Effect of SiO₂/Al₂O₃ on fusion behavior of coal ash at high temperature

详细信息    查看全文

• 作者：Tinggui Yan^a ; ^b ; Jin Bai^a ; ^{stone@sxicc.ac.cn} ; Lingxue Kong^a ; Zongqing Bai^a ; Wen Li^a ; Jiang Xu^c
• 关键词：Coal ash ; Fusion behavior ; SiO2/Al2O3 ; Sintering rate ; Fusion range
• 刊名：Fuel
• 出版年：2017
• 出版时间：1 April 2017
• 年：2017
• 卷：193
• 期：Complete
• 页码：275-283
• 全文大小：2615 K
• 卷排序：193

文摘

SiO2/Al2O3 (S/A) in the ash content is always regarded as the key factor on ash sintering and slagging in the boiler and gasifier. However, the effect of S/A on ash fusion behavior is not clear for using improper samples and few quantified analysis of fusion process has been conducted. In this work, the effect of S/A has been investigated by ash fusion temperature (AFT) test, thermomechanical analysis (TMA) and thermal dynamic calculation. The composition of samples is designed for illustrating the effect of S/A, and excluding other factors.We investigated the fusion behavior of two groups of synthetic ashes with acid oxide (SiO2 + Al2O3) of 77% and 70% respectively. The ash fusion behavior in three different stages is influenced by S/A for different initial melts, slag formation rate, viscosity of liquid phase and then the solids left. The onset temperature of sintering stage (Ton) decreases with S/A until 2.0 and then remains stable. Ton is closely related to T10 (temperature when slag above 10%). In sintering stage, the sintering rate is influenced by viscosity of liquid slag for that the liquid phase is limited in this stage. However, in primary fusion stage the shrinking rate is dominated by liquid phase only when the slag viscosity is not high enough, so the shrinkage of ash samples with low S/A is following the trend of slag formation rate by Factsage due to the low viscosity of liquid phase formed. Besides, samples with S/A higher than 3.5 can be considered as Newtonian fluid at FT due to low solid content.