Page 492 - Elements of Chemical Reaction Engineering Ebook

Sec. 8.3 Nonisothermal Continuous-Flow Reactors 463

2. The reactor is surrounded by a heat exchanger where the heat-transfer coeffi-
cient is 1 10 J/m2 - s K, and the ambient temperature is 1 150 K.
Thie inlet temperature and pressure are the same for both cases at 1035 K and 162 kPa
(1.6 atm), respectively. Plot the conversion and tempeiarlre along the length of the
reactor.
Solution
Let A = CH,COCH,, B = CH2C0, and C = CH, . Rewriting the reaction symboli-
cally gives us A+B+C
1. Mole balance:

(E8-7.2)
2. Ratehw:
(E8-7.3)
3. Stoichiometry (gas-phase reaction with no pressure drop):

(E13-7.4)

4. Combining yields

(E13-7.5)

(ER-7.6)

To solve the differential equation above, it is fKst necessary to use the energy
balance: to determine T as a function of X.
5. Energy balance:

CASE I. ADIABATIC OPERATION
For no work done on the system, Ws = 0, and adiabatic operation, Q = 0 (Le.,
U = 0), Equation (8-56) becomes

where in general

For acetone decomposition

Ac~ = o~B+ayC-~r,
Equivalent expressions exist for A$ and Ay.