Carbon dioxide reforming of methane over MgO-promoted Ni/SiO2 catalysts with tunable Ni particle size

Ni-C/SiO2 and Ni-G/SiO2 catalysts were prepared by a complexed-impregnation method using citric acid and glycine as complexing agents, respectively. Ni/SiO2 was also prepared by the conventional incipient impregnation method. All the catalysts were comparatively tested for carbon dioxide reforming of methane (CDR) at P = 1.0 atm, T = 750 °C, CO2/CH4 = 1.0, and GHSV = 60,000 mL·g−1·h−1. The results showed that Ni-C/SiO2 and Ni-G/SiO2 exhibited better CDR performance, especially regarding stability, than Ni/SiO2. The conversions of CH4 and CO2 were kept constant above 82% and 87% after 20 h of reaction over Ni-C/SiO2 and Ni-G/SiO2 while they were decreased from 81% and 88% to 56% and 59%, respectively, over the Ni/SiO2. The characterization results of the catalysts before and after the reaction showed that the particle size and the distribution of Ni, as well as the interactions between Ni and the support were significantly influenced by the preparation method. As a result, an excellent resistance to the coking deposition and the anti-sintering of Ni was obtained over the Ni-C/SiO2 and Ni-G/SiO2, leading to a highly active and stable CDR performance.

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The Effect of Preparation Method of Ni-Supported SiO2 Catalysts for Carbon Dioxide Reforming of Methane

Catalysts ◽

10.3390/catal11101221 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1221

Author(s):

Hua-Ping Ren ◽

Si-Yi Ding ◽

Qiang Ma ◽

Wen-Qi Song ◽

Yu-Zhen Zhao ◽

...

Keyword(s):

Carbon Dioxide ◽

Particle Size ◽

Active Sites ◽

High Performance ◽

Preparation Method ◽

Complexing Agent ◽

Preparation Process ◽

Carbon Dioxide Reforming ◽

Preparation Methods ◽

Synthetic Strategy

Reforming methane to produce syngas is a subject that generates considerable interest. The process requires catalysts that possess high-performance active sites to activate stable C–H bonds. Herein, we report a facile synthetic strategy to prepare Ni-based catalysts by complexation–impregnation (Ni-G/SiO2-C) and precipitation–impregnation (Ni-G/SiO2-P) methods using glycine as a complexing agent. The particle size of Ni in both types of catalysts is decreased by adding glycine in the preparation process. Nevertheless, the preparation methods and amount of glycine play a significant role in the particle size and distribution of Ni over the Ni-based catalysts. The smaller particle size and narrower distribution of Ni were obtained in the Ni-G/SiO2-P catalyst. The catalysts were comparatively tested for carbon-dioxide reforming of methane (CDR). Ni-G/SiO2-P showed better CDR performance than Ni-G/SiO2-C and Ni/SiO2 and increased stability because of the smaller particle size and narrower distribution of Ni. Moreover, a high-performance Ni-based catalyst was prepared by optimizing the amount of glycine added. An unobservable deactivation was obtained over Ni-G-2/SiO2-P and Ni-G-3/SiO2-P for CDR during TOS = 20 h. Thus, a new promising method is described for the preparation of Ni-based catalysts for CDR.

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Synthesis gas production from carbon dioxide reforming of methane over Ni-MgO catalyst: Combined effects of titration rate during co-precipitation and CeO2 addition

Fuel Processing Technology ◽

10.1016/j.fuproc.2021.106877 ◽

2021 ◽

Vol 219 ◽

pp. 106877

Author(s):

Kyung-Won Jeon ◽

Hak-Min Kim ◽

Beom-Jun Kim ◽

Yeol-Lim Lee ◽

Hyun-Suk Na ◽

...

Keyword(s):

Carbon Dioxide ◽

Synthesis Gas ◽

Gas Production ◽

Combined Effects ◽

Carbon Dioxide Reforming ◽

Co Precipitation

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Influencing Factors of the Mineral Carbonation Process of Iron Ore Mining Waste in Sequestering Atmospheric Carbon Dioxide

Sustainability ◽

10.3390/su13041866 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1866

Author(s):

Noor Allesya Alis Ramli ◽

Faradiella Mohd Kusin ◽

Verma Loretta M. Molahid

Keyword(s):

Carbon Dioxide ◽

Particle Size ◽

Chemical Composition ◽

Iron Ore ◽

Divalent Cations ◽

Mining Industry ◽

Mining Waste ◽

Aluminum Silicate ◽

Mineral Carbonation ◽

Carbonation Process

Mining waste may contain potential minerals that can act as essential feedstock for long-term carbon sequestration through a mineral carbonation process. This study attempts to identify the mineralogical and chemical composition of iron ore mining waste alongside the effects of particle size, temperature, and pH on carbonation efficiency. The samples were found to be alkaline in nature (pH of 6.9–7.5) and contained small-sized particles of clay and silt, thus indicating their suitability for mineral carbonation reactions. Samples were composed of important silicate minerals needed for the formation of carbonates such as wollastonite, anorthite, diopside, perovskite, johannsenite, and magnesium aluminum silicate, and the Fe-bearing mineral magnetite. The presence of Fe2O3 (39.6–62.9%) and CaO (7.2–15.2%) indicated the potential of the waste to sequester carbon dioxide because these oxides are important divalent cations for mineral carbonation. The use of small-sized mine-waste particles enables the enhancement of carbonation efficiency, i.e., particles of <38 µm showed a greater extent of Fe and Ca carbonation efficiency (between 1.6–6.7%) compared to particles of <63 µm (0.9–5.7%) and 75 µm (0.7–6.0%). Increasing the reaction temperature from 80 °C to 150–200 °C resulted in a higher Fe and Ca carbonation efficiency of some samples between 0.9–5.8% and 0.8–4.0%, respectively. The effect of increasing the pH from 8–12 was notably observed in Fe carbonation efficiency of between 0.7–5.9% (pH 12) compared to 0.6–3.3% (pH 8). Ca carbonation efficiency was moderately observed (0.7–5.5%) as with the increasing pH between 8–10. Therefore, it has been evidenced that mineralogical and chemical composition were of great importance for the mineral carbonation process, and that the effects of particle size, pH, and temperature of iron mining waste were influential in determining carbonation efficiency. Findings would be beneficial for sustaining the mining industry while taking into account the issue of waste production in tackling the global carbon emission concerns.

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