Reuse of fly ash from a fluidized bed combustor for sulfur uptake: the role of ettringite in hydration-induced reactivation

Journal Article · Sat Oct 01 04:00:00 EDT 2005 · Energy and Fuels

DOI:https://doi.org/10.1021/ef049676w· OSTI ID:20674537

Montagnaro, Fabio; Salatino, Piero; Bernardo, Graziella; Telesca, Antonio; Valenti, Gian Lorenzo ^[1]

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1. Universita degli Studi di Napoli Federico II, Napoli (Italy). Dipartimento di Chimica

This study addresses the effectiveness of hydration-induced reactivation of fly ash from an industrial FBC to produce a sorbent suitable for further SO{sub 2} uptake during fluidized bed combustion. Ash reactivation was accomplished by water hydration at 70{sup o}C for 48 h. Maximum extent and rate of SO{sub 2} sorption as well as attrition/fragmentation behavior of the reactivated ash were assessed. Testing of sulfur sorption capacity was carried out at 850{sup o}C for 100 min in a laboratory-scale fluidized bed reactor under simulated combustion/desulfurization conditions. Characterization of the tested materials was based on X-ray diffraction and simultaneous differential thermal/thermogravimetric analyses. It was found that ettringite was extensively produced during water hydration and that effective enhancement of the sulfur uptake ability of the fly ash was achieved. The conversion degree of calcium to CaSO{sub 4} of the reactivated ash was as high as 92%. The very favorable performance of reactivated ash as a sulfur sorbent was mostly related to the large amount of free lime formed during thermal decomposition of ettringite. Compared with other sorbent materials, the reactivated ash material was characterized by a rather large attrition rate. 25 refs., 8 figs., 2 tabs.

• OSTI ID: 20674537
• Journal Information: Energy and Fuels, Journal Name: Energy and Fuels Journal Issue: 5 Vol. 19; ISSN ENFUEM; ISSN 0887-0624
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ADSORBENTS
CHEMICAL ACTIVATION
FLUIDIZED-BED COMBUSTORS
FLY ASH
HYDRATION
SORPTIVE PROPERTIES
SULFUR DIOXIDE
WASTE PRODUCT UTILIZATION