Synthesis of distillation sequences for separating multicomponent azeotropic mixtures

An automatic procedure for the synthesis of sequences of distillation columns for separating homogeneous multicomponent azeotropic mixtures is developed. Key to the approach is the use of sets of compositions, or ‘product regions’, to specify product compositions. The synthesis procedure is implemented in two stages. The first stage consists of identifying classes of splits. Each class of split may be characterised as either feasible or potentially feasible. The synthesis procedure systematically combines these classes of splits to generate column sequences that satisfy a pre-determined separation requirement. The second stage of the synthesis procedure assesses the feasibility of a proposed flowsheet once the recycle options have been defined. Preliminary design of each column in the sequence can be performed. The feasibility assessment procedure will form the basis for systematic flowsheet generation and optimisation.