Sol-gel-derived alumina-supported copper oxide sorbent for flue gas desulfurization

Nanostructed mesoporous CuO/gamma-Al2O3 granular sorbents were prepared by the sol-gel method. Performance of the sol-gel-derived CuO/gamma-Al2O3 sorbents for SO2 removal was studied in a fixed-bed adsorption system. SO2 breakthrough curves with a feed stream of air containing 2000 ppm SO2 were measured at different temperatures (300-500 degrees C) and flow rates (interstitial velocity of 0.25-6.96 cm/s). The optimum sulfation and regeneration temperature on the sol-gel-derived sorbent was found to be 400 degrees C. The properties of the sol-gel-derived sorbents are compared with a similar sorbent from a commercial source used in the pilot-scale copper oxide flue gas desulfurization process. At high temperatures (>400 degrees C) the sol-gel-derived CuO sorbents exhibit catalytic properties for converting SO2 to SO3. The crush strength of the sol-gel-derived sorbents is about 5 times that of the commercial sample, while the attrition rate of the former is about 4-10 times smaller than the latter. The SO2 sorption capacity of the sol-gel-derived sorbent is about 3 times that of the commercial sorbent with a similar amount of CuO loading. The better mechanical properties and higher sulfation capacity of the sol-gel-derived alumina-supported copper oxide sorbents are due to their unique microstructure and the method used for coating CuO. The sulfation and regeneration study shows good regenerability and stability of the sol-gel-derived CuO/gamma-Al2O3 sorbents.