• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2053-2058
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• 2004

The pressurized light water cooled, medium power (330 MWt) SMART (System-integrated Modular Advanced ReacTor) has been under development at KAERI for a dual purpose : seawater desalination and electricity generation. The SMART design verification phase was followed to conduct various separate effects tests and comprehensive integral effect tests. The high temperature / high pressure thermal-hydraulic test facility, VISTA(Experimental Verification by Integral Simulation of Transient and Accidents) has been constructed to simulate the SMART-P (the one fifth scaled pilot plant) by KAERI. Experimental tests have been performed to investigate the thermal-hydraulic dynamic characteristics of the primary and the secondary systems. Heat transfer characteristics and natural circulation performance of the PRHRS (Passive Residual Heat Removal System) of SMART-P were also investigated using the VISTA facility. The coolant flows steadily in the natural circulation loop which is composed of the steam generator (SG) primary side, the secondary system, and the PRHRS. The heat transfers through the PRHRS heat exchanger and ECT are sufficient enough to enable the natural circulation of the coolant.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.201-201
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• 2019

세계적인 기상이변으로 가뭄발생 빈도 및 영향이 증가하고 있으며, 급속한 산업화로 사용 가능한 수자원이 점차 고갈되어 있어, 국내에서도 해수담수화(Seawater Desalination)는 새로운 대체수자원으로 많은 관심을 받고 있다. 해수담수에 필요한 에너지 약 50~70%는 역삼투(Reverse Osmosis) 공정에서 발생되며, 해수온도 및 염분도에 따라 많이 변동될 수 있으므로 국립해양조사원(KHOA)의 과거 20년 자료를 이용하여 해수담수화 시설물 위치에 따른 영향을 분석하였다. 해수담수화에 필요한 에너지는 막 제조사에서 제공하는 RO Projection Software를 적용하여 에너지 소모량을 평가하고, 이를 고려한 시설물 위치에 대한 평가 모델을 구축하였다. 기존 해수담수화 시설은 대규모 물 공급이 필요한 지역을 우선적으로 고려했기 때문에 시설물 위치에 대한 객관적인 평가기준 마련이 어려웠다. 그러나 해수담수화 플랜트는 한번 설치되면 장기적인 시설물 유지 및 관리가 필요함으로 경제성을 고려한 최적 입지의 선정은 매우 중요하다. 본 연구는 국립해양조사원의 수집된 자료를 바탕으로 해수담수화 시설물 입지선정을 정량적으로 평가함으로서, 시설물 위치에 대한 의사결정시 참고할 수 있는 기초자료로 활용될 것으로 기대한다.

• Environmental Engineering Research
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• v.15 no.3
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• pp.141-147
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• 2010

The objective of this study was to assess the biofouling characteristics of the Bacillus biofilm formed on reverse osmosis (RO) membranes. For the study, a sporogenic Bacillus sp. was isolated from the seawater intake to a RO process, with two distinct sets of experiments performed to grow the Bacillus biofilm on the RO membrane using a lab-scale crossflow membrane test unit. Two operational feds were used, 9 L sterile-filtered seawater and 109 Bacillus cells, with flow rates of 1 L/min, and a constant 800 psi-pressure and pH 7.6. From the results, the membrane with more fouling, in which the observed permeate flux decreased to 33% of its initial value, showed about 10 and 100 times greater extracellular polymeric substances and spoOA genes expressions, respectively, than the those of the less fouled membrane (flux declined to 20% of its initial value). Interestingly; however, the number of culturable Bacillus sp. in the more fouled membrane was about 10 times less than that of the less fouled membrane. This indicated that while the number of Bacillus had less relevance with respect to the extent of biofouling, the activation of the genes of interest, which is initiative of biofilm development, had a more positive effect on biofouling than the mass of an individual Bacillus bacterium.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.869-876
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• 2008

A thermocompressor is the equipment which compresses a vapor to a desired discharge pressure. Since it was first used as the evacuation pump for a surface condenser, it has been widely adopted for energy saving systems due to its high working confidence. In the present study, the geometrical analysis of the shape between the jet nozzle and the diffuser inlet, the drag force was calculated by means of the integrated equation of motion and the computational fluid dynamic (CFD) package called FLUENT. The computer simulations were performed to investigate the effects by the various suction flow rates, the distance from jet nozzle outlet to the diffuser inlet and the dimensions of the diffuser inlet section through the iterative calculation. In addition, the results from the CFD analysis on the thermocompressor and the experiments were compared for the verification of the CFD results. In the case of a jet nozzle, the results from the CFD analysis showed a good agreement with the experimental results. Furthermore, in this study, a special attention was paid on the performance of the thermocompressor by varying the diffuser convergence angle of $0.0^{\circ}$, $0.5^{\circ}$, $1.0^{\circ}$, $2.0^{\circ}$, $3.5^{\circ}$ and $4.5^{\circ}$. With the increase of the diffuser convergence angle. the suction capacity was improved up to the degree of $1.0^{\circ}$ while it was decreased over the degree of $1.0^{\circ}$.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.329-338
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• 2017

The problem of disposal of brine due to increased MD/RO desalination plant has recently become a big social issue. The chlor-alkali process through electrolysis of brine has been studied as a method to overcome this problem. In order to increase the electrolysis efficiency, a pretreatment process for removal of hard substances must be preceded. In this study, we investigated the mechanism of removal of hardness through chemical precipitation. As a result, Ca was greatly influenced by addition of $Na_2CO_3$, and Mg was strongly influenced by pH. Also, the addition of NaOH and $Na_2CO_3$ enabled simultaneous removal of Ca and Mg, and showed a removal efficiency of 99.9% or more. Finally, the residual concentrations of Ca and Mg in the brine after the reaction were 0.14 and 0.13 mg/L, respectively. Saturation index was calculated using Visual MINTEQ 3.1, and solid phase analysis of the precipitate was performed by FE-SEM and PXRD analysis. It was confirmed that precipitate formed by the formation of calcite and brucite.

