Online monitoring device and monitoring method for inorganic elements in flue gas

Abstract

The invention belongs to the technical field of environment monitoring, and discloses an on-line monitoring device for inorganic elements in flue gas, the on-line monitoring device comprises a bypass pipeline and a detection module, the bypass pipeline is provided with a gas inlet, a gas outlet and an enrichment passage, the gas inlet and the gas outlet are respectively arranged at the upstream and downstream of a flue and are communicated with flue gas, and the gas inlet is provided with a gas pump; the enrichment passage is at least one part of the bypass pipeline, the sectional area of the enrichment passage in the direction perpendicular to the flue gas flowing direction is smaller than the sectional area of the bypass pipeline in the direction perpendicular to the flue gas flowing direction, and the enrichment passage is used for quickly enriching particulate matters in the flue dust; the detection module rapidly measures the content of the target inorganic element in the particulate matter in the enrichment passage, so that introduction of an additional sampling pipeline and a detection chamber is avoided, particulate matter mass loss caused by pipeline adsorption is reduced, the accuracy is improved, and meanwhile, the time resolution of the detection process is improved.

Description

Technical Field

[0001] This application belongs to the technical field of environmental monitoring. Specifically, it relates to an on-line monitoring device and method for inorganic elements in flue gas. Background Art

[0002] The flue gas generated by combustion operations usually contains various elements, such as inorganic elements without carbon like potassium, sodium, calcium, magnesium, aluminum, silicon, iron, manganese, copper, zinc, lead, cadmium, chromium, arsenic, etc. The content of these elements in the flue gas may vary depending on the type of fuel, combustion conditions, and flue gas treatment processes. These common inorganic elements in the flue gas, especially heavy metal elements such as lead, cadmium, chromium, arsenic, etc., are directly or potentially polluting to the environment.

[0004] Currently, the common real-time monitoring methods for particulate matter containing inorganic elements in flue gas are as follows: mainly focused on the monitoring of gaseous mercury, which is measured by atomic absorption method; various methods for multi-element measurement, including X-ray fluorescence spectrometry (XRF), inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma-mass spectrometry (ICP-MS), etc. The currently common detection method is the fluorescence analysis method based on an XRF analyzer, and its analysis process is simple; the devices using ICP-AES or ICP-MS methods are complex in themselves and require sample digestion for analysis, which is not suitable for real-time on-line analysis.

[0005] However, the XRF method also has problems such as sample loss caused by sampling and low resolution in on-line analysis, and it cannot balance the real-time nature and accuracy of detection. For example, the on-line detection device for heavy metal content in flue gas disclosed in Chinese Patent CN103822934A filters gaseous heavy metals in the flue gas by setting a filter membrane support in the dust collection chamber and measures the heavy metals on the active filter membrane using XRF. In this process, additional sampling pipelines such as sampling guns and dust collection chambers are introduced, causing some substances to be adsorbed; the rural household stove emissions air pollutant sampling and monitoring system disclosed in Chinese Patent CN112577787B reduces the loss of flue gas during sampling by partially entering the first-stage dilution chamber in the dilution tube and partially discharging through the exhaust pipe and continuously heating the sampling gun, but it is still detected in an independent analytical instrument subsequently, resulting in a reduction in the time resolution of the entire system. As can be seen from the above, it is difficult to balance the detection quality and time in existing detection equipment.

[0006] Therefore, an improved real-time monitoring device and method for inorganic elements in flue gas are needed to meet the requirements of rapid and continuous detection and analysis and ensure good detection quality. Summary of the Invention

[0007] To solve the problems existing in the prior art, the purpose of the present application is to provide an on-line monitoring device for inorganic elements in flue gas. The device is connected to the flue along the flue gas discharge direction, introduces a flue gas detection bypass into the flue, and the inorganic particulate matter in the flue gas is directly captured and enriched in the detection bypass, and the content of various elements of the inorganic particulate matter is directly measured by an XRF-based detection module, avoiding the adsorption loss of inorganic element samples during the collection process and ensuring the uniformity of the samples.

[0008] Specifically, the present application relates to the following aspects:

[0009] According to one aspect of the present application, there is provided an on-line monitoring device for inorganic elements in flue gas, including: a bypass pipeline and a detection module; the bypass pipeline has an air inlet, an air outlet and an enrichment passage, the air inlet and the air outlet are respectively arranged at the upstream and downstream of the flue, the bypass pipeline is in gas communication with the flue gas through the air inlet and the air outlet, and an air pump is configured at the air inlet; the enrichment passage is at least a part of the bypass pipeline, and the cross-sectional area of the enrichment passage in the cross-section perpendicular to the flue gas flow direction is smaller than the cross-sectional area of the bypass pipeline in the cross-section perpendicular to the flue gas flow direction, so that the gas path of the flue gas in the enrichment passage becomes narrower and the flow rate increases; the shape of the enrichment passage is a dumbbell groove.

[0010] According to some embodiments of the present application, the bypass pipeline further includes: a breathable flat plate and a filter membrane conveyor belt; the breathable flat plate is arranged in the enrichment passage at a certain angle along the flue gas flow direction in the enrichment passage for fixing the filter membrane conveyor belt; the filter membrane conveyor belt is used for intercepting particulate matter samples in the flue gas, and both ends of the filter membrane conveyor belt are rollers or drums for conveying the filter membrane on the filter membrane conveyor belt into or out of the detection area; the material of the filter membrane is PTFE; preferably, the ratio of the length of the bypass pipeline along the flue gas flow direction to the cross-sectional width or diameter of the bypass pipeline in the cross-section perpendicular to the flue gas flow direction ranges from 6:1 to 3:1; preferably, the ratio of the length of the enrichment passage along the flue gas flow direction to the cross-sectional width or diameter of the enrichment passage in the cross-section perpendicular to the flue gas flow direction ranges from 2:1 to 5:3.

[0011] According to some embodiments of the present application, the enrichment passage has an upper gas path wall at the upper end and a lower gas path wall at the lower end, and the projected parts of the upper gas path wall and the lower gas path wall in the direction perpendicular to the flue gas flow direction in the enrichment passage overlap to change the flow direction of the flue gas in the enrichment passage.

[0012] According to some embodiments of the present application, the upper gas path wall and the lower gas path wall are respectively located on one side of the upper end and the other side of the lower end of the enrichment passage, and the projected parts in the direction perpendicular to the flue gas flow direction in the enrichment passage overlap.

[0013] According to some embodiments of the present application, the breathable flat plate is disposed in the enrichment passage parallel to the flue gas flow direction; the projection of the breathable flat plate in the direction perpendicular to the flue gas flow direction in the enrichment passage is located in the overlapping area of the projections of the upper wall and the lower wall of the gas path in the direction perpendicular to the flue gas flow direction in the enrichment passage.

[0014] According to some embodiments of the present application, the bypass pipe further includes a lens window; the lens window is disposed on the wall of the bypass pipe, and the detection module measures the elemental content of the particulate matter in the enrichment passage through the lens window; the material of the lens window is beryllium.

