Condensable particulate matter on-line monitoring device based on industrial smoke plume simulation

Abstract

The utility model belongs to the technical field of environment monitoring, and particularly relates to an online condensable particulate matter monitoring device based on industrial smoke plume simulation. The device comprises a particulate matter grading device, a pipeline heating device, a sheath gas distribution device, two throttling valves, a straight condensation pipe, two particulate matter filtering devices, a gas cooling device, a diluent gas distribution device, a dilution cavity, a particulate matter sensor and a sucking pump. The two-stage condensation and dilution technology with sheath gas protection is adopted, efficient condensation and drying of condensable particles are achieved, and measurement deviation caused by gas absorption and wall surface loss is avoided. And online measurement of the concentration of the captured particulate matters is realized through the particulate matter sensor, and online monitoring of the condensable particulate matters is realized. The device can effectively solve the problem of online real-time monitoring in the prior art, reduce gas absorption deviation and dilution wall surface loss, improve the precision and reliability of monitoring the condensable particulate matters of the stationary source, shorten the single measurement time and improve the time resolution.

Description

Technical Field

[0001] The utility model belongs to the technical field of environmental monitoring, and particularly relates to an on-line monitoring device for condensable particulate matter from stationary sources. Background Technique

[0002] Condensable Particulate Matter (CPM) exists in a gaseous state during flue gas emission, but will quickly condense into liquid or solid particulate matter after leaving the flue. Since CPM cannot be trapped by a filter membrane or filter cartridge in the flue, the existing particulate matter monitoring methods cannot effectively detect CPM. However, the formation and existence of CPM have important impacts on the atmospheric environment and human health. Therefore, it is particularly important to accurately monitor and control CPM.

[0003] The currently widely adopted sampling method for condensable particulate matter (CPM) from stationary sources is Method 202 recommended by the US Environmental Protection Agency (US EPA). First, particulate matter with a diameter greater than 2.5 μm is removed by a cyclone sampler. Then, according to the requirements of EPAMethod201A, isokinetic sampling is used to collect PM2.5 on a 47-mm heated filter membrane. To prevent the condensation of hot flue gas, the sampling inlet pipeline is heated to 10 °C higher than the flue gas temperature. Subsequently, the sampled flue gas enters the CPM condensation section. This section includes a vertical condenser, two dry impingers, a CPM filter membrane holder, an impinger filled with water, and an impinger filled with silica gel, arranged in sequence. To ensure that the flue gas temperature at the end of the CPM filter membrane holder remains below 30 °C, these impingers are placed in a water bath. During the measurement process, the condensation components are cooled and condensed in the dry impingers, and the uncondensed components are further collected on a 90-mm CPM filter membrane. The sampling time is 90 to 120 minutes, and the flow rate is 9 to 10 L / min. During this process, water vapor also condenses in the vertical condenser and dry impingers, and the condensed water may absorb soluble substances (such as SO2 and NO2) that do not belong to CPM, resulting in a positive deviation in the CPM emission result.

[0004] Although high-purity nitrogen is immediately purged at a flow rate of 14.5 L / min for 60 minutes after each sampling to remove the positive deviation of CPM caused by the dissolution of SO2 in the dry impinger, the positive deviation caused by the dissolution of SO2 cannot be completely eliminated.

[0005] The International Organization for Standardization (ISO) has issued a standard sampling method for measuring PM2.5 in flue gas (ISO 25597:2013). This method uses a dilution sampling system, which includes a sampling inlet, an air compressor, a dilution chamber, and a total PM2.5 collection section. Before sampling, a preheated cyclone sampler needs to be inserted into the flue to remove particulate matter larger than 2.5 μm. At the same time, the sampling inlet pipeline is heated to 10 °C higher than the flue gas temperature. The dilution air provided by the air compressor is purified through silica gel, activated carbon, and high-efficiency filters to remove moisture, organic compounds, and particulate matter. The high-temperature flue gas is mixed with the dilution air at a ratio of 10:1 to 20:1 to simulate the rapid dilution and condensation process of flue gas emissions into the atmosphere. The mixture stays in the residence chamber for about 10 seconds, and its temperature and relative humidity are controlled at below 42 °C and 70% respectively. In the residence chamber, the condensable gas precursors are converted into particulate matter through heterogeneous and homogeneous condensation. Since there is no water vapor condensation during the measurement process, soluble precursors (such as SO2 and NO2) will not be absorbed by liquid water. Finally, the total PM2.5 (including FPM2.5 and CPM) is collected on a 47 mm filter at a flow rate of 16.7 L / min for 2 to 3 hours. At the same time, the conventional in-flue PM sampling is carried out through a two-stage virtual impactor at a flow rate of 30 L / min for 60 minutes. By comparing the concentrations of total PM2.5 and FPM2.5, the CPM concentration of fixed-source emissions can be calculated.

