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Theme A6:CO2 Transport Infrastructure
Newcastle UniversityP.N. Seevam, J.M.Race , M.J.Downie,
• Effect of impurities on physical properties of CO2 and equations of state
impacts pipeline design – pipeline hydraulics, avoidance of hydrate formation & two phase flow etc
• Transient conditions (e.g. blow down , start up & shutdown) need special consideration for avoidance of two-phase conditions
• HSE/ Regulatory/Design codes issues needs to be defined as it is important in pipeline routing.
• Risk of long running brittle fractures (due to cooling effects around leaks) and long running ductile fractures (due to phase changes during depressurisation). Crack arrestors fitted in USA. Impurities?
• Network design, development, operation and management (metering & custody transfer etc)
• Strategy for development of infrastructure – how much CO2 to collect, when. Top 16 sources account for around 40% of CO2 output
Pipeline Issues
Offshore Pipelines: Additional Issues
• No experience of transporting CO2 for long distances offshore. The only subsea CO2 pipeline that has been laid is the Snohvit pipeline
• Pressures typically 50 to 200 bar for existing offshore pipelines. Maintaining sufficiently high pressures for delivery specifications could be a problem
• Availability of existing infrastructure- Trunk lines etc• Upgrading existing infrastructure for EOR• Integration of onshore and offshore networks• Decommissioning Vs. Re-use• Pipeline integrity and fitness for purpose in re-use
• Hydrostatic pressure may be mitigating factor with regard to brittle fracture
• Impurities introduce variables in most aspects of CO2 transport.
D0
50
100
150
200
-100 -72 -44 -16 12 40
Temperature / degC
Pres
sure(
Bar)
Vapour CO2
Liquid CO2
Solid CO2
Dense Phase CO2
Phase Diagram for pure CO2
Supercritical
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Pipeline Operating Region
Existing CO2 Pipelines for EOR in the USA: HIGH PRESSURE(140-200bar) ONSHORE (dessert terrain) and mostly NATURAL
sources solely for EOR
Operating Conditions
CO2 properties are unusual compared to otherfluids transported near the critical point by pipeline: Pipeline temperatures for nitrogen and methane are well
above their critical point . Oil and water operate at pressures lower than their
critical values.
No
Ph
ase C
han
ge
CD
0
20
40
60
80
100
120
140
-200 -67 67 200 333 467 600
Temperature / degC
Methane
Oil (MW 353)
Nitrogen
WATER
CO2
Ethylene
C (374C, 221Bar)
(31C,73.8bar)
(539C,9.9bar)
(-82.7C,40.7bar)
(-147C,34bar)
Pre
ssur
e (b
ar)
(9C,50.2bar)
Phase Envelopes for Various Fluids transported by pipelines
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Pipeline Operating
Region Impurities Introduce
more variables for CO2
Effect of Impurities on CO2 Pipeline Transport
Pipeline risk modelling E.g. Dispersion modelling , Health and safety.
Hydraulics - 2 phase flow, transients, hydrates , pipeline capacity and compression
Non metallic components Elastomers. CO2 diffuses into
elastomers under pressure and pressure release may cause
explosive decompression and blistering." All elastomers are permeable to CO2”; use high
durometer elastomers (>90).Pipeline Inspection Tools
Impurities could potentially change the diffusion characteristics.
Fracture due to slow decompression wave speed. The Decompression characteristics depend on gas composition
Impurities affect water solubility and consequently corrosion.
Power station impurities such as SOx, NOx and Ar have not been transported
EOR and Storage have different requirements.
Change in width & shape of phase envelope-2 phase flow region
Critical temperature and pressure .
Supercritical area reduction as % impurity increases.
Impurity Interaction Solid Freeze out
components (hydrates) Liquid region
reduction/elimination
Physical Properties – Phase Envelopes for CO2 with Impurities
CC
C
C
0
10
20
30
40
50
60
70
80
90
100
-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60
Temperature /°C
pure CO2
95%CO2+5%N2
90%CO2+5%N2+5%CH4
90%CO2+5%N2+5%NO2
95%CO2+5%NO2
95%CO2 +5% H2
Pres
sure
(bar
)
Src: US Dept. of Interior
Recompression Distance Vs % Impurity
5% H2 is not economical in terms of number of compressor stations
Compressor Power is also effected by amount , type and combination of impurities.
