• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.663-664
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• 2016

해수를 이용한 온도차 발전은 심층수와 표층수의 온도 차이를 이용한 암모니아(냉매)를 사용하여 폐쇄적인 액화와 기화를 반복하여 터빈을 돌리는 방식이다. 온도차 발전의 특성상 온도 차이가 클수록 에너지 발전 특성은 좋아진다. 이는 심층수 표층수의 온도차이가 커야 됨을 이야기 한다. 하지만 겨울이 되면 표층수와 심층수의 온도차이가 크지 않아 에너지 효율이 떨어지는 문제점이 있다. 그리고 해수 담수화기술은 지구의 97%를 차지하지만 우리가 먹을 수 없는 바닷물을 담수로 바꾸는 기술로, 해수 담수화기술로 생산된 담수는 선박내의 공업, 식수 등 각종 용수로 사용할 수 있다. 본 논문에서는 현재 문제가 되고 있는 계절에 따른 표층수의 온도 변화를 개선하기 위해 기존에 사용하고 있는 선박용 디젤엔진의 열에너지와 LNG의 냉열 에너지를 사용한 온도차 발전을 위해 LNG 운송 선박을 기준으로 LNG 운송 선박 하이브리드 엔진에 관한 연구와 냉열 에너지를 활용한 해수 냉동법으로 담수화하는 발전 및 담수화를 복합시킨 연구를 제시하고자 한다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1094-1100
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• 2014

오폐수처리, 해수담수화 및 식품산업의 경우 증발과정은 필수공정이며, 이는 기본적으로 용액으로부터 용매인 순수한 물성분을 추출하여 점차 용액의 농도를 증가시키는 방식이다. 농축을 위한 방식은 전기투석, 증발식, 막방식 등의 다양한 방법이 사용되고 있으나, 본 연구에서는 여러 산업분야에서 적용되고 있는 증발식을 대상으로 운전방식에 따른 가열열원의 소모량을 이론적으로 분석하고, 이에 근거하여 다단증발식 해수담수화설비의 운전특성을 파악하였다. 본 연구의 결과에 따르면 시스템에서 이용할 수 있는 전체 온도차, 즉 인입해수의 온도와 1단 증발부로 유입되는 해수온도와의 차를 기준으로 증발단의 수를 증가시킬수록 에너지효율이 상승함을 알 수 있었다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.3-9
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• 2008

Recently, the plant industries are being activated and plant control systems use various technologies. Because the optimized design for the plants is very important for the reducing of operation and maintenance costs, automatic control systems become more important. Plant control systems consist of the master controller, the plant networks, the programming environment for engineering, monitoring software and the field devices. The control systems should have reliability, availability and safety. Modular architecture of hardware and software makes flexible configuration of the control systems. Each component should have diagnostic functions. It follows industrial standards and makes open systems. Open systems increase accessibility against the data which is distributed in the plants. The controllers including processor and communication modules use the up-to-date technology. They have real time and fault tolerant function by duplicating processors or networks. It also enables to make the distributed control systems. The distributed architecture makes more scalable main control system. Automatic control systems can be operated with better performance. In this paper, we analyzed the requirements of the seawater desalination plants and made some consideration facts for developing the optimized controller. Also we described the design concept of the main controller, which consists of several modules. We should validate and complement the design for the reliability and better performance.

• 한국시뮬레이션학회논문지
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• 제28권4호
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• pp.1-10
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• 2019

해수담수화(SWRO, Sea Water Reverse Osmosis) 플랜트는 장기적이고 지속적인 담수 생산을 위하여 설계단계부터 플랜트의 가용도를 고려하여야 하며, 시간의 흐름에 따라 다양한 형태의 노후 현상이 진행되어 시스템 성능의 저하가 발생하므로 가용도 유지를 위한 고장정비 및 예방정비 계획 수립 등이 필요하다. 해수담수화 플랜트와 같이 복잡한 공학구조로 구성된 플랜트 분야에서는 시스템의 신뢰도 혹은 가용도를 수리적인 방법으로 추정하는데 어려움이 있다. 본 연구는 해수담수화 플랜트에 특화된 소프트웨어 개발을 위하여, RAM 분석 프레임워크와 모델링 방법을 개발하고, 가용도 산출을 위한 이산사건 시뮬레이션 모델을 제안한다. 플랜트 정비의 특성을 고려하여 고장 정비 발생 시, 단일 부품의 수리/교체 뿐만 아니라 분해 정비 수준에 따라 접근 가능한 모든 부품을 동시 정비하는 예방정비 정책을 제안하고, 제안된 방법론에 따라 시뮬레이션 모델 및 프로토타입을 개발하였다. 이를 활용하여 국내외에 건설된 해수담수화 플랜트의 현장 데이터를 기반으로 시스템의 가용도 및 가동률 등을 추정 사례 연구를 수행하였고, 그 결과 실제 플랜트의 가용도와 근접한 결과를 얻었다.

• 공업화학
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• 제27권4호
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• pp.386-390
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• 2016

축전식 탈염전극의 에너지 효율을 향상시키기 위하여 탄소나노튜브를 불소화 표면처리하고 이를 도전재로 적용하였다. 탄소나노튜브는 상온에서 불소와 질소의 혼합가스로 불소화 처리되었으며, 미처리 탄소나노튜브와 불소화 탄소나노튜브를 각각 활성탄소 대비 0~0.5 wt% 첨가하여 활성탄소 기반 축전식 탈염전극을 제조하였다. 불소화 탄소나노튜브는 미처리 탄소나노튜브에 비하여 전극 슬러리 및 전극 내에서 분산성이 향상된 것을 제타 전위와 전자주사현미경을 통해 확인하였다. 불소화 탄소나노튜브를 첨가한 전극은 미처리 탄소나노튜브를 첨가한 전극보다 전체적으로 높은 탈염효율을 보였으며, 에너지 소비량 역시 감소하였다. 이는 불소화 표면처리로 인한 탄소나노튜브의 분산성 향상으로 인해 축전식 탈염 전극의 저항이 감소되었기 때문이다.

