褐煤中水分对油煤浆流变性质的影响

摘要

Yunnan brown coals with different moisture contents were prepared by vca uum-drying and therm ostatic and humidistatic rt eatment, and the effects of moisut re on the rheological behavior of brown coal-oil slurries were studied at ta mos pheric pressure and room temep rature(t=19.3℃, p=1.01×105 Pa).tI is found that the moistru e contents in raw cao ls have influne ces on the rheological properties of brown coal-oil slurries. The viscosity of the slurry decresa es first and thne increases with thei ncrease in moistuer .Th e moisture contentωmin at which the lowest viscosity occurs varies with shear rta es and coal loda insg .ωmin is 9.20% at the shear stress less than 44. s-1 and 7.80%at the shear stress greater than 4.4 s-1 as the coal concentration is 45.45%.ωmin becomse 7.40%at the shear stres less than 1.32 s-1 and 10.00%at the shear ts ressg reta erht an 1.32 s-1 as the coal concentration is 55.56%.The thix otropy of brown coal-oli slurries is different for different moisture conet nst, and is enhanced with the decrease in the moisture contents.Brown coal-oil slurries containing moisture of various contne ts are pseudoplastic fluid, and the moisture contne ts also have some effects on the parameters of the rheological model.%针对云南褐煤，用真空干燥脱水和恒温恒湿箱处理获得了不同含水率的褐煤，在常温常压（ t＝19．3℃，p＝1．01×105 Pa）条件下研究了褐煤含水率对油煤浆流变特性的影响。研究表明，原料煤含水率对油煤浆黏度和流变特性有一定的影响。随褐煤含水率增加，油煤浆黏度先减小后增加。油煤浆浓度不同，剪切速率不同，黏度出现最低值的含水率值wmin也不同。浓度为45．45％的油煤浆，剪切速率小于4．4 s－1时，wmin为9．20％；剪切速率大于4．4 s－1时，wmin为7．80％。浓度为55．56％的油煤浆，剪切速率小于1．32 s－1时，wmin为7．40％；剪切速率大于1．32 s－1时，wmin为10．00％。随剪切速率变化，油煤浆黏度上下行曲线之间形成滞后环，表明油煤浆体系有触变性，并且不同含水率煤浆体系触变性不同，含水率越大，触变性越明显。实验中不同含水率褐煤油煤浆都属于假塑性流体，且含水率对模型参数有一定的影响。