用于低温多效海水淡化装置的TVC泵设计与试验研究

Design and Test of Thermal Vapor Compressor Pump for Low-Temperature Multi-Effect Seawater Desalination

近些年来,各国新建的日产淡水万吨级以上的非膜法海水淡化装置,大多采取带有TVC泵的低温多效蒸发模式。TVC泵在真空行业又称作水蒸汽喷射泵,本文结合日产淡水万吨级的国产化大型低温多效海水淡化装置的工程案例与实践,介绍了TVC泵的工作原理,对TVC泵的参数设计进行了探讨。为了满足该TVC泵具有调节工作蒸汽流量的功能的要求,本工程案例采用具有自有知识产权的可调式TVC泵的设计方案,并在大型实验平台对TVC泵进行实物模拟试验,对试验数据进行了初步研究,为今后设计适用于大型低温多效蒸发海水淡化工程的TVC泵,提供了可借鉴的、宝贵的设计案例与工程实践。

A novel type of thermal vapor compressor（ TVC） pump with adjustable steam flow-rate,known as steam ejector pump and dedicated to the low-temperature multi-effect distillation（ LT-MED） seawater desalination equipment with 10-kiloton daily capacity,was designed and fabricated on the basis of simulation with self-developed software Computational Fluid Dynamics（ CFD）; theoretically analyzed and experimentally tested in the home-built,large test-platform. The influence of the geometries and arrangement of the adjustable mandrel and nozzle in TVC pump on the steam＇s flow-rate,pressure and temperature was simulated with CFD software and investigated with the test-platform for design optimization. The results show that the axial displacement of the mandrel significantly affects the steam flow-rate across the nozzle-throat because the cross-sectional area of the nozzle-throat strongly depends on the mandrel-nozzle alignment. The adjustable mandrel / nozzle separation results in 40% - 110% variations of desalinationefficiency with minor impact on the other desalination conditions,because the adjustment of mandrel / nozzle separation weakly influences the flow-rate,temperature and pressure of the motive steam.