Context, issues and problems
Fuel depots can be found at many levels of our day-to-day life:
- large storage in refineries and the petrochemical industry,
- port storage of petroleum products,
- petroleum storage of industrial installations of all sizes for their energy requirements,
- final distribution networks (service stations over the entire territory).
The storage of petroleum products generally represents 2 main categories: flammable liquids and gases, including in particular liquefied combustible gases (LCGs). Only flammable liquids, with the exception of service stations, are tackled here. The special case of Liquefied Combustible Gases (LCG: butane, propane etc.) is tackled on the “gas depots” page.
- Fire and explosion: A fuel depot can be the cause of accidents due to the presence of flammable liquids whose combustion or explosion can be initiated, for example, by electrical installations. The most common accidents are retention pond fires and boil-over.
- Retention pond fire is the result of a ruptured tank or transfer pipe; flammable liquids then occupy the entire retention pond and the risk of ignition becomes significant. The thermal energy released is very high.
- Boil-over is a rarer but much more serious occurrence. If there is water at the bottom of a tank containing a heavy petroleum product and the tank catches fire, the water starts boiling after a few hours and pushes hydrocarbons above the tank, due to vapour thrust, thereby igniting the entire contents and generating a fireball.
- Water and soil pollution: in case of a hydrocarbon spill, by failure of the water-tightness of the retention pond, lack of resistance to the surge effect or lack of fire resistance of the walls or dikes.
- VOC emission: Loading and unloading operations cause hydrocarbon vapour discharge. These are VOCs (volatile organic compounds) which themselves are hazardous gases as well as ozone precursors.
- Vapour recovery is compulsory for loading / unloading petrol from wagons, trucks and river vessels (in accordance with precisely defined thresholds).