Minimum energy demand for distillations with distributed components and side-product withdrawals

Köhler, Jürgen; Kuen, Thomas; Blaß, Eckhart

doi:10.1016/0009-2509(94)e0123-8

Cited by 22 publications

(16 citation statements)

References 9 publications

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“…The linear phenomenological equations that follow from Eq. (29) are where Jd (in m3 m-'h-') is the relative mass flux between heavy and light components across the interface (Jd = Jl/y, -Jh/y,,), Jh and Jl are the mass fluxes of heavy and light components, respectively, yh and yl are the compositions of heavy and light components, respectively, and the constant parameters, Lji, are the local phenomenological transport coefficient, which can be determined from experiments. For isothermal conditions, the phenomenological coefficients for mass transfer are …”

Section: Demirelmentioning

confidence: 99%

Thermodynamic Analysis of Separation Systems

Demi̇rel

2004

Separation Science and Technology

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Separation systems mainly involve interfacial mass and heat transfer as well as mixing. Distillation is a major separation system by means of heat supplied from a higher temperature level at the reboiler and rejected in the condenser at a lower temperature level. Therefore, it resembles a heat engine producing a separation work with a rather low efficiency. Lost work (energy) in separation systems is due to irreversible processes of heat, mass transfer, and mixing, and is directly related to entropy production according to the Gouy-Stodola principle. In many separation systems of absorption, desorption, extraction, and membrane separation, the major irreversibility is the mass transfer process. In the last 30 years or so, thermodynamic analysis had become popular in evaluating the efficiency of separation systems. Thermodynamic analysis emphasizes the 3898Demirel use of the second law of thermodynamics beside the first law. and may be applied through (i) the pinch analysis, (ii) the exergy analysis. and (iii) the equipartition principle. The pinch analysis aims a better integration of a process with its utilities. It is one of the mostly accepted and utilized methods in reducing energy cost. Exergy analysis describes the maximum available work when a form of energy is converted reversibly to a reference system in equilibrium with the environmental conditions; hence, it can relate the impact of energy utilization to the environmental degradation. On the other hand. the equipartition principle states that a separation operation would be optimum for a specified set of fluxes and a given transfcr area when the thermodynamic driving forces are uniformly distributed in space and time. Thermodynamic analysis aims at identifying. quantifying, and minimizing irreversibilities in a separation system. This study presents an overview of the conventional approaches and the thermodynamic analysis to reduce energy cost, thermodynamic cost. and ecological cost in separation systems with the main emphasis on distillation operations. Some case studies of cost reduction based on the thermodynamic analysis are also included.

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Section: Demirelmentioning

confidence: 99%

Thermodynamic Analysis of Separation Systems

Demi̇rel

2004

Separation Science and Technology

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“…With the exception of two articles Ž . published recently by Kohler et al 1994 andRooks et al Ž . 1996 , which we will discuss in some more detail below, all the techniques proposed previously constitute generalizations Ž .…”

Section: Columns With a Sidestreammentioning

confidence: 96%

“…Ž . Kohler et al 1994 proposed a minimum reflux method for sidestream columns and nonideal or azeotropic mixtures Ž . based on the minimum-angle criterion MAC .…”

Section: Columns With a Sidestreammentioning

confidence: 99%

Shortcut methods for nonideal multicomponent distillation: 2. Complex columns

1999

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“…[4][5][6]17 Many relevant contributions to construct product pinch point curves have been done. 8,9,16,18,19 Aguirre and Espinosa 20 presented a rigorous algorithm based on imbedding homotopic continuation methods.…”

Section: Subscripts and Superscriptsmentioning

confidence: 99%

Optimal Synthesis of Multicomponent Zeotropic Distillation Processes. 1. Preprocessing Phase and Rigorous Optimization for a Single Unit

Barttfeld

Aguirre

2002

Ind. Eng. Chem. Res.

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Separations performed by distillation involve large operation costs due to either large heat loads or large amounts of solvent used in azeotropic mixtures. Thermodynamic aspects helpfully lead the process synthesis to energetically efficient designs. The reversible distillation sequence model (RDSM) is employed in this work as a theoretical and ideal thermodynamic model. The aim of the paper is to present an automatic methodology for the synthesis of simple distillation columns that approximate reversible conditions. A preprocessing phase is considered where proper values to initialize and bound the variables involved in the rigorous model are calculated by successively solving auxiliary optimization models. In all cases studied, the solutions obtained are very similar to those in the so-called reversible separation. This fact is used as a test criterion for global optimality of the solutions.

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Minimum energy demand for distillations with distributed components and side-product withdrawals

Cited by 22 publications

References 9 publications

Thermodynamic Analysis of Separation Systems

Thermodynamic Analysis of Separation Systems

Shortcut methods for nonideal multicomponent distillation: 2. Complex columns

Optimal Synthesis of Multicomponent Zeotropic Distillation Processes. 1. Preprocessing Phase and Rigorous Optimization for a Single Unit

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