Pyrolysis and kinetic modeling investigation of 1-methoxy-2-propanol

Abstract

1-Methoxy-2-propanol (PM, CC(O)COC) is a simple and representative hydroxyl ether that has gained attention as an alternative biofuel. In this study, the pyrolysis of PM was investigated in an atmospheric pressure flow reactor within the temperature range of 573 to 1173 K. Gas chromatographs were utilized to detect the species produced during the pyrolysis experiment. Acetaldehyde, n-butene, i-butene, and acetone were newly identified among the eighteen products and intermediates in PM pyrolysis. Ab initio calculations were employed to investigate the potential energy surface and pressure-dependent rate coefficients of PM unimolecular decomposition. The energetically favored channel for unimolecular initiation reactions is found to be H₂O elimination. Based on the bond dissociation energies of PM, a detailed kinetic model consisting of 608 species and 3160 reactions was proposed with reasonable predictions against the experimental results. Rate-of-production analysis reveals that the consumption of PM is mainly controlled by H-abstractions involving H and CH₃ radicals at three different carbon sites to generate radicals C₄H₉O₂-1, C₄H₉O₂-2 and C₄H₉O₂-3, respectively. At 1023 K, the conversion rate of PM reaches around 75%, and the reaction 2CH₃ (+M) = C₂H₆ (+M) exhibits the greatest inhibition effect, while the reaction C₄H₁₀O₂=C₃H₆OH2-1+CH₃O has the greatest promotion effect on PM consumptions. The results contribute to better understand the pyrolysis behavior, enhancing the utilization of PM as a sustainable energy source.

Novelty and significance statement

1-Methoxy-2-propanol (PM) is an alternative biofuel, yet there is a significant lack of research exploring its kinetic behavior. The novelty of this work focuses on the atmospheric-pressure pyrolysis of PM. The PM pyrolysis experiments were carried out with newly detected intermediates and products involved in the process. To further enhance the understanding of PM kinetic behavior, a new kinetic model consisting of 608 species and 3160 reactions was developed. This model was utilized to predict the mole fractions of PM, H₂, CO and important intermediates and products during the pyrolysis process. Additionally, the ROP and analyses were conducted to shed light on the reaction routes. Before this work, there was a lack of comprehensive investigation into the kinetics of PM pyrolysis, making this study significant in bridging the knowledge gap in this field. The findings of this investigation not only contribute to our understanding of PM pyrolysis kinetics but also serve as a foundation for further exploration of oxygenated additives fuel. By elucidating the mechanisms and pathways involved in the pyrolysis of a specific oxygenated fuel, this work opens doors to study the pyrolysis kinetics of other biofuel and advancing our knowledge in this area.