An evaluation device and test method for filtering the ammonia content of absorber off-gas

Abstract

This invention discloses an evaluation device and test method for the ammonia content escaping from a filter absorber, relating to the field of ammonia content detection. It includes two separate, temperature- and humidity-controlled test chambers. The first test chamber contains a first fan, and an inlet duct is connected to a first temperature and humidity sensor. The outlet of the first fan is connected to the inlet of the filter absorber via a first pipe. The outlet of the filter absorber is connected to a ventilation duct. The inlet end of the ventilation duct is located in the first test chamber, and the outlet end is located in the second test chamber. A second temperature and humidity sensor is connected to the outlet of the ventilation duct, and an ammonia detector is connected to the outlet end of the ventilation duct via a sampling pipe. The test method includes the following steps: purging and preheating; adjusting the temperature and humidity in the test chamber, adjusting the airflow of the filter absorber, starting a stopwatch, and beginning the test; the filter absorber operates at the set airflow; observing and recording changes in ammonia concentration; purging, and ending the test. This device and test method simulate a real environment, offering high precision and greater stability and accuracy.

Description

Technical Field

[0001] This invention relates to the field of ammonia content detection technology, specifically to an evaluation device and test method for the ammonia content escaping from a filter absorber. Background Technology

[0002] As an important filtration element in collective protective equipment, the filter absorber is installed in the filtration and ventilation system. It relies on the impregnated carbon and smoke filter layer in the filter absorber to purify the contaminated air into fresh air, thereby playing the role of filtering and purifying the air.

[0003] However, as the core filtration and purification material of filter absorbers, impregnated carbon typically uses ammonia water as the solvent for the impregnation component during its preparation. This ammonia water system of impregnated carbon has the problem of ammonia gas escaping during use. Ammonia gas is corrosive and irritating to human skin and respiratory organs. The ammonia odor escaping during the use of filter absorbers can seriously affect the comfort of using protective equipment. Therefore, the detection of the escaped ammonia content is an important indicator for the quality inspection of filter absorbers.

[0004] Current detection methods only test the impregnated carbon packed in the filter absorber. The chemical absorption method for ammonia concentration determination measures the total ammonia content emitted from the impregnated carbon over a certain period, but it cannot provide real-time feedback on the ammonia emission curve over time. Existing technologies for detecting the ammonia content emitted from impregnated activated carbon use air sweeping to monitor ammonia emission over time in real time, which can be used to evaluate ammonia emission during the impregnated carbon development process. However, using the impregnated carbon sample, the packing material of the filter absorber, as the evaluation object cannot accurately reflect the ammonia emission situation during actual use of the filter absorber.

[0005] Due to variations in the filling process of filter absorbers, such as the filling density, filling method, filling height, and material inhomogeneity of impregnated carbon, it is impossible to evaluate the actual use of filter absorbers through ammonia release tests of impregnated carbon. This makes it impossible to comprehensively simulate actual usage scenarios. Therefore, in order to more accurately simulate the ammonia release of filter absorbers under actual usage conditions, it is necessary to adopt a filter absorber ammonia release evaluation device and test method that better meets the usage conditions. Summary of the Invention

[0006] To address the problems of irritating odors released by current filter absorbers during use, which cause significant discomfort to users and severely impact the user experience, and the lack of an evaluation device and testing method for the amount of ammonia released by filter absorbers during use, as well as the inability to accurately assess the ammonia content emitted by filter absorbers solely through the evaluation of ammonia release from impregnated carbon, this invention provides an evaluation device and testing method for the ammonia content emitted by filter absorbers.

[0007] This invention is achieved using the following techniques: This invention provides an evaluation device for the ammonia content escaping from a filter absorber, comprising a first test chamber and a second test chamber that are at constant temperature and humidity and are not interconnected. The first test chamber is equipped with a first fan, and an air inlet pipe is installed at the air inlet of the first fan. A first temperature and humidity sensor is connected inside the air inlet pipe. The air outlet of the first fan is connected to the inlet of the filter absorber through a first pipe. The outlet of the filter absorber is connected to a ventilation pipe. The inlet end of the ventilation pipe is located in the first test chamber, and the outlet end is located in the second test chamber. An exhaust pipe connected to the outside is provided on the wall of the second test chamber. A filter absorber and a second fan are installed on the exhaust pipe. A second temperature and humidity sensor is connected inside the outlet end of the ventilation pipe. An ammonia detector is connected to the outlet end of the ventilation pipe through a sampling pipe.

