Molecular sieve adsorption performance detection device and detection method thereof

Abstract

The invention relates to a molecular sieve adsorption performance detection device and a detection method thereof in the technical field of molecular sieve detection. The molecular sieve adsorption performance detection device comprises a VOCs generator, a regulating valve, a fan, a heater and a communicating pipe, the VOCs generator and the fan are respectively communicated with two opposite side surfaces of the to-be-detected molecular sieve through two communicating pipes, the two pipes are respectively marked as a first communicating pipe and a second communicating pipe, the first communicating pipe and the second communicating pipe are coaxially arranged, the adjusting valve is arranged on the second communicating pipe and used for adjusting the air quantity, the first communicating pipe is provided with a sampling detection point A, and the second communicating pipe is provided with a sampling detection point B; a sampling detection point B is arranged on the second communicating pipe; the communicating pipe further comprises a third communicating pipe, and the two ends of the third communicating pipe communicate with the heater and the draught fan correspondingly. According to the invention, the rotating wheel can be directly tested and suggested on a project site, the product does not need to be damaged, the method is simple, convenient and rapid, the detection precision is high, the detection cost is greatly saved, the downtime of a production line is reduced to the greatest extent, and the environmental protection cost pressure of an enterprise is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve technology, specifically to a molecular sieve adsorption performance testing device and its testing method. Background Technology

[0002] In recent years, in industrial organic waste gas treatment technologies, single activated carbon adsorption is gradually being replaced by various composite new technologies, with the concentration rotor technology showing particularly outstanding performance. By achieving continuous "adsorption-high temperature desorption-cooling-adsorption" through rotation, organic waste gas is concentrated from low concentration and large volume to high concentration and small volume, greatly reducing subsequent treatment costs. VOCs treatment is truly effective, and the concentration rotor technology has been rapidly promoted and applied to waste gas treatment across all industries.

[0003] In actual project site engineering applications, the composition of exhaust gas is complex. There may be substances with unknown components and boiling points higher than the desorption temperature of the rotor that adhere to the rotor. Over time, this reduces the performance of the rotor and increases the risk of smoldering combustion.

[0004] The industry standard practice is to take samples of the rotor on-site, bring them back to the company's laboratory for processing and analysis, and determine the current state of the rotor and provide opinions by measuring the thermal weight loss of the sample at a temperature window of 200-300℃ and the difference in adsorption performance before and after heating.

[0005] Of course, there are also optimized solutions. For example, patent publication number CN112973371A discloses a simplified method for assessing the deterioration of a VOC adsorption honeycomb rotor. This method predicts the static adsorption ratio solely through organic matter accumulation measurement based on TG / DTA, without conducting a VOC static adsorption capacity test. After sampling, the degree of rotor deterioration is determined only through a sample static adsorption capacity test or based on the sample's thermal weight loss, reducing the workload of testing. However, this technology requires the accumulation of a large amount of data and extensive experience and insights in assessing deterioration to make a relatively accurate judgment, thus limiting its practicality. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a molecular sieve adsorption performance testing device and its testing method.

[0007] A molecular sieve adsorption performance testing device according to the present invention includes a VOCs generator, a regulating valve, a fan, a heater, and a connecting pipe; The VOCs generator and the fan are respectively connected to the opposite sides of the molecular sieve to be tested through two connecting pipes. The two connecting pipes are referred to as the first connecting pipe and the second connecting pipe. The first connecting pipe and the second connecting pipe are coaxially arranged. The regulating valve is located on the second connecting pipe for regulating the gas volume. The first connecting pipe is provided with a sampling detection point A, and the second connecting pipe is provided with a sampling detection point B. The connecting pipe also includes a third connecting pipe, the two ends of which are connected to the heater and the fan, respectively.

[0008] In some embodiments, the distance between the sampling and detection point A and the surface of the molecular sieve rotor to be tested is greater than or equal to 6 times the diameter of the first connecting pipe, and / or the distance between the sampling and detection point B and the surface of the molecular sieve rotor to be tested is greater than or equal to 6 times the diameter of the second connecting pipe (52).

