Measuring system, measuring equipment and measuring method for dust concentration

Abstract

The embodiment of the invention provides a dust concentration measuring system, measuring equipment and a measuring method, and belongs to the field of environmental protection detection. Comprising a sampling pipe and a sample return pipe which are located in a flue, the sampling pipe collects gas from the flue, and the gas is discharged through the sample return pipe; the drying device and the gas detection device are located outside the flue; and the gas collected from the flue by the sampling pipe sequentially passes through the drying device and the gas detection device through the connecting pipeline and then is discharged from the sample return pipe. According to the invention, gas can be directly dried by adopting multi-stage filtration, so that the influence of water vapor on an optical instrument is reduced. Aiming at error accumulation caused by multiple equipment detection steps such as dilution and shunting in the prior art, the detection precision is higher, and the influence of excessive drying links on the detection precision of the dust concentration in the gas can be avoided on the premise of ensuring the drying of the gas. In addition, the structure is simple, the control route is simple, and operation is more convenient.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection detection, and in particular to a dust concentration measurement system, a measurement device and a measurement method. Background Art

[0002] At present, waste gas emissions from factories are usually discharged into the atmosphere through pipes and chimneys. These waste gas emissions are collectively called flues. The waste gas discharged from factories contains many components, including dust particles.

[0003] In order to measure the dust particles in the exhaust gas, it is generally achieved through an online measuring device installed on the chimney, but this online measuring device can only be used in a dry and high-concentration environment. At present, many exhaust gases must be washed before being discharged, and the emission concentration is low. In this way, the exhaust gas is high-humidity and low-concentration exhaust gas. Some liquid water vapor in the exhaust gas will be mistaken for dust and make the measurement result inaccurate.

[0004] In order to solve this problem, the prior art discloses an online measurement system for flue dust concentration including a sampling tube and a shunt joint, wherein a dilution chamber and a diversion chamber are provided on the shunt joint, and the absolute water content in the sampled gas is reduced by diverting, diluting, heating and other steps. However, this structure is relatively complicated. On the one hand, the detection of multiple devices will cause the accumulation of errors, resulting in a decrease in detection accuracy; on the other hand, it cannot guarantee real-time detection of dust at the current flow rate. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a dust concentration measurement system, a measurement device and a measurement method, so as to overcome the above-mentioned defects.

[0006] In order to achieve the above-mentioned purpose, an embodiment of the present invention provides a dust concentration measurement system, wherein the measurement system comprises: a sampling tube and a return sample tube located in the flue, wherein the sampling tube collects gas from the flue and discharges the gas through the return sample tube; a drying device and a gas detection device located outside the flue, wherein the drying device comprises a first steam-water separator, a drying tube and a second steam-water separator; and a connecting pipeline, one end of which is connected to the sampling tube and the other end of which is connected to the return sample tube, wherein the gas collected from the flue by the sampling tube through the connecting pipeline passes through the drying device and the gas detection device in sequence and is discharged from the return sample tube.

[0007] Optionally, the sampling tube is an arc-shaped elbow with an air inlet facing downward, and the sampling tube and the return sampling tube are fixed to each other.

[0008] Optionally, the gas detection device includes: a light emitting unit, emitting light to the gas; a light receiving unit, receiving the light; and a spectral analysis unit, electrically connected to the light receiving unit via an optical fiber, for analyzing the light received by the light receiving unit to detect dust concentration in the gas.

[0009] Optionally, the connecting pipeline is a heating pipe, and the measuring system also includes: a cleaning pipeline, including an air intake pipeline and an exhaust pipeline, one end of the air intake pipeline is connected to a first solenoid valve for controlling whether compressed air is introduced, and the other end is connected to the sampling tube; one end of the exhaust pipeline is connected to the sampling tube, and the other end is connected to a second solenoid valve for controlling the discharge of the compressed air; wherein the cleaning pipeline also includes a first distribution pipeline, located between the first solenoid valve and the sampling tube, and a third solenoid valve is arranged on the first distribution pipeline for controlling the flow rate of the compressed air to the sampling tube.

