Modeling the effects of fouling on full-scale reverse osmosis processes

Hoek, Eric M.V.; Allred, Jeff; Knoell, Tom; Jeong, Byeong‐Heon

doi:10.1016/j.memsci.2008.01.025

Cited by 177 publications

(90 citation statements)

References 41 publications

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“…Although flux decline comparisons often keep initial flux constant because of the dependence of fouling rate on flux [9], differences in membrane properties and solution composition can lead to differences in flux decline between experiments even if the foulant layers are identical in size and structure. Flux decline effectively measures the response of the system to fouling; however, it can only hint at the quantity of accumulated foulant.…”

Section: Limitations Of Flux Declinementioning

confidence: 99%

Quantifying osmotic membrane fouling to enable comparisons across diverse processes

Tow

Lienhard

2016

Journal of Membrane Science

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In this study, a method of in situ membrane fouling quantification is developed that enables comparisons of foulant accumulation between desalination processes with different membranes, driving forces, and feed solutions. Unlike the conventional metric of flux decline, which measures the response of a process to fouling, the proposed method quantifies the foulant accumulation. Foulant accumulation is parameterized by two variables, cake structural parameter and hydraulic diameter, that are calculated from flux measurements using a model for salt and water transport through fouled reverse osmosis (RO) and forward osmosis (FO) membranes, including dispersive mass transfer in the FO membrane support layer. Model results show that pressure declines through the foulant layer and can, in FO, reach negative absolute values at the membrane. Experimental alginate gel fouling rates are measured within a range of feed ionic compositions where cake hydraulic resistance is negligible. Using both flux decline and cake structural parameter as metrics, the effect of feed salinity on RO fouling is tested and RO is compared to FO. When RO is fouled with alginate, feed salinity and membrane permeability affect flux decline but not foulant accumulation rate. Between FO and RO, the initial rates of foulant accumulation are similar; however, FO exhibits slower flux decline, which causes greater foulant accumulation over time. The new methodology enables meaningful quantification and comparison of fouling rates with the aim of improving fundamental understanding of fouling processes.

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Section: Limitations Of Flux Declinementioning

confidence: 99%

Quantifying osmotic membrane fouling to enable comparisons across diverse processes

Tow

Lienhard

2016

Journal of Membrane Science

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“…Some researchers use the classical film theory, which requires the knowledge of a mass-transfer coefficient, using a model that considers the mass transfer equations in the proximity of the membrane surface. Some of them assume a uniform solute concentration and permeate flux over the membrane surface [10] but others consider these variables as channel length dependent [6,11,12].…”

Section: Introductionmentioning

confidence: 99%

Visualization and modeling of the polarization layer in crossflow reverse osmosis in a slit-type channel

Salcedo‐Díaz

García-Algado

Garcia‐Rodriguez

et al. 2014

Journal of Membrane Science

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The evolution of the concentration polarization layer during crossflow reverse osmosis in a slit channel has been studied. Digital Holographic Interferometry allows visualizing the polarization layer as an interference fringe pattern. An especial module with four windows has been designed to see the development of the polarization layer along the membrane channel. Several experiments with a constant transmembrane pressure of 6 bar, three different feed concentrations (3, 6 and 9 kg/m 3 ) and three different Re (13, 38 and 111) had been carried out. The process has been modelled simulating the experimental conditions. The computed results were found to be consistent with the experimental ones. All the experiments show a continuous increase of the polarization layer along the channel, regardless of the crossflow velocity, except near the outlet of the cell due to an edge effect. This increase in the polarization layer is greater at lower Re, although it does not influence very much the permeate flux. In contrast, what substantially affects the permeate flux, much more than Re number, is the feed concentration due to its osmotic pressure.

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“…Para reverter esta condição, são estipulados parâmetros, que permitem avaliar a influência ocasionada por variações de comportamento do fouling ao longo da trajetória e a análise detalhada da resistência à permeação. Hoek (2008), para a modelagem dos efeitos do fouling em processos de osmose inversa, verificou que o modelo proposto prediz razoavelmente os dados obtidos experimentalmente, mas inicialmente subestima a queda de pressão hidráulica. Utilizando a correlação empírica de Schock e Miquel (1987), que considera a utilização de parâmetros, foi possível considerar esta queda de pressão e o modelo pode então, descrever o fenômeno de fouling.…”

Section: Resultsunclassified

Modelagem De Um Processo De Concentração, Purificação E Fracionamento Dos Componentes Do Soro Do Leite Através De Tecnologia De Separação Por Membranas

Jesus¹,

Toss²,

Baldasso³

et al. 2015

Anais Do XX Congresso Brasileiro De Engenharia Química

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RESUMO -Os processos de separação por membranas têm demonstrado grande importância nos últimos anos em uma gama de aplicações. Neste mesmo âmbito e considerando o alto volume de soro de leite gerado na produção de queijo, além de seu elevado potencial poluidor, a busca por técnicas adequadas de fracionamento, modificação e preservação das proteínas do soro tem se intensificado. Foi verificado que a utilização de membranas de eletrodiálise e osmose inversa, no tratamento de efluentes gerados na produção de queijos se apresentam como métodos atraentes e econômicos. O objetivo do trabalho é comparar modelos matemáticos dos processos de concentração e purificação do soro de leite com dados experimentais. Alvitrou-se um modelo matemático para o processo de purificação da lactose por eletrodiálise e para o processo de recuperação da água por osmose inversa. Os modelos mostraramse adequados ao início do processo e no decorrer houve discrepâncias, por não considerarem o fenômeno de fouling.

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Modeling the effects of fouling on full-scale reverse osmosis processes

Cited by 177 publications

References 41 publications

Quantifying osmotic membrane fouling to enable comparisons across diverse processes

Quantifying osmotic membrane fouling to enable comparisons across diverse processes

Visualization and modeling of the polarization layer in crossflow reverse osmosis in a slit-type channel

Modelagem De Um Processo De Concentração, Purificação E Fracionamento Dos Componentes Do Soro Do Leite Através De Tecnologia De Separação Por Membranas

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