debutanizer

A debutanizer is a distillation column used in hydrocarbon processing to separate C4 components (butanes) from pentanes and heavier fractions in a C4+-rich feed. It is a standard unit in natural gas liquids (NGL) processing plants and in refinery fractionation trains, typically located downstream of a depropanizer or stabilizer. The feed to a debutanizer is usually a C4+-containing stream, and the column is operated with reflux to separate the lighter C4s from the heavier C5+ components.

The overhead product is a C4-rich stream, consisting mainly of n-butane and isobutane, with small amounts of impurities. The bottom product is C5+ and heavier hydrocarbons, which may be routed to further fractionation or to a storage or processing stream as appropriate for the plant configuration.

Applications and use: The C4 fraction obtained from the debutanizer is commonly used as refinery fuel gas or as a feedstock for petrochemical processes such as alkylation and isomerization. The C5+-rich bottom stream can be sent to additional fractionation steps, storage, or further processing depending on plant design. Debutanizers are designed with an appropriate number of trays or packing, reflux ratio, and operating conditions to achieve the desired separation while accommodating feed variability.

See also: Demethanizer, Depropanizer, Fractionation.