The mechanism of the ash fusion characteristics of gasification coke affected by SiO2/Al2O3 ratio and CaO content in blending coals

Abstract

ABSTRACT To replace the high-cost lump coals for fixed bed/moving bed gasification and broaden the utilization of the coke ovens with periodic overcapacity problems, the gasification coke with a large amount of low-rank coal and coals with high ash content has been prepared at low cost. To further understand the ash fusion characteristic of gasification coke affected by minerals in blending coals, the effects of SiO2/Al2O3 ratio and CaO content which were controlled by additive on the transformation of minerals and the ash fusion characteristics were investigated. The increase of SiO2/Al2O3 ratio and CaO content resulted in the decrease of ash fusion temperatures of coke, due to the inhibition of the formation of minerals with high melting point (such as mullite and hercynite) and the enhancement of the formation of low-temperature eutectic systems. The ash fusion characteristics of gasification coke affected by coal blending were dominated by the SiO2/Al2O3 ratio and CaO content in blended coal. The variation of ash fusion characteristics of gasification coke affected by coal blending could be well explained by the mechanism of the ash fusion characteristics of gasification coke affected by the SiO2/Al2O3 ratio and CaO content controlled by additional minerals.