[0015] According to some embodiments of the present application, the detection module includes a detection source, a fluorescence detector, and a data analysis unit; the detection source emits primary X-rays and irradiates the particulate matter sample in the flue gas through the lens window; the fluorescence detector receives the characteristic X-rays released by the particulate matter sample in the flue gas through the lens window to obtain the X-ray fluorescence energy spectrum of the particulate matter; the data analysis unit calculates the X-ray fluorescence intensity of the target element in the particulate matter based on the X-ray fluorescence energy spectrum to obtain the content of the target element.

[0016] According to some embodiments of the present application, the length range of the lens window along the flue gas flow direction is 20 cm to 35 cm; the angle range between the primary X-ray emission position of the detection source and the plane where the filter membrane is located is 50° to 65°; the angle range between the characteristic X-ray reception position of the fluorescence detector and the plane where the filter membrane is located is 40° to 55°.

[0017] According to some embodiments of the present application, the air inlet and the air outlet are connected to the flue wall through flanges.

[0018] According to another aspect of the present application, there is also provided an on-line monitoring method for inorganic elements in flue gas in a flue, including: a collection step of using a gas pump to extract the flue gas to be measured in the flue into a detection pipeline, enriching or intercepting the particulate matter sample containing the target inorganic element in the flue gas to be measured within a specified time, and allowing the remaining flue gas to flow back into the flue through the detection pipeline and be discharged along with the flue; a measurement step of emitting an X-ray beam to the obtained particulate matter sample through a measurement module, the particulate matter sample receiving the irradiation of the X-ray beam and emitting characteristic X-ray fluorescence radiation of the target inorganic element, and the measurement module receiving the characteristic X-ray fluorescence radiation of the target inorganic element and processing it to obtain an X-ray fluorescence energy spectrum; a calculation step of a calculation module processing the X-ray fluorescence energy spectrum by using a full-spectrum fitting method or a specific peak area integration method to obtain the characteristic X-ray fluorescence intensity of the target inorganic element in the particulate matter sample, and determining the concentration of the target inorganic element according to the relationship between the characteristic X-ray fluorescence intensity and the element content; a reset step of removing the particulate matter sample in the detection pipeline and resetting the working state of the measurement module; repeating the collection step, the measurement step, the calculation step, and the reset step to continuously on-line monitor the concentration of the target inorganic element in the flue gas to be measured in the flue.

[0019] The monitoring device for inorganic elements in flue gas provided by this application is connected to the pipeline of the discharged flue gas in a bypass form, without the need to specially collect inorganic particulate samples using a sampling pipeline and perform operations such as enrichment or dilution, reducing pipeline losses and sampling time; by setting an enrichment path in the bypass pipeline, such as setting an enrichment path in the shape of a dumbbell groove, a good and rapid enrichment effect on fine particulate matter in the gas is achieved, enabling the particulate samples to be evenly distributed on the filter membrane; a lens window is set on the wall of the bypass and allows the exchange of X-ray light information between the detection module and the particulate sample, realizing non-contact real-time measurement of inorganic elements in the particulate matter, and further improving the time resolution and accuracy of detection. On this basis, adjusting the size and shape of the enrichment path, changing the material of the lens window, and optimizing the detection principle of the detection module can also improve the real-time detection performance of the monitoring device for inorganic elements in flue gas to varying degrees, to help relevant technical personnel continuously monitor and optimize flue gas emissions and ensure environmental cleanliness and human health. Description of the Drawings

[0020] Figure 1 The overall schematic diagram of the monitoring device for inorganic elements in flue gas according to an embodiment of this application is illustrated.

[0021] Figure 2A The schematic diagram of an example of the detection area of the monitoring device for inorganic elements in flue gas according to an embodiment of this application is illustrated.

[0022] Figure 2B The schematic diagram of another example of the detection area of the monitoring device for inorganic elements in flue gas according to an embodiment of this application is illustrated.

[0023] Figure 3A The structural block diagram of an example of the monitoring device for inorganic elements in flue gas according to an embodiment of this application is illustrated.

[0024] Figure 3B The structural block diagram of another example of the monitoring device for inorganic elements in flue gas according to an embodiment of this application is illustrated.

[0025] Figure 4 The schematic diagram of the detection module of the monitoring device for inorganic elements in flue gas according to an embodiment of this application is illustrated.

[0026] Figure 5 The flowchart of the on-line monitoring method for inorganic elements in flue gas in a flue according to an embodiment of this application is illustrated.

[0027] Reference Signs

[0028] 1 - Bypass Pipeline 2 - Lens Window 3 - Detection Module 4 - Flue

[0029] 10 - Intake port 11 - Outlet port 12 - Permeable flat plate 13 - Air pump

[0030] 30 - Detection source 31 - Fluorescence detector 120 - Filter membrane conveyor belt

[0031] 130 - Upper wall of gas path 140 - Lower wall of gas path Detailed implementation manners

[0032] The present application will be further described below in conjunction with embodiments. It should be understood that the embodiments are only used to further illustrate and explain the present application, and are not used to limit the present application.

[0033] Unless otherwise defined, the technical and scientific terms in this specification have the same meanings as those commonly understood by those skilled in the art. Although methods and materials similar or identical to those described herein can be used in experiments or practical applications, the materials and methods are still described below. In case of conflict, the present specification including the definitions therein shall prevail. Additionally, the materials, methods, and examples are for illustrative purposes only and are not restrictive. The present application will be further described below in conjunction with specific embodiments, but is not used to limit the scope of the present application.

[0034] Overview of the application

[0035] As described above, in the field of flue gas detection, the currently common method is to use a detection device based on the XRF principle, which has a simple and efficient analysis process, low application cost, and wide application. However, in the current method of online analysis using the XRF principle, there are still the following disadvantages: (1) Particulates in the flue gas are adsorbed by the sampling pipeline, resulting in mass loss of the particulates, which may cause the measurement results to be distorted and lower than the true value; (2) The sampling pipeline for particulates in the flue gas is too long, resulting in a long analysis cycle and unsatisfactory online real-time monitoring effect; (3) The uniformity of the samples obtained through the sampling pipeline is poor, which affects the detection accuracy of XRF-related instruments.

[0036] In addition, when using methods such as ICP-AES / ICP-MS or absorption liquid, there will also be problems such as incomplete absorption of the absorption liquid or complex digestion processes, resulting in a long analysis cycle. To address the problem of particulates being adsorbed by the sampling pipeline, it is possible to consider reducing the pipeline length or optimizing the pipeline material and the environment where the pipeline is located. It is possible to consider setting the sampling pipeline near the flue gas collection position to minimize the distance between the particulate collection position, enrichment position, and detection position, thereby reducing the loss of particulates during the movement of the gas; in addition, the sampling pipeline can also be heated to keep it at a high temperature to prevent particulates from contacting the pipe wall or being adsorbed due to condensation when near the pipe wall; or increasing the flue gas sampling rate to reduce the turbulence of the flue gas and prompt the particulates to reach the collection area faster for interception and enrichment.