[0010] Optionally, the cleaning pipeline also includes: a second distribution pipeline, located between the first solenoid valve and the first lens of the light emitting unit, a fourth solenoid valve is arranged on the second distribution pipeline for controlling the flow rate of the compressed air to the first lens; and a third distribution pipeline, located between the first solenoid valve and the second lens of the light receiving unit, a fifth solenoid valve is arranged on the third distribution pipeline for controlling the flow rate of the compressed air to the second lens; Optionally, the measurement system also includes: a heat preservation device, accommodating the drying device and the gas detection device; and a heater, heating the heat preservation device to maintain the temperature in the heat preservation device equal to the gas temperature at the sampling tube.

[0011] Optionally, the measurement system further includes: a flow control device, including a pump, a second flow meter and a flow valve, for controlling the gas flow rate of the gas in the measurement system.

[0012] Optionally, the measurement system further comprises: a first flow meter for detecting the gas flow rate in the flue, wherein the flow control device is used to keep the gas flow rate in the measurement system equal to the gas flow rate in the flue.

[0013] In another aspect, the present invention provides a dust concentration measuring device, the measuring device comprising a cabinet, in which the dust concentration measuring system described above is installed.

[0014] On the other hand, the present invention provides a method for measuring dust concentration, which comprises: collecting gas from the flue through a sampling tube located in the flue; drying the gas through a drying device, wherein the drying device comprises a first steam-water separator, a drying tube and a second steam-water separator; detecting the dust concentration of the gas through a gas detection device, wherein the drying device and the gas detection device are located outside the flue; and discharging the gas through a return sampling tube located in the flue.

[0015] Through the above technical solution, the beneficial effects of the present invention are:

[0016] The present invention can directly dry the gas by multi-stage filtration, thereby reducing the influence of water vapor on optical instruments. In view of the error accumulation caused by multiple equipment detection steps such as dilution and diversion in the prior art, the present invention has higher detection accuracy and can avoid excessive drying steps affecting the detection accuracy of dust concentration in the gas while ensuring the dryness of the gas.

[0017] In addition, the present invention has a simple structure and a simple control route, which makes the operation more convenient, and the product has an integrated design, so the overall volume is smaller.

[0018] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0020] Figure 1 It is a schematic diagram of the structure of a dust concentration measurement system provided by an embodiment of the present invention;

[0021] Figure 2 It is a flow chart of a dust concentration measurement method provided by an embodiment of the present invention.

[0022] Description of Reference Numerals

[0023] 100 measurement systems;

[0024] 1 flue; 2 sampling tube; 3 return sample tube;

[0025] 41 a first steam-water separator; 42 a drying tube; 43 a second steam-water separator;

[0026] 5 gas detection device; 51 light emitting unit; 52 optical fiber; 53 spectrum analysis unit;

[0027] 61 pump; 62 second flow meter; 63 flow valve;

[0028] 7. Insulation device;

[0029] A the first solenoid valve; B the second solenoid valve; C the third solenoid valve; D the fourth solenoid valve; E the fifth solenoid valve. DETAILED DESCRIPTION

[0030] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0031] The present invention first provides a dust concentration measurement system 100, such as Figure 1 As shown, the measurement system 100 may include: a sampling tube 2, a sample return tube 3, a drying device, a gas detection device 5 and a connecting pipeline.

[0032] Among them, one end of the connecting pipeline is connected to the sampling tube 2, and the other end is connected to the return sample tube 3. The gas collected from the flue 1 by the sampling tube 2 can be discharged from the return sample tube 3 after passing through the drying device and the gas detection device 5 in sequence through the connecting pipeline.

