Product

Straight-Run LPG is a liquefied petroleum gas fraction consisting primarily of propane (C₃) and butane (C₄) hydrocarbons that is recovered directly from the primary distillation of crude oil in the Atmospheric Distillation Unit (ADU), without undergoing any secondary conversion or cracking processes.

Key characteristics:

• Origin: Derived from the crude column overhead system (via the overhead accumulator, stabilizer, and gas recovery section), making it a "virgin" or "straight-run" stream—as opposed to cracked LPG, which comes from conversion units like FCC, hydrocracker, or coker.
• Composition: Predominantly saturated hydrocarbons—propane, propylene-free (or trace only), normal butane, and isobutane—since it has not been exposed to cracking reactions that produce olefins.
• Contaminants: Typically contains impurities requiring treatment, including hydrogen sulfide (H₂S), carbon dioxide (CO₂), mercaptans, and water, which are removed via amine treating, sweetening (e.g., Merox), and drying.
• End uses: After treatment, SR LPG is used as commercial/domestic LPG (cooking gas), as feedstock for steam crackers (for ethylene/propylene production), as alkylation unit feed (butanes), or blended into gasoline (butanes for vapor pressure control).

Distinction: Unlike cracked LPG, SR LPG is essentially olefin-free, making it a cleaner, preferred feedstock for steam cracking, since it avoids the diolefins and reactive olefins found in cracked streams that can cause coking and require selective hydrogenation before use.