. One end of the vacuum pump 2 is connected to the outlet of the chemical vapor deposition equipment 4, and the other end is connected to the inlet of the exhaust gas duct 1 through the check valve. A temperature control device 3 is connected to the exhaust gas duct 1 and is used to adjust the temperature at opposite ends within the exhaust gas duct 1. A control unit is electrically connected to the flow sensor, temperature sensor 5, ultrasonic sensor, pressure sensor, vacuum pump 2, and temperature control device 3, respectively. It receives data collected by each sensor, processes it, and generates control signals to control the operating status of each device, thus completing the exhaust gas treatment process.

[0041] The double-layer sandwich structure includes a temperature-controlled sandwich 11 and an insulation layer 12, which are sequentially disposed on the outer wall of the exhaust gas duct 1. The temperature-controlled sandwich 11 is filled with a temperature-adjustable heat-conducting medium, and its temperature is controlled by connecting it to the temperature control device 3. The exhaust gas duct 1 has a cylindrical structure and is inclined at an angle of 0.17 to 0.5 degrees relative to the outlet of the chemical vapor deposition equipment 4 along its axial direction. The temperature control device 3 includes a heating chamber 31, a mixing chamber 32, a cooling chamber 33, and a heat transfer medium conveying pipe 35. The heating chamber 31 is used to preheat the heat transfer medium. The mixing chamber 32 is used to dynamically mix the preheated heat transfer medium with a room temperature heat transfer medium to obtain a medium at the target temperature. The cooling chamber 33 is used to cool the heat transfer medium. The heat transfer medium conveying pipe 35 is responsible for conveying the heat transfer medium processed by the heating chamber 31, the mixing chamber 32, and the cooling chamber 33 to the heat exchange area corresponding to the exhaust gas pipe 1.

[0042] In this embodiment, the exhaust gas duct 1 is used to transport the exhaust gas to be treated, and a series of sensors and control units are used to achieve an efficient and stable exhaust gas treatment process. The exhaust gas duct 1 integrates a temperature sensor 5, an ultrasonic sensor, a pressure sensor, and a flow sensor. These sensors can collect the physical parameters of the exhaust gas in the duct in real time, such as temperature, pressure, flow rate, and possible particle or liquid accumulation. The temperature sensor 5 monitors the exhaust gas temperature to ensure that the thermal environment inside the duct meets the treatment requirements; the pressure sensor detects pressure changes inside the duct to prevent equipment failure due to abnormal pressure; the flow sensor monitors the flow rate and volume of the exhaust gas; and the ultrasonic sensor can be used to detect whether there are deposits or blockages inside the duct. The data from these sensors is centrally processed by the control unit. The control unit generates corresponding control signals based on the received data to adjust the operating status of equipment such as the vacuum pump 2 and the temperature control device 3, thereby achieving automation and precision in the exhaust gas treatment process.

[0043] One end of vacuum pump 2 is connected to the outlet of the CVD equipment, and the other end is connected to the inlet of exhaust gas pipe 1 via a check valve. The check valve is designed to effectively prevent backflow of exhaust gas, ensuring it flows in a predetermined direction and avoiding damage to the CVD equipment or vacuum pump 2. The check valve uses fluoropolymer rubber as the sealing material for its central support. This material has excellent high-temperature and corrosion resistance, extending the service life of the sealing ring and adapting to potentially high-temperature or corrosive components in the CVD exhaust gas. The connection direction of exhaust gas pipe 1 is set according to the exhaust gas outlet temperature of vacuum pump 2. A metal corrugated expansion joint is installed at the connection between the pipe and the equipment to absorb displacement caused by thermal expansion and contraction, reducing the risk of pipe deformation or damage to the connection.

[0044] The exhaust gas duct 1 adopts a straight cylindrical structure and is inclined at an angle of 0.17~0.5 relative to the exhaust port of the CVD equipment. This design is based on fluid mechanics principles and aims to reduce the resistance to exhaust gas flow and prevent liquid accumulation. The straight cylindrical duct effectively reduces the number of bends, making the exhaust gas flow smoother. The duct inclination design (not less than 0.3%) allows the exhaust gas to flow smoothly to the treatment equipment or discharge port, avoiding the accumulation of liquid or particulate matter inside the duct. The inclination angle setting must also consider the limitations of the actual installation space to ensure that the duct layout meets both functional requirements and conforms to the overall structure of the equipment. The duct diameter is selected based on the exhaust gas flow rate of the CVD equipment, the exhaust gas composition (such as density and viscosity), and the design-required flow velocity range. If the exhaust gas contains a large number of solid particles or high-viscosity substances, a larger duct diameter needs to be selected to prevent blockage; if the exhaust gas temperature is high, the duct diameter also needs to be appropriately increased to accommodate the gas volume expansion.

