System and method for detecting hydrogen sulfide in waste acid sulfuration arsenic removal tail gas

Abstract

The invention relates to a system for detecting hydrogen sulfide in waste acid sulfuration arsenic removal tail gas, which comprises a primary filter, and the primary filter is sequentially connected with a first three-way electromagnetic valve, a sucking pump, a gas cooling dryer, a second three-way electromagnetic valve, a terminal filter, a gas path converter, a sample gas regulating valve and a gas mixing chamber through a pipeline, a hydrogen sulfide gas detector is fixedly connected in the gas mixing chamber, the first three-way electromagnetic valve and the second three-way electromagnetic valve are communicated with a compressed air source through pipelines, the compressed air source is connected with a dilution regulating valve through a pipeline, and the dilution regulating valve is communicated with the gas mixing chamber. Under the condition that a hydrogen sulfide gas detector is not changed, high-concentration hydrogen sulfide gas is measured, and meanwhile, the measuring range adjusting degree can be changed along with process requirements.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen sulfide gas detection technology, and specifically relates to a hydrogen sulfide detection system in the tail gas of acid sulfidation for arsenic removal, as well as a method for detecting hydrogen sulfide using the system. Background Technology

[0002] Hydrogen sulfide is a highly toxic, flammable, colorless gas with a rotten egg odor. Its hazards are mainly manifested in three aspects: human health, production safety, and the ecological environment. Exposure to an environment containing a certain concentration of hydrogen sulfide can cause poisoning or even death; it may explode when the explosive limit is reached; and when released into the atmosphere, it generates acidic substances, exacerbating the formation of acid rain.

[0003] Arsenic-containing waste acid generated during the purification of flue gas from copper smelting production requires the addition of excess sodium hydrosulfide to remove the arsenic as a precipitate. Hydrogen sulfide gas with a wide concentration variation is generated during the reaction; this gas needs to be collected, removed by adding alkaline solution, and then discharged in an organized manner after testing confirms that the emissions are below the limits set by the "Odor Pollutant Emission Standard".

[0004] Currently, the copper smelting industry uses two main methods for hydrogen sulfide detection: indirect and direct detection. Indirect detection is affected by factors such as measurement distance, wind force, and wind direction, resulting in large measurement errors and providing only reference data. Existing direct detection methods suffer from corrosion of analytical instruments due to factors such as the presence of dust and moisture in the gas and the wide variation in concentration range, or pipe blockage caused by the accumulation of water and dust over prolonged use. Furthermore, the continuous contact between the hydrogen sulfide gas detector and the gas during detection can reduce the sensor's lifespan. Therefore, we propose a hydrogen sulfide detection system for arsenic removal tail gas from acid sulfidation processes. Summary of the Invention

[0005] The purpose of this invention is to provide a hydrogen sulfide detection system in the tail gas of arsenic removal from acid sulfidation, which has the feature of extending the service life of the hydrogen sulfide gas detector.

[0006] To achieve the above objectives, the present invention provides a hydrogen sulfide detection system for arsenic removal tail gas from acid sulfidation, comprising a primary filter. The primary filter is sequentially connected via pipes to a first three-way solenoid valve, a vacuum pump, a gas cooling dryer, a second three-way solenoid valve, a terminal filter, a gas converter, a sample gas regulating valve, and a gas mixing chamber. A hydrogen sulfide gas detector is fixedly connected within the gas mixing chamber. Both the first and second three-way solenoid valves are connected via pipes to a compressed air source. The compressed air source is connected via pipes to a dilution regulating valve, which is connected to the gas mixing chamber.

[0007] The technical features of this invention also include:

[0008] A first air filter pressure reducing valve is connected to the pipe connecting the compressed air source to the first three-way solenoid valve, and a second air filter pressure reducing valve is connected to the pipe connecting the compressed air source to the second three-way solenoid valve. The second air filter pressure reducing valve is connected to a dilution regulating valve through a branch pipe. The gas converter is connected to a nitrogen source and a standard hydrogen sulfide source through pipes respectively.

