scholarly journals Experimental Study on CO2 Methanation over Ni/Al2O3, Ru/Al2O3, and Ru-Ni/Al2O3 Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1112 ◽  
Author(s):  
Rei-Yu Chein ◽  
Chih-Chang Wang
Keyword(s):  
Space Velocity ◽  
Molar Ratio ◽  
Ni Catalyst ◽  
Co2 Conversion ◽  
Co2 Methanation ◽  
Temperature Changes ◽  
Good Thermal Stability ◽  
Reverse Water Gas Shift ◽  
Optimum Reaction ◽  
Shift Reaction

CO2 methanation is recognized as one of the best technologies for storing intermittent renewable energy in the form of CH4. In this study, CO2 methanation performance is investigated using Ni/Al2O3, Ru/Al2O3, and Ru-Ni/Al2O3 as the catalysts under conditions of atmospheric pressure, a molar ratio of H2/CO2 = 5, and a space velocity of 5835 h−1. For reaction temperatures ranging from 250 to 550 °C, it was found that the optimum reaction temperature is 400 °C for all catalysts studied. At this temperature, the maximum values of CO2 conversion, H2 efficiency, and CH4 yield and lowest CO yield can be obtained. With temperatures higher than 400 °C, reverse CO2 methanation results in CO2 conversion and CH4 yield decreases with increased temperature, while CO is formed due to reverse water-gas shift reaction. The experimental results showed that CO2 methanation performance at low temperatures can be enhanced greatly using the bimetallic Ru-Ni catalyst compared with the monometallic Ru or Ni catalyst. Under ascending-descending temperature changes between 250 °C and 550 °C, good thermal stability is obtained from Ru-Ni/Al2O3 catalyst. About a 3% decrease in CO2 conversion is found after three continuous cycles (74 h) test.

scholarly journals CO2 Methanation of Biogas over 20 wt% Ni-Mg-Al Catalyst: on the Effect of N2, CH4, and O2 on CO2 Conversion Rate

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1201
Author(s):  
Danbee Han ◽  
Yunji Kim ◽  
Hyunseung Byun ◽  
Wonjun Cho ◽  
Youngsoon Baek
Keyword(s):  
Reaction Temperature ◽  
Photoelectron Spectroscopy ◽  
Conversion Rate ◽  
Space Velocity ◽  
Molar Ratio ◽  
Co2 Conversion ◽  
X Ray Diffraction ◽  
Co2 Methanation ◽  
X Ray ◽  
Ch4 Production

Biogas contains more than 40% CO2 that can be removed to produce high quality CH4. Recently, CH4 production from CO2 methanation has been reported in several studies. In this study, CO2 methanation of biogas was performed over a 20 wt% Ni-Mg-Al catalyst, and the effects of CO2 conversion rate and CH4 selectivity were investigated as a function of CH4, O2, H2O, and N2 compositions of the biogas. At a gas hourly space velocity (GHSV) of 30,000 h−1, the CO2 conversion rate was ~79.3% with a CH4 selectivity of 95%. In addition, the effects of the reaction temperature (200–450 °C), GHSV (21,000–50,000 h−1), and H2/CO2 molar ratio (3–5) on the CO2 conversion rate and CH4 selectivity over the 20 wt% Ni-Mg-Al catalyst were evaluated. The characteristics of the catalyst were analyzed using Brunauer–Emmett–Teller surface area analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The catalyst was stable for approximately 200 h at a GHSV of 30,000 h−1 and a reaction temperature of 350 °C. CO2 conversion and CH4 selectivity were maintained at 75% and 93%, respectively, and the catalyst was therefore concluded to exhibit stable activity.

scholarly journals CO2 Methanation of Biogas Over 20 wt% Ni-Mg-Al Catalyst: On the Effect of N2, CH4, and O2 on CO2 Conversion Rate

2020 ◽  
Author(s):  
Danbee Han ◽  
Yunji Kim ◽  
Hyunseung Byun ◽  
Wonjun Cho ◽  
Youngsoon Baek
Keyword(s):  
Reaction Temperature ◽  
Photoelectron Spectroscopy ◽  
Conversion Rate ◽  
Space Velocity ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Co2 Conversion ◽  
Co2 Methanation ◽  
X Ray ◽  
Ch4 Production

