燃煤烟气中SO₃ 的生成与排放严重威胁着电厂的安全经济运行与大气环境，本文探究了K₂CO₃、Na₂CO₃ 与Ca(OH)₂三种碱基吸收剂对SO₃ 的脱除性能及速率控制机制。结果表明，吸收剂对SO₃ 脱除性能为K₂CO₃>Na₂CO₃>Ca(OH)₂，温度与化学当量比的增加均有利于SO₃ 的脱除。随着SO₃ 脱除反应的进行，吸收剂表面形成的硫酸盐覆盖物会影响SO₃ 向未反应界面的扩散，导致反应速率下降。SO₃ 脱除反应速率受外扩散过程控制，但在Na₂CO₃ 与Ca(OH)₂ 脱除SO₃ 的反应后期，反应速率由外扩散与内扩散共同控制。

The generation and emission of SO₃ in coal-fired flue gas seriously threaten the safe and economic operation of power plants and the atmospheric environment. The removal performance and rate control mechanism of SO₃ by three alkaline absorbents, K₂CO₃, Na₂CO₃, and Ca(OH)₂, were investigated in this study. The results show that the SO₃ removal performance of the absorbent is K₂CO₃>Na₂CO₃>Ca(OH)₂, and the increase of temperature and stoichiometric ratio is beneficial to the removal of SO₃. With the process of reaction, the sulfate coating formed on the surface of the absorbent will affect the diffusion of SO₃ to the unreacted interface, resulting in a decrease in the reaction rate. SO₃ removal reaction rate is controlled by external diffusion. For the absorbents of Na₂CO₃ and Ca(OH)₂, the reaction rate in the later stage of the eaction is controlled by both external diffusion and internal diffusion.