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Many chemical plants experience explosions following leaks; there are no sources of fire in the vicinity, and the plants are grounded to prevent static electricity. So, what could be the source of ignition?
Since an explosion can occur, it means that the conditions necessary for an explosion are met. Material leakage satisfies the condition of having an explosive mixture; a source of fire acts as the trigger for the explosion. Without a source of fire, an explosion cannot take place. There are many different types of sources of fire, and some materials have a very low ignition energy, around a few millijoules. In a chemical plant, there are certainly many such heat sources. This is my personal understanding for reference only!
Reply to 1# Yuhu: Haha, the original poster’s view is a bit ridiculous! Firstly, a combustion explosion occurs, which necessarily means that the three elements required for such an explosion are present. Secondly, just because static electricity is grounded does not mean that the requirements have been met; when there is a leakage, there is inevitably a lot of friction and impact, which can generate significant amounts of static electricity. Even if the static electricity is well grounded, it may not be possible to discharge it in time. And even if there are points where grounding is available for discharge, it doesn’t mean that the static electricity can be discharged in other uncontrolled areas... There are many possibilities in such situations.
Do you mean that static electricity is the more likely possibility?
Let me give you an example, owner: the hydrogen we use in our equipment is supplied by another factory. There were communication issues at that time; when the hydrogen was delivered, the drain valve on one of the hydrogen pressure gauges here was open, and the pressure of the hydrogen arriving was around 5 MPa. This caused hydrogen to leak from the pressure gauge drain and catch fire. In fact, hydrogen usually catches fire when released at high speed in situ, and the reason was explained very professionally above. The ignition energy of hydrogen seems to be 0.19 millijoules (which is very low); the high flow rate leads to friction, generating static electricity, and it’s normal for heat to be produced as a result
Reply to 4# Yuhu: It’s not necessarily static electricity; the reason was already explained on floor 2, but at least the possibility of static electricity is quite high!
I have experienced the situation described on the fifth floor: high-pressure hydrogen leaks that cause immediate combustion, as well as cases where hot oil from hydrogenation units led to combustion. I just want to confirm whether the ignition source was spontaneous combustion due to high temperature or ignition caused by static electricity Also, I would like to ask whether ethylene, propylene, and liquefied gas have similar flammability.
Reply to 1# Yuhu: Such phenomena can occur when the temperature is higher than the flash point, or when the leakage rate exceeds the safe flow rate.
It seems the original poster doesn’t have a clear understanding of what a fire source is! Sources of ignition can include open flames and temperatures that can cause ignition; high-temperature equipment in the vicinity, as well as electrical equipment that does not meet explosion-proof standards, can also serve as sources of ignition!
Anything is possible, says Li Ning. It’s not the case that accidents won’t occur just because all preventive measures have been taken. It’s difficult to predict what might happen – there’s static electricity, as mentioned earlier, as well as explosion-proof electrical equipment; there are also accidental impacts, and then there’s the release of energy stored within the materials themselves. All we can do is try to consider all possible accidents and take effective measures to prevent them from happening in the first place
Without a heat source and static electricity, there will be no combustion or explosion. The question then becomes a false proposition. All three elements of combustion are essential. The so-called lack of a heat source and static electricity might mean it wasn’t analyzed properly