A study of square-well statistical associating fluid theory approximations

Six square-well (SW) statistical associating fluid theory (SAFT) models, fi tted to the experimental saturated liquid volume and saturated vapor pressu re for pure n-alkanes, are analyzed for predicting the coexisting densities , second virial coefficients, and binary phase equilibria. The models that result in low values of the segment energy and weak molecular weight depend ence of the parameters are found to be more accurate for real fluids. The i nclusion of the dimer structure in the SW chain term seems to produce no si gnificant benefit for representing real substances. (C) 1999 Elsevier Scien ce B.V. All rights reserved.