[0033] Among them, the sampling tube 2 and the return sample tube 3 can be located in the flue 1 and fixed to each other. The sampling tube 2 collects gas from the flue 1 and discharges the gas through the return sample tube 3. That is, the return sample tube 3 is the outlet end of the sampled gas, which can make the gas form a return injection mode to avoid discharging the test gas to the outside to cause air pollution. In one embodiment, the sampling tube 2 is an arc-shaped elbow with the air inlet facing downward, and such a setting can increase the air intake.

[0034] The drying device and the gas detection device 5 may be located outside the flue 1. The drying device may include a first steam-water separator 41, a drying tube 42, and a second steam-water separator 43. Such an arrangement allows the gas entering from the sampling tube 2 to first pass through the steam-water separator 41 to separate the wet flue gas in the gas from the water; then pass through the drying tube 42 to dry the water; and finally, the steam-water separator 43 performs a secondary separation on the water in the gas, thereby obtaining fully dried flue gas and reaching the sample gas chamber in the gas detection device 5.

[0035] In one embodiment, the drying tube 42 can be a heating tube, and by arranging a steam-water separator 41 in front of it, it can effectively prevent excessive water vapor from flowing through the drying tube, resulting in insufficient drying capacity. And by arranging a steam-water separator 43 behind it, even if the gas is not fully dried, secondary steam-water separation can be performed, thereby effectively ensuring the drying effect of the flue gas.

[0036] In one embodiment, the connecting pipeline can be a heat tracing pipe. The heat tracing pipe is an efficient and practical industrial equipment, which is widely used in various industrial fields. The heat tracing pipe can transfer heat in a variety of ways, including heat convection, heat radiation and heat conduction, to supplement the heat loss of the material in the main pipeline or equipment, and resist the cooling effect of the external environment. Thus, by means of constant temperature or heating, the crystallization and solidification of the material can be effectively prevented, the process requirements can be met, and the production efficiency and product quality can be ensured.

[0037] The working principle of the heat tracing pipe system is to arrange the heat tracing pipe and the process pipe closely and wrap them together in an insulation sleeve. The heat tracing medium is passed into the heat tracing pipe, and the heat generated by this medium is transferred to the process pipe in a variety of ways, thereby heating the process medium therein. This design not only helps to maintain the temperature of the material, but also resists the cooling effect of the external environment through the insulation layer to ensure production efficiency and product quality. Specific to the application scenario, for example, the CEMS heat tracing pipe is an important component in the environmental monitoring system, which is used for online analysis systems, sample gas pretreatment systems, etc. The material of the heat tracing pipe can include, for example, No. 20 steel, stainless steel pipe, etc., so as to avoid the corrosion of the heated material on the heat tracing pipe. In another embodiment, the heat tracing pipe can be composed of a corrosion-resistant high-performance fluororesin conduit, a special self-limiting temperature electric heating tape and various wires, plus a glass fiber insulation layer and an extruded polyethylene or polyvinyl chloride protective jacket to ensure stable operation in harsh environments. In addition, its specifications can also be selected according to different industrial application requirements, which will not be repeated here.

[0038] By setting a heating pipe, in combination with the first steam-water separator 41, the drying pipe 42 and the second steam-water separator 43 in the drying device, the present invention can use multi-stage filtration to directly dry the gas, thereby reducing the impact of water vapor on optical instruments. Compared with the dilution and diversion steps in the prior art, it can avoid excessive drying steps affecting the detection accuracy of dust concentration in the gas while ensuring the dryness of the gas.

[0039] In one embodiment, the gas detection device 5 may include: a light emitting unit 51, such as an ultraviolet light emitting unit, for emitting light to the gas; a light receiving unit, for receiving light; and a spectral analysis unit 53, for being electrically connected to the light receiving unit through an optical fiber 52, and then analyzing the light received by the light receiving unit to detect the dust concentration in the gas.