[0037] These methods can all reduce the loss of particulate matter and the analysis cycle to a certain extent. However, during the XRF detection process, particulate matter will still be lost during the process of being collected and sent to the detection component, and it cannot be guaranteed that the particulate matter is evenly distributed during the process of being adsorbed onto the collection component. For example, when the air flow velocity is relatively fast, the air flow velocity near the pipe wall of the sampling tube is slower, and the air flow velocity at the center of the pipe is faster. Especially at positions such as the elbows and diameter-changing parts of the pipe, this difference will cause the distribution of particulate matter in the pipe to be sparse at the center and dense at the pipe wall, thus affecting the uniformity of sampling. As a result, some particulate matter near the pipe wall cannot be well irradiated by X-rays after being collected, and the obtained energy spectrum diagram is inaccurate.

[0038] Therefore, the present application provides a monitoring device for inorganic elements in flue gas, which includes a bypass pipeline and a detection module. The bypass pipeline has an air inlet and an air outlet, both of which can be directly connected to a flue where flue gas flows, such as an industrial chimney or a household flue gas pipeline, etc., in a certain way to serve as a bypass pipeline of the flue. An air pump is arranged at the air inlet to introduce more flue gas into this bypass pipeline; a breathable flat plate and a filter membrane conveyor belt are also arranged in the bypass pipeline. The breathable flat plate is arranged in the bypass pipeline along a direction forming a certain angle with the flowing direction of the flue gas in the bypass pipeline, so as to fix the filter membrane conveyor belt on its surface. The filter membrane with particulate matter fixed on the filter membrane conveyor belt can be transferred by the conveyor belt and replaced with a new filter membrane.

[0039] In addition, the monitoring device for inorganic elements in flue gas provided by the present application has an enrichment passage in the bypass pipeline, which has a smaller cross-sectional area perpendicular to the flowing direction of the flue gas compared with other parts of the bypass pipeline, so as to increase the flow velocity of the flue gas therein and reduce the unit flow volume. The breathable flat plate and the filter membrane conveyor belt can be arranged in the enrichment passage; and, the bypass pipeline of the monitoring device for inorganic elements in flue gas provided by the present application also has a lens window on the outer wall of the enrichment passage. At the position of the lens window, external X-rays can enter the pipe and irradiate the enriched particulate matter, and the X-rays emitted by the particulate matter can also leave the bypass pipeline through the lens window and be captured.

[0040] Furthermore, the present application further includes a detection module, which uses a detection source to emit primary X-rays and irradiate the particulate matter through the lens window; uses a fluorescence detector to receive the characteristic X-rays released by the particulate matter irradiated by the X-rays through the lens window to obtain the X-ray fluorescence energy spectrum of the particulate matter; and uses a data analysis unit to calculate the X-ray fluorescence intensity of the target inorganic element in the particulate matter based on the obtained X-ray fluorescence energy spectrum to obtain the content of the target element.

[0041] In this way, the device of the present application does not require an additional sampling pipeline. Instead, it is equivalent to directly diverting a branch, i.e., a bypass pipeline, from the flue gas discharge flue to collect and enrich the particulate matter in the flue gas, which can avoid the problem of too long sampling path of the existing detection device. In addition, since both the head and the tail of the bypass pipeline are connected to the gas path of the flue gas pipeline, its internal temperature and gas phase fluidity are basically the same as those of the flue gas pipeline, effectively reducing the adsorption problem of particulate matter by the additional sampling pipeline caused by environmental parameters and material heterogeneity. Moreover, by setting a lens window on the wall of the bypass pipeline and using the interaction between the detection module and the particulate matter therein, it is equivalent to directly setting the XRF fluorescence detection chamber in the sampling pipeline without the need to separately set up a detection space, which can avoid any form of loss of the enriched particulate matter sample to improve the detection accuracy and shorten the element analysis time of the device. Finally, through the appropriate pipe diameter ratio of the bypass pipeline, the relative positions of the inlet and outlet of the enrichment passage, and the angle and length of the filter membrane conveyor belt relative to the flue gas flow direction, it is also possible to ensure the uniformity of the distribution of the collected particulate matter on the filter membrane and avoid the accumulation of particulate matter to improve the accuracy of fluorescence detection.

[0042] After introducing the basic principle of the present application, various non-limiting embodiments of the present application will be specifically introduced below with reference to the accompanying drawings.

[0043] Exemplary device

[0044] Figures 1 - 2B The structural schematic diagram of the monitoring device for inorganic elements in flue gas according to an embodiment of the present application is illustrated.

[0045] As Figures 1 - 2B shown, the monitoring device for inorganic elements in flue gas according to an embodiment of the present application includes a bypass pipeline 1 and a detection module 3.

[0046] The bypass pipeline 1 has an enrichment passage for enriching particulate matter in the flue gas. An air-permeable plate 12 can be further arranged in the enrichment passage. One side surface of the air-permeable plate 12 has a filter membrane conveyor belt 120, and the filter membrane conveyor belt 120 is essentially a filter membrane that can be controlled to move along one side surface of the air-permeable plate 12. The bypass pipeline 1 has an air inlet 10 connected to the upstream of the flue 4 and an air outlet 11 connected to the downstream of the flue 4. The air inlet 10 and the air outlet 11 are in gas path communication with the flue 4. An air pump 13 is configured at the air inlet 10 for pumping flue gas into the pipeline.

[0047] Furthermore, the air-permeable plate 12 can be arranged in the bypass pipeline 1 along a direction at a certain angle to the flue gas flow direction in the bypass pipeline 1, for example Figure 2AIt is arranged parallel to the flue gas flow direction in the example. The filter membrane conveyor belt 120 fixed on one side surface of the air-permeable flat plate 12 can extend to both sides outside the air-permeable flat plate 12, and pulleys or rollers are arranged at both ends. The pulleys or rollers can be driven by a motor to drive the filter membrane conveyor belt 120 to translate on one side surface of the air-permeable flat plate 12; the pulleys, rollers and / or the motor can be arranged in the non-detection area of the bypass duct 1 (that is, the area not affected by the detection source 30 of the detection module 3 and not detectable by the fluorescence detector 31), such as the area behind the other side surface of the air-permeable flat plate 12 or the area outside the enrichment passage. Therefore, the filter membrane conveyor belt 120 can be driven on the air-permeable flat plate 12 to replace in real time the filter membrane on the filter membrane conveyor belt 120 that is blocked due to more intercepted particulate matter in the detection area, ensuring continuous detection sensitivity.

[0048] Generally, when detecting the types and concentrations of particulate matter in the flue duct 4, a sampling tube or a sampling gun is usually selected to regularly extract and sample the gas from the main gas flow position in the flue duct 4. Due to the strong fluidity of the flue gas and the small intake port of the sampling gun, the time of this sampling method is relatively long, and the particulate matter it absorbs will also show different components or contents due to the influence of the sampling gun position. Therefore, the monitoring device for inorganic elements in the flue gas according to the embodiment of the present application provides a bypass duct 1. The inside of the bypass duct 1 has a certain pipe diameter ratio. The intake port 10 and the outlet port 11 can both communicate with the inner wall of the flue duct 4 along the flue gas flow direction. The flue gas entering the bypass duct 1 can flow naturally. Therefore, the flue gas in the duct is more evenly distributed than the sampled gas captured by the sampling gun, and can better represent the true level of the soot concentration in the flue duct 4.

