The vapor phase submodel accounts for the vapor-liquid mass transfer, vapor-liquid equilibria, and the vapor convective flow from one tray to another. Due to the short residence time (Fig. (e)) and low concentration observed from the Aspen simulation, the vapor phase chemical reactions are assumed to be negligible. Details on the liquid-phase submodel and the film-phase submodel can be found in Sec. 3.1 and Sec. 3.3.