Multi-stage structured catalyst system for post-treatment of GHGs emitted from industrial processes

Abstract

This study proposes a new approach for reducing CO₂ emissions from industrial processes and contributing to sustainable environmental development. The primary focus is on post-processing emitted CO₂ and constructing a coupled catalytic reaction system for CO₂ conversion. This coupled reaction system consists of three reactors: the 1st reactor for the methanation of CO₂, the 2nd reactor for the dry reforming of CH₄ (DRM), and the 3rd reactor for solid carbon capture. The constructed system enabled the continuous production of synthesis gas (H₂ + CO) even at a higher gas flow rate of 2 L min⁻¹ while recovering >30% of the introduced CO₂ as solid carbon. Furthermore, in this system, we have demonstrated that the quantity of H₂ lower than the stoichiometric ratio of the methanation reaction (H₂/CO₂ = 4.0) is advantageous for system operation. Significantly improved DRM and carbon capture performance were achieved under these conditions. The obtained results indicate the potential of this system in the efficient treatment of CO₂ from industrial emissions using a lower stoichiometric ratio of H₂, which has significant implications for environmental conservation and energy reduction. Additionally, the thermodynamic evaluation indicated that reducing the amount of supplied H₂ should have a beneficial impact on the exergy efficiency of the reaction system. The captured carbon has elongated fiber-like morphology with potential utilization as a functional material. We expect that the coupled reaction system designed in this study can serve as an innovative technology, contributing towards realizing a carbon-neutral society.