Method for controlling content of sulfur dioxide in dry quenching flue gas

Abstract

The invention relates to a method for controlling the content of sulfur dioxide in dry quenching flue gas, and belongs to the technical field of quenching flue gas desulfurization methods. According to the technical scheme, the average value of sulfur dioxide in the current hour is used as a control parameter for starting and stopping the dry quenching desulfurization device, spraying of the dry quenching desulfurization device is forbidden within the time interval of the hourly time + 10 minutes, spraying is automatically stopped by a system after the spraying time reaches 3 minutes, and meanwhile, an alarm value of the concentration of sulfur dioxide in the hour is set. The method has the beneficial effects that automatic start and stop of the dry quenching desulfurization device are controlled by the current hour concentration value of sulfur dioxide, so that on the premise of completing the sulfur dioxide concentration control, the consumption of a desulfurizing agent is reduced, the waste of the desulfurizing agent is avoided, and the cost is reduced. The problem that the concentration of sulfur dioxide exceeds the standard due to the fact that personnel cannot find the blockage of the dry quenching desulfurization device in time is avoided, and the blockage frequency of the dry quenching desulfurization device is reduced.

Description

Technical Field

[0001] This invention relates to a method for controlling the sulfur dioxide content in dry quenching flue gas, belonging to the technical field of desulfurization methods for quenching flue gas. Background Technology

[0002] National environmental protection policies stipulate that the sulfur dioxide content in flue gas emitted from dry quenching environments should be controlled at 80 mg / m³. 3 The following requirement for environmental Class A enterprises is 50mg / m³. 3 To achieve this target, our plant adopted a method of injecting a highly active calcium-based desulfurizer into the dust collection flue gas in the dry quenching environment to reduce the sulfur dioxide content. After a period of use, this method has proven to be very effective in reducing the sulfur dioxide concentration in the dust collection flue gas. Initially, our plant used the instantaneous sulfur dioxide concentration as the control value for the automatic start and stop of the desulfurization unit. When the instantaneous sulfur dioxide concentration exceeded the set high value, the desulfurization unit automatically started spraying. When the instantaneous sulfur dioxide concentration fell below the set low value, the desulfurization unit automatically stopped spraying. Later observations revealed that there was waste of desulfurizer during certain periods of spraying. To reduce the consumption of desulfurizer and avoid waste while achieving sulfur dioxide concentration control, this method was invented. Summary of the Invention

[0003] The purpose of this invention is to provide a method for controlling the sulfur dioxide content in dry quenching flue gas. By changing the automatic start-stop of the dry quenching desulfurization unit to control based on the current hourly concentration of sulfur dioxide, the consumption of desulfurizing agent is reduced while achieving sulfur dioxide concentration control, thus avoiding waste of desulfurizing agent. This also prevents the sulfur dioxide concentration from exceeding the standard due to delayed detection of blockages in the dry quenching desulfurization unit, reduces the frequency of blockages in the dry quenching desulfurization unit, and effectively solves the aforementioned problems existing in the background art.

[0004] The technical solution of the present invention is: a method for controlling the sulfur dioxide content in dry quenching flue gas, comprising the following steps: Step S1: The instantaneous value of sulfur dioxide concentration measured by the environmental protection instrument at the dust removal outlet of the dry quenching coke environment is introduced to the computer in the central control room, and the current hourly average value of sulfur dioxide is calculated from the introduced instantaneous value of sulfur dioxide concentration. Step S2: During the hourly interval plus 10 minutes, the dry quenching desulfurization unit is not turned on. Step S3: When the current hourly average value of sulfur dioxide is higher than the set value, the dry quenching desulfurization unit will automatically start. Step S4: When the current hourly average value of sulfur dioxide is lower than the set value, the dry quenching desulfurization unit will automatically shut down. Step S5: After the dry quenching desulfurization device is automatically turned on for a certain period of time, the dry quenching desulfurization device is automatically turned off. Step S6: Set the automatic control and manual control switching program; Step S7: Set the alarm value for the hourly concentration of sulfur dioxide. When the current hourly average concentration of sulfur dioxide is higher than the alarm value, the system will issue an audible and visual alarm.

[0005] In step S3, the set value is set according to the requirements of environmental protection policies, and the operation interface of the dry quenching desulfurization device is provided with a set value setting box.

[0006] In step S5, the automatic start-up time of the dry quenching desulfurization device is matched with the control of sulfur dioxide concentration. The time is set to 3 minutes, and the operation interface of the dry quenching desulfurization device has a manual time setting box.

[0007] In step S6, under automatic control, the dry quenching desulfurization device automatically starts and stops according to the values ​​set in the program; under manual control, the dry quenching desulfurization device will not start automatically and must be started manually by the operator.

