: Classification of Crude Oil based on chemical composition
Elemental Composition of Crude Oils
Classification of Petroleum Hydrocarbons: Aromatics, Naphthenes, and Paraffins
Aromatics
Aromatic petroleum derivatives have a benzene ring type chemical structure. They are also known as polycyclic aromatic hydrocarbons (PAHs). Aromatics exhibit some chemical behaviors of benzene such as higher reactivity and higher solvency when compared to paraffinic and naphthenic products. The reactive nature of aromatic base oils makes them useful as petrochemical building blocks. They can be used to produce synthetic fluids and other petrochemical compounds. Naphthalene can be considered the simplest aromatic hydrocarbon, but is often classified to its own group.
Naphthenes
Naphthenic fluids have a high proportion of cycloalkane structures with an absence or very low wax molecule content (low to no alkanes). Mineral oils with less than 55 to 60% alkanes or paraffinic structures are considered naphthenic. Naphthenic, as well as aromatic, fluids have higher solvency than paraffinic fluids. Naphthenic fluids also exhibit better low temperature properties than paraffinic fluids, making them useful for low pour point applications.
Paraffins
Paraffin is an alkane hydrocarbon with the general formula (CnH2n+2). Paraffin or paraffinic petroleum derivatives include paraffin oils and paraffin wax. Paraffin wax consists of alkane mixture where chain length ranges from 20 ≤ n ≤ 40 range. The hydrocarbon chains are found in both straight and branched forms. Paraffin wax is solid at room temperature and begins to enter the liquid phase past approximately 37 °C (99 °F). Paraffin oil, like mineral oil, is a by-product from the petroleum distillation process. Paraffin based products are relatively non-reactive and have excellent oxidation stability. Paraffinic oils have relatively high wax content, high pour point, and typically a high viscosity index (VI).
Aromatics
Aromatic petroleum derivatives have a benzene ring type chemical structure. They are also known as polycyclic aromatic hydrocarbons (PAHs). Aromatics exhibit some chemical behaviors of benzene such as higher reactivity and higher solvency when compared to paraffinic and naphthenic products. The reactive nature of aromatic base oils makes them useful as petrochemical building blocks. They can be used to produce synthetic fluids and other petrochemical compounds. Naphthalene can be considered the simplest aromatic hydrocarbon, but is often classified to its own group.
Naphthenes
Naphthenic fluids have a high proportion of cycloalkane structures with an absence or very low wax molecule content (low to no alkanes). Mineral oils with less than 55 to 60% alkanes or paraffinic structures are considered naphthenic. Naphthenic, as well as aromatic, fluids have higher solvency than paraffinic fluids. Naphthenic fluids also exhibit better low temperature properties than paraffinic fluids, making them useful for low pour point applications.
Paraffins
Paraffin is an alkane hydrocarbon with the general formula (CnH2n+2). Paraffin or paraffinic petroleum derivatives include paraffin oils and paraffin wax. Paraffin wax consists of alkane mixture where chain length ranges from 20 ≤ n ≤ 40 range. The hydrocarbon chains are found in both straight and branched forms. Paraffin wax is solid at room temperature and begins to enter the liquid phase past approximately 37 °C (99 °F). Paraffin oil, like mineral oil, is a by-product from the petroleum distillation process. Paraffin based products are relatively non-reactive and have excellent oxidation stability. Paraffinic oils have relatively high wax content, high pour point, and typically a high viscosity index (VI).
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The Ternary Diagram
The image provided is a ternary diagram, a graphical tool used to show the proportions of three components that add up to 100%. In this case, the vertices represent 100% of each hydrocarbon type:
For example, a crude oil located near the paraffin vertex would be paraffinic-rich, while one near the center would have a more balanced composition. The diagram also correlates composition with other properties like sulfur content and viscosity.
Age and Depth Classification
The diagram also incorporates a classification based on the geological age and depth of the oil reservoir. This is because maturation (the process of converting organic matter into oil) influences the final chemical composition.
Old/Deep: These are the most mature crude oils. They are typically rich in paraffins, have the lowest sulfur content (sweet), and are the least viscous, with a lighter color. This type of oil is highly valued in the refining industry.
The image provided is a ternary diagram, a graphical tool used to show the proportions of three components that add up to 100%. In this case, the vertices represent 100% of each hydrocarbon type:
- The top corner represents 100% aromatics.
- The bottom-left corner represents 100% paraffins.
- The bottom-right corner represents 100% naphthenes.
For example, a crude oil located near the paraffin vertex would be paraffinic-rich, while one near the center would have a more balanced composition. The diagram also correlates composition with other properties like sulfur content and viscosity.
Age and Depth Classification
The diagram also incorporates a classification based on the geological age and depth of the oil reservoir. This is because maturation (the process of converting organic matter into oil) influences the final chemical composition.
- Young/Shallow: These oils are often less mature and tend to be rich in aromatics and naphthenes. They have a higher sulfur content (sour) and are more viscous.
- Young/Deep: These oils have undergone more thermal maturation. They have a moderate sulfur content and are less viscous than their shallow counterparts.
- Old/Shallow: These oils are generally more mature than young oils and have a lower sulfur content and viscosity.
Old/Deep: These are the most mature crude oils. They are typically rich in paraffins, have the lowest sulfur content (sweet), and are the least viscous, with a lighter color. This type of oil is highly valued in the refining industry.
References:
Elemental Analysis and Ternary Classification of Crude Oils | FSC 432: Petroleum Refining
Petroleum and Mineral Oil Products Selection Guide: Types, Features, Applications | GlobalSpec
Ternary diagram showing the classes of studied crude oil samples in the... | Download Scientific Diagram
Lubrita.com - Glossary of Tribology terms
Classification of Crude Oil
ความรู้พื้นฐานเกี่ยวกับน้ำมันหล่อลื่นอุตสาหกรรม ชนิดของ Based oil และ Additive
Elemental Analysis and Ternary Classification of Crude Oils | FSC 432: Petroleum Refining
Petroleum and Mineral Oil Products Selection Guide: Types, Features, Applications | GlobalSpec
Ternary diagram showing the classes of studied crude oil samples in the... | Download Scientific Diagram
Lubrita.com - Glossary of Tribology terms
Classification of Crude Oil
ความรู้พื้นฐานเกี่ยวกับน้ำมันหล่อลื่นอุตสาหกรรม ชนิดของ Based oil และ Additive
