Effect of methanol-water mixtures on the oxidation of n-heptane at low to intermediate temperatures: Experimental and numerical study.

Methanol is widely recognized as a carbon-neutral fuel. This work used synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) to study the oxidation process of water/methanol/n-heptane mixes in a jet-stirred reactor (JSR) at a pressure of 1 atm, equivalence ratios (ϕ) of 1 and a temperature range of 500–1100 K. The results of the experiment indicate that the inhibition of n-heptane's oxidation at low temperatures (500–740K) is the primary manifestation of the action of methanol/water mixtures on n-heptane oxidation. The strong interactions among the components of water/methanol/n-heptane mixtures at low temperatures are primarily between methanol and n-heptane. The higher the methanol content, the greater the strength of inhibition of n-heptane oxidation. This inhibitory effect primarily results from the competition of methanol with ˙OH radicals. It is noteworthy that the chemical kinetic interactions between methanol-water mixtures and n-heptane not only manifest changes in the ˙OH radical pools but are also associated with the intermolecular chemical kinetic interactions between peroxyalkyl radicals (ROO˙) and CH 3 OH. • The oxidation of water/methanol/n-heptane blends had been studied by the SVUV-PIMS. • Quantitative analysis was conducted on several crucial oxidative intermediates. • The mechanistic model for water/methanol/n-heptane blends was optimized. • The inhibition of n-heptane oxidation by methanol-water mixtures was analyzed. • Chemical interactions between methanol-water mixtures and n-heptane are revealed. [ABSTRACT FROM AUTHOR]