• Membrane Journal
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• v.30 no.3
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• pp.190-199
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• 2020

The utilization of multiple water sources becomes important due to the master plan for development of water supply released by Ministry of Environment, Korea in 2018. In this study, therefore, the analysis of comprehensive effect in blending applicable water sources in Daesan where 100,000 ㎥/d seawater desalination plant will be constructed for industrial use was performed. The increase in mixing ratio of other water sources with seawater reduced salinity up to 50%, but negatively impacted the turbid and organic matter. Lab-scale reverse osmosis performance test also found that membrane fouling was exacerbated in blended water condition. The simulation results of reverse osmosis indicated 39% energy saving on average is expected at the one-to-one blending ratio, however, long-term performance test at the pilot-scale plant is highly required to evaluate the inclusive impact of mixing seawater and other water sources.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.11
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• pp.1103-1109
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• 2009

In this paper, the control of a membrane used in reverse osmosis desalination plant by using immune algorithm(IA) is addressed. The proposed algorithm IA of auto tuning method can find optimal gains and compared with conventional Ziegler-Nichols tuning method. The results of computer simulation represent that the proposed IA shows a good control performances better than Ziegler-Nichols tuning method.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.136-143
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• 2021

Pacific island countries, including Kiribati, are suffering from a shortage of essential resources as well as a reduction in their living space due to sea level rise and coastal erosion from climate change, groundwater pollution and vegetation changes. Global activities to solve these problems are being progressed by the UN's efforts to implement SDGs. Pacific island countries can adapt to climate change by using abundant marine resources. In other words, seawater plants can assist in achieving SDGs #2, #6 and #7 based on SDGs #14 in these Pacific island countries. Under the auspice of Korea International Cooperation Agency (KOICA), Korea Research Institute of Ships and Ocean Engineering (KRISO) established the Sustainable Seawater Utilization Academy (SSUA) in 2016, and its 30 graduates formed the SSUA Kiribati Association in 2017. The Ministry of Oceans and Fisheries (MOF) of the Republic of Korea awarded ODA fund to the Association. By taking advantage of seawater resource and related plants, it was able to provide drinking water and vegetables to the local community from 2018 to 2020. Among the various fields of education and practice provided by SSUA, the Association hope to realize hydroponic cultivation and seawater desalination as a self-support project through a pilot project. To this end, more than 140 households are benefiting from 3-stage hydroponics, and a seawater desalination system in connection with solar power generation was installed for operation. The Association grows and supplies vegetable seedlings from the provided seedling cultivation equipment, and is preparing to convert to self-support business from next year. The satisfaction survey shows that Tarawa residents have a high degree of satisfaction with the technical support and its benefits. In the future, it is hoped that SSUA and regional associations will be distributed to neighboring island countries to support their SDGs implementations.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.1
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• pp.55-60
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• 1988

A two year's field experiment was conducted on newly reclaimed saline tidal lands to measure the effects of sand mulching on salinity of the soils and their relationship to crop performance. Hybrid sorghum cv. Pioneer 931 was grown under different mulching treatments using of medium sand and red earth (Fine loamy, Typic Hapludults). Salinity in the root zone was decreased markedly under soil mulching using of medium sand, especially during the dry season, and it caused a great increase in the root growth and R/T ratio. Seasonal values of electrical conductivity at sand mulching were 6.6 in April and 1.6 mmhos in August, but it was still high with a concentration of 12.7 (April) and 3.8 mmhos (August) in untreated check plot. Sand mulching increased plant growth and the rate of dry matter accumulation. However, treatment of red earth additionally over sand mulching produced lower dry matter yield than those of soil mulching using of medium sand only. Under salt stress sorghum plant showed a decrease in the leaf weight ratio (LWR) and it resulted in a low concentration of crude protein of the plant. Sand mulching enhanced leaf weight ratio and rate of protein synthesis.

• Corrosion Science and Technology
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• v.7 no.1
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• pp.27-34
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• 2008

In industrial and fluid handling systems, frequently the protective film forming materials suffer from severe corrosion due to microbial effects. As an example, various micro-organisms, including bacteria, exist in seawater normally fed to power and desalination plants. Unless seawater intakes are properly disinfected to control these microbial organisms, biological fouling and microbial induced corrosion (MIC) will be developed. This problem could destroy metallic alloys used for plant construction. Seawater intakes of cogeneration plants are usually disinfected by chlorine gas or sodium hypochlorite solution. The dose of disinfectant is designed according to the level of contamination of the open seawater in the vicinity of the plant intake. Higher temperature levels, lower pH, reduced flow velocity and oxidation potential play an important role in the enhancement of microbial induced corrosion and bio-fouling. This paper describes, in brief, the different types of bacteria, mechanisms of microbiological induced corrosion, susceptibility of different metal alloys to MIC and possible solutions for mitigating this problem in industry. A case study is presented for the power plant steam condenser at Al-Taweelah B-station in Abu Dhabi. The study demonstrates resistance of Titanium tubes to MIC.