[0009] The gas-cooled dryer is connected to a manual drain valve via a pipe.

[0010] The primary filter and the first three-way solenoid valve are connected by a corrosion-resistant pipeline with electric heating.

[0011] Another technical solution adopted in this invention is a hydrogen sulfide detection system in the tail gas of arsenic removal from acid sulfidation, which is implemented according to the following method:

[0012] Step 1: Start the exhaust pump to draw the process exhaust gas into the system from the primary filter. After being processed by the primary filter, gas cooling dryer and terminal filter, and with the flow rate regulated by the sample gas regulating valve, the exhaust gas is sent into the gas mixing chamber to detect the hydrogen sulfide concentration in the exhaust gas.

[0013] Step 2: Change the connection status of the first three-way solenoid valve and the second three-way solenoid valve, introduce compressed air from the compressed air source into the system to purge each component, and at the same time, the compressed air enters the gas mixing chamber to activate the hydrogen sulfide gas detector.

[0014] Step 3: After purging, repeat step 1 for testing;

[0015] Step 4: During the detection process, when the hydrogen sulfide gas detector needs to adjust the range of the hydrogen sulfide detection system, adjust the opening of the dilution regulating valve to change the range of the hydrogen sulfide detection system.

[0016] The method is further characterized by:

[0017] In step 1, when adjusting the flow rate of the sample gas regulating valve, the flow rate is maintained at 0.2 L / min to 0.5 L / min;

[0018] In step 2, when purging the primary filter through the first three-way solenoid valve, the pressure of compressed air is controlled to be maintained at 0.2 MPa to 0.25 MPa. When purging the terminal filter to the gas mixing chamber through the second three-way solenoid valve, the pressure of compressed air is controlled to be maintained at 10 Pa to 30 Pa. During the purging process, ensure that the gas flow rate through the sample gas regulating valve is consistent with the flow rate through the sample gas regulating valve in step 1.

[0019] In step 1, the first three-way solenoid valve connects the primary filter and the air pump, and the second three-way solenoid valve connects the gas cooling dryer and the terminal filter.

[0020] In step 2, the first three-way solenoid valve connects the primary filter and the first air filter pressure reducing valve, and the second three-way solenoid valve connects the second air filter pressure reducing valve and the terminal filter.

[0021] Step 4 involves adjusting the measurement range, which is performed as follows:

[0022] Step 4.1: Adjust the opening of the dilution regulating valve according to the target range;

[0023] Step 4.2: Close the connection between the gas converter and the terminal filter, then connect the nitrogen source to the gas mixing chamber until the hydrogen sulfide gas detector reading stabilizes and then determine the zero point of the detection system.

[0024] Step 4.3: After determining the zero point, turn off the nitrogen source and then turn on the standard hydrogen sulfide source. Introduce hydrogen sulfide into the gas mixing chamber through the sample gas regulating valve. At the same time, turn on the compressed air source and introduce air into the gas mixing chamber through the dilution regulating valve until the hydrogen sulfide gas detector reading stabilizes. Then determine the maximum value of the detection system's range.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. After the detection is completed, compressed air can be used to purge the components in the system, which can effectively avoid the shortened service life of the hydrogen sulfide gas detector caused by long-term exposure to hydrogen sulfide environment and extend the detection life of the device.

[0027] 2. When the concentration of hydrogen sulfide gas discharged from the upstream device is too high, a certain amount of air can be continuously added to the gas mixing chamber by adjusting the opening of the dilution regulating valve, thereby reducing the concentration of hydrogen sulfide gas in the gas mixing chamber and expanding the range of the detection system. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the connection structure of the hydrogen sulfide detection system in the tail gas of the arsenic removal system after acid sulfidation according to the present invention.

