Prediction of spatial-temporal evolution of membrane scaling in spiral wound desalination modules by an advanced simulator

Karabelas, A.J.; Mitrouli, S.T.; Koutsou, C.P.; Kostoglou, Margaritis

doi:10.1016/j.desal.2019.01.027

Cited by 10 publications

(10 citation statements)

References 57 publications

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Section: Results and Discussionmentioning

confidence: 99%

“…39 The change in chemical requirement is difficult to evaluate due to the outsourcing from chemical producing companies that treat this as a case-by-case scenario without a clear and systematic protocol reported. 18 Figure 9 shows the great error that comes from associating the loss in permeation at the point of thermodynamic equilibrium to the presence of fouling. Supersaturated conditions are expected much earlier when considering local SPI rather than permeation loss to assess fouling.…”

Section: Resultsmentioning

confidence: 99%

“…This creates a more accurate depiction of behavior in specific areas of the membrane sheet. 18 , 19 More recent work by Song et al described a 2-D model assuming a shear flow pattern with a nonuniform velocity profile in the y -direction (along the height). The concentration polarization profile was found to be affected by the choice of the flow pattern depending on the channel height.…”

Section: Introductionmentioning

confidence: 99%

“…Their model suggests a change in flow and concentration behavior along the width and the length as the section simulated of the membrane approaches the permeate tube in a spiral wound module. This creates a more accurate depiction of behavior in specific areas of the membrane sheet. , More recent work by Song et al described a 2-D model assuming a shear flow pattern with a nonuniform velocity profile in the y -direction (along the height). The concentration polarization profile was found to be affected by the choice of the flow pattern depending on the channel height .…”

Section: Introductionmentioning

confidence: 99%

“…Karabelas et al accounted for activities as well, assessing fouling tendency of calcium sulfate through an external program “PHREEQC v.3”. Additionally, they correlate solution supersaturation to an experimentally measured scale-mass density component that allows it to simulate the scale deposition rate. , PHREEQC and Minteq are among publicly available water chemistry programs that provide a variety of parameters including activity coefficients . PHREEQC has a coupling feature that allows developers to easily integrate it into their models.…”

Section: Introductionmentioning

confidence: 99%

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Robust Spatial Modeling of Thermodynamic Parameters in a Full-Scale Reverse Osmosis Membrane Channel

et al. 2021

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Full-scale reverse osmosis (RO) units usually consist of a set of pressure vessels holding up to six (1 m long) membrane modules in series. Since process parameters and water composition change substantially along the filtration channel in full-scale RO units, relevant thermodynamic parameters such as the ion activities and the osmotic coefficient change as well. Understanding these changes will lead to more accurate fouling prediction and to improvement in process and equipment designs. In this article, a rigorous thermodynamic model for RO concentrates in a full-scale module is developed and presented, which is capable of accounting for such changes. The change in concentrate composition due to permeation of water and ions is predicted locally in the membrane filtration channel. The local ionic composition is used to calculate the local activity coefficient and osmotic coefficient along the membrane channel through the Pitzer model for each modeled anion and cation. The approach developed was validated against related literature data, showing that Pitzer coefficient predictions were satisfactory. The spatial variation model was verified experimentally. It was found under the modeled conditions of high recovery that individual solute activity coefficients could be diminished up to 65%, in our case for sulfate, from their initial value from the membrane inlet to the outlet, and the water osmotic coefficient increased 3% as concentrate salinity increased from the membrane inlet to the outlet. Modeled at moderate recovery, the sulfate still achieved a statistically significant drop of 34% and an opposing trend of a decrease of 0.5% for the osmotic coefficient. These variations in internal water chemistry along the channel can significantly impact predicted recovery, fouling propensity, and permeate quality. Fouling prediction with our approach was also assessed through a theoretical fouling index to demonstrate the significance of ion activity over concentration-based calculations. Additionally, data from a pilot plant RO filtration channel was used to carry out a sensitivity analysis to show the capability of the developed model.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%