As discussed in Increasing Crude Flexibility, refiners can capture substantial value by increasing their crude flexibility. Meanwhile, a site’s residue conversion capability is becoming an increasingly important value driver, especially given the forthcoming changes to marine bunker fuels specifications that are examined in The Bunker Fuels Challenge: How should you respond? Consequently, ever more refiners are evaluating a solution that addresses these twin objectives: converting their residue desulphurisation unit to a deasphalted oil (DAO) hydrocracker so they can simultaneously increase crude flexibility and minimise fuel oil production.
Shell’s Pernis refinery in the Netherlands has taken a positive step to reduce its exposure to the forthcoming changes to bunker fuel sulphur specifications. By installing a new solvent deasphalting (SDA) unit and revamping its residue hydroprocessing unit to a DAO hydrocracker, the refinery will increase its conversion of fuel oil to distillates. Crucially, this will also increase its crude flexibility.
With a capacity of 404,000 bbl/d, Pernis refinery is the largest integrated refinery–petrochemicals manufacturing site in Europe and, with hydrocracking, fluidised catalytic cracking (FCC) and gasification units in its configuration, it has a high Nelson complexity index.
As shown in Figure 1, the plan at Pernis is to integrate the new SDA unit with a DAO hydrocracker and the gasification plant. This is a relatively low-cost way of reducing fuel oil production while also enabling processing of a wider range of lower-priced crude oils.
The new hydrocracker has a design feed of 100% DAO (extraction depth 60–70% on vacuum residue) derived from the main Pernis crude sources (Russia, the Middle East and Africa). It will operate at 65% conversion and produce ultra-low-sulphur-diesel and jet kerosene. The unconverted oil will go to the existing FCC unit. The hydrocracker will have a two-year cycle length.