Study On Demercuration By Mini-Hydrocyclone And Fenton

Because of the durability, easy mobility, high concentration and high biological toxicity, mercury and its compounds, have aroused high attention of the environmental protection departments. In this paper, physical and chemical characters, sources of mercury and the control methods of gaseos mercury in coal combustion flue gases are discussed. According to the research, the oxidation absorption has the highest mercury removal efficiency. The common oxidation of coal-fired flue gas mercury are potassium permanganate, sodium hypochlorite, etc. However, these antioxidants may need further treatment, due to secondary pollution. Fenton reagent is a green and efficient mercury oxidant, which is composed of hydrogen peroxide and ferrous ion Currently, Fenton oxidation mercury technology is still in the stage of laboratory.The conditions of Fenton reagent oxidation mercury are studied in this paper. Effects of initial hydrogen peroxide concentration, ferrous ion concentration, pH, and reaction temperature on mercury oxidative absorption in Fenton reagent were investigated. Based on mass transfer parameters of reactor measured by chemical method, mass transfer and reactor kinetics were also studied. The primary conclusions were as follows:(1) The efficiency had an optimum value with the change of hydrogen peroxide concentration In the presence of ferrous ion, the efficiency improved quickly. When the concentration of H2O2 is 0.1mol/L, and the ferrous ion concentration is 0.05mol/L, and the pH is in the range of 2-4, the efficiency of mercury was the highest, and higher temperature inhabited the mercury removal(2) Mass transfer reaction kinetics was also discussed with surface renewable theory. Reaction rate constants are 3.30×104 m3/(mol s) and 6.51×104 m3/(mol·s), corresponding to the reaction temperatures on 303 K and 313 K when pH=2, respectivly. Activation energy, which indicates rate constant is sensitive to temperature if activation energy is very large, is 53.45kJ/mol, and the frequency factor is 5.410×1013m3/(mol·s).The mass transfer kinetics in hydrocyclones reactor was also discussed in this paper. The experiment measured the coefficient of mass transfer conditions and specific surface area of the hydrocyclone. The results show that the hydrocyclones reactor can provide a better contact area for gas liquid reaction.