Two alpha functions (BM

SRW) and three different mixing rules (MHV2

WS

HG) for the PR and RKSEOS were investigated in the vaporliquid equilibrium calculation of related binary systems for FischerTropsch synthesis oil systemFurthermore

two different equations of states (EOS) of SR-POLAR and PC-SAFT

together with two activity coefficient equations of UNIF-DMD and UNIF-HOC were investigatedThe results showed that various prediction methods had similar deviations for weakly polar systemsHowever

these method had different prediction abilities for other systemsUNIF-DMD

RKS-HG and RKS-MHV2 models gave more accurate prediction for nonassociating strongly polar system

RKS-MHV2 and UNIF-HOC models showed the smallest deviation for associating strongly polar system containing water

UNIF-HOC and SR-POLAR models showed the smallest deviation for associating strongly polar system containing acids

and UNIF-HOC

SR-POLAR models showed the smallest deviation for other associating strongly polar systems

while RKS-MHV2 and RKSHG took the second placePC-SAFT model would bring big deviation for unsymmetrical system when binary parameters were lacking

but would give small deviation for all systems when binary parameters were available.