INTRODUCTION

The Chevron Lummus Global (CLG) Residuum Desulfurization (RDS) and Vacuum Residuum Desulfurization (VRDS) Hydrotreating processes are used by refiners to produce low-sulfur fuel oils, and to prepare feeds for vacuum gas oil (VGO) fluid catalytic crackers (FCCs), residuum FCCs (RFCCs), visbreakers, and delayed cokers. Over half of the fixed-bed residuum hydrotreaters in operation use CLG s RDS/VRDS Hydrotreating technology.

RDS/VRDS Hydrotreaters upgrade residual oils by removing impurities and cracking heavy molecules in the feed to produce lighter product oils. Early applications of CLG s residuum hydroprocessing technology were used to remove sulfur from atmospheric residues (ARs) and vacuum residues (VRs), hence the term desulfurization. Today, RDS/VRDS Hydrotreaters perform equally well removing nitrogen, carbon residue (see Process Chemistry section), nickel, and vanadium from the oil and cracking heavy VR molecules to VGO, distillates, and naphtha products. The amount of impurities removed depends on the feed and on the product specifications desired by the refiner. Sulfur removal greater than 95 percent, metal removal (primarily nickel and vanadium) greater than 98 percent, nitrogen removal greater than 70 percent, carbon residue reduction greater than 70 percent, and cracking of vacuum...