精馏规整填料表面水与液氮降膜流动特性对比研究  

Comparative study on flow characteristics of water and liquid nitrogen falling film on surface of structured packing

作　　者：扈诗语 植晓琴[1,2,3] 顾陈杰 詹高铭 滕艺璇 邱利民 Hu Shiyu;Zhi Xiaoqin;Gu Chenjie;Zhan Gaoming;Teng Yixuan;Qiu Limin(Institute of Refrigeration and Cryogenics,Zhejiang University,Hangzhou 310027,China;Key Laboratory of Clean Energy and Carbon Neutrality of Zhejiang Province,Hangzhou 310027,China;Jiaxing Research Institute of Zhejiang University,Jiaxing 314000,China)

机构地区：[1]浙江大学制冷与低温研究所,杭州310027 [2]浙江省清洁能源与碳中和重点实验室,杭州310027 [3]浙江大学嘉兴研究院,嘉兴314000

出　　处：《低温工程》2022年第5期41-47,共7页Cryogenics

基　　金：国家自然科学基金(52176024)。

摘　　要：规整填料间两相流动状态及界面特性直接影响精馏塔甚至整个空分流程的性能,低温精馏的发展长期依赖常温物系测试,针对低温流体气液界面逆流作用特性尚未有公开研究。借助CFD方法,建立了基于规整填料Mellapak 250Y的局部逆流可代表性单元模型(REU),通过分析流动形态、局部润湿率和持液率,研究以水和液氮在规整填料上的流动特性差异。结果发现,当气相静止时,液氮整体润湿率大于90%,远大于水,在低流量成完全膜状流态。相比水,液氮由于具有低表面张力和低液气密度比,界面更易受到逆流气体影响,出现剧烈波动和液膜撕裂,润湿性显著下降,导致低温物系的泛点相比水-空气显著提前。The characteristics between structured packings directly affect the performance of the distillation column.The development of cryogenic distillation has relied on the test of normal temperature material systems for a long time,and there has been no public research on the countercurrent characteristics of the gas-liquid interface of cryogenic fluids.In this paper,with the help of CFD method,a representative element unit(REU)of local counterflow based on structured packing Mellapak 250Y is established.By analyzing the flow morphology,local wettability and liquid holdup,the difference in flow characteristics of water and liquid nitrogen on structured packing was investigated.It was found that when the gas phase was stationary,the overall wetting rate of liquid nitrogen was greater than 90%,much larger than that of water,and it became a complete film flow state at low flow rates.Due to the surface tension and low liquid-to-gas density ratio,the interface is easily affected by countercurrent gas,resulting in violent fluctuations and tearing of the liquid film,and the wettability decreases significantly,resulting in a significantly earlier flooding of cryogenic system than water-air.

关 键 词：规整填料 两相逆流 水 液氮 流动特性 

分 类 号：TB61[一般工业技术—制冷工程] TB663