CO2 green technologies in CO2 capture and direct utilization processes: methanation, reverse water-gas shift, and dry reforming of methane

Abstract

CO₂ green technologies, such as methanation, reverse water-gas shift (rWGS), and dry reforming of methane (DRM), in CO₂ capture and direct utilization processes are proposed to reduce the total thermal energy by effectively combining CO₂ capture and conversion using Ni/CaO catal-sorbents. Compared to conventional calcium looping using CaO-based sorbents, carbonated Ni/CaO catal-sorbents are completely regenerated at lower temperatures by simultaneously converting the captured CO₂ into chemicals via methanation, rWGS, or DRM. At optimum temperatures and concentrations of the feed gas (H₂ or CH₄), the Ni/CaO catal-sorbents show excellent CO₂ capture capacity and productivity. In addition, the structural variation of the Ni/CaO catal-sorbents is elucidated. Based on these theoretical and experimental studies, the novel integrated CO₂ capture and direct utilization processes can be a promising technology to produce chemicals as well as mitigate CO₂ levels from large-scale sources.