Steam reforming of methanol for ultra-pure H₂ production in a membrane reactor: Techno-economic analysis

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>

Hydrogen production by steam methane reforming in a membrane reactor equipped with a Pd composite membrane deposited on a porous stainless steel

Kim, Chang-Hyun,Han, Jae-Yun,Kim, Sehwa,Lee, Boreum,Lim, Hankwon,Lee, Kwan-Young,Ryi, Shin-Kun Elsevier 2018 International journal of hydrogen energy Vol.43 No.15

<P><B>Abstract</B></P> <P>With the aim of producing hydrogen at low cost and with a high conversion efficiency, steam methane reforming (SMR) was carried out under moderate operating conditions in a Pd-based composite membrane reactor packed with a commercial Ru/Al<SUB>2</SUB>O<SUB>3</SUB> catalyst. A Pd-based composite membrane with a thickness of 4–5 μm was prepared on a tubular stainless steel support (diameter of 12.7 mm, length of 450 mm) using electroless plating (ELP). The Pd-based composite membrane had a hydrogen permeance of 2.4 × 10<SUP>−3</SUP> mol m<SUP>−1</SUP> s<SUP>−1</SUP> Pa<SUP>−0.5</SUP> and an H<SUB>2</SUB>/N<SUB>2</SUB> selectivity of 618 at a temperature of 823 K and a pressure difference of 10.1 kPa. The SMR test was conducted at 823 K with a steam-to-carbon ratio of 3.0 and gas hourly space velocity of 1000 h<SUP>−1</SUP>; increasing the pressure difference resulted in enhanced methane conversion, which reached 82% at a pressure difference of 912 kPa. To propose a guideline for membrane design, a process simulation was conducted for conversion enhancement as a function of pressure difference using Aspen HYSYS<SUP>®</SUP>. A stability test for SMR was conducted for ∼120 h; the methane conversion, hydrogen production rate, and gas composition were monitored. During the SMR test, the carbon monoxide concentration in the total reformed stream was <1%, indicating that a series of water gas shift reactors was not needed in our membrane reactor system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CH<SUB>4</SUB> conversion reached ∼82% at a ΔP = 912 kPa at 823 K in Pd/PSS membrane reformer. </LI> <LI> H<SUB>2</SUB> ∼97.7% was obtained in the permeate stream with CO<SUB>2</SUB> 60% in the retentate stream. </LI> <LI> MSR results in Pd/PSS membrane reactor was well agreement with simulation results. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Process design and techno-economic analysis

Sehwa Kim(김세화),Juhoen Heo(허주헌),Yoon Soo Han(한윤수),Jaryoung Han(한자령),Jinmo Park(박진모),Hyungsik Kim(김형식),Boreum Lee(이보름),Hankwon Lim(임한권) 한국가스학회 2018 한국가스학회 학술대회논문집 Vol.2018 No.11

Increase in serum haptoglobin and apolipoprotein M in patients with obstructive sleep apnoea

KIM, JINKWAN,LEE, SEUNGGWAN,IN, KWANGHO,KIM, JEHYEONG,YOU, SEHWA,KANG, KYUNGHO,SIM, JAEJEONG,LEE, SANGYEUB,YOON, DAEWUI,LEE, JUNGBOK,SHIN, CHOL Blackwell Publishing Ltd 2009 Journal of sleep research Vol.18 No.3

<P>Summary</P><P>Obstructive sleep apnoea (OSA) is a common syndrome, which is associated with a number of medical problems that impact morbidity and mortality. Although the precise mechanisms that underlie these associations are not fully understood, previous studies have suggested that patients with OSA show elevations of several biomarkers that are associated with cardiovascular risk. This study was undertaken to identify serum proteins associated with OSA by using a proteomics technique and to examine changes in identified protein levels after continuous positive airway pressure treatment. The study participants consisted of 40 male patients (aged 40–49 years) with severe OSA and 34 male control subjects matched for age and body mass index. All subjects underwent polysomnography. Using a proteomics approach, we identified nine proteins that were differentially expressed in patients with severe OSA and controls. Three of these nine proteins, haptoglobin, paraoxonase-1 and apolipoprotein M, were quantified by using enzyme-linked immunosorbent assays, kinetic assays and by using Western blotting. Multiple regression analysis showed that haptoglobin and apolipoprotein M levels are independently related to apnoea–hypopnoea index (<I>P</I> < 0.01). A further study is required to determine the nature of associations between these identified proteins and OSA in a large population.</P>

Why Should GUI Designers Create Visual Novelties?

