高浓度水煤浆流变特性和稳定性试验研究

Experimental Study of High-concentration Coal-water-slurry Rheological Properties and Stability

水煤浆是由液固两相组成的非牛顿流体,流变性和稳定性十分复杂,影响因素也很多,其流变特性和稳定特性对管道输送和燃烧性能起着决定性的作用。借助于水煤浆粘度计对质量浓度为60%以上的水煤浆进行流变性测量,研究了温度、浓度和添加剂对煤浆流变性的影响,水煤浆的表观粘度随温度的升高而降低,随浓度增加而增大,添加剂的加入大大改善水煤浆的流变特性。通过对水煤浆稳定性的研究,得出了水煤浆的稳定性随浓度增加而增加,与煤种有关,适量的添加剂能改善稳定性,稳定性随温度升高而降低。从输送水煤浆总体经济角度看,水煤浆的输送温度在20-40℃为宜。

Coal-water-slurry is a kind of non-Newtonian fluid,composed of liquid-and-solid two-phase substance.Being subjected to many influencing factors,its rheological properties and stability are very complicated,and play a decisive role in pipeline transmission and combustion performance.With the help of a coal-water-slurry viscosity meter,a rheological measurement has been made of the slurry,which has a mass concentration of over 60%.The influence of temperature,concentration and additives on the rheological properties of the slurry has also been studied.The visual viscosity of the slurry will decrease with an increase of temperature and increase with an increase of the slurry concentration.An introduction of additives will greatly improve the rheological properties of the slurry.Through a study of stability of the slurry,the authors have concluded that its stability will decrease with an increase of its concentration,and is related to coal ranks.A proper amount of additives can improve its stability and the latter will decrease with an increase of temperature.As judged from the comprehensive cost-effective viewpoint of the slurry transmission,its transmission temperature at between 20 and 40 ℃ has been regarded as appropriate.