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냉시동 조건에서 디젤연료의 온도에 따른 유동 및 분무특성 변화
신주곤 ( Jugon Shin ),박현욱 ( Hyunwook Park ),배충식 ( Choongsik Bae ) 한국액체미립화학회 2016 한국액체미립화학회 학술강연회 논문집 Vol.2016 No.-
With the increasing use of diesel engines, emission regulations continuously become stringent such as particulate matter and nitrogen oxides as well as carbon dioxide. Issues related to the emission problem in diesel engines are represented seriously under cold-start conditions. Flow and spray characteristics of diesel fuel could be also problems under cold-start conditions, because fuel properties such as viscosity and density are changed by fuel temperature, especially at low ambient conditions. In this research, the effect of diesel fuel temperature on the flow and spray behavior under cold-start conditions was studied. The flow and spray characteristics of diesel fuel were investigated for injection rate using Bosch tube method and liquid-phase fuel penetration using Mie scattering in a constant volume combustion chamber, respectively. The injection quantity decreased at the same injection duration because of the increase fuel viscosity, as the fuel temperature deceased from 293 K to 253 K. In addition, the liquid-phase fuel penetration was longer by attenuating fuel evaporation due to low fuel and ambient temperature, and the spray angle was smaller especially in the initial stage of diesel fuel injection as well. The decrease of evaporation of injected fuel inside the chamber made the liquid-phase fuel penetration last longer. These results mean that the low fuel and ambient temperature have a negative effect on air-fuel mixing process.
신재생발전 확대적용을 위한 ESS와 천연가스발전기의 경제성 평가
주용진,신주곤,서동균,박세익,JOO, YONGJIN,SHIN, JUGON,SEO, DONGKYUN,PARK, SEIK 한국수소및신에너지학회 2018 한국수소 및 신에너지학회논문집 Vol.29 No.4
This paper considers the alternative way to mitigate cost for REC instead of Photovoltaic (PV) panels with Energy Storage System (ESS). This study starts from an economic analysis of a 1 megawatt PV system without ESS. Several assumptions have been applied in consideration of the current domestic situation. Based on this result, the economic efficiency of PV with ESS improved. However, the reliance on government subsidies was very high. The alternative way to cover the fluctuation power from renewable energy was reviewed with economical and technical way. In case the natural gas engine applied to PV, the IRR and Levelized Cost of Electricity (LCOE) can be improved without ESS. And if small amount of additional REC, the IRR can be improved up to investment level.
SNG 생산용 공기분리공정의 공기 재 압축비에 따른 민감도 분석
김미영,주용진,서동균,신주곤,Kim, Mi-yeong,Joo, Yong-Jin,Seo, Dong Kyun,Shin, Jugon 한국전력공사 2019 KEPCO Journal on electric power and energy Vol.5 No.3
심랭식 공기분리공정은 공기를 액화시켜 질소와 산소, 아르곤 등 다양한 산업가스를 생산하며, 가스생산조건(순도, 종류)에 따라 공정 또한 달라진다. 그 중 SNG 플랜트 공급용 공기분리공정은 99.5% 이상의 초고순도 산소 생산을 요구하기 때문에 공정의 효율이 타 공기분리공정에 비해 떨어지며, 공정효율을 낮추는 요인에는 공기압축에 의한 소모동력이 대표적이다. 본 연구에서는 SNG 플랜트에 적용하는 공기분리공정의 에너지 효율 향상을 위하여 소모동력과 관련된 공기 압축 설비의 민감도 분석을 수행하였다. 민감도 분석을 위해 ASPEN PLUS를 이용해 공기분리공정을 모사하였다. 모사 결과, 99.5% 이상의 산소 18.21 kg/s를 생산하였으며, 33.26 MW의 동력이 소모되었다. 모사된 공정 중 공기압축설비는 주 압축기 1대와 2대의 재 압축기가 있으며, 2대의 재압축기에서의 공기압축비 변화에 따른 고압질소, 저압산소, 저압질소의 유량과 순도에 대한 영향과 공정 내 소모동력 변화에 대해 분석하였다. 