Binary distillation constant molal overflow

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... 

Abstract This document creates a McCabe-Thiele Diagram for a binary distillation using the constant molal overflow assumptions. It assumes ... 

Consider the packed distillation tower shown in Figure 16-1. Only binary distillation with constant molal overflow (CMO) will be considered. Let A be the more volatile conponent and B the less volatile component. In addition to making L/V constant and satisfying the energy balances, CMO automatically requires equimolal counterdiffusion, = -Ng. Thus, CMO sinplifies the mass balances, eliminates the need to solve the energy balances, and simplifies the mass transfer equations. We will also assume perfect plug flow of the liquid and vapor. This means that there is no eddy mixing to reduce the separation. 

Introduction. In Section 11.4B the McCabe-Thiele method was used to calculate the number of theoretical steps or trays needed for a given separation of a binary mixture of A and B by rectification or fractional distillation. The main assumptions in the method are that the latent heats are equal, sensible heat differences are negligible, and constant molal overflow occurs in each section of the distillation tower. In this section we shall consider fractional distillation using enthalpy-concentration data where the molal overflow rates are not necessarily constant. The analysis will be made using enthalpy as well as material balances. 

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