A comprehensive review of energy consumption of seawater reverse osmosis desalination plants

Kim, Jungbin,Park, Kiho,Yang, Dae Ryook,Hong, Seungkwan ELSEVIER 2019 APPLIED ENERGY -BARKING THEN OXFORD- Vol.254 No.-

<P><B>Abstract</B></P> <P>High specific energy consumption (SEC) is the main barrier for the expansion of seawater reverse osmosis (SWRO). Therefore, the main objective of current SWRO research is to lower the SEC of SWRO plants. However, SEC of SWRO plants has not been systemically explored or analyzed, despite the need for information to develop appropriate strategies to reduce SEC. Therefore, this study aims to review and analyze SWRO plants for a comprehensive understanding of their SEC. First, trends in SWRO application are investigated using more than 70 datasets on large-scale SWRO. The analysis explains the increasing number of large-size SWRO plants, the SEC reduction by isobaric energy recovery devices (ERDs), and the use of different SWRO configurations to meet the energy and quality requirements. Factors associated with SEC (<I>i.e.</I>, feed conditions, target conditions, and equipment efficiency) are also analyzed. High salinity increases energy demand, whereas the temperature effect on energy consumption is not entirely clear. High-efficiency ERDs and pumps can reduce SEC, but overall SEC cannot be explained by these factors alone. SEC is also affected by target water quality and quantity. Moreover, specific SWRO designs can improve the system to efficiently achieve the established goals. Furthermore, future directions to develop low-energy SWRO plants are discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Critical review of energy consumption of seawater reverse osmosis plants. </LI> <LI> Collection of more than 70 datasets for large-size seawater reverse osmosis plants. </LI> <LI> Investigation of trends in the application of seawater reverse osmosis plants. </LI> <LI> Analysis of factors associated with energy consumption of seawater reverse osmosis. </LI> <LI> Future directions to reduce energy consumption of seawater reverse osmosis plants. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Boron transport in forward osmosis: Measurements, mechanisms, and comparison with reverse osmosis

Kim, C.,Lee, S.,Shon, H.K.,Elimelech, M.,Hong, S. Elsevier Scientific Pub. Co 2012 Journal of membrane science Vol.419 No.-

The physical and chemical factors affecting boron solute flux behavior and membrane transport mechanisms in forward osmosis (FO) have been systematically investigated. Boron solute flux behavior in FO was further compared with that in reverse osmosis (RO) by employing identical plate-and-frame cells and membranes under the same filtration conditions. The influence of draw solution pH, draw solution type, and membrane orientation on boron solute flux was examined for FO, and the effects of water flux, cross-flow velocity, feed water boron concentration, and solution pH on boron solute flux were examined for both FO and RO. Results show that reverse salt diffusion, a unique feature of FO, is a key mechanism governing boron solute flux in FO. Boron solute flux through the FO membrane was inversely proportional to the degree of reverse salt diffusion by draw solution. The higher boron rejection observed in FO compared to RO is also attributed to reverse salt diffusion in FO. It is also shown that membrane orientation in FO plays an important role, affecting boron solute flux due to different degrees of internal concentration polarization. In both FO and RO, boron solute flux increased with increasing water flux. However, the influence of water flux on boron solute flux was less significant in FO than RO. Furthermore, boron solute flux decreased with increasing feed water pH due to the conversion of the neutral boric acid to borate anions. The findings provide new insight into the mechanisms and factors controlling boron solute transport in FO.

