ClO2-oxidation-based demulsification of oil-water transition layer in oilfields: An experimental study

Separation of oil and water is well known as a key process in the oil industry. For the purpose of improving the efficiency of the oil-water separation, a novel ClO2-oxidation-based demulsification method for the treatment of oil-water transition layer in oil settling tanks was proposed and studied in the present paper. A series of lab experiments were performed to investigate the techniques and conditions of the ClO2-oxidation-based demulsification, including the reaction temperature, time, concentration, etc. It was observed that a high dehydration rate of 86.11% was achieved under an optimal reaction condition of 50 degrees C, 4 hours, 3.5% ClO2 concentration and 0.5% acid by volume. Tests concerning the corrosion to the steel tank illustrated that the corrosion rate of water layer after treated by ClO2 was lowered to 0.151 mm/a, which was below the national standard. Based on the theoretical analysis and experimental results, a mechanism was presented for understanding the ClO2 demulsification. The developed ClO2-oxidation-based demulsification technology can be practically applied to the pilot operations in oilfields.