1 research outputs found
The Role of Water during CO<sub>2</sub> Adsorption by Ca-Based Sorbents at High Temperature
Reactions
of CaO, MgO, and decarbonated dolomite (CaOMgO) with
CO<sub>2</sub> and added water have been studied with the goal of
understanding fundamental issues related to these materials’
performance as CO<sub>2</sub> sorbents. We used a fixed bed reactor,
in situ XRD, and DRIFTS to monitor the extent and kinetics of carbonation,
surface reactions, and performance loss during repetitive adsorption–desorption
cycles at industrial relevant conditions. From reactor and in situ
XRD experiments, we found that water is essential to reach high carbonation
levels (solid conversion >40%) of CaO and CaOMgO, which is in contrast
to a situation where only a small fraction (<10%) of the capacity
is used. Water has a more pronounced effect when applying CaOMgO as
sorbent as compared to CaO, both when considering solid conversions
and carbonation rates. DRIFTS shows that water together with CO<sub>2</sub> do in fact react at the MgO surface into carbonates species.
Furthermore, H<sub>2</sub>CO<sub>3</sub> may be important for exploiting
CaO and CaOMgO materials because hydrogen carbonate is observed as
a surface species only during reactions with water