High-altitude mine internal pressurization oxygen supplement circulating ventilation system

Abstract

The application discloses a high-altitude mine internal pressure-increasing oxygen-supplementing circulating ventilation system, relates to the technical field of mine ventilation and oxygen supplementing, and comprises five modules of a main circulating fan, a dirty air purification module, a precise oxygen supplementing module, a controllable fresh air supplementing module and an intelligent monitoring and regulating module. The main circulating fan constructs a stable circulating air path. The dirty air purification module removes dust and harmful gases in depth through a dust removal and adsorption device and a high-efficiency composite absorbent. The precise oxygen supplementing module adopts double molecular sieve adsorption tanks to alternately produce oxygen and directionally distribute oxygen-enriched air. The controllable fresh air module dynamically adjusts the fresh air volume. The intelligent monitoring module collects environment and equipment parameters in real time, and realizes intelligent operation in normal circulation and emergency dilution double modes in linkage. The application realizes the integration of pressure-increasing oxygen supplementing, efficient purification, energy-saving circulation and intelligent regulation, guarantees the health of workers and labor efficiency, reduces energy consumption, and provides reliable support for safe and efficient development of high-altitude mineral resources.

Description

Technical Field

[0001] This invention relates to the technical field of mine ventilation and oxygenation, and more particularly to a pressurized oxygenation and circulating ventilation system for high-altitude mines. Background Technology

[0002] As mineral resource development continues to expand into high-altitude areas, regions above 2,500 meters in altitude, such as the Qinghai-Tibet Plateau and the Yunnan-Guizhou Plateau, have become important development targets, providing crucial support for global mineral resource security. However, the unique low-pressure, low-oxygen environment of high-altitude regions presents severe and urgent technical challenges to safe mine production. Related research data shows that for every 1,000 meters increase in altitude, atmospheric pressure decreases by approximately 11 kPa, and the partial pressure of oxygen decreases accordingly, resulting in an oxygen content in the air of these regions that is only 65%-80% of that at sea level. In this relatively extreme physiologically hypoxic environment, not only does it directly harm the health of underground workers and significantly reduce labor efficiency, but it also places far more stringent requirements on the design and operation of mine ventilation and oxygen supply systems than in conventional low-altitude mining areas.

[0003] Currently, existing technical solutions for ventilation and oxygen supply in high-altitude mines generally suffer from numerous problems: traditional ventilation systems often follow design principles from low-altitude mining areas, making it difficult to adapt to the wind pressure and oxygen partial pressure requirements of high-altitude, low-pressure environments, resulting in low ventilation efficiency and insufficient oxygen supply; some oxygen supplementation solutions adopt a crude oxygen supply model, lacking precise control mechanisms, which not only wastes a large amount of oxygen resources but also makes it difficult to ensure that the oxygen concentration at the working face remains stable within a safe range; at the same time, dust, carbon monoxide (CO), and nitrogen oxides (NOx) generated underground in high-altitude mines... x Harmful gases such as methane (CH4) have limited processing efficiency with traditional purification devices, and the purification process lacks coordination with ventilation and oxygen replenishment systems, easily leading to the accumulation of harmful gases. Furthermore, existing systems mostly operate in a single mode, unable to flexibly adjust their operation according to dynamic changes in underground environmental parameters. Under normal operating conditions, energy consumption is too high, and in emergencies such as excessive levels of harmful gases, rapid response is difficult, further exacerbating safety risks. These problems severely restrict the safe, efficient, and economical development of mineral resources in high-altitude areas.

[0004] Therefore, developing an integrated system that can collaboratively solve core technical challenges in high-altitude mines, such as low pressure and low oxygen, insufficient ventilation and oxygen supply, excessive energy consumption, and high safety risks, has become an urgent need in the current field of high-altitude mining. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a pressurized oxygen supply and circulation ventilation system for high-altitude mines. Through the coordinated operation of five functional modules and dual-mode intelligent operation, it achieves integrated pressurized oxygen supply, efficient purification, energy-saving circulation, and intelligent control, ensuring safe mine production and efficient development of mineral resources.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a high-altitude mine internal pressurization and oxygen replenishment circulation ventilation system, including a main circulation fan module, a waste air purification module, a precise oxygen replenishment module, a controllable fresh air supply module, and an intelligent monitoring and control module; The main circulating fan module is used to establish and maintain stable power for the circulating air path, including a variable frequency main fan, return air shaft, intake air shaft, transport roadway, intake air roadway and return air roadway; the main circulating fan module drives the airflow to flow sequentially through the intake air shaft, the bottom yard, the transport roadway, the intake air roadway, the working face, the return air roadway and the return air shaft through the variable frequency main fan, forming a complete circulating air path, providing the necessary airflow power foundation for sewage purification, fresh air supply and precise oxygen supplementation; The waste air purification module and the controllable fresh air supply module are connected in parallel branches, both connected to the return air treatment front end of the circulating air path driven by the main circulating fan module, to achieve purified airflow circulation and fresh air supply. The controllable fresh air supply module includes a controllable fresh air supply duct for dynamically adjusting the fresh air supply volume. The waste air purification module includes a dust removal and adsorption device, which consists of a cyclone dust collector, a harmful gas adsorption device, and a water tank. The inlet of the harmful gas adsorption device is connected in series with the outlet of the cyclone dust collector. The water tank is located below the cyclone dust collector and is fluidly connected to the sewage discharge channel of the cyclone dust collector. The waste air purification module is used for deep purification of dust and harmful gases in the circulating airflow. The precise oxygen supply module is located in the intake airway, and its output end is connected to the rear end of the circulating air path driven by the main circulating fan module. The precise oxygen supply module includes an oxygen generator and an oxygen delivery pipeline. The oxygen generator includes a controller, an air compressor, a molecular sieve adsorption tank, and an oxygen storage tank. The air compressor, molecular sieve adsorption tank, and oxygen storage tank are fluidly connected in sequence. One end of the oxygen delivery pipeline is connected to the oxygen storage tank, and the other end extends to the oxygen-required area downhole. The intelligent monitoring and control module is used to collect environmental parameters and the operating status of each module, so as to realize the coordinated control of multiple modules.

[0007] Furthermore, the variable frequency main fan operates dynamically according to the instructions of the intelligent monitoring and control module. By adjusting its own speed, it changes the total air volume and air pressure of the circulating air path, ensuring that the airflow can effectively carry and distribute the oxygen-rich air injected by the precise oxygen supply module, while meeting the air volume requirements of the waste air purification module and the controllable fresh air supply module.

