Study On The Formation Of Micro Glass Beads Influenced By The Mineral Composition During Air Staged Combustion

With the current excessive demand for electric coal in Chinese power plants,power plants mostly adopt the technology of variable coal blending to solve the problem of serious shortage of design coal.However,the change of coal blending brings about the change of mineral composition in blended coal,which will greatly change the formation and emission characteristics of micro glass beads in fly ash.Therefore,the pollution control of particles and the utilization of fly ash in power plants are also greatly affected.It is valuable to study the influence of the change of coal ash mineral composition on the formation of micro glass beads.In this study,Hegang coal and Jinjie coal were used as the research objects.The formation and particle size distribution of micro glass beads were studied by adding calcium carbonate and iron oxide to Hegang coal and mixing Hegang coal and Jinjie coal under staged combustion.A series of instruments were used to test the fly ash samples,which analyzed the morphology,formation mechanism,phase composition,particle size distribution and other characteristics of micro glass beads.First of all,this paper studies the formation of glass beads by adding different proportion of calcium carbonate in Hegang coal under staged combustion:with the increase of the adding proportion of calcium carbonate in Hegang coal,the amorphous particles in fly ash gradually become round,and the proportion of micro glass beads gradually increases.When the proportion of calcium carbonate in Hegang coal is more than 20%,a large number of micro amorphous particles begin to appear in the fly ash;the average particle size of micro glass beads in Hegang coal increases first and then decreases with the increase of the adding proportion of calcium carbonate.Secondly,this paper studies the formation of micro glass beads by adding different proportion of iron oxide in Hegang coal under staged combustion:with the increase of the adding proportion of iron oxide in Hegang coal,the amorphous particles in fly ash gradually become round,and the proportion of micro glass beads gradually increases;the average particle size of micro glass beads in Hegang coal decreases with the adding proportion of iron oxide increasing.At last,this paper studies the formation of glass beads by adding different proportion of Jinjie coal into Hegang coal under staged combustion:with the increasing adding proportion of Jinjie coal in Hegang coal,the micro amorphous particles in fly ash gradually become round,and the proportion of glass beads gradually increases;when a small amount of Jinjie coal is added into Hegang coal,the average particle size of micro glass beads in fly ash rapidly decreases.When the adding proportion of Jinjie coal continues to increase,the average particle size of glass beads in fly ash increases first and then decreases.