10.1021/acs.energyfuels.7b03137.s001
Long Ji
Long
Ji
Hai Yu
Hai
Yu
Bing Yu
Bing
Yu
Ruijie Zhang
Ruijie
Zhang
David French
David
French
Mihaela Grigore
Mihaela
Grigore
Xiaolong Wang
Xiaolong
Wang
Zuliang Chen
Zuliang
Chen
Shuaifei Zhao
Shuaifei
Zhao
Insights into Carbonation Kinetics of Fly Ash from
Victorian Lignite for CO<sub>2</sub> Sequestration
American Chemical Society
2018
energy-dispersive X-ray spectroscopy
carbonation rate
magnesium contents exhibit
carbonation reaction
scanning electron microscope
sequestrate CO 2
CO 2 Sequestration Mineral carbonation
Hazelwood power plant
CO 2 fixation capability
surface coverage model
carbonation efficiency
store CO 2
fly-ash particles
2018-01-08 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Insights_into_Carbonation_Kinetics_of_Fly_Ash_from_Victorian_Lignite_for_CO_sub_2_sub_Sequestration/5808498
Mineral
carbonation of fly ash can both capture and store CO<sub>2</sub> permanently
in a single process without long-term monitoring.
Previous studies indicate that fly ash with high calcium and magnesium
contents exhibit promising CO<sub>2</sub> fixation capability. However,
the reaction mechanisms and kinetics involved in the carbonation reaction
of fly ash is still not fully understood. In this study, a typical
Victorian brown coal fly ash from Hazelwood power plant was selected
to sequestrate CO<sub>2</sub> in a direct aqueous carbonation process.
Experiments were conducted in a vessel reactor at various temperatures
(40, 50, 60, and 70 °C), stirring rates (900, 1050, 1200, and
1350 rpm), and CO<sub>2</sub> pressures (3, 4, 5, 6, and 7 bar) to
investigate the reaction kinetics and identify the rate-limiting steps
of carbonation. The results show that both the carbonation rate and
the maximum carbonation efficiency could be improved by optimizing
parameters and by the introduction of NaHCO<sub>3</sub>. Also, the
complex effects of the operating parameters on the carbonation rate
and the maximum carbonation efficiency were investigated. The kinetic
data can be well fitted by the surface coverage model with the <i>R</i><sup>2</sup> ≥ 0.98, indicating that the carbonation
of fly ash can be physically expressed by this model. The maximum
carbonation efficiency of fly ash could also be well-predicted by
the model. In addition, the assumed mechanisms of the carbonation
reaction were validated by particle size, surface area, and porosity
changes of the fly-ash particles after carbonation reactions. The
observation of scanning electron microscope equipped with energy-dispersive
X-ray spectroscopy before and after carbonation also confirmed that
the newly formed precipitates were not only deposited on the active
surface but also filled the pores of the fly-ash particles.