Effect of High Calcium and High Iron Coal on Ash Fusion Characteristics of Petroleum Coke during Cogasification

Entrained flow gasification provides a more efficient utilization method for high-sulfur petroleum coke. The operation temperature of the entrained flow gasifier must be above the ash fusion temperature (AFT) of petroleum coke due to the liquid slag discharge. In this work, petroleum coke was blended with high-calcium coal and high-iron coal, respectively, under a reducing atmosphere, and the variations in AFTs were recorded by an ash fusion temperature analyzer. The influence of mineral transformations on the ash fusion characteristics of blended ash was analyzed by X-ray diffraction and FactSage. The results showed that both high calcium coal and high iron coal could efficiently reduce the AFTs of petroleum coke. When the ratio of high calcium coal and high iron coal reached 60 wt %, the corresponding flow temperature (FT) of mixed ash decreased to 1225 and 1312 °C, respectively. With the content of high calcium coal increasing, coulsonite (FeV₂O₄), vanadium trioxide (V₂O₃) and nickel (Ni) with high-melting points tended to decrease, causing the decrease of AFT for mixed ash. As high iron coal was added, Ni and V₂O₃ continuously kept decreasing. In particular, the percentage of FeV₂O₄ first increased and thereafter decreased with high iron coal above 40 wt %.