Study on the slurrying mechanism of coal water slurry prepared from coal gasification wastewater

Abstract

AbstractThe coal gasification process produces a large amount of wastewater which is seriously polluted and difficult to biochemically treat. The regasification of coal water slurry produced from gasification wastewater meets the requirements of clean and efficient use of energy and the concept of circular economy. In this paper, the slurryability of coal water slurry prepared with gasification wastewater was measured, and the influence mechanism of organic matter, metal ions, and ammonia nitrogen components in coal gasification wastewater on slurryability has been studied. Results show that (a) Coal water slurry can be prepared with gasification wastewater, and the composition of wastewater has a great influence on the slurryability. (b) Phenols and alcohols in wastewater are not conducive to slurryability, while urethane in wastewater is beneficial for slurrying. (c) K+ and Na+ in wastewater have little effect on the slurryablity even in high concentration, while Mg2+ and Ca2+ have basically no effect on the slurryability under the concentration range of coal gasification wastewater. However, Fe3+ has a negative effect and Cu3+ has a positive effect on the slurryability at low concentrations. (d) Ammonia nitrogen can affect the slurryability of coal water slurry by affecting the pH of the solution. NH4OH solution is alkaline, which is conducive to slurrying, while (NH4)2SO4 and NH4Cl solutions are acidic, resulting in poor slurryability of coal water slurry.