[0049] Among them, the connection methods of the intake port 10 and the outlet port 11 to the flue duct 4 can be various, specifically depending on the size of the flue duct 4. For example, when the monitoring device for inorganic elements in the flue gas according to the embodiment of the present application needs to be connected to an industrial chimney for real-time continuous monitoring, a flange can be used for connection, that is, flange connection. Flanges (hereinafter referred to as flanges) are respectively arranged at the connection of the chimney and the intake port 10 and the outlet port 11. A gasket can be placed between the flanges to improve the airtight performance, and then the flanges of the intake port 10 and the outlet port 11 are respectively connected to the corresponding flanges at the connection of the chimney by means of bolt fitting or welding, so that the bypass duct 1 forms a stable flue gas circulation bypass in the chimney. Technicians can also select a suitable connection method for the bypass duct 1 and the flue duct 4 according to the actual situation. For example, when the size of the flue duct 4 where the flue gas to be measured is located is small, the bypass duct 1 can also be connected to it through a ball valve or the like.

[0050] In this way, the bypass duct 1 as a whole serves as a branch of the flue duct 4, maintaining the same gas path as the flue duct 4 and receiving the same-source flue gas, so that the composition, fluidity, etc. of the flue gas flowing through the bypass duct 1 are consistent with those of the original duct. Therefore, when collecting the flue gas particulate sample, it is equivalent to directly collecting in the flue duct 4 rather than through a sampling pipeline, which can avoid the influence caused by the sampling pipeline, such as particulate adsorption or sample dilution. In some embodiments, an air pump 13 can also be arranged near the air inlet 10 to actively draw the flue gas in the flue duct 4 into the bypass duct 1, increasing the intake air volume while ensuring that the flue gas flow rate in the bypass duct 1 does not change significantly, thereby improving the enrichment or interception efficiency of the particulate matter.

[0051] Moreover, an appropriate pipe diameter ratio can be configured for the bypass duct 1 based on the size of the flue duct 4. It can be understood that if the diameter of the flue duct 4 (or the width perpendicular to the flue gas flow direction) is large while the inner diameter of the bypass duct 1 (or the width perpendicular to the flue gas flow direction) is too small, it will be difficult for the flue gas to enter the bypass; conversely, if the inner diameter of the entire part of the bypass duct 1 (or the width perpendicular to the flue gas flow direction) is very large, it will increase its manufacturing cost additionally, and also pose challenges to the effective sealed connection of the air inlet 10, the air outlet 11 and the flue duct 4, and may increase potential hazards such as flue gas leakage. Therefore, the monitoring device for inorganic elements in flue gas according to the embodiments of the present application provides a general pipe diameter setting scheme for the bypass duct 1 of various chimneys.

[0052] Specifically, a certain ratio needs to be maintained between the flue gas flow length and the cross-sectional width of the bypass duct 1 (or the radial length when the duct is cylindrical), so that the flue gas can flow through it at an appropriate flow rate under the action of the air pump 13, avoiding the influence on the detection accuracy due to too fast flow rate or too small flow rate. Therefore, the present application proposes some preferred embodiments, setting the ratio of the length of the bypass duct 1 along the flue gas flow direction to its cross-sectional width or cross-sectional diameter perpendicular to the flue gas flow direction between 6:1 and 3:1. When the bypass duct 1 itself needs to be sized according to the size of the flue duct 4, the pipe diameter ratio remains constant to make the flue gas flow evenly. Further, it can be more preferably 4:1.

[0053] In some examples, when used to connect to a chimney with a larger capacity, the length of the bypass duct 1 can be 800 mm, and this length can be suitable as a bypass for most industrial exhaust chimneys, such as tower chimneys, boiler chimneys or combined chimneys, etc.; correspondingly, the cross-sectional width or cross-sectional diameter of the bypass duct 1 perpendicular to the flue gas flow direction can be 200 mm. In this way, the pipe diameter ratio of the entire bypass duct 1 remains at 4:1. After introducing flue gas for a period of time and then stopping the operation of the air pump 13, the flue gas flow rate in the duct slows down significantly. At this time, the XRF-based detection module 3 can be used for rapid detection.

[0054] Furthermore, when considering the case of enriched particulate matter, the ratio of the length of the enrichment path along the flue gas flow direction to its cross-sectional width or cross-sectional diameter perpendicular to the flue gas flow direction also has a preferred range. According to some preferred embodiments of the present application, the pipe diameter ratio of the enrichment path can be between 2:1 and 5:3; further, it is more preferably 5:3. It can be understood that the cross-sectional width (or cross-sectional diameter) of the enrichment channel is usually smaller than that of the bypass duct 1. The higher pipe diameter ratio is due to the smaller length ratio of itself, avoiding too small flue gas flow rate therein, and at the same time facilitating the further setting of the breathable flat plate 12, the filter membrane conveyor belt 120 and the corresponding components therein. For example, in the bypass duct 1 connected to the industrial chimney in the above preferred embodiment, the length of the enrichment path can be set to 50 mm, the cross-sectional width or cross-sectional diameter of the enrichment path perpendicular to the flue gas flow direction is 30 mm, and the pipe diameter ratio of the enrichment path is maintained at 5:3, increasing the density of particulate matter passing through therein within a certain period of time.

[0055] It should be noted that this preferred pipe diameter ratio of the enrichment path can be based on the preferred pipe diameter ratio of the bypass duct 1 to achieve better enrichment function and detection uniformity; it can also be independent of the preferred pipe diameter ratio of the bypass duct 1 and is itself a preferred scheme for efficient particulate matter enrichment. When technicians need to appropriately increase or decrease the size of the enrichment path according to the actual use situation, the preferred pipe diameter ratio can still be used without considering the change of the bypass duct 1. In particular, in the above example, the preferred pipe diameter ratio of the enrichment path can also well adapt to provide a good detection space for the detection source 30 and the fluorescence detector 31, avoiding the difficulty of the detection module 3 to cooperate with the bypass duct 1.

[0056] In actual combustion operations, monitoring is not only required when the pollution degree of the flue gas may exceed the standard. The continuous monitoring process can also occur in the long-term monitoring or research experiments of normal flue gas emissions. In some cases, the content of specific particulate matter in the flue gas itself, such as particulate matter containing certain inorganic heavy metal elements, is relatively low. After part of the flue gas enters the bypass duct 1, the low content makes it difficult for the filter membrane on the filter membrane conveyor belt 120 to intercept a sufficient amount of particulate matter for effective XRF detection in a short time, which will affect the timeliness and accuracy of the monitoring of inorganic elements in the flue gas. The detection method can be considered to be changed, such as changing the ED-XRF detection tool to a more sensitive WD-XRF detection tool, but this will significantly increase the economic and time costs of detection. Therefore, it is necessary to use the bypass duct 1 to enrich the particulate matter therein to improve the good adaptability of the particulate matter sample to the ED-XRF method.