[0008] During implementation, two separate, temperature- and humidity-controlled test chambers are used, one for temperature control and the other for humidity control. The first test chamber is used to regulate the temperature and humidity environment required for the test. The temperature range of the first test chamber is RT~70℃, ±2℃, and the relative humidity control range is 10~100%RH, ±5%. The first test chamber is used to replenish the filter absorber at maximum airflow (500m³ / h). 3 The test chamber contains a first fan, whose inlet is equipped with an inlet duct. The inlet duct contains a first temperature and humidity sensor to detect the temperature and humidity of the incoming air. The outlet of the first fan is connected to the inlet of a filter absorber via a first pipeline. The airflow range of the filter absorber is 40~500 m³ / h. 3 / h, an airflow measuring device is installed on the first pipeline, which is connected to a dust collection system controller placed in the second test chamber. This controller controls the airflow of the filter absorber. Placing the dust collection system controller in the second test chamber facilitates airflow adjustment and extends its service life. The outlet of the filter absorber is connected to a ventilation duct. The inlet end of the ventilation duct is located in the first test chamber, and the outlet end is located in the second test chamber. The walls of the second test chamber are equipped with an exhaust duct that connects to the outside environment to discharge the gas in the second test chamber. A filter absorption device and a second fan are installed on the exhaust duct to absorb harmful gases discharged into the second test chamber. The ventilation duct is sealed and extends from the first test chamber into the second test chamber. The temperature in the second test chamber is higher than the dew point temperature of the test temperature and humidity to prevent the test airflow from cooling down. Condensation can lead to lower test results and also prevents condensation from entering the testing instrument and affecting the accuracy of the test. At the same time, the second test chamber is used to provide the working environment for the ammonia detector. The temperature range of the second test chamber is RT~70℃, ±2℃, which is lower than the allowable operating temperature of the ammonia detector. The ventilation duct passes through the first test chamber and the second test chamber in a sealed manner to ensure the stability of the temperature and humidity of each chamber. A second temperature and humidity sensor is connected to the outlet end of the ventilation duct to detect the temperature and humidity of the air outlet. The outlet end of the ventilation duct is connected to the ammonia detector through a sampling tube. One end of the sampling tube is connected to the ammonia detector, and the other end extends into the ventilation duct. The ammonia detector is an infrared gas detector or an electrochemical gas detector with a range of 0~300ppm, a resolution of ≤0.5ppm, and an accuracy of ≤1%.

[0009] A method for testing the ammonia content escaping from a filter absorber includes the following steps: S1: Turn on the second fan and the filter absorption device and keep them running until the end of the test. Turn on the ammonia detector and purge it with high-purity nitrogen. Preheat for at least 30 minutes.

[0010] S2: Adjust the temperature and humidity in the first test chamber to the test temperature and humidity of the filter absorber, with a temperature of 32~55℃ and a humidity of 29~95%; adjust the temperature in the second test chamber to be higher than the dew point temperature of the test airflow. After the temperature and humidity in the chambers stabilize, turn on the combined protection system controller and adjust the flow rate of the first fan to the set air volume, which is 40~400m³ / h. 3 / h, and start the stopwatch to begin the experiment.

[0011] S3: Adjust the controller of the air conditioning system to ensure that the filter absorber operates at the set airflow during the test; observe the ammonia detector and record the ammonia concentration change value and corresponding time. In this test method, the airflow at the set airflow passes through the filter absorber, and the ammonia concentration at the outlet of the filter absorber is detected in real time by the ammonia detector; when the escaping ammonia concentration is 0 for 15 consecutive minutes, the test is stopped; when the highest escaping ammonia concentration in the test is less than the maximum allowable concentration specified in the index, and the escaping ammonia concentration value reaches equilibrium or decreases and does not rise again within 15 minutes, the test is stopped; otherwise, the test is continued for 8 hours, and data is continuously collected.

