A method for reducing NOx emissions from a large flue x Partitioned synchronous measurement device

Abstract

This invention relates to NO in large flues. x In the field of measurement technology, specifically, it relates to a NO measurement method for large flues. x A zoned synchronous measurement device includes: a sampling module for sampling flue gas from multiple zones of a large flue to obtain flue gas samples from the corresponding zones; a flow measurement module for detecting the pressure at different locations along the transmission path of the flue gas samples; a control module for generating adjustment commands based on the pressure at different locations; and an adjustment module for adjusting the pressure along the transmission path based on the adjustment commands, so that flue gas samples from different zones arrive at the gas detection module synchronously. This invention achieves coordinated control of the flue gas sample transmission status by real-time detection and automatic adjustment of the pressure during the transmission process of flue gas samples from different zones, enabling flue gas samples from each zone to arrive at the gas detection module synchronously, effectively solving the problem of data distortion caused by asynchronous detection in existing technologies.

Description

TECHNICAL FIELD

[0001] The present application relates to NO x measurement technology field, and particularly relates to a NO x partition synchronous measurement device. BACKGROUND

[0002] Coal-fired boilers, industrial furnaces and large combustion devices will produce a large amount of flue gas containing nitrogen oxides during operation. In order to meet the environmental protection supervision requirements and realize fine emission control, it is usually necessary to detect the concentration of nitrogen oxides in different partitions of the flue gas inside the large flue. However, the flue gas flow field in the large flue is complex, and there are problems such as temperature difference, flow rate difference and uneven pressure distribution between different partitions, which leads to obvious time lag difference and flow inconsistency of the flue gas in each partition during sampling and transmission.

[0003] In the prior art, single-point sampling or multi-point sampling but independent transmission detection is usually used for NO x monitoring. The single-point detection method cannot truly reflect the composition difference of flue gas in different regions of the large flue; and the multi-point independent detection method can cover different regions, but the detection results often have different degrees of asynchronization problem, thereby affecting the timeliness and accuracy of the detection data. SUMMARY

[0004] (I) Invention purpose

[0005] The purpose of the present application is to provide a NO x partition synchronous measurement device for a large flue, which realizes coordinated control of the flue gas sample transmission state by real-time detection and automatic adjustment of the pressure in the transmission process of the flue gas samples in different partitions, so that the flue gas samples in each partition can be synchronized to reach the gas detection module, and effectively solves the problem of data distortion caused by asynchronization in the prior art.

[0006] (II) Technical solutions

[0007] To solve the above problems, the present application provides a NO x partition synchronous measurement device for a large flue, comprising: a sampling module, a flow measurement module, an adjustment module, a gas detection module and a control module.

[0008] The sampling module, the flow measurement module, the adjustment module and the gas detection module are respectively connected with the control module.

[0009] The sampling module is used for sampling the flue gas in multiple partitions of the large flue, obtaining the flue gas samples of the corresponding partitions, and transmitting the flue gas samples to the flow measurement module.

[0010] The flow measurement module is used for detecting the pressure at different positions on the transmission path of the flue gas sample and transmitting to the control module;

[0011] The control module generates adjustment instructions based on the pressure at different positions and transmits to the adjustment module;

[0012] The adjustment module adjusts the pressure of the transmission path based on the adjustment instructions, so that the flue gas samples in different partitions reach the corresponding gas detection module synchronously;

[0013] The gas detection module is used for component detection of the flue gas sample, and synchronously obtains NO x detection data.

[0014] Another aspect of the present application, preferably, the sampling module comprises several sampling probes, the sampling probes are respectively arranged in each partition of the large flue, for respectively obtaining flue gas sample from the corresponding partition;

[0015] Each of the sampling probes is communicated with the flow measurement module through a sampling pipeline, so as to transport the flue gas sample obtained from the corresponding partition to the flow measurement module.

