A kind of waste gas flue simulating fixed pollution source and its experimental method

Abstract

The present invention relates to the field of environmental monitoring technology, and discloses a simulated fixed pollution source exhaust flue and an experimental method thereof. The simulated fixed pollution source exhaust flue includes a pipe for simulating the exhaust flue, an air inlet 1 is provided at one end of the pipe, and a second air outlet 5 for sampling is provided at the other end. A water injection port 2 is provided on the side of the pipe close to the air inlet 1, and the water injection port 2 is externally connected to an injection pump 3 that can control microinjection; a first air outlet 4 is provided on the side of the pipe close to the second air outlet 5, and the first air outlet 4 is used for sampling or an external moisture detector to measure the moisture content in the pipe; the air inlet 1 includes a plurality of pipe fittings spirally connected to the inside of the pipe, and on the cross section of the pipe, the direction of the pipe fitting is tangent to the circle of the inner wall of the pipe. The present invention has a simple structure, a suitable volume, is easy to operate, and is heated throughout the experiment. By quantitatively adding various interfering substances, the changes in the exhaust gas in the flue are simulated under the condition of a smaller volume, flow rate, and reduced consumption of standard substances.

Description

Technical Field

[0001] The invention relates to the technical field of environmental monitoring, and in particular to a simulated fixed pollution source exhaust flue and an experimental method thereof. Background Art

[0002] Simulated flues are used in many industries, especially in the chemical industry and environmental engineering (management) fields. However, because they are developed according to industry needs, they all have their own characteristics and meet the needs of their research. So far, there is no simulated fixed pollution source exhaust flue for the environmental monitoring industry.

[0003] The existing simulated flues in other industries cannot meet the research needs of environmental monitoring. Their main problems include: insufficient flow control accuracy, no full-process temperature control, and the pipe and joint materials do not take into account the adsorption and reaction of the target object. Therefore, when using the simulated exhaust gas, the actual concentration of the target (pollutant) will be significantly different from the theoretical value, or the results will be affected by too many factors, making it difficult to evaluate whether the environmental monitoring process is accurately applicable to the monitoring of flue exhaust gas. Taking the monitoring of ammonia in exhaust gas as an example, the simulated flues used in the chemical industry often do not have full-process heating in the pipes, and ammonia will be adsorbed by the inner wall of the pipes; when the exhaust gas is collected at the outlet for monitoring, the recovery rate is low. However, in this case, the respective proportions of pipeline adsorption and collection process loss are unknown, making it difficult to evaluate whether the monitoring is accurate.

[0004] In addition, some existing flues have different characteristics such as being too large or having complex structures. These characteristics are not applicable to environmental monitoring research and lack specificity. Summary of the invention

[0005] In order to overcome or alleviate one or more of the above technical problems, the purpose of the present invention is to provide a simulated fixed pollution source exhaust flue and an experimental method thereof. The flue has a simple structure, a suitable volume, and is easy to operate. A simulation experiment that is more in line with the actual situation can be carried out on the exhaust flue of the fixed pollution source to cooperate with the research on efficient, accurate, and anti-interference environmental monitoring methods.

[0006] The present invention provides the following technical solutions:

[0007] A simulated fixed pollution source exhaust flue comprises a pipe for simulating the exhaust flue, wherein an air inlet (1) is provided at one end of the pipe, and a second air outlet (5) for sampling is provided at the other end; a water injection port (2) is provided on the side of the pipe close to the air inlet (1), and the water injection port (2) is externally connected to an injection pump (3) capable of controlling microinjection; a first air outlet (4) is provided on the side of the pipe close to the second air outlet (5), and the first air outlet (4) is used for sampling or an external moisture detector to measure the moisture content in the pipe; the air inlet (1) comprises a plurality of pipe fittings spirally connected to the inside of the pipe, and in the cross section of the pipe, the direction of the pipe fittings is tangent to the circle of the inner wall of the pipe.

[0008] According to some embodiments, both ends of the pipeline are sealed by flanges (7) and sealing rings, and the air inlet (1) and the second air outlet (5) are both arranged on the flanges (7) at both ends.

[0009] According to some embodiments, a mixing block (8) is provided in the pipeline.

[0010] According to some embodiments, the material used to make the mixing block (8) is selected from 316L stainless steel.

