Feb 092012
 

*Note: This article is part of a series on a specific research project: Part 1
*Note: This article assumes you have rudimentary knowledge of how a simple distillation column operates. Though much of the basics of the simple model for a distillation column will be covered below, it should not be considered as a stand alone reference.

2.0 Solution Method 2: The Combined Streams Modification of the McCabe-Thiele Method

2.1.0 Defining the Combined Feed/Side Stream

The new stream will be defined as a combined side stream with flow rate \displaystyle M , composition \displaystyle x_M , and fractional quality \displaystyle q_M .

2.1.1 The New Flow Rate

The flow rate for the combined side stream is defined as the following sum

Eq. 2-1) \displaystyle\boxed{M=F+G}

2.1.2 The New Composition

The composition for the combined side stream is defined as the following weighted average

Eq. 2-2) \displaystyle\boxed{x_M=\frac{Fx_F}{M}+\frac{Gx_G}{M}}

This is a classic application of the lever rule.

2.1.3 The New Fractional Quality

The fractional quality of the combined side stream is defined as the following weighted average

Eq. 2-3) \displaystyle\boxed{q_M=\frac{Fq_F}{M}+\frac{Gq_G}{M}}

2.2.0 Defining Relevant Operation Lines and q-Lines

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