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Coal dust explosion prevention technology

(1) coal dust explosion index. This index can be preliminarily determined by the combustible volatile content. In coal mine design, the combustible volatile content can be used as an index to determine the explosion risk of coal dust

(2) coal dust explosive identification. Although the coal dust explosion index can be used to determine its explosiveness, in view of the complexity of coal type and quality, the explosion index is only a preliminary judgment. In addition, the coal dust explosion identification test must be carried out in accordance with the provisions of the coal mine safety code. The national standard stipulates that the large tubular coal dust explosion identification device is used for the test, and the loading speed range is usually 0.001~20 in/Min (1in.=2.54cm) authorized units undertake the identification test

2. technical measures to prevent coal dust explosion

as mentioned above, coal dust explosion can occur only when three conditions are met at the same time. Different materials need different fixtures. If these conditions are not allowed to exist at the same time, or these conditions that have been formed are destroyed, take the initiative to calculate the actual parameters and output reports. More technical materials are available in Jinan Sida Testing Technology Co., Ltd, The occurrence and development of coal dust explosion can be prevented. This is the starting point and basic principle for formulating various measures to prevent coal dust explosion

(1) measures to prevent coal accumulation. Generally, the concentration of floating coal dust in production sites is far lower than the lower limit of coal dust explosion. However, due to air shock (blasting shock wave) and other reasons, the deposited coal dust flies again, and the coal dust concentration at this time greatly exceeds the lower explosion limit concentration. It is estimated that as long as a layer of coal dust with a thickness of 0.04mm is deposited on the periphery of the small roadway with a cross-section of 4m2, when it is all flying, it will reach the lower explosion limit. In fact, the coal dust deposited underground exceeds this thickness. Therefore, reducing the amount of coal dust deposited in the roadway and removing it out of the well is the simplest and effective explosion-proof measure

effective dust prevention and reduction measures are adopted in all production links to reduce the generation of coal dust, reduce the concentration of coal dust in the air, and reduce the amount of deposited coal dust. Therefore, comprehensive dust prevention measures are both measures to reduce dust hazards to workers' health. It is also a fundamental measure to prevent coal dust explosion

(2) eliminate ignition sources. Underground ignition sources that can cause coal dust explosion include electric sparks, friction sparks, friction heat, high temperature points formed by coal spontaneous combustion, deflagration caused by blasting and high temperature products produced by gas explosion. The main technical measures to eliminate such ignition sources include: maintaining the sound explosion-proof performance of mining electrical equipment, strengthening management to prevent the loss of explosion of electrical equipment, selecting non combustible light alloy materials to avoid dangerous friction sparks, conveyor belts, air ducts, cables and other common non-metallic materials must have flame retardant and antistatic properties, and using inhibitor, gel or nitrogen to prevent spontaneous combustion of coal pillars and residual coal in goaf. In addition to taking the above technical measures, we should also strengthen gas management to prevent the occurrence of gas explosion accidents

The products of the company are used in more than 60 high-speed railway projects such as Beijing Shanghai, Wuhan Guangzhou, Wenfu, Chengdu Mianyang Leshan, Shanghai Kunming, etc.

due to the complex natural conditions of coal mines, the randomness of coal dust explosion is very large. In addition to the above general safety technical measures, countries have also studied special technologies to prevent coal dust explosion according to the characteristics of coal dust explosion. Among them, the technical measure to prevent coal dust explosion, which has the longest history of use, wide application and is simple and easy, is the rock powder spreading method

(3) rock powder spreading method. This method is to regularly spread inert rock powder around the roadway and use it to cover the deposited coal dust deposited on the periphery of the roadway. When the wind speed of the roadway is very low, the viscosity of the rock powder layer plays a role in preventing the re flying of the deposited coal dust

when gas explosion and other abnormal conditions occur, the huge air turbulence wind blows up the rock powder and deposited coal dust to form a rock powder coal dust mixed dust cloud. When the explosion fire enters the mixed dust cloud area, the rock powder absorbs the heat of the flame to cool the system. At the same time, the rock powder particles will also play a shielding role to prevent the flame or burning coal particles from transferring heat to the unburned coal dust particles, and finally achieve the purpose of preventing the coal dust from catching fire. This method has been widely used in major coal producing countries such as Britain, the United States and Russia, and the effect is remarkable

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