Prediction of minimum fluidization velocity of gas-solid fluidized beds by pressure fluctuation measurements - Analysis of the standard deviation methodology

摘要

We analyze here an experimental method for the evaluation of U_(ml)-in gas fluidized beds,based on pressure fluctuation measurements in which U_(ml)-is determined by the relationship between the standard deviation of pressure measurements and fluid velocity [M.Puncochar,J.Drahos,J.Cermak,K.Selucky,Evaluation of minimum fluidizing velocity in gas fluidized bed from pressure fluctuations,Chem.Eng.Commun.35(1985)81-87],This was tested in four different particles;Sand,Microcrystalline Cellulose,FCC and Alumina using two circular plexiglass columns with internal diameters of 0.11 m and 0.14 m as the experimental apparatus.Validation of the method was made by comparing our U_(ml)results with those obtained by the fluid-dynamic curve.The experimental data revealed that:(1)the valid range of fluid velocity in the method employed by us is broader than those observed by other authors;(2)the method is suitable for both Geldart A and B solids.Influence of probe location and type of pressure measurement(either absolute or differential)were also analyzed and discussed.