Simulation study of coal ash fusion characteristics of blended coal

The fusion characteristics of coal ash are important factors of affecting the operation stability of the liquid slagging gasifier.The high fusion point coal will make it difficult to discharge slag from gasifier,which will lead to unplanned shutdown of the gasifier.In order to apply the Zhujixi coal with high ash fusion temperature to SE gasification furnace with liquid slagging,the ash fusion characteristics of Zhujixi coal,Shenhua coal,Menkeqing coal and Zhujixi-Shenhua blended coal were studied by thermodynamic software of Factsage,including the whole liquid phase temperature,ash mineral composition and ash viscosity.The complete fusion temperatures of Zhujixi-Mengkeqing blended coal and Zhujixi-Shenhua blended coal are 1 390 ℃ and 1 400 ℃,respectively.The fusion temperature of coal blending ash is not the sum of the ash fusion temperatures of the two coals.At 800 ℃,the content of cordierite and anorthite in the two kinds of blended coal is relatively high.At 900 ℃,a small amount of spinel appears in Zhujixi-Shenhua blended coal ash.The temperature of Zhujixi-Shenhua blended coal is 1 400℃ when its viscosity is 25 Pa·s.The results show that Zhujixi-Mengkeqing blended coal can meet the temperature requirements of fly ash flowing in SE gasification furnace,but its ash viscosity is high at the normal operating temperature of SE gasification furnace and cannot be discharged smoothly.The Zhujixi-Shenhua blended coal can not only effectively reduce the ash fusion temperature,but also improve the flow type of ash and reduce the ash viscosity.Compared with the main coal Zhujixi coal,the temperature is reduced by 100 ℃ when the ash viscosity is 25 Pa·s,and the slag type is changed from " plastic slag" to " glass slag",which is suitable for SE gasification furnace.The content of cordierite and feldspar with low melting temperature is higher in Zhujixi-Shenhua blended coal.Calcium feldspar and spinel form low temperature eutectic,which is the main reason of low temperature of the blended coal ash melting.