石油沥青在连续热和空气老化中化学族组成的变化及动力学研究

Investigation of Changes and Kinetics of Chemical Group Compositions of Petroleum Asphalts in Continuous Heat and Air Aging

本文在120～180℃范围内详细考察了欢三联和胜利直馏沥青在连续热和空气老化中化学族组成妁变化.结果表明,随热和空气老化时间的增长,沥青的饱和烃组分含量基本不变,芳香烃组分含量逐渐减少,而沥青质组分含量逐渐增加。在较低温度(120～140℃)下,胶质组分含量稍有增加,未形成甲苯不溶物组分。但在较高温度(180℃)下,胶质组分含量先增加后下降,甲苯不溶物迅速增加.随热和空气老化温度的升高,各组分含量的变化更为显著。欢三联沥青各组分的表现老化速度常数为(4.252～23.59)×10^(-3)h^(-1),表现老化活化能为29.96～36.34kJ/mol。胜利沥青各组分的表现老化速度常数为(6.083～24.24)×10^(-3)h^(-1),表现老化活化能为14.67～15.48kJ/mol.本文所提出的连串反应动力学模型很好地解释了石油沥青在连续的热和空气老化中化学族组成的变化规律,各组分含量的理论计算值与实测值相吻合,其差值一般小于3％.

The changes of chemical group compositions of Huansanlian asphalt (HA) and Shengli asphalt (SA) were studied in continuous heat and air aging at 120～180 ℃ The experimental results showed that at given temperature the contents of saturate constituents of two asphalts changed very little, aromatic constituents decreased, while asphaltenes increased gradually during continuous heat and air aging. At lower temperatures (120～140℃) the contents of resins increased slowly and toluene insolubles were not formed, but at higher temperatures(180℃) the resins increased at first and then decreased and the toluene insolubles increased quickly. The higher the aging temperature, the more remarkably the various constituents of asphalts would change. The apparent aging rate constants and the apparent aging activation energies of various constituents of HA were respectively(4.252～23.59)×10^(-3)h^(-1) and 29.96～36.34kJ/mol, and those of SA were (6.083～24.24)×10^(-3)h^(-1) and 14.67～15.48kJ/mol. The changes of chemical group compositions of petroleum asphalts during continuous heat and air aging could be well explained by the kinetic model of sequential reaction presented in the paper. The constituent contents calculated by the model were identified with those determined in the test. The difference between the calculated content and the test one was generally smaller than 3%.