煤催化气化条件下不同煤种煤灰烧结行为研究

选取9类典型煤种,利用压差法测定烧结温度的实验装置,结合灰渣的XRD分析结果,考察了添加K基碱金属催化剂、不同煤种灰成分对烧结温度的影响。结果表明,碳酸钾催化剂的添加,明显降低高铁钙含量的WJT煤的灰熔点及烧结温度,碱金属K化合物极易同煤中Fe、Ca的矿物质反应生成低温共融物进而加剧煤灰的熔融结渣。不同煤种烧结温度的差异与煤灰中硅、铝、铁、钙含量密切相关。铝、硅含量高的煤灰烧结温度较高,而铁、钙含量高的煤灰烧结温度相对较低。碱金属K催化剂的添加加剧了煤灰的烧结结渣,而钙、铁的存在会加速硅铝酸盐间的反应生成低温共融物进而加速灰熔融。各煤种烧结温度的变化与其灰成分在CaO-SiO₂-Al₂O₃、FeO-SiO₂-Al₂O₃三元相图上的位置相吻合。

Sintering behavior of different coal ashes in catalytic coal gasification process

A homemade pressurized pressure-drop measuring device and X-ray diffractometer (XRD) analyzer were used to determine the effects of alkali catalyst addition and different chemical compositions of nine kinds of coal ashes on the ash sintering temperature. The results show that the sintering temperature of WJT coal ash containing higher Fe and Ca compositions declines markedly after adding potassium carbonate catalyst. K minerals react easily with Fe and Ca minerals to produce low-melting-point eutectics, which accelerates the sintering and agglomeration. The sintering temperatures of various coal ashes are closely related to the contents of Si, Al, Fe and Ca in coal ashes. The sintering temperatures increase for the coal ash with higher content of silicon and aluminum, but decrease for the coal ash with higher content of calcium and iron in ash. Adding K catalyst can promote the slagging by forming eutectic matters, especially in the presence of calcium and iron. The three-element phase diagrams of CaO-SiO₂-Al₂O₃, FeO-SiO₂-Al₂O₃ could explain the sintering temperatures variance.