Abstract

The present work deals with fitting literature data of liquid – liquid equilibria and to obtain a new correlation for non-randomness parameter suitable to use in NRTL activity coefficient model.New simple correlation is proposed for modifying the original three-parameter NRTL activity coefficient model to make it a true two-parameter model. The performance of the proposed expression is compared with the original three-parameter NRTL activity coefficient model, in correlating LLE data of binary systems, as well as in predicting binary systems from infinite-dilution activity coefficients and ternary systems from binary data. To ensure the results had physical significance, the obtained parameters were used to predict the infinite activity coefficients. Properties at infinite dilution are of interest as they usually indicate the maximum non-ideality of the system.The model was successfully applied to correlate liquid - liquid equilibria, and low temperature activity coefficients. A large database of data was collected for the investigation and it covers a wide range of composition, temperature and pressures. It was found that the proposed form of non-randomness parameter gave the best results.

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The article was added to IASJ on 2015-02-03

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