[0029] In the diagram: 1. Primary filter; 2. First three-way solenoid valve; 3. Air pump; 4. Gas cooling dryer; 5. Second three-way solenoid valve; 6. Terminal filter; 7. Sample gas regulating valve; 8. Hydrogen sulfide gas detector; 9. Gas mixing chamber; 10. First air filter pressure reducing valve; 11. Dilution regulating valve; 12. Manual drain valve; 13. Gas path switching valve; 14. Nitrogen source; 15. Standard hydrogen sulfide source; 16. Compressed air source; 17. Second air filter pressure reducing valve. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0031] Example 1:

[0032] like Figure 1 As shown, a hydrogen sulfide detection system for arsenic removal tail gas from sludge treatment in waste acid includes a primary filter 1. The primary filter 1 is connected in sequence via pipes to a first three-way solenoid valve 2, a vacuum pump 3, a gas cooling dryer 4, a second three-way solenoid valve 5, a terminal filter 6, a gas converter 13, a sample gas regulating valve 7, and a gas mixing chamber 9. A hydrogen sulfide gas detector 8 is fixedly connected inside the gas mixing chamber 9. The first three-way solenoid valve 2 and the second three-way solenoid valve 5 are both connected via pipes to a compressed air source 16. The compressed air source 16 is connected via pipes to a dilution regulating valve 11, which is connected to the gas mixing chamber 9.

[0033] A first air filter pressure reducing valve 10 is connected to the pipe that connects the compressed air source 16 to the first three-way solenoid valve 2, and a second air filter pressure reducing valve 17 is connected to the pipe that connects to the second three-way solenoid valve 5. The second air filter pressure reducing valve 17 is connected to the dilution regulating valve 11 through a branch pipe. The gas converter 13 is connected to a nitrogen source 14 and a standard hydrogen sulfide source 15 through pipes respectively.

[0034] During operation, the system uses a vacuum pump 3 to draw exhaust gas from the process exhaust port into the system. The exhaust gas then passes sequentially through a primary filter 1, a first three-way solenoid valve 2, a gas cooling dryer 4, a second three-way solenoid valve 5, a terminal filter 6, a gas path switching valve 13, and a sample gas regulating valve 7 before entering the gas mixing chamber 9 for testing. In this process, the primary filter 1 and the terminal filter 6 are used to remove dust from the exhaust gas, and the gas drying cooler 4 removes moisture from the exhaust gas to prevent dust and moisture from affecting the test results.

[0035] After the system has been performing detection work for a period of time, compressed air is used to purge the system interior by changing the connection status of the first three-way solenoid valve 2 and the second three-way solenoid valve 5. Purge reduces dust in the primary filter 1 and the terminal filter 6, restoring their filtering capacity. At the same time, purging also reduces the contact between the hydrogen sulfide gas detector 8 and the hydrogen sulfide, preventing the hydrogen sulfide gas detector 8 from malfunctioning.

[0036] Example 2:

[0037] Based on Example 1:

[0038] like Figure 1 As shown, the gas-cooled dryer 4 is connected to a manual drain valve 12 via a pipe.

[0039] During long-term use, moisture in the exhaust gas will accumulate continuously inside the gas-cooled dryer 4. When there is too much moisture, it will affect the drying effect of the gas-cooled dryer 4. Therefore, a manual drain valve 12 is installed to periodically drain the moisture from the gas-cooled dryer 4 and maintain its drying capacity.

[0040] Example 3:

[0041] Based on Example 1:

[0042] The primary filter (1) is connected to the first three-way solenoid valve (2) through a corrosion-resistant pipeline with electric heating.

[0043] Hydrogen sulfide gas has high reactivity and adsorption properties. When the sample gas is transported in pipelines at room temperature or low temperature, it is easily adsorbed onto the inner wall of the pipeline, thus affecting the accuracy of the detection. Therefore, this system uses electrically heated, corrosion-resistant pipelines to heat the gas during transportation, preventing hydrogen sulfide gas from adhering to the inner wall of the pipeline.