[0008] Furthermore, the cyclone dust collector is equipped with a water sprayer, an impeller, a circular guide plate, guide vanes, and a dewatering device, arranged sequentially from the air inlet to the inside of the housing. The water sprayer is installed on the inner wall of the air inlet of the cyclone dust collector and is used to spray water mist containing a high-efficiency composite absorbent. The impeller is located downstream of the water sprayer and is connected to the motor output end of the cyclone dust collector. The circular guide plate is fixed on the side of the impeller away from the water sprayer. The cross-section of the flow channel is reduced along the airflow direction by the circular guide plate, and works with the impeller to generate a high-speed airflow to fully atomize the water droplets, thereby improving the contact efficiency between the water mist and dust and harmful gases. The guide vanes are located downstream of the circular guide plate. When the guide vanes rotate at high speed, they use centrifugal force to throw the water droplets wrapped with dust onto the device wall and guide them into the sewage discharge channel at the bottom of the cyclone dust collector, and finally into the water tank. The dehydration device is fixed on the inner side of the outlet end of the cyclone dust collector and is used to separate residual water droplets from the airflow and output the treated gas to the harmful gas adsorption device.

[0009] Furthermore, the main components of the high-efficiency composite absorbent are an oxidant component, an alkaline absorbent, a catalyst, a complexing agent, and auxiliary additives; the content of each component is expressed as a percentage by mass. The oxidant components are 20-25% potassium permanganate, 3-5% sodium hypochlorite, and 2-5% sodium persulfate; the oxidant is the core active component of this reagent, responsible for oxidizing NO, which is poorly soluble in water, into easily absorbed NO2, and oxidizing CO into CO2; The alkaline absorbent consists of 15-20% sodium hydroxide, 10-15% sodium carbonate, and 5-10% potassium hydroxide. The alkaline absorbent is used to absorb acidic gases and adjust the pH of the solution, providing a suitable acid-base environment for the oxidation reaction. The catalyst consists of 2-4% copper sulfate, 1-3% ferrous sulfate, 1-2% cerium nitrate, and 1-2% manganese dioxide. The catalyst is used to accelerate the redox reaction, reduce the activation energy, and improve the purification efficiency. The complexing agent consists of 5-8% disodium EDTA, 3-5% sodium citrate, and 2-3% triethanolamine. The complexing agent is used to form stable complexes with metal ions, preventing metal ion precipitation and enhancing the selective absorption of harmful gases. The auxiliary additives consist of 0.5-1% sodium benzoate, 0.3-0.8% sodium dodecylbenzenesulfonate, 1-2% sodium silicate, and 0.2-0.5% thiourea. These auxiliary additives are used to improve the performance and storage stability of the high-efficiency composite absorbent in mining environments.

[0010] Furthermore, the preparation steps of the highly efficient composite absorbent are as follows: S1. Solution preparation: Add 60% deionized water to a stirred reactor and heat to 40-50℃. S2. Dissolution of alkaline components: Slowly add sodium hydroxide and sodium carbonate under stirring conditions, and stir until completely dissolved; S3. Addition of oxidant: After the solution cools to below 30°C, slowly add potassium permanganate and continue stirring for 30 minutes; S4. Catalyst dissolution: Dissolve copper sulfate and ferrous sulfate separately in a small amount of deionized water and then slowly add them to the reaction vessel; S5. Adding complexing agent: Add disodium EDTA and sodium citrate, and stir until completely dissolved; S6. Additive addition: Add ethylene glycol, sodium benzoate and sodium dodecylbenzene sulfonate in sequence, and stir until well mixed; S7. Volumetric Filtration: Add deionized water to the specified volume, filter to remove insoluble matter, and obtain the finished product.

[0011] Furthermore, a partition is vertically fixed inside the water tank, dividing the inside of the water tank into a clean water tank and a wastewater tank; The outer wall of the water purification tank is equipped with a water replenishment pipe and a high-efficiency composite absorbent storage box; the outlet end of the water replenishment pipe extends vertically to the upper part of the water purification tank and is fluidly connected to the water purification tank; the high-efficiency composite absorbent storage box is fixed to the outer wall of the water tank, and the outlet end of the high-efficiency composite absorbent storage box is connected to the water purification tank, and the amount added to the water purification tank is adjusted according to the concentration of harmful gases; the bottom of the sewage tank is connected to a drain pipe for discharging sewage.

[0012] Furthermore, the interior of the harmful gas adsorption device is provided with a secondary dehydrator and a harmful gas adsorption plate in sequence along the airflow direction; The secondary dehydrator is fixed at the inlet end of the harmful gas adsorption device and has a built-in high-efficiency hydrophobic membrane component; the inlet of the secondary dehydrator is sealed to the outlet of the dehydration device to remove residual water vapor in the circulating airflow. The harmful gas adsorption plates are arranged in multiple parallel layers along the airflow direction downstream of the secondary dehydrator, adopting a modular multi-layer structure design and being detachably connected to the shell of the harmful gas adsorption device. The interior of the harmful gas adsorption plates is filled with a modified composite adsorbent, which uses high specific surface area activated carbon as the base material and is loaded with copper oxide and zinc oxide active components. The modified composite adsorbent can be recycled through a thermal regeneration process after saturation.

[0013] Furthermore, a controller, an air compressor, two molecular sieve adsorption tanks, and an oxygen storage tank are fixedly installed inside the oxygen generator housing; the controller is electrically connected to the valve assemblies of the air compressor and the molecular sieve adsorption tanks respectively via signal lines; The molecular sieve adsorption tank is filled with high specific surface area modified zeolite molecular sieves, which have a higher adsorption selectivity for nitrogen molecules than for oxygen. Under pressure, nitrogen molecules are adsorbed and locked in the microporous structure by the molecular sieve, while oxygen and argon molecules pass through the adsorption layer and collect in the oxygen storage tank. When one of the molecular sieve adsorption tanks reaches adsorption saturation, the oxygen generator system automatically switches to depressurization desorption mode, releasing pressure to allow nitrogen to desorb and be discharged quickly. At the same time, the other molecular sieve adsorption tank enters pressurized adsorption mode, and oxygen-enriched air is continuously produced through periodic alternation. The outlet of the oxygen storage tank is sealed to one end of the oxygen delivery pipeline, which is used to deliver oxygen-enriched air to the oxygen-required working area.

