TY  - EJOU
AU  - Liu, Fangqi 
AU  - Zeng, Xianpeng 
AU  - Xia, Yimin 
AU  - Wang, Zihao 
AU  - Yu, Dunxi 

TI  - Scavenging Effects of Kaolin on Fine Ash Formation during Zhundong Coal Combustion
T2  - Energy Engineering

PY  - 2021
VL  - 118
IS  - 3
SN  - 1546-0118

AB  - The previous work found that the additive kaolin could scavenge not only sodium (Na) but also calcium (Ca) and magnesium (Mg), which is the important ash fluxing agents in low rank coal combustion. Such scavenging effects of kaolin on fine ash formation were studied in the present work. A typical Zhundong coal and its blends with kaolin at dosages of 1, 2 and 4 wt% were combusted in an electrically heated drop tube furnace (DTF) at 1300°C. The fine ashes generated were collected and size segregated by a low pressure impactor (LPI). The morphology and chemical composition of fine ash were analyzed by scanning electron microscopy equipped with an energy-dispersive spectrometer (SEM-EDS). In addition, char/ash particles were sampled at various positions of DTF to elucidate how kaolin additive affected the fine ash formation process. The results further showed that apart from the scavenging of volatile Na, kaolin additive could also strongly scavenge the refractory Ca, Mg and Fe in the fine ash during Zhundong coal combustion, which transformed the sintered particles with irregular shape into melted spherical particles, and finally resulted in the considerable decrease of these elements in both PM<sub>0.4</sub> and PM<sub>0.4-10</sub> by melting and agglomeration. The close contacts between kaolin particles and coal resulted from physically mixing were a key factor responsible for the reaction of kaolin with the refractory Ca, Mg and Fe.
KW  - Zhundong coal; kaolin; fine ash; basic elements; sodium; ash deposition

DO  - 10.32604/EE.2021.014240