Singular points of reactive distillation systems

This paper aims to present the feasibility of conducting the transesterification of propylene glycol ether (PM) with methyl acetate (MeAc) in a reactive distillation (RD) column to improve the reaction conversion. The essential thermodynamic and reaction kinetic data of the reaction system were measured for the feasibility study. There is only one azeotrope, MeAc−MeOH, in the reaction system, and the NRTL model could describe well the thermodynamic behavior of this system. The transesterification of PM with MeAc is an endothermic reaction with activation energy E = 55.704 kJ•mol −1 . The feasibility was analyzed by residue curve maps (RCM), showing that full conversion of PM could be realized by RD with a mole ratio of MeAc−PM larger than 2.882. The intensification effect was experimentally verified in a batch RD column. Finally, some important parameters are given through the conceptual design to develop a continuous RD column for the transesterification of PM with MeAc.

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Feasibility Study of Reactive Distillation for the Production of Propylene Glycol Monomethyl Ether Acetate through Transesterification

Wang

et al. 2017

“…Although the analysis above was obtained merely by comparison between the reactive flash-cascade model and the ∞/∞ analysis method, it can be extended to other current feasibility analysis methods, for example, Venimadhavan et al's method 20 and Qi et al's method. 15 These methods had the same composition equation of singular points as eq 3 at the column bottom. The same expression form indicated that the possible bottom products predicted by these two methods were also related to a finite separating degree.…”

Section: ∑ υ υmentioning

confidence: 99%

“…Beside the example presented in this work, some calculated results in the literature also supported the conclusion acquired in this work from another viewpoint. For example, in the work of Qi et al, 15 the feasibility analysis for the IPOAC production process by esterification showed that the transformed compositions of HOAC and IPA in the top discharge were 0.425 and 0.656, respectively, at Da = 0.33. This discharge composition did appear in a real RD column with single feed and a Da number of 0.33 when the separation degree of this RD column was finite, and its reflux ratio and tray number of the column were 0.7 and 15, respectively.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

“…3−6 Besides the feasibility of the process, it can also provide necessary information for further conceptual design and experimental verification while the process is feasible. 7−9 Based on the different simplification and abstraction of the real RD process, various feasibility analysis methods and models were proposed and developed to acquire as much information as possible, for example, shortcut design methods, 10,11 the continuous multiphase reactor model, 12,13 the reactive flashcascade model, 14 and the singular point equations established by Qi et al 15 In general, a feasibility analysis was carried out with various Damkoḧler numbers Da as the parameter, and it can influence the existence and location of fixed points in the residue curve map. Therefore, feasible separations can be classified as a function of the Damkohler number.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Finite Separating Degree in Feasibility Analysis Methods of Reactive Distillation Process

Sha

et al. 2015

A ∞/∞ analysis method was developed to evaluate the effect of feasibility analysis methods on designing the reactive distillation (RD) process. Its mathematic derivation revealed that results from the reactive flash-cascade model were the same as results from the ∞/∞ analysis method only if the predicted column discharge was a pure compound or a common azeotrope under chemical equilibrium, but those two results were different when the predicted column discharge was a reactive azeotrope. The same phenomenon also appeared in comparison between the singular point equation method and the reactive flash-cascade model rebuilt by a single mole-based parameter. In the case of the reactive azeotrope appearing in the column discharge, both the theoretical discovery and the case study suggested that the separating degree of a RD column predicted by the feasibility analysis was finite, and it may be broken through in reality by means of imposing greater separating power, such as more theoretical trays or a bigger reflux ratio. Results from the feasibility analysis should be checked carefully because appropriate operation parameters can change the predicted separating performance of the RD column.

“…Recently, Qi et al 25 found that the conditions of all kinds of azeotropes, i.e., nonreactive, kinetic, and reactive azeotropes, in mulicomponent systems can be generalized into a simple relationship in the form of transformed variables presented by Barbosa and Doherty 3 and Ung and Doherty. 26,27 These conditions are illustrated as the potential singular point surface (PSPS), where all azeotropes are located.…”

Section: Introductionmentioning

confidence: 99%

Geometrically Locating Azeotropes in Ternary Systems

Sundmacher

2005

Self Cite

A geometrical method is provided to locate all kinds of azeotropes, i.e., nonreactive, kinetic, and reactive azeotropes, in homo-and heterogeneous ternary systems. The mass balance conditions of azeotropes are geometrically demonstrated as reaction kinetic surface (RKS), which can be further generalized as the potential singular point surface (PSPS). The azeotropes can be directly located by two sets of RKS's based on different components. However, it is more convenient to use PSPS with one set of RKS due to its important property; i.e., the PSPS consists of all kinds of azeotropes and all pure components such that the PSPS can be predicted starting from pure components. A continuation method is used to determine the PSPS and the RKS. Several nonreactive and reactive systems with homogeneous and heterogeneous liquid mixtures are illustrated.