Biogas contains more than 40% CO2 that can be removed to produce high quality CH4. Recently, CH4 production from CO2 methanation has been reported in several studies. In this study, CO2 methanation of biogas was performed over a 20 wt% Ni-Mg-Al catalyst, and the effects of CO2 conversion rate and CH4 selectivity were investigated as a function of CH4, O2, H2O, and N2 compositions of the biogas. At a gas hourly space velocity (GHSV) of 30,000/h, the CO2 conversion rate was ~79.3% with a CH4 selectivity of 95%. In addition, the effects of the reaction temperature (200–450 °C), GHSV (21,000–50,000/h), and H2/CO2 molar ratio (3–5) on the CO2 conversion rate and CH4 selectivity over the 20 wt% Ni-Mg-Al catalyst were evaluated. The characteristics of the catalyst were analyzed using Brunauer-Emmett-Teller (BET) surface area analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The catalyst was stable for approximately 200 h at a GHSV of 30,000/h and a reaction temperature of 350 °C. CO2 conversion and CH4 selectivity were maintained at 75% and 93%, respectively, and the catalyst was therefore concluded to exhibit stable activity.

CO2 methanation and reverse water gas shift reaction. Kinetic study based on in situ spatially-resolved measurements

2020 ◽  
Vol 390 ◽  
pp. 124629 ◽  
Author(s):  
Jose A. Hernandez Lalinde ◽  
Pakpong Roongruangsree ◽  
Jan Ilsemann ◽  
Marcus Bäumer ◽  
Jan Kopyscinski
Keyword(s):  
Kinetic Study ◽  
Reaction Kinetic ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Co2 Methanation ◽  
Spatially Resolved ◽  
Reverse Water Gas Shift ◽  
Shift Reaction ◽  
Water Gas

Pt/UiO-66 Nanocomposites as Catalysts for CO2 Methanation Process

2019 ◽  
Vol 19 (6) ◽  
pp. 3187-3196 ◽  
Author(s):  
Maria Mihet ◽  
Gabriela Blanita ◽  
Monica Dan ◽  
Lucian Barbu-Tudoran ◽  
Mihaela D Lazar
Keyword(s):  
Thermal Stability ◽  
Surface Area ◽  
Metal Organic Framework ◽  
Catalytic Performance ◽  
Molar Ratio ◽  
High Dispersion ◽  
Co2 Methanation ◽  
Preparation Methods ◽  
Good Thermal Stability ◽  
Catalytic Support

Pt/UiO-66 nanocomposites with platinum target concentration of 3 wt.% were prepared by 3 preparation methods, characterized and tested in the CO2 methanation process. Choice of the microporous UiO-66 metal-organic framework (Zr6O4(OH)4 with 1,4-benzene-dicarboxylate ligand) as catalytic support was motivated by the CO2 chemisorption capacity (proven by CO2-TPD profiles), large specific surface area (1477 m2/g) which favors a high dispersion of metal nanoparticles and good thermal stability. The preparation methods for the Pt/UiO-66 nanocomposites are: (1) wetimpregnation followed by reduction in H2 at 200 °C for 2 h; (2) wet-impregnation followed by reduction with an aqueous solution of NaBH4; and (3) “double-solvent” method, followed by reduction with NaBH4. The UiO-66 based nanocomposites were characterized by N2 adsorption–desorption (BET method), XRD, and SEM/TEM. The Pt/UiO-66 catalyst prepared by method 3 was chosen for catalytic testing due to its highest surface area, smallest platinum nanoparticles (PtNPs) size, the localization of PtNPs both on the grain’s internal and external surface and best thermal stability in the desired temperature range. Its capacity to adsorb and activate CO2 and H2 was evaluated in thermo-programmed desorption experiments (H2-TPD and CO2-TPD). Hydrogen is molecularly adsorbed, while CO2 is adsorbed both molecularly and dissociatively. The catalytic performance in the CO2 methanation process was evaluated by Temperature Programmed Reactions (TPRea, 2 °C/min, 30–350 °C), at atmospheric pressure. The best results were obtained at 350 °C, CO2:H2 molar ratio of 1:5.2 and GHSV ═ 1650 h−1. In these conditions CO2 conversion is almost 50% and CH4 selectivity is 36%, the rest of the converted CO2 being transformed in CO.

scholarly journals Optimization of Operating Conditions for CO2 Methanation Process Using Design of Experiments

