常温域における石炭の酸化発熱過程

炭層の自然発火に関する研究 (第2報)

抄録

Searching for the heat generation curve of coals by oxygen adsorption within therange from 30°C to 45°C, we investigated the susceptibility of coals to spontaneous heating.
Numerical calculations were developed with a sphere coalmodel for approximating the temperature rise inaccordance with results obtained by experiment.
Consequently, we came to following conclusions.
1) Assumingthat the initial temperature of model is 45°C and its surface is keeping on the same, thetemperature at the centre of model attained 47.7°C in 30minutesand it required 100 hours in order to drop 1°C.
2) The relationship between temperature andrate of heat generation can be expressed by means of the Arrhenius equation.
lnA=lnA₀-E/RT
The logarithm of the rate (lnA) is proportional to the reciprocal of the absolute temperature (1/T) witha slope of -E/R and an intercept of lnA₀, where E is the activation energy and Ris the gas constant.In this equation, A₀is the amount of heat generation in the initial oxidation process. Using the values of A₀, we can evaluate the susceptibility of coals to spontaneous heating.
3) According to our calculations, elapsing about 16.7 hours from be ginning of oxygen adsorption, the temperature of the model centre comes up to 100°C. After that, the rising curve of temperature has a more steep slope. Fromthese results, we can say that the heat of adsorption in the low temperature oxidation process leads to spontaneous combustion.