增压流化床热态临界流化速度的实验研究

Experimental Study on Minimum Fluidization Velocity at Elevated Pressure and High Temperature

在内径80 mm的加压热态流化床实验台上,测量不同粒径的石英砂和陶粒砂两类实验物料在压力(0.1～0.6 MPa)和温度(20～800℃)范围内的最小流化速度umf。实验结果表明:在相同的温度下,最小流化速度随压力的增加而减小,而在相同的压力下,温度对最小流化速度的影响随床料种类的不同而有明显的差别。较全面地总结了文献中已有的umf经验关联式,发现umf计算值与本实验值偏差较大。基于厄贡方程和文献中已有的关于最小流化空隙率的实验结论,给出了确定增压流化床热态最小流化速度的合理计算步骤。该方法的预测值和实验值的相对误差在10%以内,为增压流化床反应器的设计和运行提供较可靠的参考依据。

An experimental study of the influence of pressure and temperature on umf was carried out in a bubbling fluidized bed,with an inner diameter of 80 mm in the range of operating absolute pressure 0.1~0.6？MPa and temperature 20~800？℃ with quartz and ceramic sand of different size particles.The results show that： at a given temperature,umf decreases with increasing pressure,at a given pressure,the effect of temperature on umf is dependent on the material.A thorough literature survey on the correlations of umf was presented.It is found that the differences between predicted umf and the experimental value are significant.Based on Ergun equation and conclusion of the reference about voidage at minimum fluidization velocity,an equation about umf was proposed,and then a reasonable calculation steps about umf at elevated pressure and temperature was given.The discrete degree between predicted umf and experimental results is in the range of 10%.It is useful for the design and operation of the pressured fluidized bed reactor.