湿法烟气脱硫流场优化数值模拟与模型试验研究

Numerical simulation and model experimental research on optimizing the flow field in wet flue gas desulfurization

流场是影响湿法烟气脱硫吸收塔脱除SO_2效果的关键因素,为了达到超低排放标准要求,对湿法脱硫吸收塔流场优化至关重要。采用CFD方法对某燃煤电厂2×660 MW机组湿法脱硫吸收塔优化前流场进行数值模拟研究,分析优化前吸收塔流场存在的问题,之后对吸收塔流场进行优化。优化方案在吸收塔进口烟道和出口烟道布置导流板、在吸收塔内布置多孔分布器可使吸收塔流场得到显著改善,有利于提高脱硫效率、减小烟道浆液沉积和降低烟道阻力。根据流体力学相似理论,搭建缩小比例吸收塔模型进行流场试验,试验速度分布均匀性与数值模拟结果相近,验证了流场优化方案的可行性,能为吸收塔设计提供指导作用。

Flow field is a key factor affecting the removal efficiency of SO2 from wet flue gas desulfurization absorption tower.In order to meet the requirements of ultra-low emission standards,the flow field optimization of wet desulfurization absorber is of great importance.The CFD method is applied to simulate the flow field of a wet desulfurization absorber for a 2 × 660 MW unit in a coal-fired power plant.The existing problems of the flow field in the absorber before optimizing are analyzed,and then the flow field is optimized.In the optimization scheme,flow guiding vanes are set in the inlet and outlet flue ducts,and a porous flow distributor is set in the tower.The flow field has been significantly improved after optimizing,which is conducive to improve the desulfurization efficiency,reduce slurry deposition and decrease flow resistance.Based on the similarity theory of fluid mechanics,a model of reduced proportion absorption tower is built to carry out flow field experiment.The velocity distribution uniformity of the experiment is similar to that of numerical simulation.The feasibility of the flow field optimization scheme is verified,and it can provide guidance for the design of absorption tower.