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Preparation of CaO-based sorbent from coal fly ash cenospheres for calcium looping process

TitoloPreparation of CaO-based sorbent from coal fly ash cenospheres for calcium looping process
Tipo di pubblicazioneArticolo su Rivista peer-reviewed
Anno di Pubblicazione2019
AutoriScaccia, S., Vanga G., Mirabile Gattia Daniele, and Stendardo S.
RivistaJournal of Alloys and Compounds
Parole chiavealuminum hydroxide, Ashes, calcite, Calcium Carbonate, Calcium looping, Carbon dioxide, Citric acid, Coal, Coal Ash, Coal fired plants, Coal fly ash, Coal-fired power plant, Feldspar, Fly ash, Fossil fuel power plants, Gehlenite, High temperature, Hydrated lime, Mullite, Multiple cycles, Silica, Silicate minerals, Sorbents, Sorption, Supporting material

With the aim to synthesize an inexpensive and high-stable sorbent for CO2 capture processes, an industrial waste-product derived from coal-fired power plant, the so-called coal fly ash (CFA) cenospheres, was employed as inert supporting material. The CaO-based sorbent derived from CFA cenospheres (mainly composed of mullite and quartz) was prepared via a solution-based citric acid method. The obtained slurry was decomposed at 500 °C in air for 2 h. From the XRD results the CaO-CFA500 sorbent was mainly composed of Ca12Al14O33 (mayenite) and Ca(OH)2 along with trace of γ-Al(OH)3 and CaCO3 and starting SiO2. A further air-heating at 900 °C was conducted because the CO2 sorbent is submitted at high temperature for regeneration. The CaO-CFA900 sorbent was made of free-CaO and two crystalline calcium-alumino-silicate phases, namely gehlenite (Ca2Al2SiO7) and anorthite (CaAl2Si2O8). The optimized mesopore size particles belonging to CaO-CFA900 was reflected in a high stability over multiple cycles of carbonation/calcination. The initial CO2 capture capacity of the sorbent was 0.33 g CO2 g−1 sorbent, which was about three times the value of pure CaO (0.11 g CO2 g−1 CaO), and reduced to 0.22 g CO2 g−1 sorbent after 20 cycles remaining then stable over 200th cycles. From the present results it can be argued that CaL process could be easily scalable by re-using a coal-fired plant waste-product. © 2019 Elsevier B.V.


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Citation KeyScaccia2019123