Experimental investigation of Zhundong high-calcium coal ash adhesion characteristics on metal surfaces at high temperatures

摘要

Herein, the influence of ash adhesion characteristics on the slagging of Zhundong high-calcium coal (ZDc) has been firstly investigated via a self-designed measuring instrument. The results demonstrate that the early appearance and rapid growth in adhesion strength of ZDc ash are the important reasons for its serious slagging in the furnace, and the temperature plays an important role on the adhesion between ZDc ash and metal. From 800 degrees C to 1000 degrees C, the adhesion strength of ZDc gradually increases from 1.858 to 21.725 kPa. Meanwhile, the adhesion strength could increase rapidly due to the production of more liquid phase when the temperature exceeds 1000 degrees C, and the adhesion strength is 184.933 at 1200 degrees C. The calculation results via FactSage software also indicates that molten sulfate is the main component of liquid-phase ash and the enhancement of the CaO content contributes to promote the low-temperature eutectic of gehlenite, etc., thereby enhances the strengthen of the adhesion.