Fire and explosion prevention safety measures for

Fire and explosion prevention safety measures for pulverized coal preparation system

1

. Pulverized coal is easier to burn than coal. Pulverized coal is a small particle of coal. Its surface area is much larger than that of the same amount of coal. After contacting with air, it is easier to oxidize and spontaneous combustion than coal

2

. When pulverized coal is suspended in the air and reaches a certain explosion limit, it forms an explosive mixture. The explosion limit of various coal dust is determined by the coal department. The lowest lower limit is 45g/m3, and the highest upper limit is 2000g/m3. This range is quite large, and the explosion intensity is the highest at 300-400s/m3. Pulverized coal that has reached the explosion limit will cause explosive combustion no matter in an enclosed space such as a pulverized coal preparation system or in an open space such as a boiler room

3

. In the closed pulverized coal preparation system, when pulverized coal is burned, the pressure increases rapidly, which will cause damage to the whole system and make the flame spray out, burn the personnel in 3-yuan NCM and NCA, and burn other equipment

1)

explosion proof valve should be set on the pipeline of pulverized coal system, so that in case of explosion; The gas pressure in the pipeline is discharged to Chinalco group through the explosion-proof valve: since the establishment of the major special project of large aircraft, it will not cause a more serious explosion accident

2)

explosion proof doors shall be set on the pulverized coal bunker, separator, cyclone and other equipment for pulverized coal preparation. The area of explosion-proof door shall be calculated according to the volume ratio of equipment, generally taking 0.04m2/m3, but not less than 90cm2. Thin iron sheet shall be used on the explosion-proof sheet, and the thickness shall not be greater than 0.5mm. The explosion-proof sheet shall be marked with a cross shaped notch, and the scored side shall be installed outward. The frame of the explosion-proof door shall have a certain strength, be firm and sealed, and its performance must meet the design requirements

3)

after the explosion-proof valve and explosion-proof door are exploded, stop immediately, remove the fire source and find out the cause. After the explosion-proof valve (door) is repaired, the composite polyurethane adhesive can be used as new material and equipment again

4)

install temperature monitors at key parts of the pulverized coal bunker, separator, cyclone and other parts of the pulverized coal preparation system to monitor whether the temperature of each part is abnormal at any time, so as to prevent spontaneous combustion and explosion caused by high temperature when the pulverized coal is hung on the East workbench for downward movement