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Kim, Sehwa,Yun, Su-Won,Lee, Boreum,Heo, Juheon,Kim, Kihyung,Kim, Yong-Tae,Lim, Hankwon Elsevier 2019 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.44 No.4
<P><B>Abstract</B></P> <P>Process simulation and design as well as economic analysis were carried out to evaluate technical and economic feasibility of steam reforming of methanol in a membrane reactor (MR) for ultra-pure H<SUB>2</SUB> production. Using a commercial process simulator, Aspen HYSYS<SUP>®</SUP>, comparative studies were conducted to investigate the effect of operating conditions including the H<SUB>2</SUB> permeance (1 × 10<SUP>−5</SUP> - 6 × 10<SUP>−5</SUP> mol m<SUP>−2</SUP> s<SUP>−1</SUP> Pa<SUP>−1</SUP>), a H<SUB>2</SUB>O sweep gas flow rate (1–20 kmol h<SUP>−1</SUP>), and a reaction temperature (448–493 K) in a conventional packed-bed reactor (PBR) and the MR using a previously reported reaction kinetics. Improved performances such as methanol conversions and H<SUB>2</SUB> yields were observed in the MR compared to the PBR and several design guidelines for the MR were obtained to develop H<SUB>2</SUB> separation membranes with optimal H<SUB>2</SUB> permeance and to select a suitable H<SUB>2</SUB>O sweep gas flow rate. In addition, economic analysis based on itemized cost estimations was conducted for a small-sized H<SUB>2</SUB> fueling station by calculating a unit H<SUB>2</SUB> production cost for both the PBR and the MR reflecting a current economic status in Korea. As a result, a cost saving of about 23% was obtained in the MR (7.24 $ kgH<SUB>2</SUB> <SUP>−1</SUP>) compared to the PBR (9.37 $ kgH<SUB>2</SUB> <SUP>−1</SUP>) confirming the benefit of employing the MR for ultra-pure H<SUB>2</SUB> production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Techno-economic analysis for steam reforming of methanol was conducted. </LI> <LI> Improved methanol conversion and H<SUB>2</SUB> yield were obtained in the MR. </LI> <LI> A cost saving of about 23% in a unit H<SUB>2</SUB> production cost was observed in the MR. </LI> </UL> </P>
Kim, Sanghoon,Kim, Duckhyun,Choi, Hyunbong,Kang, Moon-Sung,Song, Kihyung,Kang, Sang Ook,Ko, Jaejung Royal Society of Chemistry 2008 Chemical communications Vol.2008 No.40
<P>Organic dyes with long alkyl chains have been synthesized and demonstrated to be highly efficient sensitizers for liquid and quasi-solid-state solar cells, giving power conversion efficiencies of 8.31–8.39% and 7.03–7.31% under AM 1.5 G irradiation, respectively.</P> <P>Graphic Abstract</P><P>Organic dyes with long alkyl chains have been synthesized and demonstrated to be highly efficient sensitizers for liquid and quasi-solid-state solar cells, giving power conversion efficiencies of 8.31–8.39% and 7.03–7.31% under AM 1.5 G irradiation, respectively. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b811401c'> </P>
Youngkun Kim,WoongIl Kim,Seungju Baek,Kihyung Lee 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.3
Global warming and finite amount of oil resources have become serious issues. For this reason, the development of eco-friendly vehicles, using biofuel or oher materials has attracted significant attention. In particular, bioethanol has been focused on as an alternative to gasoline because it does not require a full-scale remodeling of a conventional internal combustion engine. However, the differences in the physical characteristics between gasoline and ethanol can lead to different spray characteristics, which can significantly affect the level of combustion. This study aims to identify the physical characteristics of an ethanol-gasoline blended fuel, including its viscosity, density and temperature by measuring the Sauter mean diameter (SMD) and applying a spray visualization. Through these experiments, basic data regarding the fuel characteristics and spray patterns according to the ethanol content required for an optimized combustion of an ethanol-gasoline blended fuel, are provided.
