Simulation Study on Direct Contact Membrane Distillation Modules for High-Concentration NaCl Solution
Membrane distillation technology, as a new membrane-based water treatment technology that combines the membrane technology and evaporation process, has the advantages of using low-grade heat, working at atmospheric pressure with simple configuration, etc. In this study, heat and mass transfer were c...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-08-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/10/8/179 |
| _version_ | 1827711643568570368 |
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| author | Weiming Ni Yongli Li Juezhen Zhao Gaoyuan Zhang Xiaoze Du Yingchao Dong |
| author_facet | Weiming Ni Yongli Li Juezhen Zhao Gaoyuan Zhang Xiaoze Du Yingchao Dong |
| author_sort | Weiming Ni |
| collection | DOAJ |
| description | Membrane distillation technology, as a new membrane-based water treatment technology that combines the membrane technology and evaporation process, has the advantages of using low-grade heat, working at atmospheric pressure with simple configuration, etc. In this study, heat and mass transfer were coupled at the membrane surfaces through the user-defined function program. The effects of feed temperature, feed velocity and permeate velocity on temperature polarization were mainly investigated for a high-concentration NaCl solution. The temperature polarization was increased with the increase of feed temperature and the decrease of feed and permeate velocity. The effects of temperature, inlet velocity and solution concentration on the evaporation efficiency of the membrane module for co- and counter-current operations were investigated in detail. The counter-current operation performed better than co-current operation in most cases, except for the condition where the NaCl concentration was relatively low or the module length was long enough. In addition, the optimal membrane thickness for both PVDF and PTFE was studied. The optimal membrane thickness was found in the range of 10 to 20 μm, which corresponded to the highest permeate flux for the selected materials, pore size distribution, and operation conditions. Membrane material with lower thermal conductivity and larger porosity was prone to get higher permeate flux and had larger optimal membrane thickness. Increasing feed velocity or feed temperature could decrease the optimal membrane thickness. |
| first_indexed | 2024-03-10T17:57:27Z |
| format | Article |
| id | doaj.art-e685de61b2c04c2f9e161afb61ed91aa |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-10T17:57:27Z |
| publishDate | 2020-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj.art-e685de61b2c04c2f9e161afb61ed91aa2023-11-20T09:09:10ZengMDPI AGMembranes2077-03752020-08-0110817910.3390/membranes10080179Simulation Study on Direct Contact Membrane Distillation Modules for High-Concentration NaCl SolutionWeiming Ni0Yongli Li1Juezhen Zhao2Gaoyuan Zhang3Xiaoze Du4Yingchao Dong5Key Laboratory of Power Station Energy Transfer Conversion and System (North China Electric Power University), Ministry of Education, Beijing 102206, ChinaKey Laboratory of Power Station Energy Transfer Conversion and System (North China Electric Power University), Ministry of Education, Beijing 102206, ChinaKey Laboratory of Power Station Energy Transfer Conversion and System (North China Electric Power University), Ministry of Education, Beijing 102206, ChinaKey Laboratory of Power Station Energy Transfer Conversion and System (North China Electric Power University), Ministry of Education, Beijing 102206, ChinaSchool of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, ChinaSchool of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, ChinaMembrane distillation technology, as a new membrane-based water treatment technology that combines the membrane technology and evaporation process, has the advantages of using low-grade heat, working at atmospheric pressure with simple configuration, etc. In this study, heat and mass transfer were coupled at the membrane surfaces through the user-defined function program. The effects of feed temperature, feed velocity and permeate velocity on temperature polarization were mainly investigated for a high-concentration NaCl solution. The temperature polarization was increased with the increase of feed temperature and the decrease of feed and permeate velocity. The effects of temperature, inlet velocity and solution concentration on the evaporation efficiency of the membrane module for co- and counter-current operations were investigated in detail. The counter-current operation performed better than co-current operation in most cases, except for the condition where the NaCl concentration was relatively low or the module length was long enough. In addition, the optimal membrane thickness for both PVDF and PTFE was studied. The optimal membrane thickness was found in the range of 10 to 20 μm, which corresponded to the highest permeate flux for the selected materials, pore size distribution, and operation conditions. Membrane material with lower thermal conductivity and larger porosity was prone to get higher permeate flux and had larger optimal membrane thickness. Increasing feed velocity or feed temperature could decrease the optimal membrane thickness.https://www.mdpi.com/2077-0375/10/8/179direct contact membrane distillationevaporation efficiencyoptimal membrane thicknesshigh-salt wastewater |
| spellingShingle | Weiming Ni Yongli Li Juezhen Zhao Gaoyuan Zhang Xiaoze Du Yingchao Dong Simulation Study on Direct Contact Membrane Distillation Modules for High-Concentration NaCl Solution Membranes direct contact membrane distillation evaporation efficiency optimal membrane thickness high-salt wastewater |
| title | Simulation Study on Direct Contact Membrane Distillation Modules for High-Concentration NaCl Solution |
| title_full | Simulation Study on Direct Contact Membrane Distillation Modules for High-Concentration NaCl Solution |
| title_fullStr | Simulation Study on Direct Contact Membrane Distillation Modules for High-Concentration NaCl Solution |
| title_full_unstemmed | Simulation Study on Direct Contact Membrane Distillation Modules for High-Concentration NaCl Solution |
| title_short | Simulation Study on Direct Contact Membrane Distillation Modules for High-Concentration NaCl Solution |
| title_sort | simulation study on direct contact membrane distillation modules for high concentration nacl solution |
| topic | direct contact membrane distillation evaporation efficiency optimal membrane thickness high-salt wastewater |
| url | https://www.mdpi.com/2077-0375/10/8/179 |
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