Solid-state decomposition of Ca2CuO3 enhances its CO2 reactivity and cycle stability. (15th January 2023)

• Record Type: Journal Article
• Authors: Hassani, Ehsan; Feyzbar-Khalkhali-Nejad, Farshad; Rashti, Ali; Oh, Tae-Sik
• Is Part Of: Fuel. Volume 332(2023)Part 2
• Publication Date: 2023-01-15
• Subjects: Decomposition -- Post-combustion CO2 capture -- Composite -- Thermal conductivity; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.126160
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: Ca2 CuO3 sorbent was decomposed by thermal reduction. Sorbent conversion was calculated from X-ray diffraction under operating conditions. In situ generated copper particles enhanced sorbent performance. High thermal conductivity of the decomposed sorbent suppressed sintering. Abstract: We evaluated the carbonation/decarbonation performance of Ca2 CuO3 sorbents with different degrees of reductive decomposition for post-combustion CO2 capture. Three sorbents, non-decomposed ( N -CCO), partially decomposed (P-CCO), and fully decomposed (F-CCO) Ca2 CuO3 were tested. We found a higher CO2 capacity with a high content of in situ generated copper. Through temperature-resolved in situ X-ray diffraction, we confirmed that F-CCO started to form calcium carbonate at lower temperatures (∼400 °C) than N -CCO, which does not react with CO2 until 600 °C. F-CCO demonstrated faster regeneration kinetics as well. At 600 °C, a significant recovery of 85 % was achieved for F-CCO compared to 16 % for N -CCO. F-CCO also showed a higher degree of carbonation than P-CCO and N -CCO under isothermal carbonation/decarbonation at 800 °C. The conversion of F-CCO reached 52 % after just 26 min, while the conversion was only 46 % for P-CCO and 48 % for N -CCO even after the longer reaction time of 39 min. The F-CCO sorbent showed an extremely high regeneration rate at 800 °C compared to the other sorbents. The regeneration of F-CCO was completed in less than 3.5 min. By contrast, the full regeneration of other sorbents did not take place even after 26 min (95 % recovery for P-CCO and 78 % recovery for N -CCO). Finally, when regenerated under 4 % H2 in N2, the sorbents' average conversion over ten cycles was estimated at 79.2 %, 44.7 %, and 45.5 % for F-CCO, P-CCO, and CaO. The high thermal conductivity of copper particles is attributed to the efficient performance of F-CCO.