亚硫酸铵浓度对亚硫酸铵氧化速率的影响研究

Influence of ammoniac sulfite concentration on its oxidation rate

亚硫酸铵氧化是铵法脱硫的一个重要步骤,针对工程上主要采用的空气氧化方法,开展了在空气氧化条件下亚硫酸铵浓度对亚硫酸铵氧化速率的影响规律研究。试验采用空气鼓泡氧化反应器,在控制空气流量和反应温度不变的条件下,研究了亚硫酸铵氧化速率随亚硫酸铵浓度的变化关系。结果表明：在中、高浓度范围（〉0.1 mol/L）内,氧化速率受浓度影响不大,可认为无变化,在此过程中空气曝气流量是氧化反应的主要控制因素;在较低浓度范围（0.01~0.1 mol/L）内,氧化速率与浓度为斜率较小的线性关系;而在极低浓度（〈0.01 mol/L）下,氧化速率与浓度为斜率较大的线性关系,即当浓度低于0.1 mol/L时,亚硫酸铵氧化反应速率明显受亚硫酸铵浓度的影响。

This paper is inclined to introduce the results of our investigation and exploration on the ammoniac sulfite oxidation. As is known, the ammonium desulphurization tends to give out by-products named ammoniac sulfite, and the oxidation of the ammoniac sulfite has been a hot spot in the modem desulfurization industry. What is more, the efficiency of converting the ammoniac sulfite into ammoniac sulfate dominates the industrialized use of ammonia desulphurlzation. It is just for this reason that we have done the air bubble experiment to examine the features of ammoniac sulfite oxidation rate, in which our research results are in a position to provide a theoretical basis for its industrial application. What is more, the results of our experi- ments also demonstrate that, on the condition when the temperature and the aeration flow remain unchanged, the initial concentration of the ammoniac sulfite can be shown as follows： 0.01 mol/L, 0.04 mol/L, 0.09 mol/L, 0.4 mol/L, 1.0 mol/L, 1.4 mo//L, 1.7 mol/L and 1.9 mol/L. And, then, when all the experimental results were summarized and analyzed in a systematic record, it has become clear that the relation between the ammoniac sulfite concentration and the oxidation rates can be shown in the following three forms. That is to say, when the concentration of the ammoniac sulfite is above 0.1 mol/L, the oxidation rate should be taken as a constant, in which the concentration of the ammoniac salfite is high, with the control factor and the aeration flow being the same. However, other researchers tend to draw different conclusions from the above said experiment. For example, when the concentrations of the ammoniac sulfite range from 0.01 mol/L to 0.1 mol/L, a linear relation can be found with a smaller slope between the oxidation rate and the concentration from the diagram. But, when the concentration is below 0.01 tool/L, the !inear relation tends to be with a greater slope. Nevertheless, of the last two forms, the oxidation rate wouldn＇ t be affected by the aeration flow. However, when the concentration of the ammoniac sulfite is low, the control factor may include the ammoniac salfite concentra- tion, with the oxidation rate of its low concentration being higher. Further investigations into the data let us gain the quantitative results. That is to say, when the ammoniac sulfite concentration is above 0.1 mol/L, the oxidation rate ＂y＂ （ % ） should also be a constant. But, when the concentration ranges from 0.01 mol/L to 0.1 mol/L, the relation between the oxidation rate ＂y＂ （ % ） and the concentration ＂x＂ （mol/L） turns out to be an equation： y - 6.47214x ＋ 0.81626, R2 = 0.820. Nevertheless, when the concentration is be- low 0.01 mol/L, the relation should be represented in： y = 90.48175x - 0.04558, R2 = 0.855. Thus, the findings are exclu- sively accessible for the given experiment we have done. In spite of this, further research is needed to test and prove the universality of the conclusion.