Continuous Stirred-Tank Reactor That Loses Cooling
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The exothermic reaction takes place at steady state in a continuous stirred-tank reactor (CSTR) with a cooling jacket. The initial volumetric flow rate is 2 when the cooling fails at 6 minutes. Once cooling is lost, the reactor temperature starts to increase. Use a slider to vary the volumetric flow rate to try to prevent thermal runaway. Use sliders to change the time at which the flow rate changes and the new volumetric flow rate. The dashed black line shows the behavior if the flow rate is not changed. The solid blue line represents the behavior if the flow rate is instantly changed to the new value. Select a button to plot either the temperature or concentration versus time.
Contributed by: Rachael L. Baumann (August 2013)
With additional contributions by: John L. Falconer and Nick Bongiardina
(University of Colorado Boulder, Department of Chemical and Biological Engineering)
Open content licensed under CC BY-NC-SA
For a CSTR operating at steady-state:
where is the concentration of at steady state (), is the volumetric flow rate until cooling fails (), is the inlet concentration of (), is reactor volume (), is the steady-state reaction rate (), and are the steady-state rate constant and pre-exponential factor (1/min), is activation energy (J/mol), is the ideal gas constant (J/[mol K]), is the steady-state temperature (K), is the molar heat capacity of component (J/[mol K]), and are the inlet and coolant temperatures (K), is the heat transfer coefficient times heat transfer area (J/[K min]), and is the heat of reaction (J/mol).
Mass and energy balances are done to determine concentrations and temperature after cooling has failed:
where is time (min), is the rate of reaction (), and is the rate constant (1/min).
The volumetric flow rate until the valve is adjusted, and then is set with a slider to avoid thermal runaway.
A screencast video at  shows how to use this Demonstration.
 Continuous Stirred-Tank Reactor That Loses Cooling. www.colorado.edu/learncheme/kinetics/CSTRLosesCooling.html.