• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.698-706
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• 1996

Dehydrogenation of methanol to produce formaldehyde was carried out over various silica-alumina catalysts doped with alkali metals in a continuous flow system. The reaction was rather dependent on Lewis acid than Br${\ddot{o}}$nsted acid suggesting that dehydrogenation of methanol was an electronic reaction. The Br${\ddot{o}}$nsted acid sites on silica-alumina were neutralized by doping with alkali metals, and the neutralization effect of Br${\ddot{o}}$nsted acid was dependent on the electron-donating capacity of the dopant metals. Activation energy for dehydrogenation of methanol decreased when Br${\ddot{o}}$nsted acid was neutralized by doping with K.

• Resources Recycling
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• v.20 no.2
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• pp.74-81
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• 2011

The dry method and wet method are currently used for the recovery of platinum group metals (Pt, Rh, Pd) contained in spent automobile catalysts. The study herein aims to identify the melting condition and optimum collector metal in accordance with a comparison of each concentration change in melting waste catalysts, using Fe and Cu in a basic experiment to recover waste catalysts through application of the dry melting method. As a summarized result of the experiment herein, it was determined to be more advantageous to use Fe as a parent material rather than Cu from the aspect of recollection rate, and the concentration change rate of platinum group metals within slag was greatly enhanced at $1,600^{\circ}C$ melting condition rather than at $1,500^{\circ}C$ in terms of melting processing temperature. The mean concentration of platinum group metals - Rh, Pd and Pt - within slag after a melting process at $1,600^{\circ}C$ were 6.21 ppm, 5.98 ppm and 6.97 ppm. The Rh and Pd were 50.58% and 55.31% respectively greater than the concentration change rate of platinum group metals in slag at a melting temperature of $1,500^{\circ}C$. However, since the initial concentration of Pt within the waste catalysts was 12.9 ppm, is relatively low, it was difficult to compare concentration change rates after the melting process.

• Resources Recycling
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• v.30 no.3
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• pp.18-29
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• 2021

Platinum group metals (PGMs) are used in a wide range of application fields such as catalysts, electronic devices, electrodes, electrical devices, fuel cells and high temperature materials due to their excellent electrical and thermal conductivity as well as chemical resistivity. Platinum group elements are generally associated with nickel-copper sulfides in magmatic rocks. Depending on the relative concentrations of the PGMs, they are produced either as the primary products or as by-products of the nickel and copper. However, PGMs natural resource deposits are strictly limited in countries such as South Africa and Russia. The annual supply of PGMs is only under 500 t. Considering the limited supply of PGMs, there will be a noticeable increase in the supply risk associated with PGMs in the near future. Therefore, it is extremely important to recover PGMs from secondary resources such as spent catalysts. This paper reviews on overview of PGMs extraction and recycling processes.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.401-410
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• 2016

The $Pt-Sn/Al_2O_3$ catalysts mixed with metal oxides for propane dehydrogenation were studied. $Cu-Mn/{\gamma}-Al_2O_3$, $Ni-Mn/{\gamma}-Al_2O_3$, $Cu/{\alpha}-Al_2O_3$ was prepared and mixed with $Pt-Sn/Al_2O_3$ to measure the activity for propane dehydrogenation. As standard sample, $Pt-Sn/Al_2O_3$ catalyst mixed with glassbead was adopted. In the case of catalytic activity test after non-reductive pretreatment of catalyst and metal oxide, $Pt-Sn/Al_2O_3$ mixed with $Cu-Mn/{\gamma}-Al_2O_3$ showed higher conversion of 15% and similar selectivity at $576.5^{\circ}C$, compared to conversion of 8% in standard sample. In the case of catalytic activity test after reductive pretreatment of catalyst and metal oxde, $Cu/{\alpha}-Al_2O_3$ showed higer yield than standard sample. But, increase of yield of most of samples after reductive pretreatment was not significant, so it was found that lattice oxygen of $Cu-Mn/{\gamma}-Al_2O_3$ is effective to propane dehydrogenation.

• Resources Recycling
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• v.3 no.1
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• pp.17-24
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• 1994

Recovery of precious metal values from petrochemical spent catalyst is important from the viewpoint of environmental protection and resource recycling. Two types of spent catalysts were used in this study. One used in the manufacture of ethylene contains 0.3% Pd in the alumina substrate. The other used in oil refining contains 0.3% Pt and 0.3% Re. Both spent catalysts are roasted to remove volatile matters as carbon and sulfur. Then, metallic Pd powder from Pd spent catalyst is obtained in the course of grinding, hydrochloric acid or aqua regia leaching and cementation with iron. For the recovery of Pt and Re from Pt-Re spent catalyst, Pt and Re are leached with either HCI or aqua regia, first. Metallic Pt powder is recovered from the leach solution by cementation with Fe powder. Re in sulfide form is precipitated by the addition of sodium sulfide to the solution obtained after Pt recovery. It is found that 6N HCI can be successfully used as leaching agent for both types of spent catalyst. 6N HCI is considered to be better than aqua regia in consideration of reagent and equipment cost.

