柴油组成对十六烷值与十六烷指数关联性的影响

Effect of diesel oil composition on the correlation between cetane number and cetane index

考察了不同性质柴油以及烷烃、芳烃、烯烃含量对柴油十六烷值和十六烷指数关联性的影响。结果表明,中间基原油切割得到的柴油馏分十六烷值与十六烷指数吻合性好,对环烷基原油切割得到的柴油馏分十六烷值小于十六烷指数,石蜡基原油切割得到的柴油馏分十六烷值大于十六烷指数。直馏柴油十六烷值与十六烷指数关联最佳,加氢精制柴油次之,加氢裂化柴油最差。烷烃质量分数为30%～37%时,十六烷值与十六烷指数相近;芳烃质量分数为20%～30%时,十六烷值与十六烷指数相近,芳烃含量偏高时,十六烷值与十六烷指数关联性变差。当柴油密度为0.815～0.845g/mL时,十六烷指数采用GB/T11139—89计算较准确;当柴油密度大于0.845g/mL或小于0.815g/mL时,十六烷指数采用ASTMD4737—96四变量计算公式计算较佳。

The effects of diesel oil composition and contents of paraffin,aromatic,olefin on the correlation of cetane number and cetane index were investigated. The results showed that cetane number of cut from intermediate base crude was as large as its cetane index,cetane number of cut from naphthenic base crude was smaller than its cetane index,and that of cut from paraffin base crude was larger than its cetane index. The correlation between cetane number and cetane index for straight-run dissel oil was the best,followed by hydrofining diesel oil,and hydrocracking diesel oil was the worst. The cetane number and cetane index was similar at mass fraction of paraffin 30%-37% or aromatic 20%-30%,but with the increase of aromatic component,the correlation of the two became poor. When the density of diesel oil was 0.815-0.845g/mL,cetane index should be calculated according to GB/T 11139—89,and when the density was below 0.815g/mL or above 0.845g/mL,cetane index should be calculated according to ASTM D 4737—96.