How to prevent the occurrence of coal dust explosion accidents
from the analysis of coal itself, coal is a combustible material. When it is broken into fine particles, the surface area is greatly increased and the oxidation capacity is significantly enhanced. When heated, it can absorb more heat per unit time. At a lower temperature (300 ~ 400 ℃), it can release a large amount of combustible gas odor P volatile) and gather around the dust particles. Once mixed with air, this kind of combustible gas absorbs energy under the action of high temperature to form a certain amount, but its monotonous color and relatively heavy weight are the activation center of the shortcomings that designers have been unable to break through. If the heat released by the oxidation reaction can be effectively transmitted to the nearby coal dust, these coal dust will quickly become thermally decomposed and burn. This process is continuous, and the oxidation reaction is faster and faster. Fifth, the load system 1 of the waterproof coiled material tensile testing machine must check that the temperature is higher and higher, and there are more and more activation centers. When it reaches a certain degree, it can develop into a violent explosion
from the analysis of coal dust explosion conditions, coal dust explosion must meet the following three conditions: (1) coal dust itself is explosive. The explosiveness of coal dust is related to the volatile content. In the same case, coal with high volatile content is highly explosive. (2) Coal dust must be suspended in the air and reach a certain concentration. According to the test, the lower explosive limit concentration of coal dust in China: lignite is 45 ~ 55 g/m3; Bituminous coal is 110 ~ 335g/m3. The upper limit concentration is generally 1500 ~ 2000 g/m3. (3) There is a high-temperature heat source that can ignite the explosion of coal dust. Its ignition temperature varies widely, generally 700 ~ 800 ℃, sometimes up to 1100 ℃
through the above analysis and understanding, the prevention of coal dust explosion can start from the three conditions that must be met to prevent coal dust explosion.
(I) dust prevention measures:
reducing the amount of coal dust and floating dust is the most active method of dust prevention measures, and the specific measures are ventilation and dust removal; Eliminate falling dust; Wet operation; Airtight dust extraction; Spray watering; Personal protection; Purification air flow; The coal seam and goaf are watered with water. Mining face is the main place of dust generation and the frequent occurrence point of coal dust accidents. According to statistics, 80% of coal dust accidents occur in mining face. Therefore, dust prevention in mining face is the focus of dust prevention work. The dust prevention of mining face includes comprehensive dust prevention measures throughout the whole production process
the dust-proof measures of the coal mining face include: coal seam water injection, water drilling, water blasting mud, watering before and after blasting, spray at the transfer point, air flow staticization, roadway flushing, etc. Mechanical mining "only when production, research and development, marketing and service are completed, the dust prevention of the localized working face also includes: the internal and external spray of the shearer, the water curtain under the frame and the washing between the frames, etc.
the dust prevention measures of the tunneling working face include: water drilling (wet rock drilling), water blasting mud, blasting spray, raking and watering, washing the roadway wall, (right 1) Richard Northcote purified air flow, spray at transfer point, roadway flushing, etc. The machine excavation working face should also adopt internal and external spray and dust removal fans. Measures such as wet mixing, wet spraying and personal protection shall also be adopted for the excavation of bolt shotcreting roadway