Gas boilers are boilers that use gas as fuel and are currently widely used. But the danger factor of this type of boiler is still relatively high, and if there are errors during use, it is easy to explode. What is the cause of gas boiler explosion? How should we avoid explosions in gas boilers.
Firstly, let's understand the structure of a gas boiler, which includes two systems: gas combustion equipment and boiler body. Gas combustion equipment mainly refers to the furnace and burner, as well as other equipment related to the combustion process. Its main function is to introduce a certain amount of combustible gas and air into the combustion equipment, convert chemical energy into thermal energy through the combustion of combustible gas, and provide continuous thermal energy to the boiler body. The boiler body utilizes the heat energy provided by combustion equipment to convert water into steam, making it a certain amount and quality (pressure and humidity) of steam. The entire boiler production process involves sending a certain amount of combustible gas and corresponding amount of air into the furnace for combustion. The heat generated by combustion is transferred to the water supply, causing the water to vaporize at a constant pressure and form water vapor at a certain pressure and temperature. If a gas boiler explodes, there are three possible scenarios:
(1) The main pressurized components in the boiler, such as the drum and tube plate, are prone to rupture and explosion accidents, which often lead to equipment and plant damage and personal injury, resulting in significant losses.
(2) Accidents where gas boilers are unable to maintain normal operation and are forced to shut down, such as water shortage accidents, furnace explosion accidents, etc. Although such accidents are not as serious as major accidents, they often cause damage to equipment and factories, as well as personal injury and death, and force gas boilers to shut down, resulting in partial or complete shutdown of the steam department and causing serious economic losses.
(3) Accidents that can be eliminated during operation or those that can be eliminated after a brief shutdown have relatively small impacts and losses.
Below, we will introduce the causes and treatment measures of gas boiler explosion. A furnace explosion is caused by the leakage of combustible gases and their mixing with air to form an explosive mixture. When this mixture is within the explosive limit range, it can cause an explosion accident when in contact with an appropriate ignition source. Accompanied by chemical changes, the gas pressure inside the furnace instantaneously increases sharply, generating an explosive force that exceeds the structural strength and causes an outward explosion. Due to the accumulation of a large amount of energy in a limited volume in a very short period of time, the boiler furnace is in an unusual high-pressure or high-temperature state, causing vibration of surrounding media or damage to adjacent substances. Furnace explosions are mainly caused by the following factors.
1. Improper ignition
During ignition, if the ignition operation is improper, and the gas source and distribution pipe are not cut off in a timely manner for combustible gas blowing, or the blowing is not thorough, the nozzle does not ignite or is blown out when the valve is opened, or other situations may cause a large amount of high concentration combustible gas to accumulate in the furnace and be within the explosion limit range, these combustible gases will be ignited again during ignition, causing an explosion.
2. The flame is unstable and extinguishes
If the output of the gas burner is too high, the flame will detach from the burner, causing a phenomenon of detachment; On the contrary, if the output is too small, the flame will retract into the burner, causing a backfire phenomenon, which makes the flame unstable and extinguished during boiler operation. Due to the hot state of the furnace, reaching or exceeding the ignition temperature of the combustible gas air mixture, and continuing to feed combustible gas, there is a possibility of immediate explosion.
3. Incomplete equipment
Due to valve leakage, incomplete equipment, lack of ignition and fire extinguishing protection devices and flame detection devices, combustible gas filled the furnace and ignited, resulting in an explosion.
4. Gas pipeline leakage
Due to the large size of gas transmission pipelines in gas boilers and the high consumption of combustible gases, some pipelines have already aged and corroded. If maintenance and repair of pipelines are not paid attention to, combustible gas leakage can easily occur during the gas transmission process, leading to explosion accidents.
5. Operational error
During boiler operation, some accidents can be avoided, but accidents still occur. The main reason is that the operators operate the boiler improperly, do not follow the rules and regulations, have insufficient safety awareness, are irresponsible in their work, and do not follow the regulations during duty and maintenance, ultimately leading to accidents.
The explosion of a gas boiler body is caused by factors such as poor material quality of boiler equipment, insufficient strength or severe water shortage of pressure components, and continuous heating.
1. In terms of design and manufacturing of gas boilers
Unreasonable design causing structural defects in gas boilers; The material does not meet the requirements; Rough welding quality; Insufficient strength of pressure components and other factors are also important factors causing gas boiler explosions.
2. Explosion caused by water being burned out in the boiler
During the operation of the boiler, the water inside will be gradually reduced by heating. When the water inside the boiler is too little or even burned out, the heat energy released by the combustion of combustible gases directly heats the boiler equipment itself, causing overheating of the furnace body and resulting in explosion accidents.