[0016] Another aspect of the present application, preferably, the flow measurement module comprises a first pressure detection unit, a second pressure detection unit and a pressure adjustment unit;

[0017] The first pressure detection unit, the pressure adjustment unit and the second pressure detection unit are connected in sequence;

[0018] The first pressure detection unit is used for detecting the initial pressure of the flue gas sample output by the sampling probe on the transmission path, and transmitting the detection result to the control module;

[0019] The pressure adjustment unit is used for adjusting the pressure of the flue gas sample passing through the first pressure detection unit;

[0020] The second pressure detection unit is used for detecting the pressure of the flue gas sample after passing through the pressure adjustment unit and transmitting the detection result to the control module.

[0021] Another aspect of the present application, preferably, the pressure adjustment unit comprises a first pipeline and a second pipeline, the diameter of the first pipeline is greater than that of the second pipeline;

[0022] The first pressure detection unit is arranged in the first pipeline, and the second pressure detection unit is arranged in the second pipeline, and the flue gas sample moves from the first pipeline to the second pipeline.

[0023] Another aspect of the present application, preferably, the adjustment module comprises a gas source unit and a pressure regulator;

[0024] The first pipeline, the second pipeline and the gas source unit are sequentially communicated, and the pressure regulator is connected with the gas source unit;

[0025] The gas source unit is used for providing pressure-regulated gas;

[0026] The pressure regulator is used for adjusting the pressure output by the gas source unit under the adjustment instruction of the control module, and adjusting the negative pressure of the gas sample in the second pipeline.

[0027] In another aspect of the application, preferably, the adjustment module further comprises a Venturi unit;

[0028] The Venturi unit is arranged between the gas source unit and the second pipeline;

[0029] The Venturi unit comprises a converging section, a throat section and a diffuser section which are sequentially communicated, the converging section is connected with the second pipeline, and the diffuser section is connected with the gas source unit;

[0030] The Venturi unit is used for forming a local negative pressure area when the gas output by the gas source unit flows through, and adjusting the pressure and flow in the second pipeline by adjusting the flow state of the gas sample in the second pipeline.

[0031] In another aspect of the application, preferably, the gas detection module is based on the principle of zirconium oxide, and the gas detection module is arranged between the flow measurement module and the adjustment module;

[0032] The gas detection module is used for analyzing the composition of the passing gas sample, obtaining the NOx content in the gas sample, and obtaining the detection data. x

[0033] In another aspect of the application, preferably, the control module comprises a data receiving unit, an operation processing unit and an instruction generating unit;

[0034] The data receiving unit is used for obtaining the first pressure data of the first pressure detection unit and the second pressure data of the second pressure detection unit;

[0035] The operation processing unit is used for analyzing and processing the first pressure data and the second pressure data to obtain an operation processing result;

[0036] The instruction generating unit is used for generating a corresponding adjustment instruction according to the operation processing result and sending the adjustment instruction to the adjustment module.

[0037] In another aspect of the application, preferably, the operation processing result is calculated by using the following formula:

[0038] ;​

[0039] Wherein, Q represents an operation processing result, which is an actual flue gas flow; P1 represents first pressure data, P2 is second pressure data; d1 represents a first pipe diameter, d2 represents a second pipe diameter; p is a fluid density, which is a constant.

[0040] In another aspect of the present application, preferably, the generating corresponding adjustment instructions according to the operation processing result and sending to the adjustment module comprises:

[0041] When the actual flue gas flow is less than the corresponding preset target flow and the deviation is greater than the first threshold, a first adjustment instruction is generated, which comprises gradually increasing the pressure output by the adjustment module by a preset adjustment amount;

[0042] When the actual flue gas flow is greater than the corresponding preset target flow and the deviation is less than the second threshold, a second adjustment instruction is generated, which comprises gradually reducing the pressure output by the adjustment module by a preset adjustment amount;

[0043] When the actual flue gas flow is greater than the corresponding preset target flow and the deviation is less than the second threshold, a second adjustment instruction is generated, which comprises gradually reducing the pressure output by the adjustment module by a preset adjustment amount;

[0044] (Three) beneficial effects

[0045] The above technical solutions of the present application have the following beneficial technical effects:

