Multistage Flash Desalination with an Integrated Solar System
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• The variations in sun altitude angle, angle of
incidence and solar beam during the day
• Useful heat gain
• The MSF temperature, solar field outlet temperature
and tank temperature
• Many countries around the world continue to suffer
from water shortages.
• The current conventional desalination technologies
are expensive and energy-consuming.
• The growth in global desalinated installation has
been increasing exponentially.
Multistage Flash Desalination with an Integrated Solar System Mishal Alsehli
Advisor: Jun-Ki Choi, Ph.D.
MOTIVATION
• Desalination processes are classified as thermal or
membrane technology.
•MSF and RO are the most widely used technologies.
MSF: Multistage-Flash
RO: Reverse Osmosis
INTRODUCTION
FRAMEWORK
• High energy consumption.
Energy requirements
Thermal energy (kJ/kg): 250–300
Electrical energy (kWh/m3): 3.5–5
• Environmental harm.
Emits GHG (kg CO2/m3H2O): 15-25
MSF TECHNOLOGY
• The structure of the system is divided into three
blocks:
1. MSF.
2. Solar Collector.
3. Thermal Storage Tank.
• Two main advantages :
1. The expected fuel saving is about 80%.
2. Minimizes land use of solar field.
MSF WITH INTEGRATED SOLAR SYSTEM RESULTS
Desalination
Thermal
MSF
MED
VC
Membrane
RO
ED
RO: 44%
MSF: 40%
MED: 2%
VC: 3%
ED: 5%
Other: 2%
MODEL
CONCLUSION
• The storage tank provides the plant with thermal
energy for entire day at full capacity.
• The total area of solar field is small compared to a
another design’s solar field with the same heat gain.
• The fuel saving is around eighty percent of total
energy of conventional MSF.
REFERENCES
1. Hamed, O.A., et al. Prospects of improving energy
consumption of the multi-stage flash distillation process. in
Proceedings of the Fourth Annual Workshop on Water
Conservation in Dhahran the Kingdom of Saudi Arabia. 2001.
2. van der Vegt, H., et al., Patent Landscape Report on
Desalination Technologies and Use of Alternative Energies for
Desalination. 2011: World Intellectual Property Organization.
3. Gude, V.G., N. Nirmalakhandan, and S. Deng, Renewable
and sustainable approaches for desalination. Renewable and
Sustainable Energy Reviews, 2010. 14(9): p. 2641-2654.
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Acknowledgement: This work is supported by the University of Dayton for the research council seed grant (Grant No. IGRQ14). Part of this research was supported by the KSA government’s academic research fellowship through Taif University (228-24/06/1433).
• Each part is modeled as a single unit with both
mass and energy balance.
1. MSF
Brine flow rate in stage i: 𝐵 = 𝑀𝑓 − 𝐷
Distillate flow rate in stage i: 𝐷𝑖 = 𝑦𝑀𝑓(1 − 𝑦)(𝑖−1)
2. Solar Collector
Useful output of the collector:
𝑄𝑢 = 𝐹𝑅𝐴𝑎 𝑆 −𝐴𝑟𝑜𝐴𝑎
𝑈𝐿
𝑇𝑓𝑖 − 𝑇𝑎
3. Thermal Storage Tank:
The rate change of internal energy:
𝐶𝑃𝑓 dM
𝑑𝑡= 𝑚𝑖 𝐶𝑃𝑇ℎ − 𝑚𝑜 𝐶𝑃𝑇ℎ − 𝑈𝐴 𝑡(𝑇 − 𝑇𝑒𝑛𝑣)