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

特殊气氛高温条件下表面结构和细颗粒间相互作用表征系统的开发

基本信息

批准号：
10555262
负责人：
KAMIYA Hidehiro
金额：
$ 7.81万
依托单位：
Tokyo University of Agriculture and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2001
项目状态：
已结题

项目摘要

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.

为了表征在升高和高温条件下灰粉的内聚行为的增加机制，在高温下开发了两种类型的粘合力测试系统。改性灰粉是由细纯无形的硅粉涂层制备的，并用0.5 wt％的钠和/或钾在表面上进行热处理，并确定粘性行为和变形特性。 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.由于这些共晶材料在大约800°的粒子间形成了少量的液相。在高温条件下减少液体桥力，在这项研究中开发了两种方法。一种是高温化学反应，通过在煤混合物过程中加入细煤粉和细煤粉，以在高温条件下减少这种液体桥的形成。另一种方法是将超细碳粉的涂层或用灰分添加粗糙的高岭土颗粒，以增加表面距离并降低烟灰颗粒上液相的润湿性。两种方法都可以在高温条件下降低灰分颗粒的粘附行为。