[0046] The present application realizes fine management of different partition flue gas samples in the whole process of sampling, transmission and detection by setting the cooperative working mechanism among the sampling module, the flow measurement module, the adjustment module, the gas detection module and the control module. Through real-time detection and analysis of the pressure at different positions on the transmission path, and combining the judgment and operation ability of the control module, the output pressure of the gas source is dynamically adjusted, so that the different partition flue gas samples are always in a controlled state during the transmission process, and the different partition flue gas samples are synchronized to the corresponding gas detection module, effectively solving the problem of data distortion caused by asynchronous detection in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is the overall structure schematic diagram of one embodiment of the present application;

[0048] Figure 2 is the sampling module layout schematic diagram of one embodiment of the present application;

[0049] Figure 3 is the flue gas sample transmission path schematic diagram of one embodiment of the present application. DETAILED DESCRIPTION

[0050] The objectives, technical solutions and advantages of the present application will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. It should be understood that the description is merely exemplary and is not intended to limit the scope of the present application. In addition, in the following description, the description of well-known structures and techniques is omitted to avoid unnecessary confusion of the concept of the present application.

[0051] Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0052] In the description of the present application, it should be noted that the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0053] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0054] The present application will be described in more detail below with reference to the accompanying drawings. In each of the drawings, the same elements are denoted by similar reference numerals. Each part in the drawings is not drawn to scale for the sake of clarity.

[0055] Embodiment One

[0056] A NOx reduction device for a large flue x A partitioned synchronous measurement device, Figure 1 The overall structure of one embodiment of the present application is shown in the schematic diagram, as shown in the figure, comprising: a sampling module, a flow measurement module, an adjusting module, a gas detection module and a control module; Figure 1 The sampling module, the flow measurement module, the adjusting module and the gas detection module are connected with the control module in sequence;

[0057] The sampling module, the flow measurement module, the adjusting module and the gas detection module are connected with the control module in sequence;

[0058] The sampling module is used to sample flue gas from multiple zones of the main flue, obtain flue gas samples from the corresponding zones, and transmit the flue gas samples to the flow measurement module. The sampling module may include multiple sampling probes located at different zones of the main flue, each sampling probe being connected to a corresponding sampling pipeline, used to extract representative flue gas samples from the flue gas of each zone. Each sampling probe may be made of high-temperature resistant and corrosion-resistant materials, and preferably has an anti-clogging structure or a purging structure to avoid sampling instability caused by dust particles, high-temperature oil stains, etc. Specifically, in this embodiment, the sampling module includes several sampling probes, which are respectively located in each zone of the main flue, used to obtain flue gas samples from the corresponding zones; the sampling probes are respectively arranged at the locations of the zones divided along the cross-sectional direction inside the main flue, so that each sampling probe corresponds to a flue gas zone, thereby enabling the acquisition of representative flue gas samples from each zone. Each sampling probe is connected to the flow measurement module via a sampling pipeline to deliver the flue gas sample obtained from the corresponding zone to the flow measurement module. Each sampling probe is also connected to its respective flow measurement module via an independently configured sampling pipeline, forming multiple independent sampling channels corresponding to different zones. Figure 2 A schematic diagram of the sampling module layout according to an embodiment of the present invention is shown, as follows: Figure 2 As shown, the system includes nine sampling probes arranged in three three-dimensional groups to achieve comprehensive coverage and representative sampling of the gas distribution inside the flue. Three sampling probes are positioned at different heights on the same vertical plane, and three are positioned on the same horizontal plane, corresponding to the upper, middle, and lower parts of the flue, respectively, to collect flue gas samples at different height levels. Three more sampling probes are positioned along the width of the flue on the same horizontal plane, corresponding to the left, middle, and right sides, respectively, to collect flue gas samples from different lateral areas, thus achieving a comprehensive perception of the flue gas status across the large flue cross-section. The sampling pipe lengths of the probes on the same vertical plane are different, while the sampling pipe lengths of the probes on the same horizontal plane are the same. This layout can cover typical flue gas areas in different directions and locations within the large flue cross-section, fully reflecting the spatial non-uniformity of flue gas distribution. Furthermore, in this embodiment, the sampling probe is set to high-flow-rate sampling. High-flow-rate sampling is beneficial to improve the response speed. For example, the longest pipe of the transmission path is 6m, the inner diameter of the sampling pipe is about 15mm, and the air extraction rate is 60L / min. The flue gas sample can be delivered to the gas detection module in about 1 second, and the response speed is extremely fast.

