VOC吸收塔内传质性能CFD的初步模拟

CFD Preliminary Simulation of Mass Transfer Performance in VOC Absorption Tower

挥发性有机化合物(VOC)脱除是气体净化的难题和热点。油基吸收方法获得了较好脱除效果(特别对焦油类VOC),但吸收塔内热质传递过程复杂,耦合传质过程的CFD可视化模拟尚不多见。选取苯和甲苯作为VOC模拟物,将实测体积吸收系数作为质量源项导入Fluent模型,模拟探索吸收塔内流动和传递特性。结果表明,模拟得到VOC脱除率与实测值相对误差为11%~16%。塔内具有较好的热质传递效果,VOC浓度自下而上逐层降低;同一水平高度中心位置的VOC浓度要低于近壁面处,壁面处传质效果有待改善;单位高度传质效果较为均匀,塔上部由于浓度梯度下降,略有下降。

VOC removal is hot and difficult problem in gas purification field.The method of oil washing is effective,but the process of heat and mass transfer is complicated in the absorption tower,and the simulation of absorption tower by CFD visualization is rare.Benzene and toluene are selected as VOC simulation materials,and the mass transfer coefficient which is measured by previous experiment is introduced to fluent as mass source to explore flow field and mass transfer characteristics.The results show that the deviation of VOC removal rate between simulation and experiment is 11%~16%.The heat and mass transfer effect are better than that in the tower,and VOC concentration decreases from bottom to top.VOC concentration at the center of the same level is lower than that near the wall,and mass transfer coefficient needs to be improved.The mass transfer effect of per unit height was relatively uniform,and the VOC concentration upper part of the tower decreased slightly due to the concentration gradient.