喷淋层运行方式对脱硫塔内气液两相运动规律和蒸发冷却过程影响的数值模拟
|
摘要
通过计算流体力学方法对大型脱硫塔内不同喷淋层的运行方式进行数值仿真,并和工程现场数据作对比.模拟采用欧拉-拉格朗日方法,并考虑了气液两相间的各种耦合作用,以及气相湍流速度脉动的随机特征对颗粒相的影响.主要结论如下:①各喷淋工况下,在烟气入口高度范围内,截面平均气流总速度和水平向(水平烟气方向)分速度均达到峰值后快速衰减,其中后者至底层喷淋处趋于零;截面平均垂直速度分量沿塔高方向的变化曲线几乎完全重合,且在整个烟气入口高度范围内单调线性增加;②各喷淋方案中,仅底层喷淋时塔内的气相温度场和水蒸气浓度场最不均匀,烟气出口截面的平均温度明显高于其他工况,出口截面的平均湿度也未达到饱和;而仅顶层喷淋时,上述不均匀性明显减小;③各喷淋方案(除仅底层喷淋外),截面平均气相温、湿度沿塔高方向变化曲线的极值都出现在烟气入口高度的下部1/4处;随着喷淋层数增多,温度曲线的最大值降低,湿度曲线的最低值则升高;④仅底层喷淋时的蒸发水量为4层喷淋全部开启时的4/5;而仅顶层喷淋时的蒸发水量和开启更多喷淋层时已没有明显差别.各喷淋方案中,仅顶层喷淋时的蒸发比率最高.
The operation modes of spraying layers in the large scale desulphurization tower with four spraying layers were investigated by computational fluid dynamics numerical simulation. The Euler-Lagrange approach was adopted and the inter-exchanges of momentum,mass and energy between the gas and liquid phase were fully studied; the effect of instantaneous turbulent velocity fluctuations on the particle trajectories was also taken into account through the use of stochastic methods. The simulation results were also validated via actual on-site data. The main results are as follow:(1) for all spraying modes,the area-weighted mean total velocity and its horizontal component of the gas phase on the horizontal cross-sections reach to their peak values inside the height of the flue gas inlet and then decline quickly,the horizontal component almost decreases to 0 when the flue gas comes to the bottom spraying layer. Meanwhile,the curves of area-weighted mean vertical velocity components of all spraying modes almost overlap completely along the absorption tower,and inside the height of the flue gas inlet,they show perfect mono-tonous linear increase.(2) Among all spraying modes,the most non-uniformity in the temperature field and water vapor field of the flue gas occurs when only bottom spraying layer operating. In addition,in such spraying mode,the area-weighted mean temperature on the flue gas outlet is much higher than the other spraying modes,and the area-weighted mean humidity on the flue gas outlet is not saturated. Whereas,the above-mentioned non-uniformity is alleviated obviously when only top spraying layer operating.(3) For all spraying modes except only bottom spray-ing layer operating,the curve extremums of area-weighted mean temperature and humidity of the gas phase on the horizontal cross-sections along the absorption tower are all located within the lower quarter height of the flue gas inlet. With the increase of spraying layers,the maximum values of the above-mentioned temperature curves decrease,while the minimum values of the humidity curves increase.(4) When only bottom spraying layer operates,the evaporation water quantity accounts for four fifths the value when all the four spraying layers operating. There is no significant difference in evaporation water quantity between only top spraying layer mode and other multiple layers modes. Among all the spraying modes,the highest evaporation ratio is found when only top spraying layer adopted.
