Experimental study on the treatment of oil-based drill cutting by pulsed dielectric barrier discharge plasma at atmospheric pressure

Abstract

Oil-based drilling cuttings produced in the process of oil exploration and shale gas development are harmful to the ecological environment. The emerging low-temperature plasma technology has shown potential for environmental protection. In this paper, pulsed dielectric barrier discharge (DBD) plasma was used to treat contaminated drilling cuttings at atmospheric pressure. The effect of adding active aluminium oxide (Al2O3) balls to the oil-based cuttings on the degradation rate of mineral oil was evaluated. Results showed that when the oil-based drilling cuttings were mixed with active Al2O3 balls, the highest degradation rate of mineral oil (68.1%) was achieved when the treatment time was 30 min. This rate was 41.8% higher than that obtained by DBD treatment alone. The Fourier transform infrared spectroscopy showed that the content of alkanes in the treated samples decreased significantly. The gas chromatography-mass spectrometry and ion chromatography analysis showed that formic acid, acetic acid, and other by-products were formed. The contents of C and H in the samples treated by DBD decreased. Overall, this study provides much-needed insights into the reaction mechanism and pollutant degradation process of the synergistic treatment system of pulsed DBD and active Al2O3 balls in the field of oil-based drilling cuttings treatment.