• 상하수도학회지
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• 제32권1호
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• pp.1-10
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• 2018

Recently, interest in the development of alternative water resources has been increasing rapidly due to environmental pollution and depletion of water resources. In particular, seawater desalination has been attracting the most attention as alternative water resources. As seawater desalination consumes a large amount of energy due to high operating pressure, many researches have been conducted to improve energy efficiency such as energy recovery device (ERD). Consequently, this study aims to compare the energy efficiency of RO process according to ERD of isobaric type which is applied in scientific control pilot plant process of each $100m^3/day$ scale based on actual RO product water. As a result, it was confirmed that efficiency, mixing rate, and permeate conductivity were different depending on the size of the apparatus even though the same principle of the ERD was applied. It is believed that this is caused by the difference in cross-sectional area of the contacted portion for pressure transfer inside the ERD. Therefore, further study is needed to confirm the optimum conditions what is applicable to the actual process considering the correlation with other factors as well as the factors obtained from the previous experiments.

• 대한환경공학회지
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• 제38권5호
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• pp.255-268
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• 2016

기후변화는 현재 사용되고 있는 지표수 및 지하수 등의 담수자원 외에도 새로운 수자원을 확보해야할 필요성을 증가시켰다. 해수담수화 시장은 이러한 변화에 따라서 매년 급증하고 있는 상황이며, 이에 발맞추어 2007년 해수담수화 플랜트 사업단이 국내에서 출범하였다. 2014년에 종료된 해수담수화플랜트 사업단은 증발식 해수담수화 기술에 치우친 국내 기술을 역삼투방식 해수담수화 기술로 선회할 수 있도록 이끌었다. 현재 세계 최고의 역삼투방식 해수담수화 기술 에너지 효율성은 약 $3.5kWh/m^3$ 전후로 조사된다. 기장 플랜트의 수준은 $3.8{\sim}4.0kWh/m^3$ 수준으로 비록 세계 최고 수준에는 미치지 못하나, 선두권이라 하기에는 부족함이 없는 것으로 사료된다. 한편, 세계 역삼투방식 해수담수화 기술은 평준화 수준에 이른 것으로 사료되며, 에너지 저감을 위해 새로운 기술을 개발하고자 경쟁중이다. 미래 해수담수 시장에서 경쟁할 것으로 예상되는 기술로 정삼투공정, 막증발법 등이 있으며, 이를 위해 국내에서도 정역삼투 융합공정 개발, 막증발법 및 얍력지연삼투등의 기술개발을 진행중에 있다. 이를 통하여 국내 기술수준을 $2.5kWh/m^3$까지 낮출 것으로 기대된다.

• 기술사
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• 제42권6호
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• pp.47-52
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• 2009

According to increasing demand of water mainly due to the growth of population and increased water consumption, many countries either face or worry about the shortage of fresh water. Proportionately, importance and efforts of each country to develop the potable water has been gradually increasing as well. Among others, desalination of seawater has been developed to one of the solutions mainly from the middle east and other arid regions to produce large quantity of fresh water from seawater. We installed beach seawater collector wells to develop the filtered seawater supply for desalination in a refinery. We came to a conclusion that the beach seawater collector well is one of the recommendable alternatives of seawater pre-treatment for desalination applications with lower operating cost and higher efficiency.

• Environmental Engineering Research
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• 제24권2호
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• pp.347-353
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• 2019

Although membrane distillation (MD) has great promise for desalination of saline water sources, it is crucial to improve its thermal efficiency to reduce the operating cost. Accordingly, this study intended to examine the thermal energy efficiency of MD modules in a pilot scale system. Two different modules of hollow fiber membranes were compared in direct contact MD mode. One of them was made of polypropylene with the effective membrane area of $2.6m^2$ and the other was made of polyvinylidene fluoride with the effective membrane area of $7.6m^2$. The influence of operation parameters, including the temperatures of feed and distillate, feed flow rate, and distillate flow rate on the flux, recovery, and performance ratio (PR), was investigated. Results showed that the two MD membranes showed different flux and PR values even under similar conditions. Moreover, both flow rate and temperature difference between feed and distillate significantly affect the PR values. These results suggest that the operating conditions for MD should be determined by considering the module properties.

• 한국표면공학회지
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• 제40권1호
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• pp.44-56
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• 2007

Excavated archaeological iron artifacts are usually conducted the conservation treatment for removal of chloride ions in the corrosion products. However, some iron artifacts are corroded again even after the conservation treatment due to unremoved chloride ions. Therefore, it is important to prevent desalinized artifacts from the occurrence of corrosion after the treatment. In this paper, we investigated the characteristics of corrosion products on salinized iron artifacts and evaluated the variety of desalination methods such as autoclave, intensive washing and NaOH. It was also found that ${\beta}-FeOOH$ (Akaganeite) played an important role on the occurrence of corrosion and the treatment for removal of chloride ions. The extents of desalination were compared between the desalination methods. Results showed that the autoclave method represented the highest efficiency for desalination while the intensive washing method was the lowest.

