Profiles

3-24 • Modeling a Sour Water Stripper Getting Started - Electrolytes

The Profiles | Properties sheet reports the actual composition

of molecular components and ions.

1 Select the Properties sheet. You may need to click the arrows

at the right end of the row of tabs to reach it.

Consider the results for Stage 1. The true composition of NH3

and NH4+ sum to 0.03147 on Stage 1. This value is slightly

different from the apparent mole fraction of NH3 reported on

the Compositions sheet: 0.03138. This slight difference is

caused by the solution chemistry.

In general, the total number of moles is not conserved by

solution chemistry. In this simulation, the fourth equilibrium

reaction consumes 3 moles of reactants and generates two

moles of products:

+ ⇔ + + − 2 2 3 3 CO 2 H O H O HCO

The total number moles on an apparent component basis will

be different from the total number of moles on a true

component basis. Thus XNH3 (apparent basis) is not exactly

equal to XNH3 (true basis) + XNH4+ (true basis).

The liquid composition of apparent NH3 on stage 1 is:

XNH3 = 0.03138

2 Select the Compositions sheet.

3 In the View field, select Vapor.

The vapor composition of apparent NH3 on stage 1 is:

YNH3 = 0.21116

From these two values, you can calculate a K-value for NH3 on

stage 1:

K = YNH3/XNH3 = 6.73

To View these

Дата добавления: 2015-08-20