Noun
English Wikipedia has an article on:unit operationWikipedia
unit operation (plural unit operations)
Any simple step in a multi-step chemical engineering process; examples include distillation, evaporation, mixing, filtration, crystallization etc.
Especially in the production of polymers, the gas separation by membranes has acquired increasing importance in the petrochemical industry and is now a relatively well-established unit operation. Source: Internet
Project engineering jobs are some of the largest employers for chemical engineers. citation Process design and analysis main A unit operation is a physical step in an individual chemical engineering process. Source: Internet