Why This Calculator Helps
Pot distillation looks simple, but ethanol and water do not separate linearly. Vapor is richer in ethanol than liquid, yet the gap changes as the pot becomes leaner. This calculator gives a practical study view of that behavior. It combines equilibrium, operating lines, stage stepping, and Rayleigh balance. The result helps students compare theory with small batch tests.
How McCabe Thiele Logic Applies
The McCabe Thiele method is often used for continuous columns. It is still useful for learning batch or pot distillation. The stair steps show how many ideal contacts would be needed to move from a distillate target toward a residue target. The reflux ratio controls the rectifying line. The feed condition shapes the intersection point. A stripping line is then built to continue the steps toward the pot residue.
Batch Pot View
A pot run also follows Rayleigh distillation. As vapor leaves, the liquid composition drops. The calculator integrates the Rayleigh equation with the selected relative volatility. It estimates final pot amount, recovered distillate, and average distillate composition. These values are best used for planning and comparison, not legal product specification.
Inputs That Matter
Feed composition has the largest effect. A feed near the azeotropic region is harder to enrich. Relative volatility also changes the answer. Larger values create more separation per stage. Reflux improves purity, but it reduces throughput. Tray efficiency converts ideal stages into a practical estimate. The q value is mainly a learning tool here. It shows how thermal condition changes the feed line and stage position.
Reading The Results
The stage table lists each horizontal and vertical step. It reports the vapor composition used, the equilibrium liquid composition, and the next operating line value. The feed stage estimate marks the point where the construction changes lines. Warnings appear when inputs are outside normal ranges or when reflux is below the calculated minimum. Always check real vapor liquid data before designing equipment.
Useful Limits
The model assumes constant relative volatility and ideal liquid behavior. Ethanol water systems can deviate strongly, especially near the azeotrope. Heat losses, entrainment, pressure changes, and column holdup are not included. Treat every output as an educational estimate. Confirm final decisions with experiments and design references.