[0006] Although the dilution condensation method avoids the absorption interference of gaseous substances, this method has deficiencies. Due to the relatively large inner wall area of the dilution condensation system, the CPM cannot be completely recovered after sampling, resulting in wall losses and weighing errors, so that the CPM concentration in the dilution chamber is lower than the actual flue gas concentration.

[0007] According to the currently developed patented technologies, the devices and methods for sampling and monitoring condensable particulate matter from fixed sources using the controlled condensation or dilution method still have the following problems:

[0008] Difficulty in online real-time monitoring: Most existing devices rely on manual operation, and the collected samples need to be further analyzed in the laboratory. Some devices that achieve online automatic monitoring have not effectively solved the deficiencies of the condensation and dilution methods, resulting in measurement deviations.

[0009] Low condensation efficiency: Although many related patents mention condensation or dilution, they do not effectively control parameters such as the flue gas temperature after condensation. Most devices rely on ambient air cooling, resulting in poor condensation effects and affecting the reliability of monitoring results.

[0010] Poor dilution accuracy: Existing dilution devices are difficult to ensure the uniform mixing of dilution gas and flue gas, resulting in poor stability and reliability of monitoring data. In addition, most devices have low control accuracy for gas flow rate, unable to accurately control the flow rates of dilution gas and flue gas, further increasing the measurement error.

[0011] In summary, the existing technologies still have deficiencies in on-line real-time monitoring, condensation efficiency, and dilution accuracy, and need to be further improved to enhance the monitoring accuracy and reliability of condensable particulate matter in stationary sources. Summary of the Invention

[0012] In view of the deficiencies of the existing technologies, the purpose of the present utility model is to provide an on-line monitoring device for condensable particulate matter based on industrial plume simulation, as well as its usage method, which have short detection time, small measurement deviation, less wall loss, and high accuracy.

[0013] The on-line monitoring device for condensable particulate matter based on industrial plume simulation provided by the present utility model has a structure as shown in Figure 1 and includes: a particulate matter classification device 1, a pipeline heating device 2, a sheath gas distribution device 3, a throttle valve, a straight condensation tube 5, a particulate matter filtering device, a gas cooling device 7, a dilution gas distribution device 8, a dilution chamber 9, a particulate matter sensor 10, and a suction pump 11 with flow rate regulation; among which:

[0014] The particulate matter classification device 1 is fixedly installed in the flue of a stationary pollution source and is used for collecting flue gas and removing large-particle-size particulate matter therein, specifically using a PM2.5 particulate matter cyclone sampler or a PM2.5 particulate matter impactor;

[0015] The pipeline heating device 2 is composed of heating resistance wires attached to the flue gas pipeline and is used for heating and maintaining the temperature of the flue gas pipeline at 100 - 130 °C;

[0016] The sheath gas distribution device 3 has its inlet connected to the flue gas pipeline and is installed between the pipeline heating device 2 and the straight condensation tube 5 and is used for uniformly distributing cooling sheath gas;

[0017] The throttle valve includes a first throttle valve 401 and a second throttle valve 402. The fronts of the first throttle valve 401 and the second throttle valve 402 are respectively connected to the sheath gas distribution device 3 and the dilution gas distribution device 8; by adjusting the valve opening degree, the flow rate is controlled to be a fixed value, so that the cooling gas enters the sheath gas distribution device 3 and the dilution gas distribution device 8 quantitatively;