• Environmental Engineering Research
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• 제23권4호
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• pp.474-484
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• 2018

The cleaning efficiency of reverse osmosis (RO) membranes inevitably fouled by organic foulants depends upon both chemical (type of cleaning agent, concentration of cleaning solution) and physical (cleaning time, flowrate, temperature) parameters. In attempting to determine the optimal procedures for chemical cleaning organic-fouled RO membranes, the design of experiments concept was employed to evaluate key factors and to predict the flux recovery rate (FRR) after chemical cleaning. From experimental results and based on the predicted FRR of cleaning obtained using the Central Composite Design of Minitab 17, a modified regression model equation was established to explain the chemical cleaning efficiency; the resultant regression coefficient ($R^2$) and adjusted $R^2$ were 83.95% and 76.82%, respectively. Then, using the optimized conditions of chemical cleaning derived from the response optimizer tool (cleaning with 0.68 wt% disodium ethylenediaminetetraacetic acid for 20 min at $20^{\circ}C$ with a flowrate of 409 mL/min), a flux recovery of 86.6% was expected. Overall, the results obtained by these experiments confirmed that the equation was adequate for predicting the chemical cleaning efficiency with regards to organic membrane fouling.

• 멤브레인
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• 제33권5호
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• pp.257-268
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• 2023

막 축전식 탈염 공정(membrane capacitive deionization, MCDI)은 이온교환막을 다공성 전극과 함께 사용하여 탈염 효율을 향상시킬 수 있는 CDI 공정의 변형이다. 이온교환막은 MCDI의 성능에 큰 영향을 미치는 핵심 구성요소이다. 본 연구에서는 MCDI의 탈염 효율을 크게 향상시킬 수 있는 이온교환막의 최적 제조 인자를 도출하고자 하였다. 이를 위해 PE 다공성 필름의 세공에 단량체를 충진하고 in-situ 광중합을 진행하여 세공충진 이온교환막(pore-filled ion-exchange membranes, PFIEMs)을 제조하였다. 실험 결과, 제조된 PFIEMs은 다양한 탈염 및 에너지 변환 공정에 적용할 수 있는 수준의 우수한 전기화학적 특성을 나타내었다. 또한, MCDI 성능과 막 특성 인자와의 상관성 분석을 통해 막의 가교도를 제어하여 막의 전기적 저항이 충분히 낮은 범위에서 이온 선택 투과성을 최대화하는 것이 MCDI의 성능 향상을 위해 가장 바람직한 막제조 조건이라는 결론을 얻었다.

• 한국막학회:학술대회논문집
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• 한국막학회 2002년도 제10회 하계 Workshop
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• pp.23-34
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• 2002

No Abstract, See Full-text

• 동력기계공학회지
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• 제16권3호
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• pp.5-9
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• 2012

Novel mechanisms for Energy Recovery Devices are proposed to diminish the pressure loss in the high-pressure reverse-osmosis system. In the beginning, the state-of-the-art in the design of Energy Recovery Devices is reviewed and the features of each model are investigated. The direct-coupled axial piston pump(APP) and axial piston motor(APM) showed 39% energy recovery at operating pressure of reverse osmosis desalination systems, 60 bar. Meanwhile, the developed PM2D model, in which APM pistons are arranged parallel to those of APP, is more compact and showed higher efficiency in a preliminary test. Loss-reduction mechanisms employing rod piston and double raw valve port are additionally proposed to enhance the efficiency and durability of the device.

• 상하수도학회지
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• 제27권4호
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• pp.445-456
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• 2013

In this study, desalination by electrodialysis with ion exchange membranes was applied to synthetic waters with various ion concentrations and also for ground waters from coastal areas in Korea. Electrodialysis performance on the synthetic solutions showed the similar tendency in operation time and current curves, i.e., shorter operation time and higher maximum current with increasing applied voltages. The ED results of synthetic waters with different ion compositions, i.e., $Na_2SO_4$, $MgSO_4$, $CaSO_4$, at the similar conductivity condition, i.e., $1,250{\mu}s/cm$ revealed that effects of mono- and divalent ions on water quality and performance in electrodialysis were different. The divalent ions had less efficiency in the ED compared to monovalent sodium ions and also divalent calcium ions showed better performance than Mg ions. The electrodialysis on the ground waters produced high quality of drinking water. The groundwater from SungRoe however showed a buildup of membrane resistance. Organic matter concentrations and great portions of divalent ions in the groundwater were possible causes of the deteriorated performance.