Supercritical olefin coordination polymerization technology is one of the most important progresses in polyolefin industry

and accurate calculation of the binary phase equilibrium of this supercritical system with polymer is the key for the design and operation of this process. In this study

the equation of state of perturbed-chain statistical associating fluid theory (PC-SAFT EOS) with updated parameters is applied to binary phase equilibrium in supercritical ethylene polymerization system. Based on the pure component parameters and phase equilibrium data in literatures

the binary interaction parameters between supercritical fluid-solvent

supercritical fluid-monomer

comonomer (1-butene)

chain transfer agent (hydrogen)

circulation cooling gas (nitrogen) and polymer (PE) are regressed

and calculation results are compared with experimental data in literatures. The results show that re-parameterized PC-SAFT can accurately predict the thermodynamic properties and phase equilibrium of supercritical ethylene coordination polymerization system in a wide range of temperature (340-380 K) and pressure (2.0-7.0 MPa). The PC-SAFT EOS is validated by industrial data. The calculated supercritical fluid mixed density

vapor mixed density

and molar ratio of hydrogen to ethylene agree very well with industrial data for two product grades in the industrial process

with an average error less than 3%. The results provide a solid basis for further simulation and optimization of this supercritical process.