Page 205 - Fluid Catalytic Cracking Handbook

Unit Monitoring and Control 173

Regenerator dilute phase catalyst level = 27.0 ft/8.2 m
Regenerator dense phase catalyst bed level = 15.0 ft/4.6 m
3 3
Catalyst density in the regenerator dense phase = 25 Ib/ft /400 kg/m
Regenerated catalyst standpipe elevation = 30.0 ft/9.1 m
Pressure above the regenerated catalyst slide valve = 30.5 psig/210.3 K p
Regenerated catalyst slide valve AP (@ 30% opening) = 5.5 psi/37.9 K p
Reactor-regenerator pressure AP =3. 0 psi/20.7 K p

Also, see Figure 5-9 for a graphical representation of the preliminary
results.
Starting with the reactor dilute pressure as the working point, the
pressure head corresponding to 25 feet (7.6 m) of dilute catalyst
fines is:

3 2 2
(25 ft) x (0.6 lb/ft ) x (1 ft /!44 in ) = 0.1 psig (0.7 K p)

Therefore, the pressure at the top of the stripper bed is:

19.0 + 0.1 = 19.1 psig (131.7 K p)

The static-pressure head in the stripper is:

3 2
(18 ft) x (40 lb/ft ) x (1 ft/144 in ) = 5.0 psig (34.5 K p)
The pressure above the spent catalyst standpipe is:

19.1 + 5.0 = 24.1 psig (166.2 K p)

The pressure buildup in the spent catalyst standpipe is:

26.1 - 24.1 =2 psi (13.8 K p)

The pressure below the spent catalyst slide valve is:

26.1 -4.0 = 22.1 psig (152 K p)

The pressure head corresponding to 28 feet (8.5 m) of dilute catalyst
fines in the regenerator is:

2
3
2
(28 ft) x (1 lb/ft ) x (1 ft /144 in ) = 0.2 psig (1.4 K p)