基于热重质谱联用的沥青质燃烧特性分析

Analysis on combustion mechanism of asphaltene using TG-MS technique

为了分析沥青质的燃烧特性，利用热重质谱联用技术模拟了沥青质在空气环境中的燃烧．分别采用Coats-Redfern积分法和分布活化能模型计算了沥青质不同阶段的活化能，其中Coats．Redfem积分法将沥青质的燃烧过程分为2个阶段，其活化能分别为221．33和147．07kJ／m01．采用分布活化能模型计算了转化率为0．1～0．9的9个活化能，活化能从210．49kJ／mol逐渐降低至42．98kJ／m01．根据质谱图，确定了各个时刻逸出气体的种类和产量．2种活化能计算方法分别验证了沥青质燃烧过程中活化能逐渐降低，说明在燃烧过程中随着反应的进行，燃烧逐渐变得更容易发生．由质谱图与沥青质的热失重速率曲线比较可知，热失重速率峰值处气体逸出量最多．

To analyze the combustion mechanism of asphaltene, thermo gravimetric analyzer coupled with a mass spectrometer （MS） technique was used in a mixed gas environment of simulated air. The Coats-Redfern model and the distributed activation energy model （DAEM） were used to calcu- late the activation energy. The process of asphaltene combustion was divided into two stages by the Coats-Redfern model, with the activation energies being 221.33 and 147.07 kJ/mol, respectively. By the DAEM , nine activation energies from 210.49 to 42.98 kJ/mol were calculated when the conversion rate changed from 0.1 to 0.9. According to the MS pictures, the types and magnitudes of the gaseous products during asphaltene combustion at each time were identified. The results show that with the combustion processing, the activation energy is decreasing which means the combustion reaction becomes easier to happen. Compared with the derivative thermogravimetric curve and MS pictures, the maximum volume of gas released occurred at the peak points of the derivative thermo- gravimetric curve.