Separation synthesis of multicomponent feed streams into multicomponent product streams

Abstract

The synthesis problem of separation sequences that separate several multicomponent feed streams into several desired multicomponent product streams is addressed. A superstructure is proposed for this separation problem that has embedded all the alternative separation configurations of interest. This superstructure, which has as separator units the separation tasks that are defined for each separation breakpoint, involves options for series and/or parallel sequences, as well as stream splitting, mixing, and bypassing. Formulating and solving this superstructure as a nonlinear programming problem that has as unknowns the stream interconnections, results in an optimal separation sequence. This sequence, which may involve fewer separator units than those included in the superstructure, is shown to be a realistic and practical one. The synthesis approach is illustrated with four example problems.

Mass/heat‐exchange network representation of distillation networks

“…These superstructures contain many design alternatives and can be used to obtain locally optimal configurations via MINLP programming techniques (Papoulias and Grossmann, 1983a,b,c;Grossmann, 1985;Duran and Grossmann, 1986;Floudas, 1987). Some unsuccessful attempts were made to identify global optima of these types of process synthesis problems.…”

Heuristic approach for the synthesis of heat-integrated distillation sequences

“…This example is taken from Floudas (1987). This example consists of one four-component feed stream that has to be separated into two four-component products by non-sharp separators.…”

“…The algorithmic approaches require complex optimization computer programs and involve many mathematical manipulations. Recently, several publications have addressed the synthesis problem for distillation sequence involving non-sharp separations (Wehe and Westerberg, 1987;Floudas, 1987;Bamopoulos et al, 1988;Chang and Liu, 1988;Muraki and Hayakawa, 1988;Aggarwal and Floudas, 1990;Liu et al, 1990;Chen and Fan, 1993;and Liu and Xu, 1995). These contributions did not consider heat integration.…”

Optimal Synthesis of Energy Efficient Distillation Columns Sequence Using Driving Force Method

“…Besides heuristic, optimization methods can be used to find efficient distillation sequence (Floudas, 1987;Wehe & Westerberg, 1987). According to (Floudas, 1987), all possible configurations of separation tasks will be embedded through superstructure which is used to extract the desired sequence by a nonlinear programming problem.…”

“…According to (Floudas, 1987), all possible configurations of separation tasks will be embedded through superstructure which is used to extract the desired sequence by a nonlinear programming problem. To produce multicomponent products from a single multicomponent feed through minimum number of columns using a nonsharp separation sequence, a bounding procedure could be used (Wehe & Westerberg, 1990).…”