Characteristics and Reactivities of Solid Wastes Sorbent for Medium-temperature Flue Gas Desulfurization

Abstract

In this study, sorbent for flue gas desulfurization is prepared using metallurgical dusts (MD) abundant in iron oxides as the main active component, lime as promoter, and amylum as special additive. The reactivity of the sorbent is conducted in a quartz fixed-bed reactor within the medium temperature range of 300°C–750°C under heating and isothermal conditions, while the physical and chemical properties of the sorbent are measured using ICP-AAS, SEM, XRD, and so on. The experimental results indicate that with temperature increasing from 300°C to 750°C, breakthrough sulfur capacity of the sorbent increases from 0.0257 gS/gSorbent at 300°C to 0.1391 gS/gSorbent at 650°C, then decreases to 0.0836 gS/gSorbent at 750°C, and that the removal efficiency of SO₂ and breakthrough sulfur capacity of the sorbent depend on the chemical kinetics of Fe₂O₃ and CaO in the temperature range of lower than 600°C, but on the thermodynamic equilibrium of sulfuration of Fe₂O₃, the thermal stability of the Fe₂(SO₄)₃ and content of CaO in the range of higher than 650°C. Physical and chemical analyses of the fresh and reacted sorents further verify that the effective and dominating component of the sorbent is Fe₂O₃ within the temperature range of lower than 650°C, while is CaO in higher than 650°C.

Keywords:

• flue gas desulfurization
• solid wastes
• sorbent