Study on effect of dispersant on semi-coke water slurry property based on quantum chemistry calculation

In order to utilize semi-coke resources efficiently and select the suitable dispersant to improve the performance of slurry prepared by semi-coke, the effects of different dispersants (sodium humate, sodium lignosulfonate, sodium dodecyl sulfonate and a self-made itaconic acid dispersant IPMS) on the pulping property of semi-coke slurry were studied. The structure parameters of dispersant and the interaction energy between semi-coke and dispersants were calculated by the software-Material Studio (MS) and compared with experimental value. The results show that the addition of dispersants can effectively reduce the surface tension of liquid and increase the electronegativity of semi-coke particles, enhancing the electrostatic repulsion between particles and making the slurry more stable. The self-made itaconic acid dispersant IPMS has a better effect on the property of semi-coke water slurry under the same preparation conditions. The apparent viscosity is 625 mP·s when the shear rate is 100 s^-1, the water-liberating rate in 7 d of slurry is only 2.38% and there is no hard precipitation. The adsorption simulation indicates that the oxygen atom of the dispersant approaches to the hydroxyl side of the semi-coke and makes charge transfer, and the order of activity of four dispersants is IMPS > SH > SLS > SDS. The interaction between IMPS and the semi-coke leads to a strong adsorption, which is consistent with the experimental results. It is proven that the performance of dispersants can be evaluated by quantum chemical calculation combined with experimental data, providing a theoretical basis for the preparation technology of slurry fuel as well as the design and development of new reagents.