• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1029-1038
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• 2008

Transition-metal-oxide-incorporated hydrotalcites were prepared by hydrothermal reaction of their synthetic mixtures containing precursors of transition metal oxides and their properties of nitrogen dioxide adsorption was investigated. The dispersion of transition metal oxides on the hydrotalcites and the amount and the state of nitrogen dioxide adsorbed on them were examined by using XRD, SEM, XPS, nitrogen adsorption, a gravimetric adsorption system, FT-IR spectroscopy and temperature programmed desorption techniques. Transition metal oxides were mainly incorporated on their surface and the incorporation of iron and nickel oxides to the hydrotalcites increased their adsorption amounts of nitrogen dioxide. The dispersion of iron oxide on the hydrotalcites was effective in increasing the amount of nitrogen dioxide adsorption, while too much amount of iron oxide incorporation reduced the amount of nitrogen dioxide adsorption due to masking of surface basic sites by agglomerated iron oxide. Although the incorporation of iron oxide to the hydrotalcites lowered the adsorption strength of nitrogen dioxide, the incorporation of it with a proper amount enhanced the amount of nitrogen dioxide adsorption and the stability against the hydrothermal treatment.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.85-88
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• 2007

고정층반응기에서 여러 가지 전이금속으로 치환된 하이드로탈사이트($[M_xMg_{6-x}Al_2(OH)_{16}(CO_3)^{2-}]{\cdot}H_2O;$ M: 전이금속(Ni, Mn, Co, Cu, Zn) x: 전이금속 치환비($x=0.5{\sim}6$))를 합성하고 이를 소성한 후 메탄의 부분산화 반응에 사용하였다. 반응 시 도입되는 $CH_4/O_2$비는 2로 하고 $VHSV=120,000cm^3/g$ h, 온도를 $500^{\circ}C$ 부터 $50^{\circ}C$ 간격으로 하여 $800^{\circ}C$까지 수행하였다. 실험결과 다른 전이금속들 중에서 니켈로 치환된 촉매가 대체적으로 부분산화반응을 촉진시키는데 좋은 것으로 나타났으며, 실험 결과 니켈의 hydrotalcite 중의 치환비(x)에 따른 차이는 별로 없었다.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.499-502
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• 2008

고정층반응기에서 니켈이 치환된 하이드로탈사이트($Ni_3Mg_3Al_2(CO_3)(OH)_{{16}{\cdot}n}H_2O$ ; n=3$\sim$5)를 합성하고 여기에 세리아를 첨가 후 소성하여 얻은 촉매를 사용하여($Ce_xNi_3$-HTlc ; x=0.3$\sim$1.2) 메탄의 부분산화 반응실험을 수행하였다. 세리아가 첨가되지 않은 촉매는 반응 초기 활성이 세리가가 소량 첨가된 ($Ce_{0.3}Ni_3$-HTlc) 촉매보다 우수하였으나 장시간 반응에서는 차차 활성이 저하되었으나, $Ce_{0.3}Ni_3$-HTlc의 활성은 30시간까지 일정하게 유지 되었다. 세리아 함량이 많아 질수록 촉매 활성은 점차 저하되었으며, $Ce_{1.2}Ni_3$-HTlc 는 촉매활성이 매우 낮았다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.753-756
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• 2009

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.387-390
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• 2008

Ni/MgAl 촉매상에서 LPG의 수증기 개질반응을 반응온도 $700{\sim}800^{\circ}C$, 공간속도 $20,000h^{-1}$, 수증기/탄소 비율 $1.0{\sim}3.0$인 조건으로 대기압하에서 수행하였다. 본 연구에서 사용된 촉매들은 공침법으로 제조하였으며, 하이드로탈사이트 구조에서 Ni-MgO 구조로 변환되는 과정에서 활성금속인 니켈이 고분산되는 장점을 지니고 있다. 제조된 촉매는 함침법으로 제조된 촉매보다 활성이 잘 유지되었으며 탄소침적에 대한 내구성 또한 향상되었으나 완벽하게 해결되지는 못하였다. 따라서 이와 같은 문제점을 해결하기 위해 귀금속이 modified된 Ni/MgAl 촉매를 제조하고 반응 특성을 비교하였다. Rh-Ni/MgAl 촉매는 LPG 수증기 개질 반응에서 1024시간동안 활성이 유지됨을 확인하였을 뿐만 아니라 탄소침적 또한 발생하지 않음을 확인하였다.