조사 분사 방식을 이용한 HCCI 엔진의 연소 및 배기특성에 관한 실험적 연구
김형민(Hyungmin Kim),류재덕(Jeaduk Ryu),이기형(Kihyung Lee),김병수(Byungsu Kim) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The new concept called as Homogeneous Charge Compression Ignition engines are spotlighted because this concept reduced NOx and smoke simultaneously. To accomplish this combustion, many researchers are studying various methods called the PREDIC, MK, NADl, MULDIC, UNIBUS, HCDC, CAI and PCCI. The purpose of this study was to investigate characteristics of combustion and emission in a common rail direct injection type HCCI engine using a early injection method called the PCCI(Premixed Charge Compression Ignition). From this study, we found that the NOx emissions were dramatically reduced compare to conventional diesel combustion. The smoke emissions also showed a slightly reduction, while CO and HC emissions increased substantially. And the operating condition of HCCI engine limited a low loads.
Tae-Jeong Kim,Jin Seok Hong,Eun Ji Lee,Youngjin Kang*,Jae Jung Lee,Dong-Uk Kim,Eun Me Han,Kihyung Song 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.12
New group 15 organometallic compounds, M(phenanthrenyl)3 (M = P (1), Sb (2), Bi (3)) have been prepared from the reactions of 9-phenanthrenyllithium with MCl3. A reaction of 9-(diphenylphosphino)phenanthrene with 2,6-diisopropylphenyl azide led to the formation of (phenanthrenyl)(Ph)2P=N-(2,6-iPr2C6H3) (4). The crystal structures of 2 and 4 have been determined by single-crystal X-ray diffractions, both of which crystallize with two independent molecules in the asymmetric unit. Compound 2 shows a trigonal-pyramidal geometry around the Sb atom with three phenanthrenyl groups being located in a screw-like fashion with an approximately C3 symmetry. A significant amount of CH--- interaction exists between two independent molecules of 4. The phosphorus center possesses a distorted tetrahedral environment with P-N bond lengths of 1.557(3)Å (P(1)-N) and 1.532(3)Å (P(2)-N), respectively, which are short enough to support a double bond character. One of the most intriguing structural features of 4 is an unusually diminished bond angle of C-N-P, attributable to the hydrogen bonding of N(1)-H(5A) [ca. 2.49] between two adjacent molecules in crystal packing. The compounds 1-3 show purple emission both in solution and as films at room temperature with emission maxima (max) at 349, 366, and 386 nm, respectively, attributable to the ligand-centered * transition in phenanthrene contributed by the lone pair electrons of the Gp 15 elements. Yet the nature of luminescence observed with 4 differs in that it originates from (diisopropylbenzene)-* (phenanthrene) transitions with the p-contribution from the nitrogen atom. The emission maximum of 4 is red-shifted ranging 350-450 nm due to the internal charge transfer from the phenanthrenyl ring to the N-arylamine group as deduced from the ab initio calculations
디젤 엔진의 다단 조기 분사가 엔진 연소 및 배기 특성에 미치는 영향
김재웅(Jaewoong Kim),김영진(Yungjin Kim),박상기(Sangki Park),이기형(Kihyung Lee) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5
Diesel engine technologies have been improved owing to high pressure common rail injection system. Since emission regulation for diesel engine has been enhanced, researchers tried to find a way to decrease NOx and PM such as clean combustion and after treatment. Among these clean combustion, premixed charge compression ignition technology is spotlighted as one of candidates for reducing NOx and PM simultaneously. In order to establish the premixed charge compression ignition, fuel is injected during early compression stroke and it can make enough time for uniform air-fuel mixture formation. Therefore, it is necessary to inject the fuel early timing to make homogeneous mixture in a cylinder. In this paper, early injections were used to get better combustion stability and characteristics of combustion and emissions were investigated with early injection strategies such as various early injection numbers(?) and timings. As a result, smoke was increased a little but it was still low. In addition, THC and fuel consumption were also showed similar levels. However, NOx emission was reduced conspicuously with the use of early injection.