[0059] Figure 3 A schematic diagram of the flue gas sample transport path according to an embodiment of the present invention is shown, as follows: Figure 3As shown, the flow measurement module is used to detect the pressure at different locations along the transport path of the flue gas sample and transmit the data to the control module. The flow measurement module is installed on each flue gas sample transport path, meaning each section of the flue gas sample corresponds to an independent flow measurement and pressure monitoring channel, thereby avoiding interference between different channels and ensuring the accuracy and comparability of the detection results. In this embodiment, the flow measurement module includes a first pressure detection unit, a second pressure detection unit, and a pressure regulation unit.

[0060] The first pressure detection unit, the pressure regulation unit, and the second pressure detection unit are connected in sequence; the three are connected in sequence along the transmission direction of the flue gas sample to form a closed-loop structure of initial measurement-adjustment-second measurement.

[0061] The first pressure detection unit is used to detect the initial pressure of the flue gas sample output by the sampling probe on the transmission path and transmits the detection result to the control module. The first pressure detection unit is located on the flue gas sample transmission path near the output end of the sampling probe. It is used to detect the pressure parameters of the flue gas sample when it enters the flow measurement module in the initial stage, reflecting the pressure level of each sampling path under the current transmission state. The first pressure detection unit can use a differential pressure sensor, pressure transmitter, or other high-precision pressure detection device. A sensor with an appropriate range and high-temperature resistance design can be selected according to the flue gas temperature and pressure level to ensure stable operation in high-temperature, dusty flue gas environments. The first pressure detection unit converts the detected first pressure data into an electrical signal in real time and transmits it to the control module for analysis and judgment.

[0062] The pressure regulating unit is used to regulate the pressure of the flue gas sample passing through the first pressure detection unit. The pressure regulating unit is disposed between the first pressure detection unit and the second pressure detection unit, and dynamically regulates the pressure of the flue gas sample passing through it through its own structure. In this embodiment, the pressure regulating unit includes a first pipe and a second pipe, and the diameter of the first pipe is larger than that of the second pipe.

[0063] The first pressure detection unit is located in the first pipe, and the second pressure detection unit is located in the second pipe. The flue gas sample moves from the first pipe to the second pipe. By guiding the flue gas sample through channels of different diameters, the pressure changes due to the change in cross-sectional area during transmission, thereby achieving dynamic adjustment of the flue gas sample pressure. The first pressure detection unit, located inside the first pipe, can detect the initial pressure of the flue gas sample as it passes through the large-diameter pipe. Due to the larger diameter of the first pipe and the lower internal fluid resistance, the flue gas sample flows relatively smoothly within this section, and the detected pressure value can more accurately reflect the pressure characteristics of the flue gas sample before significant throttling, providing reliable initial pressure reference data for the control module. After passing through the first pipe, the flue gas sample enters the second pipe. Because the diameter of the second pipe is smaller than that of the first pipe, while the flow rate remains relatively stable, the flow velocity of the flue gas sample within the smaller cross-section will increase accordingly, increasing flow resistance and creating a significant pressure change area inside the pipe. This structural throttling design enables active adjustment of the flue gas sample pressure, allowing the pressure of the flue gas sample to change after passing through the pressure adjustment unit.

[0064] The second pressure detection unit is used to detect the pressure of the flue gas sample after passing through the pressure regulating unit and transmit the detection result to the control module. The second pressure detection unit is located inside the second pipeline and is used to detect the actual pressure state of the flue gas sample after throttling and pressure regulation. By real-time detection of the pressure inside the second pipeline, the second pressure data after pressure regulation can be obtained, and this detection result is fed back to the control module. The control module can determine whether the current pressure regulation effect meets the control requirements of synchronous delivery and unified detection based on the pressure change between the first and second pressure detection units.

[0065] Furthermore, in this embodiment, the first and second pipes are made of corrosion-resistant 316L material with smooth inner walls. Because the entire process is heated at high temperature, the above setup can ensure that the flue gas components are not lost.

