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A heat exchanger and a controller are to be
added to the ammonium nitrate reactor discussed in Problem P9-3. The reactor
temperature is to be controlled by manipulating the coolant flow rate,
in the heat exchanger. The ambient temperature at the time the controller
is turned on is 970°R. The product of the heat-transfer coefficient
and heat-exchanger area is UA = 10,000 Btu/h °F.
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The controller is to be a PI controller with an integral
time, 
of 1 h and a gain of -4.5°. A sudden upset causes the reactor temperature
to rise to 1000°R, which is 25°R above the set point. |
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For each of the following three cases, plot the reactor
temperature and mass in the reactor, M, as a function of time.
[Hint: First show that the energy balance can be written as |
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(a) Consider Mconstant at 300 lb.
(b) Calculate M from a mass balance, that is,
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The set-point of the mass in the tank is 325 lb.
(c) Consider no control by setting the controller gain equal to zero
(i.e., kC = 0.)
(d)Vary kCand
describe what you find.
(e) Vary UA, C
,,
and so on, and describe what you find.
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