• 한국초전도ㆍ저온공학회논문지
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• 제21권2호
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• pp.22-25
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• 2019

The superconducting magnetic separation system has been developing to separate the iron oxide scale from the feed water of the thermal power plant. The accumulation in the boiler lowers the heat exchange rate or in the worst case damages it. For this reason, in order to prevent scale generation, controlling pH and redox potential is employed. However, these methods are not sufficient and then the chemical cleaning is performed regularly. A superconducting magnetic separation system is investigated for removing iron oxide scale in a feed water system. Water supply conditions of the thermal power plant are as follows, flow rate 400 t / h, flow speed 0.2 m / s, pressure 2 MPa, temperature $160-200^{\circ}C$, amount of scale generation 50 - 120 t / 2 years. The main iron oxide scale is magnetite (ferromagnetic substance) and its particle size is several tens ${\mu}m$. As the first step we are considering to introduce the system to the chemical cleaning process of the thermal power plant instead of the thermal power plant itself. The current status of development will be reported.

• 한국화재소방학회논문지
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• 제27권6호
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• pp.44-49
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• 2013

고강도/연성소재이면서 화학적으로 안정된 폴리에틸렌 소재가 배관으로 양산되면서 수도용 및 산업용으로 그 사용이 확산되고 있다. 최근에는 국내 플랜트에서도 기존 주철배관의 부식 누설 해소방안으로 고밀도 폴리에틸렌 배관이 사용되고 있는데, 각각의 플랜트 설계조건 및 운전조건을 적절히 고려하지 않을 경우 고밀도 폴리에틸렌 배관은 물리적인 손상이 유발될 수 있다. 폴리에틸렌 소재의 대구경 배관을 플랜트에 적용함에 있어 관련기준 및 설치 경험사례를 고찰한 결과, 수충격이 발생되는 환경에서 균열손상 가능성이 있어 폴리에틸렌 배관을 대구경 배관으로 사용시주의가 필요하다고 판단된다.

• 한국방재안전학회논문집
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• 제16권4호
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• pp.75-84
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• 2023

대다수의 개발도상국은 물수급 계획을 위한 수문 자료 부재로 장기유출량 산정이 불가능하며, 물 분배 의사결정을 진행하는데 합리적인 물수급 계획을 수립하기가 어려운 상황이다. 연구대상지역인 인도네시아 반둥지역은 급격한 도시화 및 인구집중으로 심각한 상수부족 상황이며 물수지 예측 방안이 구축되어 있지 않아 상수도 보급률이 약 20% 정도 수준이다. 이에 본 연구에서는 개발도상국에서의 물수지 예측접근방안을 제시하기 위해 MODSIM(Modified SIMYLD) 네트워크 모형 활용한 이수안전도 및 용수공급 가능량을 분석하였다. MODSIM 모형의 적정성을 검토하기 위해 비유량법을 적용하여 Pataruman 관측소의 19개년(2002~2020년) 유출량 자료를 기준으로 장기유출량을 산정하고 물수지 분석을 수행하였다. 분석결과 기존 월별 최적운영곡선과 일치하는 것을 확인할 수 있었다. 발전소의 발전용량을 분석한 결과 0.30~0.50% 정도 차이가 났으며, Pataruman 지점 이수안전도는 Q95% 유량 기준 1.64%, Q355 유량 기준 0.47% 높게 나타났다. 기존 저수지 최적운영곡선과 비교한 운영효율이 1% 내외로 유사하게 계측되어, 이를 통해 MODSIM 네트워크 모형을 이용한 용수공급 평가 가능성과 용수공급시설의 필요성을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1603-1604
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• 2007

The load of power plants changes every from time to time according to which steam flow of boiler changes. the feed water control is very important for the power plant to be operated in its stability conditions. In case of circulation type boiler, the instability of feed water control leads to instability of drum level control. The higher level of drum water can induce bad quality steam to go into turbine which means the possibility of damage. The lower level of drum water can induce the tubes of boiler water wall to be overheated. In case of once through type boiler, the instability of feed water control leads to bad cooling of superheaters. The less the feed water flow is, the more heated the superheater is. It is necessary for the turbine driving feed water pump to be controlled for the optimal feed water flow in the large capacity power plant. The speed of turbine is controled for the feed water flow. By the way, the optimal control of steam valve is necessary for the speed control of turbine. Therefore, the various kinds of the steam valve structures are introduced in this paper

• 한국자원식물학회지
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• 제11권3호
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• pp.307-314
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• 1998

The response of water stree under high and low temperatures, was shown differently according to the longer the suspension period of water supply. Leaf photosynthetic rate(LPS), leaf water potential(WP), relative leaf water content and relative soil water content were lower. At the higher temperatures, the percentate of reduction in LPS and WP was greater than at low temperatures. It is suggested that evaporation rate should be higher in the high temperature than the lower temperature. Also leaf water potential was lower at high temperature than at low temperature. After the 9 th day of treatment , LSP was remarkably reduced at high temperature, but the reduction of LPS was not significant at low temperature. Solidago virga-aurea var. asiatic that maintained LPS of 3rd day after treatment was more strong than other varieties at low temperatures. The silting and curling of leaves were observed symptoms of stress on the 9th day at the both temperatures. The leaves of aster scaber and Ligularia fischeri turned red on the 9th day after treatment at low temperature.

