摘要
污泥热干化工艺的高运行成本制约着该工艺在我国的推广。为确定污泥低温热干化的最佳效率条件,提供节约热干化工艺成本的理论基础,以北京市城市污泥为样品对低温热干化进行了模拟试验。比较了不同温度（125℃、150℃、175℃、200℃）、不同比表面积（柱形、饼形、球形）的大颗粒污泥的干化速率,并试验了有无流动气氛两种环境条件。结果表明,污泥热干化大致分为3个阶段：升速阶段、匀速阶段和降速阶段。3种形状中,饼形污泥的干化效率最好;干化效率点在125-150℃;提出了修正的Page模型,并且通过参数分析得到了低温热干化的温度效率拐点,佐证了效率点温度在140℃左右;流动气氛会进一步提高脱水效率。污泥热干化尾气释放特性一直是研究难点,用土壤中VOC的监测方法发现,新鲜污泥中的VOC能被准确监测,但经过加热干化后的尾气中的有机成分剧增,而且难以使用GC/MS定性。
The present paper is inclined to introduce a new method for increasing the thermo-dehydration efficiency in treating the grossgranule sewage sludge.As is known,it is a general research trend for further improvement of the thermo-dehydration of the sewage sludge.But in China,such a kind of research trend is still new and little has also been known largely because of its high cost to be spent on the study of the basic theoretical mechanism accounting for its application.In order to find out the basic theory accounting for the low-cost thermo-dehydration method,we have studied the optimal conditions of thermo-dehydration and conducted laboratorial experiments in a sewage sludge treating plant in Beijing.What is more,we have also conducted a model simulation research,which let us make a comparison among some four experimental conditions,such as the different specific surfaces and the same quality of the sewage sludge sample（cake,cylindrical and spherical and what with the gross particle sludge）,the blowing air and four proper temperatures（at 125 ℃,150℃,175℃ and 200℃） in thermo-dehydration tests.And,then,we have revised the Page model to simulate the thermo-dehydration experiments.All the above work has made us find that the cake sludge owns the highest dehydration efficiency and the best efficiency temperature points lying between 125-150 ℃.What is more,the revised Page model is exacdy suitable for describing the dehydration characteristic features of the gross-particle sludge.The laboratory analysis of the parameters concerned help us to find the turning point of dehydration efficiency which is around 140 ℃,at which the dehydration efficiency can be made to reach the highest point when there exists blowing air.What is more,we have also discovered that it is likely for the discharged off-gas from the sludge dehydration to lead to air pollution and prevent the normal operation of the dehydration process,though it is very difficult to find the two kinds of situation.Therefore,the method used to be n
出处
《安全与环境学报》
CAS
CSCD
北大核心
2015年第6期185-190,共6页
Journal of Safety and Environment
基金
中央高校基本科研业务费专项(12XNLJ02)
关键词
环境工程学
低温热干化
城市污泥
含水率
比表面积
environmental engineering
low-temperature thermo-dehydration
sewage sludge
moisture content
specific surface
