Pellets of a novel, high temperature CO2 sorbent, made of CaO-impregnated porous Y2O3, were prepared. Yttria pellets were synthesized from a mixture of yttria powder and a softener. A combination of ethylene glycol, used as a softener, and a casting method yielded mechanically stable pellets after calcination at 800ºC. Treatment of the Y2O3 support at higher temperatures further increases the pellets strength. The same effect of pellets strengthening was observed after yttria impregnation with CaO. Sorption capacity of the pellets with CaO content of 9 wt. %, measured at isothermal conditions of 740ºC, reaches 7.5 wt. % for shorter recarbonation time of 20 min and 8.5 wt. % for a longer time of 1 hour. In this respect, sorption properties of pelletized CaO/Y2O3 are similar to those of powdered material. A distinctive feature of the pelletized CaO/Y2O3 sorbent pretreated at high temperatures is the increase in capacity during the initial cycles.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.