• 한국수소및신에너지학회논문집
• /
• 제30권4호
• /
• pp.303-311
• /
• 2019

Reversible solid oxide fuel cell (RSOFC) has become a prospective device for energy storage and hydrogen production. Many studies have been conducted around the world focusing on system efficiency improvement and realization. The system should have not only high efficiency but also a certain level of simplicity for stable operation. External waste steam utilization was proved to remarkably increase the efficiency at solid oxide electrolysis system. In this study, RSOFC system coupled with waste steam was proposed and optimized in term of simplicity and efficiency. Ejector for fuel recirculation is selected due to its simple design and high stability. Three system configurations using ejector for fuel recirculation were investigated for performance of design condition. In parametric study, the system efficiencies at different current density were analyzed. The system configurations were simulated using validated lumped model in EBSILON(R) program. The system components, balance of plants, were designed to work in both electrolysis and fuel cell modes, and their off-design characteristics were taken into account. The base case calculation shows that, the system with suction pump results in slightly lower efficiency but stack can be operated more stable with same inlet pressure of fuel and air electrode.

• 한국수소및신에너지학회논문집
• /
• 제34권3호
• /
• pp.256-266
• /
• 2023

Hydrogen production can be classified based on the energy source, primary reactor type, and whether or not it emits carbon dioxide. Utilizing color representation proves to be an effective means of expressing these distinctive characteristics. Among the various clean hydrogen production techniques, there has been a growing interest in turquoise hydrogen production, which involves the decomposition of methane or other fossil fuels. This method offers advantages in terms of large-scale production and cost reduction through the sale of solid-carbon byproduct. In this study, an extensive literature review was conducted to select and analyze several promising candidates for turquoise hydrogen production processes. The efficiency and economics of these processes were evaluated using stream data reported in the literature sources. The findings indicate that the levelized cost of hydrogen production (LCOH) is significantly influenced by the sales of byproducts, specifically the solid-carbon and carbon monoxide byproducts.

• Korean Chemical Engineering Research
• /
• 제43권3호
• /
• pp.331-343
• /
• 2005

연료전지와 수소를 사용하는 연료전지 자동차의 상용화를 위해서는 수소 공급용 수소 스테이션(hydrogen station)의 개발이 중요한 핵심 기반기술이다. 일반적으로 수소 스테이션은 탈황반응, 개질반응(reforming), 수성가스전환(WGS) 반응 및 수소분리(PSA) 장치로 구성된 수소제조 공정과 압축, 저장 및 분배 장치로 구성된 후처리(post-treatment) 공정으로 구성되어 있다. 본 총설에서는 수소 경제(hydrogen economy) 사회로의 진입을 위해 국내외에서 연구개발 중인 수소 스테이션에 대한 연구 개발 동향과 전망을 고찰하였다. 그리고 향후 풍력 및 태양열 등 재생 가능 에너지(renewable energy)원으로부터 물의 분해에 의한 수소제조 기술이 확립되기 전까지는 화석연료의 개질 반응이 수소를 제조하는 핵심기술이 될 것으로 판단된다. 따라서 화석연료의 탈황반응, 화석연료의 개질 반응에 의한 수소제조, CO 농도 저감을 위한 수성가스 전환반응 및 수소의 분리기술 등 수소 스테이션의 상용화에 필수적인 단위공정개발에 대한 최근의 연구동향을 정리하였다.

• 한국수소및신에너지학회논문집
• /
• 제32권6호
• /
• pp.506-513
• /
• 2021

The use of fossil fuels is a major contributor to the increase atmospheric greenhouse gas emissions. As such problems arise, interest in new and renewable energy devices, particularly fuel cells, is greatly increasing. In this study, various characteristics of mixed strains were observed in wastewater collected by the Jeonju Environment Office to investigate the effects of microorganisms on voltage generation and voltage generation of substrates, electrode materials, electrons, electron transport media, and ash microbial fuel cells. As a result of separately measuring the voltage generated during inoculation, the inoculation voltage of Escherichia coli K12 (E. coli K12) was 0.45 V, and the maximum inoculation voltage of the mixed strain was 1.2 V. Thereafter, voltage values were collected using a digital multimeter and the amount of voltage generated over time was measured. In the case of E. coli K12, the maximum voltage reached 0.45 V, and the cell voltage was maintained above 0.23 V for 140 hours. In contrast, for the mixed strain, the maximum voltage reached 1.2 V and the voltage was slowly decreased to 0.97 V. In addition, the degree of microbial adsorption to the electrod surface after the inoculation test was confirmed using a scanning electron microscope. Therefore, these results showed the possibility of purifying pollutants at the same time as power generation through the production of hydrogen ions using microorganisms and wastewater.

