【摘要】 随着船舶尾气排放法规的严苛,如何提高船舶脱硫塔脱硫效率,以及减小压降成为生产设计中的重要因素。以Ⅰ型脱硫塔为研究对象,通过改变喷嘴的喷射方向对内部流场特性进行了优化。首先利用欧拉-拉格朗日方程建立了气液两相流动模型,其中烟气为连续相,喷淋液滴为离散相。采用多孔介质模型替代除雾器以计算其产生的压降,利用ANSYS Fluent分别仿真三个不同喷射方向(A30、A90、A150)的脱硫塔内部流场。将A30的仿真结果与工厂实验进行对比,结果表明仿真得到的脱硫塔烟气出口温度及入口至除雾器下方的压降值与实验数据基本一致,证明了仿真的准确性。通过对三种喷射条件下的内部流场、温度及压力特性的对比研究,结果表明:三种喷射方向对脱硫塔压降影响不大,对烟气的降温效果均不佳,其中A90所产生的降温效果和压降与A30几乎一样,A150喷射产生的压降相对较大及烟气降温效果相对较好;三种喷射方向均易造成烟气产生逃逸,其中A90逃逸现象最严重; A30的烟气截面速度标准偏差值相对较低,更有助于气液两相接触。综合考虑采用A30喷射方式更有利于脱硫。更多还原

【Abstract】 With the strict regulations on ship exhaust emissions,how to improve the desulfurization efficiency of desulfurization tower and reduce the pressure drop become an important factor in production design are preseuted.Based on the Ⅰ-type desulfurization tower,the internal flow field characteristics are optimized by optimizing the injection direction of the nozzle. Firstly,a gas-liquid two-phase flow model is established by using the Euler-Lagrange equation,in which the flue gas is a continuous phase and the spray droplets are discrete phases. The porous media model was used to replace the demister to calculate the pressure drop generated. The internal gas-liquid flow characteristics of three different injection directions( A30,A90,A150) desulfurization towers were simulated by ANSYS Fluent. Comparing the simulation results of the injection direction A30 with the experimental data,the results show that the simulated desulfurization tower outlet temperature and the pressure drop of the inlet to the demister,which is basically consistent with the experimental data,which proves the accuracy of the simulation. A comparative study of internal flow field,temperature and pressure characteristics under three injection conditions is presented. The results show that the three injection directions have little effect on the pressure drop of the desulfurization tower,and the cooling effect on the flue gas is not good. Among them,the cooling effect and pressure drop produced by A90 are almost the same as those of A30. The pressure drop generated by A150 injection is relatively large and the effect of flue gas cooling is relatively good. The three spray directions are easy to cause flue gas to escape and the A90 escape phenomenon is the most serious. The A30 has a relatively low standard deviation of the cross-section velocity of the flue gas,which is more conducive to the gas-liquid two-phase contact. Comprehensive consideration of the A30 injection method is more conducive to desulfurization.更多还原