[0044] Working principle:

[0045] Testing process:

[0046] During the testing process, the exhaust pump 3 is first started to draw the emitted exhaust gas into the system after it has passed through the primary filter 1, thus initially removing dust from the exhaust gas. Moisture is removed from the exhaust gas as it passes through the gas cooling dryer 4, and dust is further removed by the terminal filter 6. After treatment, the exhaust gas is sent to the gas mixing chamber 9 for detection by the hydrogen sulfide gas detector 8.

[0047] Purging procedure:

[0048] After a single test is completed, the first three-way solenoid valve 2 is changed to connect the air filter regulator 10 and the primary filter 1, and the second three-way solenoid valve 5 is changed to connect the air filter regulator 10 and the terminal filter 6. Then, the compressed air source 16 provides compressed air to the two air filter regulators 10. After the pressure of the compressed air is adjusted, it is sent into the first three-way solenoid valve 2 and the second three-way solenoid valve 5 for purging.

[0049] Range adjustment procedure:

[0050] When the measured value detected by the hydrogen sulfide gas detector 8 reaches its maximum value in a single test, the connection between the gas path switching valve 13 and the terminal filter 6 is first cut off. Then, nitrogen is introduced into the gas mixing chamber 9 through the nitrogen source 14. The nitrogen is used to purge the hydrogen sulfide gas remaining in the gas mixing chamber 9, so that the hydrogen sulfide gas detector 8 is in an environment free of hydrogen sulfide gas, thereby determining the zero point of the detection range of this system.

[0051] Then, the maximum value of the range adjustment is determined. The flow rate of compressed air supplied by the dilution regulating valve 11 is calculated by combining the hydrogen sulfide concentration corresponding to the maximum value of the range with the flow rate of the standard hydrogen sulfide source and the hydrogen sulfide concentration corresponding to the maximum detection value of the hydrogen sulfide gas detector 8. Then, the opening of the dilution regulating valve 11 is adjusted to introduce compressed air into the gas mixing chamber 9 through the dilution regulating valve 11. When the reading of the hydrogen sulfide gas detector 8 is maintained at the maximum value, the opening of the dilution regulating valve 11 is maintained, thereby changing the maximum value of the measurement system and completing the range adjustment.

[0052] In the subsequent detection process, the compressed air is adjusted to the corresponding dilution ratio by the dilution flow meter 11 and then continuously introduced into the gas mixing chamber 9 to dilute the sample gas. After the gas is fully mixed, the actual concentration of hydrogen sulfide in the current exhaust gas can be calculated by the concentration displayed by the hydrogen sulfide gas detector 8 and the ratio of the diluted gas.

Claims

1. A system for detecting hydrogen sulfide in arsenic removal tail gas from acidic wastewater treatment, characterized in that, The system includes a primary filter (1), which is connected in sequence via pipes to a first three-way solenoid valve (2), a vacuum pump (3), a gas cooling dryer (4), a second three-way solenoid valve (5), a terminal filter (6), a gas converter (13), a sample gas regulating valve (7), and a gas mixing chamber (9). A hydrogen sulfide gas detector (8) is fixedly connected inside the gas mixing chamber (9). The first three-way solenoid valve (2) and the second three-way solenoid valve (5) are both connected to a compressed air source (16) via pipes. The compressed air source (16) is connected to a dilution regulating valve (11) via pipes. The dilution regulating valve (11) is connected to the gas mixing chamber (9).

2. The hydrogen sulfide detection system in the tail gas of arsenic removal from acidic waste gas as described in claim 1, characterized in that, The compressed air source (16) is connected to the first three-way solenoid valve (2) via a pipe connected to a first air filter pressure reducing valve (10), and to the second three-way solenoid valve (5) via a pipe connected to a second air filter pressure reducing valve (17). The second air filter pressure reducing valve (17) is connected to a dilution regulating valve (11) via a branch pipe. The gas converter (13) is connected to a nitrogen source (14) and a standard hydrogen sulfide source (15) via pipes.

