Figure 1. Experimental setups of the fast (left) and turbulent (right) fluidized beds. The fast fluidized riser had an inner diameter of 0.30 m and was 18.3 m tall, while the turbulent riser had an inner an inner diameter of 0.184 m and was 4 m tall. The fast fluidized bed schematic is reprinted from17, Copyright 2012, with permission from Elsevier. The turbulent fluidized bed schematic is reprinted from21, Copyright 2012, with permission from Elsevier.
The Geldart Group B particles evaluated are listed in Table 1. The particle types included glass, high-density polyethylene (HDPE), polystyrene and sand, with the average diameters (dave ) ranged between 165 – 650 μm and densities (ρp ) between 900 – 2650 kg/m3. The broad particle size distributions (PSDs), with larger standard deviations (σ /dave ), were particles used as received from the vendor. The other particles were pre-sieved to obtain narrower PSDs between two available sieves, which were either used as is (i.e., narrow PSDs) or mixed to form binary mixtures.
Also listed in Table 1 are the operating conditions. The superficial gas velocities (Ug ) used in the fast fluidized bed were in the range of 10 – 17 m/s, which are an order of magnitude greater than that in the turbulent fluidized bed of 1.5 and 1.7 m/s. While the overall solid fluxes (Gs ) were controlled through a slide valve in the fast fluidized bed to range between 50 – 300 kg/m2/s, that in the turbulent bed depended on the superficial gas velocity (Ug ) and ranged between 0.05 – 0.51 kg/m2/s.
Table 1. Geldart Group B materials and operating conditions for the fast 14-19 and turbulent 20,21 fluidized beds.