Effect of steam addition during calcination on CO2 capture performance and strength of bio-templated Ca-based pellets

Abstract

Enormous efforts have been devoted to improving the cyclic reactivity of the Ca-based sorbent for cyclic CO2 capture. Steam reactivation is one of the most promising technologies to regenerate the CO2 capture performance of the Ca-based sorbent remarkably. However, the strength of the pellets during the steam reactivation process is insufficiently investigated. This study examined the influences of steam addition during calcination on the CO2 capture capacity and mechanical strength of the bio-templated sorbent over multiple carbonation-calcination cycles. A CO2 uptake of 0.31 g/g was achieved after 20 cycles by adding 30 % steam into the calcination atmosphere, which is 2.2 times higher than the cycles without steam injection. After the long-term test up to 100 cycles with 30 % steam in the calcination environment, a 6-fold increase in the average crushing force of the pellets was observed. The enhancement of the mechanical strength was attributed to the synergy effect of thermal sintering and atmosphere-induced sintering. Generally, steam addition during calcination demonstrated great potential in retaining CO2 capture capacity and improving the mechanical strength of the bio-templated sorbent.