• 한국수소및신에너지학회논문집
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• 제23권3호
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• pp.285-292
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• 2012

The integrated gasification combined cycle (IGCC) system is well known for its high efficiency compared with that of other coal fueled power generation system. IGCC offers substantial advantages over pulverized coal combustion when carbon capture and storage (CCS) is required. Commercial plants employ different types of quenching system to meet the purpose of the system. Depending on that, the downstream units of IGCC can be modeled using different operating conditions and units. In case with $CO_2$ separation and capture, the gasifier product must be converted to hydrogen-rich syngas using Water Gas Shift (WGS) reaction. In most WGS processes, the water gas shift reactor is the biggest and heaviest component because the reaction is relatively slow compared to the other reactions and is inhibited at higher temperatures by thermodynamics. In this study, tehchno-econimic assessments were found according to the quench types and operating conditions in the WGS system. These results can improve the efficiency and reduce the cost of coal gasification.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.362-362
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• 2023

한정된 수자원의 이용 및 관리로 매년 물 부족과 물 배분 의사결정 문제가 발생하고 있다. 50년간(1965~2014년) 수자원의 총량은 약 1.2배 증가한 반면 인구수 약 1.8배, 생·공·농업용수의 수요는 약 5배가 증가(국회입법조사처, 2018) 했을 뿐 아니라, 기후변화의 영향으로 인한 강수량의 변화와 지역별 편차가 커져 지속가능한 물관리 필요성이 증대되고 있다. 따라서 효율적인 물관리를 위해서는 관리부처가 분절되어 있는 물순환 계통의 데이터를 통합하는 것이 우선시되어야 하고 이를 통해 물순환 모니터링/평가/예측 기술을 개발할 수 있다. 본 연구에서는 생활용수 물순환 계통 통합 DB를 정의 및 구축하였다. 도시의 관점에서 물순환 시스템을 순차적으로 물 유입(수원~취수장)/전달(정수장~급수지역)/유출(하(폐)수처리장~방류구)의 개념으로 설정하고 DB정의서를 마련하였다. 연구대상지는 가뭄이 장기화가 되고 있는 전라남도중 물순환 계통이 비교적 단순한 네트워크로 형성되어 있는 함평군 도시지역으로 선정하였다. 연구 기간은 총 5년(2017년 1월 1일~2021년 12월 31일)이고 일 단위 실계측자료 위주의 원자료를 구축하였다. 이를 이상치 탐지, 제거, 대체의 과정을 거쳐 품질 보정하고 정제된 시계열 자료에 대한 특성 분석을 하였다. 그 결과, 물순환 계통 내 주요 지점 간의 상관관계 및 지연시간을 통한 물흐름의 시계열적 특성을 파악할 수 있었으며 모형의 적합도를 판단하는 데 활용되는 통계량과 유의미하지 않은 잔차의 자기상관성을 볼 때 물 유입-전달-유출의 단기 예측을 위한 ARIMA(Auto-regressive Integrated Moving Average) 모형의 구축도 가능할 것으로 판단되었다. 다만 여름철 발생하는 방류량의 첨두값을 설명하기 위해서는 강우에 의한 불명수 발생으로 증가하는 방류량을 묘사할 수있어야 하므로 향후에는 물순환계통 외 해당 지역의 불명수(강우 효과)도 하수 방류량의 주요 입력 요인으로 추가 검토할 필요가 있다.

• 한국조경학회지
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• 제41권5호
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• pp.68-77
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• 2013