[0011] According to some embodiments, the material used to make the pipe is selected from electro-polished 316L stainless steel.

[0012] On the other hand, the present invention also provides an experimental method for simulating a flue gas duct of a fixed pollution source as described above, which comprises the following steps:

[0013] S1: setting the temperature of the simulated flue, heating the pipe using a temperature-controlled heating jacket (6), and controlling the temperature inside the simulated flue to the set temperature;

[0014] S2: Connect zero-grade air through one of the pipes in the air inlet (1) to set the flow rate, generally 0.3L / min to 1L / min, and heat-wash the pipe for 10 to 60 minutes;

[0015] S3: Before the formal experiment, if there is a need for calibration, the calibration process is performed, that is, the micro-stepping motor is used to control the injection pump (3) to inject liquid pure water at a set flow rate, and the water addition rate is calculated and calibrated;

[0016] S4: The gases to be added such as the simulated flue gas are connected to different pipes of the air inlet (1) respectively; different standard gases are controlled by an external electronic mass flow meter at standard flow rates and enter the pipe of the simulated flue gas from the pipe of the air inlet (1);

[0017] S5: Start the exhaust gas simulation experiment. After a plurality of different standard gases enter the simulated flue, they are quickly mixed under the spiral action of the air inlet (1). If liquid pure water needs to be added, it is added at a constant speed through the water injection port (2) and the injection pump (3) controlled by the micro stepping motor;

[0018] S6: Using the first air outlet (4) as a sampling port for the simulated flue, collecting waste gas samples for further analysis, and exhausting them through the second air outlet (5).

[0019] According to some embodiments, the calculation steps of step S3 are as follows:

[0020] S31: Calculate the water addition rate and moisture content The relationship is calculated by the following formula:

[0021]

[0022] Where V is the flow rate of water injected into the syringe, unit: mL / min; ρ is the density of water at ambient temperature, unit: g / mL; V i is the standard flow rate of standard gas i, unit: L / min; 18 is the molar mass of water, unit: g / mol; 22.4 is the standard molar volume of ideal gas, unit: L / mol;

[0023] S32: Conduct actual measurement to verify the water addition rate and moisture content The first air outlet (4) is externally connected to a moisture detector using a resistance-capacitance method;

[0024] S33: The simulated flue is controlled at a set temperature, and zero-grade air is introduced into the set inflow, and pure water is introduced according to the calculated water addition rate. After the reading of the moisture detector is stable, the moisture content is recorded; then the water addition rate is changed and the moisture content is recorded;

[0025] S34: Compare the moisture content calculated in step S31 with the moisture content actually measured in step S33 to obtain a calibration coefficient.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The simulated fixed pollution source exhaust flue provided by the present invention has a simple structure, suitable volume, and is easy to operate. The pipeline is made of electro-polished 316L stainless steel, which greatly reduces the adsorption points of the target object, which is conducive to improving the accuracy of the monitoring results of the target objects with strong activity or strong adsorption.

[0028] The flow rate of the simulated flue is adjustable, and the adjustable flow rate simulates the conditions of an actual pipeline. It can allow the complex exhaust gas conditions inside the actual pipeline to enter through gases with "known" substances, flow rates, temperatures and other information, and simulate their changes in the pipeline, including physical changes, chemical changes, etc., thereby achieving an exhaust flue simulation that is close to the actual situation.

[0029] The simulated exhaust gas has a known amount added to facilitate calculation of the degree of change. The result is helpful in evaluating the actual exhaust gas discharge from the pipeline, developing and optimizing environmental monitoring methods, confirming chemical conditions, and environmental treatment projects.

[0030] The pipeline experiment is heated throughout the whole process, which not only simulates the high-temperature flue conditions, but also greatly reduces the adsorption of many target objects at high temperatures. The flow rate controlled by MFC is generally tens of milliliters per minute, and the total flow rate in the pipeline is generally not more than 5 liters per minute, but due to the small size of the pipeline, the linear velocity belongs to the linear velocity range of the actual pipeline, which can play a good simulation effect; and in this case, the consumption rate of standard gas is low, which is economical.

[0031] In the experiment, by quantitatively adding various interfering substances and water, it is possible to simulate changes in the exhaust gas in the flue, such as chemical reaction changes, at a smaller volume, flow rate, and with less consumption of standard substances.