The operation modes of spraying layers in the large scale desulphurization tower with four spraying layers were investigated by computational fluid dynamics numerical simulation. The Euler-Lagrange approach was adopted and the inter-exchanges of momentum,mass and energy between the gas and liquid phase were fully studied; the effect of instantaneous turbulent velocity fluctuations on the particle trajectories was also taken into account through the use of stochastic methods. The simulation results were also validated via actual on-site data. The main results are as follow:(1) for all spraying modes,the area-weighted mean total velocity and its horizontal component of the gas phase on the horizontal cross-sections reach to their peak values inside the height of the flue gas inlet and then decline quickly,the horizontal component almost decreases to 0 when the flue gas comes to the bottom spraying layer. Meanwhile,the curves of area-weighted mean vertical velocity components of all spraying modes almost overlap completely along the absorption tower,and inside the height of the flue gas inlet,they show perfect mono-tonous linear increase.(2) Among all spraying modes,the most non-uniformity in the temperature field and water vapor field of the flue gas occurs when only bottom spraying layer operating. In addition,in such spraying mode,the area-weighted mean temperature on the flue gas outlet is much higher than the other spraying modes,and the area-weighted mean humidity on the flue gas outlet is not saturated. Whereas,the above-mentioned non-uniformity is alleviated obviously when only top spraying layer operating.(3) For all spraying modes except only bottom spray-ing layer operating,the curve extremums of area-weighted mean temperature and humidity of the gas phase on the horizontal cross-sections along the absorption tower are all located within the lower quarter height of the flue gas inlet. With the increase of spraying layers,the maximum values of the above-mentioned temperature curves decrease,while the minimum values of the humidity curves increase.(4) When only bottom spraying layer operates,the evaporation water quantity accounts for four fifths the value when all the four spraying layers operating. There is no significant difference in evaporation water quantity between only top spraying layer mode and other multiple layers modes. Among all the spraying modes,the highest evaporation ratio is found when only top spraying layer adopted.
引文
[1] 田海军,宋存义,赵荣志,等.密相塔烟气入口角度的数值模拟和优化设计 [J].中国冶金,2016,26(5):25- 31,36.TIAN Hai-jun,SONG Cun-yi,ZHAO Rong-zhi,et al.Numerical simulation and optimization on inlet angle of flue gas for dense phase tower [J].China Metallurgy,2016,26(5):25- 31,36.
[2] 周赞庆,孙勤贺.燃煤锅炉导流板型脱硫烟塔的烟气流场优化设计 [J].电力科技与环保,2015,31(5):32- 34.ZHOU Zan-qing,SUN Qin-he.Design on optimization of gas flow field in desulfurization absorber with deflectors [J].Electric Power and Environmental Protection,2015,31(5):32- 34.
[3] 唐强,侯世锋,张晓琴.旁通式烟气循环流化床脱硫特性的数值模拟 [J].环境工程学报,2012,6(7):2401- 2405.TANG Qiang,HOU Shifeng,ZHANG Xiaoqin.Numerical simulation of desulfurization characteristics in flue gas CFB with bypass [J].Chinese Journal of Environmental Engineering,2012,6(7):2401- 2405.
[4] 龚艳艳,王乃继,肖翠微,等.灰钙循环烟气脱硫反应器空床阻力的数值模拟 [J].工业锅炉,2015,149(1):15- 19.GONG Yan-yan,WANG Nai-ji,XIAO Cui-wei,et al.Numerical simulation of empty bed resistance in the ash & calcium circulating flue gas desulfurization reactor [J].Industrial Boiler,2015,149(1):15- 19.
[5] WEISS C,WIELTSCH U.Laser optical flow measurements and computational fluid dynamic calculation of spray tower hydrodynamics [J].Chemical Engineering Research and Design,2005,83(A5):492- 507.
[6] 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- 248,267.LIU Quan,SUN Mei-jun,ZHANG Man-xia,et al.Research on flow field design in ship exhaust gas desulfurization tower [J].Computer Simulation,2016,33(5):244- 248,267.
[7] 林永明,高翔,施平平,等.大型湿法烟气脱硫喷淋塔内阻力特性数值模拟[J].中国电机工程学报,2008,28(5):28- 33.LIN Yong-ming,GAO Xiang,SHI Ping-ping,et al.Numeri-cal simulation on resistance characteristic of large scale wet flue gas desulphurization spraying scrubber [J].Proceedings of the Chinese Society for Electrical Engineering,2008,28(5):28- 33.
[8] HOFELSAUER J,NOTTER W,MAROCCO L,et al.Improvement of SO2 removal with application of wall rings and advanced CFD modelling—the case of FGD unit Megalopolis [J].VGB Power Technology,2008,3(1):85- 97.
[9] 曾劲松,陈克复,李军,等.基于CFD的高浓漂白塔塔底S型卸料器的流场研究 [J].华南理工大学学报(自然科学版),2011,39(1):24- 29.ZENG Jin-song,CHEN Ke-fu,LI Jun,et al.CFD-based investigation into flow field of S- type discharger at the bottom of high-consistency pulp-bleaching tower [J].Journal of South China University of Technology(Natural Science Edition),2011,39(1):24- 29.
[10] MAROCCO Luca.Modeling of the fluid dynamics and SO2 absorption in a gas-liquid reactor [J].Chemical Engineering Journal,2010,162(1):217- 226.