[0066] The control module generates adjustment commands based on the pressure at different locations and transmits them to the adjustment module. The control module may include a processor, a memory, and corresponding software programs. The processor pre-stores an algorithm model for synchronous control. The control module calculates and analyzes the pressure differences between the paths of each flue gas sample delivery route based on real-time pressure data, determines the current delivery status of each flue gas sample, and generates adjustment commands accordingly. These adjustment commands include adjustment ranges for differentiated control of different paths.

[0067] The adjustment module, based on the adjustment command, regulates the pressure of the transmission path to ensure that flue gas samples from different zones arrive at the gas detection module synchronously. The adjustment module may include actuators such as regulating valves, throttling devices, or variable frequency pumps installed on each sampling pipeline. According to the adjustment command issued by the control module, the adjustment module dynamically adjusts the pressure or flow rate in each sampling path, ensuring that flue gas samples from different zones achieve consistent or nearly consistent delivery times while maintaining representativeness and stability, thereby ensuring that flue gas samples from multiple zones arrive at the gas detection module synchronously. In this embodiment, the adjustment module includes a gas source unit and a pressure regulator.

[0068] The first pipe, the second pipe, and the gas source unit are connected in sequence, and the pressure regulator is connected to the gas source unit; the first pipe, the second pipe, and the gas source unit are connected in sequence, and the gas source unit is connected to the pressure regulator. By combining an external gas source with the internal pipe structure, the pressure state of the flue gas sample during transportation is dynamically adjusted.

[0069] The gas source unit is used to provide pressure-regulated gas. This gas can be air, inert gas, or other gases suitable for industrial flue gas environments that do not affect the analysis results of the detected components. The gas source unit may contain a gas storage tank, a pressure stabilizing device, or a filter and drying assembly to initially stabilize and process the gas pressure, ensuring the output gas has stable pressure and clean characteristics, and preventing impurities from interfering with the flue gas sample or affecting subsequent detection equipment.

[0070] The pressure regulator is used to adjust the pressure output by the gas source unit under the adjustment command of the control module, thereby adjusting the negative pressure of the air extraction in the second pipeline.

[0071] Furthermore, in this embodiment, the adjustment module also includes a Venturi unit;

[0072] The Venturi unit is disposed between the gas source unit and the second pipe; the Venturi unit includes a constriction section, a throat section and a diffusion section connected in sequence, the constriction section is connected to the second pipe and the diffusion section is connected to the gas source unit; the Venturi unit is used to form a local negative pressure zone when the gas output from the gas source unit flows through it, and to regulate the flow state of the flue gas sample in the second pipe by adjusting the negative pressure, thereby regulating the pressure and flow rate in the second pipe.

[0073] The Venturi unit's internal structure consists of a converging section, a throat section, and a diffuser section connected sequentially. The converging section connects to a second conduit, causing the flow cross-section of the flue gas sample or mixture from the second conduit to gradually decrease as it enters the Venturi unit. The throat section, with its smallest cross-section and shortest length, is the core area where significant velocity and pressure changes occur within the Venturi unit. The diffuser section connects to the gas source unit, and its cross-sectional area gradually increases, allowing the gas flow to gradually recover its pressure and velocity after passing through the smallest cross-section. This continuous cross-sectional change created by the above structure results in a significant local negative pressure effect in the throat region of the gas output from the gas source unit as it flows through the Venturi unit, based on fluid dynamics principles. When the gas output from the gas source unit enters the Venturi unit under the control of a pressure regulator, the velocity gradually increases and the pressure gradually decreases as the gas enters the converging section; in the throat section, the gas velocity reaches its peak, forming a local low-pressure or even negative-pressure region. This local negative pressure zone is connected to the second pipe, which can attract the flue gas sample in the second pipe, thereby changing the flow state of the flue gas sample in the second pipe and achieving the purpose of actively regulating the pressure and flow rate of the flue gas sample in the second pipe.

[0074] Furthermore, the Venturi unit is connected to the flue gas sample outlet, which helps to discharge the sampled flue gas.

