Abstract: The efficiency of sulfite oxidation is a key factor affecting system performance in wet flue gas desulfurization (WFGD) of coal-fired power plants. However, current WFGD systems lack accurate indicators for controlling the sulfite oxidation process. To clarify the principles and methods of oxidation control, and to understand how high-salinity environments influence system oxidation states, this study employed a bubble column reactor to investigate the oxidation of calcium sulfite. From the perspective of reactive absorption and mass transfer kinetics, the study proposed the Hatta number (Ha) as a viable indicator for regulating oxidation states. The forced oxidation of sulfites by air was actually a process in which O2 was transferred from the gas phase to the liquid phase and reacts with sulfites. To analyze the characteristics of Ha in the reactive absorption system of O2, the study first evaluated physical mass transfer coefficients of O2 under varying air flow rates and NaCl concentrations. The reaction order between SO_3^(2-) and O2 was determined to be 0.863, with a reaction rate constant of 3.164. A normalized analysis under saline conditions was conducted to explore four key physical parameters (liquid diffusivity D, ion activity coefficient γ, gas-liquid contact area α, and saturated dissolved oxygen mass concentration DO*). The results showed that the ion activity coefficient is the primary pathway through which NaCl addition interferes with Ha. Based on the three-stage mechanism of reactive absorption, a feedback control strategy using Ha as the core indicator was proposed. This strategy enabled simultaneous assessment of oxidation status and dynamic adjustment of blower air volume. When implemented in the experimental system, the strategy increased O2 utilization by a factor of 5.76, and the time to reach 95% sulfite oxidation was only delayed by 200 seconds.

Key words: oxidation, kinetics, Hatta number, NaCl, feedback regulation

摘要： 火电厂湿法脱硫过程中亚硫酸盐氧化效果是决定系统运行效果的关键一环，当前湿法脱硫缺乏准确的指标控制亚硫酸盐氧化。为明确氧化控制原理与方法，解释电厂高盐环境系统氧化状态的影响，本工作搭建了鼓泡反应器研究亚硫酸钙氧化过程，从反应吸收传质动力学角度提出了Hatta数(Ha)作为指标控制调节氧化状态。亚硫酸盐被空气强制氧化实际是O2从气相转移至液相并与亚硫酸盐反应的过程，为了解析O2反应吸收体系内Ha数值特性，围绕过程中的物理传质与化学增强路线，首先计算了不同空气流量与NaCl质量浓度的O2物理传质系数，并给出了SO_3^(2-)与O2反应级数(0.863)与反应速率常数(3.164)；进而通过含盐条件的归一化分析，对比四项关键过程物理参数包括：液相扩散系数D、离子活度系数γ、气液接触面积α及饱和溶解氧质量浓度DO*，发现了NaCl添加干扰Ha的主要路径是离子活度系数。根据反应吸收的三个阶段，提出了基于Ha的氧化风机反馈调节策略，同步实现氧化状态判断与氧化风量调整。将反馈调节策略应用于本次实验系统后，O2利用率提高了5.76倍，SO_3^(2-)氧化率达到95%的时间延迟了200 s。

关键词: 氧化, 动力学, Hatta数, NaCl, 反馈调节