Abstract: To predict the slurry temperature in wet flue gas desulfurization(WFGD)system, a concept of insulation saturation temperature of wet flue gas was put forward, and the functional relationship between slurry temperature and inlet flue gas temperature and moisture content was deduced. Based on the predicted slurry temperature, a 1-D coupled mathematical model of droplets motion, heat and mass transfer and pressure loss of liquid-gas two phases was established, the influence of three-dimensional inhomogeneity of desulfurization system on model accuracy was analyzed. In terms of the main operating variables in desulfurization system(diameter of slurry particle, inlet temperature of flue gas and ratio of liquid to gas), the 1-D distribution law of the related parameters was obtained by the Runge-Kutta iteration method. In order to verify the model, the field test and physical model test were carried out respectively. The results showed that the predicted slurry temperature was in good agreement with the measured parameters, the maximum error was 4.56%; the diameter of slurry particle was the main factor affecting heat and mass transfer; the velocity of particles decayed rapidly in the process of decline, and tended to the final invariant value; the temperature of the flue gas was distributed exponentially with the height of the tower. Compared with the predicted values, the maximum errors of temperature and pressure distribution from the experimental results were 4.72% and 6.46% respectively. The model had high accuracy, which was of guiding significance to the design, operation and study on mass transfer of SO₂ in WFGD system.

Key words: wet flue gas desulfurization, praying tower, heat and mass transfer, adiabatic saturated temperature, slurry temperature