[0014] Furthermore, the intelligent monitoring and control module includes a main control unit, distributed monitoring sensors, and a signal transmission module. The main control unit is connected to the distributed monitoring sensors and the execution components of each functional module via the signal transmission module. The intelligent monitoring and control module collects core safety parameters through the distributed monitoring sensors, including the concentrations of oxygen, carbon monoxide, carbon dioxide, dust, methane, and nitrogen oxides, as well as atmospheric pressure, temperature, and tunnel wind speed. It also simultaneously receives real-time operating data from each functional module, including the dust removal efficiency of the waste air purification module and the adsorption saturation of the harmful gas adsorption unit; the valve opening, fresh air flow, and fan operating power of the controllable fresh air supply module; the oxygen concentration, oxygen supply, and oxygen generator operating pressure of the precise oxygen supply module; and the variable frequency speed, actual wind pressure, and air volume of the main circulation fan module. The intelligent monitoring and control module supports collaborative linkage with the central monitoring platform, and allows remote viewing and manual intervention of the collaborative status of multiple modules via Web and mobile terminals, with reserved interfaces for intelligent upgrades. The controllable fresh air supply module and the waste air purification module form a parallel branch in the air path connection. When the intelligent monitoring and control module detects that the concentration of harmful gases is within a safe range, the system mainly operates with the waste air purification module, so that the circulating air is treated by the cyclone dust collector and the harmful gas adsorption device and reused. The controllable fresh air supply module only introduces the minimum necessary fresh air volume. When the intelligent monitoring and control module detects that the concentration of any harmful gas exceeds the preset safety threshold, the fresh air supply volume of the controllable fresh air supply module is increased from the minimum necessary air volume to the rated air volume to quickly eliminate the risk of excessive harmful gases. An adjustable damper is configured on the return air side of the roadway. The intelligent monitoring and control module dynamically calculates the optimal wind resistance threshold based on real-time data collected by distributed sensors, and automatically controls the opening of the adjustable damper. By increasing or decreasing the local wind resistance on the return air side, the overall wind pressure of the circulating air path is adjusted. During the process of adjusting resistance and increasing pressure, the intelligent monitoring and control module synchronously sends speed correction commands to the frequency converter of the main circulation fan module, and dynamically optimizes the fan frequency converter parameters according to the change in air resistance. If the concentration of harmful gases fluctuates during the pressure adjustment process, the intelligent monitoring and control module will simultaneously link with the controllable fresh air supply module to adjust the fresh air volume, ensuring the dilution effect of harmful gases while increasing pressure.

[0015] Furthermore, the system is configured with a dual-mode intelligent operation mechanism, which achieves mode switching through real-time data feedback from the intelligent monitoring and control module. The two operation modes are as follows: Normal circulation mode: It is suitable for working conditions where the concentration of harmful gases meets the standard and the oxygen demand is stable. The controllable fresh air supply module operates with the minimum required air volume, the main circulation fan module speed is maintained at 10%-30% of the rated speed, the airflow is reused after being treated by the sewage purification module, the precise oxygen supply module dynamically adjusts the oxygen supply amount according to the oxygen partial pressure data, and the intelligent monitoring and control module realizes on-demand resistance adjustment and pressure increase by adjusting the damper (7). Emergency Dilution Mode: When the intelligent monitoring and control module detects that the concentration of harmful gas in the well exceeds the preset safety threshold, it switches to emergency dilution mode; the controllable fresh air supply module increases the fresh air volume to 120%-150% of the rated air volume, the regulating damper (7) is fully opened, and the speed of the main circulation fan module is increased to 80%-100% of the rated speed, driving the airflow to accelerate the dilution of harmful gas; when the concentration of harmful gas drops below the safety threshold and stabilizes, the system automatically switches back to normal circulation mode.

[0016] The beneficial effects of this invention are: This invention relates to a high-altitude mine internal pressurization and oxygen supply circulation ventilation system, which specifically addresses problems such as low pressure and low oxygen, insufficient ventilation and oxygen supply, accumulation of harmful gases, and excessive energy consumption in high-altitude areas, offering multiple significant benefits. The system utilizes five interconnected modules, combining frequency conversion control of the main circulating fan with dynamic resistance adjustment of the dampers. This, coupled with molecular sieve oxygen generation and directional delivery technology in the precise oxygen supply module, effectively increases the partial pressure of oxygen underground, ensuring stable oxygen concentration at the working face. This protects the health of workers and significantly improves labor efficiency, effectively adapting to extreme environments above 2500 meters in altitude. Regarding air purification, the combination of a high-efficiency composite absorbent and a modified composite adsorbent achieves the purification of dust, CO, and NO. x The system achieves deep removal of harmful gases with high purification efficiency. The water tank's design, separating clean and wastewater, along with the adsorbent's thermal regeneration function, balances purification effectiveness with economic efficiency. The system employs a waste-air circulation and reuse mode, introducing only the minimum necessary fresh air volume under normal operating conditions. Combined with the low-speed operation of the variable frequency fan, energy consumption is significantly reduced. A dual-mode intelligent switching mechanism can quickly activate the emergency dilution mode when harmful gases exceed standards, rapidly eliminating risks by increasing fresh air volume and fan speed, thus balancing energy saving and safety. Furthermore, the intelligent monitoring and control module achieves real-time matching of environmental parameters and equipment status, supporting remote monitoring and manual intervention, providing a reliable guarantee for the safe, efficient, and economical development of high-altitude mineral resources. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall system of the present invention; Figure 2 This is a schematic diagram of a single working surface system of the present invention; Figure 3 This is a schematic diagram of the high-efficiency dust removal and harmful gas adsorption device of the present invention; Figure 4 Schematic diagram of the cross-section of a high-efficiency dust removal and harmful gas adsorption device; Figure 5 This is a schematic diagram of an oxygen concentrator; Figure 6 This is a flowchart of the operation of the system of the present invention.

[0018] In the diagram: 1. Variable frequency main fan; 2. Return air shaft; 3. Dust removal and adsorption device; 31. Cyclone dust collector; 311. Air inlet; 312. Water sprayer; 313. Impeller; 314. Circular guide plate; 315. Guide vane; 316. Dehydration device; 317. Sewage discharge channel; 32. Harmful gas adsorption device; 321. Secondary dehydrator; 322. Harmful gas adsorption plate; 323. Air outlet; 33. Water tank; 331. Clean water tank; 332. Partition plate; 33. Sewage pipe; 334. Sewage tank; 335. Water supply pipe; 336. High-efficiency composite absorbent storage box; 4. Distributed monitoring sensor; 5. Oxygen generator; 51. Controller; 52. Air compressor; 53. Molecular sieve adsorption tank; 54. Oxygen storage tank; 55. Oxygen delivery pipeline; 6. Air intake shaft; 7. Regulating damper; 8. Bottom yard; 9. Working face; 10. Transport roadway; 11. Air intake roadway; 12. Return air roadway; 13. Controllable fresh air supply duct. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings.

