Deep Concentration of Brine by Multiple-Effect Membrane Distillation at High Temperature
JIN Jun-Bao1, QIN Ying-Jie1, 2 , WANG Ben1, WANG Bin1, CUI Dong-Sheng2, LIU Li-Qiang2
(1School of Chemical Engineering and Technology， Tianjin University， Tianjin 300072， China;
2Chembrane Engineering and Technology， Inc.， Tianjin 300308，China)
Abstract：
Membrane distillation is usually operated at temperature <90 ℃. However, when dealing with concentrated salt, permeation flux (J) and thermal efficiency are much lower because of the reduction of vapor pressure, as well as concentration and temperature polarization effects. In this paper， multiple-effect membrane distillation (MEMD) was explored in the range of 85—105 ℃ for deep concentrating feed of NaCl solutions. The effects of cold feedin temperature T1 heated feed temperature T3 feed-in concentration and feedin flow rate on J , performance ratio (PR) and retention rate were investigated. The experimental result indicated that the J and PR were 3.1 L/(m2·h) and 15.2 for 5% NaCl solution when T3 was 100 ℃, the values of both J and PR decreased with the increase of feed concentration, however, their values could still achieve 1.53 L/(m2·h) and 5.8 respectively for 25% NaCl solution when the value of T3 was 105 ℃, while the salt retention rate could reach more than 99.95%. Also, a long-tern operational stability of the MEMD process was tested for 15% NaCl solution for 60 days. The experimental results indicated that MEMD process showed good operation stability.
JIN Jun-Bao, QIN Ying-Jie, WANG Ben, WANG Bin, CUI Dong-Sheng, LIU Li-Qiang.Deep Concentration of Brine by Multiple-Effect Membrane Distillation at High Temperature[J]. Chemcial Industry and Engineering, 2014,31(2): 31-37
2014, Vol. 31 
