Effect of H2O and CO2 on propane, propene, and isopropanol oxidation at elevated pressures

Abstract

The article discusses research results on oxidation features of high-density fuel-enriched C3Н8/О2, C3Н6/О2, and C3Н7OH/О2 mixtures (ρfuel = 0.22–0.25 mol/dm3, ρO2 = 0.76–0.88 mol/dm3) diluted with argon, carbon dioxide, or water vapor (from 59 to 72% mol.) at the uniform heating (1 K/min) of tubular reactor to 640 K. Proceeding from the time dependences of the reaction mixtures temperature, it was revealed that the self-ignition temperature of fuels in the Ar medium increases in the following sequence: C3H6 < C3H7OH < C3H8. The self-ignition temperature of propane and propene is almost independent of the diluent nature, while the self-ignition temperature of isopropanol in the diluents medium increases in the following sequence: Ar < CO2 < H2O. The chain-thermal explosion was observed during the propane oxidation in Ar and H2O media, as well as during the isopropanol oxidation in Ar and CO2 media. Using mass spectrometric analysis, it was shown that the oxidation of propane in CO2 medium is characterized by a low degree of fuel conversion at almost complete consumption of O2, while the oxidation of propene is characterized by a low degree of fuel conversion and O2 consumption. Oxidation of fuels in the H2O medium occurs in several stages and is characterized by almost complete consumption of O2. In this paper we consider the mechanisms of chemical involvement of CO2 and H2O molecules in fuel oxidation.