Research On Scaling Of Limestone Wet Flue Gas Desulfurization Spray Tower

In this paper,the energy consumption structure and the emission of SO₂ in China are described firstly,and the advantages and disadvantages of various flue gas desulphurization technologies are introduced,among which the wet limestone flue gas desulphurization technology has become the mainstream desulphurization technology with the characteristics of perfect technology,high SO₂ removal rate and strong adaptability of coal.But there are some problems such as scaling,corrosion and waste-water treatment.In the face of scaling problems,this paper analyzes the scaling types,scaling mechanism and influencing factors of wet flue gas desulfurization system,studies the buffering effect on pH value of different scale inhibitors,and prepares experimental slurry according to the proportion of desulfurization productss in order to study the scale inhibition performance of different scale inhibitors.PH value is an important factor of affecting the wet desulphurization system scaling,and the results of pH buffer experiment show that the EDTA,PESA,adipic acid all have certain buffering effect on saturated CaCO₃ solution at pH 5.8⁶.2,among them when the concentration of EDTA is 1.5g/L,the concentrations of PESA are 0.005g/L and0.01g/L,the concentration of adipic acid is 0.15g/L,the buffer effect gets the best point.EDTA,PCA,PESA and adipic acid all have certain buffering effect on saturated Ca（OH）₂ solution at pH 6.5⁷.5.When the concentration of EDTA is 1.5g/L,the concentration of PCA is 0.005g/L,the concentrations of PESA are 0.005g/L and 0.01g/L,the buffer effect gets the best point.The buffering effect of adipic acid with different concentrations is basically the same.According to the proportion of desulphurization products,the experimental slurry was configured,and the scale inhibition performance of different scale inhibitors,as well as the influence of temperature,agitation speed and time on the scale formation were studied by the method of rotating slurry.The experimental results showed that the concentration of scale inhibitor and agitation speed had a greater impact on the scale formation amount,while the temperature and time had a smaller impact on the scale formation amount.The scale formation can be reduced by adding EDTA,PCA,PESA,adipic acid and MgSO₄ into the slurry.Among these five kinds of scale inhibitors,PCA and PESA have good scale inhibition effect.When PCA with the concentration of15mg/L,stirring speed of 250r/min,temperature of 60℃and time of 3 hours,it has the minimum scale quantity hanging on the chip with the quantity of 65.22×10^-5g/cm².When PESA with the concentration of 10mg/L,stirring speed of 250r/min,temperature of 60℃and time of 3 hours,it has the minimum scale quantity hanging on the chip with the quantity of 91.32×10^-5g/cm².Let these two parts be compounded with the proportion of1:1 quality distribution,it is found that the compound scale inhibitor has a certain synergy superimposition,when the compound scale inhibitor with the concentration of15mg/L,stirring speed of 250r/min,temperature of 60℃and time of 3 hours,it has the minimum scale quantity hanging on the chip with the quantity of 49.55×10^-5g/cm².