[0032] The present invention is also convenient for combined monitoring, and the influence of other substances on the target object can be found through the "1+x" method. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of a waste gas flue simulating a fixed pollution source provided in Example 1 of the present invention.

[0034] Figure 2 for Figure 1 Distribution diagram of the air inlet at the left end of the duct.

[0035] Figure 3 for Figure 1 Schematic diagram of the first air outlet in FIG.

[0036] Figure 4 Another schematic diagram of a waste gas flue simulating a fixed pollution source provided in an embodiment of the present invention.

[0037] Figure 5 A flow chart of an experimental method for simulating a waste gas flue from a fixed pollution source provided in an embodiment of the present invention.

[0038] Figure 6 The relationship between the set water addition rate and the moisture content is provided in the embodiment of the present invention.

[0039] Figure 7The effect of NO on ammonia recovery rate provided in the examples of the present invention (n=3).

[0040] Figure 8 The effect of NO2 on ammonia recovery rate provided in the embodiment of the present invention (n=3).

[0041] Fig. 9 The effect of SO2 on ammonia recovery rate provided in the embodiment of the present invention (n=3).

[0042] Fig.10 The effect of CO on ammonia recovery rate provided in the embodiment of the present invention (n=3).

[0043] In the figure:

[0044] 1. Air inlet; 2. Water injection port; 3. Injection pump; 4. First air outlet; 5. Second air outlet; 6. Temperature control heating jacket; 7. Flange; 8. Mixing block. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0046] The present invention will be further described below in conjunction with the accompanying drawings.

[0047] Example 1

[0048] like Figure 1 The simulated fixed pollution source exhaust flue provided in this embodiment includes a pipe for simulating the exhaust flue. The total length of the pipe is 80 cm and the inner diameter is 5 cm. The material is electro-polished 316L stainless steel. The inner wall of the pipe is electro-polished to minimize the adsorption of target pollutant exhaust gas pollutants. The outer wall of the pipe is wrapped with heating wire and heat-insulating material to control the temperature in the pipe. The temperature control range is: room temperature ~ 180°C.

[0049] The left end of the pipeline is the air inlet 1, and the right end is the second air outlet 5 of the mixed gas. The second air outlet 5 can be used as a sampling port for simulated exhaust gas and as an exhaust port for exhaust gas. A water injection port 2 is provided near the air inlet 1 of the pipeline. The water injection port 2 is connected to an injection pump 3 controlled by a micro-stepping motor to inject liquid pure water into the pipeline. A first air outlet 4 is provided near the second air outlet 5 of the pipeline. The first air outlet 4 is not only used as a sampling port for simulated exhaust gas, but also used to connect an external moisture detector to measure the moisture content in the pipeline. A mixing block 8 with a diameter close to the inner diameter of the pipeline is placed in the pipeline to quickly mix the mixed gas.

[0050] The specifications of some parts are as follows:

[0051] The air inlet 1 includes seven 1 / 8-inch pipe fittings, such as Figure 2 , seven pipe fittings are connected in a spiral manner in the pipeline. On the pipeline section, the direction of the pipe fittings is tangent to the circle of the inner wall of the pipeline. The pipe fittings are external threads (1 / 8 inch pipe or 6mm outer diameter pipe fittings), and need to be equipped with corresponding nuts and sealing rings (1 / 8 inch or 6mm pipe). The angle of the pipe fitting cutting into the left end of the pipeline is 45 degrees; the number of pipe fittings is also determined according to the number of types of standard gases required for the experiment.

[0052] The outer diameter of the water injection port 2 is 1 cm, and the protruding height is 4.0 cm;

[0053] The injection pump 3 is a injection pump controlled by a micro-stepping motor, which injects water at a certain flow rate;

[0054] like Figure 3 The first air outlet 4 protrudes outward by 1.5 cm and is equipped with a sealing nut with an inner diameter of 1.0 cm;

[0055] Second air outlet 5: 5 cm long, 1 / 4 inch outer diameter;

[0056] The control temperature range of the temperature-controlled heating jacket 6 is room temperature to 220°C.

[0057] The distance between the air inlet 1 and the water injection port 2 is 20 cm; the distance between the first air outlet 4 and the second air outlet 5 is 20 cm.

