Incorporation of CaO into novel Nd2O3 inert solid support for high temperature CO2 capture

A novel inert solid support of Nd2O3 was introduced to enhance the cyclic carbonation/calcination performance of CaO-based sorbents. CaO particles were incorporated into Nd2O3 by a wet-mixing method, using three organometallic precursors (OMPs) as calcium precursors and neodymium(III) acetate hydrate as inert support precursor. For comparison, CaO-based sorbents directly produced from precursors and the naturally occurring sorbent (limestone) were also investigated. FSEM and EDAX results revealed that the ultrafine active specie of CaO particles were homogeneously dispersed into Nd2O3 inert support. As a result, an improved durability and higher carbonation conversion were observed owing to the retarded sintering and the delayed diffusion controlled stage respectively for the sorbents investigated. The performance of the synthetic sorbents also relies on the precursor. When calcium dl-lactate pentahydrate (CaL) was used to incorporate CaO into the inert support Nd2O3, the highest conversion and best durability were obtained. The effect of calcination temperatures on the sorbent durability was also investigated. Under a relatively severe calcination temperature of 900 °C, a high conversion of about 67% were obtained after 100 carbonation/calcination cycles for a sorbent synthesized from calcium dl-lactate pentahydrate (CaL) and neodymium(III) acetate hydrate. When the calcination temperature was changed to a mild one of 800 °C, a significantly high conversion (>92.5%) was maintained over 100 carbonation/calcination cycles. Besides, no apparent capacity decline was observed for the sorbents after granulation.