3. The hydrogen sulfide detection system in the tail gas of arsenic removal from acidic waste gas as described in claim 2, characterized in that, The gas-cooled dryer (4) is connected to a manual drain valve (12) via a pipe.

4. The hydrogen sulfide detection system in the tail gas of arsenic removal from acidic waste gas treatment according to claim 2, characterized in that, The primary filter (1) and the first three-way solenoid valve (2) are connected by a corrosion-resistant pipeline that is electrically heated.

5. A method for detecting hydrogen sulfide, characterized in that, The hydrogen sulfide detection system for arsenic removal tail gas from acid sulfidation as described in any one of claims 2 to 4 shall be implemented in accordance with the following method: Step 1: Start the vacuum pump (3) to draw the exhaust gas from the process into the system through the primary filter (1), and after being processed by the primary filter (1), gas cooling dryer (4) and terminal filter (6), the flow rate is regulated by the sample gas regulating valve (7) and then sent into the gas mixing chamber (9) to detect the hydrogen sulfide concentration in the tail gas. Step 2: Change the connection status of the first three-way solenoid valve (2) and the second three-way solenoid valve (5), introduce compressed air from the compressed air source (16) into the system to purge each component, and at the same time, the compressed air enters the gas mixing chamber (9) to activate the hydrogen sulfide gas detector (8). Step 3: After purging, repeat step 1 for testing; Step 4: When the hydrogen sulfide gas detector (8) needs to adjust the range of the hydrogen sulfide detection system during the detection process, adjust the opening of the dilution regulating valve (11) to change the range of the hydrogen sulfide detection system.

6. The hydrogen sulfide detection method according to claim 5, characterized in that, In step 1, when the sample gas regulating valve (7) adjusts the flow rate, the flow rate is maintained at 0.2 L / min to 0.5 L / min; In step 2, when the primary filter (1) is purged by the first three-way solenoid valve (2), the pressure of compressed air is controlled to be maintained at 0.2 MPa to 0.25 MPa. When the terminal filter (6) to the gas mixing chamber (9) is purged by the second three-way solenoid valve (5), the pressure of compressed air is controlled to be maintained at 10 Pa to 30 Pa. During the purging process, it is ensured that the gas flow rate through the sample gas regulating valve (7) is consistent with the flow rate through the sample gas regulating valve (7) in step 1.

7. The hydrogen sulfide detection method according to claim 5, characterized in that, In step 1, the first three-way solenoid valve (2) connects the primary filter (1) and the air pump (3), and the second three-way solenoid valve (5) connects the gas cooling dryer (4) and the terminal filter (6). In step 2, the first three-way solenoid valve (2) connects the primary filter (1) and the first air filter pressure reducing valve (10), and the second three-way solenoid valve (5) connects the second air filter pressure reducing valve (17) and the terminal filter (6).

8. The method for detecting hydrogen sulfide according to claim 5, characterized in that, The range adjustment in step 4 is performed according to the following steps: Step 4.1: Adjust the opening of the dilution regulating valve (11) according to the target range; Step 4.2: Close the connection between the gas converter (13) and the terminal filter (6), and then connect the nitrogen source (14) to the gas mixing chamber (9) until the reading of the hydrogen sulfide gas detector (8) stabilizes and then determine the zero point of the detection system. Step 4.3: After determining the zero point, turn off the nitrogen source (14) and then turn on the standard hydrogen sulfide source (15). Input hydrogen sulfide into the gas mixing chamber (9) through the sample gas regulating valve (7). At the same time, turn on the compressed air source (16) and input air into the gas mixing chamber (9) through the dilution regulating valve (11) until the reading of the hydrogen sulfide gas detector (8) stabilizes. Then determine the maximum value of the detection system range.

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