Development of Characterizing System for Surface Structure and Interaction between Fine Particles at High Temperature Conditions with Special Atmosphere

为了表征在升高和高温条件下产生的阿什粉末的一致行为的增加机制，在开发的高温条件下有两种类型的粘合剂力测试系统。经修改的灰粉是由精细的纯淀粉粉末涂覆和热处理的，表面上有0.5重量%的钠和/或钠，以及确定的相干行为和变形性能。在800 ° C以上的高温范围内，由于在两种天然灰样品和纯硅粉末中制备的铝合金和纯硅粉末的铝合金金属反应的快速增加，因此建议用淀粉相涂布铝合金金属反应并形成低熔点电子材料的小剂量，如K_2O.4SiO_2。自从这些电子材料形成了约800 ℃的粒子间液体相位的少量量。为了减少高温度条件下的液体桥梁力量，在本研究中开发了两种方法。一个是高温度化学反应，通过添加精细CaO粉和精细煤炭粉在煤炭燃烧过程中减少这样的液体桥形成，在高温条件下。另一种方法是使用超精碳粉末涂层或添加焦高岭土颗粒，以增加表面距离，并减少灰尘颗粒上液体相位的湿度。这两种方法都是有用的，可以减少在高温条件下的灰尘颗粒的粘合行为。

To characterize the increasing mechanism of cohesive behavior of ash powders at elevated and high-temperature conditions, two type of adhesion force testing system at high temperature were developed. The modified 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 and the cohesive behavior and deformation properties were determined. In the high-temperature range above 800 ℃, since 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, such as K_2O・4SiO_2. Since these eutectic materials formed a small amount of liquid phase at inter-particles at about 800 ℃. To reduce the liquid bridge force at high temperature conditions, two methods were developed in this research. One is the high temperature chemical reaction by the addition of fine CaO powder with fine coal powder during coal combustion process to reduce such liquid bridge formation at high temperature condition. Another approach is the coating of ultra-fine carbon powder or the addition of coarse kaoline particle with ash particle to increase the surface distance and to decrease the wettability of liquid phase on ash particles. Both approaches is useful to reduce the adhesion behavior of ash particle at high temperature conditions.