[0008] In step S7, the alarm value is set to 50 mg / m³. 3 At this time, the alarm value is set by the program and can be changed by the operator through the operation interface.

[0009] When the dry quenching desulfurization unit starts automatically each time, the Roots blower is started and rotated for 30 seconds before the feed valve is started; when the dry quenching desulfurization unit stops automatically each time, the feed valve is stopped first and the Roots blower is stopped 30 seconds later.

[0010] The beneficial effects of this invention are: by changing the automatic start and stop of the dry quenching desulfurization device to be controlled by the current hourly concentration of sulfur dioxide, the consumption of desulfurizing agent is reduced while achieving sulfur dioxide concentration control, thus avoiding waste of desulfurizing agent, preventing the sulfur dioxide concentration from exceeding the standard due to untimely detection of blockage in the dry quenching desulfurization device, and reducing the number of blockages in the dry quenching desulfurization device. Attached Figure Description

[0011] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention; Figure 3 This is a flowchart of the high hourly sulfur dioxide concentration alarm procedure of the present invention; Figure 4 This is a program interface diagram of an actual implementation of the present invention; In the diagram: 1. Manual control button for feed valve; 2. Feed pipe; 3. Manual control button for Roots blower; 4. Desulfurization silo level display; 5. Automatic / manual selection button; 6. Hourly no-spray time setting box; 7. Automatic desulfurization spray shut-off time setting box; 8. Current hourly SO2 concentration alarm value setting box; 9. System high value setting box; 10. System low value setting box; 11. Format valve frequency preset value setting box; 12. SO2 instantaneous value display; 13. Current hourly average SO2 display; 14. Previous hourly average SO2 display. Detailed Implementation

[0012] To make the purpose, technical solutions, and advantages of the invention's embodiments clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only a small part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0013] A method for controlling the sulfur dioxide content in dry quenching flue gas includes the following steps: Step S1: The instantaneous value of sulfur dioxide concentration measured by the environmental protection instrument at the dust removal outlet of the dry quenching coke environment is introduced to the computer in the central control room, and the current hourly average value of sulfur dioxide is calculated from the introduced instantaneous value of sulfur dioxide concentration. Step S2: During the hourly interval plus 10 minutes, the dry quenching desulfurization unit is not turned on. Step S3: When the current hourly average value of sulfur dioxide is higher than the set value, the dry quenching desulfurization unit will automatically start. Step S4: When the current hourly average value of sulfur dioxide is lower than the set value, the dry quenching desulfurization unit will automatically shut down. Step S5: After the dry quenching desulfurization device is automatically turned on for a certain period of time, the dry quenching desulfurization device is automatically turned off. Step S6: Set the automatic control and manual control switching program; Step S7: Set the alarm value for the hourly concentration of sulfur dioxide. When the current hourly average concentration of sulfur dioxide is higher than the alarm value, the system will issue an audible and visual alarm.

[0014] In step S3, the set value is set according to the requirements of environmental protection policies, and the operation interface of the dry quenching desulfurization device is provided with a set value setting box.

[0015] In step S5, the automatic start-up time of the dry quenching desulfurization device is matched with the control of sulfur dioxide concentration. The time is set to 3 minutes, and the operation interface of the dry quenching desulfurization device has a manual time setting box.

[0016] In step S6, under automatic control, the dry quenching desulfurization device automatically starts and stops according to the values ​​set in the program; under manual control, the dry quenching desulfurization device will not start automatically and must be started manually by the operator.

[0017] In step S7, the alarm value is set to 50 mg / m³. 3 At this time, the alarm value is set by the program and can be changed by the operator through the operation interface.

[0018] When the dry quenching desulfurization unit starts automatically each time, the Roots blower is started and rotated for 30 seconds before the feed valve is started; when the dry quenching desulfurization unit stops automatically each time, the feed valve is stopped first and the Roots blower is stopped 30 seconds later.

[0019] In practical applications, under national environmental protection regulations, the sampling and monitoring point for sulfur dioxide in dry quenching flue gas is located in the middle of the outlet chimney of the dry quenching environmental dust removal system.

[0020] The sulfur dioxide content in dry quenching flue gas has its own unique characteristics. The sulfur dioxide in the dry quenching flue gas originates from the loaded red-hot coke. There are two pathways for the dry quenching flue gas to enter the dry quenching environment dust collection: the first pathway is that the flue gas escaping during the coke loading process is sucked into the dry quenching environment dust collection by the dust collection hood of the dry quenching loading device; the second pathway is that the sulfur dioxide contained in the coke loaded into the dry quenching furnace enters the dry quenching circulating gas, and this gas enters the dry quenching environment dust collection through the discharge port of the pre-storage chamber pressure regulating valve.

