Assessing the Impact of Operating Conditions on the Energy and Exergy Efficiency for Multi-Effect Vacuum Membrane Distillation Systems
A comprehensive study was conducted to elucidate the effect of operating conditions on the performance of a multi-effect vacuum membrane distillation pilot plant. A theoretical assessment of the energy and exergy efficiency of the process was achieved using a mathematical model based on heat and mas...
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MDPI AG
2021-05-01
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| Online Access: | https://www.mdpi.com/2073-4441/13/11/1500 |
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| author | A. Najib J. Orfi H. Alansary E. Ali |
| author_facet | A. Najib J. Orfi H. Alansary E. Ali |
| author_sort | A. Najib |
| collection | DOAJ |
| description | A comprehensive study was conducted to elucidate the effect of operating conditions on the performance of a multi-effect vacuum membrane distillation pilot plant. A theoretical assessment of the energy and exergy efficiency of the process was achieved using a mathematical model based on heat and mass transfer, which was calibrated using experimental data obtained from the pilot plant. The pilot plant was a solar vacuum multi-effect membrane distillation (V-MEMD) module comprising five stages. It was found that a maximal permeate mass flux of 17.2 kg/m<sup>2</sup>·h, a recovery ratio of 47.6%, and a performance ratio of 5.38% may be achieved. The resulting gain output ratio (GOR) under these conditions was 5.05, which is comparable to previously reported values. Furthermore, the present work systematically evaluated not only the specific thermal energy consumption (STEC), but also the specific electrical energy consumption (SEEC), which has been generally neglected in previous studies. We show that STEC and SEEC may reach 166 kWh/m<sup>3</sup> and 4.5 kWh/m<sup>3</sup>, respectively. We also observed that increasing the feed flow rate has a positive impact on the process performance, particularly when the feed temperature is higher than 65 °C. Under ideal operational conditions, the exergetic efficiency reached 21.1%, and the maximum fraction of exergy destruction was localized in the condenser compartment. Variation of the inlet hot and cold temperatures at a constant differential showed an interesting and variable impact on the performance indicators of the V-MEMD unit. The difference with the lowest inlet temperatures exhibited the most negative impact on the system performance. |
| first_indexed | 2024-03-10T10:58:19Z |
| format | Article |
| id | doaj.art-2d754bbe63b640b28f02adfb04cac080 |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-10T10:58:19Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-2d754bbe63b640b28f02adfb04cac0802023-11-21T21:41:25ZengMDPI AGWater2073-44412021-05-011311150010.3390/w13111500Assessing the Impact of Operating Conditions on the Energy and Exergy Efficiency for Multi-Effect Vacuum Membrane Distillation SystemsA. Najib0J. Orfi1H. Alansary2E. Ali3Mechanical Engineering Department, King Saud University, Riyadh 11451, Saudi ArabiaMechanical Engineering Department, King Saud University, Riyadh 11451, Saudi ArabiaMechanical Engineering Department, King Saud University, Riyadh 11451, Saudi ArabiaChemical Engineering Department, King Saud University, Riyadh 11451, Saudi ArabiaA comprehensive study was conducted to elucidate the effect of operating conditions on the performance of a multi-effect vacuum membrane distillation pilot plant. A theoretical assessment of the energy and exergy efficiency of the process was achieved using a mathematical model based on heat and mass transfer, which was calibrated using experimental data obtained from the pilot plant. The pilot plant was a solar vacuum multi-effect membrane distillation (V-MEMD) module comprising five stages. It was found that a maximal permeate mass flux of 17.2 kg/m<sup>2</sup>·h, a recovery ratio of 47.6%, and a performance ratio of 5.38% may be achieved. The resulting gain output ratio (GOR) under these conditions was 5.05, which is comparable to previously reported values. Furthermore, the present work systematically evaluated not only the specific thermal energy consumption (STEC), but also the specific electrical energy consumption (SEEC), which has been generally neglected in previous studies. We show that STEC and SEEC may reach 166 kWh/m<sup>3</sup> and 4.5 kWh/m<sup>3</sup>, respectively. We also observed that increasing the feed flow rate has a positive impact on the process performance, particularly when the feed temperature is higher than 65 °C. Under ideal operational conditions, the exergetic efficiency reached 21.1%, and the maximum fraction of exergy destruction was localized in the condenser compartment. Variation of the inlet hot and cold temperatures at a constant differential showed an interesting and variable impact on the performance indicators of the V-MEMD unit. The difference with the lowest inlet temperatures exhibited the most negative impact on the system performance.https://www.mdpi.com/2073-4441/13/11/1500multi-effect membrane distillationperformance indicatorsspecific electrical energy consumptionspecific thermal energy consumptionexergetic efficiencyexergy destruction |
| spellingShingle | A. Najib J. Orfi H. Alansary E. Ali Assessing the Impact of Operating Conditions on the Energy and Exergy Efficiency for Multi-Effect Vacuum Membrane Distillation Systems Water multi-effect membrane distillation performance indicators specific electrical energy consumption specific thermal energy consumption exergetic efficiency exergy destruction |
| title | Assessing the Impact of Operating Conditions on the Energy and Exergy Efficiency for Multi-Effect Vacuum Membrane Distillation Systems |
| title_full | Assessing the Impact of Operating Conditions on the Energy and Exergy Efficiency for Multi-Effect Vacuum Membrane Distillation Systems |
| title_fullStr | Assessing the Impact of Operating Conditions on the Energy and Exergy Efficiency for Multi-Effect Vacuum Membrane Distillation Systems |
| title_full_unstemmed | Assessing the Impact of Operating Conditions on the Energy and Exergy Efficiency for Multi-Effect Vacuum Membrane Distillation Systems |
| title_short | Assessing the Impact of Operating Conditions on the Energy and Exergy Efficiency for Multi-Effect Vacuum Membrane Distillation Systems |
| title_sort | assessing the impact of operating conditions on the energy and exergy efficiency for multi effect vacuum membrane distillation systems |
| topic | multi-effect membrane distillation performance indicators specific electrical energy consumption specific thermal energy consumption exergetic efficiency exergy destruction |
| url | https://www.mdpi.com/2073-4441/13/11/1500 |
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