Optimal Mixing for Exothermic Reversible Reactions
01 May 1992-Industrial & Engineering Chemistry Research (American Chemical Society)-Vol. 31, Iss: 6, pp 1541-1549
TL;DR: In this paper, a geometrically-based approach for determining the attainable region of a single exothermic reversible reaction was proposed. But the results were applied to an extensively investigated example and shown to give an improved value of the objective function.
Abstract: Recently developed geometrically-based ideas for determining the attainable region have been applied to single exothermic reversible reactions where the only processes allowed are preheating a portion of the feed, reaction, and mixing. The following system of reactors in series in general defines the boundary of the attainable region: a CSTR, a plug flow reactor, a differential reactor which does not in general follow the optimal temperature profile, and finally another plug flow reactor. Analytical conditions have been derived for the operating parameters of these reactors. This system of reactors gives a limit against which other reactors which use only the above-mentioned processes can be compared; for example a cold-shot-cooling reactor. This new approach combines several previous results into a cohesive theory. The ideas are applied to an extensively investigated example and shown to give an improved value of the objective function
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TL;DR: This paper takes advantage of attainable-region properties derived from geometric targeting techniques to design a concise reactor module for reactor network synthesis, formulated as a compact mixed integer nonlinear program.
Abstract: The reactor is the most influential unit operation in many chemical processes. Reaction systems and reactor design often determine the character of the flowsheet. However, research in reactor network synthesis has met with limited success because of nonlinear reaction models, uncertain rate laws, and numerous possible reactor types and networks. In this paper we take advantage of attainable-region properties derived from geometric targeting techniques to design a concise reactor module for reactor network synthesis. The reactor module is made up of a continuous stirred tank reactor and a plug flow reactor (for two dimensional targeting) or a differential sidestream reactor (for higher dimensions). These modules are used to synthesize the optimal reactor network target with respect to a specific objective function, and the problem is formulated as a compact mixed integer nonlinear program. This new algorithm overcomes many of the drawbacks of existing algorithms. Finally, we solve several example problems ...
104 citations
TL;DR: In this article, a two-level stochastic optimization approach is proposed to target the performance of chemical reactors with the use of stochastically optimized configurations. But it is not restricted by the dimensionality or the size of the problem.
Abstract: A systematic methodology to target the performance of chemical reactors with the use of stochastic optimization is presented. The approach employs a two-level strategy where targets are followed by the proposition of reactor configurations that match or are near the desired performance. The targets can be used for synthesis and retrofit problems, as they can provide the incentives to modify the operation, and ideas in developing the reactor design. The application of stochastic optimization enables confidence in the optimization results, can afford particularly nonlinear reactor models, and is not restricted by the dimensionality or the size of the problem.
60 citations
TL;DR: In this paper, the Attainable Region method is used to synthesize both chemical reactors and more general systems, by using geometric ideas to define the allowable processes as vectors in a space of the basic variables of the problem.
51 citations
TL;DR: In this article, the authors propose linear programming (LP) models for attainable region (AR) analysis by considering a rate vector field in concentration space with an arbitrarily large number of points, and demonstrate these proposed linear programming techniques on several two-dimensional reaction mechanisms and then apply the LP methods to verify extensions for a previously published three-dimensional candidate AR.
51 citations
TL;DR: In this paper, a profile-based optimization method for the synthesis of nonisothermal reactor networks is proposed, which concentrates on targets rather than network details, and the results illustrate ways to avoid unnecessarily complicated networks and develop simpler and transparent designs.
Abstract: A new optimization method for the synthesis of nonisothermal reactor networks offers major challenges concerning the lack of robustness in the existing methods and the numerous local and near-optimal solutions that characterize these problems. The approach offers a reliable and widely tested methodology that upholds a profile-based search. The search concentrates on targets rather than network details. The results illustrate ways to avoid unnecessarily complicated networks and develop simpler and transparent designs. The single-phase examples explain merits over past studies and other conventional synthesis methods. Multiphase examples are presented for the first time in the literature, as well as results from an industrial example.
50 citations