Analysis of spontaneous combustion and explosion causes of air compressors, analysis of spontaneous combustion and explosion of air compressors Yang Yongteng 1 Zhao Shiqi 1 Department of Mechanical Engineering, Shandong University of Science and Technology, Tai'an 271000, Shandong 2 Shandong Haili Group 1 equipment is the main power equipment of the mine. Among them, the air compressor + is the heart of the mine gas pressure system. Because the air compressor uses the mineral oil to reduce the oil as the lubricating oil, the lubricating oil along with the gas pressure process along the entire exhaust passage, the cylinder valve chamber tube cooler and the gas storage tank, etc. The formation of oil deposits, which can spontaneously ignite under certain conditions, causes the explosion of the air compressor device. This phenomenon is common in all producing countries. Five years ago, the Shiqiao Coal Mine of Shandong Haili Group had a suffocation accident involving air-fired gas storage tanks, which almost caused a vicious accident of the whole machine and pipe network explosion. In the past few years, we have analyzed some of the experiences of such accidents in air compressor installations through analysis and field experiments, and provided on-site personnel with reference for the rational use management and technical transformation of air compressor installations.
Shiqiao Coal Mine is a local state-owned small coal mine. The ground pressure air blower station is equipped with 4 sets of 4120 and 8 air compressors. On September 12, 1999, it was night shift. There were two rock roads in the underground, and the two heads were rushing to work at the same time. An abnormal smell appeared in the air. When the captain of the class thought that the harmful gas in the rock layer overflowed, the worker was arranged to open the pressure air line to dilute the harmful gas, but the odor was more intense, and then the scene personnel had dizziness and two people fainted. They immediately stopped their work and evacuated the scene. During this period, another situation occurred in the other headings. After the dispatching room received the report, the ground air compressor station reported urgently, and the air tank casing smoked and was shut down. After inspection, all the shells of the gas tanks were completely detached due to the high temperature paint layer, and the manholes were opened from the inside of the gas storage tanks to remove 0.3, char, and the accident was prevented by the decisive treatment of the air compressor driver to prevent the gas tanks and even the whole machine from exploding. In the event of an accident, a worker who is rushing to the ground and rushing to the wind will also cause serious poisoning.
The direct cause of the accident was the lack of strict scientific management of the equipment, resulting in excessive carbon deposits inside the air compressor unit. The amount of carbon removed from the gas storage tank was converted to 40. Above, the spontaneous combustion of the gas storage tank will become natural.
1 The cause of the internal combustion and explosion of the air compressor is the lubricating oil accompanying the airflow in the cylinder exhaust pipe valve cooler and the separator. The light fractionated oxide evaporated under the action of high temperature forms acid pitch and other Carbide, these deteriorations are combined with the increased dust suction piston and the metal particles worn by the cylinder to mix with the oil and gas, and after the compressor oil is discharged from the cylinder, it is formed on the wall of each part where the exhaust passage passes. Deposit deposits. Oxidation of the coke produces an exotherm that is normally cooled by the air on the carbon deposit and carried away by the carbon deposit to the metal wall that is in contact. When the working pressure or temperature of the air compressor rises sharply and exceeds its limit value, including the deposition thickness, the heat balance between the lost deposit, the heat release and the heat dissipation of the air compressor will be broken, and the temperature of the carbon deposit layer will rise sharply, causing deposition. The object achieves self-ignition in the exhaust system, which propagates along the exhaust pipe system, eventually causing the explosion of the compressor system.
If the quality of the lubricating oil is unqualified, it is necessary to use pure and non-impurity compressor oil.
0 neglect management, irregular cleaning, can not timely discharge oil in the oil separator gas tank is the main reason for the spontaneous combustion of gas storage tanks in Shiqiao Coal Mine.
3 excessive oil supply will promote the formation of carbon deposits.
6 system cooling effect is not good, high temperature accelerates oxidation.
6 The presence of catalysts 6 and 6, such as particles, will also accelerate the oxidation of the oil.
For mining pressure, when the pressure is too large, the throttle valve should be adjusted in time. The throttle valve rotates clockwise to reduce the rig pressure and the propulsion speed. Conversely, the pressure and propulsion speed of the two-stage hydraulic cylinder are connected to the rear of the frame; the other end 6 is connected to the carriage. The two-stage hydraulic cylinder has two oil ports respectively connected with the two oil ports on the multi-way reversing valve on the operating table with high-pressure hose. When the multi-way reversing valve is operated, the power head can be advanced or retracted. 4 Performance characteristics 1 The rig adopts a column-type frame structure, which has large anchoring force, complete machine stability, can withstand large drilling reaction force, safe and reliable at work, and good disintegration of the rig. It is convenient for disassembly and maintenance and handling, and the operator has low labor intensity and adopts rig. Hydraulic propulsion, large propulsion, long propulsion length, and propulsion speed can be adjusted according to drilling resistance. The main engine power is used for drilling and drilling. The drilling efficiency is high. 3 The drilling machine adopts 2 soft rock drill pipe or taper thread connection drill pipe. The connection is convenient and fast, especially suitable for drilling deep holes.
5 The main purpose of the 075 electric drilling rig was approved by the State Administration of Work Safety in December 2004. It is mainly used for drilling underground coal mines. It is suitable for drilling gas drainage holes in gas mines at all levels to detect discharge holes and other engineering holes, such as water exploration and drainage holes in coal seams or soft rocks. Practice Example of Renovation Engineering of Mouth Ventilation System Sun Huanjie Nanjing Design and Research Institute of China Coal International Engineering Group Nanjing Nanjing 210031 Mine was put into operation in the late 1960s. The original mine design production capacity was 1.5 million years, and the mine design capacity was 2.4 million. 1 year. The mine is rich in reserves, but the coal seams have complex conditions and high gas content, which is a high gas mine.
