Performance and Reaction Mechanism of a Novel Coking Binder Obtained from Low-Grade Coal

Abstract

Under the premise of ensuring the quality of coke, reducing coking/fat coal utilization is an urgent problem in the coking industry. This study prepared an extract with softening and bonding characteristics from noncaking low-grade coal by a degradative solvent extraction method. The substitution effect of coking/fat coal by the extract for coking was studied, and the effect mechanism was analyzed in detail. The results show that the caking index of the extract reached 100 and the vitrinite content reached 80%. When the extract substitution ratio is 10%, the coke quality is basically unchanged. Especially when the substitution ratio is 5%, all of the properties of coke are improved, the particle coke reactivity index (PRI) decreases by 4%, the particle coke strength after reaction (PSR) increases by 5%, and the coke microstrength index (MSI) increases by 12%. The influence mechanism model of extract addition on the strength and structure of coke was proposed. The lower softening point of the extract can broaden the plastic interval and improve the caking properties and fluidity of the blended coal, reduce the porosity of coke, and improve the order degree of the carbonaceous structure. Moreover, the highly reactive extract undergoes cross-linking reactions with coal during coking; thus, the cross-link bonds further improve the strength of the coke.