Control method of coke calcium-based desulfurization system for coke-charging dust-removal flue gas of dry quenching furnace

Abstract

The invention discloses a control method of a calcium-based desulfurization system for coke charging dedusting flue gas of a dry quenching furnace, and belongs to the technical field of coking flue gas purification. The method comprises the following steps: monitoring the flue gas sulfur dioxide concentration in real time, and starting a calcium spraying system in an interlocking manner when a threshold value is reached; by controlling the calcium spraying time, the arrival time (T2) of the desulfurizing agent is smaller than or equal to the flowing time (T1) of the flue gas from the monitoring point to the spraying point, so that accurate and synchronous mixing is realized; according to the real-time flue gas flow and SO2 concentration, the calcium spraying amount is dynamically controlled in an interlocking mode, and the calcium-sulfur ratio is maintained to be 1.8-2.4; intelligent ash removal control based on single-bin or total pressure difference triggering is adopted for the bag type dust collector, and ash removal is executed by staggering coke charging operation time periods of the dry quenching furnace according to set intervals. According to the invention, through cooperative intelligent control of time sequence, dosage and ash removal, the problems of desulfurization agent waste, excessive emission and unstable system operation under the intermittent fluctuation flue gas working condition of dry quenching are solved, and efficient desulfurization, resource saving and reliable system operation are realized.

Description

Technical Field

[0001] This invention relates to the field of flue gas purification technology in the coking industry, and in particular to a calcium-based dry desulfurization system control method for intermittent fluctuating flue gas in dry quenching processes. Background Technology

[0002] Dry quenching is a crucial step in coking production. During the coking process, the contact between the red-hot coke and the circulating inert gas generates a large amount of flue gas containing dust and sulfur dioxide (SO2). This flue gas exhibits significant intermittent and fluctuating characteristics: the SO2 concentration rises instantaneously during coking (reaching 50-250 mg / m³). 3 (And possibly even higher), while the concentration is extremely low during non-coke loading periods. To meet increasingly stringent ultra-low emission standards (such as the national ultra-low emission standard requiring a SO2 concentration limit of 50 mg / m³ for dry quenching coke loading dust removal flue gas), 3 Calcium-based dry desulfurization technology is widely used due to its advantages such as simple process and no wastewater discharge.

[0003] However, existing desulfurization systems have significant shortcomings in their control strategies to address the intermittent fluctuations in flue gas from dry quenching furnaces. For example, some publicly available technical solutions include: 1. Inefficient calcium injection control: The addition of desulfurizing agents often relies on timed or simple threshold control, which cannot accurately match the instantaneous changes in flue gas SO2 concentration. This often results in the desulfurizing agent not being added or being insufficient when high concentration flue gas arrives, causing instantaneous emissions to exceed standards; or calcium injection continues even at low concentrations, leading to a large waste of desulfurizing agent and increased operating costs.

[0004] 2. Inappropriate dust removal strategy: Baghouse dust collectors generally use a fixed cycle for dust removal, which is not related to the actual dust accumulation state (pressure difference) of the filter bags. Frequent ineffective dust removal not only accelerates filter bag damage and shortens service life, but also strips unreacted desulfurizing agent from the filter bag surface, reducing desulfurization efficiency and wasting desulfurizing agent; while untimely dust removal will lead to excessive system resistance, affecting the normal operation of the fan and significantly increasing the energy consumption of the dust removal system.

[0005] 3. Poor system coordination: Operations such as dust removal and calcium spraying are not effectively coordinated with the dry quenching process itself (such as the coke charging cycle and the state of the furnace cover). When the dry quenching furnace cover is open for coke charging, the dust removal fan is running at high speed and the system load is high. Dust removal is carried out when the dust collector inlet and outlet pressure difference is higher, the system resistance is greater, which will increase the system energy consumption and easily affect the stability of the system operation.

