改性城市污泥—煤浆的制备及其成浆机理研究

发布时间：2018-12-29 11:38

【摘要】：本文选取王楼气煤和徐州国祯水务运营有限公司生产的脱水污泥为研究对象,充分利用污泥中含有的大量水分及其具有的热值,将污泥掺混至水煤浆中制备污泥-煤浆。本文对城市污泥进行碱改性处理后与气煤进行污泥-煤浆的制备,并研究了改性污泥-煤浆的成浆机理。通过对污泥-煤浆与水煤浆的成浆性能对比发现,污泥-煤浆的成浆浓度低,流动性差,但浆体稳定性较好;随着污泥添加量的增加,制得的煤浆由屈服胀塑性流体转变为宾汉塑性流体,成浆浓度急剧下降,当污泥添加比例为5%(污泥干燥基占煤干燥基质量的百分比)时,成浆浓度已经降至54.11%,但浆体稳定性提高。以污泥-煤浆的定粘浓度、节水率、游离腐殖酸产率为考察污泥改性效果指标,研究不同污泥碱改性条件下改性污泥-煤浆的成浆性能,结果表明在以Na OH为改性剂、改性时间1.5 h、改性剂用量为污泥干燥基质量的20%的条件下制备的污泥-煤浆的成浆性能最好,所制得的改性污泥-煤浆的成浆浓度、稳定性和流动性均有较大提高。在改性污泥添加比例为5%时,成浆浓度为57.55%,提高了3.44%。改性释放了污泥絮凝体结构中的结合水,起到了很好的节水效果,当改性污泥添加比例为20%时,其节水率高达25.76%。通过分析分散剂在煤和污泥表面的吸附机理及其动力学、改性对污泥表面性质及空间结构的影响、改性前后污泥中水分赋存状态的变化,研究改性污泥-煤浆的成浆机理。结果表明,气煤、污泥和改性污泥对分散剂的吸附符合Langmuir等温吸附模型,吸附常数KL的关系为改性污泥污泥气煤,对分散剂的饱和吸附量的大小关系为改性污泥污泥气煤。分散剂在气煤、污泥和改性污泥表面的吸附过程符合二级动力学吸附模型,表明其吸附过程主要为化学吸附,吸附速率常数k2的关系为改性污泥污泥气煤。改性增强了污泥的电负性,在吸附NSF后电负性进一步增强,增加了污泥-煤浆体系中颗粒之间的静电斥力,改善了污泥-煤浆的流动性,提高了稳定性。Na OH的强碱性使污泥絮凝体结构遭到破坏,结构变得致密,孔隙结构减少,絮凝体结构中吸附的水分被释放出来,降低了污泥中水分的结合能,结合水含量从0.96 kg water/kg DS降至0.53 kg water/kg DS,提高了污泥中水分的利用率,降低了污泥-煤浆的粘度。
[Abstract]:In this paper, Wang Lou gas coal and the dewatered sludge produced by Xuzhou Guozhen Water Operation Co., Ltd. were chosen as the research objects. The sludge was mixed into the coal water slurry to produce sludge and coal slurry by making full use of the large amount of moisture contained in the sludge and its calorific value. This paper deals with the preparation of sludge-coal slurry after alkali modification of urban sludge and gas coal, and studies the mechanism of sludge-coal slurry formation. Through the comparison of the sludge-coal slurry and the coal-water slurry, it is found that the slurry concentration is low, the fluidity is poor, but the slurry is stable. With the increase of sludge addition, the coal slurry changed from yield swelling plastic fluid to Bingham plastic fluid, and the slurry concentration decreased sharply. When the sludge addition ratio was 5% (the percentage of sludge drying base to coal dry base mass), The pulp concentration has been reduced to 54.11%, but the stability of the slurry has been improved. The slurry properties of sludge modified with different sludge alkali-modified conditions, such as the fixed viscosity concentration, water saving rate and free humic acid yield, were studied. The results showed that Na OH was used as modifier. When the modification time is 1.5 h and the dosage of modifier is 20% of the dry base mass of sludge, the sludge-coal slurry has the best slurry properties, and the concentration, stability and fluidity of the modified sludge-coal slurry are improved greatly. When the ratio of modified sludge was 5, the pulp concentration was 57.55, which increased 3.44%. The modified sludge released the combined water in the flocculation structure of sludge and played a good water-saving effect. When the proportion of modified sludge was 20, the water-saving rate reached 25.76%. By analyzing the adsorption mechanism and kinetics of dispersant on the surface of coal and sludge, the influence of modification on the surface properties and spatial structure of sludge, and the changes of water state in sludge before and after modification, the mechanism of slurry formation of modified sludge and coal slurry was studied. The results show that the adsorption of gas coal, sludge and modified sludge on dispersant accords with Langmuir isothermal adsorption model, the relation of adsorption constant KL is modified sludge gas coal, and the relation of saturated adsorption amount to dispersant is modified sludge gas coal. The adsorption process of dispersant on the surface of gas coal, sludge and modified sludge is in accordance with the second order kinetic adsorption model, which shows that the adsorption process is mainly chemical adsorption, and the relation of adsorption rate constant k2 is modified sludge gas coal. The modification enhanced the electronegativity of sludge, further enhanced the electronegativity of sludge after adsorption of NSF, increased the electrostatic repulsion between particles in the sludge coal slurry system, and improved the fluidity of sludge and coal slurry. The strong alkalinity of. Na OH improved the stability of sludge flocculant structure, the structure became compact, the pore structure decreased, the water adsorbed in the flocculation structure was released, and the binding energy of water in sludge was reduced. The decrease of water content from 0. 96 kg water/kg DS to 0. 53 kg water/kg DS, increased the water use efficiency of sludge and reduced the viscosity of sludge-coal slurry.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;TQ536

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