하수를 공업용수로 재이용하기 위한 정밀여과 및 역삼투 시스템 적용에 관한 연구

강신경,이해군,김지원 한국막학회 2002 멤브레인 Vol.12 No.3

본 연구는 하수를 공업용수로 재이용하기 위한 분리막 시스템 적용에 관한 연구이다. 정밀여과와 역삼투시스템으로 구성된 bench scale 실험장치를 이용하여 하수처리장 현장에서 실험을 수행한 결과, 정밀여과 시스템은 이온성분은 제거할 수 없었으나 SS를 70% 이상 처리할 수 있어 처리수는 직접냉각수로 재이용이 가능하였다. 그리고 역삼투 시스템은 SS는 물론 이온성분도 95% 이상 제거할 수 있어 처리수는 간접냉각수 및 제품세척수로 사용이 가능하였다. $100 m^3$/일 용량의 pilot Plant를 제작하기 위해서는 정밀여과 모듈은 20개, 역삼투 모듈은 12개가 필요하였다. This research was to demonstrate the Possibility of sewage reuse for industrial purpose with use of membrane system. A bench scale test with microfiltration and reverse osmosis showed that microfiltration in the sewage treatment was not able to remove the soluble salts but 70% suspended solids (SS), suggesting that the treated water could be used as direct cooling water. In addition, the reverse osmosis removed not only soluble salts but also 95% SS, proposing that reverse osmosis-treated water could be used as both indirect cooling water and rinsing water. For a 100 ton/day pilot plant, 20 and 12 elements of microfiltration and reverse osmosis were required, respectively.

Organic fouling and reverse solute selectivity in forward osmosis: Role of working temperature and inorganic draw solutions

Heo, J.,Chu, K.H.,Her, N.,Im, J.,Park, Y.G.,Cho, J.,Sarp, S.,Jang, A.,Jang, M.,Yoon, Y. Elsevier 2016 Desalination Vol.389 No.-

The water flux of several draw solutions (DSs, solutes: KCl, NaCl, CaCl<SUB>2</SUB>, Na<SUB>2</SUB>SO<SUB>4</SUB>) and fouling propensity of two different organic foulants (humic acid and alginate) were systematically investigated using forward osmosis (FO) and unpressurized pressure-retarded osmosis. In addition, reverse solute selectivity was evaluated to characterize the water and salt transport mechanisms at different temperatures and in the presence of four different inorganic DS compounds. The influence of solution viscosity has significant implications in FO applications, because the water molecules easily penetrated and diffused throughout the FO membrane active layer (AL) and supporting layer (SL) with increasing temperatures, which is mainly correlated with the lower water viscosities with increasing temperatures. The results indicated that the water flux on average significantly increased from 9.5 to 13.7 and 24.9 LMH when the operating temperature was increased from 5 to 20 and 45<SUP>o</SUP>C, which corresponded to a 44 and 262% increase in the water flux, compared to the FO mode at 5<SUP>o</SUP>C. However, the water flux and viscosity exhibited generally constant trends with respect to the elevating temperature. In addition, elevating temperature increased the reverse solute flux selectivity (RSFS), not only by decreasing the internal concentration polarization (the AL and SL) and the wettability within the effective porosity of the SL, but also via the improvement of water molecule diffusion kinetics rather than solute diffusion. In addition, the RSFS was inversely related to the solute permeability of the different DSs and followed the order Na<SUB>2</SUB>SO<SUB>4</SUB>>CaCl<SUB>2</SUB>>NaCl>KCl. These results have significant implications for the prediction of water flux behavior and the selection of DSs at different temperatures in osmotically driven FO processes.

역삼투압법으로 제조한 대파 농축액의 휘발성 향기 성분 특성

심재언,이대희,이상미 한국식품조리과학회 2022 한국식품조리과학회지 Vol.38 No.3

Purpose: This study identifies and compares the volatile compounds in Welsh onion juice and Welsh onion concentrates using reverse osmosis. Methods: Volatile compounds in Welsh onion juice and Welsh onion concentrates were analyzed using solvent-assisted flavor evaporation followed by gas chromatography-mass spectrometry. Results: In total, 30 and 31 of volatile compounds were found in Welsh onion juice and Wwelsh onion concentrates by reverse osmosis, respectively. These include alcohols, aldehydes, esters, furans, acids, hydrocarbons, and sulfur-containing compounds. Of these, the sulfur-containing compounds, which are characteristic flavor compounds in raw Welsh onions, were predominant in Welsh onion juice and Welsh onion concentrates. In particular, the contents of some sulfur compounds, such as dimethyl disulfide, (Z)-propenyl methyl disulfide, (E)-Propenyl methyl disulfide, dimethyl trisulfide, (Z)-propenyl propyl disulfide, (E)-propenyl propyl disulfide, methyl propyl trisulfide, dipropyl trisulfide, dimethyl tetrasulfide, and 3,5-diethyl-1,2,4-trithiolane, were higher in Welsh onion concentrates than in Welsh onion juice. Conclusion: These results indicate that sulfur-containing compounds are the major contributors to the unique flavor characteristic of Welsh onion concentrates.