[0045] Temperature control device 3 is used to adjust the temperature at opposite ends of the exhaust gas pipeline 1 to optimize the thermal energy conversion efficiency of exhaust gas treatment. Temperature control device 3 includes a heating chamber 31, a mixing chamber 32, a cooling chamber 33, and a heat transfer medium conveying pipe 35. The heating chamber 31 is responsible for preheating the heat transfer medium to reach the initial temperature calculated by the PLC control system. The mixing chamber 32 dynamically mixes the preheated heat transfer medium with a room-temperature heat transfer medium to regulate the medium temperature to meet target requirements. The cooling chamber 33 cools the heat transfer medium to ensure the system can respond quickly to temperature changes. The heat transfer medium conveying pipe 35 transports the treated heat transfer medium to the heat exchange area of ​​the exhaust gas pipeline 1, achieving uniform temperature control within the pipeline. The pipeline constant temperature device is connected to the exhaust gas pipeline 1 via a quick-connect interface and forms a closed-loop control with the control system through temperature sensor 5 and pressure sensor 5. The temperature sensor 5 inside the pipeline provides real-time temperature data feedback, while the temperature sensor 5 at the return port monitors the output temperature of the heating chamber, ensuring that the output of temperature control device 3 is stable and meets the set requirements. In one embodiment, the system also includes a compressor 34 and liquid level sensors 36 disposed on the heating chamber 31 and the cooling chamber 33. The compressor 34 is used to pressurize the heat transfer medium to improve its flow efficiency in the heat transfer medium delivery pipe 35, ensuring that the temperature control device 3 can quickly and effectively adjust the temperature in the exhaust gas pipe 1. The liquid level sensors 36 are disposed on the heating chamber 31 and the cooling chamber 33 respectively, and are used to monitor the liquid level of the heat transfer medium in the chamber in real time. When the liquid level is lower or higher than a preset value, the liquid level sensor 36 will promptly feed back the signal to the PLC control system. The control system adjusts the replenishment or discharge of the heat transfer medium according to the received signal to ensure the normal operation of the heating chamber 31 and the cooling chamber 33, thereby maintaining the stability and reliability of the entire exhaust gas treatment system.

[0046] In this embodiment, the exhaust gas duct 1 uses a double-layer sandwich structure, including a temperature-controlled sandwich 11 and an insulation layer 12, which are sequentially disposed on the outer wall of the exhaust gas duct 1. The temperature-controlled sandwich 11 is filled with a heat-conducting medium with adjustable temperature, and achieves dynamic temperature control by connecting with the temperature control device 3. That is, the temperature-controlled sandwich 11 is a heat exchange area, which can effectively maintain the temperature stability inside the duct and prevent heat loss caused by fluctuations in the external ambient temperature or changes in the temperature of the exhaust gas itself. The insulation layer 12 further reduces heat loss and improves thermal energy utilization efficiency. Temperature changes in the exhaust gas duct 1 may lead to thermal expansion and contraction. Therefore, the double-layer sandwich design not only optimizes temperature control, but also reduces the risk of duct deformation through flexible connections or expansion joints.

[0047] In another embodiment, to prevent safety hazards caused by static electricity, an electrostatic eliminator can be installed inside the pipeline to reduce the risk of fire or explosion caused by static sparks. The control unit integrates pressure control, flow control, and temperature control functions. Through electrical connections with various sensors and actuators, it achieves automated management of the exhaust gas treatment process. The PLC control system can dynamically adjust the operating status of the vacuum pump 2, temperature control device 3, and pipeline temperature control device based on sensor feedback data to ensure stable operation of the equipment under different working conditions.

