Thermal plasma vitrification treatment of oil-based drill cuttings: Product characterization and harmless transformation

Abstract

Oil-based drill cuttings (OBDCs) are hazardous wastes associated with the process of oil and gas extraction. In this paper, OBDCs were treated using a self-designed plasma vitrification system. The basic physicochemical properties of the OBDCs were analyzed, followed by a plasma vitrification mechanism investigation of the OBDCs. The environmental pollution risk of the vitreous slags obtained from thermal plasma treatment was also evaluated with the heavy metal extraction toxicity procedure. The batch of vitreous slags with an average glass phase content of 98.60% had a dense and smooth surface and an oxygen-to-silicon (O/Si) ratio ranging from 3.68 to 4.32, according to the findings. The melting temperature and treatment duration have a great effect on the loss ratio on acid dissolution. The leaching concentrations of Pb and Zn were 0.0004 mg/L and 0.068 mg/L, respectively, consistent with the chlorination reaction promoted by thermal plasma. Fourier transform infrared spectroscopy analysis showed that there was no organic matter in the vitreous slag, achieving the goal of harmless transition. The specific energy consumption of vitreous slags was predicted and verified by response surface methodology (RSM). This study describes the vitrification process and harmless treatment of OBDCs by thermal plasma technology, and vitreous slags have great potential for resource utilization.