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The present condition and outlook for hydrogen-natural gas blending technology
채민주,김주현,Bryan Moon,박시몬,이영수 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.2
Korea’s economy should develop a safe and cost-effective hydrogen transport system to realize the hydrogen economy. Among the methods of hydrogen transport, pipelines are the only feasible means of achieving cost-effective and safe transport over longer distances. This technical report proposes a method that would allow for using existing natural gas pipelines to transport mixed gas (hydrogen-natural gas). The properties of the mixed gas, the durability of the pipeline caused by hydrogen embrittlement, and gas loss from leakage are reviewed according to the hydrogen ratio. In addition, several separation methods of mixed gas are introduced. From the survey of international research or pilot projects, if hydrogen is blended with a concentration less than 20%, that does not significantly affect gas quality, safety, risk, materials, and network capacity. This study also suggests the suitable hydrogen supply methods for domestic use.
WS₂ Hollow Sphere Doped by Platinum for High Efficient Hydrogen Evolution Reaction
Minju Chae(채민주),Sujung Suh(서수정),Hanyoung Jung(정한영) 한국신재생에너지학회 2021 한국신재생에너지학회 학술대회논문집 Vol.2021 No.7
Hydrogen is considered an excellent replacement fuel for the efficient and environmentally friendly production of energy. Transition metal dichalcogenides (TMDs) have unique catalytic properties and are earth-abundant, which would allow the production of hydrogen in a facile and low-cost manner. WS<SUB>2</SUB> is a stable and highly active catalyst for the hydrogen evolution reaction (HER). Hollow sphere WS<SUB>2</SUB> nanosheets were synthesized by one-step hydrothermal synthesis, and the prepared WS<SUB>2</SUB> was doped with a platinum chloride solution to enhance HER performance. The diameters of the WS<SUB>2</SUB> hollow spheres were in the range for 400 nm to 2 ㎛, and exhibited an overpotential of 210 mV. The Pt-doped WS<SUB>2</SUB> exhibited an overpotential of 73 mV, which was lower than that of WS<SUB>2</SUB> hollow sphere. Therefore, Pt-doped WS<SUB>2</SUB> is an efficient catalyst for hydrogen evolution reaction. XRD was performed to confirm the crystal structures of the prepared materials. The morphology and composition of the materials were analyzed by SEM and EDS. Raman spectroscopy and TEM were performed to determine the structures and sizes of the materials. The chemical composition was confirmed by XPS.
신장호(Jang-Ho Shin),채민주(Min Joo Chae),한정아(Jung-Ah Han) 한국식품과학회 2021 한국식품과학회지 Vol.53 No.3
유청 분말의 밀가루 대체가 브라우니의 품질특성에 미치는 영향을 알아보기 위해 밀가루의 0-40%를 유청 분말로 대체하여 브라우니를 제조하고 그 특성을 평가하였다. 먼저 외관에서 20% 첨가군까지는 대조군과 차이가 없었으나 30% 첨가군부터 표면의 붕괴현상이 관찰되었다. 브라우니의 굽기손실률은 유청 분말을 대체할수록 유의적으로 감소하였고(p<0.05), 구운 후 무게는 증가하였으나(p<0.05), 부피는 10% 대체군을 제외하면 감소하는 경향을 나타내었다(P<0.05). 이에 비용적은 대조군이 1.66 mL/g이었으나 첨가량에 따라 40% 대체군이 1.33 mL/g까지 감소하여 유의적인 차이를 보였으며(p<0.05), 10% 대체군은 1.73 mL/g으로 가장 높은 결과를 보였다(p<0.05). 수분함량은 11.87-13.62%의 범위로 유청 분말의 대체량이 증가할수록 증가하였으며(p<0.05), pH는 대조군이 7.78로 가장 높고, 유청분말의 첨가량이 증가할수록 감소하는 경향을 나타내었다(p<0.05). 