电厂污泥掺烧过程中元素迁移特性研究

摘要

电厂污泥掺烧的重金属元素及其他有害元素被排放到大气中,会对大气环境质量和人体健康产生不利的影响.采用X射线荧光光谱仪对厦门集美区某污泥掺烧燃煤电厂掺烧入炉煤、污泥、飞灰和底灰4种固体样品中的元素水平进行测定,分析了样品中Na、Mg、Al、Si、Ca、Fe、S、K、Ti等9种常量元素,以及P、Zn、Cu、Mn、Ni、Cr、As、Pb等8种微量元素的含量,并对元素的迁移特性进行研究.结果表明,由于污泥中元素含量较普通燃煤高,导致污泥掺烧电厂飞灰及底灰中的元素含量普遍高于普通燃煤电厂.元素在飞灰及底灰中的相对富集系数也表明微量元素更容易富集在飞灰中.通过计算元素的年挥发量发现,以气体形式较大量挥发的有害元素有:S、P、Mn、Zn、Pb、Cu、Ni、As、Cr,其中Cr及S的排放浓度超过国家标准限值.这些元素的环境风险影响需引起高度重视.%Heavy metal elements and harmful elements emission would have an adverse influence on atmospheric environment quality and human health.The elements of the samples of coal,sludge,fly ash and bottom ash collected from a coal-fired power plant burning with sludge in Jimei district,Xiamen,were analyzed and the characteristics of elements migration were studied.A total of 9 kinds of major elements (Na,Mg,Al,Si,Ca,Fe,S,K,Ti) and 8 kinds of trace elements (P,Zn,Cu,Mn,Ni,Cr,As,Pb) were detected by X-ray fluorescence spectrum.Compared with the pure coal-fire power plant,the concentrations of elements in the coal-fired power plant burning with sludge were generally higher due to the higher element content in sludge than that of coal.The relative enrichment coefficients of elements in fly ash and bottom ash were calculated.The results showed that elements were more likely to enrich in fly ash compared with bottom ash.By calculating the amount of elements volatilized to the air per year,the harmful elements with large volatilization amount were S,P,Mn,Zn,Pb,Cu,Ni,As and Cr.Among these elements,the emission concentrations of Cr and S exceed the national standard,therefore,the impact of these elements on the environment should be paid attention.