化工学报 ›› 2016, Vol. 67 ›› Issue (6): 2542-2547.DOI: 10.11949/j.issn.0438-1157.20160096

• 能源和环境工程 • 上一篇    下一篇

温度、接触压力与时间对燃煤飞灰固体桥力的影响规律

赵硕, 栾超, 由长福   

  1. 清华大学热科学与动力工程教育部重点实验室, 北京 100084
  • 收稿日期:2016-01-21 修回日期:2016-03-06 出版日期:2016-06-05 发布日期:2016-06-05
  • 通讯作者: 由长福
  • 基金资助:

    国家自然科学基金项目(51476089);高等学校博士学科点专项科研基金博导类资助课题(20120002110010)。

Effect of temperature, contact pressure and duration on solid-bridge force of coal ash

ZHAO Shuo, LUAN Chao, YOU Changfu   

  1. Thermal Science and Power Engineering Key Laboratory of Ministry of Education, Tsinghua University, Beijing 100084, China
  • Received:2016-01-21 Revised:2016-03-06 Online:2016-06-05 Published:2016-06-05
  • Supported by:

    supported by the National Natural Science Foundation of China (51476089) and the Research Fund for the Doctoral Program of Higher Education of China (20120002110010).

摘要:

在所开发的用于在高温条件下(最高使用温度可达1600℃)测量灰的固体桥力的实验系统上,研究了温度、接触压力及接触时间对燃煤飞灰的固体桥力的影响规律。结果显示,燃煤飞灰的脖颈抗拉强度与温度之间呈现出双峰分布曲线的关系。这是由于随着温度的变化,燃煤飞灰的物相状态发生改变,玻璃体成分的含量也随之变化。在温度不变的情况下,燃煤飞灰的烧结脖颈抗拉强度随接触时间和接触压力的增加而增大。

关键词: 高温, 固体桥力, 烧结, 测量, 脖颈抗拉强度

Abstract:

During the combustion process of coal, biomass or other solid fuels, the phenomenon of ash deposition is a common but serious problem is that it can seriously affect the safe and stable operation and performance of the equipment. During the ash deposition process, the adhesive behavior between different ash particles plays an important role. Solid and liquid bridge forces are two important type of adhesive force. But the studies of solid- bridge force are not enough now. An experimental system for the measurement of solid-bridge force of ash at high temperatures was designed and developed. The maximum temperature of the system was 1600℃. By using this experimental system the solid-bridge force can be measured and the effect of different temperatures, contact pressure and duration can be researched. The result indicated that the temperature dependence of the neck tensile strength development showed a bimodal distribution. It was because that the phase conditions of ash were changed by increasing temperature, resulting in the change of the content of the glassy substance. The molecular diffusion rate at the interface of the ash column was accelerated with increasing temperature. And it also accelerated the improvement of the void and the lattice defect in the neck. By increasing the contact duration, the neck tensile strength increased because the process of the improvement of the void and the lattice defect in the neck became more fully. If the duration was enough, the neck tensile strength would reach a steady state. The neck tensile strength was increased with increasing contact pressure. The high pressure made the contact between the two interface of the ash column more closely and it was conducive to accelerate the molecular diffusion rate. High temperature and contact pressure could make the neck tensile strength reach a steady state in a shorter duration. The work provided a basis to establish the model of solid-bridge force of coal ash and predict the behavior of coal ash deposition in the specific conditions.

Key words: high temperature, solid-bridge force, sintering, measurement, neck tensile strength

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