Study On Absorption Of SO₂ By H₂O₂ And Fenton Intensified By High Gravity Technology

Environmental protection have become a serious challenge with the rapid development of China's economy.Air pollution is one of the major environmental problems which we meet nowadays.SO2 is a kind of gas that has a large amount of emission and can cause serious environmental hazard.Most plants in China use limestone-gypsum method for flue gas desulfurization.However,this method has some disadvantages such as huge equipment investment,large amount of solid waste and so on.Liquid-phase oxidation technology as a new method for desulfurization process can absorb SO2 rapidly and realize the utilization of sulfur.In this study,the high-gravity technology was used to intensify the absorption process of SO2 by liquid-phase oxidation method.Simulated flue gas containing SO2 was absorbed by H2O2 and H2O2/Fe(?)(Fenton)solution in a Rotor-Stator Reactor(RSR).The effects of operating conditions on the absorption percentage of SO2 were investigated.The gas-phase overall volumetric mass transfer coefficient Kya in the process of SO2 absorption into H2O2 was obtained under reasonable assumptions.In addition,the effects of operating conditions on Kya were also studied.The main results are as follows.(1)The effects of various operating conditions on SO2 absorption was investigated with the system of SO2 absorption into H2O2 in RSR.The results showed that the suitable operation conditions were gas flow rate of 1.5 m3/h,SO2 inlet concentration of 4000 mg/m3,liquid flow rate of 3.75 L/h,gas-liquid ratio of 400,H2O2 concentration of 17.84 mmol/L,rotation speed of RSR of 800 r/min,pH value of absorbent of 6.9 and temperature of 25 ?.Under the conditions,the absorption percentage of SO2 reached 85%.In addition,when 0.25%(v/v)of promoter A was added into the H2O2 solution,SO2 absorption percentage increased by 12%;when 0.2‰ of promoter B was added into the H2O2 solution,SO2 absorption percentage increased by 14%.(2)The effects of various operating conditions on SO2 absorption was investigated with the system of SO2 absorption into Fenton solution in RSR.The results showed that the suitable operation conditions were gas flow rate of 1.5 m3/h,SO2 inlet concentration of 4000 mg/m3,liquid flow rate of 3.75 L/h,gas-liquid ratio of 400,H2O2 concentration of 17.84 mmol/L,Fe2+ concentration of 3.56 mmol/L,rotation speed of RSR of 800 r/min,pH value of absorbent of 2.5 and temperature of 28 ?.Under the conditions the absorption percentage of SO2 reached 89%.(3)The effects of various operating conditions on the gas-phase overall volumetric mass transfer coefficient Kya was investigated with the system of SO2 absorption into H2O2 in RSR.The result showed that Kya increased with the increase of rotation speed of RSR and liquid flow rate.Kya increased first and then decreased with the increasing gas and liquid flow rates.Addition of promoter A and promoter B have a significant impact on the value of Kya.Compared with the systems without promoter A or promoter B,Kya increased by 40%or 50%,respectively when 0.25%of promoter A or 0.2‰ of promoter B was added into H2O2 solution.