氨法脱硫工艺S(IV)氧化动力学模型研究

目前,有关氨法脱硫技术对S(IV)氧化的研究未考虑HSO-3及离子强度等因素的影响.因此,本文根据氨法脱硫反应机理建立实验装置对S(IV)氧化动力学进行了研究,考察了SO2-3浓度、SO2-4浓度、pH值、温度和氧化空气量对S(IV)氧化速率的影响.结果表明,S(IV)的氧化速率与SO2-3浓度呈-0.5级关系,与SO2-4浓度之间的关系为r(IV)=0.00121exp(-0.89CSO2-4);HSO-3较SO2-3更容易被氧化,保持较低pH值时对S(IV)的氧化有利;S(IV)的氧化速率随氧化空气量和温度的升高而增大,反应的表观活化能约为28.0 kJ·mol-1.利用数学模型对S(IV)氧化过程进行了数值模拟,结果表明,该模型能够较好地反映氨法脱硫S(IV)氧化过程.

An oxidative kinetic model of total sulfite in ammonia-based wet flue gas desulphurization process

Previous studies regarding oxidation of total sulfite in ammonia-based desulphurization process has not taken the effects of bisulfite and ionic strength, etc. into account. Experimental apparatus were set up to study the effects of SO₃^2-concentration,SO₄^2-concentration, pH, temperature and amount of air on the oxidative kinetics of total sulfite. The experimental results show that the oxidation rate of total sulfite is -0.5 order with respect to sulfite, and its relationship with SO₄^2-concentration is,r_(IV)=0.00121exp(-0.89C₄SO^2-) with bisulfite more easily oxidized than sulfite. Therefore, keeping low pH level of the solution is conducive to the oxidation of total sulfite. The oxidation rate of total sulfite increases with air amount and temperature. The apparent activation energy for the overall oxidation is calculated to be 28 kJ·mol^-1. A mathematical model was developed to simulate the process of oxidation of total sulfite and the calculated results show that this model agrees well with the experimental results of oxidation of total sulfite.