Flexibility Options for Absorption and Distillation to Adapt to Raw Material Supply and Product Demand Uncertainties: A Review

<jats:p>The chemical industry has to deal with increasing uncertainties regarding the boundary conditions of their production processes. On the one hand, uncertainties affect the availability, quality, and prizes of raw material and energy. On the other hand, the demand side is affected by increasing volatilities in product demand and increasing requirements for product variety. These changing boundary conditions lead to higher needs for flexibility in production processes of the chemical industry. Within this article technical solutions for an enhancement of different forms of flexibility are presented for production concepts and apparatus concepts, respectively. The latter focuses on unit operations for the separation of gas–liquid mixtures. This includes a review regarding transformable, modular production processes and a classification of their field of application. Additionally, concepts for named unit operations on different scales are presented and discussed. The presented concepts are also classified with respect to the different types of flexibility.</jats:p>