[0018] The straight condenser 5 is used to condense flue gas to generate condensable particulate matter (CPM). Its upper end is connected to the sheath gas distribution device (3), and its lower end is connected to the dilution gas distribution device (8). Quartz can be selected as the material. The inside of the condenser is a vertical cylindrical structure, and the gas flows directly from top to bottom, avoiding the gas directly hitting the wall surface. The cooling source is the cooling gas that is cooled by the gas cooling device (7), filtered by the particulate filter device, and then the flow rate is regulated to a fixed value by the throttle valve and enters the cooling sheath gas of the straight condenser (5) through the sheath gas distribution device (3).

[0019] The particulate filter device includes a first particulate filter device 601 and a second particulate filter device 602. Their fronts are respectively connected to the backs of the first throttle valve 401 and the second throttle valve 402, and are used to filter and remove particulate matter in the gas provided by the gas cooling device; their backs are respectively connected to the gas cooling device 7;

[0020] The gas cooling device 7 can be a cold air blower, a semiconductor refrigerator or a compression refrigeration system, and is used to cool the air to 0°C and transport the cooled gas to the measuring device; specifically, a cold air blower, a semiconductor refrigerator or a compression refrigeration system can be adopted;

[0021] The dilution gas distribution device 8 is arranged at the lower end of the straight condenser 5 and is used to evenly distribute the dilution gas so that it is fully mixed with the original condensed flue gas. The dilution gas is the cooling gas that is cooled by the gas cooling device 7, filtered by the particulate filter device, and then the flow rate is regulated to a fixed value by the throttle valve and enters the dilution gas distribution device.

[0022] The dilution chamber 9 is a columnar tank made of metal material, and is a realization space arranged at the lower end of the dilution gas distribution device 8 to evenly distribute the dilution gas so that the dilution gas is fully mixed with the original condensed flue gas; its lower end is designed as a conical structure, and the outlet is connected to the particulate sensor 10 through a pipeline;

[0023] The particulate sensor 10 is used to measure the total concentration of particulate matter fully mixed in the dilution chamber. It is preferably a β-attenuation method particulate sensor. If the β-attenuation method particulate sensor cannot be used, a micro oscillating balance, a light scattering method particulate sensor or a light scintillation method particulate sensor can be adopted;

[0024] The air pump 11 with flow regulation is connected to the particulate sensor 10 and is used to extract and regulate the gas to be measured. Through this combination, the gas flow rate can be accurately regulated to 16 - 17 L / min to ensure the stability of the gas path flow rate of the measuring device; specifically, a diaphragm pump or a vacuum pump can be used, and a gas flow meter is provided on the pipeline;

[0025] The working process of the above-mentioned fixed-source condensable particulate matter online monitoring device is as follows:

[0026] (1) Turn on the pipeline heating device 2 to heat the flue gas pipeline and maintain it at 100 - 130 °C; start the gas cooling device 7 to cool the environment; turn on the air extraction pump 11 with flow control function, control the air extraction flow to 16 - 17 L / min, set the gas flow rates of the cooling gas and the dilution gas by adjusting the valve openings of the first throttle valve 401 and the second throttle valve 601, and start extracting flue gas;

[0027] (2) The flue gas is classified by the particulate matter classification device 1, and large - sized particulate matters in the pollution source are removed. Subsequently, the flue gas enters the straight - type condenser 5 through the flue gas pipeline heated and insulated by the pipeline heating device 2. After cooling, it is filtered by the first particulate matter filtering device 601, and the flow rate is controlled by the first throttle valve 401 to enter the sheath gas distribution device 3, and finally reaches the straight - type condenser 5. The flue gas is mixed with the cooling gas in the straight - type condenser 5 and condensed into particulate matter, and enters the dilution chamber 9;

[0028] (3) The gas cooled by the straight - type condenser 5 is filtered by the second particulate matter filtering device 602, and the flow rate is controlled by the second throttle valve 402 to enter the dilution gas distribution device 8;

