CO_2和CF_3H抑制烟煤燃烧机理的对比试验研究

Comparative Research on the Mechanism of CO_2 and CF_3H Inhibiting Bituminous Coal Combustion

为研究二氧化碳和三氟甲烷对烟煤燃烧的抑制机理和抑制效果,采用自主研制的煤燃烧试验装置,对平煤八矿煤样进行了通入相同体积流量CO_2和CF_3H的煤燃烧灭火试验,测定了煤燃烧过程中温度场温度、标志性气体(O_2、CO和CH_4)组分和热释放速率的变化规律;并运用化学动力学软件CHEMKIN模拟了相同体积流量CO_2和CF_3H抑制CH_4/O_2火焰中主要自由基浓度、反应物与燃烧产物浓度随火焰高度的变化关系.结果表明:相比于煤粒空气条件下燃烧,在煤有焰燃烧阶段,通入CF_3H煤燃烧火焰中主要自由基生成速率、煤温上升速度、耗氧量、热释放速率以及CO和CH_4浓度下降速度比通入CO_2煤燃烧的更低;在煤阴燃熄灭阶段,通入CF_3H煤燃烧的煤温、CO和CH_4浓度下降速度比通入CO_2煤燃烧的更高,而通入CF_3H煤燃烧的耗氧量和热释放速率比通入CO_2煤燃烧的更低;说明CF_3H比CO_2具有更好的抑制烟煤燃烧的能力.

In order to research thoroughly the mechanism and effect of CO2 and CFsH inhibiting bituminous coal combustion, the self-developed test device of coal combustion was used to conduct the fire-extinguishing experiment on coal combustion under the condition of importing same flux CO2 and CF3H for coal samples in Eight mine of Ping Dingshan coal mine, and the change laws of temperature of temperature field, index gas formation （O2, CO and CH4） and heat release rate obtained from the coal combustion were measured; Meanwhile, the chemical kinetic software CHEMKIN was utilized to simulate the re]ationship of concentration of main free radicals, reactants and combustion products with the change of flame height in the same flow rate of CO2 and CF3H extinguishing the flame of CH4/O2. The results show that： compared to the free combustion of coal, in coal flame combustion stage, the generation rate of main free radicals in the flame, coal temperature rise rate, oxygen consumption, heat release rate as well as the speed of CO and CH4 concentration decline in coal combustion with CF3H are more lower than that of coal combustion with CO2; in the coal smoldering extinguishes stage, the coal temperature, the speed of CO and CH4 concentration decline in the coal combustion with CF3H are more higher than that of coal combustion with CO2, but the oxygen consumption and heat release rate are more lower. It follows that CF3H has more capacity of inhibiting bituminous coal combustion compared to CO2.