ICCU-methanation using a vertical stainless steel tubular reactor

https://doi.org/10.1016/j.fuel.2022.123842

“CO₂ adsorption and hydrogenation cycles were carried out in a vertical stainless steel tubular reactor inside a 3-zone tube furnace. The reactor was filled with 1.0 g of pelletized (0.3–0.5 mm) fresh formulation, where the operating temperature was continuously measured through a thermocouple placed in the centre of the catalytic bed. Prior to the catalytic test, fresh samples were in-situ reduced with a stream composed of 10% H₂/Ar leading to the conformation of the final DFM due to the controlled reduction of perovskite-based formulation. With that aim, the temperature was progressively increased from room temperature to 650, 550 or 800 °C (2 h) for bulk and ceria- and alumina-supported samples, respectively. Note that the reduction temperature for each support was already optimized in a previous study [39].

Once the DFM was obtained, CO₂ adsorption and hydrogenation experiments were carried out, increasing the reaction temperature progressively from 280 to 520 °C, in steps of 40 °C. During the adsorption period (60 s), the feed composition was 10% CO₂/Ar. Then, this step was followed by a purge with Ar (120 s) to remove weakly adsorbed CO₂ and prevent mixing of streams. Finally, CO₂ was replaced by a 10% of H₂ during the hydrogenation (methanation) period (120 s). Before starting the following CO₂ adsorption period, the catalyst and the system were again purged with Ar for 60 s. The catalytic tests were carried out with a total flow rate of 1200 mL min⁻¹. This flow corresponds to space velocities of around 45,000 and 140,000 h⁻¹ for ceria- and alumina-supported samples, respectively. CO₂, CH₄, CO and H₂O were continuously quantified by a MKS MultiGas 2030 FT-IR analyser.”