[0009] This invention also provides a method for detecting the adsorption performance of molecular sieves, using the aforementioned molecular sieve adsorption performance detection device, comprising: S1, the first connecting pipe and the second connecting pipe are tightly and sealed to the two opposite sides of the molecular sieve rotor to be tested, and the first connecting pipe and the second connecting pipe are coaxially arranged; S2, turn on and set the heating temperature of the heater to 180-240℃, turn on the fan to blow air onto the molecular sieve rotor under test, and turn off the heater when the concentration detected at the sampling point A is less than or equal to 10mg / m³. S3, adjust the fan to draw air from the molecular sieve rotor under test, and use the regulating valve to make the wind speed at the rotor cross section in the first and second connecting pipes 2.5 m / s. Turn on the VOCs generator to inject xylene vapor of a predetermined concentration into the first pipe along with the carrier gas. By detecting the sampling concentration at the sampling detection point A and the sampling detection point B, obtain the change in the performance of the molecular sieve rotor under test over time, and plot the adsorption curve 1. S4, turn off the VOCs generator, turn on the heater and the fan. The heater is set to a temperature of 300°C. The fan continuously blows air onto the molecular sieve rotor under test until the concentration detected at the sampling point A is less than or equal to 10 mg / m³. Then turn off the heater. S5, adjust the fan to draw air from the molecular sieve rotor under test, and use the regulating valve to make the wind speed on the rotor surface in the main pipeline 2.5m / s. Turn on the VOCs generator to inject xylene vapor of a predetermined concentration into the first pipeline along with the carrier gas. By detecting the sampling concentration at the sampling detection point A and the sampling detection point B, obtain the change of the performance of the molecular sieve rotor under test over time, and plot the adsorption curve 2. S6. Select 2-3 more points along the molecular sieve rotor to be tested, and repeat steps S1-S5 to obtain multiple sets of adsorption curves 1 and 2. Judge the performance of the rotor based on the degree of agreement between adsorption curve 1 and adsorption curve 2. The root mean square error of the two curves is selected as the index for judging the degree of agreement between adsorption curve 1 and adsorption curve 2. When the root mean square error between adsorption curve 1 and adsorption curve 2 is less than or equal to 2.5, it is in the range of high degree of agreement.

[0010] In some implementations, step S6 involves averaging the data from multiple adsorption curves that show consistent trends to determine the rotor performance. If the adsorption curve 1 and adsorption curve 2 have a high degree of agreement, it indicates that the performance degradation of the rotor is caused by the collapse of the micro-pores. This performance degradation is irreversible. If the performance cannot meet the emission requirements, the rotor needs to be replaced.

[0011] If the performance of adsorption curve 2 is significantly better than that of adsorption curve 1, it indicates that the performance decline of the rotor is caused by the surface being covered and blocked by high-boiling-point substances. Periodic cleaning can restore the performance of the rotor, and there is no need to replace the rotor.

[0012] In some implementations, the connection point between the first connecting pipe and the second connecting pipe and the molecular sieve rotor to be tested is located between one-quarter and three-quarters of the rotor radius.

[0013] In some implementations, the connection point between the first connecting pipe and the second connecting pipe and the molecular sieve rotor to be tested is located at half the radius of the rotor.

[0014] In some embodiments, sampling detection point A and sampling detection point B are symmetrically arranged with respect to the molecular sieve rotor to be tested as the center, and the distance between sampling detection point A and the surface of the molecular sieve rotor to be tested is greater than or equal to 6 times the diameter of the first connecting pipe.

[0015] In some embodiments, in step S3, the concentration of xylene vapor at sampling point A before the first connecting pipe reaches the molecular sieve rotor is 200-400 mg / m³.

[0016] In some implementations, in step S5, the concentration of xylene vapor at sampling point A before the first connecting pipe reaches the molecular sieve rotor to be tested deviates from the concentration in step S3 by ≤5%.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The molecular sieve adsorption performance testing method of this invention does not require destructive operation on the rotor, ensuring the integrity of the product and maximizing the preservation of the product's VOCs adsorption capacity. Furthermore, the modular design of the testing device allows for direct on-site testing of the rotor. The entire testing process takes approximately 4-6 hours, demonstrating significant effects in cost savings and improved testing efficiency, and greatly reducing the pressure on environmental protection costs. Attached Figure Description

