heat transfer characteristics of a pipeline for co transport · • inner heat transfer coefficient...
TRANSCRIPT
Technology for a better society 1
Øivind Wilhelmsen1, Michael Drescher1, Armin Hafner1, Gelein de Koeijer2
and Jan H. Borch2
a) SINTEF Energy Researchb) Statoil ASA, Research and Development
Presentation for TCCS-6, Trondheim, June 2011
Heat Transfer Characteristics of a Pipeline for CO2 transport
Technology for a better society
• Motivation• Description of the test facility• Example on results from the experimental investigations• Heat transfer characteristics of a CO2 pipeline surrounded by water• Future experiments• Conclusion and summary
2
Contents
Aim of the work: Improve the knowledge about the heat-transfer to pipelines for CO2 transport with fresh-water as the surrounding substance.
Technology for a better society 3
Motivation The Snøhvit-pipeline is 150 km, surrounded by different media such as sea-water, gravel, rock, with different heat transfer characteristics. The heat transfer will have large effect on the behavior of the pipeline in steady-state operations and potential accidents (such as blow-outs).
153 km, 8 inch300 m
2500 m
300 bar
Ca 150 bar, 5oC
2000 ton/day CO2
Ca 150 bar, 25oC
Orifice atsafe location
DHSV
153 km, 8 inch300 m
2500 m
300 bar
Ca 150 bar, 5oC
2000 ton/day CO2
Ca 150 bar, 25oC
Orifice atsafe location
DHSV
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Process flow diagram of the test facility
Tank
VesselSight glass
Cooling
Heating
Heating
Bypass for direct CO2
vapour return
Pipeline
Surrounding substance
13°
25 Wheater
T
P
P
F
T T
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Heat transfer test chamber
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Positions of temperature elements
Cross-section view
as seen from pipeline inlet
Thermoelement on steel pipeline
Thermoelement on insulation
Thermoelement inside water
CO2 Water
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Example on results from the exp. investigations
-10
-8
-6
-4
-2
0
2
4
6
8
1100 1110 1120 1130 1140 1150 1160Time unit [minute]
Tem
pera
ture
[°C
]
Temperature Pipeline out Temperature Pipeline inAverage water temperature Average temperature on outer insulationAverage temperature on outer steel
Boiling CO2 Steel
Insulation
Water
Temperature
Technology for a better society
• (1) Inner heat transfer coefficient: Free convection/boiling • (2) Thermal conductivity of the steel: Conduction through the pipewall• (3) Thermal conductivity of the insulation: Conduction through the insulation• (4) Outer heat transfer coefficient: Free convection
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Overall heat transfer coefficient through the tube, htot
outisosintot hkrrr
krrr
rhr
h1)/ln()/ln(1 323312
1
3 +++=
(1) (2) (3) (4)
r1
r2 r3
Insulation
Steel
Tout
Tin
Technology for a better society 9
Inner heat transfer coefficient, hin
• Inner heat transfer coefficient varied between 140-180 W/m2K, which corresponds to a free convection regime (left).
B C D
Ts-Tsat
log(hin)
FRE
E C
ON
VE
CTIO
N
NU
CLE
ATE B
OILIN
G
TRA
NS
ITION
BO
LILING
FILM B
OILIN
G
A
Technology for a better society 10
Outer heat transfer coefficient, hout
0
50
100
150
200
250
0 1 2 3 4 5 6
h out
[W/m
2 K]
Experiment No.
Model
Exp
• Outer heat transfer coefficient varied between 170-220 W/m2K.
• Governing regime in the experimental facility is free convection.
• Heat transfer coefficient may be described by the empirical relation developed by Churchill and Chu [1] to within 10% accuracy.
[1] S.W. Churchill and H.H.S. Chu, Int. J. Heat and Mass Transfer, 18, 1049, 1975
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Future experiments
• Experimental investigation and modelling of: • Heat transfer with ice formation around the pipeline• Different surrounding substances such as:
• Salt-water• Gravel• Sand• Etc.
0
10
20
30
40
50
60
0
0,2
0,4
0,6
0,8
1
1,2
0 100 200 300
U [W
/m2K
]
Ice
Thic
knes
s [c
m]
Time [min]
Ice
U
Technology for a better society
• A test facility was built at Statoil’s research centre at Rotvoll in cooperation with SINTEF Energy Research using an actual piece of the Snøhvit-pipeline submerged in a container.
• Initial experiments with tap-water show that the test facility successfully can be used to measure the heat transfer characteristics of the pipeline.
• Outer heat transfer coefficient varied between 170-220 W/m2K and could be described with 10% accuracy by the empirical correlation for free convection by Churchill and Chu [1].
• Inner heat transfer coefficient varied between 140-180 W/m2K and the boiling regime inside the pipeline was governed by free convection.
• Future experiments will investigate the heat transfer characteristics of a pipeline for CO2-transport with ice formation, sea-water, gravel and other surrounding substances.
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Conclusion and summary