Feasible region for a countercurrent cascade of vapor‐liquid CSTRS

Abstract

The attainable region approach for reaction-mixing systems was applied to systems with simultaneous reaction and separation. A model de®eloped for a countercurrent cascade of two-phase CSTRs can be considered as a surrogate for the stripping or rectifying sections of a reacti®e distillation column. An o®erall composition ®ector defined satisfies the same geometric properties as the reaction ®ector. The necessary conditions for the reaction-mixing attainable region were applied to the cascade of two-phase CSTRs. This article focuses only on the countercurrent cascade of two-phase CSTRs; therefore, the region identified is a feasible region, which is a subset of the attainable region for reaction-separation systems. For consecuti®e reactions, the boundary of the feasible region is gi®en by the trajectory for a cocurrent cascade of two-phase CSTRs. The o®erall composition ®ector for the cocurrent cascade of two-phase CSTRs is tangent to the trajectory. For single re®ersible reactions, the attainable region for single-phase reactors is significantly expanded by using a countercurrent cascade of ®apor-liquid CSTRs. Two examples used are transalkylation of toluene and the synthesis of isopropyl acetate.

Attainable regions of reactive distillation—Part III. Complex reaction scheme: Van de Vusse reaction

“…They solved the problem by a constrainted optimization technique (Feinberg and Ellison, 2001;Tang and Feinberg, 2007). The AR approach is further extended by others to reactive distillation systems for some specific cases (Nisoli et al, 1997;Gadewar et al 2002;Agarwal et al, 2008a), which provided momentum for setting ideal performance targets, and gave insight into the synthesis problem by means of graphical visualization. Nisoli et al (1997) formulated a systematic approach for reactorseparator models, viz.…”

“…The extension of this approach is proposed by Chadda et al (2001) to devise basic building blocks such as co-current and countercurrent rectifying or stripping cascades with liquid or vapor removal. Gadewar et al (2002) further developed the models for a cascade of vapor-liquid CSTRs, wherein, vapor and liquid flow counter-currently to each other. They showed that the AR analysis of conventional reactor network can be conveniently extended to the reactor-separator systems.…”

Attainable regions of reactive distillation—Part I. Single reactant non-azeotropic systems

“…It was further modified by Gadewar et al (2002) for the cascade of two phase CSTRs. The countercurrent cascade model of two phase CSTRs was considered as the surrogate for stripping and rectifying sections by Gadewar et al (2002).…”

“…It was further modified by Gadewar et al (2002) for the cascade of two phase CSTRs. The countercurrent cascade model of two phase CSTRs was considered as the surrogate for stripping and rectifying sections by Gadewar et al (2002). For the consecutive series reaction they showed that the suggested model offers enhanced selectivity when the reactant is heavier than the desired product.…”

Attainable regions of reactive distillation. Part II: Single reactant azeotropic systems

“…Attainable region approach first introduced by Horn (1964) has been extensively studied and developed by Hildebrandt and co-workers (Glasser et al, 1987;Hildebrandt and Glasser, 1990;Feinberg and Hildebrandt, 1997). Further extension to this approach for the systems with reaction and separation was presented by Nisoli et al (1997), Gadewar et al (2002), and Chadda et al (2001).…”