[0021] These two pathways determine the significant fluctuations in sulfur dioxide concentration in dry quenching flue gas. The sulfur dioxide concentration in the dry quenching flue gas reaches its peak during coke loading, and then gradually decreases after coke loading until it begins to rise again and reach its peak during the next coke loading.

[0022] In actual production, this invention directly introduces the sulfur dioxide flue gas from the second pathway described above into a dedicated desulfurization unit shared with the coke oven, while a separate dry quenching desulfurization unit is specifically designed to treat the sulfur dioxide flue gas from the first pathway. This invention can also be applied to desulfurization facilities where flue gas from both pathways is introduced into the dry quenching environment for dust removal.

[0023] National environmental protection policies control sulfur dioxide at hourly concentration levels, with 24-hour real-time monitoring. This invention changes the automatic start-up and shutdown of the dry quenching desulfurization unit to be controlled based on the current hourly sulfur dioxide concentration. The dry quenching desulfurization unit uses a program-controlled automatic start-up, shutdown, and chemical spraying mechanism. When the current hourly sulfur dioxide concentration is higher than the set value, the desulfurization unit's feed valve opens, automatically injecting a high-efficiency calcium-based desulfurizing agent into the dust-collecting flue gas of the dry quenching environment. When the current hourly sulfur dioxide concentration is lower than the set value, the desulfurization unit automatically stops spraying. Furthermore, the fluctuation in sulfur dioxide content in the dry quenching flue gas is caused by coke loading. After the coke loading process, the sulfur dioxide content in the flue gas rapidly reaches its peak and then gradually decreases. Therefore, the opening time of the desulfurization unit's feed valve is set to 3 minutes. Three minutes is sufficient to control the peak sulfur dioxide concentration caused by coke loading, after which the sulfur dioxide concentration gradually decreases, and the hourly average sulfur dioxide concentration also gradually decreases. Meanwhile, during the operation of the dry quenching desulfurization unit, it was found that the high hourly sulfur dioxide concentration caused by the furnace loading in the first 10 minutes of each hour did not have a decisive impact on the concentration value for the rest of the hour. Therefore, this invention sets the dry quenching desulfurization unit to not spray chemicals during the first ten minutes of each hour. These measures, being fully automated, significantly reduce the workload of monitoring personnel and prevent the desulfurization unit from failing to start in time when the sulfur dioxide concentration is too high due to human negligence.

[0024] Meanwhile, during use, it was discovered that the high-efficiency calcium-based desulfurizer is a powder that readily absorbs water. In high humidity conditions, the desulfurizer easily cakings, causing blockages in the feed valve of the desulfurization unit and preventing normal feed supply. When a blockage occurs in the feed device, even if the desulfurization unit automatically starts, the hourly sulfur dioxide concentration will not decrease. If this is not detected in time, sulfur dioxide concentrations will exceed the standard. To avoid this, an alarm value for the current hourly sulfur dioxide concentration has been set. Whenever the current hourly sulfur dioxide concentration exceeds this value, the system will sound an alarm to alert monitoring personnel to take emergency measures.

[0025] The dry quenching desulfurization unit uses compressed air generated by a Roots blower to blow the desulfurizing agent discharged from the feed valve into the environmental dust removal pipeline. To prevent the desulfurizing agent remaining in the feed pipeline from caking, the unit is designed to start the Roots blower for 30 seconds before starting the feed valve each time the desulfurization unit is automatically started. Conversely, the unit stops the feed valve for 30 seconds before stopping the Roots blower. This design prevents the desulfurizing agent remaining in the feed pipeline from caking and clogging the environmental dust removal pipeline if it is not promptly injected into the pipeline when the feed valve stops. Example

[0026] The specific steps of this invention are as follows: 1. The instantaneous value of sulfur dioxide concentration measured by the environmental protection instrument at the dust removal outlet of the dry quenching coke oven is transmitted to a dedicated computer in the central control room.

[0027] 2. Based on the calculation function provided by the national environmental protection department, the current hourly average value of sulfur dioxide is calculated from the instantaneous value of the sulfur dioxide concentration and displayed in the dedicated interface of the central control computer.

[0028] 3. The dry quenching desulfurization unit will not be turned on during the period 10 minutes before the hour. This time is set by the program and can be changed by the operator through the operation interface.

[0029] 4. When the current hourly average sulfur dioxide level exceeds a certain set value, the dry quenching desulfurization unit will automatically start. A dedicated setting box for this value is provided on the dry quenching desulfurization unit's operating interface, allowing operators to modify the setting at any time, facilitating timely adjustments based on environmental policy requirements.

