Pyrolysis of C8-C16 hydrocarbons with different molecular structures using high-pressure micro-reactor with GC-MS/FID

Abstract Understanding the relationship of hydrocarbon chemical structure and pyrolysis is of great significance for both composition designing/screening and optimization of endothermic hydrocarbon fuels (EHFs). In this work, the pyrolysis of C8 to C16 hydrocarbons (9 normal alkanes, 14 iso-alkanes and 8 cycloalkanes) were studied on a high-pressure micro pyrolysis reactor equipped with GC-MS/FID at 600−700 °C and 3.0 MPa. The pyrolysis of iso-alkanes produces more C3 or C4 alkenes and less C2H4 than normal alkanes due to the presence of substituent and less CH2 groups. Based on the conversion and products distributions, the heat sink index (HSI) of hydrocarbons was defined to characterize their physical and endothermic heat sink. For alkanes with same carbon number, the HSI of iso-alkanes with monosubstituent in the central carbon chain is the highest, following by normal alkanes, dimethylalkanes, indicating the significant impacts of the position and number of substituents. While for cycloalkanes, n-alkylcyclohexanes had relatively higher HSIs. Generally, the new insights into hydrocarbon molecular structure-products distributions/heat sink relationships are important for the EHFs design and production for advanced aircrafts.