Exergy Analysis of Reverse Osmosis for Potable Water and Land Irrigation

Authors: M. Sarai Atab, A. Smallbone, A. P. Roskilly

Abstract:

A thermodynamic study is performed on the Reverse Osmosis (RO) desalination process for brackish water. The detailed RO model of thermodynamics properties with and without an energy recovery device was built in Simulink/MATLAB and validated against reported measurement data. The efficiency of desalination plants can be estimated by both the first and second laws of thermodynamics. While the first law focuses on the quantity of energy, the second law analysis (i.e. exergy analysis) introduces quality. This paper used the Main Outfall Drain in Iraq as a case study to conduct energy and exergy analysis of RO process. The result shows that it is feasible to use energy recovery method for reverse osmosis with salinity less than 15000 ppm as the exergy efficiency increases twice. Moreover, this analysis shows that the highest exergy destruction occurs in the rejected water and lowest occurs in the permeate flow rate accounting 37% for 4.3% respectively.

Keywords: Brackish water, exergy, irrigation, reverse osmosis.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.2643514

References:

[1] Ranjan, K.R. and S.C. Kaushik, Energy, exergy and thermo-economic analysis of solar distillation systems: A review. Renewable and Sustainable Energy Reviews, 2013. 27: p. 709-723.
[2] Kotas, T.J., The exergy method of thermal plant analysis. London ao: Butterworths, 2012.
[3] Cerci, Y., Exergy analysis of a reverse osmosis desalination plant in California. Desalination, 2002. 142(3): p. 257-266.
[4] Eshoul, N.M., et al., Exergy Analysis of a Two-Pass Reverse Osmosis (RO) Desalination Unit with and without an Energy Recovery Turbine (ERT) and Pressure Exchanger (PX). Energies, 2015. 8(7): p. 6910-6925.
[5] El-Emam, R.S. and I. Dincer, Thermodynamic and thermoeconomic analyses of seawater reverse osmosis desalination plant with energy recovery. Energy, 2014. 64: p. 154-163.
[6] Sarai Atab, M., A.J. Smallbone, and A.P. Roskilly, An operational and economic study of a reverse osmosis desalination system for potable water and land irrigation. Desalination, 2016. 397: p. 174-184.
[7] Tsatsaronis, G., Definitions and nomenclature in exergy analysis and exergoeconomics. Energy, 2007. 32(4): p. 249-253.
[8] Bejan, A. and M.J. Moran, Thermal design and optimization. 1996: John Wiley & Sons.
[9] Bejan, A., Advanced engineering thermodynamics. 2006, John Wiley & Sons, Hoboken, NJ
[10] Sharqawy, M.H., S.M. Zubair, and J.H. Lienhard, Second law analysis of reverse osmosis desalination plants: An alternative design using pressure retarded osmosis. Energy, 2011. 36(11): p. 6617-6626.
[11] Aljundi, I.H., Second-law analysis of a reverse osmosis plant in Jordan. Desalination, 2009. 239(1): p. 207-215.
[12] Wijmans, J.G. and R.W. Baker, The solution-diffusion model: a review. Journal of Membrane Science, 1995. 107(1–2): p. 1-21.
[13] Lee, S. and R.M. Lueptow, Membrane rejection of nitrogen compounds. 2001.
[14] Cheryan, M., Ultrafiltration and microfiltration handbook. 1998: CRC press.
[15] R.Rautenbach and R.Albrecht, Membrane Processes. 1981, West Germany: John Wiley and Sons Ltd.
[16] Avlonitis, S.A., M. Pappas, and K. Moutesidis, A unified model for the detailed investigation of membrane modules and RO plants performance. Desalination, 2007. 203(1–3): p. 218-228.
[17] Baker, R.W., Membrane Technology and Applications. 2004, John Wiley & Sons, Ltd., Chichester.
[18] Vince, F., et al., Multi-objective optimization of RO desalination plants. Desalination, 2008. 222(1–3): p. 96-118.
[19] DOW, Design a Reverse Osmosis System: Design Equations and Parameters, Technical Manual 2006.
[20] I. Dincer, M.A.R., Exergy, Energy, Environment and Simulation Development, Exergy Elsever, Oxford, 2007. firs ed.
[21] I. Dincer, M.A.R., Exergy, Thermal Energy Storage Systems and Applications, 2011. Second ed., John Wiley & sons, Oxford.
[22] Sharqawy, H.M., J.H. Lienhard V, and M.S. Zubair, On exergy calculation of seawater with application in desalination systems International Journal of Thermal Sciences, 2011. 50.
[23] Sharqawy, M.H., J.H. Lienhard, and S.M. Zubair, Thermophysical properties of seawater: a review of existing correlations and data. Desalination and Water Treatment, 2010. 16(1-3): p. 354-380.
[24] Vosough, A., et al., Exergy concept and its characteristic. International Journal of Multidisciplinary Sciences and Engineering, 2011. 2(4): p. 47-52.
[25] Al-Weshahi, M.A., A. Anderson, and G. Tian, Exergy efficiency enhancement of MSF desalination by heat recovery from hot distillate water stages. Applied Thermal Engineering, 2013. 53(2): p. 226-233.