工厂化循环水养殖中生物流化床的流化特性研究

Study on Fluidization Characteristics of Cyclo-Bio Fluidized Sand Biofilters in Aquaculture Recirculating System

为将旋转式生物流化床应用到工厂化循环水养殖的污水处理中，采用理论计算与实验研究相结合的方法，针对生物流化床的流态、最小流化速度和膨胀率与流速的关系展开研究。研究表明，旋转式生物流化床运行时处于散式流态化状态，滤料均匀分布，形成平稳、清晰的分层。滤料粒径控制在一定范围内（0．1-0．7mm），Ergun方程可较好的预测旋转式生物流化床的最小流化速度。表观水流流速与床层膨胀率的关系不受静止高度的影响。滤料的大小、密度、强度是影响流态化特性的主要参数。膨胀率随表观流速的增大呈非线性增长；滤料粒径和密度越大，达到相同流化状态所需的流速越大，陶粒是一种具有很大开发潜力的滤料。本研究为旋转式生物流化床的设计和在养殖污水处理中的应用提供一定的理论基础。

To improve the application of Cyclo-Bio Fluidized Sand Bed （CB FSB） to the wastewater treat- ment in aquaculture recirculating system, the state of flow, the minimum fluidized velocity and the rela- tionship between expansion and velocity were studied by combining theoretical calculation and experimen- tal data. The result showed that the CB FSB was in the state of particle fluidization and the particle dis- tributed uniformly. At the same time, the steady and clear layer was formed; Ergun equation can predict the minimum fluidized velocity well when the diameter of particle was controlled in the right range （0.1-0. 7 mm）; and the relationship between expansion and velocity was independent of the static height of par- ticles. In addition, the key parameters of fluidization characteristic were found to be the diameter, density and hardness of particles. This study will provide the theoretical foundation for the design, optimization and application of CB FSB to the wastewater treatment in aquaculture recirculating system.