Application of Hydrogen Sensors in Hydrogen Leakage and Explosion Accidents in Chemical Plants
Application of Hydrogen Sensors in Hydrogen Leakage and Explosion Accidents in Chemical Plants
A pipeline in the synthesis workshop of a chemical plant in Jiangsu Province suddenly ruptured, followed by a massive hydrogen leakage. The factory leaders immediately ordered the operators to close the main valve and auxiliary valves and shut down the entire plant for an emergency stop. About 5 minutes later, just as the relevant personnel were urgently discussing how to handle the accident, an explosion suddenly occurred in the synthesis workshop. In the explosion center area covering approximately over 1,000 square meters, the nearly 10-meter-high workshop building was blown to ruins. Hundreds of window panes in the nearby factory buildings were all shattered by the blast. The explosion caused 3 immediate deaths in the synthesis workshop, another 2 deaths due to ineffective rescue efforts for severe injuries, and 26 injuries.
In this accident, after the pipeline rupture led to a large-scale hydrogen leakage, the objective conditions for an explosion were already met. According to explosion theory, for a combustible gas to ignite and explode in the air, two essential conditions must be satisfied: First, the concentration of the mixture formed by the combustible gas and air must reach the explosion limits, creating an explosive gas mixture. After the pipeline ruptured, a large amount of hydrogen leaked out, immediately forming a flammable and explosive gas mixture that spread rapidly. The explosion limits of hydrogen in the air range from 4% to 75%, and detonation will occur when its concentration reaches 18.3% to 59%.
Second, there must be an ignition source capable of igniting the explosive gas mixture. When hydrogen gushed out in large quantities from the ruptured pipeline, intense friction occurred between the hydrogen and the pipeline rupture point, generating a high electrostatic voltage. When the static charge accumulates to a certain level, it will break down the air medium and discharge to the grounding body, producing electrostatic sparks that trigger the explosion.
The occurrence of this accident was mainly due to deficiencies in equipment and facility management, which failed to detect hidden pipeline hazards in a timely manner and carry out maintenance and replacement promptly. The following preventive measures should be implemented:
Effectively strengthen equipment management. Conduct regular technical analysis and systematic leak detection on pipelines, valves, and other components prone to corrosion and damage, and carry out thorough maintenance during the periodic major equipment overhaul.
Strictly prohibit open flames in the fire and explosion-proof zones of the plant. Personnel entering these zones shall wear anti-static clothing or pure cotton work clothes; the use of mobile phones and other communication devices is forbidden in these zones; all electrical facilities in the fire and explosion-proof zones, including lighting fixtures and switches, shall be explosion-proof, with well-insulated wires and secure joints; exposed hot objects are strictly prohibited in the fire and explosion-proof zones.
Strengthen training on relevant technical knowledge, enhance employees' awareness of the hazards associated with relevant equipment, establish and improve various rules and regulations, and earnestly implement relevant operating procedures.
Formulate emergency response plans and strengthen emergency drills to improve the ability of enterprise management personnel to handle emergencies. In this accident, timely evacuation of production personnel could have reduced casualties.
To better reduce such accidents, it is necessary to install H₂ sensors in chemical plants for real-time monitoring of hydrogen leakage. Shenzhen Wuliang Sensor Technology Co., Ltd. provides fast-response H₂ sensors as follows:
