An Enhanced Stage-wise Superstructure for Heat Exchanger Networks Synthesis with New Options for Heaters and Coolers Placement

Abstract

Several methods for heat exchanger networks (HEN) design are based on the use of superstructures. The models they give rise to can lead to different design options to be explored in HEN synthesis. In this work, a stage-wise superstructure with new features for the optimal placement of heaters and coolers, including the possibility of the use of multiple utilities, is presented. In the model, those units can be placed in different stream split branches in all stages, differing from the usual allocation at stream ends. Such possibilities yield a more complex mathematical model. To solve it, an improved version of a previously presented hybrid meta-heuristic method was used. Three examples from the literature were studied. The use of the superstructure with the additional utility-related options, as well as the enhanced meta-heuristic solution method, led to configurations with lower associated total annual costs than those reported in previous works.

An extended method for work and heat integration considering practical operating constraints

“…where [32] and is an enhancement in comparison to the original stage-wise superstructure of Yee and Grossmann [3]. The calculation of heat loads for those units are performed via energy balances, whose derivation may be found in detail in the published literature [31,32].…”

“…A matrix-based representation was proposed for matching the work and the heat recovery stages. The latter employs an enhanced HEN superstructure model [32]. Moreover, the scheme utilized a meta-heuristic method for the solution.…”

“…Aiming at more realistic solutions, the method developed in the present work attempts to consider the aforementioned constraints more rigorously. The main methodology innovations regard: (i) novel programming routines were implemented into unit blocks for attaining these practical configurations taking as a basis the master structure of our previous framework [32]. The main change is that these blocks use temperatures rather than shaft-work as decision variables, which makes the solution method considerably more efficient in finding solutions with units operating within narrower, industrial-like temperature ranges.…”

Heat Exchanger Network Synthesis Integrated with Compression–Absorption Cascade Refrigeration System

“…In recent years, the original stage-wise superstructure proposed by Yee and Grossmann [3] has been improved and perfected. Such as the assumption of isothermal mixing was shattered [4], and the superstructure was enhanced to contain more possibilities [5], as well as to consider the parallel connection of utilities in stream split branches [6] and series connection of utilities in substages [7].…”

Simultaneous Synthesis of Heat Exchanger Networks Considering Steam Supply and Various Steam Heater Locations

“…The problem can be solved faster, but many possible matches are not included in the proposed superstructure because it was equivalent to a stage-wise superstructure with only one stage. Pavão et al [11] considered the solving difficulty of complex mathematical models resulting from an enhanced stage-wise superstructure which includes the use of multiple utilities at single stream branches. An enhanced meta-heuristic solution method was presented to handle the complex mathematical model, and the superstructure had no difference from the superstructure in Ponce et al [8] mentioned above.…”