색도 측정에서 껍질의 명도는 유청 분말을 첨가할수록 낮아졌으나, 적색도와 황색도는 30% 대체군까지는 증가하다가 40% 대체군은 감소하여 대조군보다 낮은 결과를 보였다(p<0.05). 속질의 명도와 적색도, 황색도는 첨가량에 따라 감소하는 경향을 보였다(p<0.05). 브라우니의 경도와 응집성은 대조군과 10% 대체군간에는 유의적인 차이가 없었으나(p<0.05), 첨가량이 증가할수록 유의적으로 감소하였고(p<0.05), 점착성은 30% 첨가군부터 크게 증가하였으나(p<0.05), 탄력성은 대조군과 대체군간 유의적인 차이가 없었다(p<0.05). 씹힘성은 유청 분말을 첨가할수록 유의적으로 낮아지는 결과를 보였다(p<0.05). DPPH 라디칼 소거능은 대조군이 35.28%로 가장 낮았으며, 유청첨가량이 증가함에 따라 유의적으로 증가하여 40% 대체군이 51.47%로 가장 높은 것으로 확인되었다(p<0.05). 기호도 검사 결과 외관, 향, 고소함은 대조군과 대체군 간에 유의적인 차이를 보이지 않았으며, 20-30% 대체군이 질감, 맛, 전반적인 기호도에서 가장 높은 선호도를 보였다. 이상의 결과로 유청 분말의 첨가가 브라우니의 항산화 특성을 향상시키면서 물성을 개선하는 것을 확인할 수 있었으며, 외관의 유지와 선호도를 고려하면 밀가루 함량의 20% 수준에서 대체하는 것이 바람직할 것으로 보인다. Brownies containing whey powder (WP) with different levels of substitutions for wheat flour (0, 10, 20, 30, and 40% substitution for WP 0, WP 10, WP 20, WP 30, and WP 40, respectively) were prepared, and their properties were compared. Regarding appearance, the collapse of the sample surface noticeably started from WP 30. The moisture content was higher in samples containing WP than in the control (WP 0), and the weight of the brownie increased with WP content. As the WP amount increased, both the total and specific volumes of the brownies decreased. Regarding texture, a higher amount of WP resulted in a decrease in hardness, whereas adhesiveness increased significantly. The antioxidant activity also increased with increasing WP amount (from 35.28 to 51.47%). Regarding sensory characteristics, 20 or 30% WP in brownies increased mouth-feel properties, taste, and overall preference. Based on the above results, WP could improve the quality of brownies, and a substitution level of 20% could be the most appropriate.
Han young Jung(정한영),Min ju Chae(채민주),Su Jung Suh(서수정) 한국신재생에너지학회 2021 한국신재생에너지학회 학술대회논문집 Vol.2021 No.7
Recently, transition metal dichalcogenides (TMDs), such as MoS<SUB>2</SUB>, have been considered for application in hydrogen evolution catalysis. However, there is a limit to use as a single MoS<SUB>2</SUB> material due to a low charge transfer rate. In this paper, a MoS<SUB>2</SUB>-Pd-Pt catalyst was fabricated on carbon paper in a simple two-step synthesis method. MoS<SUB>2</SUB> and MoS<SUB>2</SUB>-Pd was synthesized via a simple hydrothermal method, and a small amount of Pt was electrodeposited on the prepared sample using a three-electrode system. The nanostructure of MoS<SUB>2</SUB>-Pd has more defects than the structure of MoS<SUB>2</SUB> and the exposure of active sites is high, which is advantageous for the Pt deposition process. In the Pt electrodeposition process, MoS<SUB>2</SUB>-Pd showed higher deposition efficiency and stability than MoS<SUB>2</SUB> in acidic medium. Although a very small amount of Pt was deposited, the hydrogen evolution reaction (HER) properties of MoS<SUB>2</SUB>-Pd-Pt were significantly improved compared to MoS<SUB>2</SUB>-Pd. Moreover, MoS<SUB>2</SUB>-Pd-Pt exhibited excellent catalytic activity with a lower overpotential (-64 mV at 10 mA/cm2) compared to MoS<SUB>2</SUB> (-253 mV) and MoS<SUB>2</SUB>-Pd (-204 mV), thereby proving it a promising electrocatalyst for the HER as an alternative to Pt.