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8414
Author(s):  
Chae-Eun Yeo ◽  
Minhye Seo ◽  
Dongju Kim ◽  
Cheonwoo Jeong ◽  
Hye-Sun Shin ◽  
...  
Keyword(s):  
Design Method ◽  
Space Velocity ◽  
Operating Conditions ◽  
Catalyst Characterization ◽  
Co2 Conversion ◽  
Optimal Operating ◽  
Co2 Methanation ◽  
Factors Affecting ◽  
Experimental Design Method

In this study, the Taguchi experimental design method using an L16 orthogonal array was attempted in order to investigate the optimal operating conditions for the CO2 methanation process in Ni-based catalysts. The relative influence of the main factors affecting CO2 conversion and CH4 yield was ranked as follows: reactor pressure > space velocity > reaction temperature. The optimal combination of operating conditions was a reactor temperature of 315 °C, a pressure of 19 bar, and a space velocity of 6000 h−1. The effect of the H2/CO2 ratio on CO2 conversion and CH4 yield was further considered under these optimal operating conditions. Moreover, the catalyst was characterized in order to investigate the production of coke through Brunauer–Emmett–Teller analysis, thermogravimetric analysis, and scanning electron microscopy. The amount of coke produced after the reaction for approximately 24 h was ~2 wt.%. Therefore, the desired CH4 yield and long-term operational stability were successfully obtained using the Taguchi design method and catalyst characterization.

The Reverse Water-Gas Shift Reaction and the Synthesis of Mixed Alcohols over K/Cu-Zn Catalyst from CO2 Hydrogenation

2013 ◽  
Vol 772 ◽  
pp. 275-280 ◽  
Author(s):  
Shang Gui Li ◽  
Hai Jun Guo ◽  
Hai Rong Zhang ◽  
Jun Luo ◽  
Lian Xiong ◽  
...  
Keyword(s):  
Space Velocity ◽  
Product Distribution ◽  
Water Gas Shift ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Reverse Water Gas Shift ◽  
Rwgs Reaction ◽  
Water Gas ◽  
Mixed Alcohols

The K/Cu-Zn catalyst has been synthesized by the co-precipitation method coupling with impregnation method and the catalytic performances for the reverse water gas shift (RWGS) reaction and mixed alcohols synthesis from CO2 hydrogenation have been investigated. The catalytic activity and product distribution depend strongly on reaction temperature, pressure, space velocity and the molar ratio of H2/CO2. These results indicated that the optimal conditions for CO2 hydrogenation over K/Cu-Zn catalyst were as follows: 350 K, 6.0 MPa, 5000 h-1 and H2/CO2 = 3.0, under which the selectivity of CO and mixed alcohols reach 84.27 wt% and 7.56 wt%, respectively. The outstanding performances for RWGS reaction and mixed alcohols synthesis of K/Cu-Zn catalyst can be due to the well dispersion of Cu active component.

The Preparation of Honeycomb Cordierite Mn-Ce/TiO2 Catalyst and Denitration Performance

2013 ◽  
Vol 744 ◽  
pp. 370-374 ◽  
Author(s):  
Ruo Han Li ◽  
Song Zhou
Keyword(s):  
Catalytic Reduction ◽  
Space Velocity ◽  
Ammonia Nitrogen ◽  
Molar Ratio ◽  
Scr Catalyst ◽  
Catalytic Activities ◽  
Cordierite Ceramic ◽  
Optimum Reaction ◽  
Nitrogen Ratio ◽  
Optimum Reaction Condition

SCR catalyst is the core of SCR technology. More attention to manganese oxide-based catalysts has been paid due to their excellent catalytic activities in low-temperature selective catalytic reduction of NOx by NH3 (NH3-SCR) in recent years. In this paper, the preparation method of honeycomb cordierite Mn-Ce/TiO2 catalyst and denitration performance is studied. Different amount of TiO2, Mn and Ce are supported on the cordierite ceramic and the SCR catalytic tests are conducted. In the tests, the influence of Mn/Ti molar ratio on the denitration performance and the effect of reaction temperature, inlet NO concentration, volumetric space velocity and ammonia nitrogen ratio on the denitration performance are found. The results show: (1) Mn/TiO2 catalyst has the highest catalytic activity when the Mn/Ti molar ratio is 0.4. (2) The optimum reaction condition of honeycomb cordierite Mn-Ce/TiO2 catalyst denitration reaction is the inlet NO concentration is 0.075%, volumetric space velocity is 4000 h 1 and ammonia nitrogen ratio is 1.05.

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