[0029] (4) Through the full mixing of the dilution gas distribution device 8, the cooling gas with a given flow rate is fully mixed and diluted with the condensed flue gas in the dilution chamber 9. The mixed gas stays in the dilution chamber 9 for 5 - 10 seconds, and after cooling and drying, total particulate matter is formed;

[0030] (5) The air extraction pump 11 with flow control function controls the air extraction flow rate to enrich the particulate matter in the dilution chamber 9 on the sampling paper tape of the particulate matter sensor. The particulate matter sensor measures the total mass of the particulate matter and calculates the total particulate matter concentration in the flue gas according to parameters such as the air extraction time and the air extraction flow rate;

[0031] (6) Communicate with the CEMS through the communication port of the single - chip microcomputer or PLC, and read the data of the CEMS flue gas emission continuous monitoring system (a device that is compulsorily required by the state to be equipped for emission sources to monitor and record the emission conditions of gaseous pollutants and particulate matter from industrial emission sources) in real - time. After reading the mass concentration of filterable particulate matter, calculate the difference between the total particulate matter concentration and the mass concentration of filterable particulate matter to obtain the mass concentration of condensable particulate matter.

[0032] The beneficial effects of the present utility model are as follows:

[0033] (1) Compared with the control condensation method (EPA Method - 202), the present utility model avoids the interference of gases such as SO2 in the condensable particulate matter by diluting the flue gas, and can simulate the process of the flue gas condensing into particulate matter after actual emission and diffusing and drying in the atmospheric environment.

[0034] (2) Compared with the condensable particulate matter sampling device based on a cavity-type condenser tube (authorization announcement number CN215525244 U), the utility model can on-line monitor the mass concentration of condensable particulate matter, with a short detection time and reduced loss avoidance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of the on-line monitoring device for condensable particulate matter from a stationary source of the utility model.

[0036] Figure 2 It is a schematic structural diagram of the sheath gas distribution device of the utility model.

[0037] Figure 3 It is a schematic structural diagram of the dilution gas distribution device of the utility model.

[0038] Reference numerals in the figures: 1 is a particulate matter classification device, 2 is a pipeline heating device, 3 is a sheath gas distribution device, 401 is a first throttle valve, 402 is a second throttle valve, 5 is a straight condenser tube, 601 is a first particulate matter filtering device, 602 is a second particulate matter filtering device, 7 is a gas cooling device, 8 is a dilution gas distribution device, 9 is a dilution chamber, 10 is a particulate matter sensor, 11 is a suction pump with flow regulation, 12 is the flue gas inlet of the sheath gas distribution device, 13 is the sheath gas inlet of the sheath gas distribution device, 14 is the sheath gas gradual change pipeline of the sheath gas distribution device, 15 is the nylon wire mesh of the sheath gas distribution device, 16 is the straight condenser tube inlet of the dilution gas distribution device, 17 is the dilution gas inlet of the dilution gas distribution device, 18 is the gas distribution plate of the dilution gas distribution device, 19 is the straight condenser tube outlet of the dilution gas distribution device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The following further describes the utility model in conjunction with the drawings and embodiments:

[0040] Embodiment: Refer to Figure 1 . It includes: a particulate matter classification device 1, a pipeline heating device 2, a sheath gas distribution device 3, a first throttle valve 401, a second throttle valve 402, a straight condenser tube 5, a first particulate matter filtering device 601, a second particulate matter filtering device 602, a gas cooling device 7, a dilution gas distribution device 8, a dilution chamber 9, a particulate matter sensor 10, and a suction pump 11 with flow regulation.

[0041] In this embodiment, the particulate matter classification device 1 is a PM 2.5 particulate matter cyclone sampler or a PM 2.5 particulate matter impactor, such as a PM 2.5 cyclone sampler, a PM 2.5 inertial impact sampler.

[0042] In this embodiment, the flue gas pipeline is a pipeline made of stainless steel or other materials that can transmit gas. The pipeline heating device 2 is a heating resistance wire attached to the flue gas pipeline, and the pipeline heating device 2 maintains the flue gas pipeline at 120 °C.

