Preparation, Property And Kinetic Characterization Of Mesoporous Rare Earth Oxides Sorbent For Hot Coal Gas Desulfurization

Using a sol-gel method, supported and unsupported La_xFe_yO_zsorbents wereprepared. The effects of composition of sorbent, reaction temperature, WHSV, hot coalgas composition, reactor types and support on the breakthrough sulfur capacities wereinvestigated. When the content of H₂S is0.86%（vol.） in the feed gas, thebreakthrough sulfur capacity of50%La_xFe_yO_z/MCM-41（La:Fe=1:2） achieved7.94g S/100g sorbent, and approximately63.9%of theoretical sulfur capacity was utilized.The results of ten successive desulfurization-regeneration cycles revealed that50%La_xFe_yO_z/MCM-41（La:Fe=1:2） sorbent presented high performance andstability for hot coal gas desulfurization. The sorbents were characterized by means ofBET, HRTEM, XRD, XPS techniques.Samarium-based sorbents SmMeOxsupported on MCM-41and SBA-15（Me=Fe, Zn, Co） can directly produce elemental sulfur during both sulfidation andregeneration, which was confirmed by TOF-MS technology. The results of successivedesulfurization-regeneration cycles of samarium oxide sorbent illustrated that theformation of elemental sulfur was the role of samarium element.An equivalent pore model is proposed to describe the kinetic behavior of gasesover perovskite-type oxide/SBA-15sorbents for H₂S removal in hot coal gas. Therelationship of the rate constant of apparent chemical reaction and diffusioncoefficient with temperature were expressed by the Arrhenius formula. ForLaFeO₃/SBA-15, the obtained apparent activation energy （Ea） of chemical reactionand diffusion activation energy （E_d） are26.99and44.00kJ·mol^-1, respectively, basedon the experimental data of desulfurization process.