Publication Date:
2012-02-02
Description:
Cyclic CO 2 capture using CaO-based sorbents derived from commercial pure micro-sized CaCO 3 and nano-sized CaCO 3 was investigated, focusing on the different characteristics of carbonation conversions, carbonation rates, surface areas, pore volumes, morphological changes, and microstrains of two sorbents during high-temperature reactions. The results indicated that the CaO-based sorbent derived from nano-sized CaCO 3 (NC-CaO) provided higher carbonation conversions and carbonation rates than the CaO-based sorbent derived from micro-sized CaCO 3 (MC-CaO) in the cyclic CO 2 capture reactions. Furthermore, NC-CaO retained its fast carbonation rate at the beginning of each cycle for several tens of seconds. In contrast, the carbonation rate of MC-CaO diminished with an increase in the cycle number. Unfortunately, NC-CaO sintered more easily. Its grains, which were composed of numerous spherical nanocrystallites, suffered from dramatic morphological changes during high-temperature reactions. A mechanism of grain boundary migration was employed to explain the sintering of CaO-based sorbent. The smaller crystallites were more susceptible to be merged by the bigger crystallites during high-temperature reactions. CaO-based sorbents derived from commercial pure micro-sized CaCO 3 and nano-sized CaCO 3 were applied for cyclic CO 2 capture. Carbonation conversions and rates, surface areas, pore volumes, morphological changes, and microstrains of the two sorbents during high-temperature reactions were investigated. The nano-sized sorbent provided higher carbonation conversions and rates during looping cycles.
Print ISSN:
0930-7516
Electronic ISSN:
1521-4125
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
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