Interaction between dispersant and coal slime added in semi-coke water slurry: An experimental and DFT study

For the current situation that a large number of semi-coke powder and coal slime are difficult to be used efficiently in China. Preparation of high-performance coal-based slurry fuel is a new way to clean utilize the resources. In this article, the effect of dispersants on the performance of semi-coke water slurry containing coal slime was studied based on the experiments and density functional method (DFT). After adding 5 wt% coal slime, the slurry property is better when sodium lignin sulfonate (SLS) is selected as the dispersant, the viscosity of semi-coke water slurry with SLS as dispersant decreases from 850 mP.s to 530 mP.s, and the water-liberating rate decreases from 5.24% to 3.15%. According to DFT simulation results, the charge transfer of hydrogen atom of oxygen-containing unit structure is 0.55-0.74e when SLS is used as the dispersant. The adsorption energy between SLS and kaolinite (001) surface reaches -96.24 kJ.mol(-1), while that of H2O and sodium humate (SH) are only-1.84 kJ.mol(-1) and -16.81 kJ.mol(-1), respectively. The simulation results show that SLS and kaolinite have the strongest adsorption, which explains the reason why SLS is superior to SH for the preparation of semicoke water slurry added coal slime. The research on the interaction mechanism of additives in the slurry system provides a theoretical basis for the preparation of high-performance slurry fuel and the development of new chemicals agents.

Automated summary

This study investigated the effect of dispersants on the performance of semi-coke water slurry containing coal slime, finding that sodium lignin sulfonate is the optimal choice for improving slurry properties. The DFT simulation results showed that SLS has the strongest adsorption on kaolinite surface, providing a theoretical basis for the preparation of high-performance slurry fuel.