[0018] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a structural layout diagram of the molecular sieve adsorption performance testing device of the present invention; Figure 2 These are structural diagrams at different sampling points in the molecular sieve adsorption performance detection method of the present invention; Figure 3 This is a schematic diagram showing the degree of agreement between the first set of adsorption curves 1 and 2 of the present invention. Figure 4 This is a schematic diagram showing the degree of agreement between the second set of adsorption curves 1 and 2 of the present invention. Figure 5 This is a schematic diagram showing the degree of agreement between the third set of adsorption curves 1 and 2 of the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0020] This embodiment provides a molecular sieve adsorption performance testing device, such as... Figure 1 As shown, it mainly consists of a VOCs generator 1, a regulating valve 2, a fan 3, a heater 4, and a connecting pipe 5. In this embodiment, the connecting pipe 5 includes... VOCs generator 1 uses a plunger pump to precisely control the injection speed. The vaporization chamber temperature is adjustable up to 200℃, and the pump carrier gas rate is adjustable from 0 to 10 L / min. The output PTFE pipeline is equipped with a heating tape, with a maximum temperature of 150℃. VOCs generator 1 is connected to one side of the molecular sieve rotor 6 to be tested via a connecting pipe 5, which is referred to as the first connecting pipe 51.

[0021] The blower 3 is a high-temperature blower capable of reversing direction, with a wind pressure of 2500 Pa and a rated air volume of 50 Nm³ / h. The blower 3 is connected to the other side of the molecular sieve rotor 6 to be tested via a connecting pipe 5, which is referred to as the second connecting pipe 52. At this time, the second connecting pipe 52 and the first connecting pipe 51 are located on opposite sides of the molecular sieve rotor 6 to be tested and are coaxially arranged.

[0022] A sampling and detection point A is provided on the first connecting pipe 51, and a sampling and detection point B is provided on the second connecting pipe 52. In this embodiment, the sampling and detection point A is located at least 6 times the diameter of the first connecting pipe 51 from the surface of the molecular sieve rotor 6 under test. Similarly, the sampling and detection point B is also located at least 6 times the diameter of the second connecting pipe 52 from the surface of the molecular sieve rotor 6 under test. This ensures that the flow field at the measurement point is uniform and the results are reliable.

[0023] The regulating valve 2 is connected to the second connecting pipe 52, and precisely regulates the air volume in the gas path through bypass pressure relief. The heater 4 is connected to the fan 3 through a connecting pipe 5, providing the fan 3 with air at the corresponding preheated temperature.

[0024] According to the molecular sieve adsorption performance testing device provided in this embodiment, the specific method for testing the adsorption performance of the molecular sieve rotor to be tested is as follows: S1, see appendix Figure 1 The connection device is shown. The first connecting pipe 51 and the second connecting pipe 52 are placed on both sides of the molecular sieve rotor 6 to be tested, selected between one-quarter and three-quarters of the rotor radius, preferably at one-half of the rotor radius, avoiding the joint position, so that the end faces of the first connecting pipe 51 and the second connecting pipe 52 are tightly against the rotor. A silicone gasket is used to ensure a seal at the connection point, and a clamp is used to tighten it, while keeping the pipe axes of the first connecting pipe 51 and the second connecting pipe 52 aligned. The VOCs generator 1 is connected to the other end of the first connecting pipe 51, the fan room 3 is connected to the other end of the second connecting pipe 52, and the regulating valve 2 is connected to the second connecting pipe 52. The fan 3 and the heater 4 are connected through a third connecting pipe 53.

[0025] S2, turn on heater 4 and fan 3, set the heater temperature to 200℃, and continuously blow air onto the rotor at maximum airflow until the handheld PID detector detects a concentration of less than 10mg / m3 at sampling point A.

[0026] S3, turn off heater 4, adjust fan 3 to draw air into the rotor, and use regulating valve 2 to ensure the wind speed at the rotor cross-section in the first connecting pipe 51 and the second connecting pipe 52 is 2.5 m / s. Turn on VOCs generator 1, and inject the calculated xylene vapor of a predetermined concentration into the first pipe 51 along with the carrier gas. The predetermined concentration of xylene vapor should be between 200-400 mg / m³ when it travels from the first connecting pipe 51 to the sampling point A before the molecular sieve rotor under test. By detecting the sampling concentrations at sampling points A and B, the performance change of the molecular sieve rotor under test over time is obtained, and adsorption curve 1 is plotted.

