Desulfurization of H2S using cobalt-containing sorbents at low temperatures

The sulfidation of cobalt oxide with H2S was proposed for the desulfurization process at low temperatures. The reaction is studied with a packed-bed reactor and TGA (thermogravimetric analysis) equipped with in situ reactor experiments in the range 300-500∘C. Due to larger particle size, the bulk cobalt oxide showed slower sulfidation rate having insufficient removal efficiency. Supported cobalt oxide exhibited high removal efficiency and degree of sulfidation at 300-400∘C primarily because of its smaller grain size. Among the three sorbents tested, extremely low values of activation energy and frequency factor were observed in Co3O4/TiO2; the rate was almost independent of temperature. The experimental data were successfully predicted by shrinking core model having a bimodal distribution in grain size. From the calculated effective diffusivity, De, and kinetic constant, k, the diffusion resistance controlled the overall reaction rate of bulk oxide sorbent.