xercise 6.8: CSTR ignition onsider the CSTR parameter values listed in Table 6.1 and the steady-state x,T versus sidence time plots in Figures 6.7 and 6.8 . (a) Write down the dynamic CSTR equations for the adiabatic reactor. How many parameters are there and what are their values? Choose consistent units. (b) Choose a residence time of =10min. According to Figures 6.7 and 6.8 , how many steady-state solutions are there at this residence time? What are the stable (cA,T) steady-state values and what are the unstable ones? You can just read these off the plots. Next simulate the dynamic reactor. Choose as initial conditions for cA and T, values near the lower-branch and upper-branch steady states. Simulate the reactor for a time long enough for it to reach steady state. Check that the dynamic simulation converges to a steady state consistent with Figures 6.7 and 6.8 (this is your program debugging check). Once you are sure the program is working correctly simulate the reactor starting from cA=cAf,T=Tf. Increase only the initial temperature and simulate again. How warm can the reactor be started before it ignites and reaches the upper branch steady state instead of the lower branch. Hand in plots of cA(t) and T(t) starting one degree below and above this critical temperature. (c) If it were advantageous to operate at an unstable steady state, how might you modify the reactor design to stabilize the steady state? Sketch your control scheme. Be sure to show and label clearly your sensor and actuator (if you are interested you can simulate the controlled reactor and see what controller gain is required to achieve stability). (d) Change the residence time to =32min. How many steady-state solutions are there for this residence time. Start the reactor from the feed conditions and simulate for 1000min. Does anything unusual happen? Describe what the reactor is doing. Does your simulation point out any safety issues? Can you think of a less violent method to start up the reactor? What values of (cA,T) are you trying to avoid during start up