湿污泥颗粒的流化床干燥实验及模型

Experiment and Model of Wet Sludge Pellet Drying in a Bubbling Fluidized Bed

在鼓泡流化床内以河砂为干燥介质,对单颗粒湿污泥的流态化干燥特性进行实验研究,得到了流化床温度、污泥初始水分、污泥粒径及流化速度对干燥速率的影响规律：流化床温度及污泥粒径对干燥速率的影响都呈指数规律;污泥的水分越大,干燥速率越大;在鼓泡流化床流化速度达到2倍临界流化速度以上时,充分流化,流化速度再增大（2～5倍临界流化速度）对干燥速率没有明显影响.在基本的扩散传质理论的基础上,利用实验数据回归得到湿污泥在鼓泡流化床内干燥的半经验模型,为流化床污泥干燥器的设计提供了基础数据和依据.

Drying characteristics of single municipal sludge pellet in a bubbling fluidized bed where river sand is taken as drying medium are studied for designing bubbling fluidized bed sludge dryers. The effects of drying conditions, such as bed temperature, size of sludge pellet and fluidization velocity, on drying rate are investigated. The results show that the bed temperature and size of sludge pellet affect the drying rates exponentially. The drying rate is larger with higher sludge moisture. When the bed is fluidized at the higher velocities, which are more than 2 times the minimum fluidization velocities, increasing of fluidization velocities （from 2 to 5 times fluidization velocities） can not affect the drying rate. Based on the experimental data, a semi-theoretical model of sludge drying in a bubbling fluidized bed is proposed. The research results can be reference for the design of bubbling fluidized bed sludge dryers.