Chapter 12: Steady-State Nonisothermal Reactor Design: Flow Reactors with Heat Exchange

Additional Homework Problems

CDP12-AB

  The elementary gas-phase reaction
     
   

IMAGE 08eq1.gif

     
   

is to be carried out in the various reactors discussed below. The feed, which is at a temperature of 27°C, consists of 80% of A and the remainder inerts. The volumetric flow rate entering the reactor at this temperature is 100 dm 3 /min. The concentration of A in the feed at 27°C is 0.5 mol/dm 3. For 80% of the adiabatic equilibrium conversion:

(a) Calculate the volume of a plug-flow reactor when the reaction is carried out adiabatically.
(b) Plot conversion and temperature as a function of reactor length if the reactor diameter is 5 cm.
(c) Calculate the reactor volume for a CSTR that is operated adiabatically.
(d) Calculate the temperature and conversion profiles down a tubular reactor 0.05 m in diameter that is not insulated. The ambient temperature is 27°C and the overall heat-transfer coefficient is 10 W/ m 2middt K.
(e) Repeat part (d) for northern winter and summer operation.

     
    Additional information:
     
   

image 08eq2.gif

     
    The heat of reaction is a function of temperature, and its value at 300 K is -75,000 J per mole of A. At 300 K,
     
   

image 08eq3.gif

     
    k1 varies with temperature as follows:
   

IMAGE 08eq4.gif

    [2nd Ed. P8-16]