(514c) Capture and Methanation of CO2 Using Sodium Promoted MgO Based Catalytic Sorbent

A combined cycle of capture and conversion of CO₂ performed under isothermal conditions may be an advantageous process intensification approach compared to traditional CO₂ capture and sequestration in that the combined cycle can remove energy intensive temperature or pressure swing steps and minimize process units.¹ Furthermore, the produced fuel source from conversion of CO₂ can be directly used again as an energy source for power generation. A first generation of catalytic sorbents, such as Ru+CaO/Al₂O₃, for such an application has previously been reported.^1,2 In this work, sodium promoted MgO and loaded with ruthenium metal was used for capture and methanation of CO₂ in a combined cycle. The MgO support with various NaNO₃ and NaNO₂ promoter loadings was tested for CO₂ capture at 250 °C. MgO_NaNO₃ (1:0.1 molar ratio) showed adsorption capacity of 7.6 mmol CO₂/g in 12 h. MgO_NaNO₃_NaNO₂ (1:0.1:0.1 molar ratio) showed adsorption capacity of 8.6 mmol CO₂/g in 12 h. To evaluate performance of these materials in a capture and methanation cycle, the methanation capacity, which is equivalent to number of moles of methane produced per mass of catalytic sorbents in a cycle of capture and methanation, was measured for the prepared catalytic sorbents. It was found that a physical mixture of MgO_NaNO₃ and Ru supported MgO showed the highest methanation capacity at 250 °C with 1.1 mmol CH₄/g. This methanation capacity is comparable to the highest methanation capacity reported up to date, making sodium promoted MgO sorbent promising materials for such applications.

Reference:

(1) Duyar, M. S.; Treviño, M. A. A.; Farrauto, R. J. Dual Function Materials for CO₂ Capture and Conversion Using Renewable H₂. Appl. Catal. B Environ. 2015, 168–169, 370–376.

(2) Duyar, M. S.; Wang, S.; Arellano-Treviño, M. A.; Farrauto, R. J. CO₂ Utilization with a Novel Dual Function Material (DFM) for Capture and Catalytic Conversion to Synthetic Natural Gas: An Update. J. CO₂ Util. 2016, 15, 65–71.