분석 결과, 99.5% 산소, 99% 질소(고압), 90% 질소(저압)를 생산하기 위한 최적의 운전조건은 재압축비가 각각 0.48, 0.50가 되었으며, 재압축비 조정 후 $0.507kWh/O_2kg$에서 $0.473kWh/O_2kg$으로 소모동력도 약 7%가량 줄었음을 확인하였다. Cryogenic air separation unit produces various gases such as $N_2$, $O_2$, and Ar by liquefying air. The process also varies with diverse production conditions. The one for SNG production among them has lower efficiency compared to other air separation unit because it requires ultrapure $O_2$ with purity not lower than 99.5%. Among factors that reduce the efficiency of air separation unit, power consumption due to compress air and heat duty of double column were representatives. In this study, simulation of the air separation unit for SNG production was carry out by using ASEPN PLUS. In the results of the simulation, 18.21 kg/s of at least 99.5% pure $O_2$ was produced and 33.26 MW of power was consumed. To improve the energy efficiency of air separation unit for SNG production, the sensitivity analysis for power consumption, purities and flow rate of $N_2$, $O_2$ production in the air separation unit was performed by change of air boosting ratios. The simulated model has three types of air with different pressure levels and two air boosting ratio. The air boosting ratio means flow rate ratio of air by recompressing in the process. As increasing the first air boosting ratio, $N_2$ flow rate which has purity of 99.9 mol% over increase and $O_2$ flow rate and purity decrease. As increasing the second air boosting ratio, $N_2$ flow rate which has purity of 99.9 mol% over decreases and $O_2$ flow rate increases but the purity of $O_2$ decreases. In addition, power consumption of compressing to increase in the two cases but results of heat duty in double column were different. The heat duty in double column decreases as increasing the first air boosting ratio but increases as increasing the second air boosting ratio. According to the results of the sensitivity analysis, the optimum air boosting ratios were 0.48 and 0.50 respectively and after adjusting the air boosting ratios, power consumption decreased by approximately 7% from $0.51kWh/O_2kg$ to $0.47kWh/O_2kg$.
상용급 가스터빈에서 셰일가스 파일럿비 영향에 관한 수치해석적 연구
서동균,주용진,박세익,김미영,신주곤,Seo, Dong Kyun,Joo, Yong-Jin,Park, Seik,Kim, Mi-yoeng,Shin, Jugon 한국전력공사 2019 KEPCO Journal on electric power and energy Vol.5 No.3
논문에서는 상용급 가스터빈을 대상으로 해서 셰일가스를 연료로 공급할 때 유동 및 연소특성을 3-D 수치해석적 방법으로 구하였다. 이 때, Standard k-e 난류모델, 2단 메탄산화반응, Finite rate/Eddy dissipation 반응모델, DTRM 복사모델이 사용되었고, 기준조건(도시가스, PR 0.07)에서 출구 측에서 형성되는 온도는 이전 문헌 값과 비슷한 값을 보였다. 위 모델을 바탕으로 해서 연료조건으로 기존의 도시가스 외에 세 가지 셰일가스 조건(도시가스 대비 열량기준 80%, 90%, 105%)을 선정하였고, 각 연료조건에 대하여 세 가지 연료분사조건(PR=0.7, 0.9, 0.11)에 대한 해석을 수행하였다. 해석결과, 모든 셰일가스 연료공급 조건에 대하여 도시가스 대비 온도 혹은 NOx 측면에서 연소안정화를 만족하였다. 또한 모든 조건에 대해서 PR이 증가할수록 출구측 평균온도는 일정했지만 NOx량은 증가하였다. 이는 파일럿비가 증가할수록 상대적으로 확산연소가 증가했기 때문이다. In this work, the flow and combustion characteristics using a 3-D numerical simulation was evaluated for a shale gas fueled combustor in a commercial class gas turbine. The Standard k-e turbulence model, 2 step methane oxidation mechanism, Finite rate/Eddy dissipation reaction model, DTRM radiation model were employed and validated well at the baseline condition (Natural Gas, Pilot Ratio 0.2). Based on the validated models, the combustion characteristics of shale gas was evaluated for three pilot ratios cases. It was found that NOx concentrations for all shale gas cases were less than the that for city gas, which imply that, at the selected PRs, the condition for combustion stability is satisfied. In addition, for higher PR, whereas the average temperatures at the exit are the same, the NOx increases. It means that diffusion combustion portion increases due to the higher PR.