Commercial source of petroleum coke: Petroleum coke used by industry is predominantly produced by which refining process?

Introduction:
Petroleum coke (petcoke) is a solid carbonaceous by-product widely used for anodes and fuels. Multiple refinery units can produce minor coke, but commercial petcoke production is associated with a specific thermal cracking process that converts heavy residues into lighter products and solid carbon.

Given Data / Assumptions:

• Feed: vacuum residue or heavy resid streams.
• Objective: maximise distillate yield and produce solid coke as a by-product.
• Equipment options: visbreaker, FCC, hydrocracker, coker.

Concept / Approach:
Delayed coking thermally cracks heavy residues in drums at high temperature and moderate pressure, allowing coke to precipitate and build as the cracked vapours leave for fractionation. While FCC generates coke on catalyst (burned off during regeneration) and visbreaking limits overcracking to avoid excessive coke, the unit designed to intentionally produce bulk coke is the delayed coker.

Step-by-Step Solution:

Verification / Alternative check:
Refinery block flow diagrams show delayed coking routing vacuum residue to coke drums; product slabbing/cutting confirms commercial petcoke recovery.

Why Other Options Are Wrong:

• Hydrocracking: Uses hydrogen to avoid coke; target is distillates.
• Visbreaking: Mild thermal cracking aiming to reduce viscosity with minimal coke.
• FCC: Coke forms on catalyst and is burned in regenerator, not sold as product.
• Solvent deasphalting: Separates asphaltenes; not a coking process.

Common Pitfalls:
Equating any coke formation in a unit with commercial petcoke production; only coking drums produce sellable solid coke.

Final Answer:
Delayed coking