不同密度煤粉的矿物质分布与燃烧特性研究

A Study of the Mineral Distribution and Combustion Characteristics of Pulverized Coal of Different Densities

用重液浮选将一种烟煤分为高（〉2．0g／cm^3）、中（1．4～2．0g／cm^3）和低（〈1．4g／cm^3）3个密度段，利用SEM、XRD、XRF等分析方法，研究了不同密度原煤矿物分布、矿物成分、矿物粒径、灰成分、工业和元素分析及燃烧特性。结果显示：随着原煤密度的增加，工业分析显示煤中灰分含量增加，挥发分和固定碳含量减少；元素分析显示有机炭、元素氢和氮含量减小。低密度煤粉含少量内在矿物质，而中密度和高密度煤粉矿物质含量丰富。不同的是，前者含大量内在矿物质，后者则是以外在矿物质为主；3种密度原煤的粒度分布几乎相同，而其所含矿物质的粒径分布相差则很大。随原煤密度的增大，其所含矿物质的粒径增加很明显；3种密度原煤的热重曲线显示，低密度煤粉燃烧最为剧烈，随着密度增大则失重和放热都越来越弱。

Through the use of a heavy-liquid floatation,a kind of bituminous coal can be divided into three density sections,i.e.high(>2.0 g/cm3),medium(1.4～2.0 g/cm3) and low(<1.4 g/cm3).By utilizing SEM,XRD and XRF etc.analytic methods,a study was conducted of mineral distribution,mineral composition,particle diameter,ash constituents,industrial and elementary analysis and combustion characteristics of raw coal of different densities.The results show that with an increase in density of the raw coal,the industrial analysis indicates an increase of ash content in coal,a decrease of volatile and fixed carbon content.The elementary analysis also indicates a decrease of organic carbon,element hydrogen and nitrogen content.Low-density pulverized coal contains a small amount of internal mineral matter while medium and high-density pulverized coal contain an abundance of mineral matter.What differs is that the former contains a great deal of internal mineral matter,but in the latter a large quantity of external mineral matter predominates.The particle diameter distribution of the raw coal of three densities is almost identical.However,the particle diameter distribution of the mineral matter contained in the raw coal in question is very different.With an increase of the density of raw coal,the particle diameter of mineral matter contained in it will increase significantly.The thermogravimetric curves of the raw coal of three densities indicate that the low-density pulverized coal assumes a most intense combustion and the weight loss and heat release become ever weaker with an increase of density.