What is the function of an alkylation unit?

The function of an alkylation unit is to combine smaller hydrocarbon molecules, typically light alkenes, with isobutane to produce larger, branched alkyl compounds. These branched alkyl compounds are crucial because they serve as high-octane components for gasoline, enhancing fuel performance and reducing engine knock. The process involves the use of an acid catalyst and operates under specific conditions to promote the reaction between the feed components effectively.

In contrast, separating crude oil into lighter fractions is the primary function of a distillation column, not alkylation. Removing impurities from gasoline is generally handled by processes such as hydrotreating or refining, while heating crude oil prior to distillation is a preparatory step to ensure efficient separation, but it doesn't involve the alkylation unit. Hence, the role of alkylation distinctly centers on creating valuable gasoline components through the combination of smaller hydrocarbons into larger, branched molecules.