粉煤燃烧过程的熔融煤灰在刚玉上的结渣特性

Slagging Characteristics of Molten Ash on Corundum during Pulverized Coal Combustion

采用光学显微镜、X射线衍射等方法对煤粉气流燃烧过程中在刚玉质耐火板上结渣的渣样进行了测试,并就渣样的形貌及结晶特性、渣样成分与刚玉之间的高温烧结特性进行了分析研究.结果表明,煤粉气流焦炭颗粒着火燃烧时释放出的CO使焦炭颗粒处于还原性气氛中,降低了灰渣熔融温度,增强了熔融煤灰与耐火板之间的粘结作用;耐火板中的Cr2O3和煤灰中的Fe2O3,CaO,TiO2等晶核剂在煤粉燃烧过程中对刚玉质耐火板上的灰渣结晶程度的影响明显,Al2O3对刚玉质耐火板上熔融煤灰冷却过程的成核结晶作用不明显;灰渣的结晶度较好地反映了灰渣与刚玉质耐火板的粘结作用,在焦炭颗粒着火燃烧区域,煤样I和II灰渣的结晶度最小,分别为49%和32%左右.

In order to study the slagging characteristics of corundum refractory materials during pulverized coal stream combustion, the slag samples of pulverized coal stream combustion experiments were investigated by optic microscope and X-ray diff,-action. The morphology and crystallization of slag samples, and the sintering characteristics between ash components and corundum at high temperatures were studied. The results show that the released CO during pulverized coal stream combustion makes coke granules surface combust in deoxidization atmosphere, which lowers the ash melting temperature and strengthens the interaction between molten ash and corundum; Al2O3 in ash does not improve the crystallinity of slagging samples, but Cr2O3 in refractory board and Fe2O3, CaO, TiO2 in ash enhance the crystallinity; the crystallinity preferably reflects the viscidity action between ash dregs and cortmdum combustion liners, in coke granules catching fire and combusting region, the crystallinity reduces to the minimum, which is about 49% for coal sample Ⅰ and about 32% for coal sample Ⅱ.