With the gradual improvement of coal mine production, the mining level is getting deeper and deeper, the gas content is increasing, the ground temperature is increasing, the production system is more and more complicated, and the mine ventilation safety has become an urgent need for the safety production of coal mines. Therefore, it is necessary to reform the mine ventilation. The system optimizes the ventilation network, reduces the resistance of the roadway, makes the mine ventilation system more reasonable, and at the same time, through the transformation of the ventilation facilities, the equipment operation performance is more safe and reliable. The mine ventilation mode is the extraction type, and the central boundary two wings are divided into two series of series fans, one set. Work, 1 spare. The fan has been in operation for nearly 20 years and is already a phase-out product with insufficient performance. With the adjustment of the layout of the mining area in the west of the mine, the wind volume undertaken by the Xifeng Well is increased, and the performance of the original wind turbine cannot meet the ventilation requirements. The ventilation well ventilation equipment must be reconstructed as soon as possible.
1 West wind well ventilation and renovation The original Westwind well ventilation room is equipped with two 260 axial flow ventilators. The fan room is equipped with a 5-shaped curved motor room and a ventilator room. The long shaft drive is used between the motor and the ventilator. The carbon sequestration of the self-burning sulphuric acid is a flammable material with an oil content of 30. When the temperature reaches the limit of combustion, it will burn. The possibility of generating a high-temperature fire source has several mismatches or insufficient lubrication. , the formation of mechanical impact and spark; 0 hard particles in the impact of movement, such as soot particles, may produce sparks (1) electrostatic discharge to produce sparks (4) ambient temperature gas temperature is too high 4 to promote the explosion of small serotonin compressed air, degree If the temperature of the compressed air exceeds a certain limit value, it will cause the deposit to accelerate the automatic heating of the oxidation, resulting in spontaneous combustion.
The extreme temperature of spontaneous sedimentation of sediments in sediments is closely related to its thickness. The temperature of the exhaust gas does not increase, and the deposition thickness increases continuously, which will reduce the original auto-ignition temperature limit and spontaneous combustion. If the thickness of the sediment is 1mm, the auto-ignition limit temperature is 160C; if the thickness is 2, the limit value will be reduced to 150.
Studies of changes in exhaust flow rate have shown that the autoignition temperature limit is reduced when the flow rate of compressed air in the line is reduced. For example, the compressed air flow rate is reduced in the expansion part of the air compressor exhaust line, and the compressed air temperature here is quite high. The exhaust manifold gas storage tank is the most sensitive area, and the gas compressor is often exploded. After the cylinder. It should be emphasized that if the lubricating oil deposit in the exhaust manifold is quite thick and the exhaust temperature is high, then the air compressor will stop or the operating condition will be unloaded and the non-gas flow rate will suddenly drop or even drop to zero. It is prone to the danger of spontaneous combustion of sediments.
The humidity of the compressed air 0 generates a large amount of superheated water during the compression process due to the increase of the humidity of the intake air, and the deposit is a loose structure, which adsorbs the superheated steam in a large amount and dissipates heat, so that the exhaust gas temperature rises. It can also cause spontaneous combustion of lubricating oil deposits. Shang Shishao, the air compressor unit of the former Donbass mine in the Soviet Union, had three foggy days since the accident, and the influence of the inhalable air humidity was great.
6 During the automatic unloading process, the temperature of the exhaust gas is increased, causing the two parts of the spontaneous combustion explosion of the oil deposit to start unloading. The stage suction valve is affected by the resistance of the network and the internal volume, and the additional reaction of the intermediate pressure. The action time will lag 1.525 than the level suction valve. During this time, the suction valve is still in normal working state. At this time, the compression changes, which will cause the stage exhaust temperature to rise rapidly. 1 When the unloading is over, it will resume normal operation. When the air staying between the filter and the stage cylinder is heated by the cylinder and the piston, the hot air is taken in at this time, and the suction temperature of the normal stage is about 28, and the suction temperature can be as high as 150, and then compressed, and the special thermometer is calculated and used. Test, the second exhaust temperature can be as high as 250, far exceeding the normal exhaust temperature. If you unload frequently, it is very dangerous.
5 The theory and practice of the explosion mechanism of air compressors confirmed that the oxidation of carbon is carbon oxide, which is dominant, and that 0 is the initial product of carbon and chemical surface. Therefore, the oil deposits in the air compressor device form a large amount after spontaneous combustion. When the high temperature pressure gas contains 1.5, 7.5 of 0, it can explode and produce a highly toxic hazard.
After the explosion of the air compressor device, in addition to the main explosion source, the detonation wave propagates along the pipeline up to 300,500, and multiple explosion points may occur. The conditions of the detonation wave propagation are (1) the presence or absence of a mixture of incomplete combustion in the pipeline; and (2) the presence of a thin layer of oil deposits on the tube wall.
Since the propagation speed of the detonation wave far exceeds the speed of sound, the mechanism of flame propagation does not consider the heat transferred by heat conduction or the diffusion exchange between the combustion product and the fresh gas. In the detonation wave, the continuous combustion of the gas in each pipe section causes the adiabatic compression and compression of the shock wave. In the air compressor, the oil deposits in the air compressor are not only spontaneous combustion or even explosion accidents, but also a large amount of production, 2 toxic gases will Workers who directly injure pneumatic machinery.
Ginseng literature 1 Russia. Polichkov. Explosion of the compressor unit. Beijing Coal Industry Publishing
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