[0040] In one embodiment, in order to clean the sampling tube 2, the measurement system 100 may further include: a cleaning pipeline, which may include an air intake pipeline and an air exhaust pipeline. One end of the air intake pipeline is connected to the first solenoid valve A, which is used to control whether compressed air is introduced, and the other end is connected to the sampling tube 2; one end of the air exhaust pipeline is connected to the sampling tube 2, and the other end is connected to the second solenoid valve B, which is used to control the discharge of compressed air.

[0041] In one embodiment, the cleaning pipeline may further include a first distribution pipeline, which is located between the first solenoid valve A and the sampling tube 2. A third solenoid valve C may be provided on the first distribution pipeline to control the flow rate of compressed air to the sampling tube 2. That is to say, the cleaning pipeline mainly introduces compressed air from the first solenoid valve A, controls the intake flow rate through the third solenoid valve C, and discharges it from the second solenoid valve B after high-pressure air cleaning of the sampling tube 2. In one embodiment, in order to clean the lenses at both ends of the sample gas chamber of the gas detection device 5, the cleaning pipeline may further include: a second distribution pipeline and a third distribution pipeline. The second distribution pipeline is located between the first solenoid valve A and the first lens of the light emitting unit 51, and a fourth solenoid valve D may be provided on the second distribution pipeline to control the flow rate of compressed air to the first lens. The third distribution pipeline is located between the first solenoid valve A and the second lens of the light receiving unit, and a fifth solenoid valve E may be provided on the third distribution pipeline to control the flow rate of compressed air to the second lens. The cleaning principle is: the compressed air is introduced from the first solenoid valve A, and the air intake flow is controlled by the fourth solenoid valve D and the fifth solenoid valve E respectively, and the lenses at both ends of the sample gas chamber are cleaned by high-pressure air, and then flow through the gas path and are discharged from the second solenoid valve B. Such a front and rear cleaning structure of the gas path pipeline can effectively ensure the cleanliness of the gas path and improve the detection accuracy; at the same time, it can optimize the gas path system, and the product is replaced in an integrated manner, which is smaller in size.

[0042] In one embodiment, the measurement system 100 may further include: an insulation device 7 for accommodating a drying device and a gas detection device 5. In addition, a heater may be provided in the insulation device 7 for heating the insulation device 7. For example, a first temperature of the gas at the sampling tube 2 may be detected by a first thermometer, and a second temperature in the insulation device 7 may be detected by a second thermometer. When the second temperature is lower than the first temperature, the heater is turned on by a controller to heat the insulation device 7; when the second temperature is higher than the first temperature, the heater is turned off by a controller, and the insulation device 7 is cooled naturally. Through the above-mentioned device and control method, it is possible to maintain the temperature in the insulation device 7 equal to the gas temperature at the sampling tube 2, so that the test gas is consistent with the temperature in the flue gas tower, thereby preventing the temperature difference from affecting the detection accuracy.

[0043] In one embodiment, the measurement system 100 may further include: a flow control device, which may include a pump 61 , a second flow meter 62 and a flow valve 63 , for controlling the gas flow rate of the gas in the measurement system 100 .

[0044] In addition, a first flow meter may be provided in the flow control device for detecting the gas flow rate in the flue 1, so that the gas flow rate in the measurement system 100 can be controlled, for example, it can be kept equal to the gas flow rate in the flue 1 to achieve isokinetic sampling of the gas. For example, the first gas flow rate in the flue 1 can be detected by the first flow meter on the chimney, and the second gas flow rate in the measurement system 100 can be detected by the second flow meter, and the opening of the pump can be adjusted to meet the flow rate of the monitored device equal to the flue gas flow rate. When the second gas flow rate is less than the first gas flow rate, the controller is used to increase the power of the pump 61 and increase the opening of the flow valve 63 to increase the second gas flow rate in the measurement system 100; when the second gas flow rate is greater than the first gas flow rate, the controller is used to reduce the power of the pump 61 and reduce the opening of the flow valve 63 to reduce the second gas flow rate in the measurement system 100. Through the above device and control method, it is possible to maintain the gas flow rate in the measurement system 100 equal to the gas flow rate in the flue 1.

