低NO_x煤粉燃烧飞灰中漂珠特性的研究

Study on Characteristics of the Cenospheres in Fly Ashes From Low NO_x Pulverized Coal Combustion

本文以某低NO_x煤粉燃烧电厂除尘器两个不同时间段飞灰样为原料,采用湿法浮选从飞灰中分离漂珠,并对其形貌、颗粒尺寸和组成等进行了系统的分析。结果表明,低NO_x燃烧飞灰的漂珠形貌主要为规则的圆形颗粒,尺寸相对较飞灰颗粒尺寸大而且相对集中在30～80μm之间(占比约为77.6%～86.5%)。与飞灰相比,漂珠颗粒的玻璃体含量多;虽然两个飞灰样的灰成分组成差异明显,但其漂珠的灰成分组成一致,表现为颗粒中Fe_2O3含量较多,Na_2O及K_2O含量也相对较高,在低NO_x燃烧的还原性气氛下这种组成有利于降低灰熔点和黏度,形成玻璃空心微珠。

In this paper, fly ash was selected from a low NOx combustion power plant dust collector in two different periods as raw material, and was separated using float-seek method for extracting cenospheres of density less than 1.0 g·cc-1, in addition, the morphology, particle size and composition of which were analyzed. The results showed that the morphology of cenoshperes of low NOx combustion fly ash was mainly circular particles, the particle size was larger than raw fly ash, and the size of cenospheres relatively lay between 30～80 μm, accounting for about 77.6%～86.5%. Compared with fly ash, cenosphere particles contained more content of vitreous components. Although the composition of the ash components of the two fly ash samples was obvious, the composition of the cenospheres components was consistent, showing high content of Fe2O3, Na2O and K2O, and in the reductive atmosphere of low NOx combustion, it could reduce the ash melting point and viscosity which was conducive to form cenospheres.