Harmless Treatment Technology of Oily Cuttings

Abstract Oily cuttings are hazardous wastes containing oil, hydrocarbons and heavy metals, which generate a significant risk to human and enviroment without appropriate treatment. The common treatment, including heating, burning, microbiological degradation and so on, are not fast and effective enough to solve the pollution problem caused by oily cuttings. This article provides a method with higher efficiency and lower cost. An intelligent cleaning agent, synthesized for cleaning oily cuttings, is easy to dissolve in water and makes oil and water easily emulsify during cleaning process, so as to achieve the purpose of removing oil. By adjusting the pH, the emulsion will be automatically demulsified after statis, and then the oil and water are separated from each other, which simplify the progress of treatment. Ultrasonic technology is assisted to clean the oily cuttings, which effectively reduces the amount of cleaning agent and increases the treating efficiency of the cleaning agent. In this paper, the effects of the cleaning agent dosage, heating temperature and ultrasonic time on the deoiling ratio are analyzed. The oil recovery rate is above 90% with the dosage of 7.5g/L oil cleaning agent under the 55 °C and 10 minutes. The recovered oil has good quality and meets the demand for preparation of oil-based drilling fluid. The residual wastewater, including the cleaning agent, can be reused as cleaning liquid by adjusting the pH to neutral and adding fresh cleaning agent. This technique improves the treating efficiency of oily cutting and greatly lower the cost, which would have a high value to popularize.