Effects of Na content in Na/Ni/SiO₂ and Na/Ni/CeO₂ catalysts for CO and CO₂ methanation

Le, Thien An,Kim, Tae Wook,Lee, Sae Ha,Park, Eun Duck Elsevier 2018 CATALYSIS TODAY - Vol.303 No.-

<P><B>Abstract</B></P> <P>CO and CO<SUB>2</SUB> methanation over Na/Ni/SiO<SUB>2</SUB> and Na/Ni/CeO<SUB>2</SUB> catalysts with different Na contents (0, 0.1, and 1wt%) were studied. N<SUB>2</SUB> physisorption, H<SUB>2</SUB> chemisorption, temperature-programmed reduction with H<SUB>2</SUB>, CO<SUB>2</SUB> chemisorption, temperature-programmed desorption of CO<SUB>2</SUB>, temperature-programmed oxidation, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy were employed to characterize the catalysts. Even just 0.1wt% Na was observed to have a negative effect on CO methanation for the Na/Ni/SiO<SUB>2</SUB> and Na/Ni/CeO<SUB>2</SUB> catalysts owing to surface blockage of the Ni metal. The negative effect of Na on CO<SUB>2</SUB> methanation was also observed for the Na/Ni/CeO<SUB>2</SUB> catalysts. Conversely, Na exhibited a positive effect upon CO<SUB>2</SUB> methanation over the Na/Ni/SiO<SUB>2</SUB> catalysts. The different effect of Na on CO<SUB>2</SUB> methanation is closely related to the amount of CO<SUB>2</SUB> chemisorbed on the catalysts. Stable catalytic activity for CO and CO<SUB>2</SUB> methanation was observed for Ni/SiO<SUB>2</SUB>, Na/Ni/SiO<SUB>2</SUB>, and Ni/CeO<SUB>2</SUB>. However, the Na/Ni/CeO<SUB>2</SUB> catalyst was deactivated during CO methanation owing to coke formation following olefin production. However, this catalyst was stable for CO<SUB>2</SUB> methanation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CO methanation activity decreases with Na content over Na/Ni/SiO<SUB>2</SUB> and Na/Ni/CeO<SUB>2</SUB>. </LI> <LI> CO<SUB>2</SUB> methanation activity decreases with Na content over Na/Ni/CeO<SUB>2</SUB>. </LI> <LI> The promotional effect of Na on CO<SUB>2</SUB> methanation was confirmed over Na/Ni/SiO<SUB>2</SUB>. </LI> <LI> The addition of Na decreases the surface area of Na/Ni/SiO<SUB>2</SUB> and Na/Ni/CeO<SUB>2</SUB>. </LI> <LI> CO<SUB>2</SUB> methanation activity is related to the amount of CO<SUB>2</SUB> chemisorbed on the catalyst. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Raney Ni Catalysts Derived from Different Alloy Precursors Part II. CO and CO2 Methanation Activity

Gun Dae Lee,문명준,박성수,홍성수,Jeong Hwan Park 한국화학공학회 2005 Korean Journal of Chemical Engineering Vol.22 No.4

Catalytic activity, in conjunction with reaction mechanism, was studied in the methanation of CO and CO2 on three Raney Ni catalysts derived from different Ni-Al alloys using different leaching conditions. Main products wereCH4 and CO2 in CO methanation, and CH4 and CO in CO2 methanation. Any other hydrocarbon products were notobserved. Over all catalysts, CO methanation showed lower selectivity to methane and higher activation energy thanCO2 methanation. The catalyst derived from alloy having higher Ni content using more severe leaching conditions,namely higher reaction temperature and longer extraction time, showed higher specific activity and higher selectivityto methane both in CO and CO2 2 methanation on Raney Ni catalyst, catalytic activity wasseen to have close relation with the activity to dissociate CO.

