高温下渣熔融对煤焦-CO2气化反应特性的影响

在STA449F3型热天平上采用等温热重法研究了加入不同比例粗渣的煤焦在反应温度900～1380 ℃的气化反应性。利用热重-差示扫描量热法(TG-DSC)对煤焦的热行为进行分析,主要考察了加入不同比例粗渣、反应温度对煤焦反应性的影响。结果表明,煤焦-CO₂反应过程中,气化反应性和碳转化率可根据煤灰熔融流动温度分为相对低温段和高温段。在低温段,加入粗渣增加了煤焦的气化反应性和碳转化率;在高温段,加入粗渣会减小煤焦的碳转化率,并当粗渣加入量超过一定比例时,会降低煤焦的气化反应性。气化初期反应速率可根据粗渣熔融流动温度分为低温区域的化学反应控制和高温区域的扩散控制。

Effects of molten slag on coal gasification reaction with CO2 at elevated temperature

The CO2 gasification reactivity of coal chars blended with different proportions of coarse slag were investigated by using an STA449F3 thermo-balance in the isothermal mode at the temperature range from 900 ℃ to 1 380 ℃.The thermal behavior of the sample was studied using thermo-gravimetric analysis and differential scanning calorimetry(TG-DSC),and the two regions(i.e.the low temperature region and the high temperature region) for the gasification reactivity and carbon conversion of coal chars were defined according to the flow temperature of coal ash fusion.The gasification reactivity and carbon conversion of coal chars with coarse slag added are improved in the low temperature region.But the addition of coarse slag decreases the carbon conversion,and the gasification reactivity of coal chars blended with coarse slag to certain ratio also decreases in the high temperature region.It is indicated that the initial gasification reaction of coal chars is chemically controlled in the low temperature region,and diffusively controlled in the high temperature region.