[0006] Therefore, developing a desulfurization system control method that can achieve precise response, dynamic optimization, and intelligent coordination is of great significance for ensuring the stable operation of dry quenching systems, reducing material and energy consumption, and ensuring long-term stable emission compliance. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a control method for a coke-based desulfurization system for coke dust removal in dry quenching furnaces. This method solves the problem of efficient utilization and stable compliance of desulfurizing agents under intermittent fluctuating flue gas conditions by coordinating and intelligently controlling the timing of calcium injection, the dosage of calcium injection, and the dust collector cleaning strategy.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for controlling a coke-based desulfurization system for coke dust removal in a dry quenching furnace includes the following steps: S1: Real-time monitoring of sulfur dioxide concentration in the flue gas duct in front of the desulfurizer injection point; S2: When the sulfur dioxide concentration reaches the preset start-up threshold, the calcium injection system is interlocked and started to inject calcium-based desulfurizer into the flue gas; S3: Control the start-up timing of the calcium injection system so that the time T2 from interlock start-up to the desulfurizing agent reaching the injection point is less than or equal to the time T1 when the flue gas flows from the sulfur dioxide monitoring point to the injection point. S4: Based on the real-time monitoring of flue gas flow rate and sulfur dioxide concentration, the injection amount of desulfurizing agent is interlocked to maintain the calcium-sulfur molar ratio within the preset range. S5: Monitor the inlet and outlet pressure difference of each filter compartment of the bag filter and / or the total inlet and outlet pressure difference of the bag filter, and execute one of the following dust removal control modes based on the monitored pressure difference: (a) When the inlet and outlet pressure difference of a single compartment reaches the first preset pressure difference threshold, the backflushing cleaning operation of the compartment is initiated. (b) When the total inlet and outlet pressure difference of the bag filter reaches the third preset pressure difference threshold and continues to exceed the preset time, the back-flushing cleaning operation of each compartment is started in sequence. S6: Control the interval between cleaning operations in each compartment (the time interval between the start of cleaning in this compartment and the start of cleaning in the next compartment) to the second preset time interval, and make the cleaning operation time staggered from the coking period of the dry quenching furnace (calculated by the time the furnace cover is open).

[0009] Furthermore, in step S3, controlling the start-up timing of the calcium spraying system specifically involves making T2 less than or equal to T1, preferably T2 being 0.5-1 seconds less than T1.

[0010] Furthermore, in step S2, the preset activation threshold is when the sulfur dioxide concentration reaches the sulfur dioxide concentration limit in the emission standard to be achieved.

[0011] Furthermore, in step S4, the preset calcium-sulfur molar ratio ranges from 1.8 to 2.4.

[0012] Further, in step S5, the first preset differential pressure threshold and / or the third preset differential pressure threshold are set according to the filtration velocity of the dust collector; wherein, the first preset differential pressure threshold is 500Pa to 800Pa, with a lower value taken when the filtration velocity is low and a higher value taken when the filtration velocity is high; the third preset differential pressure threshold is 900Pa to 1200Pa, with a lower value taken when the filtration velocity is low and a higher value taken when the filtration velocity is high. The filtration velocity is a conventional monitoring or calculation parameter in the art, and is related to the flue gas flow rate and the filtration area.

[0013] Furthermore, in mode (a) of step S5, when monitoring the pressure difference of a single compartment and starting the dust removal process, the dust removal is performed sequentially according to the pressure difference of each compartment from high to low; when the pressure difference of a compartment is lower than the first preset pressure difference threshold, the dust removal of that compartment is skipped.

[0014] Furthermore, in mode (b) of step S5, the preset duration is 1 minute.

[0015] Further, in step S6, the second preset time interval is 8-25 minutes and is consistent with the coking cycle of the dry quenching furnace. The coking cycle of the dry quenching furnace refers to the time period from when the furnace lid is closed after the current batch of coke is loaded to when the furnace lid is closed after the next batch of coke is loaded, or the time period from when the furnace lid is opened to begin coking after the current batch of coke is loaded to when the furnace lid is opened to begin coking after the next batch of coke is loaded; both time periods are of equal length. Specifically, the second preset time interval needs to be precisely matched with the coking cycle, and is typically set to 8-25 minutes.

