压力对轻质原油氧化动力学参数的影响

利用高压差示扫描量热仪(PDSC)研究了不同压力下轻质原油的氧化放热特性,并结合Friedman方法计算了反应体系的活化能,分析了不同反应阶段压力对氧化动力学参数的影响。结果表明:随着压力升高,放热起始温度、峰值温度和反应结束温度均趋向低温,放热量也随之增大,尤其低温氧化放热速度大幅提高,氧化反应明显加强,说明压力增大导致原油在低温下更容易发生氧化反应;活化能在低温氧化前期迅速上升再下降,进入低温氧化后期趋于稳定,到高温氧化阶段再次上升,活化能随反应进程的波动,说明原油反应行为或反应速度发生了变化;对比不同压力下各反应阶段的活化能发现,活化能均随压力升高而降低,说明压力对氧化反应有促进作用,压力越大,反应越容易进行。

Influence of pressure on oxidation kinetics parameters of light crude oil

The oxidation heat release characteristics of light crude oil under different pressures were studied by high pressure differential scanning calorimeter(PDSC).The activation energy of the reaction system was calculated by Friedman method,and the effect of pressure at different reaction stages on the oxidation kinetics parameters was analyzed.It is concluded that with the increase of pressure,the initial temperature,peak temperature and end temperature of exothermic reaction move towards low temperature,and the exothermic heat also increases.Especially,the exothermic rate of low temperature oxidation increases greatly,and the oxidation reaction strengthens obviously,which indicates that the increase of pressure makes crude oil more prone to oxidation reaction at lower temperature.The activation energy rises rapidly and then decreases in the early stage of low temperature oxidation,and tends to be stable in the late stage of low temperature oxidation,and rises again in the high temperature oxidation stage.The fluctuation of activation energy with the reaction process indicates that the reaction behavior or reaction speed of crude oil has changed.By comparing the activation energies of different reaction stages under different pressures,it is found that the activation energy decreases with the increase of pressure,which indicates that pressure promotes the oxidation reaction.The higher the pressure is,the easier the reaction will be.