Unequal molal overflow

Dechman [109] illustrates a modification to the usual McCabe-Thiele diagram that assumes constant molal overflow in a diagram that recognizes unequal molal overflow. 

Figure 8-42A-E. Performance analysis of unequal molal overflow for binary systems using Ponchon-Savarit Method.

An effort has been made to present the basic understanding of the method as it applies to systems involving unequal molal overflow, open steam distillation and single flash vaporization in Figures 8-42 and 8-43. 

Rgure 8-43A-C. Graphical solution of unequal molal overflow, binary systems. 

Unequal Molal Flow, 63 Ponchon-Savarit Method, 63 Example 8-21 Ponchon Unequal Molal Overflow, 65 Multicomponent Distillation, 68 Minimum Reflux Ratio — Infinite Plates, 68 Example 8-22 Multicomponent Distillation by Yaw s Method, 70 Algebraic Plate-to-Plate Method,... 

Dechman, D. A., Correcting the McCabe-Thiele Method for Unequal Molal Overflow, Chem. Eng. Dec. 21 (1964) p. 79. 

Unequal Molal Overflow. 1. Ahofoe Feed Plate. The analysis given in the preceding sections was based on constant molal overflow rate, and it is necessary to consider the validity of this assumption. 

Another method of handling unequal molal overflow rates for multi-component mixtures is to make the calculations on the constant molal flow rates and then to calculate the heat load required to give these rates for a few positions in the column. If the heat input to the still is made equal to the largest requirements, and the condenser and tower cross section correspondingly corrected, a conservative design will be obtained. The check points most commonly employed are (1) around the still, (2) the entire section below the feed plate, (3) the feed... 

Binary Distillation 379 Material and Energy Balances 380 Constant Molal Overflow 380 Basic Distillation Problem 382 Unequal Molal Heats of Vaporization 382 Material and Energy Balance Basis 382 Algebraic Method 382... 

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