[0043] In this embodiment, the first throttle valve 401 is connected to the sheath gas distribution device 3, and the second throttle valve 402 is connected to the dilution gas distribution device 8. The gas cooling device 7 cools the copper pipe through the adiabatic expansion of the compressor. The ambient air is cooled after passing through the copper pipe heat dissipation component. The generated cooling gas passes through the first particulate filter device 601 to remove particulate matter, and then by controlling the valve opening of the first throttle valve 401, the flow rate is adjusted to a fixed value and enters the sheath gas distribution device 3. Similarly, the cooling gas generated by the gas cooling device 7 passes through the second particulate filter device 602 to remove particulate matter, and then by controlling the valve opening of the second throttle valve 402, the flow rate is adjusted to a fixed value and enters the dilution gas distribution device 8, thereby achieving precise control of the flow rates of the cooling gas and the dilution gas.

[0044] In this embodiment, the structure of the sheath gas distribution device 3 is as Figure 2 shown. The device includes a flue gas inlet 12, a sheath gas inlet 13, a sheath gas tapered pipeline 14, and a nylon wire mesh 15. Among them, the flue gas inlet 12 is a continuation of the upper pipeline heating device, and the flue gas enters the sheath gas distribution device 3 therefrom. The end of the device has a tapered pipe diameter, and the pipe diameter gradually changes from the original pipe diameter to the pipe diameter inside the pipeline, forming a sheath gas tapered pipeline 14 for enabling the sheath gas to tightly and evenly wrap around the flue gas. A sheath gas inlet 13 is provided above the side of the sheath gas distribution device 3 and is connected to the first throttle valve 401, and the cooling gas enters the sheath gas distribution device 3 therefrom. The nylon wire mesh 15 is a 300-mesh nylon wire mesh placed in multiple layers in parallel, and is arranged at the lower end of the sheath gas inlet and the bottom outlet of the tapered pipeline to ensure that the cooling gas forms a laminar sheath gas protection airflow in the straight condenser 5, thereby evenly wrapping the flue gas and preventing the particulate matter in the flue gas from contacting the pipe wall and reducing the loss of particulate matter. In this embodiment, the inlet of the sheath gas distribution device 3 is connected to the flue gas pipeline, and the outlet is connected to the straight condenser 5.

[0045] In this embodiment, the straight condenser 5 is made of quartz, and a thermal insulation material is wrapped around its exterior to achieve heat preservation. The upper end of the straight condenser 5 is connected to the sheath gas distribution device 3, and the lower end is connected to the dilution chamber 9. In particular, the straight condenser 5 does not rely on the flow of cooling water to achieve the condensation effect, but realizes condensation by using the method of gas cooling inside the tube wall. The inner wall of the straight condenser 5 is designed as a slender cylindrical structure, thus effectively reducing the wall loss. The flue gas enters the condenser from the sheath gas distribution device 8 and is wrapped by the cooling gas sheath flow generated by the sheath gas distribution device, avoiding the wall loss of particulate matter in the flue gas. Inside the straight condenser 5, the cooling gas sheath flow exchanges heat fully with the flue gas, realizing the condensation of the CPM-containing flue gas and further reducing the wall loss. The condensed flue gas mixture enters the dilution chamber 9 from the lower end of the straight condenser.

[0046] In this embodiment, the structure of the dilution gas distribution device 8 is as Figure 3 shown. The device includes a straight condenser inlet 16, a dilution gas inlet 17, a gas distribution plate 18, and a straight condenser outlet 19. The straight condenser inlet 16 is inserted into the dilution gas distribution device, and its bottom end is located above the straight condenser outlet 19. The preliminarily condensed flue gas enters the dilution chamber 9 through here. The dilution gas inlet 17 is connected to the second throttle valve 402 to allow the cooling gas to enter the device. The gas distribution plate 18 is a perforated plate designed based on the annular isokinetic gas distribution method. By calculating the flow rate ratio of the flue gas and the dilution gas and the inner diameter of the dilution chamber, the aperture, number of turns, and total number of holes of the gas distribution holes are determined to ensure uniform mixing. After the flow rate of the dilution gas is controlled by the second throttle valve 402, it enters the device through the dilution gas inlet 17 and is uniformly mixed with the condensed flue gas in the dilution chamber 9 through the gas distribution plate 18.

