超细化煤粉表面形态分形特征

FRACTAL CHARACTERISTIC OF SURFACE STRUCTURE OF MICRO-PULVERIZED COAL

该文将合山、晋城煤分别制成4种不同粒度的常规煤粉与超细化煤粉进行了试验研究。采用英国Malvern公司的 MAM5004型激光粒度分析仪测定合山煤、晋城煤各4种不同粒径煤样的粒度分布。采用美国Micromeritics公司的ASPA2000型比表面积及孔径分布分析仪测定煤样的比表面积和孔隙。采用美国LECO公司的CHN 600型元素分析与MAC-500型工业分析仪测定的工业分析与元素分析数据。运用分形理论和等温吸附理论及燃烧原理,分析煤粉颗粒粒度对其表面结构:比表面积,孔容积,孔径分布及其燃烧特性的影响。试验研究与理论分析表明,随着煤粉粒径的减小,煤粉颗粒的孔隙中小孔的数目增多,平均孔径减小,吸附量与吸附表面积增大,表面结构复杂,表面分形维数增高,有利于煤粉颗粒的燃烧。煤颗粒的表面分形维数能很好地反映煤粉颗粒的物理结构特性,并进一步提供有效的煤粉颗粒燃烧特性信息。超细化煤粉具有复杂的表面结构和高的表面分形维数,通过超细化改变煤粉的物理结构,完善燃烧特性,证明超细化煤粉燃烧是一种具有发展潜力与前途的煤粉燃烧新技术。

The fine powder and micro-pulverized coals of four different particle sizes are taken from Heshan and Jincheng respectively. Malvern MAM5004 Laser Mastersizer made in United Kingdom analyzes particle sizes of pulverized coals. Special surface area and pore volume as well as pore diameter are analyzed by Micromeritics ASPA2000 specific surface area and pore diameter analysis apparatus made in United States. Ultimate and proximate are analyzed by LECO CHN 600 and MAC-500 made in United States. The granule effect on coal structure: specific surface area, pore surface area, pore volume and combustion characteristics are analyzed by fractal theory and isothermal adsorption as well as combustion principle. Experimental investigation and theoretical analysis has proved that the micropore, specific surface area, porosity ratio, pore volume, fractal dimension are greatly increased and pore diameter are decreased while the coal particle size decreased. Fractal dimension can give some useful information about pulverized coal physical structure and combustion characteristics. Micro-pulverized coal has complex surface structure and higher fractal dimension; its combustion characteristics can be perfected when particle size was reduced. Micro-pulverized coal combustion is new pulverized coal combustion technology of clean and high efficiency.