Influence of calcination temperature on CO2 capture using tubular MgO and stability analysis

“The CO2 capture performance of the MgO sample was examined again, applying a higher calcination reaction temperature of 450 °C to obtain complete regeneration (referred to as MgO_HT). As shown in Fig. 3(a), the MgO_HT sample exhibited stable carbonation and complete regeneration compared to the MgO sample. However, the degree of carbonation decreased continuously for the given cycles. Note that MgO/CNT_Air stably maintained its carbonation–calcination reactivity for the given period, even at the lower calcination temperature of 400 °C.

The weight change profiles of the above sample were converted to the MgO conversion (XN) to MgCO3, as shown in Fig. 3(b). MgO conversion of MgO/CNT_Air abruptly decreased from 0.68 (X1) to 0.32 (X3), then gradually increased to 0.39 (X4) and 0.45 (X11). After that, the conversion was stabilized at ∼0.44 for the remaining cycles. The MgO sample similarly exhibited a steep decrement from 0.77 (X1) to 0.12 (X13). Then, the pattern stabilized with a low value of MgO conversion. On the other hand, MgO_HT exhibited a gradual decrease in MgO conversion from 0.58 (X2) to 0.32 (X30). Note that, starting from X15, MgO/CNT_Air showed MgO conversion higher than that of MgO_HT. The recyclability of MgO/CNT_Air was further examined for 100 cycles of carbonation–calcination (Fig. 4). The MgO conversion of MgO/CNT_Air steadily decreased from 0.32 (X66) to 0.26 (X100). The decaying patterns of both MgO/CNT_Air and MgO_HT were analyzed. The slopes were −0.0023 (XN/cycle) and −0.0095 (XN/cycle) for MgO/CNT_Air and MgO_HT, respectively. These results indicate that the inactivation tendency of MgO_HT was four times faster than in the case of MgO/CNT_Air, which implies that MgO/CNT_Air can achieve better durability even under mild regeneration conditions.”


Fig. 3 CO2 capture performance of MgO-based sorbents for 30 cycles of carbonation–dissociation measured by TG-DSC. (a) Normalized weight (wt%) profiles and (b) MgO conversion (XN). Weight profiles are normalized according to each weight of pristine MgO-based sorbents.”


Fig. 4 CO2 capture performance of MgO_HT (30 cycles) and MgO/CNT_Air (100 cycles) in MgO conversion (XN) by TG-DSC. Linear regressions of performance decay are given.”

Leave a Comment