Study on hydrogen-rich gas condensation and CO2 droplets separation trajectory and liquid film growth characteristics in supersonic separator

The supersonic condensation swirl separation technology presents a promising environmentally friendly approach for the pretreatment and purification of hydrogen feedstock gas, as well as facilitating an efficient carbon capture process. However, the film-forming behavior of CO2 droplets in the hydrogen-rich supersonic separator after the cyclone stage remains unclear and requires further exploration. This study first establishes an H2-CO2 condensation model based on the Euler-Euler framework to resolve the nucleation and droplet growth dynamics. Subsequently, the discrete phase model (DPM, Eulerian-Lagrangian) and Euler wall film model (EWFM) are integrated to investigate droplet trajectories and liquid film growth under swirling conditions. Ultimately, we undertake a quantitative analysis of the impact of CO2 concentration and temperature of the incoming hydrogen feed gas on both liquid film thickness and separation efficiency. The findings reveal that an increase in CO2 content and a decrease in temperature within the hydrogen-rich gas enhance the formation of condensed droplets with larger diameters. This, subsequently, result in a marked improvement in both separation efficiency and liquid film thickness, highlighting the potential of this technology to revolutionize hydrogen purification and carbon capture processes.