전산유동해석을 이용한 500MWe 표준화력 보일러의 유량 불균형에 따른 연소 및 열전달 특성 분석

조현빈(Hyunbin Jo),박종근(Jongkeun Park),홍준석(Joonseok Hong),류창국(Chankook Ryu) 한국연소학회 2020 KOSCOSYMPOSIUM논문집 Vol.2020 No.9

화력발전 보일러 출구 NOx 농도 선행 예측을 위한 딥 러 닝 모델

조현빈(Hyunbin Jo),강동협(Donghyup Kang),박성민(Seongmin Park),이종욱(Jongwuk Lee),류창국(Changkook Ryu) 한국환경에너지공학회 2022 한국열환경공학회 학술대회지 Vol.2022 No.2

석탄화력에 서의 NOx 발생 최소화는 미세먼지 저감을 위한 주요 이슈 중 하나인데, 최근 신재생 에너지 공급 중가론 석탄 화력의 잦은 출력 변동으로 인해 질소산화물 저감 설비인 SCR(Selective Catalytic Reaction) 의 운전이 더욱 고도화될 필요가 있다. SCR의 암모니아 투입량은 보일러 연소 배가스의 유량과 NOx 농도에 의해 결정되는데, 효율적인 유량 제어를 위해 빠르고 정확하게 보일러 연소 배가스의 NOx 농도를 취득하는 것이 중요하다. 본 연구에서는 석탄화력의 운전 데이터를 이용하여 보일러 출구의 NOx 농도를 실시간으로 선행 예 측하는 딥러닝 모델 및 방법론을 개발했다. 연구 대상 설비는 한국형 표준화력으로 500MWe 급 접선연소식 보일러 이며, 모델 학습 및 평가에 사용된 운전 정보는 약 5개월 동안 81개 항목의 1분 간격의 데이터이다. 수집된 데이터는 전처리를 통해 석탄 공급량, 공기량, 버 너 각도 등을 포함한 19개의 입력 변수로 압축하였고, 데이터 특성에 맞는 딥러닝 모델을 조합하여 1분 후의 보일러 출구에서의 NOx를 포함한 산소 농도와 배가스 온도를 예 측하는 모델을 구성하였다. 모델 예측 성능을 분석한 결과, 본 연구에서 개발한 학습 기법을 이용하여 보일러 출구값을 예측하는 경우 기촌 모델들과 비교하여 평균적으로 약 40%의 예측 성능 향상을 보였다. 따라서, 이룰 기반으로 SCR 설비 운전의 최적화가 가능하며, 소각로 등 유사한 고체연료 연소로의 탈질설비 성능 최적화에 도 적용할 수 있을 것으로 예상된다

탈질설비 제어 최적화를 위한 딥러닝 기반 SCR 출구 NOx, NH₃ 농도 선행 예측 모델

조현빈(Hyunbin Jo),강동협(Donghyup Kang),박성민(Seongmin Park),이종욱(Jongwuk Lee),류창국(Changkook Ryu) 한국연소학회 2023 KOSCOSYMPOSIUM논문집 Vol.2023 No.5

500MWe 접선연소식 석탄 보일러의 NOx 저감을 위한 SOFA 최적화 연구

조현빈(Hyunbin Jo),강기섭(Kiseop Kang),박종근(JongKuen Park),류창국(Changkook Ryu),안현수(Hyunsoo Ahn),고영건(Younggun Go) 한국연소학회 2019 KOSCOSYMPOSIUM논문집 Vol.2019 No.5

This study investigated the optimization of separated overfire air (SOFA) on combustion and NOx emission in a retrofitted tangential-firing boiler at a 500 MWe capacity. Computational fluid dynamic (CFD) simulations incorporating advanced coal combustion models were performed for two operating parameters of the boiler. First, the flow rate of SOFA was varied between 15% and 35% of the total air while the flow rate of CCOFA (Close-coupled overfire air) was fixed at 5%. Second, the proportion of SOFA was varied from 0% to 25% while holding the flow rate of total OFA was fixed at 25%. When compared with the operation data, the CFD results showed reasonable agreement in terms of the heat distribution of the boiler and NOx emission for the reference case. The NOx emission at the furnace exit was reduced by up to 33% but unburned carbon in fly ash was increased by 3 times when the flow rate of SOFA increased to 35%. When the total OFA was fixed at 25%, increasing the SOFA reduced both the NOx emission and unburned carbon up to a ceratin proportion, and then increased them. This suggests that the combustion air distribution can be optimized between SOFA and CCOFA for reduction of both NOx and unburned carbon.

