Impact of SO2in the Presence of Steam on Carbonation and Sulfation of Calcium Sorbents

CO2 Capture at Medium to High Temperature Using Solid Oxide-Based Sorbents: Fundamental Aspects, Mechanistic Insights, and Recent Advances

Carbon dioxide capture and mitigation form a key part of the technological response to combat climate change and reduce CO₂ emissions. Solid materials capable of reversibly absorbing CO₂ have been the focus of intense research for the past two decades, with promising stability and low energy costs to implement and operate compared to the more widely used liquid amines. In this review, we explore the fundamental aspects underpinning solid CO₂ sorbents based on alkali and alkaline earth metal oxides operating at medium to high temperature: how their structure, chemical composition, and morphology impact their performance and long-term use. Various optimization strategies are outlined to improve upon the most promising materials, and we combine recent advances across disparate scientific disciplines, including materials discovery, synthesis, and in situ characterization, to present a coherent understanding of the mechanisms of CO₂ absorption both at surfaces and within solid materials.

Calcium Looping: On the Positive Influence of SO2 and the Negative Influence of H2O on CO2 Capture by Metamorphosed Limestone-Derived Sorbents

The CO₂ capture performance of sorbents derived from three distinct limestones, including a metamorphosed limestone, is studied under conditions relevant for calcium looping CO₂ capture from power plant flue gas. The combined and individual influence of flue gas H₂O and SO₂ content, the influence of textural changes caused by sequential calcination/carbonation cycles, and the impact of CaSO₄ accumulation on the sorbents' capture performance were examined using bubbling fluidized bed reactor systems. The metamorphosed limestone-derived sorbents exhibit atypical capture behavior: flue gas H₂O negatively influences CO₂ capture performance, while limited sulfation can positively influence CO₂ capture, with space time significantly impacting CO₂ and SO₂ co-capture performance. The morphological characteristics influencing sorbents' capture behavior were examined using imaging and material characterization tools, and a detailed discussion is presented. This insight into the morphology responsible for metamorphosed limestone-derived sorbent's anomalous capture behavior can guide future sorbent selection and design efforts.