CO_2气氛对烟煤热解过程的影响

Effect of CO_2 Atmosphere on the Pyrolysis Process of Bituminous Coal

采用热重–傅里叶红外联用的方法研究徐州烟煤在Ar、N2和CO2气氛下的热解特性,考察CO2气氛下反应终温和升温速率对其失重和气体析出特性的影响。结果表明,CO2气氛对煤热解的影响主要在高温区,表现为对煤中碳酸盐分解的抑制作用和对煤焦的气化作用。反应终温900℃时,CO2气氛下CH4和C2H6的析出量较Ar和N2气氛下小,而CO析出量较大。CO2气氛下反应终温由700℃上升到1000℃,CH4和C2H6的析出量略有升高,CO析出量显著升高;升温速率提高,CH4、C2H6和CO析出量降低。

The pyrolysis characteristics of Xuzhou bituminous coal under Ar/N2/CO2 atmospheres were studied by thermo gravimetric （TG）-Fourier transform infrared spectroscopy （FTIR） technique. Effects of end temperature and heating rate on the weight loss and gas releasing characteristics of coal under CO2 atmosphere were analyzed. Results show that effects of CO2 on the pyrolysis characteristics take place mainly in the high temperature zone, acting as the inhibition of carbonate in coal from decomposing and the gasification of char. When the end temperature is 900 ℃, the releasing yield of CH4 and C2H6 under CO2 atmosphere are lower than those under Ar and N2 atmospheres while the CO yield is much higher. As the end temperature increases from 700℃ to 1000℃, the yields of CH4 and C2H6 increase a little while the CO yield increases a lot under CO2 atmosphere. As the heating rate increases from 10 ℃/min to 70 ℃/min, the yields of CH4, C2H6 and CO under CO2 atmosphere all decrease.