CFD modeling of the ethylene-vinyl acetate copolymerization autoclave reactor: Effects of comonomer ratio on reactor dynamics and copolymer properties

Computational fluid dynamics (CFD) modeling of an industrial ethylene-vinyl acetate autoclave copoly- merization reactor was conducted to evaluate the effects of comonomer ratios on reactor dynamics and product properties, including the molecular weight distribution (MWD), and copolymer composition. To accurately predict the MWD of copolymer chains under highly nonideal mixing conditions at a reduced computational cost, the CFD-multicompartment model and probability generating function (PGF) trans - form were applied. The effectiveness of the developed model was validated by the satisfactorily consis- tent plant data and simulated results. The model revealed that an increase in the vinyl acetate (VA) content significantly decreased the temperature, promoting combinational termination and chain trans- fer to polymer reaction for a broad copolymer MWD. The pseudo-kinetic-based analysis showed that VA was consumed more slowly than ethylene, resulting in its lower value in the copolymer composition than that of the comonomer ratios. However, despite nonideal mixing, the copolymer composition was main- tained to be uniform for the copolymers produced over the entire reactor volume. In conclusion, the pro- posed model can be used to understand the governing behaviors of copolymerization under nonideal mixing conditions, design commercial copolymerization reactors, and predict copolymer product qualities.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

Computational fluid dynamics (CFD) modeling was used to evaluate the effects of comonomer ratios on the dynamics and properties of an industrial ethylene-vinyl acetate autoclave copolymerization reactor. The CFD-multicompartment model and probability generating function (PGF) transform were applied to accurately predict the molecular weight distribution (MWD) of copolymer chains under nonideal mixing conditions. The model was validated using plant data and simulated results, showing satisfactory consistency. The study revealed that an increase in the vinyl acetate (VA) content decreased the temperature and influenced the copolymer MWD and composition. Despite nonideal mixing, the copolymer composition remained uniform throughout the reactor volume. The proposed model can be used for understanding copolymerization behavior, designing commercial reactors, and predicting product qualities.