[0057] In some preferred embodiments, continue as Figure 1As shown, when the enrichment passage is in the shape of a dumbbell groove, its cross-sectional area in the direction perpendicular to the flue gas flow is smaller than that of other parts of the bypass duct 1 in the direction perpendicular to the flue gas flow. As a result, when the flue gas flows into the enrichment passage, due to the narrowing of the gas path and the increase in flow velocity, the volumetric flow density of the flue gas increases significantly, which can increase the particulate density in the passage within a certain period of time. In addition, the breathable flat plate 12 with the filter membrane conveyor belt 120 can be further arranged in the enrichment passage. In the same period of time, the density of the flue gas flowing through the filter membrane conveyor belt 120 increases significantly and it carries more particulates, and the filter membrane can efficiently intercept and enrich these particulates. In addition, the upper and lower ends of the dumbbell groove can be naturally joined to other parts of the bypass duct 1, reducing gas path leakage.

[0058] Specifically, for flue gas with general or high-concentration soot, the enrichment passage can achieve good particulate enrichment without setting the breathable flat plate 12. While in the case where the flue duct 4 itself is relatively clean and the soot density is low, the breathable flat plate 12 and the filter membrane conveyor belt 120 thereon can be further arranged in the enrichment passage. It can be understood that when the soot concentration in the chimney is lower than 500 mg / m 3 ³, the sensitivity of the XRF detection equipment to particulates in the flue gas will decrease significantly. At this time, it is necessary to introduce a filter membrane to intercept particulates for further enrichment so that the detection can be effectively carried out. In practical applications, the approximate concentration of soot in the chimney is usually not known. When the soot concentration in the chimney is not known in advance, a sample can be taken from the chimney in advance for preliminary measurement of the soot concentration. Combining with the on-site working conditions, when the soot is lower than the above threshold, a filter membrane can be further introduced into the enrichment channel.

[0059] In some embodiments, the breathable flat plate 12 is configured in the enrichment passage of the bypass duct 1 in cooperation with both ends of the enrichment passage and at a specific angle along the flue gas flow direction in the bypass duct 1. The filter membrane conveyor belt 120 fixed on one side of the breathable flat plate 12 intercepts particulates in the flue gas at the same angle. It can be understood that the enrichment passage is set in the bypass duct 1 to enrich particulates in the soot, and the breathable flat plate 12 and the filter membrane conveyor belt 120 are set in the bypass duct 1 to further enrich particulates. Therefore, when the soot content in the flue gas itself is relatively high, the structure shown in Figure 2B can be used for detection.

[0060] That is, referring to Figure 2B and Figure 3B, As can be seen from the above, at this time, the flue gas flow in the enrichment passage is relatively uniform, and the particulate matter distribution therein is also relatively uniform. Therefore, X-rays can be directly emitted from the detection source 30 to the detection area in the enrichment passage at a certain angle towards the enrichment passage to irradiate the particulate matter entrained by the flue gas, thereby achieving accurate detection. Under this implementation scheme, the X-ray emission field of the detection source 30, the X-ray reception field of the fluorescence detector 31, and the area between the upper gas path wall 130 and the lower gas path wall 140 of the enrichment passage together constitute the detection area. The particulate matter near the surface of the lens window 2, in the middle of the inner cavity of the enrichment passage, and near the inner wall far from the lens window 2 can all be effectively irradiated by the detection source 30 through the lens window 2.

[0061] In particular, when the length of the lens window 2 is between 20 - 35 cm, there is enough space for the detection source 30 and the fluorescence detector 31 to be arranged outside it and as close to its surface as possible, which enables the fluorescence detector 31 to make the most of receiving the characteristic X-ray fluorescence radiated by the particulate matter towards the lens window 2. Preferably, the length of the lens window 2 is 30 cm. At this length, the fluorescence detector 31 can effectively detect the characteristic X-rays emitted by the particulate matter in the flue gas with a concentration greater than a certain concentration threshold, and this concentration threshold is the above-mentioned 500 mg / m 3 .

[0062] Reference Figure 2A and Figure 3A , according to the monitoring device for inorganic elements in flue gas of the implementation scheme of the present application, another exemplary detection scheme is provided. When the soot concentration of the flue gas is lower than 500 mg / m 3 , it is difficult for the XRF detection equipment to detect the characteristic X-rays of the particulate matter flowing in the channel, and further increasing the length or width of the lens window 2 is also difficult to fundamentally improve this problem. Therefore, a breathable flat plate 12 is further provided to introduce a filter membrane. In the case of having the breathable flat plate 12, continuously increasing the breathable flat plate 12 may cause the particulate matter at both ends not to be irradiated by the detection module 3, so it is necessary to further increase the lens window 2, which increases the manufacturing cost. Therefore, it is preferred to set the length of the breathable flat plate 12 to 30 mm or slightly less than 30 mm to enable the X-ray beam from the other side of the lens window 2 to effectively irradiate the filter membrane; at this length, the particulate matter with a lower content will not accumulate on the filter membrane within a short detection time, avoiding the situation where some particulate matter cannot be irradiated.

[0063] At the preferred length, the breathable flat plate 12 can be arranged in a direction parallel to the flue gas flow and the lens window 2, and the two ends are respectively fixed to the upper wall 130 and the lower wall 140 of the gas path of the enrichment path. The detection area is a cylindrical area between the cross-sections where the upper and lower ends of the breathable flat plate 12 are located. After the flue gas enters the pipeline from the air inlet 10, it is blocked by the upper wall 130 of the gas path in the flow direction and enters the detection area from the left side, and then is blocked by the lower wall 140 of the gas path in the flow direction and leaves the detection area from the right side. During this process, the flue gas and the dust in it need to pass through the breathable flat plate 12 from the left side area of the detection area through the breathable flat plate 12 to the right side. The flow direction of the flue gas is perpendicular to the plane where the filter membrane conveyor belt 120 is located, so that the dust particles can be intercepted along the flow direction. In particular, the material of the filter membrane can be polytetrafluoroethylene (PTFE), preferably high-purity PTFE, such as industrial high-purity PTFE with a PTFE content of not less than 99.9%. It does not react with inorganic elements, and has an extremely small fiber diameter and a uniform pore size distribution, which is suitable for intercepting small-sized particles.

[0064] Specifically, in this embodiment, the monitoring device for inorganic elements in flue gas according to the embodiment of the present application can solve the problems of low particulate matter concentration and uneven interception. The upper wall 130 and the lower wall 140 of the gas path are respectively located on one side of the upper end and the opposite side of the lower end of the enrichment path, and there is partial overlap in the projection in the direction perpendicular to the flue gas flow direction, so as to facilitate fixing the breathable flat plate 12 in the overlapping area of the projection. The two ends of the breathable flat plate 12 are respectively fixed in the overlapping area of the projections of the upper wall 130 and the lower wall 140 of the gas path in the direction perpendicular to the flue gas flow direction, so as to be arranged parallel to the flowing flue gas.

