TY - JOUR
T1 - Sintering of calcium oxide (CaO) during CO 2 chemisorption
T2 - A reactive molecular dynamics study
AU - Zhang, Luzheng
AU - Lu, Yongqi
AU - Rostam-Abadi, Massoud
PY - 2012/12/28
Y1 - 2012/12/28
N2 - Reactive dynamics simulations with the reactive force field (ReaxFF) were performed in NVE ensembles to study the sintering of two solid calcium oxide (CaO) particles with and without CO 2 chemisorption. The simulated sintering conditions included starting adsorption temperatures at 1000 K and 1500 K and particle separation distances of 0.3 and 0.5 nm. The results revealed that the expansion of sorbent particles during CO 2 chemisorption was attributed to the sintering of two CaO-CaO particles. Increasing the adsorption temperature resulted in more particle expansion and sintering. The shorter the distance between two particles, the faster the rate of sintering during CO 2 adsorption. A detailed analysis on atom spatial variations revealed that the sorbent particles with a larger separation distance had a larger CO 2 uptake because of less sintering incurred. The chemisorptions of CO 2 on CaO particles sintered at high adsorption temperatures were also simulated to mimic the process of sorbent regeneration. It was found that regeneration would be more difficult for sintered particles than for fresh particles. In addition, a possible sintering barrier, magnesium oxide (MgO), was introduced to prevent CaO particles from sintering during CO 2 chemisorption. It was found that the MgO particles could reduce the sintering of CaO particles during CO 2 chemisorption. Simulation results from this study provided some guidelines on synthesizing or selecting sorbents with less sintering effect for multiple CO 2 adsorption-regeneration cycles.
AB - Reactive dynamics simulations with the reactive force field (ReaxFF) were performed in NVE ensembles to study the sintering of two solid calcium oxide (CaO) particles with and without CO 2 chemisorption. The simulated sintering conditions included starting adsorption temperatures at 1000 K and 1500 K and particle separation distances of 0.3 and 0.5 nm. The results revealed that the expansion of sorbent particles during CO 2 chemisorption was attributed to the sintering of two CaO-CaO particles. Increasing the adsorption temperature resulted in more particle expansion and sintering. The shorter the distance between two particles, the faster the rate of sintering during CO 2 adsorption. A detailed analysis on atom spatial variations revealed that the sorbent particles with a larger separation distance had a larger CO 2 uptake because of less sintering incurred. The chemisorptions of CO 2 on CaO particles sintered at high adsorption temperatures were also simulated to mimic the process of sorbent regeneration. It was found that regeneration would be more difficult for sintered particles than for fresh particles. In addition, a possible sintering barrier, magnesium oxide (MgO), was introduced to prevent CaO particles from sintering during CO 2 chemisorption. It was found that the MgO particles could reduce the sintering of CaO particles during CO 2 chemisorption. Simulation results from this study provided some guidelines on synthesizing or selecting sorbents with less sintering effect for multiple CO 2 adsorption-regeneration cycles.
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U2 - 10.1039/c2cp42209c
DO - 10.1039/c2cp42209c
M3 - Article
C2 - 22990764
AN - SCOPUS:84870184445
SN - 1463-9076
VL - 14
SP - 16633
EP - 16643
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 48
ER -