烟气脱硫喷淋塔的数值模拟

以计算流体力学为基础,在三维坐标系下采用标准k-ε双方程模型求解动量、能量和组分方程,结合浆滴蒸发模型及简化的浆滴脱硫反应模型,以Eu ler-Lagrange方法建立了喷淋塔内烟气脱硫的数值计算模型,模型计算结果与孔华的试验数据符合较好。模型计算结果表明,对于粒径小的喷淋液滴,其烟气脱硫反应和液滴蒸发主要发生在烟气进口附近,而随着液滴粒径的增大,液滴在塔内蒸发和脱硫反应的过程延长。同时,增加烟气温度、降低烟气中SO2的入口质量浓度以及增加液气比均有利于提高脱硫效率。文中模型相对于一维柱塞流模型,能够直观地显示出喷淋塔内的流场、温度场和组分质量浓度场的空间分布。

Numerical simulation of flue gas desulphurization by spray tower

Based on computational fluid dynamics,a numerical calculation model for a spray tower was established by employing an Euler-Lagrange approach in a three-dimensional coordinate system.Momentum,energy and composition equations of slurry-droplet desulphurization were solved with the help of standard kε dualequation models in connection with evaporation and a simplified desulphurization reaction model.The simulated data was in a good accordance with the experimental data.The simulated data shows that the droplets evaporation and the desulphurization reaction mainly occur near the inlet of the tower to the smaller droplets.With increasing the diameter of droplets,the process of the droplets evaporation and the desulphurization reaction was extended.Meanwhile,the degree of desulphurization would be improved by raising the gas temperature,reducing the inlet SO2 concentration and increasing the slurry/gas ratio.Relative to the one-dimensional plug-glow model,the model under discussion could visually display the flow field,temperature field and spatial distribution of constituent element in the spray tower.