Experimental Study of SO2 Removal by Powder Activated Carbon in Fluidized Bed Reactor

The aim of this paper is to study SO₂ adsorption by the activated carbon (AC) in the circulating fluidized bed reactor. Five different kinds of activated carbons were chosen to determine whether activated carbon could be used effectively to remove SO₂ from coal combustion flue gas. The fluidized bed reactor was used to study the capability of AC in SO₂ removal with concentrations of SO₂ (1000 ppm), O₂ (20%) and H₂O (3-8%) and react temperature (40-72°C). The pore structure, pore size distribution and functional groups of five activated carbons were analyzed and characterized in this paper. The results showed that SO₂ adsorption capability of CAC and MAC was larger than others. In general, there was no correlation between SO₂ adsorption capacity and surface area. Basic functional group was benefit for SO₂ adsorption. React temperature, C/S mole ratio, oxygen and water concentration has greater effect upon the SO₂ removal. The optimum conditions for desulphurization by CFB reactor were H₂O (8%) outlet temperature (60-65°C), and C/S mole ratio (80). In fluidized state, the absorption capacity of activated carbons varied from 45-81 mg/g, and the average adsorption rate was 25.5 to 40 mg/(g · s).