[0020] This invention discloses a pressurized oxygen supply and circulation ventilation system for high-altitude mines.

[0021] Reference Figure 1 A pressurized oxygen supply and circulation ventilation system for high-altitude mines is mainly composed of a main circulation fan module, a waste air purification module, a precise oxygen supply module, a controllable fresh air supply module, and an intelligent monitoring and control module. It aims to specifically solve the technical problems of insufficient ventilation and oxygen supply, high energy consumption, and high safety risks in mines under high-altitude, low-pressure, and low-oxygen environments, and achieve dual optimization of airflow circulation reuse and precise oxygen supply.

[0022] The main circulating fan module includes a variable frequency main fan 1, a return air shaft 2, an intake air shaft 6, a transport roadway 10, an intake airway 11, and a return airway 12, which are used to establish and maintain stable power for the circulating air path. The variable frequency main fan 1 can operate dynamically according to the instructions of the intelligent monitoring and control module. By adjusting the speed, it changes the total air volume and air pressure of the circulating air path, ensuring that the airflow can effectively carry and distribute the oxygen-enriched air injected by the precise oxygen supply module, while meeting the air volume requirements of the waste air purification module and the controllable fresh air supply module. The main circulating fan module drives the airflow through the variable frequency main fan 1 to flow sequentially through the intake air shaft 6, the bottom yard 8, the transport roadway 10, the intake airway 11, the working face 9, the return airway 12, and the return air shaft 2, forming a complete circulating air path, providing the necessary airflow power foundation for waste air purification, fresh air supply, and precise oxygen supply.

[0023] The waste air purification module is responsible for the deep purification of the circulating airflow. The waste air purification module and the controllable fresh air supply module are connected in parallel. Both are connected to the return air treatment front end of the circulating air path driven by the variable frequency main fan 1 to achieve the purification and circulation of the airflow and the supply of fresh air.

[0024] Reference Figure 3 and Figure 4 The wastewater purification module includes a dust removal and adsorption device 3, which consists of a cyclone dust removal device 31, a harmful gas adsorption device 32, and a water tank 33. The air inlet 311 of the cyclone dust removal device 31 is fluidly connected to the return air side of the circulating air path. The inlet of the harmful gas adsorption device 32 is connected in series with the outlet of the cyclone dust removal device 31. The water tank 33 is located below the cyclone dust removal device 31 and the harmful gas adsorption device 32 and is fluidly connected to the sewage discharge channel 317, forming a complete purification chain of dust removal, harmful gas adsorption, and sewage collection.

[0025] Inside the casing of the cyclone dust collector 31, along the airflow direction from the air inlet 311, a water sprayer 312, an impeller 313, a circular guide plate 314, guide vanes 315, and a dehydration device 316 are installed sequentially. The water sprayer 312 is installed on the inner wall of the air inlet 311 of the cyclone dust collector 31 and is used to spray water mist containing a high-efficiency composite absorbent. The impeller 313 is located downstream of the water sprayer 312 and connected to the motor output end. The circular guide plate 314 is fixed to the side of the impeller 313 away from the water sprayer 312, so that the cross-section of the flow channel suddenly narrows along the airflow direction. The two work together to generate high-speed airflow. The flow fully atomizes the water droplets, greatly increasing the contact efficiency between the water mist and dust and harmful gases; the guide vane 315 is connected to the rotating output end of the motor and is located downstream of the circular guide plate 314. When it rotates at high speed, it uses centrifugal force to throw the water droplets wrapped with dust onto the wall of the device, and then guides them into the sewage channel 317 at the bottom of the cyclone dust collector 31, and finally flows into the water tank 33; the dehydration device 316 is fixed inside the outlet end of the cyclone dust collector 31, which can effectively separate the water droplets remaining in the airflow, ensure the subsequent gas purification effect, and output the pretreated gas smoothly to the harmful gas adsorption device 32.

[0026] The main components of the high-efficiency composite absorbent are oxidant components, alkaline absorbent, catalyst, complexing agent and auxiliary additives; the percentages of each component below are all mass percentages, based on the total mass of the finished high-efficiency composite absorbent; The oxidant components are 20-25% potassium permanganate (KMnO4), 3-5% sodium hypochlorite (NaClO), and 2-5% sodium persulfate (Na2S2O8). The oxidant components are the core active components of this reagent, responsible for oxidizing NO, which is sparingly soluble in water, into easily absorbed NO2, and oxidizing CO into CO2. The alkaline absorbent consists of 15-20% sodium hydroxide (NaOH), 10-15% sodium carbonate (Na2CO3), and 5-10% potassium hydroxide (KOH). The alkaline absorbent can absorb acidic gases such as NO2, CO2, and H2S, and can also adjust the pH of the solution to provide a suitable acid-base environment for the oxidation reaction. The catalyst components are 2-4% copper sulfate (CuSO4·5H2O), 1-3% ferrous sulfate (FeSO4·7H2O), 1-2% cerium nitrate (Ce(NO3)3), and 1-2% manganese dioxide (MnO2). The catalyst is used to accelerate the redox reaction, reduce the activation energy of the reaction, and improve the purification efficiency. The complexing agent component is 5-8% disodium EDTA (C 10 H 14 N2Na2O8), 3-5% sodium citrate (Na3C6H5O) 72-3% triethanolamine (TEA); complexing agents are used to form stable complexes with metal ions, preventing metal ion precipitation, and enhancing the selective absorption of harmful gases. The auxiliary additives consist of 0.5-1% sodium benzoate (C7H5NaO2), 0.3-0.8% sodium dodecylbenzenesulfonate (SDBS), 1-2% sodium silicate (Na2SiO3), and 0.2-0.5% thiourea (CH4N2S). These auxiliary additives are used to improve the performance and storage stability of the high-efficiency composite absorbent in mining environments.

