Calcium-looping thermochemical energy storage and mechanical performance of bio-templated CaO-based pellets under steam-containing environments

Abstract

The calcium-looping thermochemical heat storage is recognized as a promising technology due to its affordable raw material expense, eco-friendliness, and superior heat storage and release capacity. To investigate the impact of inert support, pore-forming template, and reaction atmosphere on the cyclic thermochemical heat storage capacity and mechanical properties of calcium-based sorbent, spherical CaO-based pellets were prepared using cement as an inert support and microcrystalline cellulose, starch, and sesbania gum as pore-forming templates. The test results demonstrated that the optimal composition ratio for calcium-based particles was 5 wt% cement and 10 wt% pore-forming template. Calcium-based particles containing 5 wt% cement and 10 wt% cellulose demonstrated the highest thermal storage capacity. The steam-containing atmosphere reduced the heat storage ability of the calcium-based particles, but it greatly improved their mechanical characteristics. After undergoing 50 cycles with 10 vol% steam injection during calcination, the calcium-based pellets exhibited a mere 6.09 % reduction in E¯g,N compared to the heat storage cycle without steam addition. In contrast, the average crushing strength experienced a remarkable increase of 42.65 %, while the attrition rate decreased by 30.18 %.