水热处理对含油污泥热解特性及动力学影响

Effect of hydrothermal treatment on pyrolysis characteristics and kinetics of oily sludge

利用热重分析仪研究了水热处理对含油污泥(OS)热解特性的影响,并使用Kissinger-Akahira-Sunose(KAS)和Ozawa-Flynn-Wall (FWO)的方法对其热解动力学进行了分析,确定了经过不同水热温度处理后的含油污泥在不同热解阶段的表观活化能,考察了水热处理及其水热温度对含油污泥热解特性及动力学参数的影响。热分析的结果表明:水热处理使得含油污泥在热解不同阶段的终止温度向较低温度区间移动,在相同的转化率下经过水热处理后的OS在不同热解阶段的表观活化能均低于原样。随着水热反应温度从160℃增加到240℃,根据FWO法估算的OS在热解第一阶段的平均表观活化能从75.20kJ/mol增加到78.28kJ/mol,热解第二阶段的平均表观活化能从151.04kJ/mol降低到144.18kJ/mol,热解第三阶段的平均活化能从171.12kJ/mol增加到了192.59kJ/mol。

This paper used a thermogravimetric analyzer to study the changes in the pyrolysis properties of oily sludge(OS) before and after hydrothermal treatment. At the same time, the apparent activation energies of the samples were calculated by two model-free methods, Kissinger-Akahira-Sunose(KAS)and Ozawa-Flynn-Wall(FWO). The apparent activation energy of oily sludge treated at different hydrothermal temperatures in different pyrolysis stages was determined. The effects of hydrothermal treatment and hydrothermal temperature on the pyrolysis characteristics and kinetic parameters of oily sludge were investigated. The thermal analysis results showed that the temperature range in different pyrolysis stage intervals shifted to a lower level and the weight loss rate increased significantly in the first stage and the third stage due to the change in oil type and content after hydrothermal treatment. At the same conversion rate, the apparent activation energy of OS after hydrothermal treatment at different pyrolysis stages was lower than that of OS. According to the FWO method, as the hydrothermal reaction temperature increased from 160℃ to 240℃, the apparent activation energy of OS in the first-stage and the third-stage pyrolysis increased from 75.20kJ/mol and 171.12kJ/mol to 78.28kJ/mol and 192.59kJ/mol,respectively, and the average apparent activation energy in the second stage of pyrolysis decreased from 151.04kJ/mol to 144.18kJ/mol.