空气在煤灰球中的等效扩散系数的实验测定

Experimental Determination of the Equivalent Mass Diffusivity for a Porous Coal-Ash Particle

本文提出了一种测量煤焦粒燃烬时间的方法来确定空气在煤灰球中的等效扩散系数。由于煤焦粒的燃烬时间的测定较准确，因此所得之等效扩散系数较可靠。测量结果表明，空气在煤灰球中的等效扩散系数随煤中灰份的含量的增加呈单调下降的关系，并给出了它们之间的通用关系式。

A method is presented for detemining the equivalent mass diffusivity, De,of air within a porous coal-ash particle by measuring the burnout time of the coal char particle. Because the measurement of the burnout time of a coal char particle is easy and accurate, the data of the equivalent mass diffusivities so obtained should be reliable. The experimental results show the measured value of De decreases with increasing ash content, and a relationship between them is derived. Comparisons of calculated burning rates of the large char particles of high ash content with the corresponding experimental results show that the values of De obtained by this approach are reasonable.