Colloidal fouling in forward osmosis: Role of reverse salt diffusion

Boo, C.,Lee, S.,Elimelech, M.,Meng, Z.,Hong, S. Elsevier Scientific Pub. Co 2012 Journal of membrane science Vol.390 No.-

Colloidal fouling behavior in forward osmosis (FO) was investigated, focusing on the role of reverse salt diffusion. Two suspensions of silica nanoparticles, with average particle diameters of 24 and 139nm, were used as model colloidal foulants. To verify the effect of reverse salt diffusion on the colloidal fouling behavior, NaCl and LaCl<SUB>3</SUB> were employed as draw solutions because they exhibit different reverse diffusion rates. Our results suggest that in colloidal fouling of FO, salts diffuse from the draw to the feed solution and accumulate within the colloidal fouling layer that forms on the membrane surface. The accumulated salts result in a marked acceleration of cake-enhanced osmotic pressure (CEOP), which reduces the net osmotic driving force for permeate water flux. Fouling was not observed with the small, 24-nm particles because of the lack of substantial cake formation, but was notable for the 139-nm particles and for a feed containing a mixture of the 24 and 139nm particles. Our findings further indicate that colloidal fouling is enhanced under solution conditions (ionic strength and pH) within the colloidal cake layer that promote aggregation or destabilization of the silica particles. Colloidal fouling reversibility was also examined by varying the cross-flow velocity during the FO fouling runs. We showed that in the absence of colloidal particle destabilization/aggregation, the permeate flux during colloidal fouling in FO recovered almost completely when the cross-flow velocity was increased from 8.5 to 25.6cm/s. Our results suggest that reverse salt diffusion in FO is a key mechanism that controls colloidal fouling behavior as well as fouling reversibility. Therefore, minimization of reverse salt diffusion through the selection of proper draw solutes and optimization of FO membrane selectivity are important for minimizing colloidal fouling as well as enhancing FO operation efficiency.

역삼투막 공정에서 Direct Osmosis의 역방향 Flux 기초특성

강일모,독고석 대한상하수도학회 2011 상하수도학회지 Vol.25 No.3

In a desalination technology using RO membranes, chemical cleaning makes damage for membrane surface and membrane life be shortened. In this research cleaning technology using direct osmosis (DO) was introduced to apply it under the condition of high pH and high concentration of feed. When the high concentration of feed is injected to the concentrate side after release of operating pressure, then backward flow occurred from treated water toward concentrated for osmotic pressure. This flow reduces fouling on the membrane surface. Namely, flux of DO was monitored under pH 3, 5, 10 and 12 conditions at feed concentrations of NaCl 40,000 mg/L, 120,000 mg/L and 160,000 mg/L. As a result, DO flux in pH 12 increased about 21% than pH 3. DO cleaning was performed under the concentrate NaCl 160,000 mg/L of pH 12 during 20 minutes. Three kinds of synthetic feed water were used as concentrates. They consisted of organic, inorganic and seawater; chemicals of SiO2 (200 mg/L), humic acid (50 mg/L) and sodium alginate (50 mg/L), seawater. As a result, flux recovery showed 17% in organic fouling, 15% in inorganic fouling and 14% of seawater fouling after cleaning using DO under the condition of concentrate NaCl 160,000 mg/L of pH 12.

