A DESULFURIZATION MATHEMATICAL MODEL AND A PILOT EXPERIMENT BY SPRAYING NaOH SOLUTION INTO DOWNSTREAM FLUE DUCT OF A COAL-FIRED INDUSTRIAL BOILER

In a wet desulfurization process NaOH solution is sprayed into flue duct, small droplets are then formed and react directly with gaseous SO₂ in FG. In this paper a two-phase mathematical model based on dual film mass transfer theory and boundary layer theory on the surface of droplet is proposed to describe the reacting processes between the gaseous SO₂ and a single droplet Then according to the droplet diameter distribution function, a set of formulas to estimate the binding capability of droplets on SO₂ and to predict the desulfurization efficiency are established. Through numerical calculation, key factors such as pH value of droplets, the ratio of spraying NaOH solution volume to the volume of FG, etc. are analyzed and discussed. Additionally, a SO₂ removal pilot experiment is carried out on the flue duct of a coal-fired industrial boiler with steam capacity of 10T/h to test the SO₂ removal rate.