[0075] The gas detection module is used to detect the composition of the conditioned flue gas sample and simultaneously obtain the NO content in the flue gas sample. x Detection data. The gas detection module can employ established detection methods such as chemiluminescence, infrared absorption, electrochemical analysis, or zirconium oxide analysis to analyze NO in simultaneously arriving flue gas samples from various zones. x Concentration detection. In this embodiment, the gas detection module is based on the zirconium oxide principle and is positioned between the flow measurement module and the regulation module. By placing the gas detection module between the flow measurement module and the regulation module, the influence of the gas source of the regulation module on the flue gas sample is avoided. The gas detection module is used to perform component analysis on the passing flue gas sample to obtain the NO concentration in the flue gas sample. x Detection data. Zirconia gas detection technology utilizes the characteristics of solid electrolyte zirconia—its sensitivity to changes in gas component concentration and stable output signal under high-temperature conditions—to form a potential difference or electrical signal change related to the concentration of the target component in the gas by constructing an electrochemical reaction system between the working electrode and the reference electrode under specific temperature conditions. Through the detection chamber structure and internal electrode materials, a stable gas contact environment is created at the zirconia sensing unit for the flue gas sample entering the detection module, thereby enabling the detection of NO in the flue gas sample. x The concentration of the components is measured in real time and continuously.

[0076] Furthermore, in this embodiment, the control module includes a data receiving unit, a processing unit, and an instruction generation unit;

[0077] The data receiving unit is used to acquire the first pressure data from the first pressure detection unit and the second pressure data from the second pressure detection unit; and input the pressure data to the processing unit in the form of a data stream or periodic sampling. The data receiving unit can be equipped with a data buffer and anti-interference processing mechanism to preprocess the acquired pressure signal, such as filtering, noise reduction, and outlier removal, to ensure the authenticity and reliability of the input data and provide a stable data foundation for subsequent calculation and analysis.

[0078] The calculation and processing unit is used to analyze and process the first pressure data and the second pressure data to obtain the calculation and processing results; the calculation and processing unit is used to perform comprehensive analysis and calculation on the first pressure data and the second pressure data, and calculate the actual flue gas flow rate based on the principles of fluid mechanics, combined with the pipe diameter and medium characteristic parameters. In this embodiment, the calculation and processing results are calculated using the following formula:

[0079] ;

[0080] Where Q represents the calculation result, which is the actual flue gas flow rate; P1 represents the first pressure data, and P2 represents the second pressure data; d1 represents the first pipe diameter, and d2 represents the second pipe diameter; ρ is the fluid density, a constant, used to correct for deviations caused by gas expansion under pressure difference. Through the above calculation model, the pressure difference and structural parameters before and after the pipe can be converted into stable and reliable actual flow parameters, achieving accurate quantification of the flue gas transport status.

[0081] The instruction generation unit generates corresponding adjustment instructions based on the calculation results and sends them to the adjustment module. Based on the deviation between the actual flue gas flow rate Q calculated by the calculation unit and the corresponding preset target flow rate, it generates targeted adjustment instructions to guide the adjustment module in dynamically controlling the flue gas sample pressure. This ensures that flue gas samples from each zone can be synchronously delivered and accurately detected by the gas detection module, including:

[0082] When the actual flue gas flow rate is less than the corresponding preset target flow rate and the deviation is greater than the first threshold, a first adjustment command is generated. The first adjustment command includes gradually increasing the pressure output by the adjustment module by a preset adjustment amount. The specific value of the first threshold is not limited here and can be 1%, 2%, 3%, etc. In this embodiment, the adjustment object is the output pressure of the pressure regulator, and the preset adjustment amount can be 0.001MPa, etc. By increasing the output pressure of the adjustment module, the negative pressure effect is enhanced, and the flow rate and flow of the flue gas sample in the second pipe are increased, so that it gradually approaches the target flow range. The gradual adjustment method can avoid the flow overshoot caused by a large adjustment at one time, while ensuring the stable response of the system.

[0083] When the actual flue gas flow rate is greater than the corresponding preset target flow rate and the deviation is less than the second threshold, a second adjustment command is generated. The second adjustment command includes gradually reducing the pressure output by the adjustment module by a preset adjustment amount. The specific value of the second threshold is not limited here, and it can be -1%, -2%, -3%, etc. By weakening the negative pressure effect, it is made to fall back to the target flow range.