[0016] Within a single coking cycle, a maximum of one compartment can undergo baghouse backflushing cleaning. Cleaning must begin 1-2 minutes after coking is completed and the furnace lid is closed, and the compartment responsible for cleaning must complete all cleaning operations before the next batch of coke is loaded. In other words, all compartment cleaning operations must be completed within the interval between two coking cycles (i.e., the time between closing the furnace lid after the current batch of coke is loaded and opening the lid to prepare for the next batch of coke). This avoids high-load periods during coking and ensures that the high-sulfur flue gas generated during coking flows through the baghouse before cleaning begins, thereby improving desulfurization efficiency and desulfurizer utilization during high-load periods and reducing sulfur dioxide concentration during those periods.

[0017] Further, in step S2, the calcium-based desulfurizing agent is highly active calcium hydroxide with a specific surface area greater than 40 m². 2 / g, purity (calculated as calcium hydroxide) greater than 85%.

[0018] Furthermore, it also includes step S7: drawing back a portion of the flue gas from the outlet of the bag filter booster fan for the transport and fluidization of the calcium-based desulfurizing agent.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. High and stable desulfurization efficiency: Precise timing control of "T2≤T1" ensures optimal spatial and temporal mixing of the desulfurizing agent and high-concentration SO2 flue gas, significantly improving initial reaction efficiency. Combined with dynamic interlocking calcium injection volume control, it ensures the maintenance of an optimized calcium-sulfur ratio under different loads, thereby guaranteeing stable compliance of SO2 concentration at the system outlet. Simultaneously, avoiding backflushing of the dust collector bags during high-load periods of coking reduces flue gas filtration velocity, prolongs the contact time between sulfur dioxide in the flue gas and the desulfurizing agent on the filter bag surface, and improves desulfurization efficiency.

[0020] 2. Significantly reduced operating costs: Precise calcium spray control avoids waste of desulfurizing agent during low-concentration or SO2-free periods; intelligent dust removal strategies reduce ineffective dust removal frequency and compressed air consumption. These two factors work synergistically to significantly reduce the unit consumption of desulfurizing agent and the overall energy consumption of the system. Simultaneously, a portion of the flue gas from the bag filter's booster fan outlet is diverted back for the transport and fluidization of the calcium-based desulfurizing agent, avoiding the increased energy consumption caused by using compressed air as the desulfurizing agent transport and fluidization gas, which necessitates heating the compressed air with a heater.

[0021] 3. Enhanced System Reliability: The intelligent dust removal strategy based on pressure difference avoids abnormally high resistance caused by excessive dust accumulation in the filter bags, while also preventing damage to the filter bags from over-dust removal, thus extending their lifespan. Simultaneously, the proactive staggering of dust removal operations with the main production process avoids back-blowing of the dust collector bags during coke loading, increasing the effective filtration area under high load conditions, reducing filtration velocity, and ultimately lowering the dust collector's operating resistance. This reduces energy consumption during dust removal system operation and improves dust control during coke loading, as well as the overall stability and reliability of the dry quenching unit. Furthermore, a portion of the flue gas from the baghouse dust collector's booster fan outlet is diverted back for the transport and fluidization of the calcium-based desulfurizing agent. Compared to compressed air, this flue gas has a higher temperature and lower humidity, avoiding the caking problems associated with using compressed air as the desulfurizing agent transport and fluidization gas, thereby improving system stability.

[0022] 4. High degree of automation: The entire control process is based on real-time monitoring data and interlocking logic, realizing fully automatic optimized operation of the system, reducing the intensity of manual operation and the risk of misoperation. Attached Figure Description

[0023] Figure 1 This is a flowchart of the control method of the present invention.

[0024] Figure 2 This is a schematic diagram of the calcium injection timing control of the present invention, which shows the spatiotemporal relationship between flue gas flow time T1 and desulfurizer delivery time T2.

[0025] Figure 3 This is a schematic diagram of the structure of the dry quenching coke calcium-based dry desulfurization system to which this invention applies.