[0012] S4: After the test, purge the ammonia detector and sampling tube with high-purity nitrogen, and purge the ventilation duct with clean air for at least 30 minutes to end the test.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The device and test method for evaluating the ammonia content emitted by a filter absorber provided by this invention innovatively evaluate the ammonia content emitted by the filter absorber under different airflow and temperature and humidity conditions, and perform online real-time ammonia concentration detection. It can simulate the real situation of ammonia content emitted by the filter absorber under high temperature and high humidity conditions. By using two environmental test chambers, the control test environment and ammonia concentration detection are separated, which can protect the ammonia detector from damage caused by the entry of crystal water or excessive operating temperature. It ensures that the airflow will not condense during the test, and guarantees the accuracy and reliability of the test results. At the same time, it can control the constant temperature and humidity airflow of the entire device under high temperature and high humidity test conditions, and can realize a scientific and reasonable evaluation of the ammonia content emitted by the filter absorber under different airflow and temperature and humidity conditions, so that the entire device has higher precision and more stable performance.

[0014] The entire device is simple and convenient to operate, with a reasonable layout, reliable performance, and strong practicality. It can be used to simulate real-world operating environments, improving work efficiency and providing theoretical guidance for quality control during the research and development and production of filter absorbers. The test method can detect and record test data online in real time, with a high degree of automation and safety. It can evaluate whether the ammonia content released from the filter absorber meets the requirements and guide the improvement of the filter absorber's packing materials. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention.

[0016] In the diagram: 1-First temperature and humidity sensor; 2-Ventilation duct; 3-First fan; 4-Airflow measuring device; 5-Filter absorber; 6-Air collection and protection system controller; 7-Ammonia detector; 8-Sampling tube; 9-Second temperature and humidity sensor; 10-First test chamber; 11-Second test chamber; 12-Inlet duct; 13-Second fan; 14-Filter absorber; 15-Exhaust duct; L1-First pipeline. Detailed Implementation

[0017] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0018] A device for evaluating the ammonia content escaping from a filter absorber, such as... Figure 1 As shown: a first test chamber 10 and a second test chamber 11, which are at constant temperature and humidity and not interconnected. The first test chamber 10 is used to regulate the constant temperature and humidity environment required for the test. The temperature range of the first test chamber 10 is RT~70℃, ±2℃, and the relative humidity control range is 10~100%RH, ±5%. The first test chamber 10 is used to replenish the filter absorber in a timely manner at the maximum airflow (500m³ / h). 3 The test chamber 10 contains a first fan 3, whose inlet is equipped with an inlet pipe 12. A first temperature and humidity sensor 1 is connected to the inlet pipe 12 to detect the temperature and humidity at the inlet. The outlet of the first fan 3 is connected to the inlet of a filter absorber 5 via a first pipe L1. The airflow range of the filter absorber 5 is 40~500 m³ / h. 3 / h, in this embodiment, 40, 200, and 400m are used. 3 / h, an airflow measuring device 4 is installed on the first pipeline L1, and a dust collection system controller 6 placed in the second test chamber 11 is connected to the first pipeline L1 to control the airflow of the filter absorber. The placement of the dust collection system controller 6 in the second test chamber 11 facilitates airflow adjustment and extends its service life. The outlet of the filter absorber 5 is connected to the ventilation pipe 2. The inlet end of the ventilation pipe 2 is located in the first test chamber 10, and the outlet end is located in the second test chamber 11. The second test chamber 11 has an exhaust pipe 15 connected to the outside. A filter absorber 14 and a second fan 13 are installed on the exhaust pipe 15 to ensure the working environment in the second test chamber and protect the health of the staff. That is, the ventilation pipe 2 is sealed to exit the first test chamber 10 and enter the second test chamber 11. The temperature in the second test chamber 11 is higher than the dew point temperature of the test temperature and humidity. To prevent condensation of the test airflow, which could lead to lower test results, and to prevent condensate from entering the testing instrument and affecting test accuracy, the second test chamber 11 provides the working environment for the ammonia detector 7. The temperature range of the second test chamber 11 is RT~70℃, ±2℃, which is lower than the allowable operating temperature of the ammonia detector. The ventilation duct 2 passes through the chamber in a sealed manner to ensure the stability of the temperature and humidity of the first test chamber 10 and the second test chamber 11. A second temperature and humidity sensor 9 is connected to the outlet end of the ventilation duct 2 to detect the temperature and humidity of the air outlet. The outlet end of the ventilation duct 2 is connected to the ammonia detector 7 through a sampling tube 8. One end of the sampling tube 8 is connected to the ammonia detector 7, and the other end extends into the ventilation duct 2. The ammonia detector 7 is an infrared gas detector or an electrochemical gas detector with a range of 0~300ppm, a resolution of ≤0.5ppm, and an accuracy of ≤1%.

