Assessment of limestone treatment with organic acids for CO2 capture in Ca-looping cycles

Enhanced CO2 capture by biomass-templated Ca(OH)2-based pellets

“…The current composite pellets exhibited 2-2.5 times higher capture capacities than the 0.1 g/g capacity achieved by amine-based sorbent at 25°C [32]. Also, these uptakes appear comparable to those achieved by sorbents treated with organic acids, suggesting that the current sorbents are much more promising given the low price of biomass materials compared to organic acids [23] or synthetic organic materials [33].…”

“…On the other hand, doping limestone with mineral acids, such as HBr, was found to result in a pronounced improvement in the CO 2 uptake of the doped sorbent [21]. However, these modification techniques risk being cost-ineffective due to the relatively high cost of chemicals and treatment procedures and require further development [22,23]. Pelletization still allows the possibility of sorbent doping but has also been proposed to improve the mechanical strength of the sorbent using different binders, such as bentonites [24], kaolin [25], alumina [25], and calcium aluminate cement [19,26].…”

High temperature CO2 sorbents and their application for hydrogen production by sorption enhanced steam reforming process

“…The reaction of limestone with organic acids is known as another chemical treatment that improves the sintering resistance of CaO sorbents derived from limestone by altering the porous structure [120][121][122][123][124]. Li et al [121] investigated the modification of limestone with 50% acetic acid solution (the molar ratio of acetic acid to calcium: 1.5:1).…”

“…The carbon combustion during the secondary calcination step (in air) promoted the dispersion of particle agglomerates and enhanced the material porosity. Ridha et al [124] proposed the treatment of limestone by four organic acids with the aim of improving the cyclic CO 2 capture performance of limestone. The increase of CO 2 capture capacity for the modified sorbents was explained by the fact that the acidification by organic acids widened the pores of the modified sorbents and improved the resistivity of them to sintering phenomenon.…”

CO2 capture by calcium aluminate pellets in a small fluidized bed

“…However, limestone can also be reacted directly with acids stronger than carbonic acid to form the precursors directly [5]. The most simple precursor is Ca(OH)2 [6]; however, numerous other precursors have been investigated, such as calcium acetate, calcium formate, calcium nitrate [7], amongst others.…”