The experimental system of 10 m3 large-scale multiphase combustion explosion tank was used for research into the explosion development process under the ignition conditions of methane-coal dust-air mixture, and the ov...The experimental system of 10 m3 large-scale multiphase combustion explosion tank was used for research into the explosion development process under the ignition conditions of methane-coal dust-air mixture, and the overpressure development processes of the mixture at different distances were obtained. For the methane-coal dust-air mixture with an equivalence ratio of 1, the explosion pressure and pressure rise rate reached their maximum under a methane concentration of 8% and a coal dust concentration of 25 g/m3, while the maximum explosion pressure and pressure rise rate both occurred 0.5 m away from the ignition point under a methane concentration of between 4.5% and 8%, and a coal dust concentration of between 25 g/m3 and 1 O0 g/m3. Moreover, the greater the explosion intensity of mixture, the closer the occurrence location of maximum overpres- sure was to the ignition source.展开更多
This work is focused on the performance prediction of pilot scale catalytic reverse flow reactors used for combustion of lean methane-air mixtures. An unsteady one-dimensional heterogeneous model for the reactor was e...This work is focused on the performance prediction of pilot scale catalytic reverse flow reactors used for combustion of lean methane-air mixtures. An unsteady one-dimensional heterogeneous model for the reactor was established to account for the influence of the reactor wall on the heat transfer. Results of the simulation indicate that feed concentration, switch time and compensatory temperature impose important influence on the performance of the reactor. The amount of the heat extracted from the mid-section of the reactor can be optimized via adjusting the parameters mentioned above. At the optimal operating conditions, Le. switching time of 400 s, feed concentration of 1% （by volume）, and insulation layer temperature of 343 K, the axial temperature of the reactor revealed a comparatively symmetrical ＂saddle＂ distribution, indicating a favorable operating status of the catalytic reverse flow reactor.展开更多
The explosive gases CO and C2H4, released mainly flammable gases during the process of coal self-ignition, are of the most important ingredients of the multi-component gases in goal areas, along with CH4. We have dete...The explosive gases CO and C2H4, released mainly flammable gases during the process of coal self-ignition, are of the most important ingredients of the multi-component gases in goal areas, along with CH4. We have determined some of the parame- ters of explosive properties of the one-component gases CH4, CO and C2H4 using an explosive trial device of polybasic explosive gas mixtures and emphasized particularly the effect on the limits of explosive concentration of the binary explosive mixed gases CH4＋CO, CH4＋C2H4, as a function of the amount of CO, C2H4 and inert flame resisting gases （N2, CO2）. The experimental results show that the effect of inert gases on the explosive limits of mixed gases, given the property of explosive gas, is obvious： the inert gases （N2, CO2） possess some inhibitory effects on the explosion of the multi-component explosive gas mixtures. The results will provide some experimental support to suppress the occurrence of the gas explosions in goaf areas and provide some directions for designing explosion-proof electric equipment and fire arresters.展开更多
文摘The experimental system of 10 m3 large-scale multiphase combustion explosion tank was used for research into the explosion development process under the ignition conditions of methane-coal dust-air mixture, and the overpressure development processes of the mixture at different distances were obtained. For the methane-coal dust-air mixture with an equivalence ratio of 1, the explosion pressure and pressure rise rate reached their maximum under a methane concentration of 8% and a coal dust concentration of 25 g/m3, while the maximum explosion pressure and pressure rise rate both occurred 0.5 m away from the ignition point under a methane concentration of between 4.5% and 8%, and a coal dust concentration of between 25 g/m3 and 1 O0 g/m3. Moreover, the greater the explosion intensity of mixture, the closer the occurrence location of maximum overpres- sure was to the ignition source.
基金Supported by the National High Technology Research and Development Program of China(2006AA030201)
文摘This work is focused on the performance prediction of pilot scale catalytic reverse flow reactors used for combustion of lean methane-air mixtures. An unsteady one-dimensional heterogeneous model for the reactor was established to account for the influence of the reactor wall on the heat transfer. Results of the simulation indicate that feed concentration, switch time and compensatory temperature impose important influence on the performance of the reactor. The amount of the heat extracted from the mid-section of the reactor can be optimized via adjusting the parameters mentioned above. At the optimal operating conditions, Le. switching time of 400 s, feed concentration of 1% （by volume）, and insulation layer temperature of 343 K, the axial temperature of the reactor revealed a comparatively symmetrical ＂saddle＂ distribution, indicating a favorable operating status of the catalytic reverse flow reactor.
基金The financial supports from the National Natural Science Foundation of China (No.50874088)the Changjiang Scholars and Innovative Research Team in University (No.IRT0856)
文摘The explosive gases CO and C2H4, released mainly flammable gases during the process of coal self-ignition, are of the most important ingredients of the multi-component gases in goal areas, along with CH4. We have determined some of the parame- ters of explosive properties of the one-component gases CH4, CO and C2H4 using an explosive trial device of polybasic explosive gas mixtures and emphasized particularly the effect on the limits of explosive concentration of the binary explosive mixed gases CH4＋CO, CH4＋C2H4, as a function of the amount of CO, C2H4 and inert flame resisting gases （N2, CO2）. The experimental results show that the effect of inert gases on the explosive limits of mixed gases, given the property of explosive gas, is obvious： the inert gases （N2, CO2） possess some inhibitory effects on the explosion of the multi-component explosive gas mixtures. The results will provide some experimental support to suppress the occurrence of the gas explosions in goaf areas and provide some directions for designing explosion-proof electric equipment and fire arresters.
