Catalytic reduction of SO2 under the regeneration of off-gas containing oxygen over Cu-Sn-Zr-based oxides for the hot coal gas desulfurization process

•Catalytic reduction of SO2 over Cu-SnO2-ZrO2 catalysts.•Catalysis of Cu-Sn-Zr based catalysts for sulfur recovery under oxygen containing condition.•Role of Cu-promoter for COS intermediate mechanism in catalytic reduction of SO2.

This study examined the activity of Cu-Sn-Zr-based catalysts for the direct sulfur recovery process under the regeneration gas containing oxygen, which consisted of sulfur dioxide and nitrogen as the main components. The catalytic reaction behavior was investigated with the addition of a copper promoter, and the reactive temperature for SO2 reduction was investigated according to the change in temperature by increasing and decreasing the temperature in the processes in stages. The catalytic reaction pathway changed with the catalysis of the promoter, and the activity of the reacted catalyst was higher than that of the fresh catalyst due to the sulfidation of the Cu-promoter. CuS leads to a COS intermediate mechanism, and prevents the deactivation of Cu-Sn-Zr-based by oxygen contained in the regeneration gas.

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