Additional Homework Problems

CDGA 6-2A

(CSTR train) The elementary liquid-phase reaction

A + B C

is to be carried out in a CSTR with three impellers. The mixing patterns in the CSTR are such that it is modeled as three equal-sized CSTRs in series. Species A and B are fed in separate lines to the CSTR, which is initially filled with inert material. each CSTR is 200 dm³ and the volumetric flow to the first reactor is 10 dm³/min of A and 10 dm³/min of B.

1. What is the steady-state conversion of A?
   
   
2. Determine the time necessary to reach steady state (i.e., when C_A exiting the third reactor is 99% of the steady-state value).
   
   
3. Plot the concentration of A exiting each tank as a function of time.
   
   
4. Suppose that the feed for species B is split so that half is fed to the first tank and half to the second tank. Repeat parts (a), (b), and (c).
   
   
5. Vary the system parameters, v₀, V, k and so on, to determine their effects on startup. Write a paragraph describing the trends you found which includes a discussion of the parameter that most effects the results.

Additional Information

C_A0 = C_B0 = 2.0 mol/dm³
k = 0.025 dm³/mol/min

[3rd Ed. P4-29]