The major species concentration, dissolved oxygen concentration, and the temperature at each tray, the condenser, and the reboiler in the debutanizer are shown in Fig. , where the feed to the debutanizer contains an air-saturated level of dissolved oxygen. Aspen simulation shows that dissolved oxygen in the feedstock gets distilled out and results in a higher concentration of oxygen in the top part of the column. The O 2 concentration decreases drastically in the bottom section. Concentrations below 10 -18 mol/m 3 in the Aspen output show numerical noise and are set to zeros in the subsequent steps of the modeling.