AM-93-54 COMMERCIAL OPERATIONS OF A DEMET UNIT

Description:

Coastal Refining and Marketing is operating a 20 TPD DEMETR unit that is directly attached to its 20,000 BPD FCCU. The activity and selectivity of the equilibrium catalyst in the FCCU were maintained at lower fresh catalyst make-up rates by recycling a 20 tons per day (TPD) slip-stream of catalyst from the FCCU regenerator through the DEMET unit and back to the regenerator. The fresh catalyst make-up to the FCCU was reduced from 4 TPD to 0.5 TPD and spent catalyst disposal was decreased by 3 TPD. ECAT additions remained at 2 TPD. The DEMET unit reduces the rate of accumulation of metals on the equilibrium catalyst so that less fresh catalyst is required to maintain activity and selectivity. Fresh catalyst make-up is always required to compensate for hydrothermal deactivation and attrition losses. The amount of fresh catalyst required depends on the FCCU design, FCCU operating conditions and the catalyst used. Any additional catalyst requirements resulting from metals poisons in the feed can be eliminated by using DEMET.