Demetallization of Crude Oil with Emphasizing on Biotechnological Strategies

Oil is a mixture of hydrocarbons containing a variety of organic compounds and heavy metals. The presence of vanadium and nickel in crude oil has an adverse effect on the refinery processes and acts as a poison on catalysts used in catalytic cracking, hydrogenation and hydro-desulphurization processes. This leads to a significant decrease in the yield of cracked products. Metals in crude oil increase the production of coke and gases and cause a marked shortening in the catalyst’s life. The process involving the oxidation of sulphur dioxide to sulphur trioxide is catalyzed by vanadium in fuel oil combustion, leading to corrosion and formation of acid rain. Among strategies for removing metals from crude oil, chemical processes such as solvent extraction, catalytic and catalytic hydroprocessing have been commonly used because of their effectiveness. These are often expensive and produce secondary pollution in the environment. In recent years, due to advantage of the biological methods rather than other methods, more studies have been carried out regarding to biorefinery. This paper reviews the recent trends about demetallizating of heavy metals from crude oil with insisting on biological methods.