Operating conditions strongly affect the yield and quality of polysilicon in a polysilicon fluidized bed.In this study,a new model of polysilicon fluidized bed was established using the Euler-Euler model coupled with ...Operating conditions strongly affect the yield and quality of polysilicon in a polysilicon fluidized bed.In this study,a new model of polysilicon fluidized bed was established using the Euler-Euler model coupled with population balance model(PBM),which was combined with fluid flow,heat,and mass transfer models,while considering the scavenging effect of silicon fines.The effects of different operating conditions on the deposition and formation rates of silicon fines were investigated.Results show that the model can correctly describe the particle growth process in the fluidized bed of polysilicon.The silicon fines and the interphase velocity difference show"N"-and"M"-shaped distributions along the axial direction,respectively.The particle temperature and concentration near the wall are higher than those in the central region.The decomposition of silane in the bottom region of the bed is dominated by het-erogeneous deposition.The scavenging of silicon fines occurs in the dilute-phase region.The effects of operating conditions,i.e.inlet gas temperature,silane composition,and gas velocity,on the reactor performance were also explored comprehensively.Increasing the inlet gas composition and velocity enhances the formation rates of solid silicon and fines.Increasing the inlet gas temperature promotes the growth of solid silicon and inhibits the formation of silicon fines.High fluidization ratio,low inlet silane concentration,and high inlet gas temperature enhance the selectivity of silicon growth.展开更多
The seriousness of losses caused by disaster dependent on the hazard degree of environment,vulnerability of hazard-affected bodies,and emergency response capacity of the region is studied in this article.The study on ...The seriousness of losses caused by disaster dependent on the hazard degree of environment,vulnerability of hazard-affected bodies,and emergency response capacity of the region is studied in this article.The study on hazard-affected bodies is of importance to disaster risk management,regional hazard prevention,reduction,and investment in disaster insurance.With summarizing of various assessment methods of vulnerability of hazard-affected bodies,this paper presents a refined Spatial Quantification Model of regional vulnerability which combines refined spatial geographic data and land-use type data.A quantitative study on regional vulnerability was carried out by defining fine spatial grid as the basic evaluation unit based on GIS.展开更多
基金support by the Science and Technology Planning Project of the Science and Technology Department of Yunnan Province (grant No.202002AB080002 and 202202AB080014).
文摘Operating conditions strongly affect the yield and quality of polysilicon in a polysilicon fluidized bed.In this study,a new model of polysilicon fluidized bed was established using the Euler-Euler model coupled with population balance model(PBM),which was combined with fluid flow,heat,and mass transfer models,while considering the scavenging effect of silicon fines.The effects of different operating conditions on the deposition and formation rates of silicon fines were investigated.Results show that the model can correctly describe the particle growth process in the fluidized bed of polysilicon.The silicon fines and the interphase velocity difference show"N"-and"M"-shaped distributions along the axial direction,respectively.The particle temperature and concentration near the wall are higher than those in the central region.The decomposition of silane in the bottom region of the bed is dominated by het-erogeneous deposition.The scavenging of silicon fines occurs in the dilute-phase region.The effects of operating conditions,i.e.inlet gas temperature,silane composition,and gas velocity,on the reactor performance were also explored comprehensively.Increasing the inlet gas composition and velocity enhances the formation rates of solid silicon and fines.Increasing the inlet gas temperature promotes the growth of solid silicon and inhibits the formation of silicon fines.High fluidization ratio,low inlet silane concentration,and high inlet gas temperature enhance the selectivity of silicon growth.
基金funded by the Science and Technology project of the Meteorological Bureau of Zhejiang Province in 2010(No.2010ZD05)Science and Technology projects in Zhejiang Province(No.2007C33062).
文摘The seriousness of losses caused by disaster dependent on the hazard degree of environment,vulnerability of hazard-affected bodies,and emergency response capacity of the region is studied in this article.The study on hazard-affected bodies is of importance to disaster risk management,regional hazard prevention,reduction,and investment in disaster insurance.With summarizing of various assessment methods of vulnerability of hazard-affected bodies,this paper presents a refined Spatial Quantification Model of regional vulnerability which combines refined spatial geographic data and land-use type data.A quantitative study on regional vulnerability was carried out by defining fine spatial grid as the basic evaluation unit based on GIS.
