High-Temperature CO2 Capture by Li4SiO4 Sorbents: Effect of CO2 Concentration and Cyclic Performance under Representative Conditions

Maria Teresa Izquierdo, Ahmed Saleh, Eva Sanchez Fernandez, M. Mercedes Maroto-Valer, Susana García

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Abstract

This study investigates CO2 capture on in-house-prepared Li4SiO4, a commercial Li4SiO4, and a commercial-derived CaO under the same experimental conditions in order to compare their performance with emphasis on the in-house-prepared Li4SiO4. The selected commercial Li4SiO4 was unsuitable for CO2 absorption-emission due to the insignificant CO2 uptake after regeneration. The commercial-derived CaO absorbs 41 wt %, which was the highest CO2 uptake among the studied samples. However, this sample underwent a severe decay after 12 carbonation-regeneration cycles despite the mild regeneration conditions used (700 °C under N2), reaching an almost constant CO2 uptake value (10 wt % after 18 cycles). The in-house-prepared Li4SiO4 absorbs 30 wt %, which was near the theoretical CO2 uptake for Li4SiO4. After an initial loss of CO2 uptake from near 30% to 26%, the performance of in-house-prepared Li4SiO4 was maintained after 16 cycles under the same conditions as those used for CaO. The effect of CO2 concentration on CO2 uptake was to obtain the inversion temperature for practical CO2 concentrations. Due to the significant differences among inversion temperatures from different equilibrium plots, experimental inversion temperatures were obtained by the temperature-programmed technique for absorption under a CO2 concentration of 4% and for emission under a CO2 concentration of 70%, giving 525 and 660 °C, respectively. A cyclic test was conducted with in-house-prepared Li4SiO4: absorption at 520 °C under a CO2 concentration of 4% and regeneration at 675 °C under a CO2 concentration of 70%. Under these mild thermal conditions the sample did not exhibit a CO2 uptake decay, indicating that this sorbent could be efficiently used for high-temperature CO2 capture from power plant flue gas.

Original languageEnglish
Pages (from-to)13802–13810
Number of pages9
JournalIndustrial and Engineering Chemistry Research
Volume57
Issue number41
Early online date25 Sep 2018
DOIs
Publication statusPublished - 17 Oct 2018

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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