• 한국수소및신에너지학회논문집
• /
• 제27권4호
• /
• pp.386-403
• /
• 2016

Biofuels produced from biomass can be substituted for petroleum fuels due to GHG reduction, sustainability and environmental friendly. The process technologies that convert biomass into biofuels are varied and depend on the feedstocks. Microalgae are considered to be one of the most promising alternative source to the conventional feedstocks for biofuel. Microalgae can be converted to biodiesel, bioethanol, biogas and biojet fuel via thermolchemical and biochemical production technologies. This reviews discusses recent advance in understanding the effects of the characteristics of various processes on the production of biofuels using microalgae. The performances of microalgae based biofuel are compared.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 추계학술대회 논문집
• /
• pp.193-196
• /
• 2007

We developed and tested the high pressure hydrogen gas cylinder(type4) for fuel cell vehicle. The working pressure is 350bar. We conducted material tests, production tests and design qualification tests on the developed cylinders according to modified NGV2-2000(hydrogen). The high pressure hydrogen gas cylinder met all the design qualification requirements of ANSI/CSA NGV2-2000 and acquired NGV2 certification from independent inspection agency.

• 대한기계학회논문집B
• /
• 제31권4호
• /
• pp.384-391
• /
• 2007

Hydrogen-blending effects in flame structure and NO emission behavior are numerically studied with detailed chemistry in methane-air counterflow diffusion flames. The composition of fuel is systematically changed from pure methane to the blending fuel of methane-hydrogen through $H_2$ molar addition up to 30%. Flame structure, which can be described representatively as a fuel consumption layer and a $H_2$-CO consumption layer, is shown to be changed considerably in hydrogen-blending methane flames, compared to pure methane flames. The differences are displayed through maximum flame temperature, the overlap of fuel and oxygen, and the behaviors of the production rates of major species. Hydrogen-blending into hydrocarbon fuel can be a promising technology to reduce both the CO and $CO_2$ emissions supposing that NOx emission should be reduced through some technologies in industrial burners. These drastic changes of flame structure affect NO emission behavior considerably. The changes of thermal NO and prompt NO are also provided according to hydrogen-blending. Importantly contributing reaction steps to prompt NO are addressed in pure methane and hydrogen-blending methane flames.

• 한국전기화학회:학술대회논문집
• /
• 한국전기화학회 2004년도 추계총회 및 학술발표회
• /
• pp.36-36
• /
• 2004

• 한국수소및신에너지학회논문집
• /
• 제15권4호
• /
• pp.324-332
• /
• 2004

According to the rapid depletion of the fossil fuels, the electricity and hydrogen will gradually take charge of the future energy supply. Especially, in order to control the supply and demand of electricity, energy storage medium is necessary and this could be solved by the combination of water electrolysis and fuel cell. Although electricity can be generated from such alternative energies as hydropower, nuclear, solar, and wind-power resources, alternative energy storage medium is also required since regenerative energies, solar and wind-powers, are intermittent energy resources. In this regard, hydrogen production from water electrolysis was recognized as a superb method for electricity storage. In this work, the current development and economic status of alkaline, solid polymer, and high temperature electrolysis were reviewed, and then the practical use of water electrolysis technology were discussed.

• 한국수소및신에너지학회논문집
• /
• 제35권2호
• /
• pp.140-145
• /
• 2024

High temperature co-electrolysis of H₂O-CO₂ mixtures using solid oxide cells has attracted attention as promising CO₂ utilization technology for production of syngas (H₂/CO), feedstock for E-fuel synthesis. For direct supply to E-fuel production such as hydrocarbon and methanol, the outlet gas ratio (H₂/CO/CO₂) of co-electrolysis should be controlled. In this work, current voltage characteristic test and product gas analysis were carried out under various reaction conditions which could attain proper syngas ratio.