Combustion characteristics of three linear monohydric alcohols CH3(CH2)n-1OH (n = 16, 18, 22): Combined ignition experiments and molecular dynamics simulations

Abstract

Higher fatty alcohols play a vital position in modern industry, while the dust explosion hazard cannot be ignored. Three kinds of linear monohydric alcohols CH3(CH2)n-1OH (n = 16, 18, 22) were selected to explore the combustion characteristics through ignition tests and molecular dynamics simulations. The experiment consequences indicated that the flame propagation height of alcohols dust gradually aggrandized as the enlargement of dust concentration of 30–750 g/m3 and the flame propagation velocity presented two peaks. CH3(CH2)15OH had the highest flame propagation height and velocity, followed by CH3(CH2)17OH and CH3(CH2)21OH. The first flame propagation velocities of CH3(CH2)15OH, CH3(CH2)17OH, and CH3(CH2)21OH reached the maximum value at 500 g/m3, which were 16.47, 13.25, and 12.53 m/s, respectively. The second peak reached the maximum value at 750 g/m3, which were 20.07, 19.05, and 18.23 m/s, respectively. The combustion reactions of alcohols revealed that the decomposition of molecules was first due to the breakage of the CC bond, and the main products were mainly C2H4, H2O, CH2O, CO, and CO2. The production and consumption reaction processes of C2H4, CH2O, and other combustible gas products reasonably explained the flame continuous process and the variation of flame propagation. The TG test results indicated that the volatility and thermal conductivity of CH3(CH2)15OH, CH3(CH2)17OH, and CH3(CH2)21OH decreased sequentially, which confirmed the flame propagation and molecular dynamics combustion reactions of the three alcohols. The volatility of alcohols was the key factor determining the difference in the flame propagation behavior of alcohols dust.