In recent years, dust explosions have mostly occurred in industries such as metallurgy, automobile manufacturing, military industry, coal, textiles, grain, and food and medicine. According to statistics, there is at least one dust explosion accident occurring on average every day worldwide. The Kunshan Zhongrong explosion accident that occurred on August 2, 2014 alone resulted in 146 deaths and 114 injuries, with serious consequences.
With the continuous development of modern industry, the number of enterprises involved in powder processing and dust generation is increasing. The vast majority of dust is flammable and carries an explosive risk. At the same time, many enterprise workshop equipment, pipelines, ceilings, and protective covers have serious dust accumulation, and the deposited dust will become the "dust source" of secondary dust explosions. Once a dust initial explosion accident occurs, the shock wave generated by the explosion will deposit dust oxygen, forming a dust cloud, resulting in a superimposed dust explosion accident.
Dust explosion accidents will generate high-temperature gases, forming high-speed and high-pressure shock waves, greatly threatening almost all production processes and assembly lines involving dust production enterprises. So, the severity of the consequences of dust explosions increases exponentially, and once they occur, they will cause roofs to flip, walls to collapse, and factories to be destroyed and people to die. Dust explosions pose a serious threat to industrial production safety and also makeDust explosion-proofTechnology has become a key technology for industrial safety.
The five elements of dust explosion:
1. There is combustible material. That is to say, there is combustible dust, such as starch, flour, etc. that are commonly found in our daily lives..
2. There are oxides that support combustion. Oxides not only refer to oxygen that supports combustion and explosion, but also include substances that can react chemically with combustibles.
3. Ignite the source. There are many types of ignition sources, such as open flames, static electricity, sparks, overheated surfaces, etc.
4. Confined space. Including various types of storage tanks, containers, houses, pipelines, etc.
5. Dust can suspend in the air. Dust is suspended in a closed container, and the concentration reaches the lower explosive limit. With the addition of the other four conditions, a dust explosion will occur.
Once a dust explosion occurs, it is not uncontrollable and there are many disaster control technologies available. The purpose of explosion disaster control technology is to control explosion accidents within the initial stage or local area of their occurrence, and to minimize the degree of damage and loss of the disaster as much as possible. In practical work, for dust explosions, it is necessary toExplosion proofThe perfect combination of technology, explosion venting technology, and explosion suppression technology is necessary to effectively control explosions.
1、 Explosion proof technology
When a dust explosion occurs, the flames and pressure generated will spread to other equipment and facilities through connected pipelines, conduits, conveyor belts, etc., causing a secondary explosion. In this case, explosion-proof technology can be used, and isolation equipment can be installed on the connected pipelines to prevent the spread of flames and eliminate the risk of secondary explosion.
Explosion proof equipment is divided into two types: mechanical and chemical. Mechanical explosion-proof devices are divided into active and passive types. Common passive isolation valves include Ventex valves, flap valves, etc. The working principle is that when an explosion occurs, the pressure generated by the explosion pushes the components in the valve body, isolating the valve. Active mode detects the occurrence of an explosion through a detector, and then sends a signal to the isolation equipment through a controller to actively close the valve. Active plug-in valves and chemical isolation belong to active isolation equipment.
2、 Explosion venting technology
Explosion relief technology is the process of opening and releasing pressure and flames during the explosion process by installing explosion relief plates and other equipment on the equipment, in order to avoid catastrophic damage to the process equipment. The area of the venting plate is related to the volume of the protected equipment and the explosive parameters of the material, which can be calculated using a formula.
When venting, the flames generated by the explosion, incompletely burned materials, and pressure will be discharged together. If the equipment is located outdoors, materials are allowed to be directly discharged into the atmosphere, and there is sufficient safety area around the equipment, direct venting can be chosen. If the equipment is located indoors and direct venting is not allowed, it can be vented outdoors through venting ducts. However, increasing the venting duct will increase the venting area and the maximum pressure reached by the venting. At this time, the venting can also be carried out through a flameless venting device, which extinguishes the flame during venting.
In summary, enterprises should choose the most suitable dust explosion protection technology based on their own process system and the explosive characteristics of dust.
In summary, based on the characteristics of dust explosion protection technology, in order to effectively control dust explosion accidents, enterprises must do a good job in the preliminary work, such as identifying the characteristics of dust sources, dust characteristics, diffusion characteristics, and the hazards of ignition sources, as well as specialized ventilation design. In response to the intensity of dust explosion and the rate of increase in explosion pressure, combined with the application of industrial dust explosion-proof technology, strengthen management and training, and achieve comprehensive and multi-level control of dust explosion accidents.
For more information on explosion-proof construction and renovation, please contact Zhongnuo Testing directly
Service hotline: 18924609560 (same WeChat account)
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