Study on the co-pyrolysis characteristics of oil-based drill cuttings and lees

The co-pyrolysis characteristics of oil-based drill cuttings (OBDC) and lees were studied through investigating the effects of pyrolysis temperature, pyrolysis time, heating rate, and mixing ratio on the pyrolysis/co-pyrolysis products. X-ray diffraction (XRD), scanning electron microscope (SEM), gas chromatography-mass spectrometry (GC-MS), and thermogravimetric-mass spectrometry (TM-MS) were used to analyze the pyrolysis products and pyrolysis procedure. The results showed the presence of a synergistic effect between OBDC and lees in the co-pyrolysis process. Under optimal conditions: mass ratio of OBDC: lees at 7:3, holding temperature at 350 °C, holding time for 60 min and heating rate at 10 °C/min, the petroleum content in the solid product obtained from the mixed sample was 491.9 mg/kg, which complies with the grade A of GB 4284-2018. “Agricultural Sludge Pollutant Control Standard.” In addition, the quality of the liquid gas product and gas product by co-pyrolysis was improved. This study provides a reference for reducing the generation of hazardous pyrolysis substances in pyrolysis products, to prevent environmental hazards from the pyrolysis of OBDC or lees.