Study On The Properties Of Complex Absorption Of Nitric Oxide By Fe²⁺-EDTA

Since the first industrial revolution in the eighteenth century,the amount of flue gas generated by coal combustion has increased,the nitrogen oxides in coal-fired flue gas have caused great harm to humans and the ecological environment,therefore,"13th Five-Year Plan"has set more stringent control standards for nitrogen oxide emissions.Nitric oxide?NO?in flue gas accounts for 90%of nitrogen oxides,therefore,the control of nitric oxide in coal-fired flue gas is the focus,the nitric oxide molecule contains a diatomic?bond,and the redox reaction has higher activation energy and lower reactivity,which makes it difficult to remove NO.Many industrial company have adopted technologies such as low NO_x combustion in the process of pulverized coal combustion,at the same time,the investment in the SCR denitration device has been increased,control the amount of NO_x produced by pulverized coal during combustion with the above two measures,The generated nitrogen oxide flue gas is then purified again by a the new wet denitration technique,The NO_x fumes that eventually reach the emission standards can be discharged.Traditional wet denitration technology is simple in process,but it has low efficiency for NO removal.The new wet denitrification technology—liquid phase complex denitration technology,it sequestered transition metals and central ligands based on traditional denitration techniques,the resulting chelate has strong selective capture effect and complex removal ability for NO in the flue gas.The paper is based on previous research,removal of NO by complexation of ferrous Fe???chelate ethylenediaminetetraacetic acid?EDTA?,reduction and regeneration of saturated absorbent by sodium hypophosphite?NaH₂PO₂?.The experiment contains were described as follow.Firstly,preparation of complex denitration solution Fe???EDTA by Fe???chelate EDTA,removal NO in a bubble spray reactor with Fe???EDTA.Investigate the main effect factors of the denitration efficiency,such as reaction pH,Fe???/EDTA molar ratio,Fe???EDTA concentration and complexation reaction temperature,It show that Fe???EDTA has high removal efficiency for NO when the Fe???and EDTA in a molar ratio of 1 when the control reaction pH is 6,the Fe???EDTA concentration is 20 mmol/L,and the temperature is 303K,the removal efficiency of NO by complex solution Fe???EDTA can reach more than 82%.secondly,based on the saturation of NO absorption in the complex solution,reductive regeneration of saturated complex solution with sodium hypophosphite,Investigate the main effect factors of the denitration efficiency,such as sodium hypophosphite dosage,stirring speed and temperature.It show that,when the control reaction pH is 6,the Fe???EDTA concentration is 20 mmol/L,and the temperature is 323K,the stirring speed is 800 rpm,the amount of sodium hypophosphite is 5.28g/L,the regeneration efficiency of Fe???EDTA can reach 93%.finally,the Paper discusses total removal efficiency of NO by reductive recombination solution,Investigate the main effect factors of the total denitrification efficiency such as the pH,temperature and number of regenerations.It show that,when the pH of the regeneration complex solution for NO absorption is 6 and the temperature is 303K,the total removal efficiency of the regeneration solution for NO removal,When the complex solution is regenerated three times,the total removal efficiency of NO by regeneration solution can reach 61%.