Delayed vs other coking processes in Indian refineries Which coking process is most widely used in Indian oil refineries for residue upgrading?

Introduction / Context:
Coking converts vacuum residue into lighter products and petroleum coke. Process selection depends on feed quality, product slate, and capital considerations. Understanding which process is dominant locally aids context for plant operations and exams.

Given Data / Assumptions:

• Indian refinery configuration commonly includes thermal conversion for heavy residues.
• We compare delayed, flexi-, fluid, and contact coking.

Concept / Approach:
Delayed coking is the industry workhorse worldwide, including in India, due to its relative simplicity, flexibility to handle diverse residues, and ability to produce marketable needle/sponge coke and valuable naphtha/gasoil. Fluid and flexicoking are specialized and less common, and contact coking is not typical in modern large-scale refineries.

Step-by-Step Solution:

Verification / Alternative check:
Public refinery configuration data and project reports show multiple delayed cokers commissioned or planned across India, confirming prevalence.

Why Other Options Are Wrong:

• Flexi-/fluid coking: Less common, higher complexity; specific licensors and fewer installations.
• Contact coking: Obsolete/rarely used industrially for large modern refineries.

Common Pitfalls:
Confusing fluid coking with fluid catalytic cracking; FCC is for VGO, not vacuum residue thermal coking.

Final Answer:
delayed