乏气送粉锅炉煤粉浓度软测量技术及其仿真研究

锅炉燃烧过程中，喷燃器出口煤粉浓度不均将会导致炉膛火焰中心偏斜，从而引起炉膛气流冲刷后墙及右墙，高温过热器，高温再热器出现局部超温，结焦的现象。因此准确测量各风管中的煤粉浓度并指导调节对锅炉的安全，经济运行非常重要，为此，必须寻找一种简单，高效，实用而且适合工程应用的煤粉浓度测量的方法。对于热风送粉锅炉的煤粉浓度测量，国内外做了大量的研究，并得到了工程应用。本文提出了一种乏气送粉方式下基于气固两相流理论，根据风粉混合前后压力差大小计算粉煤浓度的新方法，并在理论推导的基础上进行了仿真研究，结果表明，煤粉浓度计算值与混合压差呈很好的对应, 说明能量法理论计算公式是适用的。

Soft Technique for the Measurement of the Concentration of Pulverized coal in a Boiler with Its Pulverized coal Being Transported by Depleted Exhaust Gas and the Related Simulation Study

The non uniformity of pulverized coal concentration at a burner outlet during a boiler combustion process will lead to the skewing of a furnace flame center, thus resulting in the sweep of furnace gases onto the boiler rear wall and right wall. This, in turn, can set off a local overheating and an intensive slag formation in the high temperature superheater and reheater. In view of this, the accurate measurement of pulverized coal concentration in various flue pipes and its proper regulation play a key role in assuring the safe and economic operation of a pulverized coal fired boiler. To this end, it is essential to devise a simple, highly effective and practical for engineering use method for the measurement of pulverized coal concentration. A huge amount of research has been conducted both at home and abroad with respect to the techniques of measurement of pulverized coal concentration in boilers whose pulverized coal is transported by hot air. In this regard some cases of engineering application have been reported. The present paper focuses on an innovative method for calculating the concentration of pulverized coal, when the latter is transported by depleted exhaust gas. This method is based on a gas solid dual phase flow theory and mainly takes into account the pressure difference existing prior to and after the mixing of air and the pulverized coal. Furthermore, a simulation study has been performed on the basis of a theoretical deduction. The results of the study indicate that there exists a close correlation between the pulverized coal concentration magnitude and the pressure difference before and after the mixing of air and the pulverized coal, demonstrating the validity of the theoretical calculation formula based on the energy method.