Practical Applications of a Pure Prediction Method for Binary VLE to the Establishment of a High-Precision UNIFAC

Abstract

The original UNIFAC Version 5 and the modified UNIFAC models were evaluated using a pure prediction method (PPM) for the binary VLE. A total of 1264 binaries were used, because prediction errors by the PPM in the x, y VLE are less than 0.01. The modified UNIFAC can accurately predict the x, y VLE of limited 39% binaries of the 1264 binary systems at 101.3 kPa. At elevated temperatures, the original UNIFAC V5 can more accurately predict the temperature effects of infinite dilution activity coefficients than the modified UNIFAC, although accurately predicted binaries from the UNIFAC V5 for x, y VLE are limited to 29% of the 1264 binaries at 101.3 kPa. To establish a high-precision UNIFAC method, 798 new groups can be added in which the groups consist of substances themselves without subdividing into functional groups.

Modeling of the Vapor-Liquid Equilibria Properties of Binary Mixtures for Refrigeration Machinery

“…To overcome the problem of lack of the data on various kinds of refrigerant systems (binary mixture, ternary mixture, quaternary mixture, etc.) on an industrial scale, the researchers propose the use of numerical methods with thermodynamic developed models which are very reliable in solving many problems of the engineering under temperature and pressure conditions [4][5][6][7][8],these models are mainly divided into predictive or correlative thermodynamic models including equations of state, mixing rules and activity coefficient models [9].…”