芳烃氨氧化双分布器流化床动态特性研究Ⅱ.双分布器影响区的压力波动规律

Investigation on the Dynamic Characteristics of Double Distributor Fluidized Bed for Aromatics Ammoxidation Ⅱ.Pressure Fluctuation Law in the Region Affected by the Double Distributor

在气固流化床冷模实验平台上,对双分布器影响区域内的压力信号进行了测定。采用压力时均值、标准偏差和功率谱密度等特征量分析了不同表观气速、静床高、上下分布器进气流量比以及双分布器间距等条件下的床层压力分布和压力波动特性。结果表明:随着表观气速或静床高的增加,压力波动有所增强,尤其是底部密相区表现更为明显;压力信号呈现低频脉动的特点,表观气速或静床高增大,压力波动主频略有减小,主频相对应能量明显增强;上下分布器的进气流量比和分布器间距对双分布器影响区压力波动影响显著,由气泡生长规律以及气泡尺寸等因素共同作用所决定。

The pressure signal in the region affected by double distributor was measured on a cold mode test platform of gas-solid fluidized bed.Bed pressure distributions and pressure fluctuation characteristics at different superficial gas velocities,initial bed heights,gas flow ratios of double distributor,and distributor spacing were analyzed using time-averaged pressure,standard deviation and power spectrum density.The results showed that the pressure fluctuation increased with superficial gas velocity or initial bed height,especially in the dense phase zone at the bottom of the fluidized bed.The pressure signal was low-frequency pulsation.With the increase of superficial gas velocity or initial bed height,the principal frequency of pressure fluctuation decreased slightly but the signal energy corresponding to the principal frequency increased obviously.The gas flow ratio or spacing of the upper and lower distributors had a significant effect on the pressure fluctuation,which was determined by joint action of bubble growth law and bubble size.