Absorption - Introduction to Carbon Capture and Sequestration - page 173

Movie 5.2.1 A single tray
An example of gas fl owing through a plate with liquid. This movie can be viewed at :
http://www.worldscientifi c.com/worldscibooks/10.1142/p911#t=suppl

ideal solution is dependent on the vapor pressure and mole fraction of each
of the chemical components present in the solution, or in the formula:

K CO 2 x CO 2 ,
where p is the pressure in the column, y CO 2 and x CO 2 are the mole frac-
tions of CO 2 in the gas and liquid phase, respectively, and the constant
K is the Henry constant for CO 2 (see Box 5.2.2) . We will use the com-
mon convention that x refers to a concentration in the liquid phase and y
to a concentration in the gas phase. We can get the partial pressure of
the gas by multiplying the pressure ( p ) by the mole fraction of CO 2 in the
gas phase ( y CO 2 ):

y CO 2 p

=

y CO 2 p
The constant 1/K CO 2 characterizes the solubility of CO 2 in the sol-
vent. If a solvent has a high value of K CO 2 , the amount of CO 2 in the
solvent will be lower compared to a solvent that has a lower value of
K CO 2 . We can defi ne a dimensionless constant

p CO 2

=

:

κ

K

CO

2

κ=

p

We know that for water at 25ºC and 1 atm, this dimensionless
constant is 1,600. With this information we can form a very simple