Improving the removal efficiency of sulfuric acid droplets from flue gas using heterogeneous vapor condensation in a limestone‐gypsum desulfurization process

BACKGROUND: Emissions of sulfuric acid droplets have caused many problems. Improving the removal efficiency of sulfuric acid droplets is of great importance. A novel process based on heterogeneous vapor condensation was proposed in this paper to improve the removal efficiency of sulfuric acid droplets in a limestone–gypsum desulfurization process. RESULTS: The results indicated that the sulfuric acid droplets were relatively easily activated in a supersaturated vapor environment and condensed into larger droplets. The removal efficiency of sulfuric acid droplets in a wet flue gas desulfurization (WFGD) system could be significantly improved. The improvements were mainly related to the inlet flue gas moisture content and temperature. A relatively higher moisture content and lower temperature of inlet flue gas improved the removal performance. Moreover, the liquid‐to‐gas ratio and the SO₃ concentration also contributed to the improvement in removal efficiency. However, a higher temperature of the desulfurization slurry was unfavorable. CONCLUSION: The novel process based on heterogeneous vapor condensation is suitable for industrial application. The removal efficiency of sulfuric acid droplets can be improved from 30 ∼ 40% to greater than 60%. © 2016 Society of Chemical Industry