低阶煤热解条件对高炉喷吹半焦燃烧性能及动力学特性的影响

采用热重分析法研究了不同热解条件下半焦的燃烧性能和动力学特征，利用Ozawa法求取动力学参数。结果表明，热解温度越低、保温时间越短时，半焦的燃烧性能越好；热解升温速率对半焦燃烧过程的反应程度影响不大；粒度越大，燃烧性能差异性越明显。热解温度对半焦燃烧性能影响较大，550℃是本研究中制备高燃烧反应性半焦的适宜热解温度。两种不同粒度原煤制得的半焦均随转化率增大，活化能减小。1~3 mm原煤在热解温度为550℃时所得半焦在燃烧过程中符合反应级数模型，化学反应为限制性环节，反应最概然机理函数为f(α)=(1–α)2。

Effect of low-rank coal pyrolysis conditions on combustion performance and kinetic characteristics of semi-coke for blast furnace injection

Taking the typical low-rank coal in northern Shaanxi as the research object in this work, the combustion performance and kinetic characteristics of semi-coke under different pyrolysis conditions were studied by thermogravimetric analysis, and the kinetic parameters were obtained using the Ozawa method. The average activation energy of all samples was obtained by the equal conversion method. The results showed that the lower the pyrolysis temperature and the shorter the holding time were, the better the combustion performance of semi-coke was; the larger the particle size was, the more obvious the difference in combustion performance was. The pyrolysis heating rate had little effect on the combustion performance of semi-coke. Pyrolysis temperature had a large effect on the combustion performance of semi-coke. 550℃ was the suitable pyrolysis temperature for preparing semi-coke with high combustion reactivity in this study. With the increase of the conversion rate, the activation energy of semi-coke prepared with two kinds of raw coal with different particle sizes decreased. When the pyrolysis temperature of 1~3 mm raw coal was 550℃, the semi-coke obtained during combustion conformed to the reaction order model. The chemical reaction was the limiting link, and the most probable mechanism function of the reaction was f(α)=(1–α)2.