[0047] In this embodiment, the dilution chamber 9 is made of metal, and its upper end is connected to the dilution gas distribution device 8 and the straight condenser 5. The dilution chamber 9 has a relatively large inner diameter and a relatively long length to ensure that the flue gas and the dilution gas entering the dilution chamber can be fully mixed and stay for 5 - 10 seconds in the mixing and residence section, so that they can be fully diluted, cooled, and dried to achieve the condensation and drying of particulate matter. The lower part of the dilution chamber 9 is designed as a conical structure and is connected to the particulate matter sensor 10 through a black carbon tube. The gas flow of the mixed gas and the total particulate matter condensed therein enters the black carbon pipeline at this stage and finally accumulates on the sampling paper tape of the particulate matter sensor 10.

[0048] In this embodiment, the particulate matter sensor 10 is preferably an on-line particulate matter monitoring device based on the beta attenuation method. Its air inlet is connected to the dilution chamber 9, and its air outlet is connected to an air extraction pump 11 with flow regulation. The total particulate matter generated in the dilution chamber 9 is enriched on the sampling tape, and then its mass concentration is measured. The beta attenuation method particulate matter sensor can effectively eliminate the influence of factors such as the shape and optical properties of particulate matter on the measurement of particulate matter mass concentration. When the beta attenuation method particulate matter sensor cannot be used, a micro oscillating balance, a light scattering method particulate matter sensor or a light scintillation method particulate matter sensor can be selected for measurement instead.

[0049] In this embodiment, through the air extraction pump 11 with flow regulation, preferably a diaphragm pump or a vacuum pump combined with a gas flow meter, the gas is extracted and regulated. Through this combination, the gas flow can be accurately regulated to 16.7 L / min to ensure the stability of the gas path flow of the measuring device, so that the diluted mixed particulate matter generated in the dilution chamber 9 can be effectively enriched in the particulate matter sensor 10.

[0050] In addition, the air extraction pump 11 cooperates with the first throttle valve 401 and the second throttle valve 402 to achieve precise control of the cooling gas, dilution gas, flue gas and overall flow rate. In this way, the air flow can be stabilized, and the accuracy and reliability of the measurement data can be ensured.

[0051] In this embodiment, the pipeline heating device 2, the gas cooling device 7, the particulate matter sensor 10 and the air extraction pump 11 with flow regulation are all electrically controllable devices. Through these devices, the heat preservation temperature of the flue gas, the temperature of the cooling gas and the mass concentration of the total particulate matter can be further accurately controlled for automated timing measurement, and precise regulation of the flow rate can be achieved. Through the above measures, this measuring device can achieve automated on-line monitoring and significantly improve the measurement accuracy.

[0052] The method used in this example is as follows:

[0053] Step 1: Turn on the pipeline heating device 2 to heat the flue gas pipeline and keep it at 120 °C. Start the gas cooling device 7. The temperature of the copper pipe is reduced by the adiabatic expansion of the compressor. The ambient air is cooled after passing through the copper pipe heat dissipation component. Turn on the air extraction pump 11 with flow regulation function, control the extraction flow rate to 16.7 L / min, set the gas flow rates of the cooling gas and the dilution gas by adjusting the valve openings of the first throttle valve 401 and the second throttle valve 402, and start extracting the flue gas.

[0054] Step 2: The flue gas is classified by the particle classification device 1, and the large-size particles in the pollution source are removed, and then enters the straight condenser 5 through the heated and insulated flue gas pipeline. After the cooling gas is cooled by the gas cooling device 7, it is filtered by the first particle filter device 601, and the flow rate is controlled by the first throttle valve 401 to enter the sheath gas distribution device 3, and finally reaches the straight condenser 5. The flue gas is mixed with the cooling gas in the straight condenser 5 and condensed into particles, and enters the dilution chamber 9.

