Plug Flow Reactor with Multiple Reactions
THE DESIGN EQUATION FOR A PFR
is written for each component and the set of ODE's is solved subject to the initial conditions. The rate of initial production of each component is:
THE PROBLEM STATEMENT
Allyl chloride is to be produced in a 12-ft. long 2-in ID tube operating at isothermal PFR. The feed is a 4:1 molar ratio of propylene to chlorine and enters at a feed rate of 0.85 lbmole/hr and 2 atm of pressure. The reactor pressure is assumed to be constant.
The rate constants have units of lbmoles/(hr-ft3-atm2) and are:
where T is in degrees Rankine and R is in Btu/(lbmole ºR). The rate expressions are
THE QUESTIONS
- List the set of ODE's that are needed to determine the molar flowrates within and exiting the reactor. Define all variables used and specify values for all constants and initial conditions. Study the reference plot to view the changes in the molar flowrates of Cl2, C3H5Cl, and C3H6Cl2.
- Run the program to explore the effect of changing the temperature on the molar flowrates of Cl2, C3H5Cl, and C3H6Cl2, and on the selectivity. The selectivity is defined as the ratio of molar flowrates for C3H5Cl/ C3H6Cl2. Why is the selectivity constant within the reactor? Increase and decrease the temperature. Why did the temperature have the effect that it did? Can you generalize the effect of temperature on selectivity for other multiple reaction systems?
