1-Hexene serves as a pivotal constituent in the fabrication of industrial polyethylene materials. Functioning as a precursor, 1-Hexene facilitates the production of superior-quality polyethylene products while concurrently mitigating plastic consumption through its provision of barrier properties to thinner films.
The utilization of ethylene trimerization reaction within a tubular gas-lift reactor configuration1, encompassing gas distribution volumes, reactor dimensions (riser-lower tube assemblies), and a gas-liquid separator, emerges as a promising technology for the synthesis of 1-Hexene. Nonetheless, this technique necessitates further hydrodynamic scrutiny to optimize its operational efficiency.
In pursuit of this optimization, a comprehensive industrial plant 3D Computational Fluid Dynamics (CFD) model has been devised to forecast gas hold-up, liquid circulation dynamics, and localized concentration profiles of constituents within a 1-Hexene production gas-lift reactor. Methodological frameworks for multiphase hydrodynamics have been preliminarily investigated through a single-tube model (Fig. 1). Calibration of model parameters has been performed in accord with equation of state formulations, Henry’s law principles, mass transfer criteria, diffusion models, viscous flow laws, multiphase modeling techniques, and both single-step and multi-step chemical kinetics, alongside considerations for heat transfer dynamics. Subsequently, the validated parameters have been extrapolated to a full industrial-scale steady-state CFD model. Validation of the model has been undertaken against experimental and analytical datasets acquired from a pilot plant reactor. Encouragingly, the CFD model exhibits a reasonably close agreement with pilot
experimental data, with the accuracy of mass fraction predictions for outflow components in vapor and liquid phases falling within a range of ±10%.
The progression toward a transient model promises to deliver insights into pivotal operational parameters such as the circulation ratio of the mixture within tubes, the uniformity of gas saturation across the entire volume, and the conversion rate under prescribed operating conditions.
[1] Kulchakovskii, P.I. and Arkatov, O.L. (2021) ‘Process for trimerization of ethylene and apparatus for
trimerization of ethylene’.