[0048] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for treating exhaust gas from a CVD (CVD) device, characterized in that, include: Provide an exhaust gas duct, connect the exhaust gas duct to the CVD equipment, obtain exhaust gas flow data in the exhaust gas duct, and adjust the flow rate of the exhaust gas duct according to the difference between the exhaust gas flow data and the target flow rate. Acquire temperature data at opposite ends of the exhaust pipe, and adjust the temperature at opposite ends of the exhaust pipe based on the difference between the temperature data and a preset temperature; Obtain the scaling status value inside the exhaust pipe; if the scaling status value is greater than a preset threshold, introduce nitrogen into the exhaust pipe. The pressure value inside the exhaust gas pipeline is obtained, and the nitrogen flow rate and flow time are adjusted according to the pressure value to complete the exhaust gas treatment process.

2. The exhaust gas treatment method based on CVD coating process according to claim 1, characterized in that, The steps of connecting the exhaust gas pipeline to the chemical vapor deposition equipment, acquiring exhaust gas flow rate data within the exhaust gas pipeline, and adjusting the flow rate of the exhaust gas pipeline based on the difference between the exhaust gas flow rate data and the target flow rate include: The exhaust gas pipeline is connected to the exhaust gas outlet of the chemical vapor deposition equipment, and the flow distribution data in the exhaust gas pipeline is collected based on the flow sensor in the exhaust gas pipeline. The actual flow velocity at each cross section of the pipe is calculated based on the flow distribution data and the cross-sectional area parameters of the exhaust pipe, thus obtaining actual flow velocity distribution data that includes the spatial distribution and temporal variation of the flow velocity. The velocity deviation value of each section in the exhaust gas pipeline is calculated based on the difference between the actual velocity distribution data and the preset target velocity. The multiple velocity deviation values ​​are then weighted and averaged according to the changing trend of the flow distribution data to obtain the velocity deviation parameter. The operating power of the vacuum pump is controlled according to the flow rate deviation parameter to adjust the flow rate in the exhaust gas duct, wherein the vacuum pump is connected to both the exhaust gas duct and the chemical vapor deposition equipment.

3. The exhaust gas treatment method based on CVD coating process according to claim 1, characterized in that, The step of acquiring temperature data at opposite ends of the exhaust pipe and adjusting the temperature at opposite ends of the exhaust pipe based on the difference between the temperature data and a preset temperature includes: Based on the temperature sensors at the inlet and outlet ends of the exhaust pipe, the real-time temperature of the airflow at both ends of the exhaust pipe is collected to obtain initial temperature distribution data including the temperature changes of the inlet and outlet ends over time. The initial temperature distribution data is compared point by point with the preset target temperature to obtain the temperature deviation data between the inlet and outlet temperatures. The temperature control device of the exhaust pipe is dynamically adjusted according to the temperature deviation parameter to obtain a heat exchange control signal. The heat compensation values ​​at both ends of the exhaust pipe are obtained based on the temperature deviation distribution parameters, and the heat transfer medium is preheated through the heating chamber based on the heat compensation values. The heat-conducting medium is transported to the output mixing chamber and dynamically mixed with the low-temperature heat-conducting medium stored in the room temperature chamber to obtain the target temperature medium. The target temperature medium is transported to the heat exchange area corresponding to the exhaust gas pipe, so that the temperature at both ends of the exhaust gas pipe reaches the preset temperature range.

4. The exhaust gas treatment method based on CVD coating process according to claim 1, characterized in that, The step of obtaining the scaling status value inside the exhaust gas pipe includes: Based on the multi-point ultrasonic sensor array inside the exhaust pipe, ultrasonic signals are emitted to the inner wall of the pipe, and the sound wave signals reflected back from the inner wall of the pipe are received to obtain initial sound wave reflection data. The initial sound wave reflection data includes the sound wave propagation time difference at different time points of multiple sampling points. The scale thickness at each sampling point on the inner wall of the exhaust pipe is calculated based on the initial acoustic wave reflection data, and scale thickness distribution data is generated. By comparing the thickness changes of the same sampling point at different time points in the scale thickness distribution data, the thickness change values ​​of multiple sampling points are integrated and analyzed to obtain a scale state value that represents the overall scale degree.

