爆発実験容器中における炭じん雲の爆発跡ガスについて
1977 年 93 巻 1073 号 p. 483-488
詳細
1977 年 93 巻 1073 号 p. 483-488
Characteristics of aftergases of coal dust explosions were investigated for three high volatile bituminous coals. The apparatus used was a closed-type experimental one (Combustion and Flame 21, 2). Figure 1 shows the schematic diagram of the equipment and Fig. 2 the explosion chamber.
The composition of aftergas is shown on dry base in Fig. 4 to 6. Tars were not analyzed. The trends of H2, CO, CH4, and other hydrocarbons are similar to that of the explosion pressure shown in Fig. 3, that is, these gases have the peak near the optimum dust concentration at which the explosion pressure is the highest. Among these gases, CO is the most having the maximum value of about 8%. The concentration of hydrocarbons except CH4 is less than 1%. In general the descending order of hydrocarbon is CH4, C2H4, C2H2, C2H6, C3H6, C3H8, i-C4H10, and n-C4H10, and the amount of hydrocarbon decreases by one figure as number of carbon increases by one number. In hydrocarbons of the same carbon number unsaturated compounds predominate.
Regarding the effect of volatile content on the composition, no significant difference was found, although the amount of gases increases with increasing volatile content for increasing aftergas pressure as shown in Fig. 8. The effect of particle size is shown in Fig. 7.
Explosibility of aftergases was analyzed with a computer. The computation program used was the one developed by Yamao and Umezu. Figure 10 is an example of the diagram printed out by the computer. It was found that some aftergas-air mixture were explosive. Results for Ponbetsu coal are shown in Fig. 11. Also, it was experimentally confirmed that some aftergas-air mixtures were really explosive.
