Desulfurization performance and mechanism for H2S from blast furnace gas over FAU zeolite sorbent

Abstract

The desulfurization of blast furnace gas is crucial to meet the strict requirements for clean production of steel industry. However, the composition of blast furnace gas is complicated, and the gases of H2O, CO, CO2, and O2 would significantly affect the desulfurization activity. Therefore, the desulfurization performance for H2S in simulated blast furnace gas by Na-type FAU zeolites with different Si/Al was investigated. The physicochemical properties of zeolite sorbents were measured, and their correlation with desulfurization performance was studied. Moreover, the adsorption mechanism of H2S was investigated. The breakthrough sulfur capacity improved with the increase of relative crystallinity, Na+ content, specific surface area, and the decrease of Si/Al ratio. The adsorption mechanism of H2S on Na-type FAU zeolite was proposed. One is the hydrogen bond interaction between the bridging hydroxyl groups and H2S, and the other one is the base-acid interaction between sodium ion and H2S. In blast furnace gas, when interacting with Na+, H2S would be transformed into S, which further oxidized into thiosulfate and sulfate by O2.