煤泥悬浮液流变性及其对沉降脱水效果影响的研究

发布时间：2018-04-29 19:31

本文选题：煤泥水 + 流变性　；参考：《太原理工大学》2016年硕士论文

【摘要】：煤泥水处理是我国湿法选煤厂的关键环节之一,其效果好坏直接影响选煤的其他分选及辅助工艺环节效能的发挥。煤泥水系统是由煤泥颗粒以及多种矿物与水组成的悬浮液,悬浮液的流变性不仅与分散颗粒、分散介质性质有关,还受环境条件的影响,其特性对煤泥水沉降和脱水效果有较大影响。本文主要对煤泥悬浮液流变性进行研究,分析不同条件下悬浮液流变性的变化规律,得出流变方程,并对不同类型絮凝剂条件下流变性及沉降脱水效果进行研究,得出以下结论:(1)不同颗粒性质及环境条件下,煤泥悬浮液表观粘度随剪切速率的增大而减小,具有剪切变稀特性,属塑性流体;分别用Herschel Bulkley方程、Casson方程、宾汉方程对其流变曲线进行拟合,宾汉方程拟合效果均较好,所得参数动切力可反映随剪切增大,分散颗粒由无规则运动到定向重排作用程度;(2)煤泥颗粒粒度对悬浮液流变性的影响包括粒度分布与粒径两方面,颗粒粒度分布越窄,颗粒粒径越小,悬浮液表观粘度越大;随颗粒密度减小,固含量增加,煤泥悬浮液流变性变差;煤泥悬浮液表观粘度随温度升高而降低,随水质硬度的增加而增大;(3)煤泥经双氧水氧化处理,随双氧水浓度升高,煤表面含氧官能团数量逐渐增多,悬浮液表观粘度逐渐降低;对长焰煤、焦煤、无烟煤三种变质程度煤泥悬浮液流变性进行研究,得长焰煤煤泥悬浮液流变性最好,无烟煤次之,焦煤最差,其表面含氧官能团数量长焰煤最多,无烟煤次之,焦煤最少;(4)对麻家梁长焰煤煤泥水中添加不同类型聚丙烯酰胺进行研究,分析煤泥水沉降脱水效果与流变性之间的关系,得出:非离子型聚丙烯酰胺对煤泥悬浮液流变性影响较小,且可较好改善沉降、过滤效果。其他类型聚丙烯酰胺,当添加量较小时,可改善悬浮液流变性,同时,其沉降、过滤特性较好;随添加量增大,煤泥悬浮液表观粘度显著增大,沉降、过滤特性变差。阳离子与两性聚丙烯酰胺对煤泥水作用效果相近,其流变特性及沉降、过滤特性变化规律一致,且相差不大。添加阴离子聚丙烯酰胺,煤泥水表观粘度介于非离子与阳离子之间,但过滤特性却为最差。
[Abstract]:Coal slurry treatment is one of the key links in wet coal preparation plant in China. Its effect directly affects the efficiency of other separation and auxiliary process of coal preparation. The slurry water system is a suspension composed of coal slime particles and a variety of minerals and water. The rheological properties of the suspensions are not only related to the properties of dispersed particles and media, but also affected by environmental conditions. Its characteristics have great influence on the sedimentation and dehydration effect of coal slurry. In this paper, the rheological behavior of coal slime suspension was studied, and the rheological equation was obtained by analyzing the rheological change of suspended liquid under different conditions, and the rheological behavior and sedimentation dewatering effect under different flocculant conditions were studied. The following conclusions are drawn: (1) under different particle properties and environmental conditions, the apparent viscosity of coal slime suspensions decreases with the increase of shear rate, and it is a plastic fluid with shear thinning characteristics. Respectively, the Herschel Bulkley equation is used to describe the viscosity of coal slime suspensions. The Bingham equation fits the rheological curve, and the result of Bingham equation is good, and the parameter dynamic shear force can reflect the increase of shear. The influence of particle size on rheology of suspension includes particle size distribution and particle size. The narrower the particle size distribution, the smaller the particle size and the greater the apparent viscosity of suspension. With the decrease of particle density and the increase of solid content, the rheological behavior of the slurry becomes worse; the apparent viscosity of the slurry decreases with the increase of temperature and increases with the increase of water hardness.) the slurry is oxidized by hydrogen peroxide and increases with the concentration of hydrogen peroxide. The number of oxygen-containing functional groups on coal surface is increasing and the apparent viscosity of suspension is gradually decreasing. The rheological properties of coal slime suspension with long flame coal, coke coal and anthracite are studied, and the results show that the rheological property of long flame coal slime suspension is the best. Anthracite was the second, coking coal was the worst, and its surface oxygen functional groups were the most abundant long-flame coal, the second was anthracite, and the coking coal was the least.) the addition of different types of polyacrylamide to the slurry of Majialiang long flame coal was studied. The relationship between sedimentation dehydration effect and rheology of coal slurry is analyzed. It is concluded that Nonionic polyacrylamide has little effect on rheology of coal slime suspension and can improve sedimentation and filtration effect. Other types of polyacrylamide can improve the rheological properties of suspensions when the amount of polyacrylamide is small, at the same time, its sedimentation and filtration characteristics are better; with the increase of the addition amount, the apparent viscosity of coal slime suspensions increases significantly, and the sedimentation and filtration characteristics become worse. The effect of cationic and amphoteric polyacrylamide on coal slurry is similar, its rheological characteristics, sedimentation and filtration characteristics are the same, and the difference is not significant. When anionic polyacrylamide was added, the apparent viscosity of slime water was between non-ion and cation, but the filtration property was the worst.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD94

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