燃烧过程中孔隙变化对煤粒破碎影响的研究

破碎是煤燃烧过程中的一个复杂的物理化学过程。煤颗粒的破碎对燃烧(如煤粉的燃尽时间、飞灰粒径分布等)以及污染物的排放有很大的影响。近年来国内外一些学者通过相关研究，普遍认为破碎的发生主要是由碳的孔隙结构决定^1]，尤其是大孔孔隙率的分布；而不均匀加热引起了孔隙率的不均匀变化，当孔隙率大于临界孔隙率时破碎就有可能发生^2]。孔隙率变化的影响因素主要有：粒子热传导率、初始孔隙率分布、粒子固有的不均匀性等。

An Overview of Research Results Concerning the Impact of Pore Variation on Coal Particle Fragmentation during the Combustion of Coal

Coal particle fragmentation represents a complicated physico-chemical process during the combustion of coal. The fragmentation of coal char particles may have a major impact on the combustion of coal (for example, pulverized-coal burnout time, fly ash particle diameter distribution, etc) and pollutant emissions. As a result of the relevant studies in recent years by some academics both at home and abroad it has been generally recognized that the fragmentation process is mainly determined by the porous structure of coal char, especially by the distribution of porosity of large pores. Moreover, a non-uniform heating will give rise to a non-uniform change of the porosity. When the porosity happens to be greater than a critical one, a possible fragmentation will take place. The main influencing factors of porosity change include: the heat conductivity of particles, initial porosity distribution, the inherent non-uniformity of particles, etc.