[0019] A method for testing the ammonia content escaping from a filter absorber includes the following steps: S1: Turn on the second fan 13 and the filter absorption device 14 to ensure the working environment in the second test chamber. Turn on the ammonia detector 7 and purge the ammonia detector 7 and sampling tube 8 with high-purity nitrogen. At the same time, preheat for at least 30 minutes.

[0020] S2: In this embodiment, to meet various standard requirements, six different temperatures and humidity levels were tested, as detailed below: Sample Environment 1: According to GJB 5834-2006 "Limits of Harmful Gas Concentration in Armored Vehicle Cabins", the climatic conditions for detecting harmful gas concentration in armored vehicle cabins shall comply with the provisions of 6.1 in GJB 5421-2005. The test conditions in 6.1 of GJB 5421-2005 refer to GJB 59.63-96. During the armored vehicle test, the ambient temperature shall not be lower than 32℃ and the relative humidity shall not be lower than 65%.

[0021] According to GJB 1835-93 "General Design Requirements for Armored Vehicle Human-Machine-Environment System", the relative humidity of armored vehicles should be controlled within the range of 30% to 70%.

[0022] To strengthen the assessment, based on the above standards, the normal operating test conditions for armored vehicles are set at 32℃ and 70% relative humidity.

[0023] Sample Environment 2: According to GJB 282.4-95 "Environmental Conditions for Armored Vehicles - Working and Storage Environment Humidity", the high temperature and high humidity index for the working environment of armored vehicles is usually set at a relative humidity of 95% and a corresponding temperature of 30℃. According to GJB 59.63-96 "Test Procedures for the Ventilation and Cooling Performance of Armored Vehicles", the ambient temperature during armored vehicle testing shall not be lower than 32℃ and the relative humidity shall not be lower than 65%.

[0024] Based on the provisions of GJB 282.4-95 and GJB 59.63-96 regarding the working temperature and humidity of armored vehicles, the highest temperature and humidity conditions are selected, namely, a damp heat test condition with a temperature of 32℃ and a relative humidity of 95%.

[0025] Sample Environment 3: Based on the highest ambient temperature and relative humidity of each province in China in Appendix C of GB 50264-2013 "Code for Design of Thermal Insulation Engineering of Industrial Equipment and Pipelines", and the daily variations of temperature and relative humidity corresponding to the 1% working extreme value of high temperature in 150 stations across the country in GJB 1172.2-91 "Climatic Extreme Values ​​of Military Equipment - Surface Climate", the daily variations of temperature and relative humidity corresponding to the 1% working extreme value of high temperature in the country.

[0026] Based on the above standard provisions, the extreme high temperature and high humidity test conditions are adopted, with a temperature of 45℃ and a relative humidity of 80%.

[0027] Sample Environment 4: According to the technical specifications of the filter absorber, the maximum operating temperature of the filter absorber is 55℃. Based on the damp heat test conditions of 32℃ and 95% relative humidity, the corresponding moisture content is 32.1g / kg. Therefore, the humidity at 55℃ is 29%.

[0028] Therefore, a temperature of 55℃ and a relative humidity of 29% were selected as the high-temperature test conditions.

[0029] Sample Environment 5: According to GJB 150.3A-2009 "Laboratory Environmental Test Methods for Military Equipment Part 3: High Temperature Test", the filter absorber was stored at 70°C for 48 hours. After returning to normal temperature, the ammonia release test was conducted at a temperature of 32°C and a relative humidity of 70%.

[0030] To ensure a more rigorous assessment, the experiment was conducted at a temperature of 32℃ and a relative humidity of 95%.

