Numerical Simulation And Optimization Of Sintering Flue Gas Desulfurization Process In F100-SDA Semi Dry Desulfurization Tower

The sulfur dioxide produced by sintering flue gas accounts for more than 70%of the total emission of iron and steel enterprises,and about 90%in some enterprises.Therefore,reducing sulfur dioxide emission is an important problem to be solved.At present,desulfurization methods are divided into three types:dry method,wet method and semi dry method.Rotary spray drying desulphurization technology is a desulfurization method in semi dry process.Because of its low operating cost,small footprint and high desulfurization rate,it has become a widely used semi dry technology.In this paper,the SDA desulfurization tower is analyzed by numerical simulation,and the velocity field,temperature field,concentration field and chemical reaction of substances in the tower are explored according to the structure parameters and operation parameters.The structural aspects are as follows:1)the influence of the length of the upper layer on the Swirl Characteristics under the condition of the existence of the spiral case is studied.According to the matching relationship between the length and the spacing of the spiral blades,the design rules of the number of the swirl sheets are proposed;2)the influence of the flue gas outlet position,the length and number of the swirl sheets on the desulfurization efficiency is studied;3)the improvement of the spiral case structure.The results show that:when the volute does not exist,with the increase of the length of the hydrocyclone,the effect on the swirl is obvious,showing a trend of increasing at first and then tending to be stable;when the volute exists,the change of the length of the hydrocyclone has little effect on the swirl.It is found that the ratio of length to spacing is 2.4?3.6,and the reference range of the number of swirl vanes is 24?68.Through the influence of the flue gas outlet position,the length and number of cyclone blades on the desulfurization efficiency,it was found that the number and length of the flue gas outlet had no obvious effect on the desulfurization efficiency.The flue gas outlet position moved up,which reduced the residence time of flue gas in the tower,and the desulfurization efficiency decreased to 74.1%.The downward movement of the flue gas outlet position made the gas flow unevenly distributed in the tower,and the desulfurization efficiency decreased to 79.6%.Compared with the original volute,the improved volute can obtain more uniform smoke distribution.The research on operation is as follows:the influence of flue gas velocity,SO₂concentration in flue gas,flue gas temperature and reduction rate of humidified water in slurry on flow field and desulfurization efficiency is studied.The results show that with the increase of flue gas velocity,the desulfurization efficiency decreases from11m/s to 17m/s,and the desulfurization efficiency decreases from 84.1%to 78.8%.When the temperature increases from 390 K to 420 K,the desulfurization efficiency increases from 84.4%to 87.2%,and then decreases to 86.9%.With the increase of SO₂concentration in flue gas,the desulfurization efficiency decreased slightly.When SO₂concentration increased from 636 mg/m³to 1036 mg/m³,the desulfurization efficiency decreased from 86.7%to 85.8%.With the increase of the reduction rate of humidified water in slurry,the desulfurization rate decreased and the temperature increased.The reduction rate of humidified water is from 0%to 100%,the desulfurization efficiency is reduced from 87.2%to 72.9%,and the temperature is increased from 107?to 127?.