[0065] In this way, under the partial blockage of the upper wall 130 of the gas path, the flue gas entering the detection area surges from the high-pressure area to the low-pressure area, that is, the area behind the upper wall 130 of the gas path. In this way, more flue gas will carry dust particles through the front end of the breathable flat plate 12 (i.e., the end fixed to the upper wall 130 of the gas path); when the flue gas flows to the lower wall 140 of the gas path, it accumulates and leaves from the low-pressure area on its right side. In this way, more flue gas will carry dust particles through the rear end of the breathable flat plate 12 (i.e., the end fixed to the lower wall 140 of the gas path); when the flue gas is in the detection area, it will also flow uniformly to the right to pass through the middle part of the breathable flat plate 12. In this way, there will be flue gas flows passing from one side to the other side along the direction of the filter membrane conveyor belt 120 on the breathable flat plate 12, so that the dust particles in it will fall uniformly on the filter membrane conveyor belt 120, rather than accumulating in the middle part or on both sides.

[0066] It can be understood that if only for the purpose of uniformly intercepting particulate matter, the breathable flat plate 12 can be directly orthogonally arranged in the enrichment path perpendicular to the flue gas flow direction. However, in this way, the detection module 3 cannot effectively irradiate the filter membrane conveyor belt 120 on the breathable flat plate 12 with X-rays, and there is a high probability that the characteristic X-rays of the particulate matter do not pass through the lens window 2, resulting in serious loss of optical signals. In addition, if the breathable flat plate 12 is arranged perpendicular to the enrichment path, its size will also be limited by the cross-sectional length or diameter of the enrichment channel along the direction perpendicular to the flue gas flow, which is not conducive to the uniform distribution of particulate matter and is prone to accumulation. Therefore, the breathable flat plate 12 is parallel to the inner wall of the enrichment channel, which not only increases the interception area but also facilitates the effective optical information exchange between the detection source 30 and the fluorescence detector 31 through the lens window 2 and the particulate matter.

[0067] In this way, the detection area can be used as both the collection area for particulate matter with different concentrations and the detection area for particulate matter. The detection process of the entire device is simple and has a high time resolution, and it can better meet the requirements for real-time and on-line monitoring of inorganic elements in flue gas compared with existing detection equipment.

[0068] In order to avoid non-uniform irradiation of particulate matter by the X-rays emitted by the detection source 30 and ensure the effective collection of characteristic X-rays, the monitoring device for inorganic elements in flue gas according to the implementation scheme of the present application provides a fixing method for the detection module 3 outside the lens window 2. The detection source 30 is used to emit a primary X-ray beam, and the fluorescence detector 31 is used to detect the characteristic X-rays of particulate matter. The detection source 30 and the fluorescence detector 31 can be a set of XRF ray fluorescence spectrometers. The lens window 2 is arranged on the wall of the enrichment path, and the detection module 3 measures the content of particulate matter on the filter membrane conveyor belt 120 through the lens window 2. The X-rays have strong penetration power for the lens window 2, and at the same time, it is necessary to avoid being absorbed by the lens window 2. Therefore, the material of the lens window 2 can be beryllium, and preferably high-purity beryllium. For example, an industrial-grade high-purity beryllium with a beryllium content of 99% is selected to manufacture the lens window 2. The X-rays have very strong penetration power for it and a very low absorption rate, which can ensure the smoothness and uniformity of the optical channel.

[0069] In particular, the element detection accuracy can be further optimized by setting the optimal sizes of multiple components of the bypass duct 1: As described above, in the preferred embodiment, the length of the lens window 2 in the flue gas flow direction is set to 30 mm, and the geometric center of the window is located at the middle position where the air flow in the enrichment path is relatively stable. Further, the detection source 30 can emit X-rays into the enrichment path or onto the air-permeable plate 12 inside the enrichment path at a certain emission angle (α) with respect to the lens window 2 to cover the particulate matter well, and a certain receiving angle (β) is set between the fluorescence detector 31 and the lens window 2 to effectively receive the characteristic X-rays generated by the elements at the primary X-ray irradiation location. Moreover, the geometric center of the air-permeable plate 12 is flush with the center of the lens window 2 in a direction perpendicular to the flue gas flow, ensuring that the particulate matter intercepted by the filter membrane conveyor belt 120 thereon can be effectively irradiated and emitted, especially the particulate matter at both ends.

[0070] In addition, the primary X-ray emission position of the detection source 30 is on one side of the lens window 2 close to the center, and the position of the fluorescence detector 31 is on the other side of the lens window 2 close to the center. The emission angle α between the primary X-ray emission position of the detection source 30 and the plane where the lens window 2 is located is preferably 50° - 65°, aiming to enable the primary X-ray beam of the detection source 30 to effectively irradiate the entire filter membrane conveyor belt 120, making the path length of the X-ray radiation on the uppermost layer of the particulate matter appropriate and improving the particulate matter sensitivity of the detection module 3.

[0071] It can be understood that when the angle between the primary X-ray emission angle α of the detection source 30 and the plane of the filter membrane on the filter membrane conveyor belt 120 is too small, one end of the filter membrane conveyor belt 120, that is, the upstream or downstream end position of the filter membrane in the flue gas flow, may not be irradiated; when the angle between the ray emission angle of the detection source 30 and the plane of the filter membrane on the filter membrane conveyor belt 120 is too large, there will be a problem of insufficient irradiation at at least one end of the filter membrane conveyor belt 120. To improve this problem, the detection source 30 can be moved to the center of the lens window 2, but the fluorescence detector 31 also has the same X-ray reception problem, which will cause a conflict in the spatial positions of the two devices, making at least one device unable to work well. Therefore, the detection source 30 and the fluorescence detector 31 need to be set at both ends of the lens window 2 according to their own working characteristics and avoid the above situation through the optimal angle.

[0072] Similarly, the receiving angle between the characteristic X-ray receiving position of the fluorescence detector 31 and the plane where the lens window 2 is located is preferably 40° - 55°, which can effectively receive the characteristic X-rays with random directions of the particulate matter. Refer to Figure 4, in order to balance the need for the detection source 30 and the fluorescence detector 31 to be close to the center of the surface of the lens window 2, so that when the two work together, the X-ray information exchange efficiency with the particulate matter reaches the optimum and the mutual interference is minimized, it is further preferably that the emission angle α of the detection source 30 is 60° and the reception angle β of the fluorescence detector 31 is 48°, as Figure 4 shown. In this way, the fluorescence detector 31 will not receive stray light, and the useful signal it detects is the characteristic X-ray fluorescence signal emitted by the particulate matter sample, rather than the primary X-ray beam emitted by the detection source 30, or the scattered light of the beam, etc.

