后处理厂用氮氧化物的制备实验研究

Experimental Study of Preparation Nitrogen Oxide in Reprocessing Plants

在乏燃料水法后处理的先进Purex流程中,需要利用氮氧化物对钚纯化的Pu元素调价和对2DW进行除肼,后处理厂通常采用亚硝酸钠和硝酸反应来制备氮氧化物。本论文通过对亚硝酸钠和硝酸制备氮氧化物反应的实验研究,考察了反应温度、试剂浓度、进料配比、停留时间对氮氧化物产品的影响,取得了最优的工艺参数。结果表明:在常温进料下,硝酸浓度为11 mol/L,亚硝酸钠浓度为4 mol/L,硝酸与亚硝酸钠进料配比为1.65︰1,反应停留时间为22.5 min,通入空气流量过量约50%时,生成氮氧化物中NO_(2)浓度在40%以上(体积比),收率能达到90%左右。

In the Purex process of spent fuel water treatment,nitrogen oxides are needed to oxide Pu(Ⅲ)to Pu(Ⅳ)and remove hydrazine in 2DW.Nitrous acid and sodium nitrite are generally used to prepare nitrous oxide in reprocessing plants.This paper mainly introduces the experimental study of the reaction of sodium nitrite and nitric acid to produce nitrogen oxides.The reaction temperature,reagent concentration,feed ratio and feed position were studied on the influence of nitrogen oxides.The optimal process parameters were obtained.The results show that at normal temperature whenthe concentration of nitric acid is 11 mol/L,the concentration of sodium nitrite is 4 mol/L the ratio of nitric acid/sodium nitrite is 1.65︰1,the reaction residence time is 22.5 minutes,and the air flow is about 50% through,the concentration of NO_(2) in nitrogen oxides is more than 40%(volume ration)and the yield can reach about 90%.