[0027] The preparation steps of the high-efficiency composite absorbent are as follows: S1. Solution preparation: Add 60% deionized water to a stirred reactor and heat to 40-50℃. S2. Dissolution of alkaline components: Slowly add sodium hydroxide and sodium carbonate under stirring conditions, and stir until completely dissolved; S3. Addition of oxidant: After the solution cools to below 30°C, slowly add potassium permanganate and continue stirring for 30 minutes; S4. Catalyst dissolution: Dissolve copper sulfate and ferrous sulfate separately in a small amount of deionized water and then slowly add them to the reaction vessel; S5. Adding complexing agent: Add disodium EDTA and sodium citrate, and stir until completely dissolved; S6. Additive addition: Add ethylene glycol, sodium benzoate and sodium dodecylbenzene sulfonate in sequence, and stir until well mixed; S7. Volumetric Filtration: Add deionized water to the specified volume, filter to remove insoluble matter, and obtain the finished product.

[0028] A partition 332 is vertically fixed inside the water tank 33, dividing its interior into a clean water tank 331 and a wastewater tank 334. The outer wall of the clean water tank 331 is equipped with a water supply pipe 335 and a high-efficiency composite absorbent storage box 336. The outlet end of the water supply pipe 335 extends vertically to the upper part of the clean water tank 331 and forms a fluid connection, which can continuously replenish the water source required for purification. The high-efficiency composite absorbent storage box 336 is fixed to the outer wall of the water tank 33 and connected to the clean water tank 331. It can intelligently adjust the amount of additive according to the concentration of harmful gases. The bottom of the wastewater tank 334 is connected to a drain pipe 333, which is used to discharge the wastewater after adsorbing dust and harmful gases, ensuring the continuous and stable operation of the water tank 33.

[0029] The harmful gas adsorption device 32 has a secondary dehydrator 321 and a harmful gas adsorption plate 322 arranged sequentially along the airflow direction inside. The secondary dehydrator 321 is fixed at the inlet end of the harmful gas adsorption device 32. The secondary dehydrator 321 has a built-in high-efficiency hydrophobic membrane component, such as a PTFE hollow fiber hydrophobic membrane component. Its inlet is sealed to the outlet of the dehydration device 316 of the cyclone dust collector 31, which can further remove residual water vapor in the circulating airflow, prevent the subsequent adsorbent from getting damp and caking, and ensure the long-term stable operation of the adsorption device.

[0030] The harmful gas adsorption plate 322 is arranged in multiple parallel layers along the airflow direction downstream of the secondary dehydrator 321. It adopts a modular multi-layer structure design and is detachably connected to the inner wall of the shell by buckles or bolts for easy on-site maintenance and replacement. It is filled with a modified composite adsorbent. The modified composite adsorbent uses high specific surface area activated carbon as the base material and is modified by loading active components such as copper oxide and zinc oxide. It can efficiently remove toxic and harmful gas components such as carbon monoxide and nitrogen oxides from the circulating airflow. The air outlet 323 of the harmful gas adsorption device 32 is fluidly connected to the return air side of the circulating air path through a pipeline. After the modified composite adsorbent is saturated, it can be recycled through a thermal regeneration process, which takes into account both purification effect and economy.

[0031] Reference Figure 5 The precise oxygen supply module is responsible for the preparation and precise delivery of oxygen-enriched air, including an oxygen generator 5 and an oxygen delivery pipeline 55. Inside the housing of the oxygen generator 5, there is a controller 51, an air compressor 52, two molecular sieve adsorption tanks 53 and an oxygen storage tank 54. The controller 51 is electrically connected to the valve assemblies of the air compressor 52 and the molecular sieve adsorption tanks 53 through signal lines to realize the coordinated control of each component. An air compressor 52, a molecular sieve adsorption tank 53, and an oxygen storage tank 54 are sequentially fluidly connected. The molecular sieve adsorption tank 53 is filled with a high specific surface area modified zeolite molecular sieve, such as a high silica-alumina ratio acid-resistant NaY molecular sieve. After special processing, this modified zeolite molecular sieve exhibits higher adsorption selectivity for nitrogen molecules than oxygen. Utilizing the stronger polarity of nitrogen molecules and their better matching of kinetic diameter with the pore size of the molecular sieve, nitrogen molecules are rapidly adsorbed and locked in the microporous structure under pressure. Meanwhile, oxygen, argon, and other gas molecules, due to their weaker polarity, are difficult to adsorb and can directly pass through the adsorption layer and collect from the adsorption tank outlet into the oxygen storage tank 54. When one of the molecular sieve adsorption tanks 53 reaches adsorption saturation, the system automatically switches to a depressurization desorption mode. By releasing the pressure, the adsorbed nitrogen is rapidly desorbed and discharged. Simultaneously, the other molecular sieve adsorption tank 53 enters a pressurized adsorption state. Through the periodic alternation of adsorption and desorption, continuous preparation of oxygen-enriched air is achieved. The outlet of the oxygen storage tank 54 is sealed to one end of the oxygen delivery pipeline 55. The oxygen delivery pipeline 55 is arranged along the roadway, with several oxygen supply ports at the end and extending to oxygen-required areas such as the underground working face 9 and the chamber, so as to achieve the core goal of on-demand replenishment and precise oxygen control.

[0032] The controllable fresh air supply module is used to dynamically adjust the fresh air supply volume. It includes a controllable fresh air supply duct 13, which forms a parallel branch with the waste air purification module in terms of air path connection. One end of the controllable fresh air supply duct 13 is connected to the fresh air source outside the mine, and the other end is connected to the return air side of the main circulation air path. A flow sensor is installed on the pipeline of the controllable fresh air supply duct 13. The flow sensor is connected to the intelligent monitoring and control module to realize the accurate monitoring and control of the fresh air volume.

[0033] The intelligent monitoring and control module is the core hub for the coordinated operation of the system. It includes a main control unit, distributed monitoring sensors 4, and a signal transmission module. The main control unit is located in the mine surface monitoring room or underground chamber. It is connected to the distributed monitoring sensors 4 and the execution components of each module through the signal transmission module, forming a comprehensive data acquisition and control network.

