煤焦燃烧过程中的亚观和微观形态及反应机理

通过FESEM和EBSP对煤粉在TGA、DTF和电站锅炉内燃烧过程中的亚观和微观形态及碳的含量变化的研究表明:炭的形态可分为5类:薄壁网架炭、厚壁网架炭、浅孔实体炭、实体炭和含碳矿物;同一煤样同一温度条件下炉内炭比TGA和DTF中的炭具有更大的反应比表面积;炉内炭的表面含碳量变化不大,不存在低温反应器的表面灰壳,因此,应用球形灰壳理论预报炉内煤粉的燃烧速率是值得怀疑的;亚观形态与微观形态间不存在几何分形上的自相似性.

STUDY ON THE SUBMICRON AND MICRON MORPHOLOGY AND ITS REACTIVE MECHANISM

The characteristics of submicron and micron morphology and the change in containing carbons during combustion in TGA,DTF and W-shaped power plant boiler were studied by FESEM and EBSP,it is resulted that according to the pores distribution,chars can be simply categorized into 5 classes:tenui-frame network char,crassis-frame network char,solid with shallow pores char,solid char and mineroid containing carbons;For the special coal,the char from W-shaped boiler has much more specific surface area than that from TGA and DTF at the same condition of temperature;A different char particle contains markedly a different amount of carbons,but for a special char particle, the ratio of carbon to ash is generally constant during char combustion,and it doesn't exist ash shell on the char surface.It doesn't exist the itsself similarity on fraction geometry in the range of between submicron and micron morphotype.