세계적인 기후변화 영향은 한반도의 강우패턴 변화와 그로 인한 홍수와 폭설, 가뭄 등의 급격한 기상이변으로 나타나고 있다. 이에 국내외적으로 기후변화대응 관련 다양한 대안이 검토되고 있으며, 선진외국에서는 10여 년 전부터 저영향개발(LID)을 통한 수자원의 활용과 환경 친화적인 개발에 관심을 기울이고 있다. 국내에서도 일부 개발 사업에 LID 기법을 적용하는 계획을 추진하고 있으며, 관련 기술의 연구개발이 진행 중이다. 그러나 민간이 손쉽게 활용할 수 있는 제도 및 기술이전이 부족한 실정이며, LID 요소기술의 실효성 또한 충분히 합의되지 못한 현실이다. 이에 LID 요소기술 중 공동주택단지에 적용하기 용이한 요소기술을 분류하고, 그 중 침투기능을 수행하는 요소기술을 대상으로 공동주택단지 조경공간에 적용하고, 물순환 모의(SWMM 5.0)를 시행하고, 기술의 실효성을 검증하였다. 이를 위하여 각기 다른 지역의 공동주택단지 3개소를 대상으로 미국 EPA의 SWMM 5.0을 활용한 강우모의를 실시하고, LID기법 적용 전, 후의 물순환 모의(침투량, 지표증발량, 지표유출량)를 실시하였다. 녹지공간에서 LID 기술의 중요성은 빗물의 양적 질적 조절과 공동주택단지의 Amenity를 증진 시키는 역할이다. 공동주택단지의 물리적 한계를 이해하고 원활한 수순환 계통의 적용을 위하여 LID 통합관리기술(IMPs)을 적용해야 하며, 이를 위하여 조경, 건축, 토목, 환경전문가간의 저영향개발에 대한 기술적 통섭의 노력이 요구된다.

• 대기
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• 제28권2호
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• pp.141-151
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• 2018

The KIAPS global model and data assimilation system were extended to assimilate brightness temperature from the Sondeur $Atmosph{\acute{e}}rique$ du Profil $d^{\prime}Humidit{\acute{e}}$ Intertropicale par $Radiom{\acute{e}}trie$ (SAPHIR) passive microwave water vapor sounder on board the Megha-Tropiques satellite. Quality control procedures were developed to assess the SAPHIR data quality for assimilating clear-sky observations over the ocean, and to characterize observation biases and errors. In the global cycle, additional assimilation of SAPHIR observation shows globally significant benefits for 1.5% reduction of the humidity root-mean-square difference (RMSD) against European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS) analysis. The positive forecast impacts for the humidity and temperature in the experiment assimilating SAPHIR were predominant at later lead times between 96- and 168-hour. Even though its spatial coverage is confined to lower latitudes of $30^{\circ}S-30^{\circ}N$ and the observable variable is humidity, the assimilation of SAPHIR has a positive impact on the other variables over the mid-latitude domain. Verification showed a 3% reduction of the humidity RMSD with assimilating SAPHIR, and moreover temperature, zonal wind and surface pressure RMSDs were reduced up to 3%, 5% and 7% near the tropical and mid-latitude regions, respectively.

• 한국자동차공학회논문집
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• 제22권4호
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• pp.111-120
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• 2014

The aim of this study is to develop an integrated urea-SCR catalytic filter system for reducing soot and $NO_X$ emissions simultaneously in diesel engines. In this study, the characteristics of exhaust emissions relative to reactive activation temperature under four kinds of engine loads are experimentally investigated by using a four-cycle, four-cylinder, direct injection type, water-cooled turbo intercooler ECU common-rail diesel engine with the integrated urea-SCR $MnO_2-V_2O_5-WO_3/TiO_2/SiC$ catalytic filter system operating at three kinds of engine speeds. The urea-SCR reactor is used to reduce $NO_X$ emissions, and the catalytic filter system is used to reduce soot emissions. The reactive activation temperature is very important for reacting a reducing agent with exhaust emissions. The reactive activation temperatures in this experiment is applied to 523, 573 and 623 K. The fuel is sprayed by the pilot and main injections at the variable injection timing between BTDC $15^{\circ}$ and ATDC $1^{\circ}$ according to experimental conditions. It is found that the $NO_X$ conversion rate is the highest as 83.9% at the reactive activation temperature of 523 K in all experimental conditions of engine speed and load, and the soot emissions shown by the average reduction rate of approximately 93.3% are almost decreased below 0.6% in all experimental conditions regardless of reactive activation temperatures. Also, the THC and CO emissions by oxidation reaction of Mn, V and Ti are shown in the average reduction rates of 70.3% and 38% regardless of all experimental conditions.

