Significance of temperature and pressure on minimum fluidization velocity in a fluidized bed reactor: An experimental analysis

This investigation addresses the minimum fluidization velocity (U ( mf )) determination in a refractory insulated fluidized bed reactor (FBR) of 200 mm ID. U-mf is determined with respect to different particle sizes and operating parameters like temperature and pressure up to 900 degrees C and 1 MPa respectively. This study has the main thrust into the establishment of U ( mf ) at elevated temperature and pressure during the thermochemical process, involving uniform mixing of gas-solid by fluidization phenomena at a pilot scale FBR. So, to understand the significance and impact of temperature along with pressure on U-mf , a set of fluidization experiments have been demonstrated in FBR. Two waste materials are abundantly available, similar to Geldart's group-B type bed materials, i.e. Calcined-clay and Coal-ash of an average size of 1.04 and 0.92 mm respectively, and apparent density of 883 and 850 kg/m(3) respectively, have been selected as bed material. Experimental results revealed that U-mf directly relates to particle size and inverse relationship with operating temperature and pressure. Results revealed that U ( mf ) decreases by 59.7% and 59.2% for both bed materials such as Calcined-clay and Coal-ash respectively as the temperature increases from 30 to 900 degrees C at atmospheric pressure. Similarly, U ( mf ) also decreases by 63.3% and 66.0% for bed materials such as Calcined-clay and Coal-ash respectively as the pressure increases from atmospheric pressure to 1 MPa at room temperature. An empirical model has been developed for predicting U-mf at elevated temperature and pressure during fluidization phenomena. The experimental Re-mf shows a good agreement with the predicted Re-mf by using the developed model proving its robustness.