污泥与石油焦成浆絮凝结构及稳定性机理研究

发布时间：2018-01-01 11:28

本文关键词：污泥与石油焦成浆絮凝结构及稳定性机理研究　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：城市污泥是城市生活污水处理过程中产生的固体废弃物,对生态环境产生巨大的污染与破坏。石油焦是石化工业延迟焦化装置的副产品,由于其高含硫量,直接作为燃料会加重锅炉脱硫负荷,高硫石油焦的高效、清洁利用成为能源领域关注的热点问题。将城市污泥与石油焦共成浆气化,可以利用污泥絮凝结构提高水焦浆的稳定性,同时可节约污泥脱水处理所需的热量。但污泥与石油焦共成浆浓度低,不能大规模工业应用,且共成浆过程中两者相互作用机理有待深入研究。本文考察两种改性剂和污泥添加量对泥焦浆流变特性、稳定性、成浆浓度和Zeta电位的影响。利用旋转粘度计和转矩流变仪,建立浆体的稳定性理论模型,首次定量计算出泥焦浆的空间结构强度。借助SEM-EDX、红外光谱分析等方法,深入探讨了污泥改性对泥焦浆流变性和稳定性的作用机理。借助聚焦光束反射测量仪(FBRM)研究了污泥与石油焦颗粒在共成浆过程中的相互作用机理。首先,选用Fe2(SO4)3和Ca(OH)2对污泥进行改性处理,改性剂的加入降低了浆体的粘度。随着改性剂添加量的增加,浆体带电量减小,颗粒间静电斥力减小,浆体稳定性降低,析水率增大。综合考虑泥焦浆的流变性和稳定性,确定Fe2(SO4)3和Ca(OH)2改性剂的最佳添加量分别为污泥质量的3%和5%。加入污泥后,泥焦浆的最大成浆浓度为62%,污泥改性处理后最大成浆浓度有所提高。其次,建立了泥焦浆空间结构强度理论模型,研究发现剪切泥焦浆时的单位质量能耗约为剪切水焦浆时的2-3倍,污泥能够显著提高水焦浆的稳定性。污泥的加入提高了浆体的触变环面积,且触变环面积反映出的浆体稳定性规律与两种理论模型结论相一致。SEM-EDX分析结果表明,污泥絮体包裹石油焦颗粒形成具有一定强度的空间网状结构,同时污泥中-OH基团、-NH基团及-CH基团形成的氢键通过键合作用,使得复合焦粒结合成稳定结构,从而增强浆体的稳定性。最后,借助FBRM在线分析泥焦浆的粒径分布和颗粒数在共成浆过程中的变化规律。研究发现,污泥絮体与石油焦颗粒絮凝结合成大颗粒,因此浆体中大颗粒数增大,小颗粒数和总颗粒数均减少。大粒径絮凝颗粒相互连接,形成稳定网状结构,阻止石油焦颗粒沉降,从而提高浆体的稳定性。颗粒间通过链环和链尾作用形成聚合物,具有一定的抗剪切强度。剪切力增大,浆体的平均粒径减小,然后达到对应转速下浆体的絮凝和解絮凝的动态平衡；当剪切力恢复时,由于少部分絮体结构被破坏,无法实现重絮凝,因此浆体中总颗粒数增加,平均粒径减小。
[Abstract]:Municipal sludge is a solid waste produced in the treatment of municipal domestic sewage, which causes huge pollution and damage to the ecological environment. Petroleum coke is a by-product of delayed coking plant in petrochemical industry, because of its high sulphur content. Direct use of fuel will increase the boiler desulphurization load, high efficiency of high-sulfur petroleum coke, clean utilization has become a hot issue in the field of energy. City sludge and petroleum coke co-slurry gasification. The sludge flocculation structure can be used to improve the stability of water coke slurry and to save the heat needed for sludge dewatering, but the co-slurry concentration of sludge and petroleum coke is low, so it can not be applied on a large scale. And the mechanism of interaction between the two in the process of co-forming needs to be further studied. This paper studies the rheological characteristics and stability of two modifiers and the amount of sludge added to sludge coke slurry. The influence of slurry concentration and Zeta potential. The theoretical model of slurry stability was established by means of rotary viscometer and torque rheometer, and the spatial structure strength of slurry was quantitatively calculated for the first time with the help of SEM-EDX. Infrared spectrum analysis and other methods. The mechanism of sludge modification on the rheology and stability of mud coke slurry was discussed. The interaction mechanism between sludge and petroleum coke particles in co-slurry was studied. Using Fe2(SO4)3 and Ca(OH)2 to modify the sludge, the viscosity of the slurry was reduced with the addition of modifier, and with the increase of the amount of the modifier, the electric quantity of the slurry decreased. The electrostatic repulsion between particles decreases, the stability of slurry decreases, and the rate of water evolution increases. The rheological properties and stability of mud coke slurry are considered synthetically. The optimum addition amount of Fe2(SO4)3 and Ca(OH)2 modifier is 3% and 5 of sludge quality respectively. After adding sludge, the maximum slurry concentration is 62%. After sludge modification, the maximum pulp concentration was increased. Secondly, the theoretical model of the spatial structure strength of sludge coke slurry was established, and it was found that the unit mass energy consumption of shearing mud coke slurry was about 2-3 times of that of water coke slurry. Sludge can obviously improve the stability of water coke pulp, and the area of thixotropic ring of slurry can be increased with the addition of sludge. The results of SEM-EDX analysis show that the stability of slurry reflected by thixotropic ring area is consistent with the conclusion of two theoretical models. The sludge floc encapsulated petroleum coke particles formed a spatial network structure with a certain strength, and the hydrogen bonds formed by the -OH group and the -CH group in the sludge were used through bond cooperation. The composite coke particles are combined to form a stable structure, so as to enhance the stability of slurry. Finally, the particle size distribution and particle number of mud coke slurry are analyzed on line by FBRM. Sludge flocculation combined with petroleum coke particles to form large particles, so the number of large particles in the slurry increased, the number of small particles and the total number of particles decreased. The large size of flocculating particles connected to each other, forming a stable network structure. The stability of slurry can be improved by preventing the settling of petroleum coke particles. The polymer formed by the interaction of chain ring and tail chain between particles has a certain shear strength. The average particle size of slurry decreases with the increase of shear force. Then the flocculation of the slurry and the dynamic equilibrium of flocculation are achieved at the corresponding rotational speed. When the shear stress is restored, because a few floc structures are destroyed, the heavy flocculation can not be realized, so the total particle number in the slurry increases and the average particle size decreases.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE626.87;X703

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