TY - JOUR
T1 - Recent development in thermally activated desalination methods: achieving an energy efficiency less than 2.5 kWhelec/m3
AU - Shahzad, Muhammad Wakil
AU - Thu, Kyaw
AU - Ng, Kim Choon
AU - WonGee, Chun
N1 - KAUST Repository Item: Exported on 2020-10-01
PY - 2015/5/19
Y1 - 2015/5/19
N2 - Water-Energy-Environment nexus is a crucial consideration when designing seawater desalination processes, particularly for the water-stressed countries where the annual water availability is less than 250 m3 per capita. Despite the thermodynamics limit for seawater desalination at normal conditions is about 0.78 to 1.09 kWhelec/m3, the specific energy consumption of desalination of real plants is found to operate at several folds higher. Today’s technological advancement in membranes, namely the reverse osmosis processes, has set an energy consumption of around 3.5–5 kWhelec/m3, while the conventional perception of thermally activated processes such as MSF and MED tends to be higher. Although the higher energetic specific consumption of MED or MSF processes appeared to be higher at 60–100 kWhthermal/m3, their true electricity equivalent has been converted, hitherto, using the energetic analyses where the work potential of working steam of the processes cannot be captured adequately. Thermally activated processes, such as MED and MSF, form the bottoming cycle of a cogeneration plant where both electricity and desalination processes operate in tandem in a cascaded manner. Only the bled-steam at lower exergy is extracted for the desalination processes. In this presentation, we demonstrate that in a cogen plant with 30% bled-steam for MED processes, the exergy destruction ratio is found to be less than 7% of the total available exergy that emanated from the boilers. By the exergetic approach, the equivalent electricity consumption of an average 75 kWhthermal/m3 would result in an electrical equivalent of less than 2.5 kWhelec/m3. Also in this presentation, the authors will elaborate the latest developments in the use of hybridization concept where the MED and the AD cycles are thermodynamically integrated and enhancing the overall efficiency of desalination. © 2015 Balaban Desalination Publications. All rights reserved.
AB - Water-Energy-Environment nexus is a crucial consideration when designing seawater desalination processes, particularly for the water-stressed countries where the annual water availability is less than 250 m3 per capita. Despite the thermodynamics limit for seawater desalination at normal conditions is about 0.78 to 1.09 kWhelec/m3, the specific energy consumption of desalination of real plants is found to operate at several folds higher. Today’s technological advancement in membranes, namely the reverse osmosis processes, has set an energy consumption of around 3.5–5 kWhelec/m3, while the conventional perception of thermally activated processes such as MSF and MED tends to be higher. Although the higher energetic specific consumption of MED or MSF processes appeared to be higher at 60–100 kWhthermal/m3, their true electricity equivalent has been converted, hitherto, using the energetic analyses where the work potential of working steam of the processes cannot be captured adequately. Thermally activated processes, such as MED and MSF, form the bottoming cycle of a cogeneration plant where both electricity and desalination processes operate in tandem in a cascaded manner. Only the bled-steam at lower exergy is extracted for the desalination processes. In this presentation, we demonstrate that in a cogen plant with 30% bled-steam for MED processes, the exergy destruction ratio is found to be less than 7% of the total available exergy that emanated from the boilers. By the exergetic approach, the equivalent electricity consumption of an average 75 kWhthermal/m3 would result in an electrical equivalent of less than 2.5 kWhelec/m3. Also in this presentation, the authors will elaborate the latest developments in the use of hybridization concept where the MED and the AD cycles are thermodynamically integrated and enhancing the overall efficiency of desalination. © 2015 Balaban Desalination Publications. All rights reserved.
UR - http://hdl.handle.net/10754/566156
UR - http://www.tandfonline.com/doi/full/10.1080/19443994.2015.1035499
UR - http://www.scopus.com/inward/record.url?scp=84929593901&partnerID=8YFLogxK
U2 - 10.1080/19443994.2015.1035499
DO - 10.1080/19443994.2015.1035499
M3 - Article
SN - 1944-3994
VL - 57
SP - 7396
EP - 7405
JO - Desalination and Water Treatment
JF - Desalination and Water Treatment
IS - 16
ER -