Insight into the relationship between carbon structure and coke performance during coal blending coking

To address the increasing scarcity of high-quality coking coal resources and the theoretical need to improve coke quality through optimized coal blending, Hongsheng coking coal (HSCC) and Kunpeng fat coal (KPFC) were selected as primary coals, with Huangling gas coal (HLGC) and Yonghesheng lean coal (YHSLC) as blending coals. By comprehensively utilizing X-ray photoelectron spectroscopy (XPS), solid-state ¹³C nuclear magnetic resonance (¹³C NMR), high-resolution transmission electron microscopy (HRTEM), a 10 kg laboratory-scale simulated coke oven, and coke thermal reactivity analysis, the relationship between carbon structures and coke properties in different coal blending systems during the coking process from 600 to 1000°C was systematically investigated. The results showed that coal blending characteristics significantly affect the uniformity of temperature and pressure distribution within the coke oven. An excessively high proportion of gas coal impedes heat transfer toward the center, while an increased proportion of lean coal aggravates temperature non-uniformity due to reduced plasticity. The thermal properties of coke can be directionally regulated by blending. A high proportion of aromatic bridgehead carbon (X_b) and a low degree of aromatic ring substitution (δ) are conducive to increasing coke strength after reaction (CSR). Additionally, a high lattice fringe tortuosity is associated with a high coke reactivity index (CRI). The 9HS1YHS and 8HS2YHS exhibit excellent thermal properties, while 7KP3HL demonstrates a synergistic effect. This multi-scale analysis provides a theoretical basis for optimizing blending ratios and coke quality.