To prevent gas explosion, we should mainly start from two aspects: preventing gas accumulation and eliminating fire sources.

1. Measures to prevent gas accumulation

(1) Strengthen ventilation. Reduce the gas concentration to below the concentration specified in the "Coal Mine Safety Regulations", that is, the intake air flow of the mining face does not exceed 0.5%, the return air does not exceed 1%, and the total return air of the mine does not exceed 0.75%.

(2) Strengthen inspection work. It is an important content of daily gas management to timely check the ventilation status and gas concentration of each wind-using place and find hidden dangers to deal with. The methane detection instruments used in China in 1980s are: optical methane detector, thermal methane detector, methane alarm and methane telemetering alarm. After 1990s, more advanced TX series intelligent mobile gas monitors and telemeters began to be used.

(3) For high gas coal seam, gas drainage should be carried out to reduce the gas emission from coal seam and goaf.

2. Measures to prevent gas fire

(1) Open flame is prohibited within 20m around wellhead house, gas drainage station and main ventilation room.

(2) Safety lighting should be adopted in gas mines. It is forbidden to turn on miner's lamps underground, and it is forbidden to carry tobacco and ignition tools underground.

(3) Strictly manage the underground fire area.

(4) Strictly implement the shooting system.

(5) Strictly manage the regional ventilators in the heading face, and the regional ventilators shall be equipped with wind power locking devices.

(6) The electrical devices in gas mines shall comply with the provisions of "Coal Mine Safety Regulations" on explosion-proof efficiency.

(7) With the improvement of mining mechanization, it is more and more important to prevent mechanical friction sparks from igniting gas. Gas explosion accidents caused by friction sparks account for a considerable proportion in coal mines, so many countries have studied this problem and put forward that a layer of low-activity metal (such as chromium) should be plated on the metal surface of friction parts so that friction sparks can not ignite gas; Various coatings are coated on the surface of aluminum alloy to prevent the occurrence of friction sparks, and a small amount of beryllium is added to the metal to reduce the flammability of friction sparks.

What are the technical measures to prevent gas explosion?

Technical measures to prevent gas explosion mainly include three aspects: (1) preventing gas accumulation. The so-called gas accumulation refers to the phenomenon that the regional gas concentration exceeds 2% and the volume exceeds 0.5 cubic meters. In order to prevent gas accumulation, each mine must try to avoid blind alleys from the management of production technology, and the temporary shutdown site is not allowed to stop the wind, and strengthen the management of ventilation system, strictly implement the gas inspection system, and timely and safely handle the accumulated gas. 2 to prevent gas ignition. The measures to prevent gas from catching fire are to prohibit and put an end to all fire sources; Strictly manage and control possible fire sources and heat sources in production to prevent them from generating or limiting their ability to ignite gas. Therefore, it is forbidden to bring tobacco and ignition materials into the well; Miner's lamp shall be in good condition, otherwise it shall not be distributed, and disassembly, knocking and impact are strictly prohibited; Strengthen the management and maintenance of electrical equipment, adopt explosion-proof electrical devices, provide underground power supply without chicken feet, sheep tails and joints, and adhere to the comprehensive protection of coal electric drills; Adhere to the use of wind power locking local ventilator. (3) Prevent gas explosion from expanding.

Under what circumstances will a gas explosion occur? How can we prevent it?

Gas explosion must meet the following three basic conditions:

(1) a certain gas concentration. In fresh air, the explosion limit of gas is generally 5%~ 16%. When the gas concentration is lower than 5%, it will not explode in case of fire, but it can form a combustion layer around the flame. When the gas concentration is 9.5%, the explosion power is the largest; When the gas concentration is above 16%, it loses its explosiveness, but it will still burn when it meets fire in the air.

(2) Ignition temperature. The ignition temperature of gas is generally considered to be 650~ 750℃.

(3) The oxygen content is sufficient. Oxygen concentration shall not be lower than 12%.

Gas explosion accidents can be prevented. Preventing gas explosion is to eliminate the conditions of gas explosion and limit the spread of explosion flame to other areas. To sum up, there are three main aspects: preventing gas accumulation, preventing gas explosion and preventing the expansion of gas explosion accidents.

Under the action of high-temperature fire source, gas reacts with oxygen to generate carbon dioxide and water, and gives off a lot of heat, which can make carbon dioxide and water vapor generated in the reaction process expand rapidly, form high temperature and high pressure, and rush out at a very high speed, resulting in a dynamic phenomenon, which is gas explosion. Its harm is mainly manifested in the instantaneous high temperature, high pressure, high-speed shock wave and toxic and harmful gases produced by the explosion.

What safety measures should be taken in coal mines to prevent gas explosion?

There are three necessary conditions for gas explosion: gas concentration, ignition source and oxygen concentration.

1. Prevent gas accumulation

2. Prevent the occurrence of fire sources

3. Strengthen gas inspection and monitoring.

In fact, it is mainly to control the gas concentration and ignition source underground so that it does not meet the conditions of gas explosion.

How to avoid gas explosion in coal mining process

We know that gas explosion must meet three conditions: 1, a certain gas concentration (5%-16%); 2. High temperature fire source for ignition (650℃-750℃); 3, enough oxygen content (more than 12%), these three conditions must be met at the same time, gas explosion is possible. However, in the actual production process of coal mines, the third condition has always existed. To put an end to gas explosion, efforts must be made from two aspects: putting an end to high-temperature fire sources and controlling gas concentration. It is necessary to strengthen management from the following aspects: building a reasonable ventilation system, carrying out gas extraction, strengthening monitoring, preventing gas accumulation, strengthening regional ventilation management, putting an end to the explosion loss of electromechanical equipment, putting an end to underground open flames, strengthening goaf management, and improving fire pipeline system.