콘크리트의 소수성 표면처리를 통한 철강 보강재의 내식성 향상

조현빈(Hyunbin Jo),신동민(Dongmin Shin),서은혜(Eunhye Seo),이욱진(Wookjin Lee),이정훈(Junghoon Lee) 한국표면공학회 2020 한국표면공학회지 Vol.53 No.6

Corrosion of reinforcement steel rebar is a serious problem in a wide range of concrete application for buildings and infrastructures. Hydrophobizing surface treatments, such as self-assembled monolayer coating, edible oil-impregnation and silicone oil-impregnation were applied to solidified concrete. The hydrophobizing of concrete significantly reduces an absorption and transportation of water toward a steel rebar in concrete, so that the corrosion resistance of the steel rebar. In particular, the silicone oil-impregnation not only forms the hydrophobic monolayer on the concrete but also fills the inter-connected pores of concrete, thus the corrosion of steel rebar is significantly inhibited compared to the self-assembled monolayer coating and edible oil-impregnation. Therefore, the silicone oil-impregnation can be a promising candidate for preventing corrosion of steel rebar in concrete for durable performance and safety.

딥러닝 기반 화력발전 보일러 출구 NOx 농도 선행 예측 모델

조현빈(Hyunbin Jo),강동협(Donghyup Kang),박성민(Seongmin Park),이종욱(Jongwuk Lee),류창국(Kang Y. Huh) 한국연소학회 2022 KOSCOSYMPOSIUM논문집 Vol.2022 No.11

In this study, we developed a deep learning model to forecast the NOx and oxygen concentration, and gas temperature at the boiler exit of a coal-fired power plant. The target boiler is a 500 MWe tangential firing boiler, which is one of 20 units often referred to as standard coal power plant. From the database of the power plant, 73 raw items of operation data with one-minute frequency were collected for a period of approximately 5 months. Through the feature selection procedure, the raw data items were condensed into 19 features which include coal feeder throughput to burners, air flow rate, and burner tilt. The features were then used to establish two types of data segments: segment #1 for current operation status and segment #2 for recent histories measured at the boiler exit. Considering the large fluctuations, the histories of the recent values at the boiler exit values were averaged over 5 min. After evaluating different prediction models with respect to the nature of the data segments, suitable models were applied in the form of ensemble model to forecast the boiler exit values 1 min in advance. When compared to measured data, the prediction quality was sufficiently high with a mean square error of 0.0123 for NOx emission.

500MWe 접선연소식 보일러의 좌우 유량 불균형에 따른 열유동 및 NOx 배출 특성 CFD 해석

조현빈(Hyunbin Jo),박종근(Jongkeun Park),류창국(Changkook Ryu),홍준석(Joonseok Hong) 한국열환경공학회 2020 한국열환경공학회 학술대회지 Vol.2020 No.추계

석탄화력 내 암모니아 혼소율에 따른 연소 및 NOx 발생 특성에 대한 전산해석 연구

강우석(Woosuk Kang),조현빈(Hyunbin Jo),류창국(Changkook Ryu) 한국연소학회 2021 KOSCOSYMPOSIUM논문집 Vol.2021 No.11

This study analyze the combustion and NOx emission characteristic of NH₃ cofiring in a commercial pulverized coal boiler using computational fluid dynamics (CFD). Four different methods of NH3 supply at a cofiring ratio of 10% on a higher heating value(HHV)-based thermal input were evaluated while fixing total stoichiometric ratio at 1.08 and that for the burner zone at 0.84. In addition to advanced coal conversion models, global reaction mechanism for NH₃ combined with fuel and thermal NOx mechanisms was established for preliminary evaluation of NH₃ cofiring. For the reference case, the CFD results showed reasonable agreement with the operation data in terms of heat distribution and NOx emission. When NH3 was cofired, the total heat absorption significantly decreased by lower flame temperatures. However, the boiler efficiency was similar on a lower heating value (LHV) base. Therefore, the thermal input of NH₃ and corresponding boiler effienciy need to be determined using the LHV. NOx emission increased by NH₃ cofiring but significant differences were observed between the cofiring method. In particular, concentrating NH₃ supply in a particular burner level exhibited lower NOx emission, indicating that NH₃ cofiring method can be optimized to reduce the NOx emission. The NOx emission required further investigations with an improve NH₃ combustion model.

