Excellence in refining is dynamic. When external conditions change, as they inevitably will, refiners need to adapt to ensure that their mode of operation continues to be relevant. And when they do, a revamp project can often be key to ensuring a cost-effective response, as an initiative at a Shell refinery demonstrates.
The hydrocracker was originally designed by Shell in the 1980s as a full-conversion unit with a two-stage configuration geared towards middle distillate production. In response to growing demand for middle distillates, the unit’s capacity was later increased to about 167% of the design capacity, though it still operated as a two-stage unit.
However, increasing demand for petrochemicals and an enhanced petrochemical margin provided the triggers that led to Shell changing the hydrocracker’s mode of operation.
To increase its petrochemicals capacity, the company intended to build an ethylene cracker in the adjacent petrochemicals plant, so it commissioned Shell Global Solutions to help plan the investment and to understand and evaluate its technical and operational options.
It was during this review that Shell Global Solutions’ strategic planners identified that the economics of the refinery and the petrochemicals site could be greatly enhanced by adapting the hydrocracker to produce large amounts of unconverted oil (hydrowax), which could be used as ethylene cracker feedstock.