伞罩型除尘脱硫塔内除雾器性能研究

Study on characteristics of demisters in dedusting and desulphurization tower with umbrella plates

除雾器是湿法烟气脱硫(WFGD)系统内重要的设备之一,其性能对WFGD系统运行的可靠性有重要影响。利用Fluent6.2软件对新型伞罩型除尘脱硫塔内的三维两相流场进行数值模拟,气相采用RNG湍流模型,液相采用离散相模型,选择SIMPLE算法进行计算,分析塔内的折板除雾器和旋流板除雾器的速度场、压力场和液滴的分布情况。结果表明,烟气经过折板除雾器,产生了明显的压降,且在拐角区域湍流耗散强烈,是实现气液分离的关键区域;烟气经过旋流板除雾器,速度和压强分布具有良好的对称性,液滴被气流旋转抛向壁面实现气液分离。模拟结果对新型的WFGD除雾器的设计和运行具有一定的理论指导意义。

Demister is one of the key equipment in the wet flue gas desulphurization （WFGD） system. Its performance is of great importance to the reliable operation of WFGD system. In this work, the RNG turbulence model and Discrete Phase Model （DPM） were used to simulate the 3-D two-phase flow in the new WFGD with umbrella plates by using Fluent6.2 package and SIMPLE algorithm calculation method. Velocity field, pressure field and distributions of liquid drops in demisters with serrated baffles and rotated-stream trays in the tower were analyzed. The results showed that the pressure declined obviously when flue gas flowed through the demister with serrated baffles, where turbulent dissipative was very intense at corner regional, which would be beneficial to separation of gas and liquid. Both the gas velocity profiles and total pressure distributions were well axial symmetric when flue gas passed by the demisters with rotated-stream trays, which the liquid drops were revolved and threw toward wall surface by flue gas to carry out gas-liquid separation. Simulation results will be helpful in the design and operation of the demisters in the new WFGD.