煤燃烧过程中表面结构变化的SEM图像分析

STUDY ON SURFACE STRUCTURE OF COAL DURING COMBUSTION WITH SEM ANALYSIS

介绍了SEM图像分析的多种方法 ,并讨论了各自的描述能力。利用这些方法分析煤在燃烧各阶段SEM图像。通过研究得到煤在燃烧过程中表面分形维数的变化规律 ,同时可获得表面孔的某些参数变化历程。分析表明 ,淮南低变质煤在 85 0℃燃烧过程中 ,煤焦颗粒表面的分维数有一个先变低后变高的过程 ,煤焦表面分维数在 2 2至 2 5区间内变化 ;同时孔径分布由近双曲线分布变化为近正态分布 ,孔洞加权平均形状因子增加。在研究过程中发现 ,不同的计算方法会对图像的分形维数数值产生影响 ,确定合适的计算方法是分形理论在煤燃烧领域中应用的关键。

Some kinds of methods used to analyze SEM image have been introduced All of these ways have their own describing ability Applying these methods, we analyze the SEM image of each step of char The general conclusion is that some parameters of char surface change with the burnout ratio The improvement of analysis method can give quantification information about images It was shown that fractal dimension of char particle surface fall at the first stages and then raise Range of value changes was limited from 2 2 to 2 5 Distribution of pore radii changes from near hyperbola to near normal distribution Weighed average pore shape factor raises The relationship between calculation methods with fractal dimension was reflected when three methods were used to calculated the five photographs It is important to decide which one method is suitable to calculate SEM photograph of char Compared with each other, we found Xie's method is fit to calculate SEM photograph of char