Experimental and principal component analysis studies on minimum oxygen concentration of methane explosion

Abstract

Gas explosion has always been one of the leading disasters in chemical and mining industries, causing tremendous considerable casualties and property damage. It is very effective to control ignition parameters to prevent explosion accidents. To intensively investigate the impacts of C2H6/C2H4/CO/H2 mixtures on CH4 explosion, we added C2H6/C2H4/CO/H2 mixtures with different ratios (samples 1–4) and different volume fractions ([mixture] = 0–2.0 vol%) to CH4/air([CH4] = 7.0, 9.5 and 11.0 vol%) for measurement of the flammability limit and minimum oxygen concentration (MOC) for CH4 explosion in a 20-L spherical vessel. Changes of flammability limits of CH4 were obtained with the addition of C2H6/C2H4/CO/H2 mixtures at room temperature (18–22 °C) and pressure (1 atm). The experimental data about MOC of CH4 explosion were examined by principal component analysis (PCA). On the basis of experimental results, multiple regression models were established to determine the influences of principal components on MOC of CH4 explosion. The results clearly indicated that the impacts of organic and inorganic combustible gases on flammability limits of CH4 were significantly different. The involvement of sample 1 and sample 2 (main component is organic flammable gas) increased the explosive hazard degree (F value) of CH4 by 43.18% and 45.45%, respectively. However, it was increased by 15.91% and 4.55%, respectively after adding sample 3 or sample 4 (main component is inorganic flammable gas). Additionally, the required MOC for CH4 explosion was increased with the increase of C2H6/C2H4/CO/H2 mixtures, and they showed a quadratic parabola relationship. Moreover, the linear expressions between the concentrations of C2H6, C2H4, CO and H2 and the MOC of CH4 explosion were achieved by PCA. Based on these analyses, it is indicated that the effects of C2H6, C2H4 and CO were increasingly significant on MOC while H2 was just the opposite from the oxygen-rich state to the stoichiometric state and fuel-rich state for CH4/air mixture. The results presented in this paper can provide theoretical reference for the prevention and control of multiple flammable gas explosion.