Experimental and kinetic study on the laminar flame propagation of cyclopentanone at elevated pressures: understanding its flame chemistry and comparison with cyclopentane and cyclopentanol

Cyclopentanone, a promising clean alternative fuel derived from biomass, was investigated in this work for its laminar burning velocities (LBVs). Experiments were conducted in a constant-volume cylindrical combustion vessel under an initial temperature of 443 K, initial pressures of 1 to 5 atm, and equivalence ratios ranging from 0.6 to 1.5 using high-pressure. The newly obtained experimental data were used to validate three representative kinetic models of cyclopentanone combustion from the literature. Among them, the Li model (Energy Fuels, 2021, 35: 14023−143034) provided the most accurate predictions of the experimental data. Based on the Li model, kinetic analyses incorporating sensitivity analysis and rate of production analysis were conducted to systematically investigate the effects of equivalence ratio and pressure on the LBVs of cyclopentanone. The results indicate that vinyl-related reactions play significant roles in cyclopentanone flames, with C₂H₃ + H = C₂H₂ + H₂ being the most critical inhibiting reaction under rich conditions. With the increase of the initial pressure, the sensitivity coefficient of H + O₂ (+ M) = HO₂ (+ M) gradually increases and exceeds C₂H₃ + H = C₂H₂ + H₂ under equivalent conditions. Furthermore, a comparison of LBVs with those of cyclopentane and cyclopentanol—both compounds with similar five-membered ring structures—shows that cyclopentanone exhibits significantly faster flame propagation. This behavior is mainly attributed to the unique molecular structure of cyclopentanone, which facilitates the generation of reactive radicals such as C₂H₃ and H during the combustion process, effectively promoting its flame propagation.