[0034] Distributed monitoring sensors 4 are installed at key locations including the underground working area, return airway 12, intake airway 11, the waste air purification module, and the precision oxygen supply module. The intelligent monitoring and control module collects core safety parameters through these sensors, including the concentrations of oxygen, carbon monoxide, carbon dioxide, dust, methane, and nitrogen oxides, as well as atmospheric pressure, temperature, and roadway wind speed. Simultaneously, it receives real-time operating data from each functional module, covering the dust removal efficiency and adsorption saturation of the waste air purification module, the valve opening, fresh air flow, and fan operating power of the controllable fresh air supply module, the oxygen concentration, oxygen supply, and oxygen generator 5 operating pressure of the precision oxygen supply module, and the variable frequency speed, actual air pressure, and air volume of the main circulating fan module. This enables real-time matching of environmental requirements and equipment status. The intelligent monitoring and control module supports collaborative operation with the central monitoring platform, allowing remote viewing of the collaborative status of multiple modules and manual intervention of collaborative strategies via web and mobile terminals. It also reserves interfaces for future intelligent upgrades.

[0035] When the intelligent monitoring and control module detects that the concentration of harmful gases in the well is within a safe range, the system mainly operates with the waste air purification module, so that the circulating air is treated by the cyclone dust collector 31 and the harmful gas adsorption device 32 and reused. Only the minimum necessary fresh air volume is introduced through the controllable fresh air supply module. When the intelligent monitoring and control module detects that the concentration of any harmful gas exceeds the preset safety threshold, the fresh air volume of the controllable fresh air supply module is quickly increased from the minimum necessary air volume to the rated air volume to quickly eliminate the risk of excessive harmful gases and realize the dual functions of energy-saving circulation and emergency purification.

[0036] A regulating damper 7 is configured on the return air side of the tunnel. Based on the laws of high-altitude air fluid dynamics, the intelligent monitoring and control module dynamically calculates the optimal wind resistance threshold according to real-time data collected by distributed sensors, and automatically controls the opening of the regulating damper 7. By increasing or decreasing the local wind resistance on the return air side, the overall wind pressure of the circulating air path is adjusted. By controlling the regulating damper 7 to decrease its opening, the local wind resistance on the return air side can be increased, forcing fresh air and oxygen-rich air to converge more efficiently at the working face, thereby increasing the oxygen partial pressure at the working face. When the working face pressure is too high or the ventilation resistance is too high, causing the fan load to exceed the standard, the opening of the regulating damper 7 is automatically increased to reduce the return air resistance and ensure a balance between system energy consumption and ventilation efficiency.

[0037] During the process of adjusting the resistance and increasing the pressure of the damper 7, the intelligent monitoring and control module simultaneously sends a speed correction command to the frequency converter of the main circulation fan module, and dynamically optimizes the frequency converter parameters of the fan according to the change of air resistance, so as to avoid air volume fluctuations caused by single resistance adjustment. If the concentration of harmful gases fluctuates during the pressure adjustment process, the intelligent monitoring and control module will simultaneously link with the controllable fresh air supply module to adjust the fresh air volume, ensuring that the pressure increase does not affect the dilution effect of harmful gases, and realizing closed-loop control of "on-demand sensing - dynamic pressure adjustment - precise pressure increase".

[0038] Reference Figure 6 The system is configured with a dual-mode intelligent operation mechanism, which switches modes through real-time data feedback from the intelligent monitoring and control module; the two modes are as follows: Normal Circulation Mode: This mode represents the system's regular operating state, achieving dual optimization of energy-saving circulation and precise oxygen supply, suitable for downhole conditions where harmful gas concentrations meet standards and oxygen demand is stable. The controllable fresh air supply module operates at the minimum necessary air volume, introducing only fresh air to meet basic gas replacement requirements, minimizing energy consumption for fresh air pretreatment and delivery; the main circulation fan module uses frequency conversion control, maintaining its speed at 10%-30% of the rated speed, driving the airflow to circulate stably within the circulation path at an appropriate wind speed, avoiding loss of air volume and fresh oxygen; and relying on the intelligent monitoring and control module to monitor data in real time, intelligently adjusting the damper 7 to achieve on-demand resistance adjustment and pressurization. In the airflow circulation path, the air first undergoes deep treatment by the polluted air purification module, and the cyclone dust collector 31 operates at normal speed to remove dust particles from the circulating airflow; the harmful gas adsorption device 32 starts simultaneously, adsorbing CO and NO through a modified composite adsorbent. x Residual harmful gases are removed to ensure that the concentration of harmful gases in the purified airflow is below the safe threshold. The purified airflow enters the precision oxygen supply module, where oxygen-enriched air is injected by the pressure swing adsorption oxygen generator 5. The amount of oxygen supplied is dynamically adjusted based on the oxygen partial pressure data collected in real time by the intelligent monitoring module. At the same time, the wind speed of the main circulation fan is adjusted to ensure that the oxygen-enriched air is evenly diffused to the breathing zone of the work surface, avoiding local hypoxia or excessive oxygen. Emergency Dilution Mode: When the intelligent monitoring and control module detects that the concentration of harmful gases underground exceeds the preset safety threshold, it switches to emergency dilution mode. The core objective of this mode is "rapid dilution + safe oxygen supply" to prevent the accumulation of harmful gases and the resulting safety accidents. The controllable fresh air supply module increases the fresh air volume to 120%-150% of the rated air volume, all regulating dampers 7 are opened, and the main circulation fan module speed is increased to 80%-100% of the rated speed, driving the airflow to accelerate the dilution of harmful gases and quickly remove them. When the concentration of harmful gases drops below the safety threshold and stabilizes, the system automatically switches back to normal circulation mode to ensure that the oxygen concentration at the working face remains stable within a safe range, thus ensuring safe production in the mine.

