3.1.1 Pressure distribution under different gas superficial velocities
In the beds of type RA and RB, Fig.4 shows that the pressure drop grows with an increasing of the gas superficial velocity. Meanwhile, the pressure drop assumes reverse ā€œCā€ shape with axial position: it has higher value in gas-solid contact zone and lower one in feed/discharge influence zones.
In the bed with gas-solid baffles (type RB), the pressure drop is lower than that in the original bed (type RA); while the pressure drop gradient becomes more uniform (Fig.5). That is because the pinning is weakened in the type RB (section 4.1.2).
In the cross-flow moving bed, the solid velocity have little influence on the gas flow pattern for its relatively small values. The relative gas velocity (differential value of gas and solid velocity) is considered to equal to the gas velocity in this paper. Thus, in gas-solid contact zone, the pressure drop can be roughly computed by Ergun equation (1). The computed values agree well with the experimental results as seen in Fig.4. According to equation (1), the pressure drop is proportional to the bed width L . As the total bed width in type RA keeps the same as it in type RB, its pressure drop varies little because the pinning difference.
(1)