CO₂ methanation 반응시 공존가스(O₂, CH₄, H₂S)에 대한 영향

안정윤,장순웅,정우진,김성수,이상문,노연희,정석주 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

최근 산업의 발전에 따라 에너지 사용량과 함께 이산화탄소의 배출 또한 증가하는 추세이다. CO₂는 온실가스 물질 중 가장 많이 존재하는 물질이며, 많은 연구자들은 다양한 CO₂ 저감 연구를 수행하였다. 특히 CO₂ methanation 연구는 1M CO₂를 1M CH₄로 변환시켜 에너지원으로 사용하는 CCU 기술로 4M H₂를 소모한다. CO₂ methanation에 이용되는 고효율 촉매 연구는 많이 진행되었으나 실제 현장에서 발생되는 실 가스에 대한 연구는 미비한 실정이다. 특히 CO₂가 많이 발생되는 소화조 실가스는 O₂, CH₄, H₂S 등 CO₂ methanaton 촉매에 악영향을 끼치는 가스가 함께 유입된다. 이 물질들에 대한 CO₂ methanation 촉매의 악영향에 대한 연구가 전무하다. 본 연구진은 소화조에서 발생되는 O₂, CH₄, H₂S 등의 영향을 확인하기 위해 고효율 촉매를 이용하여 O₂, CH₄, H₂S의 농도별 CO₂ methanation 효율 평가를 수행하였다. ^** 본 연구는 환경부 글로벌탑 환경기술개발사업으로 지원받은 과제임(과제번호:2016002200005)

The reaction kinetics of CO2 methanation on a bifunctional Ni/MgO catalyst

A. Loder,M. Siebenhofer,S. Lux 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.85 No.-

A bifunctional Ni/MgO catalyst was prepared to catalyze CO2 methanation and make use of CO2 as anabundant hydrogen storage facility. The effect of Ni loading and MgO quality on the rate of methanationwas tested in a temperature range of 533–648 K. The Ni loading was varied between 0 to 27 wt.% onMgO. To investigate the impact of matrix elements, a MgO/CaO support was tested with 21 wt.%. nickelloading. Further, the role of MgO in the bifunctional catalyst was proven. The reaction kinetics wasmodeled with a Langmuir–Hinshelwood approach considering the bifunctional character of thecatalyst. Nickel provides the adsorbent capacity for hydrogen and is highly selective for methane. MgOactivates CO2 through chemisorption. Increasing Ni loading of the catalyst increased the rate of CO2conversion. According to the results, the mechanism of CO2 methanation did not change with Niloading. The Ni/MgO catalyst acted as a robust, active and highly selective catalyst for CO2methanation. With CO2 conversion of 87%, the selectivity to methane was99%. Besides excellent catalytic activitythe catalysts suffice the necessity of simple catalyst preparation, usage and recyclability for industrialapplicability of CO2 methanation.

CO₂ methanation반응을 이용한 하수처리장 내 부생가스의 에너지화에 관한 연구

문대헌 ( Dea-hyun Moon ),안정윤 ( Jeong-yoon Ahn ),이시진 ( Si-jin Lee ),장순웅 ( Soon-woong Chang ) 한국폐기물자원순환학회(구 한국폐기물학회) 2017 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2017 No.-

유기성폐기물(음식물, 하수슬러지 등)은 2005년부터 육상 직매립이 금지되었고, 2006년에 발효된 런던협약에 따라 2013년 1월부터 해양투기 또한 금지되어 폐기물의 처리 및 재활용이 시급한 실정이다. 따라서, 이러한 유기성 폐기물의 효과적인 자원화 방법 중 하나인 혐기성소화가 각광받고 있는 실정이며, 혐기성소화조에서 발생되는 바이가스는 일반적으로 CH₄ 50~90%, CO₂ 10~50%, 소량의 H₂S 및 NH4로 알려져 있다. 이러한 바이오가스의 정제방법으로는 탄소흡착법, 막분리법 등이 있으나 높은 운전비용과 공정구성의 어려움, ₂차 폐기물 발생 등 많은 문제를 일으키고, CO₂의 재활용이 아닌 폐기시키고 있어 자원순환적인 측면에서 바람직하지 못하다. CH4의 전환방법중 하나인 CO₂ methanation반응은 1M의 CO₂와 4M의 H₂가 반응하여 1M의 CH₄와 ₂M의 H₂O가 생성되는 반응이다. CO₂는 열역학적으로 매우 안정된 물질로, 반응에 필요한 에너지를 공급하기 위해서는 수소 등과 같은 높은 에너지의 환원제를 같이 반응에 참여시켜 주어야 한다. 그러나 열역학적 평형으로 인해 전환이 제한되는 경우가 많아, 적절한 반응속도와 선택도를 달성하기 위해 촉매가 요구되며, CO₂ methanation 반응에 사용되는 촉매는 주로 Ni, Fe, Al 등 금속계 촉매가 주를 이루고 있다. 따라서 본 연구에서는 바이오가스의 정제효율을 높이기 위하여 CO₂ methanation 촉매를 다양한 조건에 따라 제조하였으며 각각의 촉매별 CO₂ 전환율을 평가하였다.

