Phase Behavior and Phase Equilibria for The Polydisperse Polyethylene + Ethylene + Hexane System at High Pressures and Temperature: Experiments and Correlations

Rizqy Romadhona Ginting; Daichi Nakata; Kazunori Himemura; Ikuo Ushiki; Shin-Ichi Kihara; Shigeki Takishima

doi:10.37934/arfmts.112.2.4353

Authors

Rizqy Romadhona Ginting Study Program of Chemical Engineering, Department of Industrial and Process, Institut Teknologi Kalimantan, Indonesia
Daichi Nakata Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Japan
Kazunori Himemura Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Japan
Ikuo Ushiki Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Japan
Shin-Ichi Kihara Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Japan
Shigeki Takishima Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Japan

DOI:

https://doi.org/10.37934/arfmts.112.2.4353

Keywords:

Phase behavior, phase equilibria, polydisperse polyethylene, Sanchez-Lacombe EoS, solution polymerization

Abstract

This study aims to provide experimental phase equilibrium and phase behavior data for polydisperse PE + ethylene + hexane system. Polydisperse PE (Mw 30.0 kg/mol, PDI 4.2) was used with feed PE weight fraction, ⱳ_F,PE, of 0.02 to 0.20. The experiments based on a synthetic method were conducted at 473.2 K using an apparatus consisted of an equilibrium cell equipped with sampling tubes for solvent-rich and polymer-rich phases. The LL phase separation pressure increased by about 1 MPa for 1 wt% increase in ethylene concentration. The weight fraction of PE in solvent-rich phase, ⱳ_S,PE, decreased as the ⱳ_F,PE and pressure decreased. Similarly, the weight fraction of PE in polymer-rich phase, ⱳ_P,PE, also decreased as the ⱳ_F,PE decreased. The solvent-rich phase contained lower molecular weight fractions of PE, while the polymer-rich phase contained higher molecular weight fractions. These results were correlated and predicted with the Sanchez-Lacombe (S-L) EoS. Finally, the effects of pressure and ⱳ_F,PEon solvent recovery ratio were investigated with the S-L EoS. The results provided in this study could be used to obtain the higher hexane recovery by controlling the LL separation pressure.