乙烯渣油结构解析及其热解行为

Structural Analysis and Pyrolysis Behavior of Ethylene Tar

以乙烯渣油为原料,采用1 H-NMR、13 C-NMR表征渣油组分中各类型H、C的分布,并联合基质辅助激光解吸电离飞行时间质谱、元素分析设计了乙烯渣油的平均分子结构模型,同时采用热重技术研究了其热稳定和热反应性,利用管弹式反应器研究了乙烯渣油在320℃、350℃和420℃N2保护下的热转化反应特征。结果表明,乙烯渣油的平均相对分子质量约为247,芳香度为0.76,平均分子结构中烷基侧链与环烷结构并存;当温度为320℃和350℃时,乙烯渣油的热转化以裂解反应为主,产物主要为轻质油和气体,无焦生成,且液相产物芳香度随温度升高逐渐增大;而温度为420℃时,缩聚反应加剧并有固体焦生成,液相产物芳香H(C)与脂肪H(C)的原子比也随之升高。

The average molecular structure of the ethylene tar was studied by a combination method of elemental analysis,1 H NMR,13 C NMR and matrix-assisted laser desorption and ionization timeof-flight mass spectrometry（MALDI-TOF-MS）.The thermal stability and thermal reaction of the ethylene tar was analyzed by thermogravimetric method.The pyrolysis behavior of the ethylene tar was investigated at temperature of 320℃,350℃ and 420℃ in a tube bomb reactor under N2 atmosphere.Results showed that in the average molecular structure of ethylene tar there were both naphthenic ring and alkyl substitutions,with an average molecular mass of 247 and the aromaticity value of0.76.During the pyrolysis process of ethylene tar,the cracking reaction was dominated at the temperature of 320℃and 350℃to produce light oils and gases with no coke-like products.The aromaticity value of the liquid product increased steadily with the increase of temperature.While the pyrolysis temperature increased to 420℃,the condensation reaction was intensified in the system,resulting in formation of solid coke and higher atomic ratio of aromatic H to aliphatic H,as well as aromatic C to aliphatic C.