Predicting evaporation dynamics of a multicomponent gasoline/ethanol droplet and spray using non-ideal vapour-liquid equilibrium models

Experimental validation of the process simulation a typical industrial bioethanol unit was conducted, comparing the obtained results with the information collected in an industrial plant. A standard solution containing water, ethanol and 17 congeners was chosen to represent the fermented must, whose composition was selected according to analyses of samples of industrial wines. A careful study of the vapour-liquid equilibrium of the wine components was performed. An attempt to optimise the industrial plant was conducted considering two optimising approaches: the central composite design (CCD) and the Sequential Quadratic Programming (SQP). The process was investigated in terms of bioethanol alcoholic graduation, ethanol recovery, energy consumption and ethanol loss. The results showed that the simulation approach was capable of correctly reproducing a real plant of bioethanol distillation and that the optimal conditions are slightly different from those used at the industrial plant investigated. Substantial fluctuations in wine composition were easily controlled for the two loop controls preventing an off-specification product. The optimised conditions indicate a distillation process able to produce bioethanol according to the legislation requirements and with appropriate steam consumption and loss of ethanol. However, for the production of alcohols with superior qualities, substantial changes in the production system may be required.

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Properties of Refrigerants from Cubic Equations of State

Revista de Chimie ◽

10.37358/rc.08.5.1827 ◽

2008 ◽

Vol 59 (5) ◽

Author(s):

Viorel Feroiu ◽

Dan Geana ◽

Catinca Secuianu

Keyword(s):

Experimental Data ◽

Vapor Pressure ◽

Equations Of State ◽

Ternary Mixtures ◽

Volumetric Properties ◽

Mixing Rules ◽

Saturation Curve ◽

Equilibrium Thermodynamic ◽

Liquid Equilibrium ◽

Binary And Ternary Mixtures

Vapour � liquid equilibrium, thermodynamic and volumetric properties were predicted for three pure hydrofluorocarbons: difluoromethane (R32), pentafluoroethane (R125) and 1,1,1,2 � tetrafluoroethane (R134a) as well as for binary and ternary mixtures of these refrigerants. Three cubic equations of state GEOS3C, SRK (Soave � Redlich � Kwong) and PR (Peng � Robinson) were used. A wide comparison with literature experimental data was made. For the refrigerant mixtures, classical van der Waals mixing rules without interaction parameters were used. The GEOS3C equation, with three parameters estimated by matching several points on the saturation curve (vapor pressure and corresponding liquid volumes), compares favorably to other equations in literature, being simple enough for applications.

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Vapour-Liquid Equilibria and Excess Thermodynamic Properties in Binary Systems of Cyclopentanone + Chloroalkanes in View of the Disquac and Unifac Group Contribution Models Extention

Revista de Chimie ◽

10.37358/rc.08.5.1823 ◽

2008 ◽

Vol 59 (5) ◽

Author(s):

Alexandru Birhala ◽

Dana Dragoescu ◽

Mariana Teodorescu

Keyword(s):

Binary Systems ◽

Excess Enthalpy ◽

Group Contribution ◽

Excess Properties ◽

Structural Effects ◽

Liquid Equilibrium ◽

Excess Thermodynamic Properties ◽

Different Types ◽

Thermodynamic Excess Properties ◽

Thermodynamic Excess

The data available in the literature and our recent data on vapour�liquid equilibrium (VLE), excess Gibbs energy, GE, and excess enthalpy, HE, for the homologous series of cyclopentanone + chloroalkane mixtures are examined in terms of the predictive group contribution models DISQUAC and UNIFAC. In our treatment, we present also how the structural effects and different types of molecular interactions are reflected by the thermodynamic excess properties of the mentioned series mixtures.

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