Influence of Key Factors on the Characteristics of Flue Gas Desulfurization of Basic Aluminum Sulfate by Bubbles

[Image: see text] Temperature, reactant concentration, bubble flow field characteristics, and mass-transfer characteristics play an important role in flue gas desulfurization of basic aluminum sulfate (aluminum base). The influence of various factors on desulfurization efficiency (η(abs)) was determined from the macroscopic and microscopic levels through experiments and numerical simulations. The temperature of absorption solution had a significant effect on η(abs), and low temperature was advantageous for SO(2) absorption performance of aluminum base. The value of η(abs) increased with increasing reactant concentration. When the aluminum base concentration was higher than 50%, η(abs) remained above 90%. The low aluminum base shortened the beginning time of the rapid decline of η(abs). This outcome was related to the low concentration of active Al(2)O(3). At a low concentration range of 2000–5000 ppm of inlet SO(2), the reaction rate determined the η(abs) level, and gas-phase mass-transfer resistance was the main factor restricting the increase in η(abs). However, reaction rate and gas-phase mass-transfer resistance determined the η(abs) level when the inlet SO(2) concentration was as high as 50 000 ppm. The aeration rate affected the bubble size, number, and diffusion state. In addition, a higher aeration rate reduced the gas–liquid contact time and speeded up the consumption of aluminum base. As a result, bubbles along the absorber height showed different desulfurization characteristics, that is, 0–0.1 m was the initial stage of bubble formation and desulfurization (the η(abs) was lower than 15%), 0.1–0.34 m was the main stage of bubble diffusion and desulfurization (the η(abs) rapidly increased to 86.4%), and 0.34–0.4 m was the stable stage of desulfurization (the η(abs) slowly increased to 92.5%).