喷淋方向对船舶Ⅰ型脱硫塔内部流场的影响
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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。
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.
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.
引文
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9 Chen Z,Wang H,Zhou J,et al. Experimental and numerical study on effects of deflectors on flow field distribution and desulfurization efficiency in spray towers[J]. Fuel Processing Technology,2017,162:1-12
10 盖国胜.船舶动力装置海水脱硫系统仿真及试验研究[D].哈尔滨:哈尔滨工程大学,2012Gai Guosheng. Numerical simulation and experiment research about seawater desulphurization of ship[D]. Harbin:Harbin Engineering University,2012
11 李国诚,郑高.船用脱硫塔塔内气流场的数值模拟研究[J].船舶标准化工程师,2015(4):75-80Li Guocheng,Zheng Gao. Numerical simulation research of airflow in marine desulfurization tower[J]. Ship Standardization Engineer,2015(4):75-80
12 刘全,孙美君,张曼霞,等.船舶废气脱硫塔内流场设计研究[J].计算机仿真,2016,33(5):244-248Liu Quan,Sun Meijun,Zhang Manxia,et al. Research on flow field design in ship exhaust gas desulfurization tower[J]. Computer Simulation,2016,33(5):244-248
13 Edwards D P,Krishnamurthy K R,Potthoff R W. Development of an improved method to quantify maldistribution and its effect on structured packing column performance[J]. Chemical Engineering Research&Design,1999,77(7):656-662
2 Mahmoud Ibrahim A E D M. NOx and SOx emissions and climate changes[J]. World Applied Sciences Journal,2014,31(8):1422-1426
3 朱益民,唐晓佳,张仁平,等.船舶硫氧化物排放控制研究进展[J].环境工程,2014,32(8):68-71Zhu Yimin,Tang Xiaojia,Zhang Renpin,et al. A review on marine exhaust SOx control technology[J]. Environmental Engineering,2014,32(8):68-71
4 周松,李琤,沈飞翔.船舶废气洗涤脱硫技术现状及发展趋势[J].柴油机,2014,36(5):1-6Zhou Song,Li Cheng,Shen Feixiang. The status of marine engine exhaust gas scrubbing and desulfurizing technology and its development trend[J]. Diesel Engine,2014,36(5):1-6
5 Wang S J,Zhu P,Zhang G,et al. Numerical simulation research of flow field in ammonia-based wet flue gas desulfurization tower[J].Journal of the Energy Institute,2015,88(3):284-291
6 Zhang Qi,Wang Shijie,Zhu Ping,et al. Full-scale simulation of flow field in ammonia-based wet flue gas desulfurization double tower[J]. Journal of the Energy Institute,2018,91(4):619-629
7 林瑜,陈德珍,尹丽洁.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[J].中南大学学报(自然科学版),2017,48(10):2572-2582Lin Yu,Chen Dezhen,Yin Lijie. Numerical simulation of impact of spraying layers scheme on gas-liquid two phases flow,heat and mass transfer in large scale desulphurization absorption tower[J]. Journal of Central South University(Science and Technology),2017,48(10):2572-2582
8 洪文鹏,刘广林,裴彩锋,等.入口角度对氨法烟气脱硫塔内气液流场影响的数值模拟[J].动力工程学报,2012,32(4):326-331Hong Wenpeng,Liu Guanglin,Pei Caifeng,et al. Influence of entrance angle on gas-liquid flow flied in ammonia flue gas desulphurization tower[J]. Journal of Chinese Society of Power Engineering,2012,32(4):326-331
9 Chen Z,Wang H,Zhou J,et al. Experimental and numerical study on effects of deflectors on flow field distribution and desulfurization efficiency in spray towers[J]. Fuel Processing Technology,2017,162:1-12
10 盖国胜.船舶动力装置海水脱硫系统仿真及试验研究[D].哈尔滨:哈尔滨工程大学,2012Gai Guosheng. Numerical simulation and experiment research about seawater desulphurization of ship[D]. Harbin:Harbin Engineering University,2012
11 李国诚,郑高.船用脱硫塔塔内气流场的数值模拟研究[J].船舶标准化工程师,2015(4):75-80Li Guocheng,Zheng Gao. Numerical simulation research of airflow in marine desulfurization tower[J]. Ship Standardization Engineer,2015(4):75-80
12 刘全,孙美君,张曼霞,等.船舶废气脱硫塔内流场设计研究[J].计算机仿真,2016,33(5):244-248Liu Quan,Sun Meijun,Zhang Manxia,et al. Research on flow field design in ship exhaust gas desulfurization tower[J]. Computer Simulation,2016,33(5):244-248
13 Edwards D P,Krishnamurthy K R,Potthoff R W. Development of an improved method to quantify maldistribution and its effect on structured packing column performance[J]. Chemical Engineering Research&Design,1999,77(7):656-662