增压富氧气氛下临界流化速度的计算研究

Minimum Fluidization Velocity Analysis of Pressurized Fluidized Oxy-fuel Combustion

利用实际气体方程对3种气氛(空气,21O2/79CO2,30O2/70CO2)、两类颗粒(Geldart B和Gel-dart D),在温度范围20～1 000℃,压力范围0.1～4.0 MPa下,计算分析了气氛、粒径、压力和温度对临界流化速度Umf的影响。计算结果表明:随着压力的升高,Umf不断减小;随着温度的升高,Umf先增大后减小,且床层压力越大,达到峰值所需的温度越高。富氧气氛下Umf比空气下小,且粒径越大,Umf越小。模型计算与实验结果吻合较好,为增压富氧气氛下Umf的计算提供了参考。

Influence of pressure, temperature, particle diameter and atmosphere on the critical fluidization velocity Umf are analyzed with real gas equation and parameters as follows： atmospheres （air, 2102/79 CO2, 3002/70 CO2 ）, Geldart B and Geldart D class particle, temperature from 20 to 1 000℃, pressure from 0. 1 to 4.0 MPa. The model result shows that： with the pressure increases, a noticeable decline of Umf is observed. However, for a fixed pressure, Umf increases firstly and reduces afterward with the increase of temperature, and the corresponding temperature of Umf peak becomes higher with increasing pressure. Furthermore, Umf with Geldart D class is smaller compared to Umf with Geldart B class and the oxy-fuel Uzf is much smaller than in air condition. Model results tally well with the experiments at elevated pressure, which provides important reference for Umf calculation under pres- surized oxy-fuel conditions.