对流受热面上准东煤灰的沾污烧结及多元组分烧结机理

Sintering of Zhundong coal ash will happen on convective heating surfaces, leading to severe growth of ash deposition and it is hard to remove. This project focuses on the fouling sintering mechanism on convective heating surfaces and in that temperature range the mechanism of multi-component sintering. The influence of several sintering factors will be quantitatively measured and analyzed, and the effect of liquid sintering or solid sintering on the convective heating surfaces will be given a conclusion based on the various ash experiments with different Na content. Then some models combined with immersed boundary method will be used for modeling the ash deposition growth. For this purpose, a thermal state fly ash deposition experimental facility with many measuring apparatus is used to rebuild the ash growing phenomenon and the fouling sintering mechanism will be interpreted. A new designed ash sphere pressure-drop sintering technique which can fulfill sintering kinetic parameters measurement and PDS together will be used to obtain sintering temperature, sintering kinetic parameters and surface free energy, etc. The quantitative data of those sintering factors will be obtained, too. The ultimate purpose is to elucidate fouling sintering mechanism of zhundong coal ash on convective heating surfaces, predict ash deposition growth and morphology, bring forward controlling measures and provide basic research data for sintering control and synthesis utilization.

准东煤灰在对流受热面上沾污时会发生烧结，导致积灰高度过度生长并难以除灰。本课题针对对流受热面上的沾污烧结机理和对流受热面所处温度区间内准东煤灰的多元组分烧结机理，定量分析多个烧结因素对于准东煤灰烧结的影响，判定对流受热面上不同程度除钠后准东煤灰的沾污烧结过程中液相烧结或固相烧结的作用，进而建立模型并与浸没边界法数值模拟相结合预测积灰生长规律。为此，本课题利用热态飞灰沉积试验台及多种测试方法，再现对流受热面上沾污烧结过程并剖析其烧结机理；设计全新的灰球压降法实现烧结动力学测量及压降法双重功能，研究烧结点温度、烧结动力学参数、表面自由能等烧结特性指标，获取各烧结因素影响的定量分析数据。最终将阐明准东煤灰在对流受热面上沾污烧结的关键机理，通过模型及模拟实现积灰生长状态预测，提出调控措施，同时为准东煤灰的控制烧结与综合利用提供基础数据。

准东煤灰在对流受热面上沾污时会发生烧结，导致积灰高度过度生长并难以除灰。本课题针对对流受热面上的沾污烧结机理和对流受热面所处温度区间内准东煤灰的多元组分烧结机理，定量分析积灰和烧结过程中的积灰生长速度、沉积率、烧结点温度等各项参数的变化规律，研究对流受热面上不同程度除钠和负载氧化物组分后准东煤灰的沾污烧结过程中液相烧结或固相烧结的作用，进而建立模型并与浸没边界法数值模拟相结合预测积灰生长规律。为此，本课题利用热态飞灰沉积试验台、烧结特性试验台、灰球压降法及多种测试方法，深入剖析对流受热面上沾污烧结过程并剖析其烧结机理；获取烧结特性指标及各烧结因素影响的定量分析数据；最终利用浸润边界法模型及模拟实现积灰生长状态预测，为准东煤灰的控制烧结与综合利用提供基础数据。