[0027] S4, turn off VOCs generator 1, and turn on heater 4 and fan 3. Set heater 4 to 300℃, and continuously blow air through fan 3 onto the molecular sieve rotor under test until the concentration at sampling point A is less than or equal to 10mg / m³, then turn off heater 4.

[0028] S5, adjust fan 4 to draw air from the molecular sieve rotor under test, and adjust valve 2 to make the wind speed at the rotor cross-section in the first connecting pipe 51 and the second connecting pipe 52 2.5m / s. Turn on VOCs generator 1 to inject xylene vapor of a predetermined concentration into the first pipe 51 along with the carrier gas. By detecting the sampling concentration at sampling points A and B, the performance change of the molecular sieve rotor under test over time is obtained, and adsorption curve 2 is plotted. In this step, the concentration of xylene vapor at sampling point A before the molecular sieve rotor under test from the first connecting pipe 51 deviates from the concentration in step S3 by ≤5%, ensuring the accuracy of the detection data.

[0029] S6, select 2-3 more points along half the radius of the molecular sieve rotor to be tested, such as... Figure 2 As shown, repeating steps S1-S5 yields multiple sets of adsorption curves 1 and 2, as follows. Figure 3-5 As shown, the performance of the rotor is judged based on the degree of agreement between adsorption curve 1 and adsorption curve 2. The root mean square error (RMSE) of the two curves is used as the criterion for judging the degree of agreement. When the RMS error of adsorption curve 1 and adsorption curve 2 is less than or equal to 2.5, it is considered to have a high degree of agreement. The average of the data with consistent trends from multiple adsorption curves is used for the final judgment. The judgment method is as follows: If the adsorption curve 1 and adsorption curve 2 have a high degree of agreement, it indicates that the performance degradation of the rotor is caused by the collapse of the micro-pores. This performance degradation is irreversible. If the performance cannot meet the emission requirements, the rotor needs to be replaced.

[0030] If the performance of adsorption curve 2 is significantly better than that of adsorption curve 1, it indicates that the performance decline of the rotor is caused by the surface being covered and blocked by high-boiling-point substances. Periodic cleaning can restore the performance of the rotor, and there is no need to replace the rotor.

[0031] The molecular sieve adsorption performance testing method provided in this implementation does not require destructive operation of the rotor, ensuring the integrity of the product and preserving the product's VOCs adsorption capacity to the maximum extent. Moreover, the modular design of the testing device allows for direct on-site testing of the rotor. The entire process takes approximately 4-6 hours, demonstrating significant effects in cost savings and improved testing efficiency, and greatly reducing the pressure of environmental protection costs.

[0032] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0033] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A molecular sieve adsorption performance testing device, characterized in that, Includes a VOCs generator (1), a regulating valve (2), a fan (3), a heater (4), and a connecting pipe (5); The VOCs generator (1) and the fan (4) are connected to opposite sides of the molecular sieve (8) to be tested via two connecting pipes (5), respectively. The two connecting pipes (5) are referred to as the first connecting pipe (51) and the second connecting pipe (52). The first connecting pipe (51) and the second connecting pipe (52) are coaxially arranged. The regulating valve (2) is located on the second connecting pipe (52) to regulate the gas volume. The first connecting pipe (51) is provided with a sampling detection point A, and the second connecting pipe (52) is provided with a sampling detection point B. The connecting pipe (5) also includes a third connecting pipe (53), the two ends of which are connected to the heater (4) and the fan (3) respectively.

2. The molecular sieve adsorption performance testing device according to claim 1, characterized in that, The distance between sampling point A and the surface of the molecular sieve rotor to be tested is greater than or equal to 6 times the diameter of the first connecting pipe (51), and / or the distance between sampling point B and the surface of the molecular sieve rotor to be tested is greater than or equal to 6 times the diameter of the second connecting pipe (52).

