Page 331 - Modelling in Transport Phenomena A Conceptual Approach

8.5. MASS TRANSPORT WTH CONVECTION 311

01 1
0 300 600 900 1200 1500

The slope of the stmight line is - 9.387 x m2/ s. Hence,

The total molar concentration is

P
c= - 1 = 0.041 kmol/ m3 (9)
-
RT - (0.08205)(25 + 273)
Substitution of the values into Eq. (8) gives the diffusion coefficient as
r 1
879
12 (0.041)(78) In ( 760 )
VAB = 9.387 x lo-’
760 - 94.5
= 9.72 x m2/ s

8.5.2 Diffusion Through a Stagnant Liquid
Consider a one-dimensional diffusion of liquid A through a stagnant film of liquid
B with a thickness L as shown in Figure 8.36. The mole fractions of A at z = 0
and z = L are known. As an engineer, we are interested in the number of moles of
species J1 transferring through the film of t3 under steady conditions.