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Concept: Separating Condensible and Non-Condensible Gases
Context: Condensation of H2O: Pure H2O vs. H2O in air
Today: Increase total P at constant T – Red PathsMap Landmarks & Labels – Green
Lecture 30: Decrease T at constant total P – Blue Paths
EngrD 2190 – Lecture 31
Prelim 3: Tuesday 11/23, 7:30-9:30 p.m., 245 Olin Hall.Graphical Modeling for Mass Balances - Part 2:
translating thermodynamic maps: T-(x,y) to x-y, for example.operating lines for multistage absorbers and strippersoperating lines for multistage distillationphase maps for pure substances - separating condensible vapors
from non-condensible vapors.design using single-stage and countercurrent multi-stage units -
may include use of T-(x,y), P-(x,y), H-(x,y)and ternary diagrams.
Open book, open notes, open exercise solutions.Bring a calculator and a ruler. Graphing calculators are allowed. Laptops allowed as for Prelim 1.
Practice exercises: 4.40, 4.47, 4.48, 4.58, 4.59, 4.69, 4.70, 4.77, 4.81and 4.109. Solutions are posted.
100°C 100°C 100°C
Recap from Lecture 30
Pure H2O
Pure H2O (no air)
Decrease Tat constant P
200°C100°C
1
23
4
5
Recap from Lecture 30
15.3 atm 15.3 atm 15.3 atm
pressure measured –agrees with P-T phase map
Pure H2O
Pure H2O (no air)
liquid+vapor
solid+vapor
solid+liquid
Decrease Tat constant P
12
3 45
1
2 3
Increase total Pat constant T
4
5
Pure H2O (no air)liquid
Decrease Tat constant P
1234
5
Increase Pat constant T
1
2
path slope 1
slope 1
34
tie line at 200°C
vertical path;liquids are Incompressible. 5
Pure H2O (no air)
Decrease Tat constant P
200°C100°C
1
23
4
5
Increase Pat constant T
1
23
4
5
H2O + air
from P-T phase map
1 atm5 atm
atm 5
)atm 1(20
2080
vapormols OH vapormols total
OH2
total 2
PP
atm 05
)atm 1(6.1
6.180
vapormols OH vapormols total
OH2
total 2
PP
1 atm50 atm
open valve,drain liquid
1 atm50 atm
H2O+air
liquid+vapor
solid+vapor
solid+liquid
Decrease Tat constant total P
12
3
4 5
Increase total Pat constant T
1
2 3 4
5
10
5
50
H2O + airliquid
Decrease Tat constant P
12
3 45
tie line at 61°C
tie line at 18°C
Increase total Pat constant T
1
2 path slope 13
10
10tie line at 100°C
4
5
partial of H2O
H2O + airDecrease Tat constant P
200°C100°C
12
34
5
Increase total Pat constant T
1
23 4
5
partial
partial