Entropy Flow and Energy Efficiency Analysis of Extractive Distillation with a Heavy Entrainer

Abstract

The minimization of the entropy production is equivalent to minimizing the work or energy consumption required by a separation process. Sources of entropy creation during the extractive distillation of a minimum-and maximumboiling azeotropic mixture with a heavy entrainer are evaluated at each column stage in accordance with the second law of thermodynamics, and the distribution of entropy flow in different sections of the column is analyzed. Results show that mixing on feed trays and heat exchange in the reboiler and condenser are the main sources of entropy production. The temperature of the main feed and entrainer feed does not significantly affect the irreversibility of the process at the reference temperature of all flows. Although optimal values can be proposed to achieve a minimum isothermal work, the energy loss of the real process steadily increases with increases in the entrainer/feed flow rate ratio and reflux. The influence of the feed tray shows that product purity tends to vary inversely with energy loss.

Thermodynamic Topological Analysis of Extractive Distillation of Maximum Boiling Azeotropes

“…The separation of the maximum-boiling mixture acetone/chloroform with the proposed solvents exhibit class 1.0-1a, 1.0-2, and 3.1-4. The thermodynamic insights published in previous work (Shen et al, 2013a;Benyounes et al, 2014;Benyahia et al, 2014;Lelkes et al, 2002;Lang et al, 1999;Rodriguez-Donis et al, 2012;Shen et al, Gerbaud, 2013b) and validated for the 1.0-1a and 1.0-2 ternary mixture class are applied here, and the general feasibility criterion previously established for ternary mixtures including only one azeotrope (1.0-1a or 1.0-2) is now, for the first time, extended to that including three azeotropes (class 3.1-4).…”

“…A heavy entrainer E has a boiling temperature higher than A and B; an intermediate entrainer E has a boiling temperature between the A and B; a light entrainer E has a boiling temperature lower than A and B. In industry, the extractive distillation entrainer is usually chosen as heavy (high boiling) component mixtures (Luyben and Chien, 2010;Lang et al, 1994;Rodriguez-Donis, 2009;Shen 2012;Shen et al, 2013a;Benyounes et al, 2014;Benyahia et al, 2014). Theoretically, any candidate entrainer satisfying the feasibility and optimal criteria can be used, no matter whether it is a heavy, light, or intermediate entrainer.…”

Investigation into optimization condition of thermal stimulation for hydrate dissociation in the sandy reservoir

“…Entropy production represents the loss of thermodynamic usefulness. Namely, a higher entropy production is an indicator of higher amount of energy consumption [41]. Hence, the process optimization, from thermodynamic point of view, corresponds to minimizing the entropy production [42].…”

On Entropy Generation and the Effect of Heat and Mass Transfer Coupling in a Distillation Process

“…This process involves a high energy consumption and has an inherently low thermodynamic efficiency. In this regard, energy optimization in such distillation processes is an important issue [1][2][3], and so the reduction of energy consumption in distillation has been the subject of intensive research [4][5][6][7]. One may address these problems through four kinds of thermodynamic methods applied to the analysis of energy consumptions: using only energy balances, considering second law efficiency, by studying the exergy behavior and through nonequilibrium thermodynamics [8][9][10], the two latter combining both the first and second laws.…”