Agglomeration Characteristrics in Fluidized Bed of Black Liquor

The fluidized bed incineration of black liquor was carried out to investigate in a bench-scale reactor. The focus of combustion experiments was the influence of different operating conditions, such as temperature, additive dosage combustion. Defluidization resulting from agglomeration occurred in some experiments. Samples of bed material collected after experiments were characterized by scanning electron microscope (SEM), energy dispersive X-ray detection (EDX) and X-ray diffractometry (XRD). Results indicated that temperature and additive dosage had a significant influence on the agglomeration phenomenon. As the temperature increases, intensity of agglomeration was growing, and as the additive dosage increase, intensity of agglomeration increases. Examination by various analytical techniques of the agglomerates sampled during combustion suggests that the high sodium content in sinters. In the combustion process, alkali metal salts can form low melting point eutectics NaCl-Na(2)CO(3)-Na(2)SO(4). Therefore, it is suggested that these melting alkali metal salt materials easily form the liquid phase to move to become very sticky materials that can cause very rapid defluidization of the fluidized bed when the bed temperature over 650 degrees C, eventually leading to catastrophic sintering during the high temperature combustion. Combustion under using different Al(2)O(3) additive dosage was also tested. As expected, it can be effective to reduce the agglomeration problem. Moreover, fluidization h trait of the bed material was still stable when the black liquor was added 30% Al(2)O(3) at 750 degrees C.