Ultrasound-assisted demulsification of heavy fuel oil using lemon peel powder: A sustainable natural approach

Heavy fuel oil (HFO) commonly forms highly stable water-in-oil (W/O) emulsions due to the presence of natural surfactants such as asphaltenes and resins, creating difficulties in transportation and refining. In this study, a green demulsification approach was developed by integrating ultrasonic treatment (28 kHz) with lemon peel powder, a low-cost and renewable natural additive. Experiments were performed at 85°C with ultrasonic powers ranging from 100 to 800 W for 2–10 minutes, while lemon peel concentrations varied between 3000 and 15000 ppm. The optimum condition of 5000 ppm at 800 W for 10 minutes achieved a maximum demulsification efficiency of 80%, surpassing the commercial demulsifier RQ35, which achieved 65% under similar conditions. The improvement in phase separation is attributed to the synergistic effect of acoustic cavitation and the active components of lemon peel, including pectin and limonene, which enhance droplet coalescence and reduce interfacial stability. This study introduces a novel and environmentally sustainable demulsification strategy that reduces reliance on synthetic chemicals and demonstrates strong potential for practical implementation in industrial heavy oil treatment.