AM-95-18 CONTROLLING VANADIUM FROM HIGH METALS CRUDE OILS

Description:

Processing heavier high metals crude oils such as Maya and Venezuelan medium and heavy crudes continues to be an objective of many refiners. Processing requirements are more costly; however, with recent announcement of three(3) large joint venture projects to process high vanadium feedstocks the heavy crude volumes refined by U.S. refiners continues to increase. Refiners manage the vanadium and other contaminants with hydroprocessing’ and FCC catalysts that are more tolerant to metals. Although hydroprocessing and FCC catalyst formulations are critical and will be required for the bulk of the metals removal, many times primary distillation impacts on vanadium are ignored. Distillation system designs can significantly impact the metals content of the gas oil pool or the total gas yields for a targeted metals level. Commercial experience shows that total gas oil metals to the hydroprocessing unit can be reduced by 20 to 40 96 for a given gas yield or the total gas oil yield can be increased for a given metals target by optimizing primary distillation system performance. Total gas oil vanadium content has varied from 5 to 12 weight ppm depending on crude oil metals level, unit process design, distillation unit operation, and equipment design. An actual example using a 22.0 “API Bochequero Field(BCF) blend will be used to illustrate the points covered. The source of the vanadium in the various gas oil pool components will be evaluated and show potential gas oil quality improvements based on primary distillation system design and operation modifications. In our example, the refiner processes 145,000 bpd of crude oil through a conventional integrated atmospheric/vacuum unit and processes the vacuum residue in a delayed coker. The gas oil blend streams consists of atmospheric gas oil(AGO), light vacuum gas oil(LVGO), and heavy vacuum gas oil(HVG0) from the crude unit and heavy coker gas oil(HCG0) from the delayed coker. Figure 1 is a block diagram of the gas oil blend components. All the modifications which will be discussed have been operating successfully for several years.