恒容吸收系统中水和稀硝酸对NO_2的吸收过程研究(英文)

Absorption of Nitrogen Dioxide in Water and Dilute Nitric Acid Solution with Constant-Volume Absorption System

采用恒容吸收系统研究了水和稀硝酸对二氧化氮气体的吸收行为,通过测量吸收液的组成和气相压力来考察吸收剂浓度、吸收剂的量和吸收压力对NO2吸收效率和产物的影响。增加水的质量,则吸收效率增加,而所得硝酸的浓度先增加后减小。随着NO2初始压强的增加,水对NO2的吸收效率和所得硝酸浓度均增加。结果表明二氧化氮在稀硝酸中的吸收速度比在水中快,较高的气相初始压力(>90 kPa)或较高的硝酸浓度(>7wt%)都有利于吸收效率的提高。从反应关系分析计算,可获得气相组成、N2O4的转化率和HNO2的分解率等参数,发现随着水的量的增加,N2O4的转化率逐渐增大,而HNO2的分解率先增大后减小,在NO2和水的物质的量的比为0.024时达到最大值。

Absorption of nitrogen dioxide in water or dilute nitric acid aqueous solution was investigated with a constant-volume absorption system to evaluate the influence of nitric acid concentration, absorbent amount and the overall pressure on the absorption performance of NO2. With an increase in water weight, the absorption efficiencies increase, while nitric acid concentration of obtained solution rises first and then drops. With a rise in initial pressure, the absorption efficiency of NO2 in water and nitric acid concentrations both increase. NO2 is absorbed faster in the dilute nitric acid than in water. The larger initial pressure （〉90 kPa） and the higher concentration of nitric acid （〉Twt%） both lead to a significant rise of the absorption efficiency. N204 conversion and decomposition faction of HNO2 are calculated for the absorption of NO2 in water based on the results from analysis of reactions and the gas phase composition. The consumed amount of N204 gradually rises with water weight rising from 3 to 6 g, while the decomposing fraction of HNO2 first increases and then decreases. The decomposing fraction of HNO2 reaches maximum when the molar ratio of NO2 to water is 0.024.