[0055] Step 3: The gas cooled by the gas cooling device 7 is filtered by the No. 2 particulate matter filter device 602 and then flows into the dilution gas distribution device 8 under the control of the flow rate by the No. 2 throttle valve 402 .

[0056] Step 4: Through the full mixing of the dilution gas distribution device 8, the cooling gas of a given flow rate and the condensed flue gas are fully mixed and diluted in the dilution chamber 9. The mixed gas stays in the dilution chamber 9 for 5-10 seconds and forms total particulate matter after being cooled and dried.

[0057] Step 5: The air pump 11 with flow control function controls the air flow rate so that the particles in the dilution chamber 9 are concentrated on the sampling paper tape of the particle sensor 10. The β-ray sensor of the particle sensor 10 measures the total mass of the particles on the paper tape and calculates the total particle concentration in the flue gas based on parameters such as the air extraction time and the air extraction flow rate.

[0058] Step 6: Read the mass concentration of filterable particulate matter of the CEMS flue gas emission continuous monitoring system, and then calculate the difference between the total particulate matter concentration and the mass concentration of filterable particulate matter to obtain the mass concentration of condensable particulate matter.

[0059] The online monitoring device and method of use of the utility model can avoid the interference of gases such as SO2 in condensable particulate matter, and can simulate the process of actual flue gas emission, condensation into particulate matter, and diffusion and drying in the atmospheric environment. The measurement process of the device is automated, and can monitor and accurately measure the concentration of particulate matter online, significantly reduce measurement deviation, shorten single measurement time, and improve time resolution.

Claims

1. An online monitoring device for condensable particulate matter based on industrial plume simulation, characterized in that, It includes a particulate classification device (1), a pipeline heating device (2), a sheath gas distribution device (3), a throttle valve, a straight condenser (5), a particulate filtration device, a gas cooling device (7), a dilution gas distribution device (8), a dilution chamber (9), a particulate sensor (10), and an air extraction pump with flow control (11); among which: The particulate classification device (1) is fixedly installed in the flue of a stationary pollution source and is used for collecting flue gas and removing large-sized particulates therein; The pipeline heating device (2) is a heating resistance wire attached to the flue gas pipeline and is used for heating and maintaining the temperature of the flue gas pipeline at 100 - 130 °C; The sheath gas distribution device (3) has its inlet connected to the flue gas pipeline and is installed between the pipeline heating device (2) and the straight condenser (5) and is used for evenly distributing the cooling sheath gas; The throttle valve includes a first throttle valve (401) and a second throttle valve (402). The fronts of the first throttle valve (401) and the second throttle valve (402) are respectively connected to the sheath gas distribution device (3) and the dilution gas distribution device (8); the flow rate is controlled to be a fixed value by adjusting the valve opening degree, so that the cooling gas enters the sheath gas distribution device (3) and the dilution gas distribution device (8) quantitatively; The straight condenser (5) is used for condensing the flue gas to generate condensable particulates (CPM); its upper end is connected to the sheath gas distribution device (3), and its lower end is connected to the dilution gas distribution device (8); the inside of the condenser is a vertical cylindrical structure, and the gas flows directly from top to bottom to avoid the gas directly hitting the wall surface; the cooling source is the cooling sheath gas that is cooled by the gas cooling device (7), filtered by the particulate filtration device, and the flow rate is regulated to a fixed value by the throttle valve and enters the straight condenser (5) through the sheath gas distribution device (3); The particulate filtration device includes a first particulate filtration device (601) and a second particulate filtration device (602). Their fronts are respectively connected to the backs of the first throttle valve (401) and the second throttle valve (402) and are used for filtering and removing particulates in the gas provided by the gas cooling device; the backs are respectively connected to the gas cooling device (7); The gas cooling device (7) is used for cooling the air to 0 °C and transporting the cooled gas to the measuring device; The dilution gas distribution device (8) is arranged at the lower end of the straight condenser (5) and is used for evenly distributing the dilution gas so that it is fully mixed with the original condensed flue gas; the dilution gas is the cooling gas that is cooled by the gas cooling device (7), filtered by the particulate filtration device, and the flow rate is regulated to a fixed value by the throttle valve and then enters the dilution gas distribution device; The dilution chamber (9) is a columnar tank body made of metal material. It is arranged at the lower end of the dilution gas distribution device (8) to evenly distribute the dilution gas and is the implementation space for fully mixing the dilution gas with the original condensed flue gas; its lower end is designed as a conical structure, and the outlet is connected to the particulate sensor (10) through a pipeline; The particulate sensor (10) is used for measuring the total concentration of particulates fully mixed in the dilution chamber; The air extraction pump (11) with flow regulation is connected to the particulate matter sensor (10) and is used to extract and regulate the gas to be measured, so that the gas flow rate is regulated to 16 - 17 L / min to ensure the stable gas flow rate in the gas path of the measuring device. Specifically, a diaphragm pump or a vacuum pump is used, and a gas flow meter is provided on the pipeline.

