Coal mine ventilation technology

According to many coal mine accident investigation results show that the major disasters of the coal mine, and mine ventilation systems are generally closely linked. Mine ventilation system is a key part of coal mine safety. Therefore, it is especially important to establish a stable, reliable and simple ventilation system. The variability of coal mine production determines the dynamics of mine ventilation system. It must adopt high-tech means, introduce advanced technology, use automatic management system, regularly test, inspect and evaluate various ventilation parameters, and collect and analyze the operation information of ventilation system in time. Formulate the optimal airflow adjustment plan for each production period, forecast the long-term operation status of the ventilation system, improve the mine ventilation management level, and use the expert system and decision support system and theory to formulate the wind flow dispatching plan during the disaster period to improve the disaster prevention and relief of the coal mine. ability.

1. Status of mine ventilation equipment.

(1) Mine main fan. Most of the main fans used in coal mines in China are pump-out ventilators. In terms of structural form, most coal mines use axial-flow ventilators, and fewer centrifugal ventilators are used. Most of the main ventilation fans in the mine are designed and manufactured by themselves. The main technical indicators are: the designed maximum air volume is 300-400m3/s, and the maximum wind pressure is 5000-6000Pa. The fan efficiency is greater than 80%.

(2) Local ventilator. In the past ten years, the local ventilators designed and manufactured in China have improved significantly in terms of technical level and performance parameters. The successful KDZ-1 type press-in counter-rotating local ventilator has a power of 2x26kw and a working air volume of 250-450m3/ Min, the working wind pressure reaches 6600-2500Pa, the total pressure efficiency is 80%, and the noise is no more than 15dB. Due to its high working pressure, it can supply air for long distances and ensure the supply of air on the working surface. At present, the counter-rotating local ventilator has formed a series of products that can meet the needs of local ventilation in coal mines.

(3) Air duct. Coal mine air duct is an indispensable part of local ventilation, with wide use and large consumption. Since the air duct must be continuously operated in an explosive atmosphere, in addition to good ventilation, it should have reliable safety performance and specified strength. The former Ministry of Coal has promulgated a series of standards for the use of wind tunnel products for coal mines, and has formed a complete standard system for wind turbine products for coal mines.

The earliest use of coal mine rigid metal duct, fiberglass duct began to promote in the 1980s, but due to underground transport inconvenience, multi-joint, large air leakage, is now rarely used. In recent years, a flexible and flexible air duct with a rigid skeleton has been developed, that is, a traveler or a spiral spring traveler is added at regular intervals in the air duct, which can be used for extractive ventilation and bear a certain negative The pressure has the characteristics of being contractible, and is convenient to use than the metal air cylinder and the glass fiber reinforced air cylinder.

The flexible air cylinder is the most widely used air duct at present, and has the advantages of being lightweight, retractable, convenient to disassemble and assemble, and can be folded when not ventilated. A large number of flexible air cylinders used in coal mines are made of glass fiber, chemical fiber and other mixed fabrics (mainly glass fiber cloth), coated with rubber, plastic or rubber coated cloth. Among them, the rubber air cylinder is used earlier, and its flame retardant, antistatic and softness are better, but it is more cumbersome and aging. Plastic duct easily improved its initial application hardening, cold poor, disadvantages easily repaired, due to manufacture process is simple, no pollution talc, lighter weight, lower prices and other advantages has been gradually popularized. The rubber-coated air duct overcomes the shortcomings of the former two, and has unique cold and heat resistance properties, and has also been applied to a certain extent. In recent years, the development of the PVC plastic coated cloth positive pressure air cylinder, less wind resistance than the rubber air cylinder, long life, light weight, low price, good flame retardancy, suitable for high wind pressure long distance ventilation. However, PVC plastics have a large amount of smoke, whether they are flaming or flameless. Reducing the amount of smoke is an important part of the current flame retardant technology of this product. With the mature technology of plastic air duct flame retardant technology and rapid sticking technology at normal temperature, its promotion and application prospects will be broader.

2. Mine main fan monitoring and monitoring

In recent years, many colleges and research institutes have developed a variety of monitoring, monitoring and fault diagnosis systems or instrumentation of main fans, and have carried out tests and applications on the spot, and achieved good results.

The online monitoring and communication system of mine main ventilator developed by China University of Mining and Technology. The method of monitoring air volume solves the key technical problems of dust, moisture, pulsation, reliability and accuracy of online monitoring under the harsh ventilation conditions of mines. The automation and scientific management level of mine ventilation equipment. The system can perform on-line monitoring of the performance parameters of the main ventilator and periodic measurement of the performance curve of the ventilator. It can realize the communication networking between the ventilator room and the administrative departments such as electromechanical department, ventilation department and dispatching room. The system is put into use in Baodian Coal Mine of Yankuang Group Co., Ltd., Jining No. 2 Coal Mine, Jining Xuchang Coal Mine, etc. The system performance is reliable so far, and it is in the forefront of online monitoring and monitoring of domestic main ventilation fans.

The ZF-1 intelligent ventilation multi-parameter tester developed by Fushun Branch of the Coal General Hospital can simultaneously measure three ventilation parameters: pressure, temperature and wind speed.

In addition, the Shanghai Branch of the Coal Science Institute, Shanxi Mining College, Liaoning University of Engineering and Technology, Xi'an Mining Institute and other scientific research institutions and schools have also developed different mine main fan online monitoring and monitoring systems, and have achieved good results through field applications. effect.

In recent years, fault diagnosis has also been applied to a certain extent in the online monitoring and monitoring of mine main fans. For example, the FJz mine main ventilator online monitoring and fault diagnosis instrument developed by the Chongqing Branch of the Coal Science Research Institute conducts various parameters such as vibration intensity, shaft trajectory, shaft temperature, air volume, negative pressure, current and voltage of the ventilator. Real-time monitoring, automatic diagnosis of common mechanical faults, after networking with the whole mine monitoring main system, can send the fan operating status information to the ground central station in time.

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