Ash melting behavior of coal and biomass in reducing atmosphere
ZHANG Guanjun
Abstract：In order to reveal ash melting characteristics of coal and biomass during the high-temperature thermal conversion process,the influence of biomass addition on ash melting characteristictemperatures was investigated by ash fusion temperature test and high-temperature on-line XRD analysis.The mineral phase decomposition,reduction and phase transformation were investigated,and the changes of silicate species were verified by SiO2-CaO binary phase diagram.The results show that the addition of wheat straw significantly reduces the ash melting characteristic temperatures;the softening and deformation temperature shows a monotonically decreasing trend.When the biomass mass fraction reaches 50％,the ash flow temperature and hemisphere temperature go to be the lowest value.The high silicon content of the biomass leads to a high ATF-DT value;while the high K2O content leads to a lower DT value.At high temperature range,carbonates and sulfates decomposition reactions occurre,iron oxides and sulfates are reduced to metallic iron and sulfides,simple oxides and SiO2 will form silicates.The ash melting characteristic temperature largely dependes on the amorphous material formation rate and its softening rate.
Keywords：reducing atmospherecoalbiomassash meltinghigh-temperature on-line XRD
Publication Date：2017-01-01