Study on the slurry forming performance of coal water slurry based on the analysis of coal/coke composition and structure

Considering the coal quality is a key factor affecting the performance of coal water slurry (CWS), in this research, the composition and structure of five coal samples in Xinjiang−Zhundong coal B2, B3, B5, Heishan coal (HS), Hongshaquan coal (HSQ) and Naomaohu coke (XTJ)−were analyzed, aiming to investigate the influence mechanisms of single coals and coal/coke blending on slurryability. The results showed that the HS, characterized by the aromatic carbon skeleton dominated by 2-3 rings, exhibited low oxygen content and few hydrophilic phenolic hydroxyl, carbonyl, and carboxyl groups, which contributed to its superior slurry performance compared to other coal samples. Even at a remarkably high slurry concentration of 70.98 wt.%, the apparent viscosity remained as low as 858 mPa·s. In contrast, B3 and B5 exhibited poor slurry performance due to their abundant oxygen-containing functional groups and strong hydrophilicity, which reduced free water content in the slurry. Additionally, the high content of adsorbed water indicated a thicker hydration film on coal particle surfaces, hindering dispersant adsorption. The addition of 20 wt.% HS/XTJ to B5 disrupted the three-dimensional network structure formed by clustered particles and covered the oxygen-containing functional groups. This process not only released previously encapsulated water but also reduced hydration layer thickness. Consequently, free water content increased within the slurry, enhancing dispersant performance. These effects collectively increased coal slurry concentration by approximately 2.40 wt% (reaching 59.00 wt%), reduced apparent viscosity by ∼40%, and improved fluidity to an A+ rating.