Preparation of good fluidity coal water paste based on the modified compartment stacking theory

ABSTRACT

Coal water paste (CWP) is a mixture of pulverized coal and water with a mass concentration of more than 70 wt%. CWP has a higher coal concentration than traditional coal water slurry (~60 wt%), so it can significantly improve the efficiency of gasification and combustion. However, the preparation and rheology of paste is extremely complicated due to its high concentration and material complexity. In this paper, to obtain the preparation method of CWP which could meet the engineering demands, the effects of coal particle size distribution, grading ratio, and type and amount of dispersant on rheology of CWP are investigated. Based on the modified compartment stacking theory, the improved preparation method of CWP has been proposed, which introduces the influence of coarse particle shape. The particle size ratio of coarse and fine particles is about 12, the particle size ratio of fine and ultra-fine particles is about 5, the optimal three-peak grading ratio is 6:1:3. The preferred dispersant is pure naphthalene dry powder (PNDP), and its addition amount is 1.4 wt%. The flow grade of CWP (71 wt%) could reach A without any other modifications or treatments.

KEYWORDS:

• Coal water paste
• fluidity
• particle size ratio
• apparent viscosity

Acknowledgements

This work was funded by the National Natural Science Foundation of China (22378114), Key Research and Development Program of Autonomous Region (2023B01013), Fundamental Research Funds for the Central Universities.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the Fundamental Research Funds for the Central Universities Key Research and Development Program of Autonomous Region [2023B01013]; the National Natural Science Foundation of China [22378114].