Practical residue curve map analysis applied to solvent recovery in non-ideal binary mixtures by batch distillation processes

Batch distillation inherent advantages has initiated recent search for process feasibility rules enabling the separation of azeotropic or difficult zeotropic binary mixtures thanks to the addition of an entrainer. A systematic procedure enabling to find suitable process and eventually suitable entrainer for the separation of zeotropic or azeotropic binary mixture is described. It brings together into practical use batch distillation process feasibility rules, chemical affinity insight and thermodynamic data analysis available in the literature. The procedure has been implemented in a wizard computer tool and is illustrated on the separation of the water – acetonitrile binary homoazeotrope. Through this tool, all possible 224 feasibility rules and 326 batch distillation sequence processes are checked systematically for each entrainer

Separation of ethyl acetate–isooctane mixture by heteroazeotropic batch distillation

This paper studies the separation of an ethyl acetate–isooctane mixture by heterogeneous azeotropic distillation in a batch rectifying column. An initial list of 60 candidates was studied but only methanol and acetonitrile were obtained as potential heterogeneous entrainers. These entrainers form a low boiling heterogeneous azeotrope with isooctane. Experimental verification of the miscibility gap with isooctane was performed at 25 °C for each entrainer giving a smaller region for methanol than for acetonitrile. Feasibility of the heterogeneous azeotropic batch distillation was carried out experimentally in a laboratory batch distillation column having 44 theoretical equilibrium stages and using a high reflux ratio. Several distillate fractions were taken as a function of the temperature at the top of the column. For both methanol and acetonitrile, the main fraction was defined by the condensed vapor providing a liquid–liquid split of the isooctane/entrainer heteroazeotrope into the decanter. Ethyl acetate impurity was detected in both decanted phases, but in much lower amount when using acetonitrile as entrainer. The process with acetonitrile also resulted in a shorter operating time and higher purity and recovery yield of isooctane as the main distillate product. Pure ethyl acetate remained into the boiler at the end of each process

Dimethylcarbonate as a new green solvent for fragrant extracts: Eextraction and recovery processes

National audienc

Ecodesign of a process for dimethyl carbonate: Influence of the degree of modelling of the methanolysis of urea

The environmental performance of emerging bio-based technologies must be assessed at an early stage of their development, when the process can still be modified for sustainable optimization, i.e. including environmental, social and economic aspects. The Life Cycle Analysis (LCA) methodology is already recognized as an effective solution for environmental analysis. However, the data obtained at the laboratory scale are incomplete in the initial stage of the eco-design of a new synthesis route, which complicates the inventory of the life cycle. Coupling a process modelling/simulation tool with LCA has proven to be an effective solution for providing inventory data. The simulation of a process is based on the selection of models allowing the environmental, energy and economic optimization of a technology to be developed on the production scale. The choice of models for the reaction and separation steps will certainly have a significant impact on the results of the environmental assessment. This article is dedicated to the study of the impact of the degree of complexity of the modelling of the reaction pathway on the environmental assessment of the process of methanolysis of urea to produce dimethyl carbonate (DMC)

Thermodynamic Insights on the Feasibility of Homogeneous Batch Extractive Distillation. 4. Azeotropic Mixtures with Intermediate Boiling Entrainer

This paper shows how knowledge of the univolatility and nidistribution line location and residue curve analysis help to assess the feasibility of batch extractive rectifying or stripping distillation of azeotropic mixtures by using an intermediate boiling entrainer. We consider five minimum boiling (minT) azeotropic mixtures AB with entrainer E, namely, acetone−heptane with benzene, methanol−toluene with triethylamine, methyl acetate−cyclohexane with carbon tetrachloride, dichloromethane−ethanol with acetone, and ethyl acetate−heptane with benzene; and one maximum boiling (maxT) azeotropic mixture, namely, chloroform−ethyl acetate with either 2-chlorobutane, isobutylchloride, bromopropane, or bromochloromethane. All ternary diagrams A−B−E belong to the 1.0-1b class, for which all three possible univolatility, !AB, !BE, and !AE, and unidistribution lines, KA, KB, and KE can exist. With application of the general feasibility criterion of Rodriguez-Donis et al. (Ind. Eng. Chem. Res. 2009, 48 (7), 3544−3559), both azeotropic components, A and B, accomplish the criterion, and they can be recovered, A in an extractive rectifier and B in an extractive stripper. The process efficiency of each alternative depends strongly on the location of the !AB univolatility line interception with the triangle edge, and also depends on the !BE (!AE) in the minT (maxT) case and of the unidistribution line KE closeness to the (E−B) (A−E) edge. Besides, choice of the rectification of A instead of the stripping of B is set by the ratio of !AE/!BE, the ratio of relative volatility variation of the binary mixtures between A or B and E

Selection of green solvents for organic photovoltaics by reverse engineering

International audienceFor a sustainable scale-up of solution-processed organic photovoltaic modules, the replacement of toxic solvents, generally used at laboratory scale, by alternative "green" solvents with a reduced impact on the environment and human health is a critical prerequisite. Yet, because of the complex relationship between solvent properties and device performance, the selection of alternative solvents relies primarily on time-consuming and costly trial-and-error approaches. In this work we propose a new methodology involving prediction of molecular properties and reverse design for a more efficient and less empirical selection of green and bio-sourced solvents. The method is applied to four different small molecule-and polymer based donor-acceptor blends. It allows to establish lists of possible alternative solvents ranked quantitavely by a global performance function encompassing all target properties. The actual performance of the highest ranked solvents are evaluated by using the selected solvents to elaborate photovoltaic devices and comparing the power conversion efficiencies with those obtained with devices processed from halogenated solutions. In all cases, the photovoltaic performances obtained with the alternative solvents are similar or superior to those of the standard devices, confirming the relevance of the new solvent selection method for solution-processed organic photovoltaic devices