[0058] like Figure 5 , the simulation experiment process is as follows:

[0059] (1) The temperature of the simulated flue is set, and the temperature control heating jacket 6 is used to heat the pipe, and the temperature inside the simulated flue is controlled to the set temperature.

[0060] (2) Connect zero-grade air through one of the air inlets 1 to set the flow rate, generally 0.3 L / min to 1 L / min, and heat-flush the pipeline for 10 to 60 minutes.

[0061] (3) Before the formal experiment, if verification is required, the water addition rate should be calculated and verified.

[0062] Before calibration, the pipeline must be heated and flushed to ensure that there is no debris inside that may affect the results, but the flushing time can be as short as possible, such as 10 minutes. Calibration does not need to be performed before each formal test. Generally, it is calibrated once the simulated flue is moved, or when it has not been used for a long time (one month), or once every two months.

[0063] To simulate the moisture in the flue, water vapor is not injected, but liquid pure water is injected at a set flow rate through an electronic injection pump 3. When the water flows into the simulated flue, the flue temperature is sufficient to vaporize it instantly, and mix it with the airflow and flow away, thereby achieving the purpose of simulating exhaust gas with a certain moisture content, and then calculation is performed;

[0064] First, calculate the water addition rate and moisture content The relationship can be calculated by the following formula:

[0065]

[0066] Where V is the flow rate of water injected into the syringe, mL / min;

[0067] ρ is the density of water at ambient temperature, g / mL;

[0068] Vi is the flow rate of standard gas i at standard conditions (0°C, 1 atm), L / min;

[0069] 18 is the molar mass of water, g / mol;

[0070] 22.4 is the standard volume of an ideal gas, L / mol.

[0071] Since the control accuracy of the injection pump 3 may be poor, or the efficiency of pure water vaporization may be poor, it is necessary to at least verify the water addition rate and the moisture content of the water through actual measurement. relationship.

[0072] Actual measurement: The second air outlet 5 is emptied, and the first air outlet 4 is connected to a moisture probe of the resistance-capacitance method. The simulated flue is controlled at a set temperature, and zero-grade air is introduced at a set inflow, and pure water is introduced according to the calculated water addition rate. After the probe reading is stable, the moisture content is recorded; then the water addition rate is changed and the moisture content is recorded.

[0073] Finally, the calculated moisture content is compared with the measured value to obtain the calibration coefficient. In this step, the moisture content is measured by the resistance-capacitance method, and the moisture content is well controlled; at least the water addition rate is set to have a good linear relationship with the measured value (the correlation coefficient is not less than 0.995).

[0074] like Figure 6 To set the relationship between water addition rate and moisture content.

[0075] (4) During the formal experiment, the gas that needs to be added, such as a simulated flue gas (such as zero-grade air, standard gas), is connected to different pipes of the air inlet 1 respectively.

[0076] Different standard gases are controlled by electronic mass flow meters (MFC) at standard flow rates and enter the pipe of the simulated flue from the pipe fittings of the air inlet 1. The joints of the 7 air inlet 1 are all threaded and tilted toward the center to ensure that the inflowing gases can be optimally mixed.

[0077] (5) After completing steps (1) and (2), perform exhaust gas simulation. After each gas enters the simulated flue, it is Figure 2 ) under the condition of rapid mixing, under most experimental conditions, the actual measurement can be mixed. If you need to add liquid substances such as water, add them at a constant speed through the water injection port 2.

[0078] (6) After the experiment, the first air outlet 4 in the figure is generally used as the sampling port of the simulated flue to collect the exhaust gas sample. The second air outlet 5 at the rightmost end of the flue in the figure is used for exhaust.

[0079] Example 2

[0080] This embodiment uses the simulated fixed pollution source exhaust flue provided in Example 1 to conduct an experiment on ammonia-containing simulated exhaust gas (ammonia standard gas and zero-grade air are added at a constant speed), and sulfuric acid solution is used for absorption at the outlet, and ion chromatography is used for analysis. The quantitative result of the ion chromatograph is used as the measured value, and the recovery rate is obtained by comparing it with the theoretical value. Before formal sampling, the flow rate is set to pass the standard gas and dilution gas for 20 minutes. Sampling is repeated 3 times. The results are shown in Table 1 below:

[0081] Table 1 Sampling related records

[0082]

[0083] Ammonia is a relatively active substance and is prone to adsorption loss on the inner wall of the pipe. As a target, it is particularly challenging to test the effectiveness of the simulated flue. From the above experimental results, it can be seen that the simulated flue has a good mixing effect and almost no ammonia loss is caused by the inner wall.

