Investigation into the impact of coal blending on the carbon structure of chars obtained from Chinese coals during coking

The coke quality influences the performance of the blast furnace, and the final coke quality is significantly influenced by the carbon structural evolution of the coal during pyrolysis. Blending high-quality coal with low-quality coal affects devolatilization and the carbon structure during coking. By petrographic analysis, this paper investigates the impact of five coals varying in ranks from sub-bituminous to anthracite and binary blends on the carbon structure of coal char. The study's findings have shown that the vitrinite content of single coals and their blends significantly impact the carbon structural parameters of coal chars. A positive correlation was obtained between the vitrinite content and carbon structural parameters for all blends except the 35% lean coal blend. High crystallite lateral size was obtained at 1000 oC for samples with 20% and 25% lean coal blend. Also, the research results have shown that coalification rank positively impacts coal char carbon structural parameters. The vitrinite content of the blend is inversely proportional to interlayer spacing. The blends with 20%wt. of lean coal had the highest vitrinite content of 56.34 and 63.4%wt with an interlayer spacing of 0.346 and 0.343 nm, respectively, at 1000 oC.