[0073] In some embodiments, the detection source 30, the fluorescence detector 31 and the corresponding data analysis unit of the detection module 3 can all be existing products or experimental equipment. For example, the data analysis unit can be a multi-channel analyzer. The electrical signal obtained by the fluorescence detector 31 by converting the fluorescence photons of the characteristic X-rays is subjected to AD conversion in the data analysis unit, and the latter calculates the elemental composition in the particulate matter using the corresponding digital signal and sends it to an electronic device such as a computer to display the spectrum and analysis results. The entire detection process includes the emission of primary X-rays by the detection source 30, irradiating the particulate matter on the filter membrane conveyor belt 120 through the lens window 2; the fluorescence detector 31 receiving the characteristic X-rays released by the particulate matter on the filter membrane conveyor belt 120 through the lens window 2 to obtain the X-ray fluorescence energy spectrum of the particulate matter; the data analysis unit calculating the X-ray fluorescence intensity of the target inorganic element in the particulate matter based on the X-ray fluorescence energy spectrum and displaying the spectrum image and analysis results in the display device to obtain the content of the target inorganic element.

[0074] Exemplary method

[0075] Figure 5 illustrates a flowchart of an on-line monitoring method for inorganic elements in flue gas according to an embodiment of the present application.

[0076] As Figure 5 shown, the on-line monitoring method for inorganic elements in flue gas according to an embodiment of the present application includes the following steps.

[0077] Sampling step S110, using an air pump to extract the flue gas to be measured in the flue into the detection pipeline, enriching or intercepting the particulate matter sample containing the target inorganic element in the flue gas to be measured in the detection pipeline within a specified time, and the remaining flue gas returns to the flue through the detection pipeline and is discharged along with the flue; measuring step S120, emitting an X-ray beam to the obtained particulate matter sample through the measuring module, the particulate matter sample receives the irradiation of the X-ray beam and emits the characteristic X-ray fluorescence radiation of the target inorganic element, and the measuring module receives the characteristic X-ray fluorescence radiation of the target inorganic element and processes it to obtain the X-ray fluorescence energy spectrum.

[0078] And, calculation step S130, the calculation module processes the X-ray fluorescence energy spectrum by using a full-spectrum fitting method or a specific peak area integration method to obtain the characteristic X-ray fluorescence intensity of the target element in the particulate matter sample, and determines the content of the target element according to the relationship between the characteristic X-ray fluorescence intensity and the content; reset step S140, remove the particulate matter sample in the detection pipeline and reset the usage state of the measurement module. In this way, the content of the target inorganic element of the flue gas inorganic element in the flue can be obtained within a certain time range. By repeating the above collection step, measurement step, calculation step and reset step, the content of the target inorganic element of the flue gas to be measured in the flue can be continuously monitored, that is, on-line monitoring is realized.

[0079] It can be understood that according to the on-line monitoring method of the flue gas inorganic element in the embodiment of the present application, the enrichment path in the bypass pipeline 1 of the monitoring device for the inorganic element in the flue gas according to the embodiment of the present application can be used as the detection pipeline, and the particulate matter is intercepted and adsorbed by the filter membrane on the filter membrane conveyor belt 120 to obtain the particulate matter sample or the flowing particulate matter sample is directly enriched by using the enrichment path, the detection source 30 emits an X-ray beam to the particulate matter sample, and the fluorescence detector 31 receives the characteristic X-ray fluorescence radiation of the particulate matter sample through the lens window 2 to generate an X-ray fluorescence energy spectrum. Finally, the data analysis unit processes the X-ray fluorescence energy spectrum by using a full-spectrum fitting or a specific peak area integration method to obtain the characteristic X-ray fluorescence intensity of the target inorganic element in the particulate matter sample. In this way, the content of each target inorganic element can be obtained, and the content sizes of different target inorganic elements can also be intuitively compared.

[0080] In addition, the detection pipeline, the measurement module and / or the calculation module can also be any device, equipment or system commonly used by those skilled in the art. The appropriate detection pipeline, measurement module and / or calculation module can be selected according to the actual situation to realize the on-line monitoring of the target element in the flue gas, so as to meet the real-time monitoring and management of the flue gas emission status.

[0081] The monitoring device for inorganic elements in flue gas provided by this application is connected to the flue duct for ventilation at the upstream and downstream of the flue gas in the flue gas pipeline, serving as a bypass pipeline of the flue duct to allow the natural passage of flue gas; an enrichment path is set in the bypass pipeline to enrich the particulate matter in the soot, and the particulate matter can be further uniformly intercepted through the upper wall of the gas path and the lower wall of the gas path perpendicular to the bypass pipeline and the breathable flat plate parallel to the bypass pipeline. In cooperation with the lens window, the area where the particulate matter is enriched is used as the detection chamber, facilitating rapid detection through the ED-XRF-based detection module to obtain the concentration and type of inorganic elements contained in the particulate matter in the flue duct in real time. By adopting a bypass form, this application does not require additional sampling pipelines, greatly reducing pipeline losses and sampling time; through the design of the enrichment path and the breathable flat plate, a uniform enrichment effect of the soot is achieved; by setting the lens window and the detection module, non-contact and real-time measurement of the particulate matter is realized. On this basis, by optimizing the size, shape, and position of the bypass pipeline, the breathable flat plate, and / or the detection module, the detection accuracy is further improved to provide a reliable online flue gas inorganic element monitoring solution with high time resolution.

[0082] Embodiment

[0083] This application provides a general and / or specific description of the materials and test methods used in the experiment. For raw materials or instruments whose manufacturers are not specified, they are all conventional raw material products or instruments that can be obtained through commercial procurement.

[0084] The monitoring device for inorganic elements in flue gas is used to measure the mass concentration of inorganic elements in the flue gas particulate matter of an exhaust chimney of a smelter, and at the same time, a comparative test is carried out by using the standard method of manual sampling and a conventional XRF analysis instrument for sampling and detection. Among them, the ratio of the length of the bypass pipeline along the flue gas flow direction to the cross-sectional width along the direction perpendicular to the flue gas flow direction is set to 4:1. A breathable flat plate and a filter membrane conveyor belt thereon are set in the enrichment path, and the ratio of the length of the enrichment path along the flue gas flow direction to the cross-sectional width along the direction perpendicular to the flue gas flow direction is set to 5:3. The lengths of the lens window and the breathable flat plate are both set to 30 cm. The angles between the detection source and the fluorescence detector and the plane where the filter membrane on the filter membrane conveyor belt is located are set to 60° and 48° respectively. The filter membrane of the filter membrane conveyor belt is industrial-grade high-purity PTFE, and the lens window is made of industrial-grade high-purity beryllium. The same external environmental parameters are maintained during the entire monitoring process for the three comparative tests, that is, the same chimney is used for testing under the same temperature, humidity, and light conditions. Based on the manual analysis, the differences in the measured results and the analysis period between the monitoring device of this application and the conventional XRF analysis device during the monitoring process are compared to show the monitoring accuracy of the monitoring device of this application at high time resolution. Table 1 shows the monitoring results of arsenic and lead elements.

