关键词: 生物质飞灰, 旋风除尘器, 高温流场, 颗粒浓度分布, 数值模拟

Abstract: In view of that the concentrations of fly ash particles in cyclone separators of biomass gasification station are very high,it is much difficult to measure the biomass ash concentration,and a cyclone separator's separation efficiency is closely related to the turbulent flow field with high temperature,a simulation model was established by computational fluid dynamics (CFD) software based on characters of cyclone separator in gasification station,for obtaining the concentration distribution of ash particles and studying the relationship between the separation efficiency,biomass gas temperature and gas velocity.The biomass gas at high temperature released from gasifier was taken as the object of this study.The coupling migration of both air and fly ash inside the cyclone separator at high temperature was studied in numerical simulation,using a gas-particle coupling mathematic model.The results show that the phenomenon of upper dust ring exists in the annular space,that the separation ability of cylinder space is much better than that of cone space,that the ash concentration distribution curve in cone space and that in cylinder space are a bathtub curve,that the ash concentration in the same radial position increases as temperature elevated,and that as the inlet velocity increases,the separation efficiency firstly increases,then decreases.

Key words: biomass fly ash, cyclone separator, high temperature flow field, particle concentration distribution, numerical simulation