5. The exhaust gas treatment method based on CVD coating process according to claim 1, characterized in that, The step of introducing nitrogen into the exhaust gas pipe if the scaling condition value is greater than a preset threshold includes: The scaling state value is compared with a preset threshold using a comparator circuit to generate a trigger signal for controlling nitrogen gas. The trigger signal is high when the scaling state value exceeds the preset threshold and low when it does not exceed the preset threshold. Nitrogen gas is controlled to enter the exhaust gas pipeline through the gas transmission pipeline, so that the nitrogen gas is distributed in the scale area on the inner wall of the exhaust gas pipeline, forming a nitrogen protective atmosphere covering the exhaust gas pipeline.

6. The exhaust gas treatment method based on CVD coating process according to claim 1, characterized in that, The step of obtaining the pressure value inside the exhaust gas pipe and adjusting the nitrogen flow rate and flow time based on the pressure value includes: The pressure value of the airflow inside the exhaust pipe is obtained by the pressure sensor on the inner wall of the exhaust pipe, and the initial pressure distribution data is obtained. Extract the maximum fluctuation rate and maximum decrease rate of the pressure value at each sampling point in the initial pressure distribution data to obtain the pressure fluctuation parameters; Based on the comparison between the pressure fluctuation parameter and the preset pressure fluctuation threshold, an initial adjustment coefficient for the nitrogen injection rate is obtained; wherein, when the pressure fluctuation parameter exceeds the preset pressure fluctuation threshold, the initial adjustment coefficient is increased, and when the pressure fluctuation parameter is lower than the preset pressure fluctuation threshold, the initial adjustment coefficient is decreased. Based on the product of the initial adjustment coefficient and the real-time pressure value in the exhaust gas pipeline, the adjustment value of the nitrogen inlet is calculated, and the nitrogen inlet time is calculated according to the duration of the pressure fluctuation parameter to form the adjustment parameter; The operating status of the nitrogen supply device is controlled according to the adjustment parameters. The nitrogen supply device is connected to the inlet of the exhaust gas pipeline through a solenoid valve, and the opening degree of the solenoid valve is adjusted according to the adjustment value of the nitrogen flow rate.

7. A tail gas treatment device, characterized in that, The exhaust gas treatment method based on CVD coating process according to any one of claims 1 to 6 includes: An exhaust gas duct is used to transport exhaust gas to be treated. The exhaust gas duct is equipped with a temperature sensor, an ultrasonic sensor, a pressure sensor and a flow sensor. A vacuum pump is provided, and a check valve is provided at the outlet of the exhaust gas pipeline. One end of the vacuum pump is connected to the outlet of the chemical vapor deposition equipment, and the other end is connected to the inlet of the exhaust gas pipeline through the check valve. A temperature control device, which is connected to the exhaust pipe, is used to adjust the temperature at opposite ends of the exhaust pipe. The control unit is electrically connected to the flow sensor, temperature sensor, ultrasonic sensor, pressure sensor, vacuum pump, and temperature control device, respectively. It is used to receive data collected by each sensor, process it, generate control signals, control the operating status of each device, and complete the exhaust gas treatment process.

8. The exhaust gas treatment device according to claim 7, characterized in that, It also includes a double-layer sandwich, which comprises a temperature-controlled sandwich and a heat-insulating layer, which are sequentially disposed on the outer wall of the exhaust gas pipe; wherein, the temperature-controlled sandwich is filled with a heat-conducting medium with adjustable temperature, and the temperature of the heat-conducting medium is regulated by connecting it with the temperature control device.

9. The exhaust gas treatment device according to claim 7, characterized in that, The exhaust pipe has a straight cylindrical structure, and the exhaust pipe is inclined at an angle of 0.17 to 0.5 relative to the outlet of the chemical vapor deposition equipment along the axial direction.

10. The exhaust gas treatment device according to claim 7, characterized in that, The temperature control device includes a heating chamber, a mixing chamber, a cooling chamber, and a heat transfer medium conveying pipeline. The heating chamber is used to preheat the heat transfer medium. The mixing chamber is used to dynamically mix the preheated heat transfer medium with a room temperature heat transfer medium in a proportional manner to obtain a medium at the target temperature. The cooling chamber is used to cool the heat transfer medium. The heat transfer medium conveying pipeline is responsible for conveying the heat transfer medium processed by the heating chamber, the mixing chamber, and the cooling chamber to the heat exchange area corresponding to the exhaust gas pipeline.

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