Improving alkylation unit performance

摘要

One of the persistent challenges for refineries blending gasoline is achieving minimum octane ratings economically and without exceeding Reid vapor pressure (RVP) requirements. Some reformate products can do the job, but are expensive and reduce already thin margins. Adding butane helps raise octane, but can raise RVP beyond limits, particularly in the summer. One solution used in many refineries is adding alkylates made by combining lower-density products, typically olefins (mostly propylene and butene) with isobutene and isobutane. These feedstocks are inexpensive and available in sufficient quantities in many plants to make this approach practical and economical.