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[PA-0008] Assembly and Analysis of the Complete mitogenome of Silybum marianum
Jeongwoo Lee(Jeongwoo Lee),Yedomon Ange Bovys Zoclanclounon(Yedomon Ange Bovys Zoclanclounon ),Hwajin Jung(Hwajin Jung),Taeho Lee(Taeho Lee),Jeonggu Kim(Jeonggu Kim),Guhwang Park(Guhwang Park),Keunpyo 한국육종학회 2022 한국육종학회 공동학술발표집 Vol.2022 No.-
승용디젤 엔진에서 JP-8 연료 적용 시 다단분사를 이용한 배기저감 방법 연구
이정우(Jeongwoo Lee),주상현(Sanghyun Chu),이정연(Jungyeon Lee),이승현(Seunghyun Lee),이윤우(Yoonwoo Lee),이성문(Sungmoon Lee),최회명(Hoimyung Choi),민경덕(Kyungdoug Min) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5
As a statement of EURO-6 regulation, NOx emission should be reduced as a half of current standard from September, 2014. For the reduction of NOx emission, EGR is the most effective method due to thermal and diluted effects. However, since there is a trade-off relation between NOx and PM emissions, using heavy EGR rate stimulates the increment of PM emission. For this reason, many of Diesel engine have equipped DPF to eliminate PM emission, but it brings the deterioration of fuel consumption. JP-8 could be a good approach to reduce PM emission from Diesel engine. Since cetane number of JP-8 is lower than that of Diesel, ignition delay becomes prolonged. Also, premixed condition between air and fuels could be improved, because distillation temperature of JP-8 is lower than that of Diesel. These two characteristics effect on the reduction of PM emission. However, in previous researches, phenomenon of NOx increment was observed by JP-8 fueled combustion because of prolonged ignition delay. Thus, in this research, reduction of NOx and PM emissions simultaneously is studied by using multiple injection strategy constructing with pilot injections. The result shows low PM emission could be obtained while there is no penalties on NOx emission.
Lee, Jeongwoo,Lee, Sunyoup,Lee, Seokhwan Elsevier 2018 Fuel Vol.220 No.-
<P><B>Abstract</B></P> <P>The diesel compression ignition (CI) engine has higher durability and thermal efficiency than the gasoline spark ignition (SI) engine. However, the high levels of nitrogen oxides (NOx) and particulate matter (PM) emissions are major problems of diesel engines due to the auto-ignition of heterogeneous mixtures. The dual-fuel combustion concept could be solution to environmental concerns. Dual-fuel combustion can be implemented by substituting some of the diesel fuel with high-volatility fuels, such as gasoline and natural gas. The premixed mixture condition can be improved to diminish localized rich and stoichiometric regions. Notably, ethanol has greater potential to reduce PM emissions because it is highly volatile and readily oxidized.</P> <P>For these reasons, in this research, the effects of varying the ethanol substitution ratio on engine performance and emissions under the dual-fuel combustion condition were experimentally investigated under various load conditions. The test engine was a heavy-duty single-cylinder diesel engine with two direct injectors. Engine speed was fixed at 1000 rpm and the load condition was varied for an indicated mean effective pressure (IMEP) ranging from 0.2 to 0.8 MPa. The ratio of ethanol to the total input energy was controlled from zero to nearly 50% of the input energy. The NOx and PM emissions decreased with increasing ethanol substitution and the mean size of the PM emissions decreased. For the mid-load condition (IMEP 0.6 MPa), the substitution was increased to 63%, but for low and high loads, higher ethanol fractions could not be used because of insufficient ignition energy at low loads and sharp increment of the in-cylinder pressure under high loads.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dual-fuel combustion with two direct injectors was investigated. </LI> <LI> The effects of various ethanol fractions and diesel injection timings were verified. </LI> <LI> The characteristics of energy fractions were analyzed. </LI> <LI> The characteristics of combustion duration were analyzed. </LI> </UL> </P>
Lee Jeongwoo,Lee Minyong,Kim Donggun,Shin Yongbeom,Lee Jae W. 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.12
This study aimed to design energy-efficient systems for reactive distillation to simultaneously produce methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) from mixed feeds of methanol and ethanol. In this work, two new designs are proposed. One is the individual production of each ether, involving two reactive distillation columns after feed alcohol separation, while the other for the co-production of both ethers in a single reactive distillation column without the alcohol separation. Rigorous simulations of the two proposed systems were conducted with varying ratios of the two alcohols in actual process streams. When the methanol feeding was dominant, the co-production system exhibited better performance than the individual ether production system. This was due to the lower temperatures inside the alcohol separation column, resulting in a lower relative volatility of methanol and increasing the heat duty in the alcohol separation column. However, when the amount of ethanol was higher than that of methanol, the individual production system outperformed the co-production system. This was attributed to the unfavorable reaction equilibrium of ETBE production, leading to a high internal flowrate in the co-production reactive distillation column. The external heat integration of each design can bring further reduction in energy consumption and CO2 emissions, but the results follow the same dependence on the feed alcohol ratio.
높은 배기재순환 율 조건에서 하드웨어 조합에 따른 디젤 연소 및 배기 특성 비교
이정우(Jeongwoo Lee),최승목(Seungmok Choi),신승협(Seunghyup Shin),이효원(Hyowon Lee),이승현(Seunghyun Lee),최회명(Hoimyung Choi),민경덕(Kyungdoug Min) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
High EGR rate promises to extremely low NOx emission level to meet the regulations of vehicle emissions. Especially, in EURO-6 regulation from 2014, NOx emission must be reduced 55.6 % more than current emission regulation, EURO-5. Therefore, to suppress NOx emission, using high EGR rate becomes more important. However, if high EGR rate is used, CO, THC and PM emissions are increased drastically comparing to those of moderate EGR rate condition. It is a reason that low oxygen concentration due to high EGR rate makes combustion efficiency lower and oxidization of PM worse. Therefore, in this research, two different nozzles and piston bowl shapes are employed to stabilize the combustion with high EGR rate and reduce CO, THC and PM emissions. The result shows that the combination of two stage piston with lower depth bowl and double row nozzle is best fit to reduce CO, THC and PM emissions holding extremely low NOx level.
높은 배기재순환 율의 디젤 연소에서 부하 조건에 따른 Close post injection 전략이 배기 저감에 미치는 영향
이정우(Jeongwoo Lee),최승목(Seungmok Choi),이준용(Junyong Lee),이승현(Seunghyun Lee),최회명(Hoimyung Choi),민경덕(Kyungdoug Min) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
EGR method has been widely used to suppress NOx emission by thermal and dilution effects. However, high EGR rate brings higher PM level and lower combustion efficiency. Thus, close post injection strategy is introduced to reduce PM emission and improve combustion efficiency, since it makes ignition delay prolonged and fuel distribution well. Close post injection strategy means the split injection with main and post injections which have the shortest dwell time between them. So in this research, the load conditions were varied to find out the effect of load condition on close post injection strategy. It gives more comprehensive results to evaluate the characteristics of the close post injection strategy. The results show that the effect of close post injection strategy on emission reduction becomes greater as LTR region becomes prolonged by higher load condition.