Ratio of mixed reactor volume to plug flow reactor volume (for equal feed, conversion, positive orders) is always ?
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Answer: C. > 1
Explanation
For positive reaction orders, the volume required for a mixed flow reactor is always greater than that for a plug flow reactor for the same conversion. Option C correctly indicates that the volume ratio of a mixed reactor to a plug flow reactor is greater than one. Plug flow reactors operate at higher average reactant concentrations, achieving target conversions in smaller reaction volumes. Reactor design equations relate reactor volume to reaction kinetics, feed rate, and fractional species conversion. Mixed flow reactors maintain uniform reactant concentrations equal to exit conditions throughout the entire vessel volume. Plug flow reactors feature gradual concentration changes along the length of the reactor tube without backmixing.
Options A and B incorrectly claim that the volume ratio equals one or is less than one for positive reaction orders. A volume ratio less than one would imply that stirred tanks are smaller than tubular reactors, which violates kinetic principles. Option D incorrectly links the volume ratio directly to the reaction order value rather than logical reactor comparisons.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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