空气氧化解吸NO络合吸收产物试验研究

Experiment on the desorption of NO chelate absorption product by air oxidation

Fe(Ⅱ)EDTA易被氧化为对NO无吸收能力的Fe(Ⅲ)EDTA,为实现Fe(Ⅱ)EDTA的循环使用,提出了Fe(Ⅱ)EDTA络合吸收-空气氧化解吸-铁屑还原再生组合脱除NO新工艺。采用空气氧化解吸络合吸收产物Fe(Ⅱ)EDT、A(NO)中NO的方法,研究了温度及压力对Fe(Ⅱ)EDTA(NO)空气氧化解吸过程的影响。结果表明,0.4 MPa、333K为较优的解吸条件。该工艺可循环脱除NO,成本低、效率高,能有效回收NO_2资源。

The paper is inclined to propose a new method for regenerating NO absorption products from Fe（Ⅱ）EDTA complex process,in which Fe（Ⅱ）EDTA（NO） was desorbed through air oxidation,and Fe（Ⅲ）EDTA was reduced by Fe powder.In proceeding with our experiment,we have laid out a simulated experiment of recovery wet flue gas denitration with Fe（Ⅱ）EDTA in the laboratory condition.As a result of our experiment and analysis we have found it would be possible to make the absorption efficiency of Fe（Ⅱ）EDTA as high as over 95%,under the conditions of the initial Fe（Ⅱ）EDTA concentration of 15 mmol/L,the temperature of 333 K and pH value of 6.In accordance with our experimental experience,it recommended to conduct NO desorption from Fe（Ⅱ）EDTA（NO） via the air oxidation in a pressurized reactor.To identify all the participating influential factors,we have explored such affecting factors,as temperature and air pressure.The results we have gained from the experiments can be stated as follows：Fe（Ⅲ） concentration,which can demonstrate the desorption efficiency,proves to be increasing with the increase of temperature.In addition,the process of NO desorption is an endothermic one by nature.What is more,as the air pressure goes up,the O2 gas-liquid mass transfer tends to increase,which turns out propitious for the oxidation of Fe（Ⅱ）.Afterwards,Fe（Ⅲ） EDTA can be effectively reduced to Fe（Ⅱ）EDTA with the help of 0.8 g iron powder in a stirred tank at 333 K and a stirring rate of 600 r/min.And,eventually the absorbing efficiency of NO by regenerated Fe（Ⅱ）EDTA complex can reach more than 95%,which is close to the optimal effect of fresh complex.In so doing,the denitration can be made promising to go on at a high and confident efficiency.Thus,it can be predicted that this complex process can not only help to remove NO effectively at a low expense but also obtain high concentration of NO2.