3. A method for detecting the adsorption performance of molecular sieves, characterized in that, The molecular sieve adsorption performance testing device as described in claim 1 or 2 includes: S1, the first connecting pipe (51) and the second connecting pipe (52) are tightly and sealed together on opposite sides of the molecular sieve rotor to be tested, and the first connecting pipe (51) and the second connecting pipe (52) are coaxially arranged; S2, turn on and set the heating temperature of the heater (4) to 180-240℃, turn on the fan (3) to blow air onto the molecular sieve rotor to be tested, and turn off the heater (4) when the concentration detected at the sampling point A is less than or equal to 10mg / m³. S3, adjust the fan (4) to draw air from the molecular sieve rotor to be tested, and make the wind speed of the rotor section in the first connecting pipe (51) and the second connecting pipe (52) 2.5m / s through the regulating valve (2), turn on the VOCs generator (1) to inject xylene vapor of a predetermined concentration into the first pipe (51) along with the carrier gas, and obtain the change of the performance of the molecular sieve rotor to be tested over time by detecting the sampling concentration at the sampling detection point A and the sampling detection point B, and plot the adsorption curve 1; S4, turn off the VOCs generator (1), turn on the heater and the fan (3), set the temperature of the heater (4) to 300°C, and blow air through the fan (3) to the molecular sieve rotor under test until the concentration detected at the sampling point A is less than or equal to 10 mg / m³, then turn off the heater (4). S5, adjust the fan (4) to draw air from the molecular sieve rotor to be tested, and make the wind speed on the rotor surface in the main pipeline 2.5m / s through the regulating valve (2), turn on the VOCs generator (1) to inject xylene vapor of a predetermined concentration into the first pipeline (51) along with the carrier gas, and obtain the change of the performance of the molecular sieve rotor to be tested over time by detecting the sampling concentration at the sampling detection point A and the sampling detection point B, and plot the adsorption curve 2; S6. Select 2-3 more points along the molecular sieve rotor to be tested, and repeat steps S1-S5 to obtain multiple sets of adsorption curves 1 and 2. Judge the performance of the rotor based on the degree of agreement between adsorption curve 1 and adsorption curve 2. The root mean square error of the two curves is selected as the index for judging the degree of agreement between adsorption curve 1 and adsorption curve 2. When the root mean square error between adsorption curve 1 and adsorption curve 2 is less than or equal to 2.5, it is in the range of high degree of agreement.

4. The method for detecting the adsorption performance of molecular sieves according to claim 3, characterized in that, In step S6, the average value of data with consistent trends from multiple adsorption curves is used to determine the performance of the impeller. If the adsorption curve 1 and adsorption curve 2 have a high degree of agreement, it indicates that the performance degradation of the rotor is caused by the collapse of the micro-pores. This performance degradation is irreversible. If the performance cannot meet the emission requirements, the rotor needs to be replaced. If the performance of adsorption curve 2 is significantly better than that of adsorption curve 1, it indicates that the performance decline of the rotor is caused by the surface being covered and blocked by high-boiling-point substances. Periodic cleaning can restore the performance of the rotor, and there is no need to replace the rotor.

5. The method for detecting the adsorption performance of molecular sieves according to claim 3, characterized in that, The connection between the first connecting tube (51) and the second connecting tube (52) and the molecular sieve rotor to be tested is located between one-quarter and three-quarters of the rotor radius.

6. The method for detecting the adsorption performance of molecular sieves according to claim 5, characterized in that, The connection point between the first connecting pipe (51), the second connecting pipe (52), and the molecular sieve rotor to be tested is located at half the radius of the rotor.

7. The method for detecting the adsorption performance of molecular sieves according to claim 3, characterized in that, The sampling and detection point A and the sampling and detection point B are symmetrically arranged with the molecular sieve rotor to be tested as the center. The distance between the sampling and detection point A and the surface of the molecular sieve rotor to be tested is greater than or equal to 6 times the diameter of the first connecting pipe (51).

8. The method for detecting the adsorption performance of molecular sieves according to claim 3, characterized in that, In step S3, the concentration of xylene vapor at sampling point A before the molecular sieve rotor to be tested, which is located from the first connecting pipe (51), is 200-400 mg / m³.

9. The method for detecting the adsorption performance of molecular sieves according to claim 8, characterized in that, In step S5, the concentration of xylene vapor at sampling point A before the molecular sieve rotor is run from the first connecting pipe (51) to the sampling point A deviates from the concentration in step S3 by ≤5%.

Images