CO₂ 메탄화 반응을 위한 Ni 기반 Disk Type 촉매의 제조 최적화에 관한 연구

이재정 ( Jae-joung Lee ),문대헌 ( Dea-hyun Moon ),장순웅 ( Soon-wong Chang ) 한국환경과학회 2019 한국환경과학회지 Vol.28 No.1

The catalytic activity of Ni-0.2%YSZ (Yttria-Stabilized Zirconia) with different promoters was evaluated for CO₂ methanation. The catalysts were weighed for mixing and they were dried at 110 for molding into disks. The concentration of CO₂ and CH₄ for conducting of CO₂ methanation were analyzed by gas chromatography and the physical characteristics of the disk-type catalyst formed were analyzed by X-ray diffraction, scanning electron microscope and energy dispersive x-ray spectrometer. The addition of CeO₂ as a promoter for Ni-0.2%YSZ (denoted as Ni-5%Ce-0.2%YSZ) resulted in the highest CO₂ methanation. It also showed catalytic activity at a low temperature(200℃). Following this, ZrO₂, SiO₂, Al₂O₃ and TiO₂ were added to Ni-5%Ce-0.2%YSZ to compare the CO₂ methanation, and the highest efficiency was found for. Ni-1%Ti-5%Ce -0.2%YSZ Then, the concentration of Ti was increased to 10% and the catalytic activity was estimated using seven different types of commercial TiO₂. In conclusion, ST-01 TiO₂ showed the highest efficiency for CO₂ methanation.

수열 압력 제조 조건이 MoS2 촉매 특성과 직접 메탄화 반응에 미치는 영향

박정환,김성수,김진걸 한국수소및신에너지학회 2018 한국수소 및 신에너지학회논문집 Vol.29 No.2

After MoS2 catalyst was prepared at 1, 30, and 70 atm, the hydrothermal pressure effect over preparation of MoS2 was investigated in terms of catalyst characterization and direct methanation. Multifaceted characterization techniques such as XRD, BET, SEM, TPR, EDS, and XPS were used to analyze and investigate the effect of high pressure over the preparation of surface and bulk MoS2 catalyst. Result from XRD, SEM, and BET demonstrated that MoS2 was more dispersed as preparation pressure was increased, which resulted finer MoS2 crystal size and higher surface area. EDS result confirmed that bulk composition was MoS2 and XPS result showed that S/Mo mole ratio of surface was about 1.3. TPR showed that MoS2 prepared at 30 atm possessed higher active surface sites than MoS2 prepared at 1 atm and these sites could contribute to higher CO yield during methanation. Direct methanation was used to evaluate the CO conversion of the both catalysts prepared at 1 atm and 30 atm and reaction condition was at feed mole ratio of H2/CO=1, GHSV=4800, 30 atm, temperature(℃) of 300, 350, 400, and 450. MoS2 prepared at 30 atm showed more stable and higher CO conversion than MoS2 prepared at 1 atm. Faster deactivation was occurred over MoS2 prepared at 1 atm, which indicated that preparation pressure of MoS2 catalyst was the dominant factor to improve the yield of direct methanation.

탄소층으로 캡슐화된 Ni나노입자 촉매의 CO₂ 메탄화 반응

김혜정,김승보,김동현,윤재랑,김민재,전상구,이경자,이규복,Kim, Hye Jeong,Kim, Seung Bo,Kim, Dong Hyun,Youn, Jae-Rang,Kim, Min-Jae,Jeon, Sang Goo,Lee, Gyoung-Ja,Lee, Kyubock 한국재료학회 2021 한국재료학회지 Vol.31 No.9

