Stabilization of Highly-loaded Coal-Water Mixture by Surface Active Agents

Abstract

The highly-loaded coal-water mixture (CWM) suitable for practical use is reguired to have no settling of coal particles as well as to be highly loaded and low viscous. Thus, in this study, anionic and nonionic surface active agents possessing a dispersing power were added to CWM samples and their stabilizing ability was examined, and the following results were obtained.
1) Sodium salt of formalin-naphthalenesulfonate condensate (NSF-Na) had a great stabilizing effect at a molecular weight of 7500 or more to keep a Saxon Vale coal CWM stable for 14 d.
2) S odium salt of polystyrenesulfonate (PSTS-Na) had a great stabilizing effect at a molecular weight of 50000 to 120000 to keep a Saxon Vale coal CWM stable for 21 d.
3) When the pH value of CWM samples was set from 9 to 10 by the combined uses of NSF-Na and NaOH, a Saxon Vale coal CWM remained stable for 28 d.
4) When the agent produced by the addition polymerization of prop ylene oxide (PO) and ethylene oxide (EO) to polyethylenimine (PEI) was used, its stabilizing effect was higher as its molecular weight per the side chain increased. It kept a Saxon Vale coal CWM stable for 28 d at its best. The ethylene oxide content in its side chain was preferable to be 80% to 90%.
5) The stabilizing effect of NSF-Na tended to vary depending on the type of coal, while that of the adduct of PEI with PO-EO was invariable with any type of coal.