热态临界流化速度研究

Study on Minimum Fluidization Velocity at Elevated Temperature

在内径80mm的鼓泡流化床实验台上，测量了3种粒径范围（0．18-0．315、0．25～0．35、0．28～0．45mm）的石英砂颗粒在室温及高温（250～850℃）下的临界流化速度umf。结果表明：umf在测试范围内基本不随温度变化，随床料粒径的增大而增大。较全面地总结了文献中已有的Umf经验关联式，发现室温下umf计算值与试验值偏差不大，但高温下，2者相差较大。基于试验数据拟合得到新的计算umf的经验公式，公式预测的临界雷诺数Remf与试验测得的Remf的离散程度在10．06％之内，为流化床反应器的设计和运行提供了可靠的依据。

The minimum fluidization velocities （Umf） of silica sand with three particle size ranges （0.18-0.315, 0.25-0.35, 0.28-0.45 mm） were determined at ambient and elevated temperature （250-850℃ ）. Experiments were conducted in a bubbling fluidized bed reactor with an inner diameter of 80 mm. The results show that minimum fluidization velocity is almost stable at the temperature range of 20-850℃, and increases with particle size. A thorough literature survey on the correlations of Umf is presented. It is found that the predicted Remf in literature is similar to the experimental value at ambient temperature, while the differences between them are significant at elevated temperature. A new equation for the prediction of μmr is suggested based on experimental data. The discrete degree between predicted Remf and experimental results is in the range of 10.06%. It is useful for the design and operation of fluidized bed reactor.