横跨温度对丁烷裂解的影响

Effects of Crossover Temperature on Pyrolysis of n-Butane and i-Butane

采用自由基反应模型,针对中国石化开发的CBL-Ⅲ型裂解炉,以正丁烷、异丁烷及其混合物为原料,考察了横跨温度对丁烷裂解时关键组分的转化率、裂解产物中结焦前体的含量、裂解炉辐射段燃料气消耗及辐射段炉管最高管壁温度的影响。计算结果表明,无论原料中正丁烷与异丁烷的比例如何变化,横跨温度不高于665℃时丁烷转化率均不大于5%,此时造成横跨管结焦的前体炔烃和芳烃在产物中的含量均低于1×10-5(w),因而在长期运转时不会导致横跨管结焦;采用尽可能高的横跨温度对降低辐射段燃料气消耗和辐射段炉管最高管壁温度都有明显的益处。

Based on the radical reaction mechanism,in the pyrolysis of n-butane,i-butane and their mixtures,the effects of crossover temperature on the butane conversion,coking precursor content,fuel consumption in radiation section and maximum tube wall temperature were studied.The results showed that no matter how widely the feedstock composition changed,if the crossover temperature was not higher than 665 ℃,the butane conversion was not more than 5％.At that time,the contents of the coking precursors（alkyne and arene） in the pyrolysis products were under 1 × 10-5（w）,which meant that it won＇t result in any coking deposited on the crossover tube during long running.The high crossover temperature can be beneficial to lowering the fuel consumption and maximum tube wall temperature.