[0026] In the diagram: 1-Desulfurization reaction flue, 2-First online monitoring instrument, 3-Injection point, 4-Bag filter, 5-Booster fan, 6-Chimney, 7-Second online monitoring instrument, 31-Desulfurizing agent storage silo, 311-Desulfurizing agent, 32-Weighing module, 33-Gas-material mixing and feeding device, 34-Electric valve, 35-Gas conveying pipe. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of the present invention in any way.

[0028] like Figure 1 As shown, this embodiment provides a control method for a coke-based desulfurization system for coke dust removal in a dry quenching furnace, comprising the following steps: Step S1: Real-time monitoring of sulfur dioxide concentration in flue gas. A high-response online sulfur dioxide analyzer (i.e., the first online monitor 2) is installed in the flue upstream of the desulfurizer injection point to continuously monitor the raw flue gas generated during the dry quenching and coking process in real time.

[0029] Step S2: Calcium spraying system interlock start-up. Preset SO2 concentration start-up threshold (e.g., 50 mg / m³). 3 When the detected SO2 concentration reaches or exceeds the threshold, the control system immediately issues an interlock command to start the feeding and conveying device of the calcium injection system and begin injecting calcium-based desulfurizer into the flue.

[0030] Step S3: Precise control of calcium spraying timing. For example... Figure 2 As shown, the time T1 required for flue gas to flow from the SO2 monitoring point (the installation location of the first online monitor 2) to the desulfurizing agent injection point 3 is accurately measured or calculated. Simultaneously, the time T2 required from the issuance of the interlock start command to the arrival of the desulfurizing agent at the spray nozzle outlet via the delivery system is also determined. Through control logic settings, it is ensured that T2 ≤ T1, preferably controlled to be 0.5-1 seconds less than T1. This aims to ensure that the desulfurizing agent and the monitored high-concentration SO2 flue gas cloud arrive at the mixing point precisely and synchronously or slightly ahead of time, ensuring sufficient contact and reaction between the two, maximizing initial desulfurization efficiency, and avoiding waste caused by injecting desulfurizing agent into a "blank" flue gas section.

[0031] Step S4: Dynamic Interlock Control of Calcium Injection Rate. The system synchronously monitors the flue gas flow rate (Q) and SO2 concentration (C) in real time. The mass flow rate of SO2 in the flue gas is calculated according to the formula M_SO2=Q×C. The feed rate of the calcium injection system is dynamically interlocked with M_SO2, and the injection rate of the desulfurizing agent (based on available calcium) is calculated and adjusted in real time according to the preset target calcium-sulfur molar ratio (Ca / S, ranging from 1.8 to 2.4). If the flue gas flow rate is relatively constant during the coking period, the calcium injection rate can be mainly interlocked with the SO2 concentration. This step ensures that the amount of desulfurizing agent used is always matched with the pollutant load.

[0032] Step S5: Intelligent dust removal control for baghouse dust collectors. This step provides two optional optimized dust removal control modes: Mode (a) (Precise Differential Pressure Control in a Single Compartment): A reliable differential pressure transmitter is installed in each filter compartment of the bag filter. When the inlet and outlet differential pressure of any compartment reaches a first preset differential pressure threshold (set range 500Pa to 800Pa), the cleaning procedure for that compartment is triggered. The cleaning sequence is preferably performed in descending order of real-time differential pressure in each compartment. If the differential pressure of a compartment is lower than the threshold, its cleaning operation is skipped, achieving "on-demand cleaning" and avoiding the negative impact of ineffective cleaning on the filter bags and desulfurization efficiency.

[0033] Mode (b) (Total Differential Pressure Standby / Simplified Control): This mode can be activated when each compartment does not have an individual differential pressure detection device or the detection device is unstable. It monitors the overall inlet and outlet differential pressure of the bag filter. When the total differential pressure reaches the third preset differential pressure threshold (set range 900Pa to 1200Pa), and this state persists for more than a preset time (e.g., 1 minute, to exclude instantaneous fluctuations), the control system determines that the overall filtration resistance is too high and immediately starts the backflushing procedure, sequentially performing one cleaning cycle on each compartment.