• Journal of the Korean Institute of Gas
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• v.26 no.5
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• pp.16-21
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• 2022

The reaction rate of a catalyst for producing hydrogen using the methanol steam reforming reaction was studied. It was prepared by impregnating copper, which is often used in methanol synthesis, as the main active metal, using hydrotalcite, which has excellent porosity and thermal stability, high specific surface area, weak Lewis acid point, and basicity, as a support. Activation energy and Pre-exponential factors were identified. In this study, the activation energy of the hydrotalcite catalyst impregnated with 20 wt% copper was calculated to be 97.4 kJ/mol and the Pre-exponential was 5.904 × 10¹⁰. Process simulation was performed using the calculated values and showed a similar tendency to the experimental results.

• Journal of the Korean Institute of Gas
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• v.27 no.1
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• pp.78-85
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• 2023

Fixed-bed reactor Computational Fluid Dynamics (CFD) simulation of methanol steam reforming reaction was performed using the intrinsic kinetic data of the copper-impregnated hydrotalcite catalyst. The activation energy of the copper hydrotalcite catalyst obtained from the previous study results was 97.4 kJ/mol, and the pre-exponential was 5.904 × 10¹⁰. Process simulation was performed using the calculated values and showed a similar tendency to the experimental results. And the conversion rate according to the change of the reaction temperature (200 - 450 ℃) and the molar ratio of methanol and water was observed using the intrinsic kinetic data. In addition, mass and heat transfer phenomena analysis of a commercial reactor (I.D. 0.05 - 0.1m, Length 1m) was predicted through axial 2D Symmetry simulation using the power law model of the above kinetic constants.

• New & Renewable Energy
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• v.4 no.2
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• pp.39-44
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• 2008

Partial oxidation of methane was carried out by ceria-promoted Ni-substituted hydrotalcite-derived catalysts ($Ce_xNi_3$-HTlc ; x=$0.3{\sim}1.2$) in a fixed-bed reactor. The Ce/Ni ratio of 0.3/3 in the catalyst showed the best catalytic activity but the Ce/Ni ratio became higher above 0.3/3, the catalyst became less active in short-term tests. No ceria promoted catalyst was started to decrease $CH_4$ conversion after 20 h but the Ce/Ni ratio 0.3/3 catalyst was kept its stability in long-term tests.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.90-91
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• 2017

Concrete can be used semi-permanently unless the steel is corroded. However, the concrete exposed to the marine environment is exposed to sea breeze, so chloride ions penetrate into the concrete and the steel is corroded accordingly. In order to solve these problems, there is a method of increasing the covering depth of the concrete and an application of the epoxy paint to the steel. In this study, the hydrotalcite type corrosion inhibitor was mixed with the concrete and the compressive strength, chloride diffusion coefficient and the corrosion properties of the steel were examined.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.243.2-243.2
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• 2010

현재 바이오디젤(Bio diesel)은 유지와 메탄올을 염기촉매를 넣고 전이에스테르화(Trans-esterification)반응하여 생산한다. 생산된 1세대 바이오 디젤은 분자 내 산소가 다량 함유되어 여러 가지 단점을 가지기 때문에 전이에스테르화 반응을 대체한 탈산소(Deoxygenation)반응이 주목 받고 있다. 본 연구에서는 유리지방산(Free fatty acid, FFA)인 올레익 산(Oleic acid)의 탈산소반응을 수행하였다. 하이드로탈사이트(Hydrotalcites) 구조인 MgO-$Al_2O_3$(MgO=70 wt%)를 6시간 동안 $500^{\circ}C$에서 예비소성(Pre-calcination)하여 담체로 사용하였다. 제조된 MgO-$Al_2O_3$ 담체에 함침법(Incipient wetness method)으로 20 wt% Ni을 담지 시켰다. 제조된 Ni/MgO-$Al_2O_3$촉매는 소성온도를 변화시켜 반응 실험을 수행하였다. TPR 분석을 통해 산화-환원특성을 분석하였고 생성물의 원소분석을 통해 생성물의 산소함량을 측정하였다.