Ash fusion temperature regulation mechanism of Xiangyang coal by coal blending

Abstract

The modifications in the low ash fusion temperature (AFT) of Xiangyang coal (XY) were investigated by blending it with three high AFT coals [Jincheng coal (JC), Sunjiahao coal (SJH), and Shajuzi coal (SJZ)], respectively. These three coals all improved XY AFT effectively. With the JC mass ratio varying from 0 to 50%, the AFT of XY/JC gradually increased. The AFT of XY/SJH increased significantly (0–30%), slowly (30–40%), and rapidly (40–50%) with increasing SJH content. For SJZ, the AFT of XY/SJZ increased quickly (0–30%) and very slowly (30–50%). For XY entrained-flow gasification, the appropriate blending ratios of JC, SJH, and SJZ were 40–50%, 30–40%, and 20–40%, respectively. X-ray diffraction, scanning electron microscopy, and FactSage thermodynamic calculation were applied to investigate the effects of mineral transformation on AFT. Quartz (SiO2), anorthite (CaAl2Si2O8), diopside (CaMgSi2O6), and hedenbergite (CaFeSi2O6) were detected in XY ash at 1100 °C. As the mass ratios of high AFT coals increased, the obvious increase in anorthite content led to the rise in the AFT of XY/JC; mullite (Al6Si2O13); and corundum (Al2O3) with a high melt point formed in ashes causing the increase in the AFTs of XY/SJH and XY/SJZ, respectively.