
106 Foam Fractionation: Principles and Process Design
column that cuts the falling stream entering one stage and the rising stream
leaving the same stage, we obtain the “operating line,” which is
=χ +
DC
j
T
00
(6.34)
which relates D leaving the top of one stage and C entering from the top of
the same stage. It is noted that the operating line is linear because the upward
and downward moving uxes are constant. This is analogous to the constant
molar overow assumption in the graphical solution to the state of a distilla-
tion column that enables a linear operating relationship. The operating line
has a slope that is equivalent to the re