[0034] The specific values ​​of the first and third preset differential pressure thresholds are both related to the filtration velocity during dust collector operation: lower values ​​are used when the filtration velocity is low, and higher values ​​are used when the filtration velocity is high. The filtration velocity can be calculated based on the real-time flue gas flow rate and the known filter area, and is a conventional parameter in this field.

[0035] Step S6: Coordinated scheduling of ash removal operations. To prevent continuous impact on the system from ash removal operations and to ensure the continuity of desulfurization effect, a second preset time interval (e.g., 8 to 25 minutes) is controlled between the start-up of ash removal in each compartment. This interval is preferably consistent with the coking cycle of the dry quenching furnace (i.e., the time from when the furnace lid is closed after the coke in this furnace is loaded to when the furnace lid is closed after the coke in the next furnace is loaded). Bag backflushing ash removal should begin 1-2 minutes after the coke is loaded and the furnace lid is closed. The ash removal operation in the compartment is required to be completed before the coke in the next furnace starts loading.

[0036] More importantly, the control system obtains the coking operation plan through communication with the dry quenching coke main control system, and actively schedules the ash removal operation to the coking interval period, strictly avoiding the coking period (measured by the furnace cover opening time, during which the dust removal fan will run at high speed), thereby improving the desulfurization efficiency during the high load period of coking and ensuring the stable operating pressure of the desulfurization system, without affecting the main production.

[0037] Furthermore, the calcium-based desulfurizing agent is preferably highly active calcium hydroxide with a specific surface area greater than 40 m². 2 / g, purity (calculated as calcium hydroxide) greater than 85% to ensure its rapid and efficient reactivity with SO2.

[0038] Furthermore, the process includes step S7: drawing back a portion of the clean flue gas from the outlet of the bag filter booster fan 5 as the gas source for the desulfurizing agent pneumatic conveying system and the fluidization of the silo pump. Utilizing the dry, high-temperature, and stable characteristics of this portion of flue gas, it can effectively prevent the desulfurizing agent from absorbing moisture and caking during the conveying process, ensuring the stable and smooth operation of the conveying system.

[0039] Working principle of the invention: Combination Figure 3 The system structure shown below works on the following principle: I. Desulfurizing agent transportation process 1. Storage and metering: Desulfurizing agent 311 is stored in desulfurizing agent storage silo 31. The bottom outlet of the storage silo is connected to a weighing module 32 with a frequency conversion unloading device for accurate metering of the amount of desulfurizing agent discharged.

[0040] 2. Gas-material mixing: The weighed desulfurizing agent enters the gas-material mixing feeder 33, and at the same time, the gas conveying pipe 35 is also connected to the device to introduce gas (as described in step S7, the flue gas is drawn back) into it, so that the desulfurizing agent and the gas are mixed to form a conveyable gas-material flow.

[0041] 3. Injection into the flue: The discharge port of the gas-material mixing and feeding device 33 controls the flow rate through the electric valve 34 and is finally connected to the injection point 3 on the desulfurization reaction flue 1 to inject the desulfurizing agent into the flue to participate in the reaction.

[0042] II. Flue Gas Treatment and Emission Process 1. Initial Monitoring and Reaction: The flue gas to be treated enters the desulfurization reaction flue duct 1. Before injection point 3, a first online monitoring instrument 2 is installed on the flue duct to monitor parameters such as the SO2 concentration of the raw flue gas. After the desulfurizing agent is injected from injection point 3, it undergoes a desulfurization reaction with the flue gas in the flue duct.

[0043] 2. Dust removal and pressurization: The flue gas that has completed the initial reaction enters the bag filter 4 to remove reaction products and dust; the purified flue gas then enters the booster fan 5 to increase the flue gas pressure to meet emission requirements.

[0044] 3. Emission and Monitoring: The pressurized flue gas is sent to the chimney 6 for emission. A second on-line monitor 7 is installed on the chimney to monitor various indicators of the finally emitted flue gas and ensure达标排放.

