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Control Practice in FCC Operation: Philosophical Discussion and Looking into the Future

Presented By

Mel Larson - KBC


Maximum capacity definitions are different today than they were 10 years ago. The FCCU continues to be one of the key economic drivers for refinery profitability. The crude diet or basket of crudes for a refiner are more dynamic and changing from West Canadian Select, to Tight Oil, blended with some Middle east or LATAM crude source. This increases the potential variability of feed with operations that remain within the current regulatory boundaries. What margins are used today on constraints that define a reliable operating window?

Some companies constantly push their CatCracker unit to maximum capacity. That increases their output, but also increases the risk of an event (upset or atmosphere release) and takes its toll on equipment reliability.

What do you get if you back away from pushing that limit? What do you make now running at 100% with “mistakes” vs running at a lower safer rate that is finely tuned with fewer issues? How do you calculate or justify a longer and safer run at a lower capacity vs the lost throughput at max capacity?

You have to consider releases because they are now included in the operating permit envelope. What is the current and future considerations of thermal cycling of the unit? Are there key pieces of equipment to consider like cyclones and refractory, main air blower, and wet gas compressor cycling? Is there a safe operating window or distance from the maximum capacity for your CatCracker that is lower than flat out which has now become the new norm? This presentation will discuss the risk/reward ratio of running at sustainable capacity that may yield higher revenue value for the refinery.

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