disengaging definition
disengaging term used here means that this is the point at which the catalyst is no longer borne by the nitrogen; it is “disengaged” or separated from the nitrogen transportation medium. Approximately 5-10 pounds of fines are expected to be removed daily and sent for offsite reclamation. The catalyst is cooled to 250-300F in the disengaging hopper, and is then dropped into the regenerator. The regenerator has three zones, identified as the diluted air zone, the oxychlorination zone, and the drying zone. Approximately 0.07 mol% oxygen is reacted with the catalyst to begin coke burn-off in the diluted air zone. The low oxygen content and the name of the zone are derived from diluting air with nitrogen. The catalyst then drops to the oxychlorination zone, where it is reacted with air and perchloroethylene (perc), which conditions the catalyst by redistributing the metal on the catalyst. Air is blown across the catalyst in the drying zone to remove any remaining moisture. The regenerated catalyst exits the bottom of the regenerator and is moved with hydrogen to the reduction zone above the top of the first reactor. At this point it is further regenerated by contact with additional hydrogen, which combines with excess oxygen to create water vapor. During reactor operation, chloride is injected into the reactor to help maintain catalyst activity. The regenerator tower vents back through the disengaging hopper, allowing the sulfur and chloride in the regenerator vent gas to be absorbed by the catalyst entering the regenerator. This reabsorption process is known as Chlorisorb. Platforming produces hydrogen that is then used by the NHDS, DHTU, SCAN, and PENEX units for desulfurization of their feedstocks, although some of the hydrogen is retained or recycled in the reactors to prevent the reaction from cracking the naphtha. The CCR had first operations on December 11, 2007.