[0084] When the actual flue gas flow rate deviates from the corresponding preset target flow rate by a factor greater than or equal to the second threshold and less than or equal to the first threshold, a third adjustment command is generated. The third adjustment command includes maintaining the current pressure output by the adjustment module to avoid system oscillations or pressure fluctuations caused by frequent adjustments.

[0085] Furthermore, in this embodiment, the preset target flow rate is related to the sampling tube length of the sampling probe. On the same vertical plane, the flue gas flow rate ratio corresponding to the sampling probe is the same as the sampling tube length ratio of the sampling probe.

[0086] Furthermore, in this embodiment, a correction module is also provided, which includes a temperature measurement unit, a pressure measurement unit, and a humidity measurement unit; the temperature measurement unit and the pressure measurement unit are located in the sampling module, and the humidity measurement unit can be located in the sampling module or connected to the humidity measurement value of the power plant;

[0087] The correction module is used to correct the calculation results, i.e., the actual flue gas flow rate. In actual operating conditions, flue gas samples contain water vapor, and actual measurements or calculations often need to use "dry flue gas" as a benchmark (e.g., for calculating pollutant emission concentrations). If water vapor is ignored, the pollutant concentration or volumetric flow rate in the dry flue gas may be overestimated. Gas volume is positively correlated with temperature. When the flue gas temperature increases, the thermal motion of molecules intensifies, the intermolecular distance increases, resulting in the same mass of flue gas occupying a larger volume, thus increasing the volumetric flow rate; conversely, when the temperature decreases, the volumetric flow rate decreases. Gas volume is negatively correlated with pressure. When the flue gas pressure increases, the intermolecular distance decreases, the same mass of flue gas occupies a smaller volume, thus decreasing the volumetric flow rate; when the pressure decreases, the volumetric flow rate increases.

[0088] Therefore, in this embodiment, the actual flue gas flow rate is corrected using the following formula:

[0089] ;

[0090] Among them: Q VO,干 The corrected flue gas flow rate is represented by Q; the actual flue gas flow rate is represented by T; the temperature measured by the temperature measurement unit is represented by P; and the pressure measured by the pressure measurement unit is represented by x. H2O This indicates that the humidity measurement unit detects humidity, T0=273.15 K, P0=101325 Pa (standard state parameters).

[0091] By employing the aforementioned correction module, real-time measurement of operating parameters such as temperature, pressure, and humidity is performed, and the actual flue gas flow rate is corrected based on standard state parameters. This achieves a standardized expression of flue gas flow rate, avoiding measurement deviations caused by fluctuations in water vapor content, temperature changes, or pressure variations in the flue gas sample. It also improves the comparability of different zones in synchronous measurements. This embodiment effectively eliminates the influence of humidity on the calculated results of dry flue gas flow rate and pollutant concentration, avoiding overestimation or underestimation of pollutant emission concentration and flow rate, and improving the accuracy and reliability of the measurement results.

[0092] This invention achieves refined management of flue gas samples from different zones throughout the entire sampling, transmission, and detection process by establishing a collaborative working mechanism among the sampling module, flow measurement module, adjustment module, gas detection module, and control module. Through real-time detection and analysis of pressure at different locations along the transmission path, combined with the judgment and calculation capabilities of the control module, the gas source output pressure is dynamically adjusted, ensuring that flue gas samples from different zones remain under control throughout the transmission process. This ensures that flue gas samples from different zones reach their corresponding gas detection modules synchronously, effectively solving the problem of data distortion caused by asynchronous detection in existing technologies. Furthermore, this invention eliminates the need for a filter module, avoiding pipeline blockage caused by dust accumulation in the filter element, and is essentially maintenance-free.

[0093] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

[0094] The present invention has been described above with reference to embodiments thereof. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

[0095] Although embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and modifications can be made to the embodiments of the present invention without departing from the spirit and scope of the invention.