2. The online monitoring device for condensable particulate matters according to claim 1, wherein, The particulate matter classification device (1) specifically adopts a PM2.5 particulate matter cyclone sampler or a PM2.5 particulate matter impactor.

3. The online monitoring device for condensable particulate matter according to claim 1, wherein The gas cooling device (7) specifically adopts a cooling fan, a semiconductor refrigeration machine or a compression refrigeration system.

4. The online monitoring device for condensable particulate matter according to claim 1, wherein The particulate matter sensor (10) adopts a β - attenuation method particulate matter sensor, or a micro - oscillating balance, a light scattering method particulate matter sensor or a light flashing method particulate matter sensor.

5. The online monitoring device for condensable particulate matter according to claim 1, wherein The air extraction pump (11) with flow regulation adopts a diaphragm pump or a vacuum pump, and a gas flow meter is provided on the pipeline.

6. The online monitoring device for condensable particulate matter according to claim 1, characterized in that The sheath gas distribution device (3) includes a flue gas inlet (12), a sheath gas inlet (13), a sheath gas tapered pipeline (14) and a nylon wire mesh (15); among them, the flue gas inlet (12) is a continuation part of the upper - end pipeline heating device, and the flue gas enters the sheath gas distribution device (3) therefrom; the end of the device is a tapered pipe diameter, that is, the pipe diameter gradually changes from the original pipe diameter to the pipe diameter inside the pipeline, forming a sheath gas tapered pipeline (14), so that the sheath gas can closely and evenly wrap around the flue gas; a sheath gas inlet (13) is provided above the side of the sheath gas distribution device (3), and the sheath gas inlet (13) is connected to the first throttle valve (401), and the cooling gas enters the sheath gas distribution device (3) therefrom; the nylon wire mesh (15) is a 300 - mesh nylon wire mesh placed in multiple layers in parallel, and is arranged at the lower end of the sheath gas inlet and the bottom outlet of the tapered pipeline to ensure that the cooling gas forms a laminar sheath gas protection air flow in the straight - type condenser (5), so as to evenly wrap the flue gas, prevent the particulate matter in the flue gas from contacting the pipe wall, and reduce the loss of particulate matter.

7. The online monitoring device for condensable particulate matter according to claim 1, wherein The structure of the dilution gas distribution device (8) includes a straight - type condenser inlet (16), a dilution gas inlet (17), a gas distribution plate (18) and a straight - type condenser outlet (19); the straight - type condenser inlet (16) is inserted into the dilution gas distribution device, and the bottom end is located above the straight - type condenser outlet (19); the preliminarily condensed flue gas enters the dilution chamber (9) through here; the dilution gas inlet (17) is connected to the second throttle valve (402) to allow the cooling gas to enter the device; the gas distribution plate (18) adopts a perforated plate and is designed based on the annular isokinetic gas distribution method; by calculating the flow rate ratio of the flue gas and the dilution gas and the inner diameter of the dilution chamber, the aperture diameter, the number of circles and the total number of holes of the gas distribution holes are determined to ensure uniform mixing. After the flow rate of the dilution gas is controlled by the second throttle valve (402), it enters the device through the dilution gas inlet (17) and is uniformly mixed with the condensed flue gas in the dilution chamber (9) through the gas distribution plate (18).

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