[0031] Sample Environment 6: The filter absorber was subjected to impact and vibration tests according to GJB 150.18A-2009 "Laboratory Environmental Test Methods for Military Equipment - Part 18: Impact Test" and GJB 150.16A-2009 "Laboratory Environmental Test Methods for Military Equipment - Part 16: Vibration Test". Then, an ammonia release test was conducted under the normal operating test conditions for armored vehicles, with a temperature of 32℃ and a relative humidity of 70%.

[0032] To further tighten the testing, the filter absorber was subjected to impact and vibration, and then the test was conducted under conditions of 32°C and 95% relative humidity.

[0033] The test environments and corresponding dew points of samples 1-6 are summarized in the table below:

[0034] Adjust the temperature and humidity inside the first test chamber 10 to the test temperature and humidity of the filter absorber 5. Adjust the temperature inside the second test chamber 11 to be higher than the dew point temperature of the test airflow. After the temperature and humidity inside the chamber stabilize, turn on the air collection and protection system controller 6, adjust the flow rate of the first fan 3 to the set air volume, and start the stopwatch at the same time to begin the test.

[0035] S3: Adjust the controller 6 of the air collection and protection system to ensure that the filter absorber 5 operates at the set air volume during the test; observe the ammonia detector 7 and record the change value of ammonia concentration and the corresponding time; stop the test when the ammonia concentration is 0 for 15 consecutive minutes; stop the test when the highest ammonia concentration in the test is less than the maximum allowable concentration specified in the index, and the ammonia concentration value reaches equilibrium or decreases and does not rise again within 15 minutes; otherwise, continue the test for 8 hours.

[0036] S4: After the test, purge the ammonia detector 7 and sampling tube 8 with high-purity nitrogen, and purge the ventilation pipe 2 with clean air for at least 30 minutes to end the test.

[0037] The test results were processed, and the ammonia escaping from the filter absorber was expressed as the weighted average concentration over the test period and the highest concentration after short-term contact. The calculation process is as follows: 1) Weighted average concentration of ammonia released during the test period According to Appendix B of GJB 5834-2006 "Limits for Concentration of Hazardous Gases in Armored Vehicle Cabins", the weighted average concentration during the test period is calculated using formula (1): E = (C1T1 + C2T2 + ... + C n T n ) / T (1) In the formula: E represents the weighted average concentration of ammonia released during the test period, in ppm; T represents the total test time, in minutes; C1, C2, ... C n Representing T1, T2, ... T respectively n Ammonia concentration (ppm) corresponding to the time; T1, T2, ...T n Indicates the sampling time, in minutes.

[0038] 2) Short-term exposure to the highest escaping ammonia concentration According to Appendix B of GJB 5834-2006 "Limits of Hazardous Gas Concentrations in Armored Vehicle Cabins", the maximum short-term exposure concentration is calculated using formula (2): E max =(C1T1+C2T2+…+C 15 T 15 ) / 15 (2) In the formula: E max —Weighted average concentration of ammonia escaping over 15 minutes, including the highest concentration value, in ppm; C1, C2, ... C 15 —respectively T1, T2, ...T 15 Ammonia concentration (ppm) corresponding to the time; T1, T2, ...T 15 —Sampling time, in minutes.

[0039] 3) Maximum ammonia escape concentration The highest concentration of ammonia released was read directly from the test record.

[0040] The samples were evaluated using the test method of this invention: I. Under different temperature and humidity test conditions, take 200m 3 An ammonia release test was conducted on a certain type of filter absorber with an air volume of / h. The test results are shown in the table below.

[0041]

[0042] II. Under different temperature and humidity test conditions, take 400m 3 An ammonia emission test was conducted on a certain type of filter absorber with an air volume of / h. Considering that the impact vibration had little effect on the sample, the test was conducted at 400m³ / h. 3 The evaluation test that discarded this condition in the / h air volume is shown in the table below.

[0043]

[0044] III. Under different temperature and humidity test conditions, take 40m 3 An ammonia release test was conducted on a certain type of filter absorber with an air volume of / h. The test results are shown in the table below.

[0045]

[0046] As shown in the table above, under different temperatures and humidity levels and under different pretreatment conditions, the weighted average concentration and the highest short-time contact concentration of a certain type of filter absorber showed significant differences during the test time. This confirms that the evaluation device and test method can accurately provide the evaluation environment, and the test method is reasonable and feasible.