[0084] Table 2 below lists some experimental results of simulating ammonia waste gas. This example uses the simulated fixed pollution source waste gas flue provided in Example 1 to conduct experiments on simulated ammonia waste gas (ammonia standard gas and zero-grade air are added at a constant rate). The outlet is absorbed by sulfuric acid solution and analyzed by ion chromatography. The quantitative result of the ion chromatograph is used as the measured value, and the recovery rate is obtained by comparing it with the theoretical value. Before formal sampling, the flow rate is set to pass the standard gas and dilution gas for 20 minutes. Sampling is carried out continuously for 10 times. In one group of experiments, no water was added; in the other group, pure water was added at a constant rate to make the moisture content of the simulated waste gas 28%.

[0085] Table 2 Effect of moisture on ammonia monitoring

[0086]

[0087] It can be seen from the above table that adding gaseous water to ammonia standard gas will not cause ammonia loss.

[0088] Common acidic gases (NO, NO2, SO2, etc.) in the exhaust gas of stationary pollution sources may react with ammonia. Some reactions are particularly rapid, which may cause the collected samples to be less representative and the ammonia measurement results to be low.

[0089] Using simulated flue and sampling tube, different interfering gases were added under non-humidification and humidification conditions, and the recovery rate of ammonia was measured to investigate the influence of different interfering gases on the recovery rate of ammonia.

[0090] Example 3

[0091] This example provides an experimental simulation flue temperature of 180°C, no catalyst is added to the flue, and the fixed sampling flow rate is 0.3L / min. Under each condition, the sampling is repeated 3 times. The moisture content of the humidified simulated exhaust gas is 28%. The effects of common interfering gases such as NO, NO2, SO2 and CO on ammonia can be found in Figure 7 to Figure 10 Since hydrogen chloride and chlorine are highly corrosive and can cause significant damage to electronic mass flow meters, their effects on ammonia in the simulated flue were not investigated.

[0092] Under the experimental conditions, when the simulated exhaust gas is dry, ammonia will basically not react with NO and SO2 in the simulated flue, and has no effect on the recovery rate of ammonia; NO2 has a certain effect on the recovery rate of ammonia. Under the humidified state, SO2 and NO2 will significantly reduce the recovery rate of ammonia, NO will slightly reduce the recovery rate of ammonia, and CO has no effect on the recovery rate of ammonia.

[0093] The above results are helpful to analyze the impact of various acidic gases on ammonia in high-temperature pipelines, and contribute to the advancement of chemical engineering, environmental engineering and environmental monitoring technology.

[0094] Examples 2 to 3 simulated the pipeline exhaust gas experiment, which is more in line with the actual situation. In addition, the pipeline uses electropolished 316L stainless steel, which greatly reduces the adsorption points of the target object; the whole pipeline heating not only simulates the situation of the high-temperature flue, but also at high temperatures, the adsorption of many targets will be greatly reduced. The flow rate controlled by MFC is generally tens of milliliters per minute, and the total flow rate in the pipeline generally does not exceed 5 liters per minute, but due to the small size of the pipeline, the linear velocity belongs to the linear velocity range of the actual pipeline, which can play a good simulation effect; and in this case, the consumption rate of the standard gas is low, which is economical.

[0095] By quantitatively adding various interfering substances and water, it is possible to simulate changes in flue gas, such as reactions, at a smaller volume, flow rate, and with reduced consumption of standard substances. It is also convenient to combine monitoring and discover the impact of other substances on the target through the "1+x" method.

[0096] Thus, users can be guided to develop monitoring methods that are efficient, accurate and have strong anti-interference capabilities.

[0097] Example 4

[0098] In Example 1, the second air outlet 5 is fixedly connected to the pipeline, and the experimental operation is relatively complicated. Therefore, based on Example 1, this embodiment uses a flange 7 to connect the second air outlet 5 on the side of the second air outlet 5 of the pipeline. Figure 4 , and multiple mixing blocks 8 for mixing the gas are placed in the pipeline, and a polytetrafluoroethylene gasket is used in the middle of the flange 7. The mixing block 8 is made of 316L stainless steel. If the gas flow rate is set, or it is difficult to mix due to differences in gas components, the mixing block 8 can be placed in the flue to mix the combined gas more evenly.

