Organometallic Compounds & Inorgarnic Salt
- Metallic Compounds
- Some of the more abundant are sodium, calcium, magnesium, aluminium, iron, vanadium, and nickel.
- They are present as inorganic salts;
- They are present in the form of organometallic compounds
- nickel and vanadium (as in porphyrins).
- Calcium and magnesium can form salts or soaps with carboxylic acids. These compounds act as emulsifiers, and their presence is undesirable. (Q: why their presence is undesirable?)
- Although metals in crudes are found in trace amounts, their presence is harmful and should be removed.
- Vanadium and nickel are poisons to many catalysts and should be reduced to very low levels. Most of the vanadium and nickel compounds are concentrated in the heavy residues. Solvent extraction processes are used to reduce the concentration of heavy metals in petroleum residues.
// Properties of Crude Oil
Crude oils differ appreciably in their properties according to origin and the ratio of the different components in the mixture.
- Lighter crudes generally yield more valuable light and middle distillates and are sold at higher prices.
- Crudes containing a high percent of impurities, such as sulfur compounds, are less desirable than low-sulfur crudes because of their corrosivity and the extra treating cost.
- Corrosivity of crude oils is a functionof many parameters ;
- the type of sulfur compounds and their decomposition temperatures,
- other total acid number,
- other type of carboxylic and naphthenic acids in the crude and their decomposition temperatures.
- For a refiner, it is necessary to establish certain criteria to relate one crude to another to be able to assess crude quality and choose the best processing scheme