Principle of SO2 Removal by Activated Carbon
The process of SO₂ removal by activated carbon mainly consists of physical adsorption and surface chemical reactions.
When no water vapor is present in the flue gas, the SO₂ in the flue gas mainly undergoes physical adsorption, with a low and unstable adsorption capacity. When the flue gas contains sufficient water vapor and oxygen, activated carbon flue gas desulfurization is a process in which physical adsorption and surface chemical reactions occur simultaneously.
Physical adsorption takes place first, and then, in the presence of water and oxygen, the SO₂ adsorbed on the surface of activated carbon is catalyzed and oxidized into H₂SO₄, which is stably stored in the pores on the surface of activated carbon. Physical adsorption and surface chemical reactions jointly determine the total SO₂ adsorption capacity of activated carbon. Physical adsorption is closely related to the physical properties such as the pore structure on the surface of activated carbon, while surface chemical reactions are related to the chemical properties of the basic functional groups on the surface of activated carbon. The relevant chemical reaction equation is:
2SO2 + O2 + 2H2O —-> 2H2SO4
