基于CFD技术的镁法脱硫塔入口烟道流场优化分析

摘要

以某300 MW机组镁法脱硫塔为研究对象,针对入口烟道内存在的气流冲壁现象,利用计算流体动力学软件Ansys13.0,对其进行了流场数值模拟.塔内烟气采用Reynolds时均Navier-Stokes方程描述,离散相采用拉格朗日模型描述.通过对布置不同导流板的方案分析表明,在烟道内布置若干数量的导流板,可以有效地缓解入口烟道内壁的气流冲刷现象;同时导流板的布置使得塔内烟气流场分布更加均匀,气液两相混合更的均匀,并提高了吸收效率.综合考虑入口导流板数量以及塔内流场分布,布置三块导流板最为合理;另外针对入口处布置不同数量导流板的模拟结果对镁法喷淋塔的现场运行以及结构优化提供理论依据.%Taking the magnesium 300MW units desulfurization scrubber as an object of study,to solve the entry of scouring wall by the gas stream,numerical simulation was carried out with computational fluid dynamics theory and Ansys13.0 software.The turbulent flow of gas in the scrubber was described by Reynolds-averaged Navier-Stokes equations,and the discrete phase was described by Lagrangian discrete phase model.Through the arrangement of the different options of the deflectors showed that compared with the original scrubber,by arrangement of different deflector in the entry section,gas stream scouring in the entry section was effectively weakened;Meanwhile,flue gas flow field distribution in scrubber was more uniform by arrangement of deflector,the gas and liquid could contact with each other more sufficiently,and Increase the absorption efficiency.Considering the flow distribution in the entry section and scrubber,the arrangement of three deflectors was the most reasonable option.As a result,references and advices were given to site operation and optimization of magnesium desulfurization scrubber.