• Journal of the Korean Institute of Gas
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• v.11 no.2 s.35
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• pp.25-30
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• 2007

The catalysts for decomposition reaction of acetaldehyde were investigated. The catalysts were prepared with transition metal Ni, Mo, Al on ${\gamma}-Al_2O_3$ support by impregnation method. Physio-chemical properties of catalysts were characterized by SEM-EDS, XRD, XPS, BET and TPR techniques. The conversion efficiency of catalysts for acetaldehyde was measured in the temperature range of $150{\sim}500^{\circ}C$ by GC through the micro reactor system. The 8 wt% $Ni/{\gamma}-Al_2O_3$ was found to be the most active catalyst of mono-metal catalysts tested, and the 1-3 wt% $Ni-Al/{\gamma}-Al_2O_3$ showed higher conversion efficiency than other bimetallic catalysts.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.925-934
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• 1994

Nickel recovered from the spent oil-hydrogenation catalysts was used in hydrogenation catalyst preparation. The spent catalyst contains approximately 21.8% Ni, 0.7% Mg, and small quantities of Al, Fe, and Zn. Nickel recovery was obtained by inorganic acid digestion in the order of HCI>$NHO_3$>$H_2SO_4$. For $HNO_3$, 3hour extraction with 3N solution was satisfactory. In the PH range of 6.5~9.0, Ni recovery was higher, but metallic impurities were found to be coprecipitated. The PH in the range of 7.0~9.0 seems to be the optimum condition for separation to obtain acceptable Ni precipitates without the decrease of purity. The catalysts prepared with reclaimed nickel by wet reduction methods showed catalytic activities close to those prepared using reagent nickel in the oil hydrogenation reaction. The surface areas of the support do not seem to affect the catalytic activity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.644-650
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• 2021

This study characterized the reforming of methane with carbon dioxide, which is a major cause of global warming. The methane decomposition reaction with carbon dioxide was carried out using transition metal catalysts. The reactivity of tin was lower than that of a transition metal, such as nickel and iron. Most of the decomposition reaction occurred in the solid state. The melting point of tin is 505.03 K. Tin reacts in a liquid phase at the reaction temperature and has the advantage of separating carbon produced by the decomposition of methane from the liquid tin catalyst. Therefore, deactivation due to the deposition of carbon in the liquid tin can be prevented. Methane decomposition with carbon dioxide produced carbon monoxide and hydrogen. Ni was used to promote the catalyst performance and enhance the activity of the catalyst and lifetime. In this study, catalysts were synthesized using the excess wet impregnation method. The effect of the reaction temperature, space velocity was measured to calculate the activity of catalysts, such as the activation energy and regeneration of catalysts. The carbon-deposited tin catalyst regeneration temperature was 1023 K. The reactivity was improved using a nickel co-catalyst and a water supply.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.168.1-168.1
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• 2017

화석연료를 대체하기 위한 에너지원으로서 수소에너지에 대한 연구가 활발히 진행되고 있다. 수전해는 무한 청정한 물을 전기분해하여 수소를 생산하는 기술로써 대표적으로 알칼리 수전해(alkaline water electrolysis, AWE)와 고분자 전해질막 수전해(polymer electrolyte membrane water electrolysis, PEMWE)가 있다. 그 중, AWE는 알칼리 분위기에서 물분해 반응이 진행되어 촉매의 부식 위험성이 비교적 낮기 때문에 상대적으로 저렴한 비귀금속 산화물 촉매를 사용할 수 있다는 장점이 있다. 본 연구에서는 비귀금속인 Cu, Co를 이용하여 $CuCoO_4$를 합성한 후 산소 발생 촉매 물질로 활용하여 산소 발생 반응(Oxygen Evolution Reaction, OER)특성을 고찰하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.113.1-113.1
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• 2010

본 연구에서는 중 소형 SOFC에 적용할 수 있는 연료 변환 시스템으로 자체 기동 및 독립운전이 가능한 천연가스 자열개질(ATR) 반응기를 $10Nm^3/hr$급으로 개발하고자한다. 설계된 천연가스 자열개질기는 자열개질 촉매를 코팅한 금속 모노리스형 촉매체를 반응기 내에 장착함으로써 반응열을 신속하게 제거 또는 공급할 수 있는 시스템으로 구성되었다. 이는 금속 모노리스의 뛰어난 열전도 능력에 의해 반응기 내의 촉매층 전체 온도 분포를 균일하게 유지할 수 있는 저에너지형 자열개질 반응기이다. 또한 빠른 기동 특성을 실현하기 위하여 전기 발열식 촉매체(EHC ; Electically Heated Catalyst)를 장착한 start-up 시스템을 적용하여 천연가스 자열개질 반응기의 신속한 기동과 장치 간편화를 실현하였으며, 합성 syngas의 배열 회수를 위한 최적 열교환 시스템을 설계/적용함으로써 에너지 효율 향상을 도모하였다. 이와 같은 촉매 및 구조 시스템을 가지는 천연가스 자열개질 반응용 소형 연료변환 시스템을 원통형의 이중관 구조로 구성하고, 독립운전 모드로 개발함으로써 소형 SOFC의 연료 변환장치의 적용에 용이하게 하고자 한다.