Analysis and preventive measures of explosion acci

Analysis of gas boiler explosion accident and preventive measures

(1) extraordinarily serious accident:

the main pressure parts in the boiler - drum, tubesheet, etc. have rupture and explosion accidents, which often lead to equipment, plant damage, personal casualties and heavy losses

(2) major accidents:

accidents in which the gas-fired boiler cannot maintain normal operation and is forced to shut down, such as water shortage accidents, furnace explosion accidents, etc. Although this kind of accident is not as serious as a major accident, it often causes equipment and plant damage and personal casualties, and forces the gas-fired boiler to stop operation (rise/fall rate), resulting in partial or total shutdown of the steam department, resulting in serious economic losses

(3) general accidents:

accidents that can be eliminated during operation or accidents that can be eliminated after a short shutdown have less impact and loss. The gas boiler accident belongs to the explosion accident that causes the largest loss among the three main types of industrial thermal disasters. There are two main causes of explosion, one is furnace explosion, the other is furnace explosion. Gas fired boilers have a high frequency of explosion accidents

2. Fire hazard analysis of gas-fired boilers

2.1 dangerous characteristics of gas

the fuel of gas-fired boilers is combustible gas, mainly natural gas or gas. The main component of natural gas and coal gas is methane, mixed with some simple alkanes. These components are highly flammable and explosive gases. The lower explosion limit of natural gas is 4%, and that of coal gas is 4.2%, which is very prone to explosion accidents

2.2 fire hazard of furnace explosion

furnace explosion is due to the leakage of combustible gas and mixing with air to form an explosive mixture. When this mixture is within the explosion limit, an explosion accident will occur as soon as it comes into contact with an appropriate ignition source

with chemical changes, the gas pressure in the furnace increases instantaneously, and the explosive force generated exceeds the structural strength, causing an outward explosion. Due to the accumulation of a large amount of energy in a limited volume in a very short time, the boiler furnace is in an unusual high-pressure or high-temperature state, causing the surrounding medium to vibrate or the adjacent substances to be damaged

furnace explosion is mainly caused by the following factors

2.2.1 improper ignition of electrical equipment and materials

during ignition, if the ignition operation is improper, the gas source is not cut off in time, the gas distribution pipe is not purged with combustible gas, or the purging is not complete, the nozzle does not ignite or is blown out when the valve is opened, or the accuracy of experimental data may cause a large amount of high concentration combustible gas to accumulate in the furnace and be within the explosion limit, When igniting again, these combustible gases will be ignited, causing an explosion

2.2.2 the flame is unstable and goes out

if the output of a single component or two-component waterproof material burner prepared by gas is too large, the flame will disengage from the burner and the phenomenon of de ignition will occur; On the contrary, if the output is too small, the flame will retract into the burner, backfire will occur, and the flame will be unstable and extinguished during the boiler operation. Because the furnace is in a hot state, it will reach or exceed the ignition temperature of the mixture of combustible gas and air, and when the combustible gas continues to enter, there may be an immediate explosion

2.2.3 because the valve leaks, the equipment is imperfect, and there is no ignition and fire extinguishing protection device and flame detection device, the combustible gas fills the furnace and ignites and explodes

2.2.4 leakage of gas transmission pipeline

due to the huge gas transmission pipeline of gas-fired boiler, the consumption of combustible gas is large, and some pipelines have been aging and corroded. If you do not pay attention to the maintenance and overhaul of pipelines, combustible gas leakage is likely to occur in the process of gas transmission, resulting in explosion accidents

2.2.5 operational errors

some accidents can be avoided when the boiler is running, but the accidents still occur. The main reasons are that the operators operate irrationally when the boiler is running, do not operate in accordance with the rules and regulations, the staff have insufficient safety awareness, do not work responsibly, and the shift and maintenance are not carried out in accordance with the regulations, which eventually leads to the occurrence of accidents