Numerical Simulation Of Flow Field In Ammonia-Based Wet Flue Gas Desulfurization Tower

At present, ammonia-based wet flue gas desulfurization technology has been widely used, how to improve the desulfurization efficiency has become a hot research on the basis of reducing operation costs. The theme of the paper is discussion on a desulfurization spray tower. The main factors affecting the desulfurization efficiency are analyzed. It is pointed out that the uniformity of flow field distribution have a significant impact on desulfurization efficiency. Meanwhile, the optimization simulation on the structure and the operation parameters of the desulfurization tower is carried out with CFD software. Combine with speed characteristics, temperature characteristics and resistance characteristics, comparison of the flow field characteristics in the tower under different conditions are made, finally the best optimization solution is determine.The simulation results show:(1) With the increase of the flue gas entrance angle, it helps to improve the desulfurization efficiency, but the pressure drop will increase, and not conducive to the economic, so the entrance angle of 15 ° is more reasonable.(2) With the increase of diameter-height ratio, uniformity of the flow field in the tower will decrease, while decreasing the diameter-height ratio, residence time of the flue gas will reduce, and not conducive to desulfurization efficiency, considering, it is advisable to choose the diameter-height ratio about 0.463 for the tower.(3) The fluctuation of the inlet flue gas load has a bigger influence on the flow field in the tower.(4) The slurry droplets have a rectifier effect on the flow field of the tower, and the phenomenon of flue gas rushing wall almost disappear without spraying. Considering the view of desulfurization efficiency and economic, the three spray is suitable for 100% inlet flue gas load; the higher spray is suitable for 80% inlet flue gas load; the high-low combination spray is suitable for 60% inlet flue gas load.(5) The spray angle should be 120° overall considering the effect of liquid film and operation condition in the tower.(6) The change of the flue gas inlet temperature has no influence on the uniformity of flow field distribution and the loss of pressure in the tower, and the higher the flue gas inlet temperature is, the faster the temperature decrease.(7) Within a certain range, increasing liquid-gas ratio can contribute to film coverage, heat transfer, mass transfer and desulfurization efficiency. At the same time, from the perspective of the economic, the liquid-gas ratio of this system at 6L / m3 was more appropriate. Numerical investigation can guide the desulphurization system operation to reach optimal economical mode.