[0047] The scope of protection claimed by this invention is not limited to the specific embodiments described above. Moreover, for those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An evaluation device for the ammonia content escaping from a filter absorber, characterized in that: The test chamber includes a first test chamber (10) and a second test chamber (11) that are kept at constant temperature and humidity and are not interconnected. The first test chamber (10) is equipped with a first fan (3). An air inlet pipe (12) is installed at the air inlet of the first fan (3). A first temperature and humidity sensor (1) is connected inside the air inlet pipe (12). The air outlet of the first fan (3) is connected to the inlet of a filter absorber (5) through a first pipe (L1). A system controller (6) for the combined protection system is connected to the first pipe (L1) and placed inside the second test chamber (11). The outlet of the filter absorber (5) is connected to a ventilation pipe (2). The inlet end of the ventilation pipe (2) is located in the first test chamber (10), and the outlet end is located in the second test chamber (11). The temperature in the second test chamber (11) is higher than the dew point temperature of the test temperature and humidity. 1) The cabin wall is provided with an exhaust duct (15) that communicates with the outside. The exhaust duct (15) is equipped with a filter absorption device (14) and a second fan (13). The outlet end of the ventilation pipe (2) is connected to a second temperature and humidity sensor (9). The outlet end of the ventilation pipe (2) is connected to an ammonia detector (7) through a sampling pipe (8). The temperature range of the first test chamber (10) is RT~70℃, ±2℃, and the relative humidity control range is 10~100%RH, ±5%. The first test chamber replenishes the airflow required by the filter absorber when it is running continuously at maximum airflow, and keeps the airflow temperature and humidity constant and within the specified values ​​of the test. The second test chamber (11) is used to provide the working environment for the ammonia detector. The temperature range of the second test chamber (11) is RT~70℃, ±2℃, which is lower than the allowable working temperature of the ammonia detector.

2. The device for evaluating the ammonia content escaping from a filter absorber according to claim 1, characterized in that: An air volume measuring device (4) is installed on the first pipeline (L1).

3. The device for evaluating the ammonia content escaping from a filter absorber according to claim 1, characterized in that: One end of the sampling tube (8) is connected to the ammonia detector (7), and the other end extends into the ventilation tube (2).

4. The device for evaluating the ammonia content escaping from a filter absorber according to claim 1, characterized in that: The ammonia detector (7) has a range of 0~300ppm, a resolution of ≤0.5ppm, and an accuracy of ≤1%.

5. The test method for evaluating the ammonia content escaping from the filter absorber according to claim 1, characterized in that: Includes the following steps: S1: Turn on the second fan (13) and the filter absorption device (14), turn on the ammonia detector (7) and purge with high-purity nitrogen, while preheating for at least 30 minutes; S2: Adjust the temperature and humidity inside the first test chamber (10) to the test temperature and humidity of the filter absorber (5), adjust the temperature inside the second test chamber (11) to be greater than the dew point temperature of the test airflow, and after the temperature and humidity inside the chamber are stable, turn on the air collection system controller (6), adjust the flow rate of the first fan to the set air volume, and turn on the stopwatch at the same time to start the test. S3: Adjust the controller (6) of the air collection and protection system to ensure that the filter absorber (5) operates at the set air volume during the test; observe the ammonia detector (7) and record the ammonia concentration change value and the corresponding time; S4: After the test, purge the ammonia detector (7) and sampling tube (8) with high-purity nitrogen, and purge the ventilation tube (2) with clean air for at least 30 minutes to end the test.

6. The test method for evaluating the ammonia content escaping from a filter absorber according to claim 5, characterized in that: In step S3, the test is stopped when the ammonia concentration is 0 for 15 consecutive minutes; the test is stopped when the highest ammonia concentration is less than the maximum allowable concentration specified in the index, and the ammonia concentration reaches equilibrium or decreases and does not rise again within 15 minutes; otherwise, the test is continued for 8 hours.

7. The test method for an evaluation device for the ammonia content escaping from a filter absorber according to claim 5, characterized in that: In step S2, the temperature is set to 32~55℃, and the humidity to 29~95%; the air volume is set to 40~400m³ / h. 3 / h.

Images