宁东煤煤焦-CO_2气化反应特性的原位研究

In-situ study on gasification reaction characteristics of Ningdong coal chars with CO_2

以典型宁东煤-梅花井烟煤和羊场湾烟煤焦为气化样品,并与典型气化用煤-神府烟煤焦对比,采用热重分析仪及高温热台-光学显微镜联用系统原位研究煤焦气化反应活性,并结合焦样理化结构特性的系统表征对其进行关联解释。结果表明,在相同气化温度下,三种煤焦的气化反应活性大小顺序为:羊场湾烟煤焦>梅花井烟煤焦>神府烟煤焦。由高温热台实验原位研究可知,随着煤焦-CO_2反应的进行,大部分煤焦颗粒反应形式以颗粒收缩进行,到达反应中后期,反应由颗粒收缩转变为缩芯形式,并通过投射面积收缩率可发现,相同反应时间下,羊场湾烟煤焦的投射面积收缩率最大,其后依次为梅花井烟煤焦和神府烟煤焦。气化反应活性的差异主要归因于不同煤焦理化性质间的差异:羊场湾烟煤焦的比表面积、炭结构无序化程度和K、Na、Ca总含量最大,其后依次为梅花井烟煤焦和神府烟煤焦。

Meihuajing coal and Yangchangwan coal from Ningdong,China are chosen as rawmaterials to study char gasification reactivity using thermogravimetric analyzer and in-situ heating stage microscope,and typical gasification coal-Shenfu bituminous coal char is used as reference char sample.The char physicochemical properties are systematically characterized.The results showthat the order for gasification reactivity of 3 chars at the same gasification temperature is Yangchangwan char>Meihuajing char>Shenfu char.In-situ study of heating stage microscope shows that with the progress of char-CO2 gasification,most of char particles react with CO2 as shrinking particle mode,and the particle reaction form changes from shrinking particle mode to shrinking core mode at high carbon conversion level.Additionally,it can be found from the results of shrinkage ratio variation of the particle projected area during gasification that Yangchangwan char shows the largest shrinkage area when undergoes the same reaction time,followed by Meihuajing char and Shenfu char.The difference in gasification reactivity is mainly attributed to the difference of physicochemical properties of chars.i.e.,Yangchangwan char shows the largest specific surface area and the total contents of K,Na and Ca and the lowest order degree of carbon structure,followed by Meihuajing char and Shenfu char.