Distillation of Crude Oil

When crude oil is distilled, it is separated into different components known as fractions, each with its own unique properties and uses. The specific fractions that come out of a barrel of crude oil can depend on several factors, including the type of crude oil and the specific refining process used. However, the general process of distillation separates crude oil into the following fractions:

• Gases: This includes lighter gases such as methane, ethane, and propane, which are used as fuel, refrigerants, and raw materials for the chemical industry.
• Naphtha: A light liquid fraction that is used as a solvent, as a feed-stock for the production of gasoline, and as a starting material for the production of chemicals such as ethylene and propylene.
• Kerosene: A heavier liquid fraction that is commonly used as aviation turbine fuel, as well as for heating and lighting.
• Diesel: A heavier liquid fraction that is used as diesel fuel for vehicles, as well as for heating and power generation.
• Gas oil: A heavier liquid fraction that is used as a feed-stock for the production of diesel fuel and lubricating oils.
• Residuum: This is the heaviest fraction of crude oil and includes heavy liquids and solids. Residuum is used as a feed-stock for the production of asphalt, fuel oil, and other heavy products.

The specific percentages of each fraction that comes out of a barrel of crude oil can depend on several factors, including the type of crude oil, the refining process, and the intended use of the product. However, the general proportions of the different fractions that come out of a barrel of crude oil are as follows:

Gases: Typically, less than 10% of a barrel of crude oil. Naphtha: Typically, 5-10% of a barrel of crude oil. Kerosene: Typically, 10-15% of a barrel of crude oil. Diesel: Typically, 15-20% of a barrel of crude oil. Gasoil: Typically, 15-20% of a barrel of crude oil. Residuum: Typically, 50-60% of a barrel of crude oil.

There is no single "best" crude oil for refining, as the quality of crude oil depends on several factors, including its chemical composition, its source, and the intended use of the refined products. Typically, crude oils that are low in sulfur and heavy metals and high in lighter hydrocarbons, such as propane and butane, are considered to be of higher quality and more desirable for refining. Crude oils that are high in sulfur or heavy metals are generally considered to be of lower quality, as they are more difficult and expensive to refine into usable products.

The composition of a barrel of West Texas Intermediate (WTI) crude oil can vary, but on average it yields the following percentages of major distillate products:

• Gasoline: 35-40%
• Diesel: 20-30%
• Jet fuel: 5-15%
• Heating oil: 10-20%

Please note that these are rough estimates and the actual percentage of distillates produced from a barrel of WTI crude oil can vary based on factors such as the crude oil's composition, the specific refining processes used, and market conditions.That being said, the most desirable crude oil for refining depends on several factors, including:

• Refining capability: Different refineries have different capabilities and limitations, and some are better equipped to handle heavy, sour crude oils, while others are better suited to process lighter, sweeter crude oils.
• Market demand: The demand for different refined products, such as gasoline, diesel, and aviation fuels, can vary depending on market conditions, and the availability of crude oils that are well-suited for producing these products can impact their desirability.
• Location: The proximity of refineries to crude oil sources can also impact the quality of crude oil that is processed, as transporting heavy crude oils over long distances can be more expensive and logistically challenging.

Refining Process

The refining process is the series of steps used to convert crude oil into usable products, such as gasoline, diesel, and aviation fuels. The refining process typically involves the following steps:

• Pretreatment: Crude oil is typically heated and subjected to a series of treatments, including the removal of impurities such as sand, salts, and metals, to prepare it for further processing.
• Distillation: The crude oil is then heated in a distillation column, where it is separated into different fractions based on its boiling point. The different fractions are then collected and further processed into finished products.
• Conversion: Some of the heavier fractions, such as gas oil, are subjected to conversion processes, such as cracking or hydro-treating, to convert them into lighter products, such as gasoline and diesel.
• Purification: The different fractions are then subjected to additional purification processes, such as desulfurization and hydro-cracking, to remove impurities and improve the quality of the final products.
• Blending: Finally, the different fractions are blended to produce the finished products, such as gasoline, diesel, and aviation fuels. The blending process can involve the addition of various chemicals, such as octane boosters or diesel lubricants, to improve the performance and handling characteristics of the final products.

The specific steps involved in the refining process are much more detailed than the above, and they can vary depending on the type of crude oil being processed, the intended use of the final products, and the capabilities of the refining facility. The refining process is a complex and highly specialized operation that requires a combination of engineering, chemical, and operational expertise to ensure that the final products meet the necessary specifications and standards.