放射性浓缩液桶内干燥过程数学模型及动态仿真

Mathematical Model and Dynamic Simulation of In-Drum Drying System for Radioactive Evaporation Concentrate

为实现放射性浓缩液最大程度减容,设计了桶内干燥系统,基于物料衡算与热量衡算,建立了干燥过程动态数学模型,考察了不同的工艺条件对系统总体运行参数的影响,预测了桶内物料质量、含盐率、理论料面高度、温度、蒸发速率等关键参数随时间的变化规律。结果表明:干燥总时长随加热功率、浓缩液含盐率、浓缩液温度、最终干燥盐分湿含率以及第一阶段单次加料体积的增大而减小;干燥初期,新物料的加入对桶内含盐率有较为显著的降低作用;提高干燥强度将降低料面高度,间接降低热能有效利用率;在典型的工艺条件下,桶内干燥系统理论干燥总时长为281.19h,平均蒸发速率为3.43kg/h,平均处理能力为4.05L/h。为桶内干燥系统设计及试验提供理论指导。

In order to achieve the maximum volume reduction of radioactive evaporation concentrate,the in-drum drying system for liquid radioactive waste processing was designed.A dynamic mathematical model of drying process has been established based on the mass balance equations and heat balance equations.The influences of process conditions on the overall operating parameters of the drying system were investigated by numerical simulation.Moreover,the variation of parameters such as weight of material in drum,salinity,charge level,temperature,and evaporation rate with time were predicted,respectively.The results showed that the total run time of the drying decreases with the increase of heating power,salinity and temperature of evaporation concentrate,moisture content of drying salt,and single charge volume of first stage,respectively.The salinity in drum decreases with the addition of new materials at the early drying stage.The increase of dry strength will reduce the hight of the material and indirectly reduce the effective utilization of heat energy.Under the typical process conditions,the theoretical time for in-drum drying is 281.19h,the average evaporation rate is 3.43kg/h,and the average processing rate of waste liquid is 4.05L/h.The results can provide theoretical guidance for design and experimental study of in-drum drying system.