Packing Characterization-Mass Transfer Properties
Chao WangCarbon Management Project of PSTCAdvisors: Gary Rochelle and Frank SeibertResearch Engineer: Micah Perry6th Trondheim CCS ConferenceJune 15, 2011
Mass Transfer in a Typical CO2 Capture Process
*
2
2
22
2 )(1][
11
CO
CO
lCO
CO
GG cP
akDAmkaH
akaK
++=
kGa
kGa
kLaa
Research objective aeeffective gas-liquid contact area--CO2
capture absorber kGagas film mass transfer coefficient water
wash, gas cooler kLa liquid film mass transfer coefficient
stripper
Objective: -measure ae, kG and kL for novel structured and random packings
- develop a fundamental model can predict ae, kG and kL for novel packings.
Packed Column
ID:0.43m
Packing InformationPackingName
RSP 250 FP 1.6 Y HC
Mellapak2X
RSR #0.5 1 PlasticPall Ring
Type Hybrid High Capacity
60 angle Random metal
Random plastic
Surface Area
(m2/m3)
250 295 205 250 210
Corrugation Angle
N/A 45 60 N/A N/A
Channel Side, S (m)
N/A 0.017 0.02 N/A N/A
Void fraction,
0.92 0.95 0.99 N/A N/A
Effective gas-liquid contact area
Absorption of CO2 into 0.1 N NaOH solution Pseudo first order reaction Liquid phase control
RTZkyy
u
RTZKyy
ua
G
outCO
inCOG
G
outCO
inCOG
e '
)ln()ln(2
2
2
2
=
2
,2'][
CO
LCOOHg H
DOHkk
=
Gas-liquid contact area of MP2X
ae/ap= 0.70L0.125
0.6
0.8
1.0
1.2
0 10 20 30
Frac
tiona
l Are
a, a
e/ap
Liquid Load, GPM/ft2
uG = 4.87 ft/suG = 3.25 ft/suG = 1.95 ft/s
0,4
0,5
0,6
0,7
0,8
0,9
1
1,1
1,2
1,3
0,0001 0,001 0,01 0,1
Frac
tiona
l are
a, a
e/ap
+13%
-13%
9 structured packingsap: 125 500 m2/m3L: 1 15 mPas: 30 72 mN/m
116.0
343/1
p
e )()(34.1
=
P
L
aLg
aa
34
p
31
L
aLg
Tsais area model (Tsai,2010)
Tsai R. "Mass Transfer Area of Structured Packing". The University of Texas at Austin. Ph.DDissertation. 2010
Gas-liquid contact area
MP2X(60 angle)
FP1.6YHC(High Capacity)
RSP250(Hybrid)
RSR#0.5(Metal Random)
1"PPR(Plastic Random)
Tsai area
+20%
-20%
0.4
0.6
0.8
1
1.2
1.4
5.0E-6 1.0E-5 2.0E-5 4.0E-5 8.0E-5
Frac
tion
al E
ffec
tive
Are
a a e
/aP
Generalized Liquid Superficial Velocity uL/aP (m2/s)
Gas Film Mass Transfer Coefficient
Gas film control (SO2/NaOH solution system) Instantaneous reaction Liquid film resistance can be neglected
SO2 concentration is measured by two different range SO2 analyzers. Outlet sample SO2 analyzer can detect 0.1 ppb SO2 can use 10 feet packing
ZRTyyu
ak outin
G
G
)ln(=
e
GG a
akk =
Gas film mass transfer coefficient kG of MP2X
kG = 0.026uG0.77
0.00
0.04
0.08
0.12
0 2 4 6 8
k G, f
t/s
Gas Velocity, ft/s
5.0 GPM/ft210.0 GPM/ft220.0 GPM/ft2
kG summary
FP1.6YHCn=1.05
RSP250n=0.8RSR#0.5
n=0.96
1"PPRn=0.87 MP2X
n=0.73
0.005
0.01
0.02
0.04
0.5 1 2
k G/(
m/s
)
Gas Superficial Velocity uG (m/s)
kG=kG,uG=1m/s*(uG/1)n
Modified Rocha-Bravo-Fair1 kG Model
33.088.0 )())((032.0GG
G
GP
GLEGE
GP
G
Dauu
Dak
+
=
33.08.0 )())((054.0GG
G
G
GLEGE
G
G
DSuu
DSk
+
=
sin)1( LGS
GE huu
=
1.Rocha JA, Bravo JL, Fair, JR. Distillation Columns Containing Structured Packings: A Comprehensive Model for Their Performance.2. Mass-Transfer Model. Ind Eng Chem Res. 1996;35:16601667.