[0039] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A pressurized oxygen supply and circulating ventilation system for high-altitude mines, characterized in that: It includes a main circulation fan module, a waste air purification module, a precise oxygen supply module, a controllable fresh air supply module, and an intelligent monitoring and control module; The main circulating fan module is used to establish and maintain stable power for the circulating air path, including the variable frequency main ventilation fan (1), return air shaft (2), intake air shaft (6), transport roadway (10), intake airway (11) and return airway (12); the main circulating fan module drives the airflow through the variable frequency main ventilation fan (1) to flow sequentially through the intake air shaft (6), the bottom yard (8), the transport roadway (10), the intake airway (11), the working face (9), the return airway (12) and the return air shaft (2), forming a complete circulating air path, providing the necessary airflow power foundation for sewage purification, fresh air supply and precise oxygen supplementation; The waste air purification module and the controllable fresh air supply module are connected in parallel branches. They are both connected to the return air treatment front end of the circulating air path driven by the main circulating fan module to achieve air purification and circulation and fresh air supply. The controllable fresh air supply module includes a controllable fresh air supply duct (13) for dynamically adjusting the fresh air supply volume. The waste air purification module includes a dust removal and adsorption device (3), which consists of a cyclone dust removal device (31), a harmful gas adsorption device (32), and a water tank (33). The inlet of the harmful gas adsorption device (32) is connected in series with the outlet of the cyclone dust removal device (31). The water tank (33) is located below the cyclone dust removal device (31) and is fluidly connected to the sewage discharge channel (317) of the cyclone dust removal device (31). The waste air purification module is used to deeply purify dust and harmful gases in the circulating airflow. The precise oxygen supply module is located in the intake airway (11), and the output end of the precise oxygen supply module is connected to the rear end of the circulating air path driven by the main circulating fan module. The precise oxygen supply module includes an oxygen generator (5) and an oxygen delivery pipeline (55). The oxygen generator (5) includes a controller (51), an air compressor (52), a molecular sieve adsorption tank (53), and an oxygen storage tank (54). The air compressor (52), the molecular sieve adsorption tank (53), and the oxygen storage tank (54) are connected in sequence. One end of the oxygen delivery pipeline (55) is connected to the oxygen storage tank (54), and the other end extends to the oxygen-required area underground. The intelligent monitoring and control module is used to collect environmental parameters and the operating status of each module, so as to realize the coordinated control of multiple modules.

2. The pressurized oxygen supply and circulating ventilation system for high-altitude mines according to claim 1, characterized in that: The variable frequency main fan (1) operates dynamically according to the instructions of the intelligent monitoring and control module. By adjusting its own speed, it changes the total air volume and air pressure of the circulating air path, ensuring that the airflow can effectively carry and distribute the oxygen-rich air injected by the precise oxygen supply module, while meeting the requirements of the sewage purification module and the controllable fresh air supply module for the processing air volume.

3. The pressurized oxygen supply and circulating ventilation system for high-altitude mines according to claim 1, characterized in that: The cyclone dust removal device (31) has a water sprayer (312), an impeller (313), a circular guide plate (314), guide vanes (315) and a dewatering device (316) installed in sequence from the air inlet (311) to the inside. The water sprayer (312) is installed on the inner wall of the air inlet (311) of the cyclone dust collector (31) and is used to spray water mist containing a high-efficiency composite absorbent. The impeller (313) is located downstream of the water sprayer (312) and is connected to the motor output end of the cyclone dust collector (31). The circular guide plate (314) is fixed to the side of the impeller (313) away from the water sprayer (312). The cross-section of the flow channel is reduced along the airflow direction by the circular guide plate (314), and works with the impeller (313) to generate a high-speed airflow to fully atomize the water droplets. To improve the contact efficiency between water mist and dust and harmful gases; the guide vane (315) is located downstream of the circular guide plate (314). When the guide vane (315) rotates at high speed, it uses centrifugal force to throw the water droplets wrapped with dust onto the wall of the device and guide them into the sewage channel (317) at the bottom of the cyclone dust collector (31), and finally into the water tank (33); the dehydration device (316) is fixed inside the outlet end of the cyclone dust collector (31) and is used to separate residual water droplets from the airflow and output the treated gas to the harmful gas adsorption device (32).

4. The pressurized oxygen supply and circulation ventilation system for high-altitude mines according to claim 3, characterized in that: The main components of the high-efficiency composite absorbent are oxidant components, alkaline absorbent, catalyst, complexing agent and auxiliary additives; the content of each component is expressed as a percentage by mass. The oxidant components are 20-25% potassium permanganate, 3-5% sodium hypochlorite, and 2-5% sodium persulfate; the oxidant is the core active component of this reagent, responsible for oxidizing NO, which is poorly soluble in water, into easily absorbed NO2, and oxidizing CO into CO2; The alkaline absorbent consists of 15-20% sodium hydroxide, 10-15% sodium carbonate, and 5-10% potassium hydroxide. The alkaline absorbent is used to absorb acidic gases and adjust the pH of the solution, providing a suitable acid-base environment for the oxidation reaction. The catalyst consists of 2-4% copper sulfate, 1-3% ferrous sulfate, 1-2% cerium nitrate, and 1-2% manganese dioxide. The catalyst is used to accelerate the redox reaction, reduce the activation energy, and improve the purification efficiency. The complexing agent consists of 5-8% disodium EDTA, 3-5% sodium citrate, and 2-3% triethanolamine. The complexing agent is used to form stable complexes with metal ions, preventing metal ion precipitation and enhancing the selective absorption of harmful gases. The auxiliary additives consist of 0.5-1% sodium benzoate, 0.3-0.8% sodium dodecylbenzenesulfonate, 1-2% sodium silicate, and 0.2-0.5% thiourea. These auxiliary additives are used to improve the performance and storage stability of the high-efficiency composite absorbent in mining environments.

5. A pressurized oxygen supply and circulating ventilation system for high-altitude mines according to claim 4, characterized in that: The preparation steps of the high-efficiency composite absorbent are as follows: S1. Solution preparation: Add 60% deionized water to a stirred reactor and heat to 40-50℃. S2. Dissolution of alkaline components: Slowly add sodium hydroxide and sodium carbonate under stirring conditions, and stir until completely dissolved; S3. Addition of oxidant: After the solution cools to below 30°C, slowly add potassium permanganate and continue stirring for 30 minutes; S4. Catalyst dissolution: Dissolve copper sulfate and ferrous sulfate separately in a small amount of deionized water and then slowly add them to the reaction vessel; S5. Adding complexing agent: Add disodium EDTA and sodium citrate, and stir until completely dissolved; S6. Additive addition: Add ethylene glycol, sodium benzoate and sodium dodecylbenzene sulfonate in sequence, and stir until well mixed; S7. Volumetric Filtration: Add deionized water to the specified volume, filter to remove insoluble matter, and obtain the finished product.

6. The pressurized oxygen supply and circulating ventilation system for high-altitude mines according to claim 3, characterized in that: The water tank (33) is vertically fixed with a partition (332) inside, which divides the inside of the water tank (33) into a clean water tank (331) and a sewage tank (334); The outer wall of the water purification tank (331) is provided with a water supply pipe (335) and a high-efficiency composite absorbent storage box (336); the outlet end of the water supply pipe (335) extends vertically to the upper part of the water purification tank (331) and is fluidly connected to the water purification tank (331); the high-efficiency composite absorbent storage box (336) is fixed to the outer wall of the water tank (33), and the outlet end of the high-efficiency composite absorbent storage box (336) is connected to the water purification tank (331), and the amount added to the water purification tank (331) is adjusted according to the concentration of harmful gases; the bottom of the sewage tank (334) is connected to a sewage pipe (333) for discharging sewage.

