Changes

==Crude oil Composition==

==Crude oil Composition==

Crude oil consists of four classes (SARA):

Crude oil consists of four classes (SARA):

#Saturates: Linear or branched chains of hydrocarbons with only single bonds connecting the atoms (also called alkanes). (e.g. Propane and Iso-butane).<ref name="3Paraffins">Eser, S., [https://www.e-education.psu.edu/fsc432/content/paraffins Paraffins]: Penn State course FSC432, [https://www.e-education.psu.edu/fsc432/ Petroleum processing].</ref>

* Saturates: Linear or branched chains of hydrocarbons with only single bonds connecting the atoms (also called alkanes). (e.g. Propane and Iso-butane).<ref name="3Paraffins">Eser, S., [https://www.e-education.psu.edu/fsc432/content/paraffins Paraffins]: Penn State course FSC432, [https://www.e-education.psu.edu/fsc432/ Petroleum processing].</ref>

#Aromatics: Chemical geometry contains of at least one unsaturated hydrocarbon cyclic with single and double bonds in alternating order (e.g. Benzene and Toluene).<ref name="4Aromatic Hydrocarbons">Eser, S., [https://www.e-education.psu.edu/fsc432/content/aromatic-hydrocarbons Aromatic hydrocarbons]: Penn State course FSC432, [https://www.e-education.psu.edu/fsc432/ Petroleum processing].</ref>

* Aromatics: Chemical geometry contains of at least one unsaturated hydrocarbon cyclic with single and double bonds in alternating order (e.g. Benzene and Toluene).<ref name="4Aromatic Hydrocarbons">Eser, S., [https://www.e-education.psu.edu/fsc432/content/aromatic-hydrocarbons Aromatic hydrocarbons]: Penn State course FSC432, [https://www.e-education.psu.edu/fsc432/ Petroleum processing].</ref>

#Resins: Are similar in terms of composition to asphaltenes but different in terms of percentage of presence of atoms relative to each other (i.e. H/C ratio is higher in resins than in asphaltenes).<ref name="5Speight">Speight, J. G., 2004, [https://ogst.ifpenergiesnouvelles.fr/articles/ogst/pdf/2004/05/speight1_vol59n5.pdf Petroleum asphaltenes: Part 1: Asphaltenes, resins and the structure of petroleum]: Oil & Gas Science and Technology – Rev. IFP, v. 59, no. 5, p. 467–477.</ref>

* Resins: Are similar in terms of composition to asphaltenes but different in terms of percentage of presence of atoms relative to each other (i.e. H/C ratio is higher in resins than in asphaltenes).<ref name="5Speight">Speight, J. G., 2004, [https://ogst.ifpenergiesnouvelles.fr/articles/ogst/pdf/2004/05/speight1_vol59n5.pdf Petroleum asphaltenes: Part 1: Asphaltenes, resins and the structure of petroleum]: Oil & Gas Science and Technology – Rev. IFP, v. 59, no. 5, p. 467–477.</ref>

#Asphaltenes: Is more complex organic compounds that are considered as the heaviest and most polar constituent in crude oil. Asphaltenes consist from Carbon, Hydrogen, Sulfur, Nitrogen, Oxygen, Vanadium and Nickle (e.g. phenols, fatty acids, esters and porphyrins).<ref name="5Speight" />

* Asphaltenes: Is more complex organic compounds that are considered as the heaviest and most polar constituent in crude oil. Asphaltenes consist from Carbon, Hydrogen, Sulfur, Nitrogen, Oxygen, Vanadium and Nickle (e.g. phenols, fatty acids, esters and porphyrins).<ref name="5Speight" />

Alkanes are generally biodegraded faster than aromatics.  This is because aromatics requires more energy to be consumed than alkanes. Furthermore, high molecular weight molecules are more difficult to be biodegraded than low molecular weight molecules.  

Alkanes are generally biodegraded faster than aromatics.  This is because aromatics requires more energy to be consumed than alkanes. Furthermore, high molecular weight molecules are more difficult to be biodegraded than low molecular weight molecules.

==How does biodegradation occur?==

==How does biodegradation occur?==