The Kinetic Studies Of Regeneration Reaction Of Wet Desulfurization By Complex Iron

The complex iron wet oxidation method is a method for removing sulfides based on Fe(III)/Fe(II)redox couple under weak alkaline or alkaline conditions.The desulfurization absorption efficiency is high and the operability is strong.Most of the desulfurizers can be regenerated and economical,it is also environmentally friendly,which is one of the hot spots of desulfurization research.Compared with the rapid absorption reaction of sulfide,the regeneration process of Fe(III)is relatively slow,which severely limits the desulfurization efficiency of the entire desulfurization system.The purpose of the thesis is to establish a kinetic model that can describe the aerobic oxidation of complex ferrous iron during regeneration.The model can accurately describe the relationship between the apparent reaction rate of Fe(II)oxidation and the solution temperature,solution p H,oxygen content and reactant concentration.In this thesis,the oxidative regeneration system of EDTA-Fe(II)solution was studied.The reaction kinetics during the regeneration step of desulfurization iron ion was studied by electrode potential method,and used as the basis for establishing the model.By studying the change of oxygen content in a single bubble,the theoretical model of the complex ferrous iron concentration in the regeneration liquid with time is estimated under different gas-liquid ratio,regeneration temperature and p H value.The experimental results show that the apparent reaction rate of regeneration increases with the increase of EDTA-Fe(II)concentration,and the ferrous reaction order is 0.902.The apparent reaction rate of regeneration increases with the increase of oxygen content in the gas phase,and the corresponding reaction order is 0.8.The apparent reaction rate of regeneration decreases with the increase of hydrogen ion content in the solution,indicating that the higher the hydrogen ion content is not conducive to the regeneration reaction,the reaction order of the regeneration reaction to the hydrogen ion concentration is-0.152,but too high p H will cause the complex iron is unstable,and the system will precipitate iron hydroxide.Therefore,the p H of the industrial wet desulfurization system solution is usually less than 10.In the temperature range of 30?60°C,the apparent reaction rate of regeneration increases with the increase of temperature,and the activation energy of regeneration reaction is 14.24 k J/mol.Based of experimental results,a kinetic mode of regeneration process was built to help design of regeneration reactor,and the model calculation results are in good agreement with the measured data,which proves the reliability of the model.the model has certain theoretical guiding significance for guiding the design of the complexed iron desulfurization regeneration reactor and the amount of air blasting,the addition amount of the complexing agent,and the addition position in desulfurization process.Finally,a claus exhaust gas treatment device with a capacity of 1500 Nm~3/h is designed,and the key parameters such as tower diameter,tower height and air volume are simply calculated.The calculation results show that the reactor tower is 10.95m high,the column diameter of the absorption unit is 3.65m,and the absorption liquid must be at least 3m high to control the content of hydrogen sulfide below 10 ppm at the outlet of tower R101.In order to ensure the stable and continuous operation of the desulfurization-regeneration reactor,the air blast volume should not be less than 660m~3/h.