Analysis of the high-temperature cohesion behavior of ash particles using pure silica powders coated with alkali metals
Analysis of the high-temperature cohesion behavior of ash particles using pure silica powders coated with alkali metals
复制标题
碱金属包覆纯硅粉分析灰颗粒的高温凝聚行为
DOI：
--
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Naito
中科院分区：
文献类型：
--
作者：
H. Kamiya;Akira Kimura;and Mayumi Tsukada;M. Naito
本文分析了高温条件下粉煤灰粘结性增强的机理。模型灰粉末由在表面上用0.5wt%钠和/或钾涂覆和热处理的细纯无定形二氧化硅粉末制备。采用新型分体式粉层抗拉强度试验机，测定了模型灰粉层的粘结特性和变形特性。对煤粉燃烧（PC）和加压流化床燃烧（PFBC）系统中收集的飞灰的粘附行为与模型灰粉样品的结果进行了比较。在800 °C以上的高温范围内，天然灰样和碱金属与纯硅微粉制备的模型灰粉样的抗拉强度和塑性断裂变形均迅速增加。结果表明，涂层碱金属与非晶二氧化硅相反应生成少量低熔点共晶物质，从而使涂层具有较好的耐蚀性。
This paper analyzes the increasing mechanism of cohesive behavior of ash powders at elevated and high-temperature conditions. Model ash powders were prepared from fine pure amorphous silica powder coated and heat-treated on the surface with 0.5 wt % sodium and/or potassium. The cohesive behavior and deformation properties of model ash powder beds were determined by using a new split-type tensile strength tester of powder beds. The adhesion behavior of fly ash collected in a pulverized coal combustion (PC) and a pressurized fluidized bed combustion (PFBC) system was compared with the results of model ash powder samples. In the high-temperature range above 800 °C, a rapid increase of tensile strength and plastic rupture deformation occurred in both the natural ash samples and the model ash powder samples prepared from alkali metal and pure silica powder. It is suggested that the coating alkali metal reacted with the amorphous silica phase and formed a small amount of low-melting-point eutectic materials, su...