钻井废液的超临界水氧化处理及动力学分析

Study on kinetics of supercritical water oxidation of waste drilling fluids

在反应温度为500-600℃、压力为25～30MPa、停留时间为30～600S的条件下，在连续式反应器中研究了钻井废液的超临界水氧化反应。结果表明：钻井废液的COD去除率可达90．00％以上；在600℃、停留时间为600S时，钻井废液氧化后，剩余收集液的COD〈120mg／K，满足《污水综合排放标准》（GB8978-1996）中的二级标准。用幂函数方程描述了氧化剂过量时钻井废液超临界水氧化的反应动力学规律，反应速率常数与温度的关系符合Arrhenius公式，随停留时间的增加、温度的升高，有机物的去除率显著增加；反应速率常数随压力升高而增加，但反应速率常数的增幅随压力的升高而减小，反应活化体积不是常数。在25MPa时，反应活化能和频率因子分别为（17745．43040±1114．98342）kJ／mol和1．1523×10^-4s^-1，模型计算值与实验值的误差在±15％以内。

The supercritical water oxidation （SCWO） of waste drilling fluids had been studied in the continuous reactor at 500-600℃, 25-30 MPa, and residence time 30-600 s. The results indicated that the removal efficiency of COD could be over 90%, whereas the residual COD of reaction liquid was found to be less than 120 mg/L under the residence time of 600 s and 600℃. The SCWO kinetics for waste drilling fluids COD disappearance was fitted with the power law equation. The relationship between the reaction rate constant and temperature followed the Arrhenius law. It was found that removal efficiency of organic contaminant species of waste drilling fluids obviously increased with increasing the residence time and temperature, whereas the vartion gap of the reaction rate constant decreased with increasing pressure and the activation volume wasn＇t a constant. At 25 MPa, the values of activation energy and frequency factor were （17 745. 430 40±1 114. 983 42） kJ/mol and 1. 152 3× 10^-4 s^-1, respectively. The deviations between calculation and experimental values were within ±15 %.