• 대한토목학회논문집
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• 제34권5호
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• pp.1625-1638
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• 2014

최근 심화되고 있는 기후변화에 적응하고 도시의 물순환을 개선하기 위한 주요 전략으로 저영향 개발(Low Impact Development; LID)이 강조되고 있다. 저영향 개발의 효과적인 실현을 위해서는 도시계획과의 연계가 필수적이다. 그러나 국내에서는 아직 도시계획과 저영향 개발의 연계현황 분석과 연계방안에 대한 연구가 미흡한 상태이다. 이에 본 연구는 1) 현재 국내 도시계획 및 개발 관련 제도에서 저영향 개발에 대한 고려사항이 있는지 검토하고, 2) 도시계획의 기본방향과 전략을 제시하는 도시기본계획을 대상으로 계획분석 기법을 활용하여 저영향 개발과와의 연계성을 분석하여 그 방안을 제시하였다. 분석결과, 도시개발 관련 일부 사업지침에 저영향 개발이 반영되어 있으나, 선언적 수준의 내용만 포함되어 있어 도시계획 전반에 실질적 영향을 미치지는 못하고 있었다. 또한 7개 대도시의 도시기본계획을 대상으로 저영향 개발 계획요소와의 연계성을 검토한 결과, 획득가능점수의 약 19.52% (11.71점/60점)를 획득하여 현재까지는 도시기본계획에의 저영향 개발 반영 수준이 매우 낮으며, 도시 간 편차도 큰 것으로 나타났다. 도시계획 내 저영향 개발 주류화를 위해 저영향 개발을 주요 개발계획 원칙으로 명시하고, 부문별 계획에 비구조적, 구조적 저영향 개발 요소기술이 반영되도록 도시기본계획 수립지침이 개정될 필요가 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.2-11
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• 2006

In the processes of hydrological cycle, when precipitation reaches the ground surface, water may become surface runoff or infiltrate into soil and then possibly further percolate into groundwater aquifer. A part of the water is returned to the atmosphere through evaporation and transpiration. Soil moisture dynamics driven climate fluctuations plays a key role in the simulation of water transfer among ground surface, unsaturated zone and aquifer. In this study, a one-layer canopy and a four-layer soil representation is used for a coupled soil-vegetation modeling scheme. A non-zero hydraulic diffusivity between the deepest soil layer modeled and groundwater table is used to couple the numerical equations of soil moisture and groundwater dynamics. Simulation of runoff generation is based on the mechanism of both infiltration excess overland flow and saturation overland flow nested in a numerical model of soil moisture dynamics. Thus, a comprehensive hydrological model integrating canopy, soil zone and aquifer has been developed to evaluate water resources in the plain region of Huaihe River basin in East China and simulate water transfer among precipitation, surface water, soil moisture and groundwater. The newly developed model is capable of calculating hydrological components of surface runoff, evapotranpiration from soil and aquifer, and groundwater recharge from precipitation and discharge into rivers. Regional parameterization is made by using two approaches. One is to determine most parameters representing specific physical values on the basis of characterization of soil properties in unsaturated zone and aquifer, and vegetations. The other is to calibrate the remaining few parameters on the basis of comparison between measured and simulated streamflow and groundwater tables. The integrated modeling system was successfully used in the Linhuanji catchment of Huaihe plain region. Study results demonstrate that (1) on the average 14.2% of precipitation becomes surface runoff and baseflow during a ten-year period from 1986 to 1995 and this figure fluctuates between only 3.0% in drought years of 1986, 1988, 1993 and 1994 to 24.0% in wet year of 1991; (2) groundwater directly deriving from precipitation recharge is about 15.0% t of the precipitation amount, and (3) about half of the groundwater recharge flows into rivers and loses through evaporation.

