Crude Oil Storage
Crude Oil Storage
In almost all cases, crude oils have no inherent value without petroleum refining processes to convert them into marketable products. Crude oil is a complex mixture of hydrocarbons that also contains sulfur, nitrogen, heavy metals and salts. Most of these contaminants must be removed in part or total during the refining process. The hydrocarbons that make up crude oil have boiling points from less than 60˚F to greater than 1200˚F (60-650˚C).
Crude oil varies in sulfur content. Higher sulfur crude oil is more corrosive than lower sulfur crude oils. In order to process higher sulfur crude oils, equipment must be built from more expensive alloys to provide higher corrosion resistance. Many refineries are not able to process crude oils with high sulfur content.
The American Petroleum Institute (API) has developed a characterization for the density of crude oils:
- ˚API = (141.5/Specific Gravity@60˚F) -131.5
When comparing crude oils, the crude oil with the higher API will be easier to refine than one with a lower API.
Crude oil is delivered to a refinery by marine tanker, barge, pipeline, trucks and rail. The level of BS&W (bituminous sediment and water) is monitored to avoid high levels of water and solids. Water separates from crude oil as it sits in tanks waiting to be refined. This water is generally drained to waste water treatment just prior to processing.
