膜蒸馏系统的热质扩散耦合分析  

Coupled analysis of thermal and mass diffusion in membrane distillation system

作　　者：吉彦龙 卢小平[1] 魏彦艳 JI Yanlong;LU Xiaoping;WEI Yanyan(Institute of Petrochemical Technology Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学石油化工学院,兰州730050

出　　处：《膜科学与技术》2021年第2期51-55,62,共6页Membrane Science and Technology

基　　金：国家自然科学基金项目(51566010)。

摘　　要：从相变耦合、逆流换热耦合以及蒸汽分子在膜孔中热质扩散耦合的角度出发,分别分析了热物料侧相变热质传递过程、膜蒸馏系统逆流换热过程以及蒸汽分子在膜孔中的热质扩散过程,并建立了三者与膜通量之间的关系式.得出自发的蒸汽分子迁移过程驱动了非自发的传热过程,当传质过程强化时,蒸汽分子传递速率增加,导致膜通量增加;膜蒸馏系统换热的强化有助于削弱温度极化,伴随着膜两侧表面温度梯度的增加,膜通量增加;关系式同时说明了减小膜的厚度,有利于膜通量增加.Membrane flux is an important index to measure membrane distillation technology.Low membrane flux seriously limits the industrial development of membrane distillation technology.From the perspective of phase change coupling and countercurrent heat transfer coupling and the thermal diffusion coupling of steam molecules in membrane pores,the phase change heat and mass transfer process at hot material side,countercurrent heat transfer process in membrane distillation system and vapor molecules in membrane are analyzed respectively,and the relationship between the heat and mass transfer process and the membrane flux is established.It is concluded that the spontaneous vapor molecular transfer process drives the non-spontaneous heat transfer process.When the mass transfer process is strengthened,the vapor molecular transfer rate increases,resulting in the increase of membrane flux,the enhancement of heat transfer in membrane distillation system helps to weaken the temperature polarization,accompanied by the increase of temperature gradient on both sides of the membrane surface,at the same time,the relationship also shows that the decrease of membrane thickness is beneficial to the increase of membrane flux.

关 键 词：相变 热质扩散耦合 逆流换热强化 膜通量 

分 类 号：TQ028[化学工程] TK2[动力工程及工程热物理—动力机械及工程]