[0045] Specific embodiments are provided below. The provided embodiments can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way.

[0046] Embodiment 1 This embodiment demonstrates the system operation in mode (a) (precision control of differential pressure in a single bin).

[0047] 1. System and Parameter Preset: The bag filter 4 has a total of 8 chambers, and each chamber is equipped with a differential pressure transmitter. The filtration velocity is 0.78 m / s. Preset in the control system: SO2 start threshold = 50 mg / m 3 (According to the national ultra-low emission standard requirements, the SO2 concentration limit for the flue gas emission from the coke charging dust removal of the dry quenching coke is 50 mg / m 3 ); Target Ca / S ratio = 2.0; T1 (measured) = 3.0 s; Controlled T2 = 2.5 s (0.5 s smaller than T1); First preset differential pressure threshold = 700 Pa; Interval time for cleaning operation = 10 minutes (consistent with the coke charging cycle of the dry quenching coke oven); The cleaning operation strictly avoids the coke charging period (counting from the furnace cover opening signal).

[0048] 2. Desulfurization Agent: High-activity calcium hydroxide is used, with a specific surface area of 42 m 2 / g and a purity (calcium hydroxide content) of 90%.

[0049] 3. Operation Process: Steps S1 - S4: When coke charging starts, the SO2 concentration rapidly rises to 150 mg / m 3 . The signal of the first on-line monitor 2 is triggered, and the calcium injection system is immediately started. Since T2 (2.5 s) < T1 (3.0 s), the desulfurization agent "waits" at the injection point 3 for about 0.5 s for the arrival of the high-concentration flue gas. The control system dynamically adjusts the rotational speed of the feeder according to the real-time flue gas flow rate (about 180,000 m 3 / h) and the SO2 concentration, and controls the desulfurization agent dosage at the level of Ca / S = 2.0.

[0050] Step S5: After running for a period of time, the differential pressure of chamber #3 first rises to 720 Pa and lasts for more than 1 minute, triggering its cleaning program. After the cleaning of chamber #3, the differential pressure drops to about 400 Pa. After an interval of 10 minutes, the differential pressure of chamber #5 reaches 780 Pa and lasts for more than 1 minute, triggering cleaning. The differential pressures of the remaining chambers are all between 500 - 600 Pa, lower than the threshold, and no cleaning is performed.

[0051] Step S6: All dust removal commands are executed after the control system confirms that the current period is not a coking period.

[0052] Step S7: The clean flue gas at approximately 51°C after the booster fan 5 is partially drawn back for pneumatic conveying and fluidization of the desulfurizing agent.

[0053] 4. Operational Results: The SO2 concentration at the system outlet remained stable at 15 mg / m³. 3 The desulfurization efficiency reached over 90%, and the consumption of desulfurizing agent was in high agreement with the theoretical calculation value, achieving efficient, stable and economical operation.

[0054] Example 2 This embodiment demonstrates operation in mode (b) (total differential pressure control) and under different differential pressure thresholds.

[0055] 1. System and Parameter Presets: Enable total differential pressure control mode. Presets: Third preset differential pressure threshold = 1200Pa; duration = 1 minute; ash cleaning interval = approximately 10 minutes (consistent with the coking cycle of a dry quenching coke oven). Other basic parameters are the same as in Example 1.

[0056] 2. Operation Process: During system operation, the total differential pressure of bag filter 4 slowly rises and stabilizes at 1250 Pa for more than 1 minute. The control system determines that the dust removal condition is triggered and starts the backflushing program. Dust removal is performed on one compartment approximately every 10 minutes, following the sequence #1→#2→...→#8. During the dust removal process, the total differential pressure gradually decreases. When the total differential pressure drops below 950 Pa, the current dust removal cycle is completed and automatically stops. A new cycle begins when the total differential pressure meets the trigger condition again. The dust removal period strictly avoids coke charging operations (based on the furnace cover opening signal).

