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A dynamic model for the flue gas desulfurization tower in coal-fired power plants is proposed. The model is validated with the data from a 350 MW unit. The penetration theory is adopted in modeling. The movement and the size of the slurry droplets, the temperature and the flow rate of the flue gas, as well as the chemical reactions have been taken into account. Three parameters in the model are found to have a critical impact on the model accuracy, i.e., the droplets' initial velocity, the number of droplets leaving all nozzles in a single spray layer per unit time, and the liquid side mass transfer coefficient of sulfur dioxide. These parameters need to be identified periodically in real applications. The quantitative relationship between pH and liquid side mass transfer coefficient is given. The main hypotheses and parameters of the model were discussed in order to quantify their respective influence. The model may be used to simulate the desulfurization process across the entire load range. Specifically, it may be used to predict the desulfurization efficiency online, so that applied potentially for the operational optimization. [ABSTRACT FROM AUTHOR]

Effects of the sieve plate on hydrodynamics and mass transfer in an annulus sparged airlift reactor (0.08 m³ 1.3 m tall, and 0.284 m in diameter) were investigated. It is found that the sieve plate can significantly enhance gas holdup and volumetric mass transfer coefficient. The sieve pore plays an important role in breaking up bubbles. With a given free area ratio, the sieve plate with a larger sieve pore diameter is more efficient in increasing the volumetric mass transfer coefficient. Four different free area ratios between 37% and 73% are tested, and then an optimal free area ratio is determined. The effect of the sieve plate is found to be related to sparger types. The sieve plate leads to a larger increase of volumetric mass transfer coefficient with the O-ring distributor as compared to the 4-orifice nozzle. Empirical correlations and a hydrodynamic model are proposed to predict gas holdup, volumetric mass transfer coefficient and liquid velocity in airlift reactors with sieve plates. [ABSTRACT FROM AUTHOR]