煤在高浓度CO_2环境下的燃烧、气化及吸附实验

Experimental study on combustion,gasification and adsorption of coal in a CO_2-rich atmosphere

利用热重-差热分析(TG-DTA)探讨了大同煤样在20～1400℃,在不同O2浓度(≤5%)的CO2气体环境、不同升温速率及气体流量条件下的燃烧及气化反应特征。同时,对50～200℃条件下煤对二氧化碳(CO2)气体的吸附特性进行了研究。随后,应用能谱分析仪对残余灰分进行了碳含量分析。实验结果表明,煤在高浓度CO2氛围中的燃烧是在360～1100℃;煤在高浓度CO2氛围中的气化是在1100～1300℃。常压下当环境温度低于200℃时,煤对于100%CO2气体主要表现为物理吸附,且吸附量随温度的降低遵循阿伦尼乌斯方程。当温度低于1000℃时O2浓度对残余灰分中碳含量有着较大的影响;但是当温度高于1000℃发生气化反应后,残余灰分中碳含量的结果没有显示出过多地依赖O2的浓度。

Presented combustion and gasification reaction characteristics of Chinese Datong coal samples in the temperature range 20 ℃ to 1 400 ℃ using thermo gravimetric-differential thermal analysis （TG-DTA） under different O2 concentrations （≤5%） in a CO2-rich atmosphere,with different heating and gas flow rates.Coal CO2 gas adsorption characteristics were also measured under a temperature range 50～200 ℃.The samples of residual ash were subsequently analyzed by Energy Dispersive Spectrum analyzer to investigate carbon molecular ratio.In a CO2-rich atmosphere coal combustion is observed in the temperature range 360～1 100 ℃,whereas coal gasification occurre in the temperature range 1 100～1 300 ℃.There is 100% CO2 physical gas adsorption by coal at 200 ℃ under atmospheric pressure,and adsorption capacity follows the Arrhenius equation with decreasing temperature.O2 concentration has a larger effect on carbon molecular ratio of residual ash at 1 000 ℃,but carbon molecular ratio doesn’t show strong dependency on O2 concentration at 1 000 ℃ after gasification.