TY  - EJOU
AU  - Xie, Fei 
AU  - Huang, Bin 
AU  - Yang, Huijun 
AU  - Shen, Guoxin 
AU  - Zhou, Ying 
AU  - Liu, Wanli 
AU  - Meng, Tingting 
AU  - Jing, Yunhuan 

TI  - Effect of Coal Gangue Addition on the Reaction Characteristics and Ash Melting-Flow Properties of High-Alkaline Coal
T2  - Energy Engineering

PY  - 
VL  - 
IS  - 
SN  - 1546-0118

AB  - The gasification of high-alkali coal from Xinjiang in an entrained flow gasifier is prone to problems such as ash deposition, slagging, and equipment corrosion. In this study, the formulated blended coal (FPM) was selected as the high-alkali raw material, while typical coal gangue from the Qingshuiying coal mine (QSY) was used as the experimental sample. The thermogravimetric analysis and kinetic calculation methods were employed to systematically investigate the effect of adding 0 wt%, 0.5 wt% and 1.0 wt% QSY on the FPM char-CO<sub>2</sub> gasification reaction characteristics at 900–1200°C. Combined with various characterization methods, the mechanisms by which QSY addition affects the ash fusion temperature, mineral phase transitions, slag viscosity-temperature characteristics, and crystallization behavior of coal ash were elucidated. The results of the reaction characteristics showed that increasing the temperature significantly promotes the gasification reaction rate. Compared to a reaction time of 83 min at 900°C, the reaction times at 1000, 1100, and 1200°C were shortened to 30 min, 6.0 min, and 5.0 min, respectively. At the same temperature, the carbon conversion rate (<i>X</i>) and reactivity index (R<sub>0.9</sub>) of coal samples with QSY addition are lower than those of FPM, and both <i>X</i> and R<sub>0.9</sub> continuously decrease when the QSY addition increases from 0.5 wt% to 1.0 wt%. Compared with the average apparent activation energy (E<sub>av</sub>) of FPM (115 kJ/mol), the E<sub>av</sub> values for 0.5 wt% and 1.0 wt% QSY addition are reduced to 102 kJ/mol and 108 kJ/mol, respectively. Ash fusion behavior studies show that with increasing QSY addition, the ash fusion temperatures (AFTs) first increased significantly and then the rate of increase slowed down. At 0.5 wt% and 1.0 wt% QSY additions, the AFTs increased by approximately 40°C and 10°C, respectively. At 0 wt% and 0.5 wt% additions, mineral crystallization was strong, showing typical crystalline slag characteristics. When increased to 1.0 wt%, mineral precipitation was suppressed, melt homogeneity improved, the viscosity-temperature curve became flatter, and the slag type transformed from crystalline slag to glassy slag. In the 1000–1100°C range, the main mineral phases of coal ash were SiO<sub>2</sub>, CaSO<sub>4</sub>, CaSiO<sub>3</sub>, sodium pyroxene (NaAlSi<sub>2</sub>O<sub>6</sub>) and anorthite (CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>). When the temperature was raised to 1200°C, QSY promoted the formation of sodium pyroxene and anorthite and refined the grain size. At 1300°C, a new phase, leucite (KAlSi<sub>2</sub>O<sub>6</sub>), was generated, and crystals evolved from rod-shaped to flake-needle-shaped and cubic-shaped, further weakening the skeletal crystallization effect. At 1400°C, the samples underwent complete amorphous transformation.
KW  - High-alkali coal; gasification reaction; ash fusion characteristics; mineral evolution; amorphous phase transformation

DO  - 10.32604/ee.2026.086657