【作者】 袁军；

【导师】 范浩杰；

【作者基本信息】 上海交通大学 ， 热能工程， 2009， 硕士

【摘要】 随着城市的发展,污水污泥对环境的污染问题越来越凸现出来。污泥混合焚烧或干化焚烧等处理效果非常彻底的方法逐渐成为污泥处理的主流技术。在众多的污泥热处理方法中,转筒式干燥法由于设备构造简单、运行调节方便、处理效果好等优点,非常适合我国目前的国情。因此自行设计了污泥转筒式直接干燥机及给料机、热风炉等各种配套设备,以燃烧天然气得到的高温烟气为热源对污泥转筒式直接干化技术进行了研究。试验设备可将原本含水率为80%左右的湿污泥干化到含水20～40%,每小时处理量可达50kg/h;转筒整体的水平倾角可调,转筒转速可调,转筒干燥机筒体轴心处有搅拌轴且转速可调,给料机可调节给料速度且保持给料速度稳定。以含水率大小为评判标准,可对上述参数进行组合得到各种工况以研究各参数对含水率的影响。试验结果表明,在不同的水平倾角下,含水率均随着搅拌轴转速的增大而减小,随着给料速度的增大而增大;当水平倾角为5°时,含水率随着转筒转速的增大先减小后增大,即存在一个最佳转速使含水率达到最低。之后又更换了一种污泥重复上述的试验,试验结果依然符合上述的规律,表明本试验设备对于处理不同种类的污泥具有很好的适应性。由于无法对干化污泥颗粒粒径、污泥停留时间、转筒式干燥机出口烟温等重要参数进行准确的试验测量。因此,利用计算机语言并结合相关的数学方法建立了数学模型,对干燥设备进行数值模拟。通过比较试验结果和计算结果后得出,在转筒转速和给料速度对含水率的影响方面,两种结果显示的规律性非常相似;得到的粒径数据也非常接近试验的近似测量值。在研究不同转速(不同给料速度)对含水率的影响时,不同转速(不同给料速度)下的曲线具有清晰的规律一致性,由此可以断定当转速(给料速度)处于某个试验为涉及的中间值时,其影响情况也符合已知的规律。同时还获得了很多无法用试验来验证的工况下的干化结果数据。不足之处是出口烟温的试验测量值和数值计算值差异比较大,其原因是多方面的。由于理论知识的限制,未能为搅拌轴建立相应的模型,这一差异可能是造成某些数据误差较大的重要原因。更多还原

【Abstract】 Along with the development of modern city, municipal sewage sludge becomes more and more harmful to the environment. The main and most popular methods currently are“drying-combustion”or“mixed combustion”methods. Rotary drying was wildly applied in developed countries in their early disposal periods, so it is the suitable method for the practical situation of China. So we design the rotary drier, sludge feeder, air heating furnace and other auxiliary devices and dry the sludge in rotary drier by hot flue gas which gotten by burning natural gas.The drying devices designed by ourselves can deal 50kg sludge(moisture is 80%) per hour, the moisture of the dry sludge are 20%~40%; the horizontal obliquity is alterable, the rotate speed of mixer shaft in the center of the rotate drier and the rotary drier are alterable; the speed of feeding sludge is also alterable. Setting the moisture as the assessing standard and combining the parameters mentioned above, we carried out the pilot test. The results of the test indicated that moisture decreased with the increasing of mixed shaft’s rotate speed, decreased with the increasing of feeding sludge speed; when the horizontal obliquity is 5°, moisture decreased and then increased with the speed of rotary drier’s increasing, it means a optimal speed under which moisture could be lowest is existed; when the horizontal obliquity is 2.5°, moisture decreased continuously with the increasing of rotary drier’s speed. After the pilot test, we changed another kind of sludge and repeated the process above and then got the similar discipline. It indicated that the device we designed has an excellent suitability to different kinds of sludge.For the limitation of the test condition, we can’t research more parameters, for example, the dry sludge grain size, average remaining time, the outlet temperature of drier outlet and so on. So by utilizing the computer languages and interrelated mathematics knowledge, we completed a mathematical model to simulate the rotary drier and compared the calculating results with the test results. The comparison showed that the relationship of moisture and rotary drier and feeding sludge speed the calculating results gave were very similar with the test results gave. We got the proper grain size of dry sludge at the same time. The most obvious difference between the tow results came from outlet temperature. This result was caused by many reasons, and the main reason may be that we failed to simulate the mixed shaft which is significant to the moisture in the model for limitation of the model theory.更多还原