[0096] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A NOx for use in large flues x The partitioned synchronous measurement device is characterized in that, include: Sampling module, flow measurement module, regulation module, gas detection module, and control module; The sampling module, flow measurement module, adjustment module, and gas detection module are respectively connected to the control module; The sampling module is used to sample the flue gas from multiple zones of the main flue, obtain flue gas samples from the corresponding zones, and transmit the flue gas samples to the flow measurement module. The flow measurement module is used to detect the pressure at different locations along the transmission path of the flue gas sample and transmit the data to the control module. The control module generates adjustment commands based on the pressure at different locations and transmits them to the adjustment module. The adjustment module adjusts the pressure of the transmission path based on the adjustment command, so that flue gas samples from different zones arrive at the corresponding gas detection modules synchronously. The gas detection module is used to detect the composition of the flue gas sample and simultaneously obtain the NO content in the flue gas sample. x Test data; The sampling module includes several sampling probes, which are respectively set in each section of the main flue and are used to obtain flue gas samples from the corresponding sections. Each of the sampling probes is connected to the flow measurement module via a sampling pipeline to deliver the flue gas sample obtained from the corresponding zone to the flow measurement module; The flow measurement module includes a first pressure detection unit, a second pressure detection unit, and a pressure regulation unit; The first pressure detection unit, the pressure regulation unit, and the second pressure detection unit are connected in sequence. The first pressure detection unit is used to detect the initial pressure of the flue gas sample output by the sampling probe on the transmission path, and transmit the detection result to the control module; The pressure regulating unit is used to regulate the pressure of the flue gas sample passing through the first pressure detection unit. The second pressure detection unit is used to detect the pressure of the flue gas sample after passing through the pressure regulating unit, and transmit the detection result to the control module; The pressure regulating unit includes a first pipe and a second pipe, wherein the diameter of the first pipe is larger than that of the second pipe. The first pressure detection unit is disposed in the first pipe, the second pressure detection unit is disposed in the second pipe, and the flue gas sample moves from the first pipe to the second pipe; The regulating module includes a gas source unit and a pressure regulator; The first pipe, the second pipe, and the gas source unit are connected in sequence, and the pressure regulator is connected to the gas source unit. The gas source unit is used to provide pressure-regulated gas; The pressure regulator is used to adjust the pressure output by the gas source unit under the adjustment command of the control module, thereby adjusting the negative pressure of the air extraction in the second pipeline.

2. The NO3- for large flues according to claim 1 x The partitioned synchronous measurement device is characterized in that, The adjustment module also includes a Venturi unit; The Venturi unit is disposed between the gas source unit and the second pipeline; The Venturi unit includes a constriction section, a throat section, and a diffuser section connected in sequence. The constriction section is connected to the second pipe, and the diffuser section is connected to the gas source unit. The Venturi unit is used to form a local negative pressure zone when the gas output from the gas source unit flows through it. The negative pressure is used to regulate the flow state of the flue gas sample in the second pipe, thereby regulating the pressure and flow rate in the second pipe.

3. The NO3- for large flues according to claim 2 x The partitioned synchronous measurement device is characterized in that, The gas detection module is based on the zirconium oxide principle and is located between the flow measurement module and the regulation module; The gas detection module is used to perform component analysis on the passing flue gas sample to obtain the NO content in the flue gas sample. x Test data.

4. The NO3- for large flues according to claim 3 x The partitioned synchronous measurement device is characterized in that, The control module includes a data receiving unit, a processing unit, and an instruction generation unit; The data receiving unit is used to acquire the first pressure data of the first pressure detection unit and the second pressure data of the second pressure detection unit. The calculation and processing unit is used to analyze and process the first pressure data and the second pressure data to obtain the calculation and processing results; The instruction generation unit is used to generate corresponding adjustment instructions based on the calculation results and send them to the adjustment module.

5. The NO3- for large flues according to claim 4 x The partitioned synchronous measurement device is characterized in that, The result of the calculation is calculated using the following formula: ； Where Q represents the result of the calculation, which is the actual flue gas flow rate; P1 represents the first pressure data, P2 represents the second pressure data; d1 represents the first pipe diameter, d2 represents the second pipe diameter; and ρ represents the fluid density, which is a constant.

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