Mass transfer behavior and desulfurization characteristics in the three-dimensional wet flue gas desulfurization tower

Wet flue gas desulfurization (WFGD) technology, recognized for the high mixing efficiency and superior SO₂ removal rate, is extensively applied in industries such as non-ferrous metal smelting and energy production. This study utilized the multiphase particle-in-cell approach and dual-film theory to elucidate the desulfurization reaction process, emphasizing gas-solid flow characteristics, lime slurry droplet dynamics, and mass transfer efficiency within WFGD towers. Utilizing a validated model, the analysis focuses on gas-solid dynamics in the desulfurization reactor and examines the effects of various operational conditions on heat transfer and desulfurization efficiency. The results indicate that lime slurry droplets with residence times ranging from 1.2 to 2.3 s are predominantly distributed throughout the desulfurization reactor. Additionally, gas temperature within the reactor decreases with increasing lime slurry droplet size, while heat exchange between the gas and slurry is most intense in the spray layer region. The mass fractions of water vapor and CaSO₃ are highest near the bottom and right wall of the system. Furthermore, the axial distribution of SO₂ concentration is primarily influenced by droplets size. Desulfurization efficiency improves with greater spray layer spacing and increased droplet quantity but decreases with higher gas velocity and larger particle size. The droplets diameter emerges as the critical factor influencing desulfurization efficiency, while the reactor inlet temperature has a minimal influence. Notably, when the lime slurry droplet diameter is reduced to less than 1 mm, desulfurization efficiency increases significantly, potentially exceeding 95 %.