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 āCā 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)