Performance of Coal Fly Ash Stabilized, CaO-based Sorbents under Different Carbonation-Calcination Conditions

Feng Yan, Jianguo Jiang*, Kaimin Li, Sicong Tian, Ming Zhao, Xuejing Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

The rapid deactivation of CaO sorbents due to sintering currently presents a major barrier to calcium looping for CO2 capture. In this work, we report an easy method for synthesizing highly stable CaO-based sorbents through mechanical mixing of a calcium precursor and coal fly ash (solid waste from coal-fired plants). To investigate the stable performance of as-synthesized sorbents, the effects of calcium precursors and carbonation–calcination conditions were studied and discussed. The synthetic sorbent derived from calcium oxalate (90%CaC2O4-FA-2h) showed the best performance and demonstrated a CO2 uptake of 0.38 g(CO2) g(CaO)−1 after 30 cycles. Even under the most severe calcination condition (at 920 °C in pure CO2), this sorbent maintained a stable capture capacity, with a final CO2 uptake of 0.27 g(CO2) g(CaO)−1 and an average decay rate of only 0.29% per cycle. Characterization of the sorbents confirmed that the formation of dispersed inert phase (gehlenite, Ca2Al2SiO7) was responsible for this high cyclic CO2 uptake and strong sintering resistance. This strategy significantly enhances the high temperature stability of CaO-based sorbents through in situ reuse of coal fly ash, and is thus an effective approach to CO2 capture from the large point source.

Original languageEnglish
Pages (from-to)2092-2099
Number of pages8
JournalACS Sustainable Chemistry and Engineering
Volume3
Issue number9
DOIs
Publication statusPublished - 8 Sep 2015
Externally publishedYes

Keywords

  • CO₂ capture
  • Calcium looping
  • Coal fly ash
  • Calcium precursor
  • Sintering resistance

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