Murphree Efficiency Formula:
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Definition: Murphree Efficiency of Distillation Column is defined for each tray according to the separation achieved on each tray based on either the liquid phase or the vapor phase.
Purpose: It helps chemical engineers evaluate the performance of individual trays in a distillation column by comparing actual separation to equilibrium separation.
The calculator uses the formula:
Where:
Explanation: The formula compares the actual change in vapor composition between trays to the change that would occur if equilibrium were achieved.
Details: Understanding tray efficiency helps in designing distillation columns, troubleshooting operational issues, and optimizing separation processes.
Tips: Enter the mole fractions for vapor on the nth plate, n+1 plate, and equilibrium value. All values must be between 0 and 1, and yn* cannot equal yn+1.
Q1: What does 100% Murphree Efficiency mean?
A: 100% efficiency means the tray achieves equilibrium between the liquid and vapor phases.
Q2: What are typical Murphree Efficiency values?
A: Typical values range from 50% to 90% depending on tray design and operating conditions.
Q3: How is this different from overall column efficiency?
A: Murphree Efficiency applies to individual trays, while overall efficiency describes the entire column.
Q4: What factors affect Murphree Efficiency?
A: Factors include vapor velocity, tray design, liquid distribution, and system properties.
Q5: Can efficiency exceed 100%?
A: In rare cases, yes, due to mixing effects or measurement errors, but typically not.