Page 123 - Applied Process Design For Chemical And Petrochemical Plants Volume II

112 Applied Process Design for Chemical and Petrochemical Plants

1.0
0.95
0.90
0.85
0.80
ITT ' 0.75
Ea 0.70
,m m, 0.6 5
L
O 0.60
0.55
' 0
~71: CQ 0.50
eo
, a a, 0.45
0.40
0
0.35
2 0.30
0.25
0.20
0.15
0.10
0.05
'0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.2 1.4 1.6 1.8 2.0 3.0 4.0 5.0 6.0
Values of A, or SI

Figure 8-58. Absorption and stripping factors, Ea or Es vs. effective values & or Se (efficiency functions). Used by permission, Edmister,
W. C., Petroleum Engr., Sept. (1 947) to Jan. (1 948).

treatment to include distillation towers and presents the
same graphical relationships in a slightly modified form.

Absorption: Lean Oil Requirement for Fmed Component
for key component.
Recovery in Fmed Tower [ 181
Multiply by Lo.
1. The rich gas is known, the theoretical trays are fixed
(1 + Z mols/ hr in rich oil/& )
Then, multipy result by (or assumed and corresponding result obtained), the
(1 + Z mols/hr stripped (Step 3)/V, ) operating pressure and temperature can be fixed.
2. For key component and its fxed recovery, E,, read
This is equal to V,. Note that V, also is in the right A, from Figure 8-58 at the fixed theoretical trays, N.
hand side of the denominator, so fractions must be
cleared.

Absorption-Edmister Method

This method [18] is well suited to handling the details 3. Assume: (a) Total mols absorbed
of a complicated problem, yet utilizing the concept of (b) Temperature rise of lean oil (Normally
average absorption and stripping factors. It also allows for 20-40°F)
the presence of solute components in the solvent and the (c) Lean oil rate, mols/hr, Lo
loss of lean oil into the off gas. Reference 18 presents
more details than are included here. Reference 18 is 4. Using Horton and Franklin's [29] distribution rela-
Edmister's original publication of the basic method for tion for amount absorbed (or vapor shrinkage), per
absorbers and strippers. Reference 18 also generates the tray: