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Reactor Design 395

Table 7.11 Summary of Equations for Sizing Packed-Bed Reactors Us-
ing Space Velocities

Rate Equations

V B = F'/p B 'S C w' — orV B = Vvs'/S cv' — or V B = V v '/ S CL' (7.11.1)

Transport

Ap =(Ap)s' L R — (Ap) B » 0.11 psi/ft of bed (0.0252 bar/m) (7.11.2)
Vv' = v s 'A B — v s « 1.0 m/s( 3.28 ft/s) (7.11.3)

Geometric Relations

2
A B = 7iD / 4 — maximumD* 13.5 ft(4.llm) (7.11.4)
V B =W B /p B ' (7.11.5)

L B = VB / AB — LB minimum = 1/2 D
— L B maximum » 25 ft (7.62 m) (7.11.6)

L R = L B + LI' — L! « 3 ft (0.914 m) (7.11.7)

Unknowns

V B - Ap - A B - D - W B - L B - L R

Table 7.12 Calculation Procedure for Sizing a Packed-Bed Reactor Us-
ing Space Velocity______________________________

1. Calculate the bed volume, V B, from Equation 7.11.1.

2. Calculate the bed area, A B, from Equation 7.11.3.
3. Calculate the reactor diameter, D, from Equation 7.11.4. Round off D in 6 in (0.152 m)
increments, starting at 30 in (0.762 m). If D is less than 30 in (0.762 m), use standard
pipe.

4. After rounding off D, calculate the actual bed area from Equation 7.11.4.
5. Calculate the bed length, L B, from Equation 7.11.6.

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