Tang Zuozhou, Li Zhongwei, Ji Bingqiang, Song Qiang
Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China.
School of Astronautics, Beihang University, 100191 Beijing, China.
ACS Omega. 2025 May 5;10(19):19625-19635. doi: 10.1021/acsomega.5c00382. eCollection 2025 May 20.
SO in coal-fired flue gas causes equipment corrosion and sulfuric acid mist emissions. As the flue gas temperature decreases, SO converts to gaseous HSO and condenses with HO via binary heterogeneous condensation. Here, based on thermodynamic equilibrium theory, a model for HSO-HO binary heterogeneous condensation is developed and verified by comparing the calculated planar acid dew point ( ) with the previously reported experimental data. The equilibrium parameters of condensation on both planar and particle surfaces are investigated. On planar surface, increases with the gas concentration, while the equilibrium sulfuric acid mass fraction ( ) increases with HSO concentration and decreases with HO concentration. For HSO concentrations of 0.5-50 ppm and HO concentrations of 0.5%-15%, ranges from 356.37 to 426.67 K and the equilibrium sulfuric acid mass fraction ( ) ranges from 71.922% to 91.058%. The equilibrium parameters on micrometer particle surfaces are similar to those on planar surfaces, while on submicrometer particle surfaces, the acid dew point ( ) decreases and the equilibrium liquid film sulfuric acid mass fraction ( ) increases with decreasing particle diameter ( ) due to the Kelvin effect. We found that / and ω/ω are barely unaffected by and can be considered as a function of . Based on the numerical results, formulas with good prediction accuracy for and are proposed. The results provide predictive models for acid dew points on particle surfaces, which are crucial for guiding strategies to mitigate corrosion and reduce sulfuric acid mist emissions in coal-fired power plants.
燃煤烟气中的SO会导致设备腐蚀和硫酸雾排放。随着烟气温度降低，SO转化为气态HSO，并通过二元非均相冷凝与HO冷凝。在此，基于热力学平衡理论，建立了HSO-HO二元非均相冷凝模型，并通过将计算得到的平面酸露点（ ）与先前报道的实验数据进行比较来验证该模型。研究了平面和颗粒表面上冷凝的平衡参数。在平面表面上， 随气体浓度增加而增加，而平衡硫酸质量分数（ ）随HSO浓度增加而增加，随HO浓度降低而降低。对于0.5 - 50 ppm的HSO浓度和0.5% - 15%的HO浓度， 范围为356.37至426.67 K，平衡硫酸质量分数（ ）范围为71.922%至91.058%。微米级颗粒表面的平衡参数与平面表面相似，而在亚微米级颗粒表面，由于开尔文效应，酸露点（ ）随颗粒直径（ ）减小而降低，平衡液膜硫酸质量分数（ ）增加。我们发现 / 和ω/ω几乎不受 的影响，可视为 的函数。基于数值结果，提出了对 和 具有良好预测精度的公式。研究结果为颗粒表面酸露点提供了预测模型，这对于指导燃煤电厂减轻腐蚀和减少硫酸雾排放的策略至关重要。
