Prediction of rice straw ash fusion behaviors and improving its ash fusion properties by layer manure addition

As rice straw has high levels of SiO₂ and alkali metals, which tend to form low temperature eutectics during thermo-conversion, by blending Ca-rich biomass, the ash fusion behavior of rice straw may be improved. Ash fusion behavior could not be measurable online, it can be beneficial to use a quickly measured ash composition and predict the ash fusion behavior instantly. In this study, the ash fusibility prediction of rice straw-based ash composition and the effect of Ca-containing layer manure addition on rice straw ash fusibility were investigated. Several significant correlations between ash fusion temperatures of rice straw and ash composition were identified. All the developed equations for AFTs of rice straw ash based on ash composition presented high accuracy with average absolute error < 4%. The deformation and softening temperature of rice straw increased more than 200 °C after adding the layer manure. The layer manure was beneficial for improving rice straw ash fusion characteristics and could replace chemical additives, combing the improved effect of both P and Ca on the ash fusion temperatures. Together with the improvement for the deformation, softening, hemispherical, and flow temperatures of rice straw ash, the 30% mass ration of layer manure could be optimum selection.