[11] KALLINIKOS L E,FARSARI E I,SPARTINOS D N,et al.Simulation of the operation of an industrial wet flue gas desulfurization system [J].Fuel Processing Techno-logy,2010,91(12):1794- 1802.
[12] ZHONG Yi,GAO Xiang,HUO Wang,et al.A model for performance optimization of wet flue gas desulfurization systems of power plants [J].Fuel Processing Technology,2008,89(11):1025- 1032.
[13] 陶敏,金保升,仲兆平,等.循环流化床烟气脱硫多层喷水数学模型 [J].东南大学学报(自然科学版),2010,40(1):144- 148.TAO Min,JIN Baosheng,ZHONG Zhaoping,et al.Mathe-matical model for multi-level humidifying of the circula-ting fluidized bed-flue gas desulfurization system [J].Journal of Southeast University(Natural Science Edition),2010,40(1):144- 148.
[14] KONG Dejuan,ZHANG Ya-fei,LI Na,et al.Experimental investigation on gas-liquid flow,heat and mass transfer characteristics in a dual-contact-flow absorption tower [J].Chemical Engineering Research and Design,2014,92(1):13- 24.
[15] 戚美,陈朋,陈庆光,等.湍流器对湿法脱硫塔内热态流场影响的数值模拟 [J].环境工程学报,2018,12(7):2018- 2028.QI Mei,CHEN Peng,CHEN Qingguang,et al.Numerical simulation of effect of turbulator on thermal flow field in wet flue gas [J].Chinese Journal of Environmental Engineering,2018,12(7):2018- 2028.
[16] 史文峥,杨萌萌,张绪辉,等.燃煤电厂超低排放技术路线与协同脱除 [J].中国电机工程学报,2016,36(16):4308- 4318.SHI Wenzheng,YANG Mengmeng,ZHANG Xuhui,et al.Ultra-low emission technical route of coal-fired power plants and the cooperative removal [J].Proceedings of the CSEE,2016,36(16):4308- 4318.
[17] MORSI S A,ALEXANDER A J.An investigation of particle trajectories in two-phase flow systems [J].Journal of Fluid Mechanics,1972,55(2):193- 208.
[18] RANZ W E,MARSHALL W R.Evaporation from drops.parts I and II [J].Chemical Engineering Progress,1952,48(3):141- 146,173- 180.
[19] FULLER E N,SCHETTLER P D,GIDDINGS J C.A new method for prediction of binary gas-phase diffusion coefficients [J].Industrial and Engineering Chemistry,1966,58(5):18- 27.
[20] 魏书洲,张国新,郝剑,等.脱硫吸收塔流场优化及研究 [J].华北电力技术,2016,45(2):65- 70.WEI Shuzhou,ZHANG Guoxin,HAO Jian,et al.Optimization and research of desulfurization absorber flow field [J].North China Electric Power,2016,45(2):65- 70.
[2] 周赞庆,孙勤贺.燃煤锅炉导流板型脱硫烟塔的烟气流场优化设计 [J].电力科技与环保,2015,31(5):32- 34.ZHOU Zan-qing,SUN Qin-he.Design on optimization of gas flow field in desulfurization absorber with deflectors [J].Electric Power and Environmental Protection,2015,31(5):32- 34.
[3] 唐强,侯世锋,张晓琴.旁通式烟气循环流化床脱硫特性的数值模拟 [J].环境工程学报,2012,6(7):2401- 2405.TANG Qiang,HOU Shifeng,ZHANG Xiaoqin.Numerical simulation of desulfurization characteristics in flue gas CFB with bypass [J].Chinese Journal of Environmental Engineering,2012,6(7):2401- 2405.
[4] 龚艳艳,王乃继,肖翠微,等.灰钙循环烟气脱硫反应器空床阻力的数值模拟 [J].工业锅炉,2015,149(1):15- 19.GONG Yan-yan,WANG Nai-ji,XIAO Cui-wei,et al.Numerical simulation of empty bed resistance in the ash & calcium circulating flue gas desulfurization reactor [J].Industrial Boiler,2015,149(1):15- 19.
[5] WEISS C,WIELTSCH U.Laser optical flow measurements and computational fluid dynamic calculation of spray tower hydrodynamics [J].Chemical Engineering Research and Design,2005,83(A5):492- 507.
