喷淋层组合方式对大型脱硫塔内流动和热湿交换过程影响的数值模拟  

Numerical simulation of impact of spraying layers scheme on gas-liquid two phases flow, heat and mass transfer in large scale desulphurization absorption tower

作　　者：林瑜 陈德珍[2] 尹丽洁 LIN Yu;CHEN Dezhen;YIN Lijie(Honeywell R&D Center, Shanghai 201203, China;Institute of Thermal and Environmental Engineering, Tongji University,Shanghai 200092,China)

机构地区：[1]霍尼韦尔中国研发中心,上海201203 [2]同济大学热能与环境工程研究所,上海200092

出　　处：《中南大学学报（自然科学版）》2017年第10期2572-2582,共11页Journal of Central South University:Science and Technology

基　　金：国家高技术研究发展计划(863计划)项目(2012AA063504)~~

摘　　要：采用计算流体力学方法对大型脱硫塔内的喷淋层(共4层)组合方案进行数值模拟。通过欧拉-拉格朗日方法,充分考虑气液两相间的动量、质量和能量交互作用,同时把气相湍流脉动对离散相轨迹的影响也考虑在内,从而获得喷淋层变化时塔内的气液两相流动和热湿交换规律,并与现场数据作对比。研究结果表明:仅底层喷淋时,在吸收塔入口左上方,气相有较大的漩涡区。而仅顶层和多层喷淋时,上述流场不均匀性得以消除。喷淋层数越多气相压损越大;仅顶层喷淋时的气相压损为仅底层喷淋的2倍。吸收塔内,喷淋层所在区段的湍动能最高;喷淋层数越多,高湍动能区域的范围和数值均增大。多层喷淋时,在第2层喷淋位置的截面平均湍动能最高,烟气继续往上流动,湍动能逐渐减小。不管喷淋层组合方式如何,烟气降温速率和水蒸气浓度增加速率的极大值所在位置都位于底层喷淋以下、近烟气入口上缘处。模拟发现,塔内潜热换热和显热换热各占总换热量的87%和13%。The impact of different spraying layers scheme on gas-liquid two phases flow,heat and mass transfer in the large scale desulphurization tower with four spraying layers was investigated by numerical simulation.The Euler-Lagrange approach was adopted for the numerical calculation and the inter-exchange of momentum,mass and energy between the two phases was fully considered;the effect of instantaneous turbulent velocity fluctuations on the particle trajectories was also taken into account.Dependability of the simulation was validated via actual on-site data.The results show that large vortex region on the upper left of the tower inlet occurs when only the bottom spraying layer opens.But when only the top spraying layer or multiple layers operate,the gas-liquid contact is much greater and the above-mentioned non-uniformity in the flue gas distribution will not appear.The more spraying layers operate,the higher the pressure loss in the tower is.When only the top spraying layer operates,the pressure loss in the spraying zone is twice as much as that when only the bottom spraying layer is employed.In the absorption tower,the highest turbulence kinetic energy region is located in the spraying zone.With more spraying layers are put into operation,the region of high turbulence kinetic energy is enlarged and its value increases also.When multiple layers operate,area-weighted mean turbulence kinetic energy on the2nd spraying layer reaches to maximum in the whole spaying zone,while the value on the top spraying layer is even lower than that on the3rd layer.With regard to the heat and mass transfer in the desulphurization tower,no matter what kind of spraying layer scheme is adopted,the location corresponding to the biggest flue gas quenching rate and the location corresponding to the biggest water vapor generating rate are found coincident,which are located just above the upper plane of the flue gas inlet and beneath the bottom spraying layer.The simulation result also shows that the latent heat transferred through droplet ev

关 键 词：湿法脱硫 喷淋层组合 气液两相流 热湿交换 数值模拟 

分 类 号：TK16[动力工程及工程热物理—热能工程]