As the reflux ratio is reduced, what happens to the_________________?
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Answer: B. Number of plates increases
Explanation
Reducing the reflux ratio lowers the internal liquid traffic inside the distillation column. This decrease in liquid traffic reduces the concentration driving force needed for phase separation. Consequently, a much larger number of theoretical plates becomes necessary to achieve separation. Reflux ratio is defined as the ratio of liquid returned to the column top to distillate withdrawn. Theoretical plates represent idealized stages where vapor and liquid streams reach thermodynamic equilibrium. Higher reflux ratios promote better contact between countercurrent vapor and liquid phases.
Distillation column design balances operating costs against capital expenses for column height. Lower reflux ratios reduce energy consumption in the reboiler but significantly increase tower height. Chemical engineers optimize this parameter to minimize overall plant operating and construction costs. Separation efficiency decreases rather than increases when the internal reflux ratio is reduced. The number of actual and theoretical plates required increases rather than decreases. Column diameter is primarily determined by vapor velocity and flooding limits rather than reflux ratio.
- Subject
- Engineering
- Category
- Chemical Engineering
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- —
- Difficulty
- medium
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