Eniko Haaz

Evaluation of the accuracy of modelling the separation of highly non-ideal mixtures: extractive heterogeneous-azeotropic distillation

Abstract The distillation based separation can be extremely complex if highly non-ideal mixtures are to be separated. In spite of different successfully applied unit operations there is still possibility to improve distillation technique and widen its toolbar. A new improvement in this area is the introduction of the extractive heterogeneous-azeotropic distillation (EHAD). This unit operation includes the merits of the extractive and heterogeneous-azeotropic distillations in one unit without an extra material addition. In spite of the complexity of this unit operation it can be efficiently applied and complex separation technologies can be simplified with its application. The separations of ternary and quaternary mixtures from the fine chemical industry show both in the modelled and the experimental results that the extractive heterogeneous-azeotropic distillation is an efficient tool of this area. Demonstrating the accuracy of EHAD, the separation of methanol–ethyl-acetate–water and ethanol–ethyl-acetate–water mixtures are examined and the EHAD is compared with conventional distillation techniques. These separation processes are rigorously modelled and optimized with dynamic optimization method in professional flowsheeting environment. The objective function is the total annual cost but the energy consumption is also investigated. The modelling results are verified with laboratory experiments, too. It can be concluded that the extractive heterogeneous-distillation is a capable method for the separation of these highly non-ideal mixtures.

Modelling of organophilic pervaporation to compete with distillation

Abstract In the case of process design a new graphical representation method is proposed on the basis of computer modelling of distillation and pervaporation. The new method relies on also vapour-liquid equilibrium data. The comparison can be performed on a common y-x equilibrium diagram of the mixture to be separated. In our work methanol-water, ethanol-water and isobutanol-water are the investigated systems. The alcohol permeate composition values are plotted over the feed composition. Permeate alcohol concentrations are calculated with the help of known separation factors and feed alcohol concentrations. The corresponding vapour-liquid equilibrium composition is also shown so that pervaporation and flash distillation could be compared. In the case of methanol and ethanol separation a lower separation capability of the different PDMS membrane is detected than a flash distillation. In the case of isobutanol-water mixture every calculated isobutanol permeate weight fractions of different organophilic membranes are above the equilibrium vapour concentration. The proposed graphical representation method visualizes the feasible operation ranges of distillation and pervaporation. It enables also the designing engineer for the proper selection of the separation method.

COD reduction of process wastewater with vacuum evaporation

Abstract Washing detergents in process wastewaters from fine chemical industry produce high Chemical Oxygen Demand (COD), which poses a serious environmental problem. Method has to be found, which follows the principles of circular economy so that the treated water can be recycled or reused. Heat pump vacuum evaporator is evaluated in order to reduce the Chemical Oxygen Demand of process wastewater with washing detergent content from initial 7500 mg O2/L to a lower value below the effluent limit , which is 1000 mg O2/L. Yield and COD rejection are determined for the evaluation of selected treatment. Experiments are investigated with LED Italia R150-v3 pilot apparatus. Different evaporation pressures were applied during measurements. It The highest removal or reduction of in the Chemical Oxygen Demand was reached certainly using the lowest possible pressure, which is 40 mbar.

Treatment of Pharmaceutical Process Wastewater with Hybrid Separation Method: Distillation and Hydrophilic Pervaporation

Abstract The work is motivated by an industrial problem, which is alcohol removal from pharmaceutical process wastewater. The aim of the study was to develop a complete hybrid operation is investigated. Ethanol dehydration, in combination with distillation and hydrophilic pervaporation, is used to investigate about the extent of separation of the ethanol-water mixture. The aim of this research is to rigorously model and optimize this hybrid operation in professional flowsheet simulator environment. The number of minimal theoretical plates of distillation column and minimal effective membrane transfer area are determined. Cost estimation is also examined according to Douglas methodology. Considering our results it can be concluded that, the distillation and hydrophilic pervaporation processes are suitable for separation ethanol and water in 99.5 weight percent purity

Parameter estimation for modelling of organophilic pervaporation

Abstract The work is motivated by an industrial environmental problem, which is ethanol removal from aqueous mixture. To complete this goal organophilic pervaporation of ethanol/water mixture through commercially available Sulzer PERVAP™ 4060 is investigated to obtain information about the removal of ethanol. The experimental results are obtained at different feed ethanol concentrations and temperatures. Our experimental data are evaluated with the semi-empirical pervaporation model (Valentinyi et al. 2013) of our improvement and it is found that the model can be applied also for this organophilic case. Linear and quadratic surfaces suiting (Model III) are also investigated in order to estimate partial permeate flux. The results of parameter estimation and modelling of the pervaporation show that the novel model that considers the concentration dependency of the transport coefficient (Model II) is also capable for the modelling of organophilic pervaporation and results in a better fit to the experimental data, than basic pervaporation model (Model I) and Model III.