Flue Gas Desufurization And Its Kinetics Using Seawater

The seawater desulphurization is a technic to absorb SO₂ in flue gas using seawater. Technically, it is mature, simple and convenient to run, and therefore incomparable with other desulphurization technics. It is efficient to control SO₂ emission in power plants, and to reduce dust emission at the same time, which plays an important role in improving the air quality. The addition of Ca(OH)2 and/or white slurry can increase the alkalinity of seawater, and hence improve the absorptivity of SO₂ in flue gas.Desulphurization using artificial and natural seawater was investigated in this thesis. The effects of temperature, flow rate of the flue gas, the concentration of SO₂ and some cations on SO₂ absorptivity were studied first. On this basis, the effects of addition of Ca(OH)2 and white slurry on SO₂ absorptivity were further studied. And finally, the absorbing kinetics of SO₂ using artificial seawater, natural seawater and seawater with enhanced alkalinity were examined. The major results and conclusions are summarized as below:1. The SO₂ absorptivity decreases with the increase of temperature, flow rate of flue gas and the concentration of SO₂.2. Cations such as Ca²⁺, Mg²⁺, Fe²⁺ and Mn²⁺ have little effect on SO₂ absorptivity.3. The alkalinity has significant effect on SO₂ absorptivity. The pH values of both artificial and natural seawater increased with the addition of Ca(OH)2 and/or white slurry, leading to enhanced SO₂ absorption, which increases with increasing the concentration of Ca(OH)2 and/or white slurry.4. The absorption of SO₂ using either artificial, natural seawater or seawater with enhanced alkalinity obeys a first-order kinetics. 5. There is no effect of temperature on the initial reaction rate of the absorption of SO2 using artificial, natural seawater and seawater with enhanced alkalinity.