[0085] As can be seen from Table 1, the monitoring device for inorganic elements in the flue gas of this application can approach the true value of particulate matter in the flue gas of the pollution source to a greater extent, that is, the particulate matter concentration data obtained by the standard manual sampling method. In addition, the monitoring device for inorganic elements in the air produces results at the fastest speed, and its average analysis cycle in the entire monitoring process is <1 min. The measured results are also very close to the standard results measured by the manual standard method compared with the conventional XRF analysis. Specifically, for the monitoring of two common elements, arsenic and lead, the data measured by the monitoring device for inorganic elements in the flue gas in a short time is closer to the manual standard method, while the average detection deviation between the conventional XRF analysis and the manual standard method within the same time is >20%, resulting in obvious data distortion.

[0086] Table 1 Comparison of the detection results of the monitoring device of this application, manual sampling, and conventional XRF device

[0087]

[0088] Therefore, it can be seen that for the monitoring device of inorganic elements in the flue gas according to the embodiments of this application, compared with the conventional XRF analysis device, the monitoring time resolution of the specified target elements is significantly improved, and at the same time, it can maintain good analysis accuracy within a relatively short detection time.

[0089] The basic principles of this application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, advantages, effects, etc. mentioned in this application are only examples and not limitations. It cannot be considered that these advantages, advantages, effects, etc. are essential for each embodiment of this application. In addition, the above-disclosed specific details are only for the purpose of illustration and easy understanding, rather than limitations. The above details do not limit this application to necessarily adopt the above specific details to implement.

[0090] Words such as "including", "comprising", "having", etc. in this application are open-ended words, meaning "including but not limited to", and can be used interchangeably with each other. The words "or" and "and" used here refer to the word "and / or", and can be used interchangeably with each other, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with each other.

[0091] It should also be noted that in the methods, systems, and devices of this application, each step or each module can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of this application.

[0092] The above description has been given for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions, and sub-combinations thereof.

Claims

1. Online monitoring device for inorganic elements in flue gas, including: Bypass piping and detection modules; The bypass pipeline has an air inlet, an air outlet and an enrichment passage, the air inlet and the air outlet are respectively arranged at the upstream and downstream of the flue, the bypass pipeline is connected with the flue gas through the air inlet and the air outlet, and an air pump is arranged at the air inlet; The enrichment passage is at least a part of the bypass pipe, and the cross-sectional area of ​​the enrichment passage along the direction perpendicular to the flow of the smoke is smaller than the cross-sectional area of ​​the bypass pipe along the direction perpendicular to the flow of the smoke, so that the gas path of the smoke in the enrichment passage becomes narrower and the flow rate is accelerated; The enrichment passage is in the shape of a dumbbell groove.

2. The on-line monitoring device for inorganic elements in flue gas according to claim 1, wherein: The bypass pipeline also includes: a breathable flat plate and a filter membrane conveyor belt; The air-permeable flat plate is arranged in the enrichment passage at a certain angle to the flow direction of the smoke in the enrichment passage, and is used to fix the filter membrane conveyor belt; The filter membrane conveyor belt is used to intercept particulate matter samples in the smoke, and the two ends of the filter membrane conveyor belt are rollers or reels used to transport the filter membrane on the filter membrane conveyor belt into or out of the detection area; The material of the filter membrane is PTFE; Preferably, the ratio of the length of the bypass pipe along the flue gas flow direction to the cross-sectional width or diameter of the bypass pipe perpendicular to the flue gas flow direction is in the range of 6:1 to 3:1; Preferably, the ratio of the length of the enrichment passage along the flue gas flow direction to the cross-sectional width or diameter of the enrichment passage perpendicular to the flue gas flow direction is in the range of 2:1 to 5:

3.

3. The on-line monitoring device for inorganic elements in flue gas according to claim 2, wherein: The enrichment passage has an upper wall at the upper end and a lower wall at the lower end, and the projections of the upper wall and the lower wall perpendicular to the direction of smoke flow in the enrichment passage overlap to change the flow direction of smoke in the enrichment passage.

4. The on-line monitoring device for inorganic elements in flue gas according to claim 3, The gas passage upper wall and the gas passage lower wall are respectively located on one side of the upper end and the other side of the lower end of the enrichment passage, and their projections perpendicular to the flue gas flow direction in the enrichment passage partially overlap.

5. The on-line monitoring device for inorganic elements in flue gas according to claim 3, wherein: The air-permeable plate is arranged in the enrichment passage parallel to the flue gas flow direction; The projection of the air-permeable flat plate in a direction perpendicular to the flow direction of the smoke in the enrichment passage is located in an overlapping area of ​​the projections of the upper wall of the gas passage and the lower wall of the gas passage in a direction perpendicular to the flow direction of the smoke in the enrichment passage.

6. The on-line monitoring device for inorganic elements in flue gas according to claim 1, wherein: The bypass conduit also includes a lens window; The lens window is arranged on the wall of the bypass pipe, and the detection module measures the element content of the particulate matter in the enrichment passage through the lens window; The lens window is made of beryllium.

7. The on-line monitoring device for inorganic elements in flue gas according to claim 6, wherein: The detection module includes a detection source, a fluorescence detector and a data analysis unit; The detection source emits primary X-rays to irradiate the particle sample in the flue gas through the lens window; The fluorescence detector receives characteristic X-rays released by the particle sample in the smoke through the lens window to obtain the X-ray fluorescence spectrum of the particle; The data analysis unit calculates the X-ray fluorescence intensity of the target element in the particulate matter based on the X-ray fluorescence spectrum to obtain the target element content.

8. The on-line monitoring device for inorganic elements in flue gas according to claim 7, wherein: The length of the lens window along the direction of smoke flow ranges from 20 cm to 35 cm; The angle between the primary X-ray emission position of the detection source and the plane where the filter membrane is located is in the range of 50° to 65°; The angle between the characteristic X-ray receiving position of the fluorescence detector and the plane where the filter membrane is located is in the range of 40° to 55°.

9. The on-line monitoring device for inorganic elements in flue gas according to claim 1, wherein: The air inlet and the air outlet are connected to the flue wall via flanges.

10. An online monitoring method for inorganic elements in flue gas, comprising: The collection step is to use an air pump to extract the smoke to be tested in the flue into the detection pipeline, and to use the detection pipeline to enrich or intercept the particle sample containing the target inorganic element in the smoke to be tested within a specified time, and the remaining smoke flows back to the flue through the detection pipeline and is discharged with the flue; A measuring step, emitting an X-ray beam to the obtained particulate matter sample through a measuring module, the particulate matter sample receives the X-ray beam and emits characteristic X-ray fluorescence radiation of the target inorganic element, the measuring module receives the characteristic X-ray fluorescence radiation of the target inorganic element, and processes it to obtain an X-ray fluorescence spectrum; Calculation step: the calculation module processes the X-ray fluorescence spectrum using a full spectrum fitting method or a specific peak area integration method to obtain the characteristic X-ray fluorescence intensity of the target inorganic element in the particulate matter sample, and determines the concentration of the target inorganic element based on the relationship between the characteristic X-ray fluorescence intensity and the element content; A reset step, removing the particle sample in the detection pipeline and resetting the working state of the measurement module; The collecting step, the measuring step, the calculating step and the resetting step are repeated to continuously monitor online the concentration of the target inorganic element in the flue gas to be tested in the flue.

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