• 한국물환경학회지
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• 제38권3호
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• pp.143-149
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• 2022

Membrane distillation (MD) has emerged as a sustainable desalination technology to solve the water and energy problems faced by the modern society. In particular, the surface wetting properties of the membrane have been recognized as a key parameter to determine the performance of the MD system. In this study, a novel surface modification technique was developed to induce a Janus-type hydrophilic/hydrophobic layer on the membrane surface. The hydrophilic layer was created on a porous PVDF membrane by vapor phase polymerization of the pyrrole monomer, forming a thin coating of polypyrrole on the membrane walls. A rigid polymeric coating layer was created without compromising the membrane porosity. The hydrophilic coating was then followed by the in-situ growth of siloxane nanoparticles, where the condensation of organosilane provided quick loading of hydrophobic layers on the membrane surface. The composite layers of dual coatings allowed systematic control of the surface wettability of porous membranes. By the virtue of the photothermal property of the hydrophilic polypyrrole layer, the desalination performance of the coated membrane was tested in a solar MD system. The wetting properties of the dual-layer were further evaluated in a direct-contact MD module, exploring the potential of the Janus membrane structure for effective and low-energy desalination.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.23-28
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• 2004

Various merchandises have appeared in recent markets of mineral water, beverage, food and cosmetics etc. These are almost manufactured by adding raw seawater, desalinated water, brine or salt from Deep Ocean Water(DOW), and it intimated desalination and mineral extraction are key techniques for DOW business. This study aims to verify the functional performance of mineral-controlled water produced by the basic methods which were proposed by authors for industrial purposes. This water revealed the possibility of the radical scavenging effects and moisturizing capability.

• Membrane and Water Treatment
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• 제2권3호
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• pp.159-173
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• 2011

The air gap membrane distillation (AGMD) process was applied for water desalination. The main objective of the present work was to study the heat and mass transfer mechanism of the process. The experiments were performed on a flat sheet module using aqueous NaCl solutions as a feed. The membrane employed was hydrophobic PTFE of pore size 0.22 ${\mu}m$. A mathematical model is proposed to evaluate the membrane mass transfer coefficient, thermal boundary layers' heat transfer coefficients, membrane / liquid interface temperatures and the temperature polarization coefficients. The mass transfer model was validated by the experimentally and fitted well with the combined Knudsen and molecular diffusion mechanism. The mass transfer coefficient increased with an increase in feed bulk temperature. The experimental parameters such as, feed temperature, 313 to 333 K, feed velocity, 0.8 to 1.8 m/s (turbulent flow region) were analyzed. The permeation fluxes increased with feed temperature and velocity. The effect of feed bulk temperature on the boundary layers' heat transfer coefficients was shown and fairly discussed. The temperature polarization coefficient increased with feed velocity and decreased with temperature. The values obtained were 0.56 to 0.82, indicating the effective heat transfer of the system. The fouling was observed during the 90 h experimental run in the application of natural ground water and seawater. The time dependent fouling resistance can be added in the total transport resistance.

• Membrane and Water Treatment
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• 제2권3호
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• pp.147-158
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• 2011

Membrane distillation process was used for desalination of hot (333 K) geothermal water, which was applied in the plant producing heating water. The investigated water contained 120 g salts/$dm^3$, mainly NaCl. The mineral composition was studied using an ion chromatography method. The obtained rejection of solutes was closed to 100%, but the small amounts of $NH_3$ also diffused through the membrane together with water vapour. However, the composition of obtained distillate allowed to use it as a makeup water in the heating water system. The geothermal water under study was concentrated from 120 to 286 g NaCl/$dm^3$. This increase in the solution concentration caused the permeate flux decline by a 10-20%. The geothermal water contained sulphates, which was subjected to two-fold concentration to achieve the concentration 2.4-2.6 g $SO{_4}{^{2-}}/dm^3$ and the sulphates then crystallized in the form of calcium sulphate. As a results, an intensive membranes scaling and the permeate flux decline was observed. The XRD analysis indicated that beside the gypsum also the NaCl crystallites were deposited on the membrane surfaces. The fresh geothermal water dissolved the mixed $CaSO_4$ and NaCl deposit from the membrane surface. This property can be utilized for self-cleaning of MD modules. Using a batch feeding of MD installation, the concentration of geothermal water was carried out over 800 h, without significant performance losses.

• Membrane and Water Treatment
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• 제2권1호
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• pp.1-24
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• 2011

The deficiency of clean water is a major global concern because all the living creatures rely on the drinkable water for survival. On top of this, abundant of clean water supply is also necessary for household, metropolitan inhabitants, industry, and agriculture. Among many purification processes, advances in low-energy membrane separation technology appear to be the most effective solution for water crisis because membranes have been widely recognized as one of the most direct and feasible approaches for clean water production. The aim of this article is to give an overview of (1) two new emerging membrane technologies for water reuse and desalination by forward osmosis (FO) and membrane distillation (MD), and (2) the molecular engineering and development of highly permeable hollow fiber membranes, with polyvinylidene fluoride (PVDF) and polybenzimidazole (PBI) as the main focuses for the aforementioned applications in National University of Singapore (NUS). This article presents the main results of membrane module design, separation performance, membrane characteristics, chemical modification and spinning conditions to produce novel hollow fiber membranes for FO and MD applications. As two potential solutions, MD and FO may be synergistically combined to form a hybrid system as a sustainable alternative technology for fresh water production.