蒸汽相变促进烟气中细颗粒生长的数值模拟
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摘要
利用气相与颗粒相耦合模拟计算烟气中细颗粒的生长情况,其中气相采用的是湍流模型中的k-ε模型,颗粒相采用的是颗粒群平衡模型(Population Balance Model, PBM),在流动过程中通过固液两相间的相互作用将两相耦合。分析了相同初始过饱和度下不同温度的含尘烟气对异质成核过程中管内过饱和度及粒径分布的影响;并研究不同初始饱和度、颗粒在生长管内的停留时间以及生长管壁温对管内细颗粒异质成核的影响。结果表明:温度升高会导致管内过饱和度降低,异质成核的速率下降;初始饱和度越大,管内过饱和环境充分,有利于细颗粒生长;细颗粒在生长管内停留的时间越长,异质成核作用越充分,有利于细颗粒的生长;生长管内的壁温低于烟气温度时,管内过饱和度越大,促进细颗粒的生长。
The growth of fine particles size in flue gas was investigated by coupling simulation of gas-phase and particle phase. In the simulation process, gas-phase was solved by using k-ε model of the turbulent model, and particle phase was solved by using population balance model, and finally the couple of gas-particle phase was linked by interaction of the phases. It was analyzed that the distribution of supersaturation and particle size in the same initial supersaturation and different temperature of the flue gas, which is in the progress of the heterogeneous nucleation. It was also analyzed the effect of the fine particles heterogeneous nucleation in different initial supersaturation, residence time of the particles in the growth tube, and the wall temperature of the growth tube. The results show that the increase of temperature of flue gas would lead to the decrease of supersaturation in the growth tube, and cause the decrease of heterogeneous nucleation rate;Higher initial supersaturation and better environment of the supersaturation in the tube are good for the growth of fine particles. The longer time the fine particles stay in the tube, the better reaction of the heterogeneous nucleation will be, which is good for the growth of fine particles. When the wall temperature is lower than the gas temperature, the supersaturation of the growth tube would be larger, and it would promote the growth of fine particles.
The growth of fine particles size in flue gas was investigated by coupling simulation of gas-phase and particle phase. In the simulation process, gas-phase was solved by using k-ε model of the turbulent model, and particle phase was solved by using population balance model, and finally the couple of gas-particle phase was linked by interaction of the phases. It was analyzed that the distribution of supersaturation and particle size in the same initial supersaturation and different temperature of the flue gas, which is in the progress of the heterogeneous nucleation. It was also analyzed the effect of the fine particles heterogeneous nucleation in different initial supersaturation, residence time of the particles in the growth tube, and the wall temperature of the growth tube. The results show that the increase of temperature of flue gas would lead to the decrease of supersaturation in the growth tube, and cause the decrease of heterogeneous nucleation rate;Higher initial supersaturation and better environment of the supersaturation in the tube are good for the growth of fine particles. The longer time the fine particles stay in the tube, the better reaction of the heterogeneous nucleation will be, which is good for the growth of fine particles. When the wall temperature is lower than the gas temperature, the supersaturation of the growth tube would be larger, and it would promote the growth of fine particles.
引文
[1] WAGNER P E. Aerosol growth by condensation[J]. Topics in Current Physics,1982,16(5):129-178.
[2] VOLMER M.über keimbildung und keimwirkung als spezialf?lle der heterogenen katalyse[J]. Zeitschrift Für Elektrochemie Berichte Der Bunsengesellschaft Für Physikalische Chemie,2015,35(9):555-561.
[3] TWOMEY S. Experimental test of the volmer theory of heterogeneous nucleation[J]. Journal of Chemical Physics,1959,30(4):941-943.
[4] FLETCHER N H. Size effect in heterogeneous nucleation[J]. Journal of Chemical Physics,1958,29(3):572-576.
[5] YU F,QIN F H,LUO X S,et al. Heterogeneous condensation on insoluble spherical particles:Modeling and parametric study[J]. Chemical Engineering Science,2013,102(15):387-396.
