Scientific Studies on Coal Maceral and Ash for Development of Coal Utilization under High Temperature Conditions

为了开发高温条件下煤的利用技术，对煤颗粒在熔渣层上的着火行为、反应性、燃烧和气化行为以及反应过程中灰组分的变化进行了实验研究。阐明了这些现象与煤颗粒中显微组分和/或反应颗粒内焦炭结构的关系。因此，煤岩显微组分和煤焦结构可以作为评价煤的反应性的指标之一，而燃料比和煤种是目前评价煤反应性的主要指标之一。本研究的主要结果如下：1.煤的着火温度随煤粒中镜质组含量的增加而降低; 2.煤焦的着火温度取决于煤焦的结构。网络型煤的着火温度较低。3.反应气氛影响煤颗粒在熔渣层上的反应性。这可能是由于渣层和颗粒内部的灰之间的相互作用造成的。在还原条件下，煤灰与熔渣的结合破坏了煤粒，加速了反应速率。4.定量测定了碱金属化合物的蒸发速率，以阐明高温条件下煤灰的蒸发行为。实验中还测试了灰粒的存在对蒸发温度的影响，使灰粒起到了降低碱金属化合物蒸发温度的作用。

In order to develop the utilization technologies for coal under the high temperature conditions, the ignition behavior, the reactivity, the combustion and gasification behaviors of a coal particle on the molten slag layr and the changes of ash components during the reaction were studied experimentally. The relation of these phenomena to the maceral in coal particles and / or char structure within reacting particles was elucidated. So that the maceral and the char structures were able to be one of index to evaluate the reactivities of coal in addition to the fuel ratio and coal types currently applied as the index.The results obtained in this project are summarized as follows :1.The ignition temperature decreases with an increase of the vitrinite content in coal particles.2.Ignition temperature depends on the structure of char. The ignition temperature for coals with the net-work type becomes low.3.The reactivity of a coal particle on the molten slag layr is influenced by the reaction atmosphere. This may be caused by the interaction between the slag layr and ash inside the particle. Under the reducing condition a coal particle is destroyed by the combination of the coal ash with the molten slag, and the reaction rate is accelerated.4.The evaporation rate of pure alkali metal compounds are measured quantitatively in order to elucidate the behaviors of ash vaporization under the high temperature conditions. The effect of the existence of ash particles on the evaporation temperature is also tested, so that the ash particles act the fall of evaporation temperature of alkali metal compounds.