Significant volumes of oily wastewater are discharged during oilfield extraction and require treatment and proper disposal to meet environmental regulations and mitigate environmental impact. The existing flotation process exhibits low efficiency in separating oil from water. In this study, hydrocarbon homologues are utilized, and low-boiling point media are vaporized to form bubbles for treating oily wastewater through flotation. The extraction and flotation processes contributed to improved oil removal efficiency by enhancing the bubble flotation effect. This study examined how the concentration of low-boiling point medium, the temperature of the extracted water, and the initial oil concentration influence the oil removal efficiency, and determined the optimal operating parameters. The highest oil removal efficiency was attained at a ratio of low-boiling point medium to produced water of 1.2%. At a produced water temperature of 45℃, the oil removal efficiencies of conventional bubbles and low-boiling medium bubbles were 48.15% and 72.15%, respectively. The maximum oil concentration load for low-boiling point medium bubble flotation was 600 mg/L, compared to 500 mg/L for air bubble flotation. Furthermore, during the investigation of various types of flocculants and compound flocculants to aid flotation, it was discovered that the dosage of polymerized aluminum chloride (PAC) and anionic polyacrylamide (APAM) at 38 mg/L and 5 mg/L, respectively, resulted in an oil removal efficiency exceeding 98%, representing a 5% improvement compared to single flocculant-assisted flotation.

oily wastewater treatment; low-boiling media; vaporization; extraction; bubble generation.