대향류 석탄화력 보일러의 NOx 저감을 위한 다단 OFA 및 CH₄ lancing 성능 평가

강우석(Woosuk Kang),조현빈(Hyunbin Jo),류창국(Changkook Ryu),이종국(Jongwook Lee) 한국연소학회 2021 KOSCOSYMPOSIUM논문집 Vol.2021 No.5

This study evaluate the performance of multi-level overfire air (OFA) and CH₄ lancing on combustion and NOx reduction in an opposed wall-firing boiler. Computational fluid dynamics (CFD) incorporating advanced coal combustion models was applied to evaluate two design parameters while fixing total stoichiometric ratio (SR) at 1.15 and that for the burner zone at 0.89. First, the OFA was modified into two levels (OFA1 and OFA2) and the flow rate distribution between them was evaluated. Second, the amount of CH₄ injected at the burners was varied between 0% and 20% of thermal input partially replacing that of coal. For the reference case, the CFD results showed reasonable agreement with the design data in terms of heat distribution and NOx emission. The NOx emission was reduced by 9% when OFA2 was used alone, the peak gas temperature entering the heat exchanger zone decreased by 25 ℃. When the thermal input of CH₄ was 10%, the NOx emission was reduced by 22% and the peak gas temperature was decreased by 5 ℃. All cases showed satisfactory carbon conversion, except for the case with a thermal input of CH₄ at 20%. The results suggest that the introduction of multi-level OFA and CH₄ lancing can be effective measures for NOx reduction without deteriorating the boiler performance.

얕은 습지에서 환경 요인에 따른 어류상 분포 특성

최종윤 ( Jong Yun Choi ),조현빈 ( Hyunbin Jo ),김성기 ( Seong Ki Kim ),라긍환 ( Geung Hwan La ),주기재 ( Gea Jae Joo ) 한국환경생태학회 2015 한국환경생태학회지 Vol.29 No.3

얕은 습지에서 환경 요인에 대한 어류의 분포와 종 조성을 평가하기 위해, 2012년 봄철(5~6월)에 경상남도에 위치한24개의 습지에서 이화학적 요인, 수생식물, 어류 등을 조사하였다. 조사 기간 동안 20종의 어류가 동정되었으며,잉어과 어류가 가장 우점하는 것으로 나타났다. 이화학적 요인 및 수생식물 생물량은 조사 지점에 따라 상이하였으며,특히 수생식물 생물량은 어류 풍부도와 매우 밀접하게 관련되었다(df=1, F=32.00, P=0.001). 조사 지점간에 군집 분석을 수행한 결과, 조사 지점들은 3개의 집단으로 구분되었으며, 이 또한 수생식물 생물량에 대한 영향으로 분석되었다. 첫 번째 집단의 습지에서는 검정우럭과 어류인 블루길에 의해서 우점되었으며, 그 외 어류 군집은 거의 출현하지않았다. 두 번째 집단은 주로 잉어과 어류인 붕어가 우점한다는 점에서 첫 번째 집단과 차이를 보였다. 세 번째 집단에 속한 습지에서는 첫 번째 집단과 비슷하게, 블루길이 우점하였으나, 다른 어류 종 또한 다양하게 출현하였다. 결론적으로 얕은 습지에서 어류 군집의 분포와 종 다양성은 수생식물의 생물량에 의해 강하게 영향 받는 것으로 평가되었으며,수생식물의 높은 생물량은 어류의 높은 풍부도 유지에 크게 기여하였다. 이러한 관점에서 습지를 복원하거나 새롭게 조성할 때 수생식물의 적절한 식재는 어류의 종 다양성에 영향을 줄 것으로 보이며, 어류가 수생태 먹이망 내에서 최상위포식자로서의 역할을 한다는 점을 감안할 때 먹이망의 건강성 유지에도 필수적일 것으로 사료된다. In order to investigate the distribution and species composition of fish in shallow wetlands that might be affected by environmental factors, we investigated the physicochemical parameters, macrophytes biomass, and fish assemblage in 24 shallow wetlands in South Korea from May to June, 2012. In this study, a total of 20 fish species were identified, and Cypinidae were found to be the most dominant species. Physicochemical parameters and macrophyte biomass were different in the survey sites, and macrophytes biomass, in particular, showed a positive relationship with fish abundance in stepwise multiple regression (df=1, F=32.00, P=0.001). According to the result of the cluster analysis between survey sites, the survey sites were divided into three groups in accordance with species composition of fish in relation to macrophytes biomass. In the wetlands of the first group, Lepomis macrochirus which belongs to Centrarchidae was found to be dominant and other fish assemblages were hardly seen. In the second group, unlike the first group, Carassius auratus that belongs to Cypinidae was found to be dominant. In the third group, Lepomis macrochirus was found to be as dominant as the first group but various other fish species appeared. Where there was abundance of the main food sources (i. e. zooplankton) of fish in the survey sites, there were more diverse macrophyte biomass. Consequently, it is proven that macrophytes strongly affect the species composition and abundance of fish, and high biomass of macrophytes support high assemblage of fish. Based on these results, we recommend establishing diverse aquatic macrophytes communities when restoring or creating wetlands to assure high diversity of fish species that use macrophytes as their habitat.