Porous spherical calcium-based sorbents prepared by a bamboo templating method for cyclic CO2 capture

Abstract

Calcium looping is regarded as one of the most promising technologies to capture CO2; however, calcium based sorbents experienced rapid decay in CO2 capture capacities and serious attrition during cyclic high temperature reactions; thus, it is critical to develop new calcium based sorbent with high CO2 capture capacity and high attrition resistance. This paper presents a new modeling approach with bamboo, a pore-creating agent templating, to enhance the CO2 capture and attrition resistance performance of the calcium based sorbents simultaneously. The cyclic CO2 capture performance were tested by a simultaneous thermal analyzer (STA), and the pore structure were analyzed by field emission scanning electron microscope (FSEM) and N2 absorption/desorption technologies. The bamboo powder was analyzed by pyrolysis, proximate analysis and elemental analysis method. A friability tester (FT) was used to investigate the mechanical strength of these modeled sorbents. The results show that all the bamboo templated sorbents behaved enhanced CO2 capture performances, especially the molded sorbents with 2 wt% mass ratio of bamboo templated (CaS-B2) showed the highest capture capacity of 0.262 g/g after 25 cycles, which was 33.7% higher than that of molded sorbents without bamboo templating (CaS). The modeling method is beneficial to prepare sorbents with favorable mechanical strength, and the optimum templating mass ratio is 2 wt% (lost a minority of 0.166 wt% during 20,000 turns, which was almost negligible comparing to 3.64 wt% of limestone).