国内典型市政污泥理化特性和干化特性研究

Physical and chemical characteristics and drying characteristics of municipal sludge in Hangzhou

为探索有效的城市生活污水污泥无害化和资源化利用途径,以杭州市6个典型净水厂产生的市政污泥样品为原料,进行基本理化特性分析,并对国内典型的污泥干化设备进行比选,推进污泥干化焚烧技术路线实施。首先,对污泥样品进行工业、元素、热值、重金属含量、pH值和主成分进行分析,并采用热重红外等方法对干化污泥的燃烧特性进行分析。实验结果表明,干化污泥发热量为7000~12000 J/g、灰分为10%~30%、挥发分为7%~14%;XRD分析说明硅、钾、钠等元素以石英、钾长石、钠长石等形式存在;热重分析结果说明:污泥在150℃时挥发分开始析出;在干化机型的选择上,桨叶式蒸汽干化工艺和圆盘式干化工艺技术成熟、运行方便灵活,维护简单,经济效益高,相比于转鼓干化工艺和流化床干化工艺适用于市政污泥干化;干化时尾气主要气体组分包括水、氨气、甲烷、丙烷、甲酸等;干化后的污泥粒径分布在0~100μm之间。

In order to explore an effective way for harmless and resource-based utilization of municipal sewage sludge,the basic physical and chemical characteristics of municipal sludge samples from six typical water purification plants in Hangzhou were analyzed,and domestic typical sludge drying equipments were compared and introduced to the implementation of sludge drying and incineration technology.Firstly,the industrial and elemental components,calorific value,heavy metal content,pH value and principal components of sludge samples were analyzed,and the combustion characteristics of dried sludge were analyzed by TGIR.The experimental results show that the calorific value of dried sludge is 7000~12000 J/g,the ash content is 10%~30%,and the volatile content is 7%~14%;Results by XRD analysis show that silicon,potassium,sodium and other elements exist in the form of quartz,potassium feldspar,albite and so on,results by thermogravimetric analysis show that the volatile begins to separate out at 150℃.Compared with drum drying and fluidized bed drying technology,the paddle steam drying and disc drying technology are more mature,convenient and flexible for operation with less maintenance cost and higher economic benefit,more suitable for municipal sludge drying.The main gaseous components of tail gas during drying include water,ammonia,methane,propane,formic acid,etc.,the particle size of dried sludge is between 0~100μm.