Kinetic study of H-abstraction and preliminary pyrolysis of n-decane in post-injection fuels

Abstract

The combustion and pyrolysis process of n-decane was investigated via quantum chemical method to enhance the understanding of post-injection fuels. The hydrogen abstraction reactions were the main reactions that initiated combustion and pyrolysis of n-decane via H atoms and CH3/OH/NO2 radicals. The potential energy surface of hydrogen abstraction and preliminary pyrolysis was determined via high precision CBS-QB3 and M06–2X/6–311++G (d,p) methods. RRKM - Master Equation theory had been utilized to calculate the rate constants of isomerization and β-dissociation reactions in the temperature range of 300–2000 K. In this PES, the ε-site was the most advantageous site in contrast with others and the α-site has the highest energy barrier and was the most challenging hydrogen abstraction site. The isomerisation reactions of decyl radicals play a crucial role in the combustion and pyrolysis of n-decane at low temperature, particularly via 1,5-H shift and 2,5-H shift reaction. At high temperatures, the scission of the CC bond becomes the primary mechanism. Additionally, modified information was incorporated into the detailed model of n-decane combustion and pyrolysis. The modified model exhibited good agreement with experimental measurements of the mole fractions of various significant products in Jet-stirred reactor (JSR) experiments. The research provides a foundation for future investigations of n-decane combustion and pyrolysis support.