SULFIDATION - REGENERATION CYCLES OF ZNO-CONTAINING AND CAO-CONTAINING SORBENTS

The desulfurization performance of regenerable metal oxides was tested in a fluidized bed reactor. A reductive regeneration step was applied between the oxidative regeneration and the subsequent sulfidation when the metal oxide was ZnO. The reaction of the sulfided CaO sorbents with H2O and CO2 produced CaCO3 that decomposed under an inert atmosphere. The H2S removal ability of the regenerated CaO sorbents increased when H-2 and CO were added to the regenerative gas mixture. Sorbents derived from the impregnation of a metal oxide on magnesia exhibited larger desulfurization capacity than those derived from the impregnation of the same oxide on alumina. The treatment of the CaO sorbents with methanol increased the surface area, the pore volume, and the desulfurization capacity of the sorbents. The pore structure analysis of sorbents at different stages of the sulfidation -regeneration cycle showed insignificant changes in the physical properties of the sorbents.