Supply and target based superstructure synthesis of heat and mass exchange networks

Abstract

This paper presents new methods for superstructure heat exchanger network synthesis (HENS) and mass exchanger network synthesis (MENS). The techniques developed in this study explore the use namely supply temperatures/compositions and target temperatures/ compositions in HENS and MENS to define the intervals of superstructures. Such superstructures are modelled as mixed integer non linear programmes (MINLP) with the objective of simultaneous minimisation of the total annual cost (TAC) of each network. The two superstructures presented in this paper are based on the supply based superstructure (SBS) developed previously [1]. The first uses the supply temperatures/compositions of hot/rich streams and the target temperatures/compositions of cold/lean streams, denoted supply and target based superstructure (S&TBS), while the second uses the target temperatures/compositions of hot/rich streams and the supply temperatures/compositions of cold/lean streams, denoted target and supply based superstructure (T&SBS). Three HEN examples and three MEN examples are presented, and the results obtained compare well with those in the literature.

A Numerical Tool for Simultaneous Targeting and Design of Mass Exchange Networks

“…Calculate the cumulative mass cascade Cascading is done from higher concentration to lower concentration in MENs because component is usually transferred from rich streams to lean streams. The cumulative mass cascade is calculated by using (5). The cumulative mass across a given composition interval, ΔM is obtained by adding the mass cascade at a higher composition interval Error!…”

“…Several techniques have been proposed to address this problem including mass pinch technology [1], heat and mass exchange networks [2], mathematical programming approaches [3] and batch MEN synthesis [4]. Azeez et al [5] proposed a new method by exploring key variables such as supply and target composition to define intervals of superstructure. This model is then formulated as mixed interval non-linear program (MINLP) with Total Annual Cost (TAC) minimization as the objective.…”