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CHE 354 Chemical Reactor Design. The General Mole Balance & Ideal Reactors. F A0. F A. What do we do with this term?. Example of Reactor Design. In – Out + Generation = Accumulation. F A0. F A. As D V goes to zero and M goes to infinity:.
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CHE 354 Chemical Reactor Design The General Mole Balance &Ideal Reactors
FA0 FA What do we do with this term? Example of Reactor Design In – Out + Generation = Accumulation
FA0 FA As DV goes to zero and M goes to infinity: Divide reactor into little regions, small enough that intensive variables (CA, T, P) do not vary within. The Generation Term
The General Mole Balance Let’s apply it to the three ideal reactors!
Batch Reactor Perfectly mixed No flow in or out
No flow in No flow out Perfectly mixed Batch Reactor
Batch Reactor And if the volume is not a function of time (constant)
Team Exercise What does design equation (mole balance) look like for a semi-batch reactor - continuous flow of Reactant A, Reactant B, or Product P?
Continuous Stirred Tank ReactorCSTR Perfectly mixed Steady state
Steady state Perfectly mixed CSTR
CSTR What would the design equation look like at startup and with some spatial variations?
Plug Flow ReactorPFR No radial gradients – only axial Steady state
Steady state PFR This is the integral form. Often the differential form is more useful. Take the derivative with respect to volume of each term.
PFR Derivative of a constant is just 0 rA
Example 1-1 Assume isomerization is first order with k = 0.23 min-1 What volume PFR and CSTR are required for 90% conversion and 10 L/min?