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

wangchao@che.utexas.edu

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