• 공업화학
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• 제34권5호
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• pp.507-514
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• 2023

촉매(Ag/γ-Al₂O₃) 충진형 유전체 장벽 방전 플라즈마 반응기를 이용한 질소산화물(NO_x)의 선택적 촉매 환원을 조사하였다. 촉매 상에서 간헐적으로 플라즈마를 발생시킬 때 NO_x의 환원제인 탄화수소가 부분 산화되어 알데하이드류를 생성하였으며, 알데하이드류의 높은 환원력으로 인해 촉매를 단독으로 사용한 경우에 비해 높은 NO_x 전환율을 보여주었다. 동일한 운전 조건(온도: 250 ℃; C/N: 8)에서 비교한 NO_x 저감 효율은 탄화수소(n-헵테인), 프로피온알데하이드, 뷰티르알데하이드에 대해 각각 47.5%, 92%, 96%로 나타났으며, 알데하이드류의 높은 질소산화물 환원 성능이 확인되었다. 간헐적 플라즈마 발생시 적정 조건을 파악하기 위하여, 고전압 on/off 주기를 0.5~3 min으로 조절하였고, 연속적인 플라즈마 발생의 경우와 동일한 에너지밀도에서 NO_x 저감 성능을 비교하였다. 고전압을 2 min 간격으로 on/off 하여 간헐적으로 플라즈마를 생성시켰을 때 연속적인 플라즈마 발생 대비 가장 높은 질소산화물 저감 효율이 얻어졌다. 동일한 에너지밀도에서도 간헐적 플라즈마 방전의 경우가 연속 플라즈마에 비해 높은 NO_x 저감 효율을 보이는 것은, 탄화수소가 분해되어 생성되는 알데하이드류 등의 중간생성물들이 NO_x 저감 반응에 보다 효율적으로 이용되었기 때문이다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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• pp.777-783
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• 2000

Composting by negative aeration is a reasonable proposition to control odor generated during composting process. Cattle manure and rice hulls mixtures were composted in a bin composting system by negative aeration. Continuous(CA) and intermittent(IA) aeration methods were applied to analyze the composting characteristics. The composting temperature and the ammonia emission during composting were investigated according to the aeration methods. The main problem for the negative aeration was the generation of condensate in the suction line of blower. The quantity of condensate was significant for continuous aeration. The aeration method should be modified to escape from the cooling effect of continuous aeration at the initial stage of composting. It took a longer time to finish a composting for intermittent aeration on account of lower aeration. It was concluded that the composting by negative aeration could be accomplished by either continuous or intermittent aeration method if the flow rate would be controlled more efficiently and the water vapor in suction line of blower could be removed effectively. Ammonia emission increased up to maximum value of 675ppm for continuous aeration while 300ppm for intermittent aeration. However, the cumulative value of ammonia emission was larger for intermittent aeration than for continuous aeration.

• Journal of Electrical Engineering and Technology
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• 제8권2호
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• pp.238-243
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• 2013

In this paper, a novel approach for optimized installation and operations of battery energy storage system (BESS) and electric double layer capacitor (EDLC) modules for the renewable energy based intermittent generation is presented for them to be connected with an electric power grid. In order to make use of not merely the high energy density of battery but also the high power density of EDLC modules, it is very useful to devise the hybrid system which combines BESS and EDLC modules. The proposed method adopts the linear programming to calculate the optimized capacity as well as the quadratic programming to transmit the optimal operational signals to BESS and EDLC modules. The efficiency of this methodology will be demonstrated in the experimental study with the real data of wind speed in Texas.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.351-355
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• 2009

There are two types of controller between railway and train. those are the Continuous Message Controller and the Intermittent Message Controller using for KHSR. The conventional Intermittent Message Controller board used a variable resister for setting the phase, but the variable resister affected some environmental facts, such as temperature, humidity, and vibration, etc. And It is requirement of reduction message processing time for speed-up operation in Next-Generation High-Speed Rail. This study suggests how to solve the problem described above. Using FPGA is quite profitable. It's easy to use and maintain, flexible with the New algorithm to fix up the problem.