7. A pressurized oxygen supply and circulating ventilation system for high-altitude mines according to claim 6, characterized in that: The interior of the harmful gas adsorption device (32) is provided with a secondary dehydrator (321) and a harmful gas adsorption plate (322) in sequence along the airflow direction; The secondary dehydrator (321) is fixed at the inlet end of the harmful gas adsorption device (32) and has a built-in high-efficiency hydrophobic membrane assembly; the inlet of the secondary dehydrator (321) is sealed to the outlet of the dehydration device (316) to remove residual water vapor in the circulating airflow. The harmful gas adsorption plate (322) is arranged in multiple parallel layers along the airflow direction downstream of the secondary dehydrator (321), adopting a modular multi-layer structure design, and is detachably connected to the shell of the harmful gas adsorption device (32). The harmful gas adsorption plate (322) is filled with a modified composite adsorbent, which uses high specific surface area activated carbon as the substrate and is loaded with copper oxide and zinc oxide active components. The modified composite adsorbent can be recycled through a thermal regeneration process after saturation.

8. A pressurized oxygen supply and circulating ventilation system for high-altitude mines according to claim 7, characterized in that: The oxygen generator (5) has a controller (51), an air compressor (52), two molecular sieve adsorption tanks (53) and an oxygen storage tank (54) fixedly installed inside its housing; the controller (51) is electrically connected to the valve assemblies of the air compressor (52) and the molecular sieve adsorption tanks (53) respectively through signal lines; The molecular sieve adsorption tank (53) is filled with high specific surface area modified zeolite molecular sieve. The molecular sieve has a higher adsorption selectivity for nitrogen molecules than for oxygen. Under pressure, nitrogen molecules are adsorbed and locked in the microporous structure by the molecular sieve, while oxygen molecules and argon molecules pass through the adsorption layer and gather in the oxygen storage tank (54). When one of the molecular sieve adsorption tanks (53) reaches adsorption saturation, the oxygen generator (5) system automatically switches to depressurization desorption mode, releases pressure to allow nitrogen to desorb and be discharged quickly, and at the same time, the other molecular sieve adsorption tank (53) enters the pressurized adsorption state. Through periodic alternation, oxygen-enriched air is continuously prepared. The outlet of the oxygen storage tank (54) is sealed to one end of the oxygen delivery pipeline (55), which is used to deliver oxygen-enriched air to the oxygen-required working area.

9. A pressurized oxygen supply and circulating ventilation system for high-altitude mines according to claim 8, characterized in that: The intelligent monitoring and control module includes a main control unit, a distributed monitoring sensor (4), and a signal transmission module. The main control unit is connected to the distributed monitoring sensor (4) and the execution components of each functional module through the signal transmission module. The intelligent monitoring and control module collects core safety parameters through the distributed monitoring sensor (4), including the concentrations of oxygen, carbon monoxide, carbon dioxide, dust, methane, and nitrogen oxides, as well as atmospheric pressure, temperature, and roadway wind speed. It also receives real-time operating data from each functional module, including the dust removal efficiency of the waste air purification module and the adsorption saturation of the harmful gas adsorption unit; the valve opening, fresh air flow, and fan operating power of the controllable fresh air supply module; the oxygen concentration, oxygen supply, and working pressure of the oxygen generator (5) of the precise oxygen supply module; and the variable frequency speed, actual wind pressure, and air volume of the main circulation fan module. The intelligent monitoring and control module supports collaborative linkage with the central monitoring platform and can remotely view the collaborative status of multiple modules and manually intervene through the Web terminal and mobile terminal. It also reserves an intelligent upgrade interface. The controllable fresh air supply module and the waste air purification module form a parallel branch in the air path connection; when the intelligent monitoring and control module detects that the concentration of harmful gas is within the safe range, the system mainly operates the waste air purification module, so that the circulating air is treated by the cyclone dust collector (31) and the harmful gas adsorption device (32) and reused, and the controllable fresh air supply module only introduces the minimum necessary fresh air volume; when the intelligent monitoring and control module detects that the concentration of any harmful gas exceeds the preset safety threshold, the fresh air supply volume of the controllable fresh air supply module is increased from the minimum necessary air volume to the rated air volume to quickly eliminate the risk of harmful gas exceeding the standard; An adjustable damper (7) is configured on the return air side of the roadway. The intelligent monitoring and control module dynamically calculates the optimal wind resistance threshold based on the real-time data collected by the distributed sensors, and automatically controls the opening of the adjustable damper (7). By increasing or decreasing the local wind resistance on the return air side, the overall wind pressure of the circulating airway is adjusted. During the process of adjusting resistance and increasing pressure, the intelligent monitoring and control module synchronously sends a speed correction command to the frequency converter of the main circulation fan module and dynamically optimizes the frequency converter parameters of the fan according to the change of wind resistance. If the concentration of harmful gases fluctuates during the pressure adjustment process, the intelligent monitoring and control module will simultaneously link with the controllable fresh air supply module to adjust the fresh air volume, ensuring the dilution effect of harmful gases while increasing pressure.

10. A pressurized oxygen supply and circulating ventilation system for high-altitude mines according to claim 9, characterized in that: The system is configured with a dual-mode intelligent operation mechanism, which achieves mode switching through real-time data feedback from the intelligent monitoring and control module. The two operation modes are as follows: Normal circulation mode: It is suitable for working conditions where the concentration of harmful gases meets the standard and the oxygen demand is stable. The controllable fresh air supply module operates with the minimum required air volume, the main circulation fan module speed is maintained at 10%-30% of the rated speed, the airflow is reused after being treated by the sewage purification module, the precise oxygen supply module dynamically adjusts the oxygen supply amount according to the oxygen partial pressure data, and the intelligent monitoring and control module realizes on-demand resistance adjustment and pressure increase by adjusting the damper (7). Emergency Dilution Mode: When the intelligent monitoring and control module detects that the concentration of harmful gas in the well exceeds the preset safety threshold, it switches to emergency dilution mode; the controllable fresh air supply module increases the fresh air volume to 120%-150% of the rated air volume, the regulating damper (7) is fully opened, and the speed of the main circulation fan module is increased to 80%-100% of the rated speed, driving the airflow to accelerate the dilution of harmful gas; when the concentration of harmful gas drops below the safety threshold and stabilizes, the system automatically switches back to normal circulation mode.

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