磷矿浆催化氧化湿法脱硝研究

采用液相催化氧化NO_x的方法,通过磷矿浆中过渡金属离子的催化作用,达到净化电厂烟气中NO的目的。考察了烟气含氧量、吸收温度、磷矿浆固液比及气体流量对磷矿浆湿法脱硝的影响。结果表明,试验最佳条件为NO进口质量浓度670 mg/m~3、磷矿浆吸收温度25℃、固液比500 g/L、流量0.3 L/min、含氧量20%;优化条件下的磷矿浆脱除效率最高可达88.9%。随着磷矿浆湿法催化氧化脱硝反应的进行,p H值不断下降,导致磷矿浆逐渐失效,需补入新鲜矿浆,维持吸收液的p H值以保证良好脱硝率。

Experiment study on catalytic oxidation of phosphate ore pulp to wet denitrification

The paper is engaged in a study of the catalytic characteristics of the transition metal ions,which are prone to result in the complexes with foreign ions and molecules,for the phosphate ore pulp is abundant in the transition metal ions under the condition of acidic property.To identify and determine the catalytic features of the transition metal ions,we have done the experiment with the reaction of the catalytic oxidation low-concentrated NO by phosphate ore pulp as the absorption liquid,and the low concentrated NO flue gas from the power-generating plant through simulated static state method,while using a glass sand absorption reactor as the tail gas absorption tower in the said plant.What is more,we have also investigated a series of factors affecting the concentration of NO at the outlet and NO removal efficiency,including the oxygen content,the absorption temperature,the solid liquid ratio of the phosphate ore pulp to the gas flow.The results of our experimental study show that while the reaction is going on,the denitrification rate of the phosphate ore pulp tends to increase significantly as the oxygen content is rising.It has also been found that the denitrification rate tends to continue to increase even when the absorption temperature drops.Of course,it tends to increase first and then decrease in pace with the gas flow and the solid liquid ratio.Moreover,under the optimum condition when the inlet NO mass concentration were to be 670 mg/m3 and the oxygen content were to be 20％,the absorption temperature were to be 25 ℃C,the solid liquid ratio were to be 500 g/L,and the gas flow were to be 0.3 L/min,the denitrification rate may likely exceed 80％.And,furthermore,with the increase of the reaction time-length,pH value may tend to decline from 7.18 to 4.2,with the denitrification rate falling to 78.6％.Nevertheless,more fresh phosphate ore pulp is needed to raise pH value so as to obtain a good denitrification rate.Thus,as compared with the traditional denitrification technologies,it proves that the phosphate ore pulp is not only exceptionally available,but also highly effective.Therefore,the pulp denitrification is in a position to provide for an efficient and economic method to remove the low concentrated NO.