Carbon-encapsulated Ni catalysts are synthesized by an electrical explosion of wires (EEW) method and applied for CO₂ methanation. We find that the presence of carbon shell on Ni nanoparticles as catalyst can positively affect CO₂ methanation reaction. Ni@5C that is produced under 5 % CH₄ partial pressure in Ar gas has highest conversions of 68 % at 350 ℃ and 70 % at 400 ℃, which are 73 and 75 % of the thermodynamic equilibrium conversion, respectively. The catalyst of Ni@10C with thicker carbon layer shows much reduced activity. The EEW-produced Ni catalysts with low specific surface area outperform Ni catalysts with high surface area synthesized by solution-based precipitation methods. Our finding in this study shows the possibility of utilizing carbon-encapsulated metal catalysts for heterogeneous catalysis reaction including CO₂ methanation. Furthermore, EEW, which is a highly promising method for massive production of metal nanoparticles, can be applied for various catalysis system, requiring scaled-up synthesis of catalysts.

A highly loaded NiΣiO₂ core-shell catalyst for CO methanation

Lakshmanan, P.,Kim, M.S.,Park, E.D. Elsevier 2016 Applied Catalysis A Vol.513 No.-

<P>The specific catalytic activity of a supported metal catalyst increases with an increase in the number of active sites per mass of catalyst, which can be accomplished by increasing the metal content and/or decreasing the particle size of the metal. However, this leads to sintering of metal particles during the reaction, especially in highly exothermic reactions such as CO methanation. In this study, we prepared different SiO2-supported Ni catalysts by wet impregnation and sol-gel methods, and applied them to CO methanation. The prepared catalysts were characterized with N-2 physisorption, X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), temperature-programmed reduction with H-2 (H-2-TPR), and transmission electron microscopy (TEM). Some problems associated with the wet impregnation method, such as sintering of Ni and the inability to load the silica with large amounts of Ni, were avoided by using the sol-gel method, in which size-controlled NiO was first synthesized using a polymer stabilizing agent, and then coated with a mesoporous silica shell through a polymerization approach. The prepared 55 wt% Ni@SiO2 catalyst exhibited the co-presence of Ni nanoparticles (mean size = 8.0 +/- 4.4 nm) and nanorods (mean length =15.5 +/- 13 nm, mean width = 8.1 +/- 4.4 nm). This catalyst was far superior for CO methanation than the conventional 33 wt% Ni/SiO2 catalyst prepared by wet impregnation, in which the Ni particle size was 24.5 nm. The 55 wt% Ni@SiO2 catalyst also exhibited excellent catalytic performance for selective CO methanation in the presence of an excessive amount of CO2. (C) 2015 Elsevier B.V. All rights reserved.</P>

가압 기포 유동층 반응기에서의 Ni계 촉매 CO₂ 메탄화 특성 연구

손성혜 ( Seong Hye Son ),서명원 ( Myung Won Seo ),황병욱 ( Byung Wook Hwang ),박성진 ( Sung Jin Park ),김정환 ( Jung Hwan Kim ),이도연 ( Do Yeon Lee ),고강석 ( Kang Seok Go ),전상구 ( Sang Goo Jeon ),윤성민 ( Sung Min Yoon ),김용 한국화학공학회 2018 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.56 No.6

Storing the surplus energy from renewable energy resource is one of the challenges related to intermittent and fluctuating nature of renewable energy electricity production. CO₂ methanation is well known reaction that as a renewable energy storage system. CO₂ methanation requires a catalyst to be active at relatively low temperatures (250-500℃) and selectivity towards methane. In this study, the catalytic performance test was conducted using a pressurized bubbling fluidized bed reactor (Diameter: 0.025 m and Height: 0.35 m) with Ni/γ-Al₂O₃ (Ni70%, and γ-Al₂O₃30%) catalyst. The range of the reaction conditions were H₂/CO₂ mole ratio range of 4.0-6.0, temperature of 300-420℃, pressure of 1-9 bar, and gas velocity (U₀/U_mf) of 1-5. As the H₂/CO₂ mole ratio, temperature and pressure increased, CO₂ conversion increases at the experimental temperature range. However, CO₂ conversion decreases with increasing gas velocity due to poor mixing characteristics in the fluidized bed. The maximum CO₂ conversion of 99.6% was obtained with the operating condition as follows; H₂/CO₂ ratio of 5, temperature of 400℃, pressure of 9 bar, and U₀/U_mf of 1.4-3.