Kinetic modeling of 1-methylnaphthalene pyrolysis at high pressure (100Â bar)

- Exhaustive primary mechanism of 1-MNA pyrolysis based on free-radical reactions was built.
- Partial secondary mechanism includes reactions involving polyaromatics.
- Pyrolysis mainly leads to naphthalene, methane and dimers of 1-MNA.

In this paper a kinetic modeling of 1-methylnaphthalene (1-MNA) pyrolysis at high pressure is presented. The kinetic scheme proposed is based on previous experimental results obtained on 1-MNA pyrolysis experiments conducted at moderate temperature, from 400 to 443 °C, and for a pressure of 100 bar. The kinetic modeling involves 49 species and 95 reactions. Kinetic parameters of the elementary reactions were chosen from previous experimental kinetic studies, theoretical calculations and group contribution method estimations. The yields of the main products, naphthalene, methane, dimers of 1-MNA, and secondary products, 2-MNA, dimethylnaphthalene isomers, hydrogen, are well reproduced by the modeling until 40% of conversion of 1-MNA. Above this range of conversion, a more accurate and detailed scheme is necessary to take into account the numerous elementary reactions involving PAHs and the main products formed. Flow rate analyses of 1-MNA consumption and main products formation were done to elucidate the main reaction pathways. It showed that 1-MNA is consumed into a propagation loop producing methane, naphthalene and dimers. A sensitivity analysis was also performed and allowed the determination of the initiation reaction controlling 1-MNA thermal degradation. The modeling showed the crucial influence of dimers formation and further condensation pathways.

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