污泥流化床焚烧过程中磷的富集机理

发布时间：2019-06-18 11:15

【摘要】：污泥作为污水处理的副产物富含大量的磷,不同形态的磷生物可利用性不同,磷灰石磷生物可利用性高。焚烧可以实现污泥减量化和无害化的同时实现磷的富集,因此本文集中研究焚烧过程中磷的富集及迁移转化行为。本文在循环流化床焚烧的基础上,利用SMT方法,结合X射线衍射(XRD)、差示扫描量热法(DSC-TG)和扫描电镜(SEM-EDS)分析,明晰污泥焚烧过程磷的富集及迁移转化机理。实验结果表明,温度和CaO可以实现磷的富集同时有利于非磷灰石磷向磷灰石磷转化。总磷随着温度的升高先升高随后降低,在850oC时达到最大值61.31mg/g。在950oC以CaO为添加剂时,磷灰石磷占总磷比例达到92.23%。结合差式扫描量热和X射线衍射,磷酸铝和CaO在675-850oC时先后生成Ca2P2O7、CaHPO4和Ca3(PO4)2。在850oC温度下,89.29%的磷富集在底灰上,5.61%的磷分布在飞灰上,且其主要是磷灰石磷。磷灰石磷随飞灰粒径的增加而增加,非磷灰石磷表现出相反的趋势,当粒径小于37.5μm时其含量逐渐趋于稳定。通过热力学计算表明,焚烧过程中磷与金属离子的结合顺序是Ca2+Mg2+Al3+Fe3+,同时950oC磷酸铁的挥发导致了总磷的降低。通过本文研究,得到污泥热处理过程中磷的富集机理,为生产过程磷污泥的无害化以及磷资源化回收提供理论技术支持。
[Abstract]:Sludge as a by-product of sewage treatment is rich in a large amount of phosphorus, different forms of phosphorus biological availability is different, apatite phosphorus biological availability is high. Incineration can realize sludge reduction and innocuity at the same time realize phosphorus enrichment, so this paper focuses on the enrichment, migration and transformation of phosphorus in the process of incineration. On the basis of circulating fluidized bed incineration, the mechanism of phosphorus enrichment, migration and transformation during sludge incineration was clarified by SMT method, X-ray diffraction (XRD), differential scanning Calorimeter (DSC-TG) and scanning electron microscope (SEM-EDS) analysis. The experimental results show that the enrichment of phosphorus can be realized by temperature and CaO, and it is beneficial to the conversion of non-apatite phosphorus to apatite phosphorus. The total phosphorus increased at first and then decreased with the increase of temperature, and reached the maximum value of 61.31 mg 路kg ~ (- 1) at 850oC. When CaO was used as additive in 950oC, the proportion of apatite phosphorus to total phosphorus reached 92.23%. Combining differential scanning DSC and X-ray diffraction, Ca2P2O7,CaHPO4 and Ca3 (PO4) 2. 2. In 675-850oC. At 850oC temperature, 89.29% phosphorus was enriched on the bottom ash and 5.61% phosphorus was distributed on the fly ash, and it was mainly apatite phosphorus. Apatite phosphorus increases with the increase of fly ash particle size, while non-apatite phosphorus shows the opposite trend. When the particle size is less than 37.5 渭 m, the content of apatite phosphorus tends to be stable gradually. Thermodynamic calculation shows that the binding order of phosphorus to metal ions during incineration is Ca2 Mg2 Al3 Fe3, and the volatilization of 950oC iron phosphate leads to the decrease of total phosphorus. Through the study of this paper, the enrichment mechanism of phosphorus in the process of sludge heat treatment is obtained, which provides theoretical and technical support for the innocuity of phosphorus sludge and the recovery of phosphorus resources in the production process.
【学位授予单位】：沈阳航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X703

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