Conversion and the Design Equations

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Conversion and the Design Equations
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Conversion, ?A
Conversion expresses the progress of a chemical
reaction in terms of the limiting reactant,
A. If ?A 0 then no A has reacted. If ?A 1
then all A has reacted. ?A Moles A Reacted
/ Moles A Fed (FA0 FA)/FA0 Rearranging FA
FA0 (1 - ?A)
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What is the Limiting Reactant?
Consider the reaction CH3OH 2 O2 ? CO2 2 H2O
A B FA 10 mol/min FB 10
mol/min Which is limiting?
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Batch Reactor
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CSTR
Notice how this term ?/-rA keeps popping up?
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PFR
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Design Equations

• Batch Reactor
• CSTR
• PFR

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Example 1-1 Revisited
CSTR
PFR
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Example
Exothermic Reaction A ? B C
FA0 300 mol/min
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CSTR V FA0?/-rA
V 300.4.2 24 L
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V 300(1-.2).4/2 .2.4 72 L
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CSTR V FA0?/-rA
V 3001.1.9 297 L
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V 72 300.2.5 .9.3/2 142.5 L