Dropping the distillate purity from 95% to 92% in an ethanol-water setup results in a/an ____________________ plate requirement?
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Answer: B. Marginal decrease in the number of
Explanation
Relaxing distillate purity from ninety-five to ninety-two percent eases the overall separation constraint. Easier thermodynamic separation requires fewer equilibrium stages to achieve the target product specification. The reduction in required theoretical plates is small because the purity change is relatively minor. Distillation column height and capital cost depend directly on the number of theoretical plates required. Ethanol-water mixtures exhibit non-ideal thermodynamic behavior with an azeotrope near ninety-five percent. Separation difficulty increases exponentially as product purity approaches the azeotropic composition limit.
Process optimization often evaluates whether slightly lower product purity can save significant capital costs. Ethanol distillation plants must balance energy consumption against product purity specifications carefully. Small changes in high-purity specifications drastically alter the required reflux ratio and tray count. No change in theoretical plates is incorrect because lowering purity specifications always reduces stage needs. Major decrease is incorrect because dropping purity from ninety-five to ninety-two is a minor adjustment. None of these is incorrect since a marginal decrease is the correct physical outcome described.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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