• 상하수도학회지
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• 제38권1호
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• pp.29-38
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• 2024

Wastewater management is increasingly emphasizing economic and environmental sustainability. Traditional methods in sewage treatment plants have significant implications for the environment and the economy due to power and chemical consumption, and sludge generation. To address these challenges, a study was conducted to develop the Intermittent Cycle Extended Aeration System (ICEAS). This approach was implemented as the primary technique in a full-scale wastewater treatment facility, utilizing key operational factors within the standard Sequencing Batch Reactor (SBR) process. The optimal operational approach, identified in this study, was put into practice at the research facility from January 2020 to December 2022. By implementing management strategies within the biological reactor, it was shown that maintaining and reducing chemical quantities, sludge generation, power consumption, and related costs could yield economic benefits. Moreover, adapting operations to influent characteristics and seasonal conditions allowed for efficient blower operation, reducing unnecessary electricity consumption and ensuring proper dissolved oxygen levels. Despite annual increases in influent flow rate and concentration, this study demonstrated the ability to maintain and reduce sludge production, electricity consumption, and chemical usage. Additionally, systematic responses to emergencies and abnormal situations significantly contributed to economic, technical, and environmental benefits.

• Journal of Electrical Engineering and Technology
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• 제10권6호
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• pp.2211-2220
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• 2015

This paper analyzes multiple active management (AM) techniques of active distribution network (ADN), and proposes an optimal coordination model of intermittent distributed generation (IDG) accommodation considering the timing characteristic of load and IDG. The objective of the model is to maximize the daily amount of IDG accommodation under the uncertainties of IDG and load. Various active management techniques such as IDG curtailment, on-load tap changer (OLTC) tap adjusting, voltage regulator (VR) tap adjusting, shunt capacitors compensation and so on are fully considered. Genetic algorithm and Primal-Dual Interior Point Method (PDIPM) is used for the model solving. Point estimate method is used to simulate the uncertainties. Different scenarios are selected for the IDG accommodation capability investigation under different active management schemes. Finally a modified IEEE 123 case is used to testify the proposed accommodation model, the results show that the active management can largely increase the IDG accommodation and penetration.

• KEPCO Journal on Electric Power and Energy
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• 제6권4호
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• pp.433-438
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• 2020

Accurate forecasting of wind power is important for grid operation. Wind power has intermittent and nonlinear characteristics, which increases the uncertainty in wind power generation. In order to accurately predict wind power generation with high uncertainty, it is necessary to analyze the factors affecting wind power generation. In this paper, 6 factors out of 11 are selected for more accurate wind power generation forecast. These are wind speed, sine value of wind direction, cosine value of wind direction, local pressure, ground temperature, and history data of wind power generated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집
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• pp.33-37
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• 2004

Photovoltaic energy and wind energy are highly dependent on the season, time and extremely intermittent energy sources. Because of these reasons, in view of the reliability the photovoltaic and the wind power generation system have many problems(energy conversion, energy storage, load control etc.) comparing with conventional power plant. In order to solve these existing problems, hybrid generation system composed of photovoltaic(500W) and wind power system(400W) was suggested But, hybrid generation system cannot always generate stable output due to the varying weather condition So, the auxiliary power compensation unit that uses elastic energy of spiral spring was added to hybrid generation system for the present study. It was partly confirmed that hybrid generation system was generated a stable outputs by spiral spring was continuously provided to load.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.303-306
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• 2008

The wind power generation systems have a fluctuating or intermittent power output due to the variability of the wind speed. The amount of wind generation which can be connected to the grid without causing voltage stability problems is limited. In this study, the simulation of the wind power generation including energy storage system were performed to reduce the fluctuation of wind power output and to obtain the optimal operation planning of energy storage system.

• 조명전기설비학회논문지
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• 제25권5호
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• pp.45-53
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• 2011

This paper presents a novel random sampling method for generation adequacy assessment including wind-power. Although a time sequential sampling has advantages than a random sampling in its assessment results, it takes long assessment time. Therefore, an effective random sampling method for generation adequacy assessment is highly recommended to get specific reliability indices quickly. The proposed method is based on the Monte-Carlo simulation with state sampling and it can be applied to generation adequacy assessment with other intermittent power sources.