Surface and bulk carbonate formation in calcium oxide during CO2 capture

Greg A Mutch, James A Anderson, David Vega-Maza* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)
26 Downloads (Pure)

Abstract

Calcium looping (CaL), the cyclic carbonation and calcination of limestone, is a prominent carbon capture option considering reduced parasitic energy consumption compared to amine scrubbing. The main issue preventing application is sorbent performance decay during cycling. Therefore hydration and extended carbonation reactivation strategies, as well as synthetic approaches to enhance or sustain reactivity, are of interest. Results of an investigation are presented on the impact of reactivation strategies on carbonate formation through detailed study using in-situ infrared spectroscopy. Surface and bulk carbonate formation regimes were readily distinguished allowing the influence of temporal, hydration and thermodynamic conditions within each regime to be studied. Surface chemistry of CaO during two initial cycles was shown to change. Significantly, it was shown that the CaO surface produced from the calcination of Ca(OH)2 possessed more highly reactive sites compared to the surface produced from CaCO3. The presence of water enhanced bulk carbonate formation at 300 °C and influenced the complexation of surface carbonates during looping. The results are of interest in the CaL community, offering molecular scale explanations for macroscale observations, whilst also informing on the role of humidity in direct air capture and sorption enhanced reaction processes.
Original languageEnglish
Pages (from-to)365-376
Number of pages12
JournalApplied Energy
Volume202
Early online date1 Jun 2017
DOIs
Publication statusPublished - 15 Sept 2017

Bibliographical note

The Engineering and Physical Sciences Research Council (EPSRC) is gratefully acknowledged for a Doctoral Training Grant for G.A.M. (EP/K0502960/1). Mr. C. McRitchie (Surface Chemistry and Catalysis Group, University of Aberdeen) is thanked for useful discussion.

Keywords

  • calcium looping
  • surface chemistry
  • in-situ infrared spectroscopy
  • carbon capture, utilisation and storage (CCUS)
  • carbonate formation
  • hydration

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