[0057] 3. Operational Results: The SO2 concentration at the system outlet remained stable at 16 mg / m³. 3 The desulfurization efficiency is approximately 89%. Although the control precision is slightly lower than that of mode (a) in Example 1, it can still effectively ensure compliance with emission standards and demonstrates the practicality and robustness of the method of the present invention under conditions where detection devices are limited.

[0058] Comparative Example 1 To highlight the advantages of the dust removal strategy of this invention, a comparative example of excessively frequent dust removal is provided.

[0059] 1. Control parameters: Mode (a) is used, but the first preset differential pressure threshold is set to a low 400 Pa, and the chamber cleaning interval is shortened to 1 minute. Other conditions are the same as in Example 1.

[0060] 2. Operational Results: Due to the excessively low differential pressure threshold, each compartment frequently entered the dust removal state. A large amount of the desulfurizing agent that had just accumulated on the filter bag surface and had not yet fully reacted was blown off, severely weakening the continuous deep desulfurization effect of the filter bag layer. Ultimately, the SO2 concentration at the system outlet rose to 59 mg / m³. 3 The desulfurization efficiency was only 60.7%. Although the Ca / S ratio remained at 2.0, the desulfurization effect deteriorated significantly.

[0061] 3. Conclusion: This comparative example fully demonstrates that "on-demand cleaning based on a reasonable differential pressure threshold" and "maintaining a reasonable cleaning interval" are crucial for maintaining the desulfurization function of the bag filter and ensuring the overall desulfurization efficiency, and are one of the key innovations of this invention.

[0062] Comparative Example 2 To highlight the economic advantages of the "dynamic interlocking control of calcium spraying volume" technology in this invention, a comparative example with a fixed calcium spraying volume that does not change with SO2 load is set up.

[0063] 1. Control Parameters: Except for the calcium injection control method, all other conditions are exactly the same as in Example 1. In this comparative example, the interlock between the calcium injection amount and the flue gas SO2 concentration and flow rate is removed, and the rotational speed of the desulfurizing agent feeder is set to a fixed value. This fixed value is based on the possibility of higher SO2 concentrations (e.g., 150 mg / m³). 3 Configure settings to ensure compliance even under the most unfavorable operating conditions.

[0064] 2. Operational Results: During the initial coking stage when SO2 concentration was low, the actual calcium-to-sulfur ratio (Ca / S) was significantly higher than the required value due to the fixed calcium injection rate. Although the system outlet SO2 concentration could be maintained at a low level (approximately 13 mg / m³),… 3 The low concentration is due to the large amount of desulfurizing agent sprayed, resulting in a large amount of unreacted desulfurizing agent on the filter bag. The desulfurization efficiency is about 91%, but according to calculations, the average calcium-sulfur ratio during the entire coking cycle is as high as 4 or more.

[0065] 3. Conclusion: This comparative example shows that, with desulfurization efficiency essentially equivalent to Example 1 (Ca / S=2.0), the traditional control method using a fixed calcium injection rate results in at least 100% higher desulfurizer consumption compared to the dynamic interlocking control method of this invention. This clearly demonstrates the outstanding effect of step S4 of this invention in avoiding desulfurizer waste and significantly reducing operating costs. Only through real-time interlocking control can precise matching of desulfurizer dosage and pollutant load be achieved, thus optimizing economic and environmental benefits.

[0066] The above embodiments and comparative examples together demonstrate that the control method for the calcium-based desulfurization system of coke dust removal in dry quenching furnaces provided by the present invention can effectively adapt to the intermittent fluctuations of dry quenching flue gas. Through precise control of calcium injection timing, dynamic calcium injection quantity interlocking, and intelligent ash removal management coordination, the material consumption and operating costs are significantly reduced while ensuring stable sulfur dioxide emissions meet standards. At the same time, the automation level and long-term reliability of the system operation are improved.

[0067] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be within the scope of protection of the present invention.

