The effect of Type-III Antifreeze Proteins (AFPs) on CO2 ...
Transcript of The effect of Type-III Antifreeze Proteins (AFPs) on CO2 ...
1
The effect of Type-III AntifreezeProteins (AFPs) on CO2 hydrate
formationHongxia Zhou
Carlos Infante Ferreira
Process & Energy Department, TU Delft, Netherland
2
Content
3
What is hydrate?
Clathrate hydrates are ice-likecompounds and have crystallinestructures that are formed withproper combination of small guestmolecules, such as methane,ethane, propane, carbon dioxide,and hydrogensulfides, which aretrapped in cavities of a hydrogen-bonded water framework.
Structure of hydrate
Background
4
1. Hydrate was firstly found by Sir HumphreyDavy in 1810
2. Hammerschmidt defined hydrate as anannoyance for the natural gas industry in 1934
3. Hydrates were found to plug large offshore pipelines in the 1970s.
4. ...
Hydrate history
5
CO2 hydrate=CO2 + H2O
Latent heat: 507 kJ/kg
Phase change temperature:4~8°C
Advantages
Why CO2 hydrate?
Compared with other gases, formation condition is easier toreach
6
Slow down the reaction
Problem specification
Additives:
• Thermodynamic inhibitors• Kinetic inhibitors• Anti-agglomerant
Non-posionous
7
Working principle of AFPs on ice(Kelland, 2006)
8
Set‐up for CO2 hydrate formation.
Notice:1) Cold bath vs Warm bath2) Flow rate control
Experimental Method
9
Phase Equilibrium of CO2 hydrate.
Formation condition of CO2 hydrateYang et al. (2000).
10
wallsolution bath
. . .
expln
Pm i m QlosssU
A T
ln1 1 1
2
oo
i o
pred o w i i
ddd d
U h k d h
ln ln1 1 1
2 2
o io i
i h o
pred o w h h i
d dd dd d d
U h k k d h
No hydrate
With hydrate
1/4
9/16 4/9
0.518*0.36 0.559(1 ( ) )Pr
oRaNu
Churchill and Chu 1975
2/3
0.065 Re Pr3.66
1 0.04 Re Pr
i
cs
i
c
dLNudL
Edwards et al., 1979
11
0 1000 2000 3000 4000 5000 6000 7000 8000 9000100
120
140
160
180
200experimentalpredicted
over
all h
eat t
rans
fer c
oeffi
cien
t, W
m-2 K
-1
Time, s0 1000 2000 3000 4000 5000 6000 7000 8000 9000
100
120
140
160
180
200 experimental predicted
over
all h
eat t
rans
fer c
oeffi
cien
t, W
m-2 K
-1
Time, s
1/4
9/16 4/9
0.518*0.36 0.559(1 ( ) )Pr
oRaNu
0.20.36 0.58*oNu Ra
2/3
0.065 Re Pr3.66
1 0.04 Re Pr
i
cs
i
c
dLNudL
2/3
0.065 Re Pr3.66
1 0.04 Re Pr
i
cs
i
c
dLNudL
Comparison of overall heat transfer coefficient of CO2 water solution
pResults—set-up validation
12
0 5000 10000 15000 20000 25000 30000-50
0
50
100
150
200
250
experimental predicted
over
all h
eat t
rans
fer c
oeffi
cien
t, W
m-2 K
-1
Time, s0 5000 10000 15000 20000 25000 30000
-50
0
50
100
150
200
250 experimental predicted
over
all h
eat t
rans
fer c
oeffi
cien
t, W
m-2 K
-1
Time, s
0.20.36 0.58*oNu Ra
2/3
0.065 Re Pr3.66
1 0.04 Re Pr
i
cs
i
c
dLNudL
0.20.36 0.58*oNu Ra
2/3
0.065 Re Pr2.6
1 0.04 Re Pr
i
cs
i
c
dLNudL
AFPs 5 ppm
Comparison of overall heat transfer coefficient of CO2 water solution with 5 ppm AFPs
13
0 10000 20000 30000 40000 50000 60000 70000 80000 900001000000
20
40
60
80
100
120
experimental predicted
over
all h
eat t
rans
fer c
oeffi
cien
t, W
m-2 K
-1
Time, s
0.20.36 0.58*oNu Ra
2/3
0.065 Re Pr2.6
1 0.04 Re Pr
i
cs
i
c
dLNudL
AFPs 10 ppm
Comparison of overall heat transfer coefficient ofCO2 water solution with10 ppm AFPs
14
0 5000 10000 150002
3
4
5
6
7
8
9
10x 10
-3 hydrate diameter
Time, s
inte
rnal
dia
met
er d
urin
g hy
drat
e fo
rmat
ion,
m No AFPs
0 0.5 1 1.5 2 2.5 3
x 104
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
0.01hydrate diameter
Time, s
inte
rnal
dia
met
er d
urin
g hy
drat
e fo
rmat
ion,
m
5 ppm AFPs
2 21 ( )/ ( )
4h i h c
h
d d LG kg ht
Figure 1:Hydrate diameter change without AFPs
Figure 2:Hydrate diameter change with 5 ppm AFPs
Results—Growth rate
0.5e-3 mm/sTube internal diameter
15
0 1 2 3 4 5 6 7 8 9 10
x 104
0
0.002
0.004
0.006
0.008
0.01
0.012hydrate diameter
Time, s
inte
rnal
dia
met
er d
urin
g hy
drat
e fo
rmat
ion,
m 10 ppm AFPs
Hydrate diameter change with 10 ppm AFPs
0.033e-3 mm/s
16
AFPs /ppm
Supercooling /K
Formation rate / (mm/s)
(this study)
Formation rate / (mm/s)(Uchida et al. 2002)
0 1.00
5 0.72 0.3 0.5e-3 0.519
10 0.72 2.1 0.033e-3 3.63
17
The addition of AFPs changes significantly (0~2.1K) thesupercooling degree of the CO2 water solution needed to initiate theformation of hydrates.
The hydrates production rate can be determined with the additionof AFPs; however, the growth rate of hydrates without the additionof AFPs is too large to measure from the present experiments.
Conclusions
18
The authors would like to thank KoudeGroepDelft/Wageningen for their financial support.