[6] 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- 248,267.LIU Quan,SUN Mei-jun,ZHANG Man-xia,et al.Research on flow field design in ship exhaust gas desulfurization tower [J].Computer Simulation,2016,33(5):244- 248,267.
[7] 林永明,高翔,施平平,等.大型湿法烟气脱硫喷淋塔内阻力特性数值模拟[J].中国电机工程学报,2008,28(5):28- 33.LIN Yong-ming,GAO Xiang,SHI Ping-ping,et al.Numeri-cal simulation on resistance characteristic of large scale wet flue gas desulphurization spraying scrubber [J].Proceedings of the Chinese Society for Electrical Engineering,2008,28(5):28- 33.
[8] HOFELSAUER J,NOTTER W,MAROCCO L,et al.Improvement of SO2 removal with application of wall rings and advanced CFD modelling—the case of FGD unit Megalopolis [J].VGB Power Technology,2008,3(1):85- 97.
[9] 曾劲松,陈克复,李军,等.基于CFD的高浓漂白塔塔底S型卸料器的流场研究 [J].华南理工大学学报(自然科学版),2011,39(1):24- 29.ZENG Jin-song,CHEN Ke-fu,LI Jun,et al.CFD-based investigation into flow field of S- type discharger at the bottom of high-consistency pulp-bleaching tower [J].Journal of South China University of Technology(Natural Science Edition),2011,39(1):24- 29.
[10] MAROCCO Luca.Modeling of the fluid dynamics and SO2 absorption in a gas-liquid reactor [J].Chemical Engineering Journal,2010,162(1):217- 226.
[11] KALLINIKOS L E,FARSARI E I,SPARTINOS D N,et al.Simulation of the operation of an industrial wet flue gas desulfurization system [J].Fuel Processing Techno-logy,2010,91(12):1794- 1802.
[12] ZHONG Yi,GAO Xiang,HUO Wang,et al.A model for performance optimization of wet flue gas desulfurization systems of power plants [J].Fuel Processing Technology,2008,89(11):1025- 1032.
[13] 陶敏,金保升,仲兆平,等.循环流化床烟气脱硫多层喷水数学模型 [J].东南大学学报(自然科学版),2010,40(1):144- 148.TAO Min,JIN Baosheng,ZHONG Zhaoping,et al.Mathe-matical model for multi-level humidifying of the circula-ting fluidized bed-flue gas desulfurization system [J].Journal of Southeast University(Natural Science Edition),2010,40(1):144- 148.
[14] KONG Dejuan,ZHANG Ya-fei,LI Na,et al.Experimental investigation on gas-liquid flow,heat and mass transfer characteristics in a dual-contact-flow absorption tower [J].Chemical Engineering Research and Design,2014,92(1):13- 24.
[15] 戚美,陈朋,陈庆光,等.湍流器对湿法脱硫塔内热态流场影响的数值模拟 [J].环境工程学报,2018,12(7):2018- 2028.QI Mei,CHEN Peng,CHEN Qingguang,et al.Numerical simulation of effect of turbulator on thermal flow field in wet flue gas [J].Chinese Journal of Environmental Engineering,2018,12(7):2018- 2028.
[16] 史文峥,杨萌萌,张绪辉,等.燃煤电厂超低排放技术路线与协同脱除 [J].中国电机工程学报,2016,36(16):4308- 4318.SHI Wenzheng,YANG Mengmeng,ZHANG Xuhui,et al.Ultra-low emission technical route of coal-fired power plants and the cooperative removal [J].Proceedings of the CSEE,2016,36(16):4308- 4318.
[17] MORSI S A,ALEXANDER A J.An investigation of particle trajectories in two-phase flow systems [J].Journal of Fluid Mechanics,1972,55(2):193- 208.
[18] RANZ W E,MARSHALL W R.Evaporation from drops.parts I and II [J].Chemical Engineering Progress,1952,48(3):141- 146,173- 180.
[19] FULLER E N,SCHETTLER P D,GIDDINGS J C.A new method for prediction of binary gas-phase diffusion coefficients [J].Industrial and Engineering Chemistry,1966,58(5):18- 27.
[20] 魏书洲,张国新,郝剑,等.脱硫吸收塔流场优化及研究 [J].华北电力技术,2016,45(2):65- 70.WEI Shuzhou,ZHANG Guoxin,HAO Jian,et al.Optimization and research of desulfurization absorber flow field [J].North China Electric Power,2016,45(2):65- 70.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |