Turquoise Hydrogen Production from Methane Using Molten Catalysts

Dohyung Kang(강도형),Dasol Bae(배다솔),Eun Hee Ko(고은희),Min Seok Kim(김민석),Jae Min Jang(장재민),No-Kuk Park(박노국),Minkyu Kim(김민규) 한국에너지기후변화학회 2022 한국에너지기후변화학회 학술대회 Vol.2022 No.10

Methane Decomposition for Hydrogen and Separable Carbon Production in Molten Transition Metal Halides

Dohyung Kang,Jin Ho Boo,Eun Hee Ko,H. Jung,Byung Chan Kwon,No-Kuk Park 한국신재생에너지학회 2021 AFORE Vol.2021 No.10

Enhanced catalytic activity of methane dry reforming by the confinement of Ni nanoparticles into mesoporous silica

Kang, Dohyung,Lim, Hyun Suk,Lee, Jae W. Pergamon Press 2017 International journal of hydrogen energy Vol.42 No.16

<P><B>Abstract</B></P> <P>Nickel nanoparticles were immobilized in mesoporous silica by a polyethyleneimine (PEI)-aided route and their catalytic performance was evaluated in dry reforming of methane. NH<SUB>2</SUB> terminal groups of PEI strongly interacted with surface silanol groups of mesoporous silica and then, Ni-chelating PEIs were highly dispersed inside its ordered channel. The steric hindrance of PEI with a long hydrocarbon chain also restricted the aggregation of Ni-PEI complexes anchored in the porous framework. The catalysts prepared by the PEI-aided route showed the stable activity at 750 °C for 40 h because Ni particles were confined inside the pore and therefore, cannot be sintered more than the pore diameter of their parent support. The carbon deposit is much smaller in the catalyst prepared by the PEI-aided route than the reference catalyst synthesized via a traditional impregnation method, suggesting that the sintering of Ni particles is a main contribution to the generation of graphitic carbon.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni nanoparticles were confined in a mesoporous silica through PEI grafting. </LI> <LI> Interaction between PEI NH<SUB>2</SUB> and silica silanol groups caused an even dispersion of Ni. </LI> <LI> PEI steric hindrance prevented the aggregation of Ni nanoparticles. </LI> <LI> Pore-expanded mesoporous silica facilitated the incorporation of Ni nanoparticles. </LI> <LI> Carbon deposits were greatly reduced due to the pore confinement of Ni nanoparticles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Chemical looping partial oxidation of methane with CO₂ utilization on the ceria-enhanced mesoporous Fe₂O₃ oxygen carrier

Kang, Dohyung,Lee, Minbeom,Lim, Hyun Suk,Lee, Jae W. Elsevier Ltd 2018 Fuel Vol.215 No.-

<P><B>Abstract</B></P> <P>The high-purity syngas production with a molar ratio of H<SUB>2</SUB> to CO equal to 2 was achieved through a chemical looping process with a CH<SUB>4</SUB>-CO<SUB>2</SUB> feed mixture on a ceria-enhanced mesoporous Fe<SUB>2</SUB>O<SUB>3</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB> oxygen carrier. The presence of CO<SUB>2</SUB> in the mixture feed enables the H<SUB>2</SUB>/CO ratio to be maintained as 2 desirable for the syngas-to-liquid hydrocarbon process by suppressing the methane decomposition even when the amount of reducible oxygen carrier was sufficiently small. By incorporating a small amount of CeO<SUB>2</SUB> (molar Ce/Fe ratio = 0.15) to the iron oxide mesoporous oxygen carrier by the sol-gel method, the syngas selectivity also increased although the amount of reducible oxygen was large enough to cause the total combustion. Due to the co-feeding of CO<SUB>2</SUB> with CH<SUB>4</SUB> and the textural property of the ceria-enhanced Fe<SUB>2</SUB>O<SUB>3</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB> mesoporous oxygen carrier, the enhanced redox activity for the chemical looping process was demonstrated under the CO<SUB>2</SUB>/CH<SUB>4</SUB> feed ratio of 0.28 with the redox performance of CH<SUB>4</SUB> conversion = 93.11%, CO selectivity = 93.23%, average carbon deposit = 0.048 mol<SUB>C</SUB>/mol<SUB>syngas</SUB>, and average H<SUB>2</SUB>/CO ratio = 2.04. The fluctuation of the H<SUB>2</SUB>/CO ratio with the reaction time was minimized by adjusting the real-time CO<SUB>2</SUB>/CH<SUB>4</SUB> feed ratio and then, the consistent syngas production was realized even in the fixed bed chemical looping process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ceria-induced mesoporous Fe<SUB>2</SUB>O<SUB>3</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB> (Ce/Fe = 0.15) showed the superior redox activity. </LI> <LI> The <I>meso</I>-porosity was derived from the merge of ceria into the Al<SUB>2</SUB>O<SUB>3</SUB> matrix. </LI> <LI> CO<SUB>2</SUB> was utilized as a co-feed with CH<SUB>4</SUB> in chemical looping process. </LI> <LI> Fluctuation of produced H<SUB>2</SUB>/CO ratio was minimized by adjusting CO<SUB>2</SUB>/CH<SUB>4</SUB> feed ratio. </LI> <LI> High-purity syngas with H<SUB>2</SUB>/CO ratio of 2 was produced via chemical looping process. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Syngas production on a Ni-enhanced Fe₂O₃/Al₂O₃ oxygen carrier via chemical looping partial oxidation with dry reforming of methane

Kang, Dohyung,Lim, Hyun Suk,Lee, Minbeom,Lee, Jae W. Elsevier 2018 APPLIED ENERGY Vol.211 No.-

<P><B>Abstract</B></P> <P>A novel chemical looping process was introduced by combining partial oxidation and dry reforming of methane on a cost-effective iron-based oxygen carrier to produce high-purity syngas with a H<SUB>2</SUB>/CO ratio of 2. The rationale for the proposed chemical looping process was substantiated with the thermodynamic data, which showed increased syngas purity and an H<SUB>2</SUB>/CO ratio close to 2 by introducing the CH<SUB>4</SUB>-CO<SUB>2</SUB> mixture feed. Compared with the general chemical looping process, the calculated carbon deposition with the CO<SUB>2</SUB> emission of the proposed process was dramatically decreased by using CO<SUB>2</SUB> as a co-feed with CH<SUB>4</SUB>. Due to the exothermic heat from the oxidation reaction of the oxygen carrier, the net heat duty of the novel chemical looping process was much lower than that of the dry reforming process. To validate the thermodynamic results, a Ni entrapped Fe<SUB>2</SUB>O<SUB>3</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB> oxygen carrier was synthesized by increasing the metal-support interaction through a sol-gel route. It is striking that the formation of Ni aluminate phase in the Ni-reinforced oxygen carrier facilitated dry reforming with partial oxidation while suppressing methane decomposition. By supplying a nonstoichiometric CH<SUB>4</SUB>-CO<SUB>2</SUB> mixture feed (CO<SUB>2</SUB>/CH<SUB>4</SUB> ratio = 0.38) to the 1 wt% Ni-entrapped Fe<SUB>2</SUB>O<SUB>3</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB> oxygen carrier at 900 °C, an H<SUB>2</SUB>/CO ratio of 2.09 and high CO selectivity of 96.76% were achieved with minimized carbon deposition. These results were close to the calculated equilibrium value while a Ni-impregnated Fe<SUB>2</SUB>O<SUB>3</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB> oxygen carrier showed an increased H<SUB>2</SUB>/CO ratio of 2.36 with severe carbon deposition by the promoted methane decomposition. In addition, the Ni-reinforced oxygen carrier also showed stable redox activity during successive reduction and oxidation cycles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CLPD was derived by merging dry reforming into chemical looping partial oxidation. </LI> <LI> Results of CLPD were calculated using the ASPEN Plus simulator. </LI> <LI> Syngas with a H<SUB>2</SUB>/CO ratio of 2 was produced through the CLPD process. </LI> <LI> Ni-enhanced Fe<SUB>2</SUB>O<SUB>3</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB> showed the enhanced CLPD activity without rare earth metals. </LI> <LI> Stabilized Ni in Al<SUB>2</SUB>O<SUB>3</SUB> promoted dry reforming with suppressed carbon deposition. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

융용 촉매 상에서 메탄 분해를 통한 수소 및 분리 가능한 탄소 생산

강도형(Dohyung Kang) 한국에너지기후변화학회 2019 한국에너지기후변화학회 학술대회 Vol.2019 No.11

Contact Resistivity Properties of Metal Paste on the Rear Side in p-TOPCon Solar Cells

