The effect of K2O in coal and biomass ash on ash fusibility

Based on ash fusion temperature(AFT)tests and thermochemistry simulations of coal and biomass ashes,the effects of K2O in different ash compositions on ash fusibility are explored. Thermodynamic database FactSage 7.0 was employed to simulate the ash melting process and make equilibrium calculations in order to provide an insight mechanism of the effect of K2O on ash fusibility. The existence of some minerals predicted by FactSage calculation is also proven by XRD results. The results show that the effect of K2O on ash fusibility is influenced by the contents of other elements in ash,such as Si,Al and Ca. For coal ash with relatively low CaO content,adding K2O in ash in a proper amount can reduce initial deformation temperature,softening temperature,and hemispherical temperature,while having little influence on flow temperature. For coal ash with high CaO content,adding K2O in ash in a proper amount can reduce all of the four ash fusion temperatures. For biomass ash,the ash fusion temperatures could be reduced by increasing the content of K2O,but only when the content of K2O is lower than 30%. © 2016, Chemical Industry Press. All right reserved.