[0045] Therefore, the present invention adopts a real-time sampling method to effectively ensure the concentration of flue gas particles at the current flue gas flow rate. Compared with the existing technology that adopts dilution and diversion solutions, it can well ensure the detection of dust at the current flow rate, and at the same time ensure the real-time synchronization of the flue gas flow rate with the flue gas outlet flow rate in the monitor. In addition, the present invention has a simple structure and a simple control route, making the operation more convenient. Compared with competing products that use multiple pumps, flow meters and branch routes to meet the gas samples that need to be monitored, the detection of multiple devices will cause errors to accumulate, so the detection accuracy of the present invention is higher.

[0046] On the other hand, the present invention also discloses a dust concentration measuring device, which may include a cabinet, in which the dust concentration measuring system 100 described above is installed. Since the measuring device includes the above-mentioned measuring system 100, it naturally has all the above-mentioned functions and beneficial effects.

[0047] On the other hand, the present invention also discloses a method 200 for measuring dust concentration, such as Figure 2 As shown, the measurement method 200 may include:

[0048] Step S210, collecting gas from the flue through a sampling tube located in the flue;

[0049] Step S220, drying the gas by a drying device, wherein the drying device may include a first steam-water separator, a drying tube, and a second steam-water separator;

[0050] Step S230, detecting dust concentration of the gas by a gas detection device, wherein the drying device and the gas detection device are located outside the flue; and

[0051] Step S240, exhausting the gas through a sample return pipe located in the flue.

[0052] In one embodiment, the sampling tube is an arc-shaped elbow with an air inlet facing downward, and the sampling tube and the sample return tube are fixed to each other.

[0053] In one embodiment, the gas detection device includes: a light emitting unit that emits light to the gas; a light receiving unit that receives the light; and a spectral analysis unit that is electrically connected to the light receiving unit via an optical fiber and analyzes the light received by the light receiving unit to detect the dust concentration in the gas.

[0054] In one embodiment, the connecting pipeline is a heat tracing pipe, and the measuring method further includes: cleaning the sampling pipe through a cleaning pipeline. The cleaning pipeline includes an air intake pipeline and an exhaust pipeline, one end of the air intake pipeline is connected to a first solenoid valve for controlling whether compressed air is introduced, and the other end is connected to the sampling pipe; one end of the exhaust pipeline is connected to the sampling pipe, and the other end is connected to a second solenoid valve for controlling the discharge of compressed air; the cleaning pipeline also includes a first distribution pipeline, which is located between the first solenoid valve and the sampling pipe, and a third solenoid valve is arranged on the first distribution pipeline for controlling the flow of compressed air to the sampling pipe.

[0055] In one embodiment, the cleaning pipeline further includes: a second distribution pipeline, located between the first solenoid valve and the first lens of the light emitting unit, a fourth solenoid valve is arranged on the second distribution pipeline, and is used to control the flow rate of compressed air to the first lens; and a third distribution pipeline, located between the first solenoid valve and the second lens of the light receiving unit, a fifth solenoid valve is arranged on the third distribution pipeline, and is used to control the flow rate of compressed air to the second lens;

[0056] In one embodiment, the measuring method further comprises: maintaining the temperature in the gas detection device equal to the gas temperature at the sampling tube by accommodating a heat preservation device in the drying device and the gas detection device. For example, the heat preservation device may be heated by a heater to maintain the temperature in the heat preservation device equal to the gas temperature at the sampling tube.

[0057] In one embodiment, the measuring method further comprises: controlling the gas flow rate of the gas in the measuring system by a flow control device. For example, the flow control device may include a pump, a second flow meter and a flow valve. In addition, the flow control device may further include: a first flow meter for detecting the gas flow rate in the flue, so as to keep the gas flow rate in the measuring system equal to the gas flow rate in the flue.

