Structural optimization and flow field simulation of gas distribution device in desulfurization tower

In order to comply with ultra-low emission requirements and further reduce the concentration of SO2 emissions from coal-fired power plants, a novel distributor has been proposed to enhance the uniformity of fluid distribution in the desulfurization tower. The distributor ensures that the inlet flue gas comes into even contact with the slurry droplets ejected from the nozzle, thereby improving the removal efficiency of SO2. The research focuses on a circular desulfurization tower using ammonia-based desulfurization. To study the enhancement of non-empty tower desulfurization efficiency, a CFD-DPM model based on the Euler-Lagrange method has been established. The accuracy of the model has been verified through comparison with experimental or validated data, ensuring its reliability in predicting the performance of the proposed distributor in enhancing desulfurization efficiency in the circular desulfurization tower. The simulation results demonstrate that the addition of the new inflow gas distributor leads to a significantly thinner flue gas escape zone in the circular desulfurization tower. The flue gas flow velocity at the wall side of the tower, above the distributor, increases by only about 1 m/s with the rise of the horizontal cross section, and there is hardly any flue gas escape zone observed. The addition of the distributor increases the pressure drop in the local area, while optimizing the flow field in other areas and reducing the turbulent dissipation energy, which in turn reduces the full tower pressure drop from 701 to 474 Pa. Additionally, the flue gas at the outlet of the distributor is uniformly dispersed, with gas velocity distribution unevenness values of 0.558, 0.587, and 0.601, respectively, which are 15.9%, 14.0%, and 14.0% lower than the unevenness value of the empty tower spraying, at a depth of 1 m below each spray layer. These improvements in gas flow distribution and pressure drop contribute to better control of ammonia escape and aerosol phenomenon, while also enhancing the desulfurization efficiency.