Chemical insight into the ozone-assisted low-temperature oxidation of propane

Ozone addition is not only a promising method for combustion control and enhancement but also pro-vides a reliable platform to benchmark low-temperature oxidation chemistry. Studies of ozone-doped combustion provide additional insight into combustion chemistry at lower temperatures. This paper stud-ies the ozone-assisted low-temperature oxidation of propane in an atmospheric jet-stirred reactor (JSR) from 350 to 770 K. More than twenty species are measured and quantified using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). The experimental results show that even at temperatures as low as 450 K, the reaction of propane is initiated by o atoms that originate from the thermal decomposition of ozone. The reactivity of propane reaches a maximum at 650 K, decreases in the temperature range of 650 - 740 K, and then slightly increases from 740 to 770 K. The propane oxida-tion behavior observed in this study is effectively captured by NUIGMech1.3 combined with a Princeton ozone sub-mechanism. However, the mole fractions of certain species such as, CO, H2O, and H2O2 are over-estimated by the mechanism at temperatures above 700 K. Kinetics analyses indicate that fuel oxida-tion and intermediate species formation are sensitive to the reaction temperature which determines the competing reactions involving propyl-peroxy radicals and the formation of OH and H O2 radicals. These findings are significant in terms of improving the core mechanism and acquiring a deeper comprehension of the ozone-assisted low-temperature oxidation chemistry of alkanes.(c) 2023 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

Ozone addition is a promising method to control and enhance combustion and provides a platform to study low-temperature oxidation chemistry. This study investigates ozone-assisted low-temperature oxidation of propane and identifies the initiation of propane reaction by ozone thermal decomposition even at low temperatures. The reactivity of propane shows a maximum at 650 K and decreases in the temperature range of 650 - 740 K. The findings contribute to improving the understanding of the ozone-assisted low-temperature oxidation chemistry of alkanes.