[0058] The present invention can directly dry the gas by multi-stage filtration, thereby reducing the influence of water vapor on optical instruments. In view of the error accumulation caused by multiple equipment detection steps such as dilution and diversion in the prior art, the present invention has higher detection accuracy and can avoid excessive drying steps affecting the detection accuracy of dust concentration in the gas while ensuring the dryness of the gas.

[0059] In addition, the present invention has a simple structure and a simple control route, which makes the operation more convenient, and the product has an integrated design, so the overall volume is smaller.

[0060] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0061] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A dust concentration measurement system, characterized in that: The measurement system comprises: A sampling tube and a return sample tube located in the flue, wherein the sampling tube collects gas from the flue and discharges the gas through the return sample tube; a drying device and a gas detection device located outside the flue, wherein the drying device comprises a first steam-water separator, a drying tube and a second steam-water separator; and A connecting pipeline has one end connected to the sampling tube and the other end connected to the return sample tube, wherein the gas collected from the flue by the sampling tube through the connecting pipeline passes through the drying device and the gas detection device in sequence and is discharged from the return sample tube.

2. The measuring system according to claim 1, characterized in that The sampling tube is an arc-shaped elbow with an air inlet facing downward, and the sampling tube and the return sampling tube are fixed to each other.

3. The measuring system according to claim 1, characterized in that The gas detection device comprises: a light emitting unit for emitting light toward the gas; a light receiving unit, receiving the light; and The spectrum analysis unit is electrically connected to the light receiving unit through an optical fiber, and analyzes the light received by the light receiving unit to detect the dust concentration in the gas.

4. The measuring system according to claim 1, characterized in that The connecting pipeline is a heat tracing pipe, and the measuring system further comprises: a cleaning pipeline, including an air intake pipeline and an exhaust pipeline, One end of the air intake pipeline is connected to the first solenoid valve for controlling whether compressed air is introduced, and the other end is connected to the sampling tube; One end of the exhaust pipeline is connected to the sampling tube, and the other end is connected to the second solenoid valve for controlling the exhaust of the compressed air; The cleaning pipeline further includes a first distribution pipeline located between the first solenoid valve and the sampling tube. A third solenoid valve is arranged on the first distribution pipeline to control the flow of the compressed air to the sampling tube.

5. The measuring system according to claim 4, characterized in that The cleaning pipeline also includes: a second distribution pipeline, located between the first solenoid valve and the first lens of the light emitting unit, a fourth solenoid valve is provided on the second distribution pipeline for controlling the flow of the compressed air to the first lens; and The third distribution pipeline is located between the first solenoid valve and the second lens of the light receiving unit. A fifth solenoid valve is arranged on the third distribution pipeline to control the flow of the compressed air to the second lens.

6. The measuring system according to claim 1, characterized in that The measuring system further comprises: a heat preservation device, accommodating the drying device and the gas detection device; and A heater heats the heat preservation device to maintain the temperature in the heat preservation device equal to the gas temperature at the sampling tube.

7. The measuring system according to claim 1, characterized in that The measuring system further comprises: The flow control device comprises a pump, a second flow meter and a flow valve, and is used to control the gas flow rate of the gas in the measurement system.

8. The measuring system according to claim 7, characterized in that The measuring system further comprises: a first flow meter for detecting the gas flow rate in the flue, The flow control device is also used to keep the gas flow rate in the measurement system equal to the gas flow rate in the flue.

9. A dust concentration measuring device, characterized in that: The measuring device comprises a cabinet, in which a dust concentration measuring system according to any one of claims 1 to 8 is installed.

10. A method for measuring dust concentration, characterized in that: The measuring method comprises: collecting gas from the flue through a sampling pipe located in the flue; Drying the gas by a drying device, wherein the drying device comprises a first steam-water separator, a drying tube and a second steam-water separator; Performing dust concentration detection on the gas by means of a gas detection device, wherein the drying device and the gas detection device are located outside the flue; and The gas is discharged through a return pipe located in the flue.

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