[0030] 5. When the current hourly average sulfur dioxide level falls below a certain set value, the dry quenching desulfurization unit will automatically shut down. A dedicated setting box for this value is provided on the dry quenching desulfurization unit's operating interface, allowing operators to modify the setting at any time, facilitating timely adjustments based on environmental policy requirements.

[0031] 6. The dry quenching desulfurization unit will automatically shut down after 3 minutes of automatic operation. This time is programmed and can be manually adjusted by the operator through the interface. The operator can manually change the time duration according to the sulfur dioxide concentration control situation.

[0032] 7. The dry quenching desulfurization unit can switch between automatic and manual control. In automatic control mode, the dry quenching desulfurization unit automatically starts and stops according to the values ​​set in the program. In manual mode, the dry quenching desulfurization unit will not start automatically and must be started manually by the operator.

[0033] 8. Under any circumstances, when the current hourly average concentration of sulfur dioxide is higher than 50 mg / m³ 3 When this occurs, the system will issue an audible and visual alarm. This alarm value is set by the program and can be changed by the operator through the user interface.

[0034] 9. When the dry quenching desulfurization unit starts automatically each time, start the Roots blower and run it for 30 seconds before starting the feed valve. When the dry quenching desulfurization unit stops automatically each time, stop the feed valve first and then stop the Roots blower 30 seconds later.

[0035] Through the above methods and measures, the present invention effectively achieves the following objectives: 1. Control the hourly concentration of sulfur dioxide in dry quenching flue gas to 50 mg / m³. 3 the following.

[0036] 2. The amount of desulfurizing agent used in the dry quenching desulfurization unit has been reduced.

[0037] 3. It avoids the situation where personnel fail to detect blockages in the dry quenching desulfurization unit in time, resulting in excessive sulfur dioxide concentrations.

[0038] 4. Reduced the number of times the dry quenching desulfurization unit was blocked.

[0039] Matters not covered in this invention are common knowledge.

[0040] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for controlling the sulfur dioxide content in dry quenching flue gas, characterized in that... Includes the following steps: Step S1: The instantaneous value of sulfur dioxide concentration measured by the environmental protection instrument at the dust removal outlet of the dry quenching coke environment is introduced to the computer in the central control room, and the current hourly average value of sulfur dioxide is calculated from the introduced instantaneous value of sulfur dioxide concentration. Step S2: During the hourly interval plus 10 minutes, the dry quenching desulfurization unit is not turned on. Step S3: When the current hourly average value of sulfur dioxide is higher than the set value, the dry quenching desulfurization unit will automatically start. Step S4: When the current hourly average value of sulfur dioxide is lower than the set value, the dry quenching desulfurization unit will automatically shut down. Step S5: After the dry quenching desulfurization device is automatically turned on for a certain period of time, the dry quenching desulfurization device is automatically turned off. Step S6: Set the automatic control and manual control switching program; Step S7: Set the alarm value for the hourly concentration of sulfur dioxide. When the current hourly average concentration of sulfur dioxide is higher than the alarm value, the system will issue an audible and visual alarm.

2. The method for controlling the sulfur dioxide content in dry quenching flue gas according to claim 1, characterized in that: In step S3, the set value is set according to the requirements of environmental protection policies, and the operation interface of the dry quenching desulfurization device is provided with a set value setting box.

3. The method for controlling the sulfur dioxide content in dry quenching flue gas according to claim 1, characterized in that: In step S5, the automatic start-up time of the dry quenching desulfurization device is matched with the control of sulfur dioxide concentration. The time is set to 3 minutes, and the operation interface of the dry quenching desulfurization device has a manual time setting box.

4. The method for controlling the sulfur dioxide content in dry quenching flue gas according to claim 1, characterized in that: In step S6, under automatic control, the dry quenching desulfurization device automatically starts and stops according to the values ​​set in the program; under manual control, the dry quenching desulfurization device will not start automatically and must be started manually by the operator.

5. The method for controlling the sulfur dioxide content in dry quenching flue gas according to claim 1, characterized in that: In step S7, the alarm value is set to 50 mg / m³. 3 At this time, the alarm value is set by the program and can be changed by the operator through the operation interface.

6. The method for controlling the sulfur dioxide content in dry quenching flue gas according to claim 1, characterized in that: When the dry quenching desulfurization unit starts automatically each time, the Roots blower is started and rotated for 30 seconds before the feed valve is started; when the dry quenching desulfurization unit stops automatically each time, the feed valve is stopped first and the Roots blower is stopped 30 seconds later.

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