• 한국농공학회논문집
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• 제63권6호
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• pp.1-16
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• 2021

Global warming due to climate change is expected to significantly affect the hydrological cycle of agriculture. Therefore, in order to predict the magnitude of climate impact on agricultural water resources in the future, it is necessary to estimate the water demand for irrigation as the climate change. This study aimed at evaluating the future changes in water demand for irrigation under two Shared Socioeconomic Pathways (SSPs) (SSP2-4.5 and SSP5-8.5) scenarios for paddy rice in Gimje, South Korea. The APEX-Paddy model developed for the simulation of paddy environment was used. The model was calibrated and validated using the H₂O flux observation data by the eddy covariance system installed at the field. Sixteen General Circulation Models (GCMs) collected from the Climate Model Intercomparison Project phase 6 (CMIP6) and downscaled using Simple Quantile Mapping (SQM) were used. The future climate data obtained were subjected to APEX-Paddy model simulation to evaluate the future water demand for irrigation at the paddy field. Changes in water demand for irrigation were evaluated for Near-future-NF (2011-2040), Mid-future-MF (2041-2070), and Far-future-FF (2071-2100) by comparing with historical data (1981-2010). The result revealed that, water demand for irrigation would increase by 2.3%, 4.8%, and 7.5% for NF, MF and FF respectively under SSP2-4.5 as compared to the historical demand. Under SSP5-8.5, the water demand for irrigation will worsen by 1.6%, 5.7%, 9.7%, for NF, MF and FF respectively. The increasing water demand for irrigating paddy field into the future is due to increasing evapotranspiration resulting from rising daily mean temperatures and solar radiation under the changing climate.

• 대기
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• 제29권4호
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• pp.343-353
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• 2019

The seasonal climatology of atmospheric rivers (ARs) and their effects on the seasonal precipitation and temperature in Korea are examined using the AR chronology obtained by a methodology based on the vertically integrated water vapor transport (IVT) in conjunction with a fine-scale gridded analysis of station precipitation and temperature. ARs are found to affect Korea most heavily in the warm season with minimal impacts in winter. This contrasts the AR effects in the western North America and the Western Europe that are affected most in winters. Significant portions of precipitation in Korea are associated with AR landfalls for all seasons; over 35% (25%) of the summer (winter) rainfall in the southern part of the Korean peninsula. The percentage of AR precipitation over Korea decreases rapidly towards the north. AR landfalls are also associated with heavier-than-normal precipitation events for all seasons. AR landfalls are associated with above-normal temperatures in Korea; the warm anomalies increase towards the north. The warm anomalies during AR landfalls are primarily related to the reduction in cold episodes as the AR landfalls in Korea are accompanied by anomalous southerlies/southwesterlies.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.131.1-131.1
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• 2010

This study was conducted for engineering optimization for the gasification process which is the key factor for success of Taean IGCC gasification plant which has been driven forward under the government support in order to expand to supply new and renewable energy and diminish the burden of the responsibility for the reduction of the green house gas emission. The gasification process consists of coal milling and drying, pressurization and feeding, gasification, quenching and HP syngas cooling, slag removal system, dry flyash removal system, wet scrubbing system, and primary water treatment system. The configuration optimization is essential for the high efficiency and the cost saving. For this purpose, it was designed to have syngas cooler to recover the sensible heat as much as possible from the hot syngas produced from the gasifier which is the dry-feeding and entrained bed slagging type and also applied with the oxygen combustion and the first stage cylindrical upward gas flow. The pressure condition inside of the gasifier is around 40~45Mpg and the temperature condition is up to $1500{\sim}1700^{\circ}C$. It was designed for about 70% out of fly ash to be drained out throughout the quenching water in the bottom part of the gasifier as a type of molten slag flowing down on the membrane wall and finally become a byproduct over the slag removal system. The flyash removal system to capture solid particulates is applied with HPHT ceramic candle filter to stand up against the high pressure and temperature. When it comes to the residual tiny particles after the flyash removal system, wet scurbbing system is applied to finally clean up the solids. The washed-up syngas through the wet scrubber will keep around $130{\sim}135^{\circ}C$, 40~42Mpg and 250 ppmv of hydrochloric acid(HCl) and hydrofluoric acid(HF) at maximum and it is turned over to the gas treatment system for removing toxic gases out of the syngas to comply with the conditions requested from the gas turbine. The result of this study will be utilized to the detailed engineering, procurement and manufacturing of equipments, and construction for the Taean IGCC plant and furthermore it is the baseline technology applicable for the poly-generation such as coal gasification(SNG) and liquefaction(CTL) to reinforce national energy security and create new business models.