摘要
针对一台燃用高熔点灰(初始变形温度大于1400℃)的水煤浆锅炉内卫燃带上(耐火材料)发生较严重结渣的情况进行了分析和实验研究对于卫燃带上不同阶段灰渣沉积的元素分析表明,卫燃带上初始阶段、中间阶段与成熟阶段沉积渣样铁和钙元素表现出富集。现场观察和扫描电镜形貌分析表明,沉积渣样并未发生熔融。晶相分析结果表明,各个阶段沉积样品的晶相组成变化不大,主要形成莫来石,长石类和部分铁的矿物质。不同温度下煤灰烧结样品的氮吸附比表面积测定表明,在低于变形温度下,煤灰尽管不发生熔融,但却会发生强烈的烧结,表现为比表面积和孔容积的降低。铁和钙在沉积表面的富集加剧了颗粒的烧结程度,为沉积灰渣颗粒不脱落提供了条件。
Analysis and experiments were carded out on one case that ash deposited on the heat-insulation layer （refractory） in one boiler burning coal water slurry with high ash fusion temperatures（AFTs）（with initial deformation temperature above 1 400℃）. Elemental analysis shows that both iron and calcium are enriched in the three samples corresponding to different stages of deposition, viz. initial, middle and mature stage respectively. In situ visual observation and scanning electron microscope （SEM） morphology indicate that no fusion occurs for the deposits; X-ray diffractometer （XRD） crystallization phase results show that there is no significant difference between each stage deposits. For each stage deposits, mullite, feldspar and some iron mineral form in the deposits. Specific surface area measurements on coal ash samples sintered at different temperatures were performed using nitrogen adsorption （N2-BET）, the results show that below the ash deformation temperature, even though no fusion occurs, the specific surface area decreases with increasing temperature, which gives the evidence that sintering does strongly occur below ash deformation temperature. The enrichment of both iron and calcium leads to strong sintering propensity of the deposited particles, and the strength developed by sintering provides forces to prevent deposits from shedding.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2008年第14期20-26,共7页
Proceedings of the CSEE
关键词
卫燃带
耐火材料
灰沉积
破碎
烧结
heat-insulation layer
refractory
ash deposition
fragment
sintering
