Any liquid hydrocarbon mixture occurring naturally in the earth. Properties of crude oil vary considerably depending upon its origin. Crudes generally have a flash point below 26.7°C and a Reid vapour pressure from about 42 to 84kPa. Crude oils have contaminants such as sulphur and vanadium compounds which encourage corrosion of steel. Crude oils with high and low sulphur contents are referred to as “sour” and “sweet” crude oils respectively.
- Heavy crude – Crude oil with a high percentage of heavy oil fractions.
- Light crude – Crude oil which contains a high proportion of lighter fractions and is particularly suitable for gasoline production.