초록 |
Among the various absorbents, MgO is a candidate of intermediate-temperature CO2 absorbent because the decomposition temperature (400 ℃) of its carbonate form is fitted with intermediate-temperature range. But it shows low reactivity with CO2 because of its high lattice energy. In order to enhance the reactivity of MgO with CO2, MgO promoted by alkali metal nitrates has been studied by some researchers. However, these absorbents show bad CO2 absorption and desorption cycle durability. So, the absorbent that has high cycle durability is needed to be investigated. Here, Na2CO3 or K2CO3 promoted MgO was studied. Na2CO3-promoted MgO shows stable CO2 absorption and desorption cycle durability. But this absorbent shows low CO2 desorption kinetics. On the contrary, K2CO3-promoted MgO shows bad cycle durability. But CO2 absorption and desorption kinetics of this absorbent are faster than that of Na2CO3-promoted MgO. In order to improve CO2 absorption and desorption properties of the absorbents, Na2-xKxCO3-promoted MgO with variation of the x-values is synthesized and its cycle durability was estimated. As a result, this absorbent shows good CO2 absorption and desorption cycle durability and kinetics. |