Potassium Pentane-1,3,3,5-tetracarboxylate 유도용질 합성 및 이를 이용한 정삼투 공정 응용

이혜진,최진일,권세이,김인철 한국막학회 2019 멤브레인 Vol.29 No.2

An organic citrate series draw solute was synthesized using diethyl malonate for forward osmosis. The structure of the final compound potassium pentane-1,3,3,5-tetracarboxylate was confirmed by 1 H-NMR and 13C-NMR analysis. Osmotic pressure, solubility, water permeability and reverse salt flux were measured for the properties of the draw solute. Forward osmosis results showed that the draw solute exhibited higher water flux than other draw solutes of trisodium citrate and tripotassium citrate. Reverse salt flux of all the organic daw solutes was much lower than that of NaCl. The osmotic pressure of the synthesized draw solute was 25% lower than that of NaCl. The solubility of the draw solute was 317 g/ 100 g water, which is 8.8 times higher than that of NaCl. A commercialized nanofiltration membrane was used for the recovery of the draw solute. The draw solute could be effectively recovered at low pressure. 정삼투 공정에 유용한 유도용질로서 diethyl malonate를 사용한 citrate 계열의 유기 화합물을 합성하였다. 최종적으로 얻은 potassium pentane-1,3,3,5-tetracarboxylate는 1 H-NMR과 13C-NMR을 통하여 확인하였다. 유도용질의 물성을 확인하기 위해 삼투압, 용해도, 수투과도, 역염 투과도를 측정하였다. 합성한 유도용액을 사용하여 정삼투 공정을 진행한 결과, 동일한 citrate 계열인 trisodium citrate 및 tripotassium citrate보다 높은 수투과량을 나타내었으며 염의 역확산 정도는 NaCl에비하여 매우 낮은 값을 나타내었다. 합성된 유도용질의 삼투압은 NaCl보다 약 25% 낮았으나 물에 대한 용해도는 NaCl의 8.8 배인 317 g/100 g water의 값을 나타내었다. 정삼투 종료 후 유도용질의 회수를 위해 상용화된 나노여과막을 사용하였고, 낮은 압력에서 효율적으로 회수가 가능하였다.

역삼투압 해수담수화(SWRO) 플랜트에서 독립변수의 다중공선성을 고려한 예측모델에 관한 연구

한인섭,윤연아,장태우,김용수 한국품질경영학회 2020 품질경영학회지 Vol.48 No.1

Purpose: The purpose of this study is conducting of predictive models that considered multicollinearity of independent variables in order to carry out more efficient and reliable predictions about differential pressure in seawater reverse osmosis. Methods: The main variables of each RO system are extracted through factor analysis. Common variables are derived through comparison of RO system # 1 and RO system # 2. In order to carry out the prediction modeling about the differential pressure, which is the target variable, we constructed the prediction model reflecting the regression analysis, the artificial neural network, and the support vector machine in R package, and figured out the superiority of the model by comparing RMSE. Results: The number of factors extracted from factor analysis of RO system #1 and RO system #2 is same. And the value of variability(% Var) increased as step proceeds according to the analysis procedure. As a result of deriving the average RMSE of the models, the overall prediction of the SVM was superior to the other models. Conclusion: This study is meaningful in that it has been conducting a demonstration study of considering the multicollinearity of independent variables. Before establishing a predictive model for a target variable, it would be more accurate predictive model if the relevant variables are derived and reflected.

Physico-chemical treatment applied to compost liquor: Feasibility study

Jeremy Gagnaire,Laurent Chapon,Philippe Moulin,Benoıt Marrot 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.4

Compost liquor was treated using a combination of physico-chemical processes: (i) lime precipitation, (ii)filtration on a rotary drum vacuum precoat filter, (iii) ultrafiltration, and (iv) reverse osmosis. Laboratory Jar tests showed the interest of using lime to precipitate compost liquor. Yields of ammonium removal up to 90% were obtained for an optimum lime concentration of 6 g L-1. A test was run at semi-industrial scale on 400 L of highly loaded compost liquor (COD: 15,800 mg L-1, ammoniacal pollution:18,433 mg NH4+-N L-1, conductivity: 74,000 mS cm-1) to demonstrate the potential of the treatment process proposed. Outstanding purification yields were obtained, especially 95% of COD removal and 93%of ammoniacal pollution removal.