kG model
ShG=0.0317*ReG0.88ScG0.33
+20%
-20%
2
4
8
16
150 300 600
ShG=k
Gd e
q/D
G
Re=uGEGdeq/G
MP2X
FP1.6YHC
RSP250
Average Deviation16.2%
Liquid film Mass Transfer Coefficient
)/ln( LoutLinLL ccZuak =stripping:
Liquid film control (Air/Toluene/Water system)
No chemical reactions
Mass transfer resistance mainly in liquid film
e
LL a
akk =
Liquid film mass transfer coefficient kL of MP2X
kL = 2E-05uL0.6809
0E+0
1E-4
2E-4
3E-4
0 10 20 30
k L, f
t/s
Liquid Load, GPM/ft2
uG = 4.87 ft/suG = 3.25 ft/suG = 1.95 ft/s
kL summary
FP1.6YHCn=0.76
RSP250n=0.71
RSR#0.5n=0.811"PPR
n=0.63
MP2Xn=0.70
8E-6
2E-5
3E-5
6E-5
5.0E-6 1.0E-5 2.0E-5 4.0E-5 8.0E-5
k L/(
m/s
)
Generalized Liquid Superficial Velocity uL/aP (m2/s)
kL=kL,uL=0.0067*(uL/0.0067)n
Brunazzi2 dimensionless kL model (1997)
Consider the mixing of liquid phase occurs at junctions. Kapista number Ka
Includes the flow path length factor, which is Hel/sin Includes packing geometry factor S, liquid film thickness
2.Brunazzi E, Paglianti A. "Liquid-Film Mass Transfer Coefficient in a column Equipped with Structured Packings." Ind Eng Chem Res. 1997;36:3792-3799
C
B
L KaGzASh =
elLL H
ScGz sinRe=L
LELL
SU
=Re
LL
LL D
Sc
=
gKa
L
L4
3
= 5.0)sinsin
3(
L
LS
L
L
hU
g=
A=409, B=0.5, C=0.09
sinLLS
LE huu =
kL model
ShL=409*Gz0.5Ka-0.09Average Deviation 20.2%
+20%
-20%
100
200
400
800
1600
15 30 60 120 240 480
ShL=
k Ld e
q/D
L
Gz=ReLScLsin/Hel
MP2X
FP1.6YHC
RSP250
Conclusions ae is a function of L, ~uL0.155, not a function of G ,
Tsais area model:
kG ~uG0.88, not a function of uLModified RBF kG model:
kL ~uL0.74, not a function of uGModified RBF kL model:
116.03/43/1 ])1*()[(42.1p
L
p
e
aAQg
aa
=
33.088.0Re*0317.0 GGG ScSh =
09.05.0*409 = KaGzShL
Thank You
Chao Wang
Packing Characterization-Mass Transfer PropertiesMass Transfer in a Typical CO2 Capture ProcessResearch objectivePacked ColumnPacking InformationEffective gas-liquid contact area Gas-liquid contact area of MP2XSlide Number 8Slide Number 9Gas Film Mass Transfer CoefficientSlide Number 11Slide Number 12Modified Rocha-Bravo-Fair1 kG ModelSlide Number 14Liquid film Mass Transfer CoefficientSlide Number 16Slide Number 17Brunazzi2 dimensionless kL model (1997)kL modelConclusionsThank You