[6] CHEN C C,GUO M S,TSAI Y J,et al. Heterogeneous nucleation of water vapor on submicrometer particles of SiC,SiO2,and naphthalene[J]. Journal of Colloid and Interface Science,1998,198(2):354-367.
[7] HERING S V,STOLZENBURG M R. A method for particle size amplification by water condensation in a laminar,thermally diffusive flow[J]. Aerosol Science and Technology,2005,39(5):428-436.
[8] YANG L,BAO J,YAN J,et al. Removal of fine particles in wet flue gas desulfurization system by heterogeneous condensation[J]. Chemical Engineering Journal,2010,156(1):25-32.
[9] WU H,PAN D P,XIONG G L,et al. The abatement of fine particles from desulfurized flue gas by heterogeneous vapor condensation coupling two impinging streams[J]. Chemical Engineering&Processing Process Intensification,2016,108:174-180.
[10]熊桂龙,杨林军,颜金培,等.对喷流协同蒸汽相变对燃煤细颗粒脱除性能的影响[J].中国电机工程学报,2011,31(32):39-45.
[11]孙露娟,杨林军,张霞,等.洗涤塔脱除燃烧源超细颗粒的实验研究[J].化工学报,2008,59(6):1508-1514.
[12]熊桂龙.水汽相变耦合撞击流促进细颗粒物脱除的研究[D].南京:东南大学,2012.
[13]姜业正,吴昊,雒飞,等.添加湿空气对湿法脱硫净烟气中细颗粒物脱除性能[J].东南大学学报(自然科学版),2016,46(1):81-86.
[14] XU J C,YU Y,ZHANG J,et al. Heterogeneous condensation of water vapor on particles at high concentration[J]. Powder Technology,2017,305:71-77.
[2] VOLMER M.über keimbildung und keimwirkung als spezialf?lle der heterogenen katalyse[J]. Zeitschrift Für Elektrochemie Berichte Der Bunsengesellschaft Für Physikalische Chemie,2015,35(9):555-561.
[3] TWOMEY S. Experimental test of the volmer theory of heterogeneous nucleation[J]. Journal of Chemical Physics,1959,30(4):941-943.
[4] FLETCHER N H. Size effect in heterogeneous nucleation[J]. Journal of Chemical Physics,1958,29(3):572-576.
[5] YU F,QIN F H,LUO X S,et al. Heterogeneous condensation on insoluble spherical particles:Modeling and parametric study[J]. Chemical Engineering Science,2013,102(15):387-396.
[6] CHEN C C,GUO M S,TSAI Y J,et al. Heterogeneous nucleation of water vapor on submicrometer particles of SiC,SiO2,and naphthalene[J]. Journal of Colloid and Interface Science,1998,198(2):354-367.
[7] HERING S V,STOLZENBURG M R. A method for particle size amplification by water condensation in a laminar,thermally diffusive flow[J]. Aerosol Science and Technology,2005,39(5):428-436.
[8] YANG L,BAO J,YAN J,et al. Removal of fine particles in wet flue gas desulfurization system by heterogeneous condensation[J]. Chemical Engineering Journal,2010,156(1):25-32.
[9] WU H,PAN D P,XIONG G L,et al. The abatement of fine particles from desulfurized flue gas by heterogeneous vapor condensation coupling two impinging streams[J]. Chemical Engineering&Processing Process Intensification,2016,108:174-180.
[10]熊桂龙,杨林军,颜金培,等.对喷流协同蒸汽相变对燃煤细颗粒脱除性能的影响[J].中国电机工程学报,2011,31(32):39-45.
[11]孙露娟,杨林军,张霞,等.洗涤塔脱除燃烧源超细颗粒的实验研究[J].化工学报,2008,59(6):1508-1514.
[12]熊桂龙.水汽相变耦合撞击流促进细颗粒物脱除的研究[D].南京:东南大学,2012.
[13]姜业正,吴昊,雒飞,等.添加湿空气对湿法脱硫净烟气中细颗粒物脱除性能[J].东南大学学报(自然科学版),2016,46(1):81-86.
[14] XU J C,YU Y,ZHANG J,et al. Heterogeneous condensation of water vapor on particles at high concentration[J]. Powder Technology,2017,305:71-77.