A Study on Desulphurization of Flue Gases by the Active Carbon Process Using Steam Desorption (Part 3)

Variation of properties of active carbon used in continuous run of a test plant employing the active carbon process using steam desorption was measured, and the relationship between these properties and sulphur dioxide adsorption capacity was studied.During the continuous run, the porous structure of active carbon developed, and the BET surface area expanded slightly. The total oxygen content of active carbon also increased. Thus it reached at 17.6wt% being over two times of that in the original active carbon after 1, 200 hours. The oxygen existed mainly as surface oxides in active carbon. The surface oxides were classified into basic surface group and acidic surface group for quantitative analysis. The results indicated decrease in the amount of basic surface group and increase in the acidic surface group.The sulphur dioxide adsorption capacity of active carbon did not show a relationship with its structural properties. It was found that the adsorption capacity is influenced by the chemical properties of surface oxides.It was estimated that the basic surface group functions as the activation point of chemisorption with oxidation for sulphur dioxide adsorption.