Robust Thermodynamically-guided Algorithms for Synthesis of Energy Efficient Separation Networks

摘要

Distillation has a particularly high potential for energy savings, as it accounts for aroundrn40-70% of capital and operating costs in petrochemical and commodity industries.rnHowever, numerous existing techniques that have been proposed to facilitate the designrnoften lack the robustness and reliability needed to rigorously solve the problem, largelyrndue to simplifying assumptions. In this contribution, we present computational methodsrnwhich exploit a novel thermodynamically motivated problem transformation, entitledrntemperature collocation, rather than using classical tray-by-tray models which fail inrnpinched regions. This novel methodology applies to ideal, non-ideal and azeotropicrnmixtures, and is independent of the number of components. Due to the generalisedrnnature of the method, we have also addressed the synthesis of complex columnrnconfigurations as well as heat integration of distillation trains. Furthermore, the robustrnsynthesis algorithm is presented, a method that automatically synthesizes a distillationrnnetwork for given product purity requirements. Entire separation flowsheets arerngenerated with rigorous thermodynamic models without the need to introduce limitingrnsimplifications as is the case with existing shortcut techniques. The computationalrnapproach guarantees to identify realizable columns with a finite number of trays andrnoperating conditions, which may easily be validated with industrial flowsheet simulatorrnsoftware packages like AspenPlus.