十氢萘的超临界裂解性能分析

The analysis of decalin pyrolysis property under supercritical conditions.

以十氢萘为吸热型碳氢燃料的模型化合物，研究其在550～610℃和0．1～3．5MPa条件下的热裂解过程．实验表明：不同温度（特别是相对较高的590和610℃）下，十氢茶在0．1～2．0MPa压力下的转化率增加较为显著；十氢萘热裂解的主要气体产物有甲烷、乙烷、乙烯、丙烷、丙烯和碳原子数大于3的组分（C3＋）等；在相同温度条件下，甲烷、乙烯的含量随压力增加而降低；乙烷、丙烷、丙烯和C3＋的含量随压力增加而增加．裂解的气相产物中烯烃含量随温度升高而降低．液相产物主要包括环戊烷类、环戊烯类、环己烷类、环己烯类、苯类、茚类、萘类和十氢萘异构化产物等．根据液相产物的主要成分，推测了可能的裂解过程．由十氢茶双自由基引发，自由基通过氢转移、伊断裂、异构化、脱氢和加成反应等方式继续反应形成目标产物．

Thermal cracking of decalin, as a model endothermic hydrocarbon fuel, is studied in a batch reactor under different pressures （0.1-3.5 MPa） and temperatures （550-610℃）. The results show that： The conversion of decalin has an obvious increase from 0.1 to 2.0 MPa, especially at relatively high temperatures of 590 and 610℃ ; In the gaseous products, methane, ethane, ethene, propane, propene and hydrocarbons with more than three carbon numbers are found to be the major components; With an increase of the pressure, the relative content of methane or ethene decreases and that of ethane, propane or propene increases simultaneously; The content of alkenes in gas phase products decreases with the temperature rising; In the liquid products, alkylcyclopentane, alkylcyclopentene, alkylcyclohexane, alkylcyclohexene, alkyl benzene, indene, naphthalene and isomerization products of decalin are found to be the major components. A probable mechanism of the thermal cracking of decalin is proposed in order to explain the product distribution. The pyrolysis of decalin is initiated by diradicals. The formation of final products comes from H-transfer,β-scission, isomerization, dehydrogenation or addition reaction with these radicals.