油基岩屑热等离子体处置的熔渣特性研究

Slag characteristics of oil-based drill cuttings treated by thermal plasma

关键词:  热等离子体  油基岩屑  玻璃体  熔融  重金属 

Key words:  thermal plasma  oil-based drill cuttings  glassy phase  melt  heavy metal

摘要:

目的 探究油基岩屑采用热等离子体熔融方式处置的熔渣特性。方法 以处理功率、处理距离、处理时间为因素设计正交试验,利用XRD、XRF、SEM、重金属浸出等手段判定油基岩屑熔融前后变化及无害化处理效果。结果 ①输入功率对油基岩屑热等离子体熔融行为具有显著的影响,功率大于13 kW时油基岩屑会转变为球状的玻璃熔渣,功率为22 kW时熔渣表面光滑度有所下降；②输入功率对熔渣玻璃体的质量分数影响最大,热等离子体处理距离对熔渣酸溶失率影响最大；当熔融温度在1 300 ℃以上时,熔渣玻璃体的质量分数均能达到90％以上；③熔渣中Cd、Ni、Zn、Pb的浸出质量浓度分别降至0.200 mg/L、1.000 mg/L、0.027 mg/L、0.100 mg/L以下,满足相关政策法规资源化利用要求。结论 利用热等离子体可以将油基岩屑熔融成玻璃态的熔渣,同时将重金属固封在玻璃体内部,降低重金属的浸出,满足无害化的需求。研究结果可为油基岩屑的热等离子体熔融工业化应用提供一定参考。 

Abstract:

Objective The characteristics of molten slag produced by hot plasma melting of oil-based drill cuttings were investigated. Methods The orthogonal experiment was designed with treatment power, treatment distance and treatment time as factors. XRD, XRF, SEM, heavy metal leaching and other means were used to identify the changes of oil-based drilling cuttings before and after melting and the effect of harmless treatment of oil-based drilling cuttings. Results (1) The input power has a significant effect on the thermal plasma melting behavior of oil-based drilling cuttings. When the power is greater than 13 kW, oil-based drilling cuttings turn into spherical glass slag. When the power is 22 kW, the surface smoothness of the slag decreases. (2) The orthogonal test finds that the input power has the greatest influence on the mass fraction of the slag glassy phase, and the thermal plasma treatment distance has the greatest effect on the acid dissolution rate of the slag. When the melting temperature is above 1 300 ℃, the glassy phase mass fraction of the slag can reach more than 90%. (3) Thermal plasma can completely remove the organic matter in the oil-based drill cuttings. The contents of Cd, Ni, Zn and Pb in the slag are reduced to less than 0.200 mg/L, 1.000 mg/L, 0.027 mg/L and 0.100 mg/L, meeting the requirements of relevant policies and regulations about resource utilization. Conclusion sThermal plasma can be used to melt oil-based drill cuttings into glassy slag and seal heavy metals in the glass plase to reduce the leaching rate of heavy metals to meet the needs of harmless. The research results can provide a certain reference for the industrial application of thermal plasma melting technology of oil-based drilling cuttings.