木质素悬浮液管式降膜蒸发传热研究

Heat transfer of lignin suspension tubular falling film evaporation

管式降膜蒸发器由于具有传热系数高、传热温差小等优点,已应用于多个工业领域,对管式降膜蒸发器的研究也成为近年来传热技术领域的一项重要课题。文中设计了一套管式降膜蒸发装置,以木质素悬浮液为工质,对影响降膜蒸发传热的因素进行了实验研究,通过冷膜实验测试了所设计的筛板分布器的性能,得出筛板分布器能较好地使物料在换热管内壁上成膜,性能良好。通过传热实验确定了在一定范围内的喷淋密度、热通量、传热温差、悬浮液的固含量(质量分数)对蒸发侧传热系数的影响,得到了适用于一定条件下的蒸发侧传热系数关联式,该式计算值与实验值的误差在±10%以内。

Owing to the advantages of high heat transfer efficiency, small heat transfer temperature differences ere, tubular falling film evaporator is used in many industrial fields, and the study of tubular falling film evaporator becomes an important subject of heat-transfer technology in recent years. A set of tubular falling film evaporation equipment was designed. With lignin suspending liquid as a working fluid, an experimental study on the influence factor of falling film evaporation heat transfer was carried was tested through and the performance of the sieve distributor designed the cold membrane experiment. The result shows that sieve plate distributor can make the material form membrane better on the wall in the tubes, and it has good performance. The impact of spraying density, heat flux, temperature differences in transfer, and the solid content of suspension within the limits on the evaporation heat transfer coefficient was identified. The correlative formula of the evaporation heat transfer coefficient was obtained, with its error between the calculated value and the experimental value within±10%.