Types of Distillation Column Residue:

1. Atmospheric Residue (AR):
   • Product of crude oil distillation at atmospheric pressure.
   • Boiling point above approximately 350–400°C.
   • Contains heavy and viscous compounds.
2. Vacuum Residue (VR):
   • Product of vacuum distillation of atmospheric residue.
   • Has higher molecular weight and more complex compounds compared to atmospheric residue.

Physical and Chemical Properties

• Appearance:Black, thick, and highly viscous substance.
• Main Components:Polycyclic aromatic hydrocarbons (PAHs), asphaltenes, resins, and sulfur.
• Boiling Point:Above 500°C (depending on distillation type).
• Density:Higher than crude oil; usually between 0.9 to 1.1 g/cm³.
• Viscosity:Very high, especially at low temperatures.

Applications of Atmospheric Residue

• Industrial Fuel:Used as fuel for furnaces, boilers, and industrial units.
• Feedstock for Downstream Processes:Used to produce more valuable products such as gasoline, diesel, and lubricating oils through processes like Fluid Catalytic Cracking (FCC), thermal cracking, and coking.
• Asphalt Production:One of the main raw materials for bitumen and asphalt production due to its high asphaltene content.
• Petrochemical Feedstock:Used to produce specific petrochemical products such as carbon black and certain chemicals.
• Petroleum Coke Production:Converted to petroleum coke in the coking process, which is used in the steel and aluminum industries.

Advantages

• Reusability:Atmospheric residue can serve as feedstock for further refining and petrochemical processes.
• High Added Value:With proper processing, more valuable products can be produced from it.

Disadvantages

• High Impurities:Contains significant amounts of sulfur, heavy metals (such as vanadium and nickel), and complex compounds, which reduce fuel quality and cause environmental issues.
• High Density and Viscosity:Requires heating or special handling for transportation and use.
• Environmental Pollution:Direct burning produces pollutants such as sulfur oxides and particulates.

Common Processing Techniques for Atmospheric Residue

• Fluid Catalytic Cracking (FCC):Converts atmospheric residue into lighter products such as gasoline and diesel.
• Coking:Produces petroleum coke as the final product.
• Hydrocracking:Reduces the molecular weight of the residue to produce lighter hydrocarbons.
• Asphalt Production:Utilizes the heavy fractions for making bitumen and asphalt.