Sehwa Kim 한국디자인학회 2019 디자인학연구 Vol.32 No.2

Assessment of the regional economic potential for methanol steam reforming based on historical data of natural gas price and CO₂ tax credit

Sehwa Kim(김세화),Wonmo Yeon(연원모),Hankwon Lim(임한권) 한국에너지기후변화학회 2018 한국에너지기후변화학회 학술대회 Vol.2018 No.11

Electric Propulsion Naval Ships with Energy Storage Modules through AFE Converters

Kim, So-Yeon,Choe, Sehwa,Ko, Sanggi,Kim, Sungmin,Sul, Seung-Ki The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

This paper proposes a novel electric propulsion system for naval ships, which consists of Active Front End (AFE) converters directly connected to battery Energy Storage Modules (ESMs). Employing the proposed AFE converters with ESMs in the power systems of naval ships can enhance the reliability and quality of the electric power. Furthermore, the fuel-efficiency of the generator can be improved by a higher loading factor of the generator and its prime movers. The proposed AFE configuration does not require an additional dedicated DC/AC converter for the ESMs. Instead of that, the AFE converter itself can control the DC link voltage and the discharging and/or charging of the ESMs. A control scheme to achieve these control objectives is also presented in this paper. The overall power system, including the generators and electrical loads of a naval ship, is implemented by a small scaled Power Hardware-In-the-Loop (PHIL) simulator. Through this experimental setup, the proposed system configuration and the power control strategies are verified. It is shown that the fuel-efficiency and transient dynamics can be improved in the normal and contingency operation modes.

셀프리더십이 역할행동, 조직시민행동 및 혁신행동에 미치는 영향

김세화(Sehwa Kim),이희정(Heejung Lee),양동민(Dongmin Yang),허영호(Youngho Heo),심덕섭(Duksup Shim) 한국인사관리학회 2009 한국인사관리학회 학술대회 발표논문집 Vol.2009 No.3

본 연구는 11개 조직, 213명의 종업원을 대상으로 한 설문조사를 통해 통제위치, 후원적 리더십, 조직후원인식이 셀프리더십에 미치는 영향과 함께 셀프리더십이 역할행동, 조직시민행동, 그리고 혁신행동에 영향을 주는지를 밝히고자 하였다. 또한, 셀프애피커시가 셀프리더십과 역할행동, 조직시민행동, 그리고 혁신행동 간의 관계를 매개하는지를 밝히고자 하였다. 연구결과, 통제위치, 후원적 리더십, 조직 후원인식은 셀프리더십에 유의한 영향을 미치고 있으며, 셀프리더십 또한 역할행동, 조직 시민행동, 혁신행동 모두와 긍정적인 정의 관계를 가지는 것으로 나타났다. 그리고 셀프 애피커시는 셀프리더십과 역할행동 간의 관계를 완전 매개하며, 셀프리더십과 조직시민행동(OCBI), 셀프리더십과 혁신행동 간의 관계를 부분 매개하고 있음을 발견하였다. 연구결과를 바탕으로 연구의 시사점과 한계점 및 향후 연구 과제를 논의하였다. While self-leadership has been acknowledged by its proponents as a core element required in a self-managed work team environment, review of existing studies reveals that empirical studies to examine the influence of individual differences, leadership and organizational characteristics on self-leadership have been limited. In addition, while prior empirical studies examined the relationship between specific self-leadership behaviors and subsequent performance, but a few research examined how the self-leadership behaviors translate into performance. Drawing upon existing theoretical and empirical evidence, this study aims to examine the influence of locus of control, supportive leadership and perception of organizational support(POS) on self-leadership, and to examines the effects of self-leadership on in-role behavior, organizational citizenship behavior(OCB) and innovative behavior. Data were collected from 213 individuals in 11 organization to test theoretical model and its hypotheses. Research finding indicates that locus of control, supportive leadership and POS contribute to the development of subsequent follower self-leadership. Research finding also indicates that self-leadership is positively associated with the ratings of in-role behavior, OCBI, OCBO, and innovative behavior. Further, self-efficacy perceptions were found to mediate the self-leadership/performance relationship, suggesting that self-leadership behaviors may have their initial influence on self-efficacy perception, which subsequently affect performance. Based on these findings, implications of the research findings are discussed, and recommendation for future research are provided.

Increasing the Usability of Open Market Seller Webpages

SoYoung Kim,SeHwa Kim 한국콘텐츠학회 2014 한국콘텐츠학회 ICCC 논문집 Vol.- No.-

다매체 활용 환경교육이 초등학생의 환경친화적 태도에 미치는 영향

김세화(Sehwa Kim),이상원(Sang-Won Lee) 한국환경교육학회 2008 環境 敎育 Vol.21 No.3

The purpose of this study was to investigate the influences of environmental education program through various instructional media on pro-environmental attitudes of forth graders in an elementary school in Seoul. The students were divided into an experimental group and a control group. A questionnaire was used to survey the effects of applying environmental education program through various instructional media. The SPSS 12.0 program was used to analyze the results. The student in the experimental group acquired a higher level of pro-environmental attitudes than the control group did. The environmental education program through various instructional media used in this study were effective especially in dealing with the environmental educational subdomains such as verbal commitment, actual commitment, affect. The major results of this study were as follows. First, environmental education program through various instructional media had a positive effect on the environmental concerns and needs for learning of environmental problems. Second, the group by environmental education program through various instructional media showed the significant difference(p<.001) on the pro-environmental attitudes as it proved those are effect on 3 subdomains of verbal commitment, actual commitment and affect. Third, environmental education program through various instructional media had a positive correlation(from 585 to .680) among the 3 subdomains of verbal commitment, actual commitment and affect. So, students who hold verbal commitment showed good effect on the actual commitment and affect. In conclusion, the environmental education program through various instructional media had a positive effect on pro-environmental attitudes of elementary school students. It is demanded that more intensive research on this study should be done, linking with teaching and learning method, as a follow-up activity.