[0099] Compared with Example 1, Example 4 is simpler to manufacture and install, and can be easily disassembled and cleaned when the simulated flue is seriously polluted.

[0100] The experimental steps of this embodiment are the same as those of embodiment 1.

[0101] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An experimental method based on simulating a waste gas flue of a fixed pollution source, the simulated waste gas flue of a fixed pollution source comprises a pipe for simulating the waste gas flue, an air inlet (1) is provided at one end of the pipe, and a second air outlet (5) for sampling is provided at the other end, a water injection port (2) is provided on the side of the pipe close to the air inlet (1), and the water injection port (2) is externally connected to an injection pump (3) capable of controlling microinjection; a first air outlet (4) is provided on the side of the pipe close to the second air outlet (5), and the first air outlet (4) is used for sampling or externally connected to a moisture detector, and the moisture detector is used to measure the moisture content in the pipe; the air inlet (1) comprises a plurality of pipe fittings spirally connected to the inside of the pipe, and on the cross section of the pipe, the direction of the pipe fittings is tangent to the circle of the inner wall of the pipe, characterized in that: The method comprises the following steps: S1: setting the temperature of the simulated flue, heating the pipe using a temperature-controlled heating jacket (6), and controlling the temperature inside the simulated flue to the set temperature; S2: Connect zero-grade air through one of the pipes in the air inlet (1), introduce zero-grade air at a rate of 0.3 L / min to 1 L / min, and heat-wash the pipe for 10 to 60 minutes; S3: Before the formal experiment, a calibration process is performed, that is, a micro-stepping motor is used to control the injection pump (3) to inject liquid pure water at a set flow rate, and the liquid pure water addition rate is calculated and calibrated; the specific steps are as follows: S31: Calculate the water addition rate and the moisture content of the water The relationship is calculated by the following formula: ， Wherein, V is the flow rate of water injected by the injection pump, unit: mL / min; ρ is the density of water at ambient temperature, unit: g / mL; Vi is the standard flow rate of standard gas i, unit: L / min; 18 is the molar mass of water, unit: g / mol; 22.4 is the gas molar volume under standard conditions, unit: L / mol; S32: Conduct actual measurement to verify the water addition rate and moisture content The first air outlet (4) is externally connected to a moisture detector using a resistance-capacitance method; S33: The simulated flue is controlled at a set temperature, and zero-grade air is introduced at a set flow rate, and pure water is introduced at a calculated water addition rate. After the reading of the moisture detector is stable, the moisture content is recorded; then the water addition rate is changed and the moisture content is recorded; S34: Compare the moisture content calculated in step S31 with the moisture content actually measured in step S33 to obtain a calibration coefficient; S4: connecting the standard gases to be added to simulate the flue to different pipe fittings of the air inlet (1) respectively; the different standard gases are controlled by an external electronic mass flow meter at standard flow rates and enter the pipe of the simulated flue from the pipe fittings of the air inlet (1); S5: Start the exhaust gas simulation experiment. After a plurality of different standard gases enter the simulated flue, they are quickly mixed under the spiral action of the air inlet (1), and liquid pure water is added at a constant speed through the water injection port (2) and the injection pump (3) controlled by the micro-stepping motor; S6: Using the first air outlet (4) as a sampling port for the simulated flue, collecting waste gas samples for further analysis, and exhausting them through the second air outlet (5).

2. The experimental method based on simulating the exhaust flue of a fixed pollution source according to claim 1 is characterized in that: The two ends of the pipeline are sealed by flanges (7) and sealing rings, and the air inlet (1) and the second air outlet (5) are respectively arranged on the flanges (7) at the two ends.

3. The experimental method based on simulating the exhaust flue of a fixed pollution source according to claim 2 is characterized in that: A mixing block (8) is arranged in the pipeline.

4. The experimental method based on simulating the exhaust flue of a fixed pollution source according to claim 3 is characterized in that: The material used to make the mixing block (8) is selected from 316L stainless steel.

5. The experimental method based on simulating the exhaust flue of a fixed pollution source according to claim 1 is characterized in that: The material used to make the pipe is selected from electro-polished 316L stainless steel.

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