Characteristics and desulfurization-regeneration properties of sol–gel-derived copper oxide on alumina sorbents

Abstract

Mesoporous alumina supported copper oxide granular sorbents were synthesized by the sol–gel method using different raw materials. The copper loading in the sorbents was varied from 5 to 20-wt.% CuO. The effect of the copper content on the surface area of the sorbents and dispersion of the active species was studied. Samples with <14 wt.% CuO did not show any crystalline copper containing phase. For CuO/γ-Al 2O 3 with 8 wt.% CuO, most of the copper species consisted of Cu 2+ ions and no sulfide species were found. The optimum temperature for operation of the sol–gel derived sorbents was 400 °C at which more than 85% of the initial sulfation capacity is maintained up to three sulfation-regeneration cycles. The pore structure, crush strength, sulfation capacity and regeneration properties of the sol–gel derived sorbents were studied and compared with those of the similar commercial sorbents used in pilot scale fluidized-bed copper oxide process for flue gas treatment. The sol–gel-derived mesoporous copper oxide coated alumina granules, with a surface area of 220–248 m 2/g, pore volume of 0.46–0.48 cm 3/g, and pore diameter of 6.7–8.8 nm, offer higher surface area, more uniform pore size distribution, and higher crush strength than the commercially available sorbents for the copper oxide process. For similar copper oxide content the sol–gel derived sorbents showed superior sulfation and regeneration properties than the commercial sorbents, in terms of sulfation capacity, regenerability, and SO 2 concentration in the regenerated effluent.