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폐기물 가스화 합성가스로부터 고순도 수소 생산을 위한 WGS 반응용 백금 촉매 연구
정대운,장원준,심재오,노현석 한국폐기물자원순환학회 2013 한국폐기물자원순환학회지 Vol.30 No.1
Simulated waste-derived synthesis gas has been tested for hydrogen production through water gas shift (WGS) reaction in the temperature range of 240oC ~ 400oC over supported Pt catalysts prepared by an incipient wetness impregnation method. MG30, MgO, ZrO2, Al2O3 and CeO2 were employed as supports for WGS reaction in this study. 1 wt.% Pt/ CeO2 catalyst exhibited the highest CO conversion as well as 100% CO2 selectivity. This is due to easier reducibility of Pt/CeO2 and high oxygen mobility and oxygen storage capacitiy of CeO2. Pt/CeO2 catalyst can be a promising catalyst for WGS reaction from waste-derived synthesis gas.
DEA 모형을 활용한 전문건설기업 업종별‧연도별 효율성 분석 연구
정대운,김경래 대한건축학회 2023 대한건축학회논문집 Vol.39 No.8
This study utilized the DEA model to analyze the efficiency of various specialty construction industries. Data from 2017 to 2021, covering520 specialty construction companies, were examined. The findings indicated that these companies were inefficient in terms of scale,highlighting the need for improvements through measures like reducing production factors, such as scale reduction. Among the specialtyconstruction industries, the reinforced concrete construction sector demonstrated significantly higher efficiency compared to others, emphasizingthe importance of benchmarking between these industries. The outbreak of the COVID-19 pandemic resulted in a temporary decline inefficiency within the specialty construction industry in 2020, but a recovery was observed in 2021. However, operating profit efficiency saw asubstantial decline in 2021, primarily due to soaring raw material prices. Consequently, it was deduced that the increase in sales efficiencyresulted from these price surges. The study identified the reinforced concrete construction industry of metal, window, roofing, prefabricationconstruction, and painting, wetting, waterproofing of the stone construction industry as most impacted by escalating construction material costs. Therefore, it is crucial for specialty construction companies to enhance efficiency by reducing input factors, with a specific focus onefficiency management strategies considering rising raw material prices for the aforementioned industries. It is important to note that thisstudy only analyzed specialty construction companies subject to external audits, and factors like technological changes were not considered. The analysis primarily focused on relative efficiency within the same industry category. 본 연구는 DEA 모형을 이용하여 전문건설업 업종별 효율성을 분석하였다. 분석자료는 2017년부터 2021년까지 총 520개 전문건설기업의 자료를 활용하였다. 분석결과, 전문건설기업은 규모 면에서 비효율적인 것으로 나타났다. 따라서 전문건설기업은 투입요소를 절감하여 효율성을 개선할 필요가 있다. 또한 전문건설업 중 철근‧콘크리트공사업의 효율성이 타 업종에 비해 월등히 높아 전문건설업종 간의 벤치마킹도 필요한 것으로 나타났다. 코로나19 대유행 이후 2020년 전문건설업의 효율성이 감소했지만, 2021년 효율성은 다시 상승하였다. 그러나 영업이익만을 산출요소로 적용한 효율성 분석결과에서는 2021년 효율성이 크게 감소하였다. 즉, 원자재 가격 급등에 따라 매출액이 포함된 2021년 효율성이 높아진 것으로 분석되었다. 마지막으로 건축자재비 상승의 영향을 가장 많이 받은 업종은 철근·콘크리트공사업, 금속창호·지붕건축물조립공사업, 도장·습식·방수·석공사업으로 분석되었다. 이에 따라 전문건설기업은 투입요소를 절감하여 효율성을 향상시켜야 하며, 특히 철근․콘크리트공사업과 금속창호․지붕건축물조립공사업, 도장·습식·방수·석공사업은 원자재 가격 상승에 대비한 효율성 관리전략이 마련되어야 하겠다. 본 연구에서는 외부감사 대상인 전문건설기업만을 분석대상으로 한정한 점과 기술의 변화 등 외부적 요인을 판단할 수 없다는 점, 업종별로 동일한 범주에서 상대적 효율성을 분석했다는 점 등의 한계점을 갖는다.
Single stage WGS 반응용 Pt-Na/CeO2 촉매 연구
정대운,심재오,장원준,노현석 한국수소및신에너지학회 2012 한국수소 및 신에너지학회논문집 Vol.23 No.2
Na promoted Pt/CeO2 catalysts with various Na amounts (1, 2, and 3wt%) have been applied to water gas shift reaction (WGS) at a gas hourly space velocity (GHSV) of 45515 h-1. 1wt%Pt-2wt%Na/CeO2 catalyst exhibited the highest WGS activity at 240oC among the catalysts prepared in this study. In addition, 1wt%Pt-2wt%Na/CeO2 catalyst showed relatively stable activity with time on stream. The high activity/stability of 1wt%Pt-2wt%Na/CeO2 catalyst was correlated to its easier reducibility and higher oxygen storage capacity (OSC). As a result, 2wt% Na promoted Pt/CeO2 can be a promising candidate catalyst for the single stage WGS, which requires high intrinsic activity at very high GHSV.
Comparative study on cubic and tetragonal Cu–CeO2–ZrO2 catalysts for water gas shift reaction
정대운,노현석,장원준,나현석,심재오,Ajay Jha 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.27 No.-
Cu–Ce0.8Zr0.2O2 and Cu–Ce0.2Zr0.8O2 catalysts have been applied for water gas shift reaction tounderstand the effect of cubic/tetragonal structure of CeO2–ZrO2 support. Cubic Cu–Ce0.8Zr0.2O2 catalystshows higher activity (17.4% at 320 8C) than tetragonal Cu–Ce0.2Zr0.8O2 catalyst at the high gas hourlyspace velocity of 72,152 h 1 due to the enhanced oxygen mobility and high Cu dispersion (7.8%). Inaddition, cubic Cu–Ce0.8Zr0.2O2 catalyst exhibits a stable activity at 320 8C for 25 h resulting from astrong resistance against sintering.