• 청정기술
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• 제23권3호
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• pp.314-324
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• 2017

To verify the viability of Co, Ru and Zr-based catalyst for $CO_2$ (dry) reforming reaction, catalysts were fabricated using cordierite, silicon carbide and rota monolithic substrates, and they were compared with the conventional $Co-Ru-Zr/SiO_2$ catalyst in terms of performance and durability. Cordierite monolith was showed high activity with the least amount of active component. In addition, when Cordierite monolith was coated with Co-Ru-Zr in various ways, most excellent performance was showed at a precursor solution coating method. In particular, when 0.9 wt% Co-Ru-Zr/Cordierite was used for reaction, it was observed that 95% $CO_2$ conversion was maintained for 300 h at $900^{\circ}C$.

• 한국수소및신에너지학회논문집
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• 제18권1호
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• pp.12-25
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• 2007

Numerical simulation of the natural gas steam reforming process for on-site hydrogen production in a $H_2$ fueling station was conducted on the basis of process material and heat balances. The effects of reforming parameters on the process efficiency of hydrogen production were investigated, and set-point values of each of the parameters to minimize the sizes of unit process equipments and to secure a stable operability of the reforming process were suggested. S/C ratio of the reforming reactants was found to be a crucial parameter in the reforming process mostly governing both the hydrogen production efficiency and the stable operability of the process. The operation of the process was regarded to be stable if the feed water(WR) as a reforming reactant could evaporate completely to dry steam through HRSG. The optimum S/C ratio was 3.0 where the process efficiency of hydrogen production was maximized and the stable operability of the process was secured. The optimum feed rates of natural gas(NGR) and WR as reforming reactants and natural gas(NGB) as a burner fuel were also determined for the hydrogen production rate of $27\;Nm^3/h$.

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.21-30
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• 2015

Ceramic foams are prepared as positive images corresponding to a plastic foam structure which exhibits high porosities (85-90%). This structure makes the ceramic foams attractive as a catalyst in a dry reforming process, because it could reduce a high pressure drop problem. This problem causes low mass and heat transfers in the process. Furthermore, the reactants would shortly contact to catalyst surface, thus low conversion could occur. Therefore, this research addressed the preparation of dry reforming catalysts using a sol-gel catalyst preparation via a polymeric sponge method. The specific objectives of this work are to investigate the effects of polymer foam structure (such as porosity, pore sizes, and cell characteristics) on a catalyst performance and to observe the influences of catalyst preparation parameters to yield a replica of the original structure of polymeric foam. To accomplish these objectives industrial waste foams, polyurethane (PU) and polyvinyl alcohol (PVA) foams, were used as a polymeric template. Results indicated that the porosity of the polyurethane and polyvinyl alcohol foams were about 99% and 97%. Their average cell sizes were approximate 200 and 50 micrometres, respectively. The cell characteristics of polymer foams exhibited the character of a high permeability material that can be able to dip with ceramic slurry, which was synthesized with various viscosities, during a catalyst preparation step. Next, morphology of ceramic foams was explored using scanning electron microscopy (SEM), and catalyst properties, such as; temperature profile of catalyst reduction, metal dispersion, and surface area, were also characterized by $H_2-TPR$ and $H_2-TPD$ techniques, and BET, respectively. From the results, it was found that metal-particle dispersion was relatively high about 5.89%, whereas the surface area of ceramic foam catalysts was $64.52m^2/g$. Finally, the catalytic behaviour toward hydrogen production through the dry reforming of methane using a fixed-bed reactor was evaluated under certain operating conditions. The approaches from this research provide a direction for further improvement of marketable environmental friendly catalyst production.

• 한국수소및신에너지학회논문집
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• 제27권5호
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• pp.554-561
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• 2016

Depending on the Bio-gas sources, main component gases of $CH_4$ and $CO_2$ are shown to be variously present in amounts. For the anaerobic digester, The concentration of $CH_4$ and $CO_2$ in the gases are 60~70 and 30~35 vol%. For the landfill gas, $CH_4$ and $CO_2$ are 40~60 and 40~60 vol%. For the food wastes, $CH_4$ and $CO_2$ are 60~80 and 20~40 vol%, respectively. In this study, maximum conversion rates of $CO_2$ were obtained from the variety of concentrations of $CH_4$ and $CO_2$ by the catalysts of reforming reactions. Moreover, in order to get maximum producing amount of synthetic gas, experimental studies were performed to optimize the reaction variables. On the basis of $CH_4$, 243 ml, R [$CH_4/(O2+CO_2)$] value were varied from 0.8 to 1.35, in the study of $CH_4$ and $CO_2$ reforming reactions. It was shown that the optimal results were obtained for 1.35 of R value. And also, at $850^{\circ}C$ and 1 atm, the production rate of synthetic gas was 90% and the conversion rates of $CH_4$ and $CO_2$ were higher than 99% and 90%, respectively.

• 에너지공학
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• 제19권4호
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• pp.240-245
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• 2010

화석연료는 사용 후 재생이 불가능하고 매장량이 한정되어 있으며, 연소 시 발생되는 각종 공해물질로 인해 환경문제를 야기하고 있다. 이러한 맥락에서 차세대 청정대체에너지로서 주목을 받고 있는 것이 바로 수소에너지이다. 현재 가장 경제성이 있는 수소제조방법으로 알려진 천연가스 Steam Reformig(SRM)은 천연가스의 매장량 한계성으로 인해 그 제조비용이 높아지고 있어, 바이오매스 및 유기성 폐기물의 가스화를 통한 수소생산방법이 자원의 재순환, 페기물 처리, 열원의 이용, 직접적인 $CO_2$ 삭감 등의 부수적인 효과가 높아 경제성 있는 수소제조법으로 많은 연구가 진행되고 있다. 이에 본 연구에서는 잠재적으로 고갈 염려가 있는 화석연료를 대체하고, 화석연료의 연소 시 발생되는 환경문제를 해결하고자 열분해로와 고온개질기로 구성된 Pilot-scale Two Stage Gasifier를 개발하고, 본 장치 내에서의 biomass의 가스화 특성을 평가하고자 한다. 열분 해로에서의 가스화 실험 결과, 열분해로의 전환율은 약 70%로 나타났으며, $H_2$, $CH_4$, CO, $CO_2$의 평균 생성량은 각각 16.7, 11.3, 37.2, 26.6 L/mim의 결과를 보였다. 고온개질기로부터의 생성가스 수율의 결과로부터, 고온개질기에 적용된 $1100^{\circ}C$의 초고온에서의 개질 반응에 의해 $CH_4$의 대부분이 환원됨을 확인할 수 있었다. 본 연구로부터 개발된 장치의 냉가스 효율은 53.2%로 비교적 높은 결과가 얻어졌으며, 수소에 대한 평균 생성량은 55.4 L/min의 결과를 보였다.