Influence of Polycarboxylate Dispersants with Different Molecular Structures on the Performance of Coal Water Slurry

Polycarboxylate dispersants have variable structures and can be designed according to practical needs. Further study on the influence of molecular structures on the performance of coal-water slurry (CWS) has vital significance. A variety of polycarboxylate dispersants was designed and synthesized with different monomers. The performance of each dispersant for the low-rank China CWS (i.e., Shenfu coal) was evaluated. Results showed that sodium p-styrene sulfonate (SSS) was the most efficient monomer with better adsorption performance on the surface of coal particles and lower apparent viscosity (i.e., mole ratio of SSS and acrylic acid (AA) sodium 65:35, CWS concentration 63 wt%, dispersant dosage 0.5 wt%). Polyethylene glycol acrylate (PA) was also effective. In addition, 5 wt% cationic monomer methyl acryloyl oxygen ethyl trimethyl ammonium chloride (DMC) was introduced into the structure. The polycarboxylate dispersant with optimal molecular structure was applied in Shenfu coal. The performance of water slurry could meet the national standards well (i.e., apparent viscosity 920 mPa · s), displaying good rheological property and stability.