Dohyung Kim(김도형),Yong-Jin Kim(김용진),June Sung Park(박준성),Kyu Hyeon Im(임규현),Mun Se Kim(김문세),Sang Hee Lee(이상희),Yun Ae Cho(조윤애),Kyung Taek Jeong(정경택),Sungeun Park(박성은),Min Gu Kang(강민구),Hee-eun Song(송희은) 한국태양에너지학회 2022 한국태양에너지학회 학술대회논문집 Vol.2022 No.10

Biomechanical Characteristics of Three Baseplate Rotational Arrangement Techniques in Total Knee Arthroplasty

Kang, KwanSu,Jang, Young Woong,Yoo, Oui Sik,Jung, Dukyoung,Lee, Sung-Jae,Lee, Myung Chul,Lim, Dohyung Hindawi 2018 BioMed research international Vol.2018 No.-

<P><B>Introduction</B></P><P> Several ongoing studies aim to improve the survival rate following total knee arthroplasty (TKA), which is an effective orthopedic surgical approach for patients with severely painful knee joint diseases. Among the studied strategies, baseplate rotational arrangement techniques for TKA components have been suggested but have been the subject of only simple reliability evaluations. Therefore, this study sought to evaluate comparatively three different baseplate rotational arrangement techniques that are commonly used in a clinical context.</P><P><B> Materials and Methods</B></P><P> Three-dimensional (3D) finite element (FE) models of the proximal tibia with TKA were developed and analyzed considering three baseplate rotational arrangement techniques (anterior cortex line, tibial tuberosity one-third line, and tibial tuberosity end line) for six activities of daily life (ADLs) among patients undergoing TKA. Mechanical tests based on the ASTM F1800 standard to validate the FE models were then performed using a universal testing machine. To evaluate differences in biomechanical characteristics according to baseplate rotational arrangement technique, the strain and peak von Mises stresses (PVMSs) were assessed.</P><P><B> Results</B></P><P> The accuracy of the FE models used in this study was high (94.7 ± 5.6%). For the tibial tuberosity one-third line rotational arrangement technique, strains ≤ 50 <I>µ</I>strain (the critical bone damage strain, which may affect bone remodeling) accounted for approximately 2.2%–11.3% and PVMSs within the bone cement ranged from 19.4 to 29.2 MPa, in ADLs with high loading conditions. For the tibial tuberosity end line rotational arrangement, strains ≤ 50 <I>µ</I>strain accounted for approximately 2.3%–13.3% and PVMSs within the bone cement ranged from 13.5 to 26.7 MPa. For anterior cortex line rotational arrangement techniques, strains ≤50 <I>µ</I>strain accounted for approximately 10.6%–16.6% and PVMSs within the bone cement ranged from 11.6 to 21.7 MPa.</P><P><B> Conclusion</B></P><P> The results show that the most recently developed frontal cortex line rotational alignment technique is the same or better than the other two rotational alignment techniques in terms of biomechanics. This finding can be, however, dependent on the contact characteristics between the baseplate and the proximal tibia. That is, it is indicated that the optimum baseplate rotational arrangement technique in terms of reducing the incidence of TKA mechanical failure can be achieved by adjusting the characteristics of contact between the baseplate and the proximal tibia.</P>

A Study on CFD Data Compression Using Hybrid Supercompact Wavelets

Hyungmin Kang,Dongho Lee,Dohyung Lee 대한기계학회 2003 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.17 No.11

A hybrid method with supercompact multiwavelets is suggested as an efficient and practical method to compress CFD dataset. Supercompact multiwavelets provide various advantages such as compact support and orthogonality in CFD data compression. The compactness is a crucial condition for approximated representation of CFD data to avoid unnecessary interaction bet­ween remotely spaced data across various singularities such as shock and vortices. But the supercompact multi wavelet method has to fit the CFD grid size to a product of integer and power of two. m×2^n. To resolve this problem, the hybrid method with combination of 3.2 and 1 dimensional version of wavelets is studied. With the hybrid method, any arbitrary size can be handled without any shrinkage or expansion of the original problem. The presented method allows high data compression ratio for fluid simulation data. Several numerical tests substantiate large data compression ratios for now field simulation successfully.

Rule Database를 활용한 가망수요 정보 규칙 관리

김도형(Dohyung Kim),강명철(Myungchul Kang) 한국정보과학회 2003 한국정보과학회 학술발표논문집 Vol.30 No.1A

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