Whatever the country, petroleum refineries are never very numerous. Some countries do not even have any. In any case, taking the petroleum products directly from the refinery to the customer would be too complicated: it would require large numbers of road tankers covering enormous distances. The products therefore transit by intermediary storage centres, which are responsible for supplying a region: these are the petroleum depots.
These depots are also necessary for another reason: to meet possible interruptions in the supply chain, for example a halt in the supply of crude oil to the refinery or a drop in the output of finished products. In fact, the operators of the petroleum distribution network in many countries, including France, are responsible for maintaining stocks equivalent to 3 months of consumption, quantities known as strategic stocks.
The petroleum products are taken from the refineries to the depots by bulk transport methods: pipelines, trains of tanker wagons, river/canal barges, boats. Depot capacities are very variable, on average between 10 000 and 300 000 m3. The principal products stored are heating oil, petrol and diesel, as well as special diesel fuels used by farmers and fishermen, and aviation fuel.
A petroleum depot consists of 10 to 30 steel tanks. A tank can be as large as 60 000 m3. Each depot has 3 to 12 loading bays for the road tankers that will deliver the products to different consumers.
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| A hydrocarbon storage tank at the petroleum depot in le mans, with fire extinguishing system in the foreground. |
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In France, there are 60 or so main depots, belonging to the major petroleum operators. They supply filling stations and numerous secondary depots run by independent retailers. The road tankers used transport 10 to 30 tons of one or several products (in the latter case, the tankers are divided into compartments). |
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The products are regularly inspected throughout the whole distribution chain, from the refinery to the end user, to guarantee the maintenance of product quality and the absence of contamination by mixing.
In France, the petroleum operators must meet the demands imposed by a steady reduction in the number of depots: more than 300 depots of more than 400 m3 were closed between 1973 and 2001. |