TY - JOUR
T1 - Analysis of forward osmosis desalination via two-dimensional FEM model
AU - Sagiv, Abraham
AU - Zhu, Aihua
AU - Christofides, Panagiotis D.
AU - Cohen, Yoram
AU - Semiat, Raphael
N1 - Funding Information:
This research was supported by Grant no. 2014337 from the United States–Israel Binational Science Foundation ( BSF ). P. Christofides, Y. Cohen and A. Zhu also acknowledge support from the California Department of Water Resources and the National Science Foundation Grant No. 0963183. Also acknowledged is assistance of Dr. Anditya Rahardianto with determination of solution physicochemical and transport properties.
PY - 2014/8/15
Y1 - 2014/8/15
N2 - Forward osmosis (FO) desalination was investigated via 2-D numerical model of the fully coupled hydrodynamics and mass transfer equations. The model was formulated for a detailed composite channel structure (feed and draw channels, membrane skin layer and porous support) being capable of describing co-current or counter current cross operation where the membrane skin faces the salt feed solution (SFF) or where the membrane skin faces the draw solution (SFD). Simulations based on existing experimental FO data confirmed that FO operation in a counter-current/SFD mode provides slight improvement with respect to water flux, and reduced cross migration of feed and draw solutes relative to the co-current mode of operation. Analysis of existing FO data also revealed the dependence of the intrinsic membrane water permeability and solute transport coefficients on draw solute concentration. Simulation results indicated significant cross membrane migration of feed and draw solutes for long (~1. m) relative to short (~10. cm) FO channels. Moreover, up to an order of magnitude decline of draw solute concentration difference (along the membrane) can be encountered at the draw channel exit region. Simulation results suggest that accurate assessment of FO performance in long channels is critical for full-scale plant design in order to minimize salt leakage, optimize recovery, and setting accurate inlet/outlet conditions to enable simulations of membrane elements in series.
AB - Forward osmosis (FO) desalination was investigated via 2-D numerical model of the fully coupled hydrodynamics and mass transfer equations. The model was formulated for a detailed composite channel structure (feed and draw channels, membrane skin layer and porous support) being capable of describing co-current or counter current cross operation where the membrane skin faces the salt feed solution (SFF) or where the membrane skin faces the draw solution (SFD). Simulations based on existing experimental FO data confirmed that FO operation in a counter-current/SFD mode provides slight improvement with respect to water flux, and reduced cross migration of feed and draw solutes relative to the co-current mode of operation. Analysis of existing FO data also revealed the dependence of the intrinsic membrane water permeability and solute transport coefficients on draw solute concentration. Simulation results indicated significant cross membrane migration of feed and draw solutes for long (~1. m) relative to short (~10. cm) FO channels. Moreover, up to an order of magnitude decline of draw solute concentration difference (along the membrane) can be encountered at the draw channel exit region. Simulation results suggest that accurate assessment of FO performance in long channels is critical for full-scale plant design in order to minimize salt leakage, optimize recovery, and setting accurate inlet/outlet conditions to enable simulations of membrane elements in series.
KW - Concentration polarization
KW - Desalination
KW - FEM modeling
KW - Forward osmosis
KW - Mass transfer
UR - http://www.scopus.com/inward/record.url?scp=84899669044&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2014.04.001
DO - 10.1016/j.memsci.2014.04.001
M3 - 文章
AN - SCOPUS:84899669044
VL - 464
SP - 161
EP - 172
JO - Journal of Membrane Science
JF - Journal of Membrane Science
SN - 0376-7388
ER -