Prediction and Experimental Validation Studies of Wet Flue Gas Desulphurization with a Novel Type PCF Device Based on Limestone-Gypsum

Abstract

A novel wet-type flue gas desulphurization process were developed and tested in this study. The process used a PCF device as the absorber where SO2 was absorbed into slurry of reactive CaCO3. A model of external mass-transfer based on the two-film theory was proposed for estimation of the SO2 absorption in the PCF device, and the theoretical SO2 removal efficiency was compared with the experimental data. The results show that the SO2 absorption rate in the spray zone is controlled by a combination of gas- and liquid-film diffusions in the range of tested operating conditions. The increase of gas flow rate and droplet size and decrease of liquid−gas ratio all can lead to a decrease in the SO2 removal efficiency. Addition of Cl− to the slurry (25 g/L) decreases the SO2 removal efficiency from 83.87 to 70.75%. when comparing the results of prediction and experiment, the data show good agreement. With droplet size equal to 2500 μm, when gas flow rate and liquid−gas ratio are changed, the relative errors of SO2 removal efficiency between the predicted and experimental data are below 3.40 and 8.67%, respectively. It demonstrates that the model proposed in the present study is an effective model to evaluate and predict the desulphurization performance of the novel type PCF device. Moreover, the theoretical model can be extended to apply in other wet FGD technologies.