A strong explosion in Rome in a petrol and LPG distributor caused a big fire. When it comes to fuels fossils, one of the most common is the LPGthat is, the liquefied oil gas. It is a mixture of propane (c3H8), Butano (C4H10) inside which there are also small percentages of other hydrocarbons such as etano, propylene or IsoButano. This fuel is produced by oil refining and to room temperature is presented to the gaseous state. Usually for transport it comes Liquefied: This allows you to transport it and stood it in a much easier way, and from here the adjective “liquefy“In the name. Unfortunately the recent news events have focused the spotlight on one of its particular feature, that is, theflammability. But from a technical point of view, why it can carey and even get to cause Explosions? Before continuing with the explanation, it is good to keep in mind that that of the explosion is an eventuality extremely rare And, as we will see, whoever owns a LPG car can be calm.
What is LPG and how flammable is
LPG (Liquefied Oil Gas) is a mixture of hydrocarbons (mainly butane and propane) used as fuel. The first thing to keep in mind is that the LPG it is more dense than the airand therefore tends to stagnate downwards and not to disperse. The second important factor is the fact that, as happens for methane, if there is one right relationship between gas and airin case of trigger it is possible that his combustion occurs. This concentration of gas in the air, called flammability limitis rather low for the LPG and goes from About 2 to 9%. This means that if in the air there is a concentration of LPG between these two values (which can still slightly vary according to the local conditions) a combustion can occur in the presence of a trigger.
From a chemical point of view, the combustion of LPG in the presence of air within certain values is linked to the reaction between the molecules that make up the fuel (propane and butane) with the molecular oxygen present in the air. This chemical reaction produces energy, but above all generates gases (as co2 and water vapor) that tend to expand by increasing the pressure.
If this reaction takes place in a confined environment, such as a tank, and safety systems do not work properly, the high presence of gas can grow the pressure to the point of causing a real explosion.
LPG and cars risks
So who has a LPG car should worry? The answer is nothere is no need to panic.
The LPG tanks present in our cars are equipped with systems security designed ad hoc To minimize the risk of fires and explosions. For example there is always one safety valve able to release the gas in case of surchargeor the same cylinder is made in such a way as to resist shocks and accidents without breaking. The fires and explosions caused by LPG in a car for this reason are very rare and can occur in the event of very serious accidents or systems installed by non -competent people or even from the use of free flames during the refueling phase.
At the same time it is good to keep in mind that the liquefied oil gas, like any fossil fuel, is still flammable: If it were not it could not be used inside an endothermic engine! For this reason it is necessary handle it carefully And it is also for this reason that in Italy its refueling cannot be done independently But only by a specialized operator.
