What are “sweet” and “sour” Crude?
Sweet Crude has small amounts of sulphur (mainly in the form of hydrogen sulphide H2S) (0.5% or less) and carbon dioxide, and is used primarily in the production of petrol. Sulphur does damage to the equipment when refining and does damage to the environment (and your car’s engine) if not removed. If the percentage exceeds 0.5% it is classified as sour. Because of the costs involved in removing the sulphur, sour oil tends to be cheaper than sweet oil.
