Concentration of Various Contaminants
In addition to hydrocarbons, crude oil contains hetroatom (S, N, metals) species that need to be removed if their concentrations are higher than the specified thresholds. Other impurities in crude oil include salt and sediment and water. The acidity of crude oil is also important, particularly for concerns of corrosion in pipes or other process units. Carbon residue of a crude oil indicates the tendency to generate coke on heter tubes or rector surfaces. All of these contaminants and properties of crude oils are measured using standard methods, as described in this section.