• 한국유체기계학회 논문집
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• 제20권1호
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• pp.53-58
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• 2017

This paper describes liquidity evaluation on the horizontal branch pipe connected to a food waste disposer and performance of five disposers marketed. Experimental apparatus for analyzing the five disposers has been introduced to measure vibration, sound level and power consumption of the disposers. Simulator for analyzing the required water velocity to avoid waste jam inside the pipe connected to a food waste disposer has been designed and constructed. The simulator can control some experimental parameters: pipe slope, disposer supply water quantity, food waste materials and operation time of a disposer. Throughout the experimental measurements of the disposers marketed, it is found that the time need to crash food waste is about 20 seconds on the average. At the same flow condition, increase rate of internal water velocity is accelerated as the pipe slope increases. The water velocity inside the pipe having 50 A and slope of 1/50 is 0.26 m/s when the water flowrate to supply the disposer is 16 l pm. Considering the specific gravity and adhesion property of food waste, water velocity of the horizontal branch pipe connected to a food waste disposer need to excess 0.26 m/s at least to avoid the waste blockage inside the pipe.

• 상하수도학회지
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• 제14권4호
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• pp.318-327
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• 2000

Sludge production from water treatment plants is increasing each year because water resources deterioration is proceeding and water supply facilities are growing due to water demand increase. Water treatment plant sludges can be modified to soil cover in sanitary landfilling site through the lime treatment and other alternatives. The compression strength of $1.0kg/cm^2$ is necessary for the dozer operation on soft son cover material at municipal landfilling site. Modified sludge was experimentally produced in this study with lime, bentonite, loess, and activated loess dosing. X-ray diffraction patterns of the limed water treatment plant sludge confirmed the presence of calcium carbonate and ettringite. Unconfined compression strength properties of modified sludges showed material property improvement applicable for soil cover alternatives. When adding 20-30% activated loess to water treatment plant sludges. the modified sludges could reach the compression strength for cover soil after 7 days solidification reaction, but decrease of compression strength was intentioned in 28 days reaction period. Solidification effect of the modified sludge with activated loess was observed through the scanning electron microscope.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.43-46
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• 2022

수용가에서 사용되는 수돗물의 패턴과 양을 정확하게 예측하여 필요한 만큼의 수돗물을 펌프를 이용하여 배수지로 전달하여 저장하고, 필요한 유량이 최소의 전기에너지를 이용하여 적기에 공급되어야 정수장의 최적화 운영을 할 수 있다. 본 논문에서는 수돗물 생산·공급의 안정성을 확보하기 위하여 AI 기반 복합센서를 실증지인 정수장에 적용하기 전에 사전검증할 수 있는 시스템을 구축하여 복합센서별 사전검증 모델을 통해 보완 사항을 도출하고, 제작 과정에 피드백하여 복합 센서 데이터의 품질 및 동작 안정성을 향상시키고자 하였다.

• 한국기후변화학회지
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• 제4권1호
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• pp.63-75
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• 2013

본 연구의 목적은 에너지 절감 및 온실가스 감축을 위해 수도사업장에 도입된 펌프 스케쥴링 시스템의 온실가스 감축 효과를 객관적으로 분석하는데 있다. 이 목적을 달성하기 위해서 온실가스 감축량 산정시 CDM 방법론 AMS-II.C/Version 13을 적용하였다. 베이스라인과 프로젝트 배출량을 산정하기 위해 사업 전후의 유량, 흡수정과 써지탱크의 수위 차, 전력량 데이터를 이용하였다. 감축량 산정의 정확성을 높이기 위해 펌프 운영과 연관성이 적은 소내 소비 전력과 계통손실도 고려하여 계산하였다. 본 연구에서 적용된 방법론과 계산식은 수도사업장에서 온실가스 감축을 위해 적용되는 타 기술의 감축량 산정 시에도 일정 부분 적용 가능할 것으로 판단된다.

• Journal of Advanced Marine Engineering and Technology
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• 제31권5호
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• pp.514-521
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• 2007

There has been considerable interest recently in the topic of renewable energy. This is primarily due to concerns about environmental impacts. Moreover, fluctuating and rising oil prices, increases in demand, supply uncertainties and other factors have led to increased calls for alternative energy sources. Small hydropower, especially using water supply system, attracts high attentions because of relatively lower cost and smaller space requirements to construct the plant. Moreover. newly developed positive displacement turbine has high acceptability for the system. Therefore, the purpose of this study is focused on the examination of the performance characteristics and proposition of a optimum design method of the turbine for the improvement of the performance. The results show that newly proposed optimum design method for the turbine has high accuracy of performance prediction and good applicability for the performance improvement of the turbine.