Fixed-bed residuum desulfurization technologies—RDS for atmospheric residuum and VRDS for vacuum residuum—provide a short, economical process path to higher-value products from difficult feeds. These hydrogen-efficient processes sufficiently saturate products so that further processing in conversion units is greatly enhanced, ultimately producing more and higher-value light products.
Adding an Onstream Catalyst Replacement (OCR) unit enables refiners to significantly increase capacity or improve product quality from the RDS unit. With the ability to replace spent catalyst on-line, refiners can increase feed throughput, process heavier feeds with higher levels of contaminant metals, or achieve deeper desulfurization when processing low-metal feeds as compared to a standard RDS unit. In either retrofit or grassroots installations, the investment cost for an OCR reactor and catalyst transfer equipment is more than offset by the savings realized in crude cost and in improved catalyst efficiency.