Flue Gas Desulphurization By Electrochemical Unite Catalytic Oxidation Method

Flue gas desulphurization by electrochemical method is a new,clean and efficient desulfurization method which has good foreground.The main mechanism of it includes using iodine as the absorbent to remove sulfur dioxide and regenerating the iodine by electrochemical method.The electrochemical oxidation behavior of iodide ion on different electrode had been investigated in this paper.The technical conditions and the optimum parameters of bunsen reaction in the packing tower had been studied.The electrochemical oxidation behavior of iodide ion in a variety of media had been investigated by the measurement of cyclic voltammetry,chronoamperometry and linear sweep voltammetry.Changes of graphite electrode surface in the whole electrochemical reaction process had been investigated by in situ fourier transform infrared spectroscopy technique,the scanning electron microscope and X-ray photoelectron spectroscopy.The electro-oxidation behavior of iodide ion on the graphite electrode had been studied.The results show that the dissolution and precipitation of iodine membrane occur during the electro-oxidation process of iodide ion in the acidic medium at the low voltage.Meanwhile,the graphite electrode itself may take an electro-oxidation.When the polarization potential increases,high-valent iodine-containing compounds could be formed by anodic oxidation of iodide ion,not by iodine which was the product of anodic oxidation.And the intercalation and electrode oxidation reaction also occurred on the graphite surface which indirectly influenced the electrode properties.The electro-oxidation behavior of iodide ion in the neutral solution witch had been investigated on graphite electrode was similar to the result showed on the Pt electrode.Side electro-oxidation of graphite itself and the insertion of Na+,K+ and SO42-occurred on the graphite electrode.In alkaline medium,the generated iodine was easy to react with hydroxyl to form iodate,and also iodine membrane was formed under the condition of low concentration of NaOH solution.Graphite surface would easily combine with-OH,-COOH and C=O functional groups.In alkaline medium,the intercalation reaction of iodine,sodium and potassium ions make the graphite composition changed,accelerating the loss of electrode.The oxidation behavior of I2/I-on dimensional stable anode and the electrochemical reaction under the influence of acidity and iodine ion concentration had been studied.The results show that the increased of acid concentration leads to the I3-adsorption characteristics enhanced,and then the potential of current peak take a negative shift.Electrochemical oxidation of iodide ion on dimensional stable anode was controlled by the diffusion process of iodide ion to the electrode.The mechanism of sulfur dioxide absorption process in bunsen reaction had been researched.According to the solution infiltration theory,the transfer absorbing model of sulfur dioxide was established.Packed tower was used as Bunsen reactor with pall ring as its packing.It is found that the desulphurization efficiency gets enhanced with the increasing of the packing height.With the parameters of gas flow within 5.35L·min-1,suitable liquid-gas rate grater than 4L·m-3 and S02 volume concentration at 2700ppm,it has a high desulfurization efficiency.The acidity of the reactive agent has no influence on desulphurization efficiency.The desulphurization efficiency would reach to a optimum value with the molar ratio of I2/SO2 at 1.5 under the temperature of 60?.