利用沸石分子筛提高航空汽油辛烷值方法研究

Improvement of aviation gasoline octane number via adsorption by zeolite molecular sieve

航空汽油基础油辛烷值较低是制约航空汽油无铅化发展的主要因素。本研究对利用β-沸石分子筛分离2,2,4-三甲基戊烷与2-甲基庚烷混合物的可行性进行了考察。结果表明,在相同温度及压力下,β-沸石分子筛对2-甲基庚烷的吸附能力远优于2,2,4-三甲基戊烷,且组分的饱和吸附量随温度的升高而减少,随压力的增加而增加。双组分吸附试验证明了利用β-沸石分子筛完全能够实现2,2,4-三甲基戊烷与2-甲基庚烷的分离,这主要归因于分子筛本身的结构特征及同分异构体分子大小的差异。双组分吸附试验中,2,2,4-三甲基戊烷出口体积分数在某一时刻以后高于入口体积分数,这主要是因为吸附床内部发生了脱附现象。

The key factor to impede the development of the unleaded aviation gasoline was the low octane number of the aviation gasoline itself. The feasibility of separation of 2,2,4-methylpentane and 2-methylheptane by using β-zeolite molecular sieve was thoroughly studied. The experimental results showed that at the same temperature and pressure, the adsorption capacity of 2-methylheptane was higher than that of 2,2,4-trimethylpentane, and the saturated adsorption capacity of the single component decreased with the increase of adsorption temperature and increased with the increase of pressure. The isotherm adsorption experiments of 2,2,4-methylpentane and 2-methylheptane binary mixture confirmed that they could be separated via adsorption by β-zeolite molecular sieve, which was attributed to the structure characteristics of the molecular sieve and the size difference of the isomer molecules. During the isotherm adsorption experiments of the binary mixture, from a certain time the concentration of 2,2,4-trimethylpentane at outlet was much higher than that at inlet due to the desorption of 2,2,4-trimethylpentane in the adsorption bed.