Universality analysis of the reaction pathway and product distribution in C5-C10 n-alkanes pyrolysis

Abstract

Hydrocarbons pyrolysis was of great significance for light olefins production. In this work, the pyrolysis of C5-C10 n-alkanes and n-alkane mixtures was studied at 650–800 °C under atmosphere to explore the universality of reaction pathway and product distribution. It was found that an increase of chain length and reaction temperature promoted pyrolysis activity, and the acceleration effect caused by increasing chain length was more noticeable at low temperature. An increase of chain length enhanced 1-hexene, 1,3-butadiene, cyclohexene and benzene formation, inhibited methane, ethane, propene and butenes formation, while hardly affected ethene and propane formation. Since the feedstock included both pure and mixed n-alkanes, the achieved regularity seemed universal for C5-C10 n-alkane pyrolysis. Based on the free radical mechanism and product distribution, the reaction network was proposed and discussed for C5-C10 n-alkanes pyrolysis. Although an increase of chain length promoted the pyrolysis activity in n-alkanes pyrolysis, it inhibited the cracking depth and light olefins formation. Fortunately, the negative effect of chain length on light olefins production was avoidable by tailoring reaction temperature.