Kinetic Study on Gaseous Hydrocarbon Release of Le-ping Bark Coal during Low Temperature Pyrolytic Process in O2-Enriched Conditions

Gas release characteristics of coal during low temperature oxidation process were investigated in order to prevent coal spontaneous combustion. Based on the basic principle that the release rate of gaseous products increases during coal pyrolysis in O₂-enriched conditions, kinetic characteristic of low-weight molecular hydrocarbons for Le-ping bark coal were experimentally studied by using a coal self-heating experimental facility. The results show that the logarithmic release rate of seven kinds of C₁ ~ C₄ low-weight molecular hydrocarbons (ln¿) for Le-ping bark coal is linearly correlated with the reciprocal of absolute temperature (1/T) within the temperature range of 293 ~ 673 K. The kinetics of coal during their self-heating oxidation processes were consistent with a typical Arrhenius S.A. kinetic characteristic. The apparent activation energies (Ea) of seven hydrocarbons are follows by ascending order: Ea(C₂H₆)<Ea(C₃H₈)<Ea(n-C₄H₈)<Ea(C₂H₄)¿Ea(CH₄)<Ea(i-C₄H₈)<Ea(C₃H₆), while the gas release critical temperatures (T_m) are T_m(C₃H₈)<T_m(n-C₄H₈)<T_m(i-C₄H₈)<T_m(C₂H₆)<T_m(C₂H₄)¿T_m(CH₄)<T_m(C₃H₆). The various hydrocarbons demonstrated the different gas release critical temperatures, release rates and the apparent activation energies.