Claims

1. A control method for a coke-based desulfurization system for coke dust removal in a dry quenching furnace, characterized in that, Includes the following steps: S1: Real-time monitoring of sulfur dioxide concentration in the flue gas duct in front of the desulfurizer injection point; S2: When the sulfur dioxide concentration reaches the preset start-up threshold, the calcium injection system is interlocked and started to inject calcium-based desulfurizer into the flue gas; S3: Control the start-up timing of the calcium injection system so that the time T2 from interlock start-up to the desulfurizing agent reaching the injection point is less than or equal to the time T1 when the flue gas flows from the sulfur dioxide monitoring point to the injection point. S4: Based on the real-time monitoring of flue gas flow rate and sulfur dioxide concentration, the injection amount of desulfurizing agent is interlocked to maintain the calcium-sulfur molar ratio within the preset range. S5: Monitor the inlet and outlet pressure difference of each filter compartment of the bag filter and / or the total inlet and outlet pressure difference of the bag filter, and execute one of the following dust removal control modes based on the monitored pressure difference: (a) When the inlet and outlet pressure difference of a single compartment reaches the first preset pressure difference threshold, the backflushing cleaning operation of the compartment is initiated. (b) When the total inlet and outlet pressure difference of the bag filter reaches the third preset pressure difference threshold and continues to exceed the preset time, the back-flushing cleaning operation of each compartment is started in sequence. S6: Control the interval between cleaning operations in each compartment to the second preset time interval, and stagger the cleaning operation time from the coking period of the dry quenching furnace.

2. The control method for the calcium-based desulfurization system of coke oven dust removal system in dry quenching furnace according to claim 1, characterized in that, In step S3, controlling the start-up timing of the calcium spraying system specifically means making T2 less than or equal to T1, preferably T2 is 0.5-1 seconds less than T1.

3. The control method for the calcium-based desulfurization system of coke charging dust removal system in a dry quenching furnace according to claim 1, characterized in that, In step S2, the preset activation threshold is when the sulfur dioxide concentration reaches 50 mg / m³. 3 .

4. The control method for the coke-based desulfurization system of the dry quenching furnace charging coke dust removal flue gas according to claim 1, characterized in that, In step S4, the preset calcium-sulfur molar ratio ranges from 1.8 to 2.

4.

5. The control method for the coke-based desulfurization system of the dry quenching furnace charging coke dust removal flue gas according to claim 1, characterized in that, In step S5, the first preset differential pressure threshold and / or the third preset differential pressure threshold are set according to the filtration velocity of the dust collector; The first preset differential pressure threshold is 500Pa to 800Pa, with a lower value when the filtration velocity is low and a higher value when the filtration velocity is high. The third preset differential pressure threshold is 900Pa to 1200Pa, with a lower value when the filtration velocity is low and a higher value when the filtration velocity is high.

6. The control method for the coke-based desulfurization system of the dry quenching furnace charging coke dust removal flue gas according to claim 1, characterized in that, In mode (a) of step S5, when monitoring the pressure difference of a single compartment and starting the dust removal process, the dust removal is performed sequentially according to the pressure difference of each compartment from high to low; when the pressure difference of a compartment is lower than the first preset pressure difference threshold, the dust removal of that compartment is skipped.

7. The control method for the coke-based desulfurization system of the dry quenching furnace charging coke dust removal flue gas according to claim 1, characterized in that, In mode (b) of step S5, the preset duration is 1 minute.

8. The control method for the coke-based desulfurization system of the dry quenching furnace charging coke dust removal flue gas according to claim 1, characterized in that, In step S6, the cleaning operation of all compartments is completed within the interval between two coke loading operations.

9. The control method for the coke-based desulfurization system of the dry quenching furnace charging coke dust removal flue gas according to claim 1, characterized in that, In step S2, the calcium-based desulfurizing agent is highly active calcium hydroxide with a specific surface area greater than 40 m². 2 / g, purity greater than 85%.

10. The control method for the coke-based desulfurization system of the dry quenching furnace charging coke dust removal flue gas according to claim 1 or 9, characterized in that, It also includes step S7: drawing back a portion of the flue gas from the outlet of the bag filter booster fan for the transport and fluidization of the calcium-based desulfurizing agent.

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