Abstract:
A heat exchanger network (HEN) for the process of methanol synthesis has been studied by pinch design analysis. Great economic and energy savings were realized by the pinch analysis in comparison to the existing plant. Also, it was found that it is possible to reduce the requirements for the consumption of utilities. The HEN was reconstruded by adding new heat exchangers. In order to produce new HEN, the capital costs had to be increased, but the total cost trade-off between the capital and energy costs will be decrease by 30 %.

Abstract:
In this work the Peng-Robinson-Stryjek-Vera (PRSV) equation of state coupled with the Huron-Vidal-Orbey-Sandler (HVOS) rule was tested for the correlation of the excess enthalpy (HE) and the excess heat capacity (cpE) alone and simultaneously. The HVOS mixing rule incorporates the NRTL equation as the GE model. All calculations were performed using the linear and reciprocal forms of the temperature dependent parameters of the models. For all the evaluations the 1,4-dioxane+n-alkane systems were chosen having in mind the unusually W-shaped concentration dependence of cpE for these systems. The correlation of the HE and cpE data alone for all the investigated systems using four coefficients and for the simultaneous correlation of HE+cpE data using six coefficients of the temperature dependent parameters of the PRSV-HVOS models could be considered as being very satisfactory.

Abstract:
The Peng-Robinson-Stryjek-Vera (PRSV) equation of state (EOS) coupled with a modified two parameter van der Waals one-fluid mixing rule (MvdW1) and the Huron-Vidal-Orbey-Sandler mixing rule incorporating the NRTL equation as a GE model was used for the correlation of excess enthalpy (HE), excess heat capacity (CpE) and the simultaneous correlation of both properties. All calculations with temperature dependent parameters of EOS models were applied to 1,3-dioxolane+n-alkane systems. The correlation of the HE and CpE data alone with four coefficients and the HE+CpE data with six coefficients of the temperature dependent parameters of the HVOS-NRTL models could be considered as very satisfactory.

Abstract:
The simultaneous correlation of VLE and excess properties (HE, cPE) for diether + n-alkane systems was performed in our previous paper by the cubic equation of state which incorporates the activity coefficient model (CEOS/GE).With the same aim, in the present work, a completely different approach based on a polynomial equation (Kohler model) was considered. Thismethod gave results on the same systems which could be estimated as being comparable to GEOS/GE models for the simultaneous correlation of two and, with considerably improved fits, of three properties.

Abstract:
The Kojima-Moon-Ochi (KMO) thermodynamic consistency test of vapour liquid equilibrium (VLE) measurements for 32 isothermal data sets of binary systems of various complexity was applied using two fitting equations: the Redlich-Kister equation and the Sum of Symmetrical Functions. It was shown that the enhanced reliability of the fitting of the experimental data can change the conclusions drawn on their thermodynamic consistency in those cases of VLE data sets that are estimated to be near the border of consistency.

Abstract:
The NpT - Gibbs ensemble Monte Carlo computer simulationmethod was applied to predict the vapour–liquid equlibrium (VLE) behavior of the binary systems ethane + pentane at 277.55 K and 310.95 K, ethane + hexane at 298.15 K, propane + methanol at 313.15 K and propane + ethanol at 325.15 K and 425.15 K. The optimised potentials for the liquid simulating (OPLS) model were used to describe the interactions of alkanes and alcohols. The simulated VLE predictions are compared with experimental data available for the pressure and phase composition of the analyzed binary systems. The agreement between the experimental data and the simulation results is found to be generally good, although slightly better for system in which both components were nonpolar.

Abstract:
Although many cubic equations of state coupled with van der Waals-one fluid mixing rules including temperature dependent interaction parameters are sufficient for representing phase equilibria and excess properties (excess molar enthalpy HE, excess molar volume VE, etc.), difficulties appear in the correlation and prediction of thermodynamic properties of complex mixtures at various temperature and pressure ranges. Great progress has been made by a new approach based on CEOS/GE models. This paper reviews the last six-year of progress achieved in modelling of the volumetric properties for complex binary and ternary systems of non-electrolytes by the CEOS and CEOS/GE approaches. In addition, the vdW1 and TCBT models were used to estimate the excess molar volume VE of ternary systems methanol + chloroform + benzene and 1-propanol + chloroform + benzene, as well as the corresponding binaries methanol + chloroform, chloroform + benzene, 1-propanol + chloroform and 1-propanol + benzene at 288.15–313.15 K and atmospheric pressure. Also, prediction of VE for both ternaries by empirical models (Radojkovi , Kohler, Jackob–Fitzner, Colinet, Tsao–Smith, Toop, Scatchard, Rastogi) was performed.

Abstract:
The excess molar volume VE of the binary liquid systems acetonitrile + methanol and acetonitrile + ethanol has been evaluated from density measurements at 298.15 K and at atmospheric pressure over the entire composition range. A vibrating tube densimeter, type Anton Paar DMA 55, was applied for these measurements. The Redlich Kister equation was used to fit the experimental VE data.

Abstract:
The excess molar volume VE of the binary liquid systems acetonitrile + methanol and acetonitrile + ethanol, experimentally determined in the previous part, were correlated by the PRSV CEOS coupled with the vdW and TCBT mixing rules. The results obtained show that the number and position of the interaction parameters of these models are of great importance for a satisfactory fitting of VE data.