Shortcut Design of Fully Thermally Coupled Distillation Systems with Postfractionator

Ruíz-Marín, Lorena E.; Ramírez‐Corona, Nelly; Castro-Agüero, Angel; Jiménez‐Gutiérrez, Arturo

doi:10.1021/ie102032e

Cited by 7 publications

(6 citation statements)

References 27 publications

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“…The authors report that the DDWC shows lower energy requirements than the DWC, for a mixture with a low concentration of the middle-boiling component. Ruiz-Marin et al 16 report that the use of a posfractionator (i.e., the second dividing wall) provides improvement over the Petlyuk column only for mixtures with an ESI value lower than 1. Goḿez-Castro et al 15 present a Pareto front of optimal solutions to the design and optimization problem of DWC and DDWC, reporting a strategy for the calculation of the required diameter for the DDWC, based on the distribution of the vapor flows.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Dynamic Performance for Multiple Dividing Wall Distillation Columns

Gómez‐Castro

Rodríguez-Ángeles

Segovia‐Hernández

et al. 2013

Ind. Eng. Chem. Res.

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Dividing wall columns are intensified process equipment with the capacity of reducing both capital and operational costs for a given vapor−liquid separation, when compared with conventional distillation sequences. For some kinds of mixtures, distillation systems with two dividing walls have been theoretically proved to present lower energy requirements and lower total annual costs than systems with a single dividing wall. Nevertheless, the use of an additional wall may lead to operational issues on the column, because of the more complex arrangement of the walls on the trays of the columns, where additional split of the vapor and liquid streams is expected. Thus, in this work the open-loop properties (minimum singular value and condition number) for the double dividing wall column are studied and compared with those of the dividing wall column for a wide range of frequencies, in order to determinate if the use of additional dividing walls may lead to potential control problems. It has been found that both systems show similar dynamic performance, with advantages for the double dividing wall column for mixtures with low composition of the middle-boiling component.

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Section: Introductionmentioning

confidence: 99%

Analysis of Dynamic Performance for Multiple Dividing Wall Distillation Columns

Gómez‐Castro

Rodríguez-Ángeles

Segovia‐Hernández

et al. 2013

Ind. Eng. Chem. Res.

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“…Mathematical‐programming‐based feed angle method (FAM) was developed by Kraemer et al and later reformulated by Skiborowski et al to superstructure‐based distillation network synthesis. Shortcut methods were also proposed for the design of reactive distillation columns, thermally coupled columns, and divided wall columns …”

Section: Introductionmentioning

confidence: 99%

From graphical to model‐based distillation column design: A McCabe‐Thiele‐inspired mathematical programming approach

Kong

Maravelias

2019

AIChE Journal

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We propose a mixed-integer nonlinear programming (MINLP) model for simple and complex distillation column design and optimization. The model is based upon the concepts and equations underpinning the McCabe-Thiele method. Generalizing this method, we introduce material balances at various locations of the column and employ binary variables to determine the optimal number of trays and optimal feed locations. We model the vapor-liquid equilibrium using continuous piecewise linear approximating functions. The model is extended to account for multicomponent mixtures and non-constant-molar overflow. We also discuss how to estimate the minimum number of trays and the minimum reflux ratio. 1 | INTRODUCTION Distillation is arguably the most important unit operation in the separation subsystem of chemical processes. The design and optimization of distillation columns have drawn considerable attention in the chemical engineering literature for more than 100 years. A simple yet accurate distillation model is crucial for higher-level modeling such as distillation sequencing, 1-9 separation network synthesis, 10,11 and general process synthesis. 12-14 Methods for modeling distillation columns are discussed in many textbooks 15-17 and review papers. 18-20 In general, there are three types of approaches. First, shortcut methods are frequently used to predict the key design parameters such as minimum reflux ratio, minimum number of trays, and minimum energy demand. Classical shortcut approaches include the Fenske's equation 21 for the minimum number of trays, the Underwood's method 22 for calculating the minimum reflux ratio, and Gilliland's 23 and Smoker's 24 equations for predicting the number of trays. Extending and generalizing the Underwood method, new shortcut procedures were later developed for complex columns 25,26 and batch distillation. 27 Shortcut methods were also proposed to obtain the minimum energy demand for nonideal systems. The boundary value method (BVM) 28 was introduced for homogeneous azeotropic distillation. The rectifying body method (RBM) was proposed for simple 29 and complex 30 distillation columns. Mathematical-programming-based feed angle method (FAM) was developed by Kraemer et al. 31 and later reformulated by Skiborowski et al. 32 to superstructure-based distillation network synthesis. Shortcut methods were also proposed for the design of reactive distillation columns, thermally coupled columns, and divided wall columns. 33-36 Second, rigorous methods are based on material and energy balances and equilibrium calculation for every tray. The enthalpy and vapor-liquid equilibrium (VLE) are described by equations of state (EOS) or thermodynamic models such as UNIQUAC 37 and UNIFAC. 38 The mixed-integer nonlinear programming model by Viswanathan and Grossmann 39 is applicable to predict optimal locations of the feeds and the number of trays required for a distillation column with multiple feeds, which were modified by Smith and Pantelides 40 to allow the feeds to distribute continuously across the column...

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“…Ruiz‐Marín et al proposed a method for the design of a fully thermally coupled distillation system with a postfractionator. The proposed method is based on a combination of Underwood's equations and the boundary value method . An improved DWC shortcut design approach has been developed by Seihoub et al to provide accurate models for each section of dividing wall columns.…”

Section: Introductionmentioning

confidence: 99%

Startup of divided wall column for high purity separation of aromatic reformate

Shen

Ling

2018

Can J Chem Eng

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Startup of distillation columns is one of the most difficult operations in the distillation process. Although the design and control of divided wall column (DWC) is mature recently, the startup procedure for divided wall columns still suffers a lack of knowledge. This paper investigates a startup policy of a pilot divided wall column used for high purity separation of an aromatic reformate. The aromatic reformate contains benzene, toluene, ethylbenzene, p-xylene, m-xylene, and o-xylene. Very high product purities above 99.95 wt% are specified. The proposed startup procedure is consisted of four steps, including total-reflux, benzene withdrawn, toluene withdrawn, and continuous feeding. This startup procedure has been successfully applied to the DWC pilot plant used for high purity separation of the aromatic reformate. Temperature and composition profiles of each step are presented. These profiles are used for determining the switching points of the near two steps and understanding the dynamic behaviour of the DWC.

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Shortcut Design of Fully Thermally Coupled Distillation Systems with Postfractionator

Cited by 7 publications

References 27 publications

Analysis of Dynamic Performance for Multiple Dividing Wall Distillation Columns

Analysis of Dynamic Performance for Multiple Dividing Wall Distillation Columns

From graphical to model‐based distillation column design: A McCabe‐Thiele‐inspired mathematical programming approach

Startup of divided wall column for high purity separation of aromatic reformate

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