Abstract: Wet limestone scrubbing is the most common flue gas desulfurization process for control of sulfur dioxide emissions from the combustion of fossil fuels, and forced oxidation which belongs to gas-liquid transfer process is a key path of the reaction.In the present work,the two-film theory was used to analyze the sulfite forced oxidation reaction with an image boundary recognition technique and the oxidation rate was experimentally studied by contacting pure oxygen with a sodium sulfite solution.There was a critical sulfite concentration 0.328 mol•L^-1 without catalyst or at a steady catalyst concentration.When the Co²⁺ catalyst concentration was kept unchanged, the sulfite oxidation reaction rate was controlled by dual film and the reaction kinetics was first order with respect to sulfite while SO^2-₃ concentration was below 0.328 mol•L^-1.The sulfite oxidation reaction rate was controlled by gas film only and the reaction was zeroth order with respect to sulfite while the SO^2-₃ concentration was over 0.328 mol•L^-1.When SO^2-₃ concentration was kept unchanged, the sulfite oxidation reaction rate depended on gas-liquid mass transfer and the reaction kinetics was different in various stages with respect to Co²⁺ concentrations.

Key words: 传质, 动力学, 氧化速率, 临界浓度

摘要： 在湿法烟气脱硫的过程中，吸收塔底部发生的反应主要是亚硫酸钙和空气或氧气之间的气液传递与化学反应过程，根据双膜理论模型，分析了该反应的吸收机理，用一种图像边界识别的方法分析亚硫酸盐强制氧化气液反应.在没有催化剂或固定钴离子催化剂浓度时，SO^2-₃存在临界浓度0.328 mol•L^-1.当SO^2-₃的浓度低于0.328 mol•L^-1时，过程为双膜控制，SO^2-₃的反应级数为1;当SO^2-₃的浓度大于0.328 mol•L^-1时，过程逐渐变为气膜控制，SO^2-₃反应级数为0.当固定SO^2-₃浓度时，催化剂钴离子的反应级数则受到气液传质的影响，分为几个阶段，且反应级数不同.

关键词: 传质, 动力学, 氧化速率, 临界浓度