sidestream

In petroleum refining, "sidestreams" refer to intermediate products drawn from various points within a fractional distillation column. These sidestreams represent fractions of crude oil that have boiling ranges between the lighter overhead products and the heavier products at the bottom of the column.1

For example, typical sidestreams include light naphtha, heavy naphtha, crude kerosene, and light gas oil, each with specific boiling ranges. These intermediate products are then sent for further processing in other refinery units, such as catalytic reformers or cracking units, to be converted into more desirable products. Superfractionation is an advanced distillation technique that uses more complex columns to isolate very narrow ranges of components or even pure compounds for specialized applications.12