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0
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
320
109876543210
% impurity
H2H2SCH4NO2SO2O2N2ArCO
Recom
pre
ssio
n d
ista
nce (km
)
Effect of Impurities on Pipeline Capacity
CompositionMass
Flow rate(kg/s)
Vol. Flow rate
(m3/s)
% Deviation from pure CO2
Mass Flow Rate
Vol. Flow Rate
Pure CO2 85.68 108.10 - -
95% CO2 + 5% N2 81.92 44.68 -4.39 -58.67
90% CO2 + 10% N2 68.65 38.08 -19.88 -64.77
95% CO2 + 5% CH4 82.11 45.37 -4.17 -58.03
90% CO2 + 10% CH4 78.01 44.56 -8.95 -58.78
95% CO2 + 5% H2 76.48 43.17 -10.74 -60.06
90% CO2 + 10% H2 56.19 33.22 -34.42 -69.27
95% CO2 + 5%Ar 83.7 45.02 -2.31 -58.35
90% CO2 + 10%Ar 80.68 43.63 -5.84 -59.64
90% CO2 + 5% CH4+ 5% N2 77.5 43.63 -9.55 -59.64
90% CO2 + 5% H2+ 5%Ar 62.02 35.07 -27.61 -67.56
90% CO2 + 5%Ar + 5% CH4 79.32 44.10 -7.42 -59.21Calculation is done for a pipeline segment with its flow adjusted to operate at a pressure drop of 0.0001bar/m with an internal diameter of 15”(OD=16”) and an ambient temperature of 5C
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Diameter as a Function of CO2 Mass Flowrate for variable Inlet Pressures
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60 70 80 90 100
Mass Flow Rate (Mt/Yr)
150 bar
175
200
225
250
Dia
met
er "
100km CO2 pipeline with outlet pressure of103 bar.
Example 2030-2050 EU scenario
40 inch trunk pipelines,250 miles at 100 bar with consideration to erosional velocity pipeline maximum capacity,
pure CO2 , compression occurs when pressure falls to 80 bar.
5.316.0
5.914.67.9
24.0
8.8
21.910.6
32.0
11.7
29.2
0
10
20
30
40
50
60
70
80
pipelines pumps pipelines pumps
2000 1800
Flow Rate (kg/s)
No
of
Co
mp
/pip
elin
es
20 Gt scenario
15 Gt Scenario
10 Gt Scenario
Conclusions
Design and operation of CO2 pipelines requires careful consideration due to the unique properties of supercritical CO2 both with and without impurities. The type, combination and quantity affects the physical & Transport properties of CO2 ( density & compressibility - product metering, compression, water solubility and flow assurance affected etc
Recompression Distance ,Compressor power and pipeline capacity are directly affected by the type, combination and quantity of impurities.H2 having the greatest impact. Offshore costly. Generally, 2-Phase region , Tc & Pc increases with increasing amount of impurities thus reducing operating margin of pipeline. Initial inlet pressure needs to be increased to reduce the number of pumps and compressors
Constraints are placed on CO2 pipeline infrastructure by the requirement to minimize cost, maintain reliability, and sustaining flexibility of operation with changing composition, upsets, sales and supply, the capture of CO2 for sequestration could possibly introduce high levels of impurity to break even between CAPEX and OPEX.
Network analysis, transient flow (particularly from variable sources), flow assurance due to the cyclic operation of power plants and risk assessment will also have to be addressed if CCS is going to be implemented. This work is on-going at Newcastle University.
The infrastructure development varies between scenarios. Important in meeting targets in a cost effectively.
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Thank You
Summary of Progress Update at Newcastle.
Technical & Regulatory requirement (Completed): Fundamental knowledge of hydraulics have been
established. Model validation with real-time pipeline data. Regulations and design codes.
Input data into scenario models which include source and sinks – Transport scenario building (ongoing)
Identification of sources and sinks - large sources will be chosen. Awaiting input for sinks.
Material issues Network dev. and mgmt Existing Infrastructure – availability in the North Sea
Update on analysis and issues………..
Density – CO2 with 5% Impurity
0
200
400
600
800
1000
1801601401201008060402010
Pure CO2HydrogenNitrogen DioxideNitrogenArgonHydrogen SulphideOxygenSulphur DioxideCarbon MonoxideMethane
Pressure (bar)
Contacts
Patricia Seevam – Research [email protected]
J.M. Race – Lecturer in Pipeline Engineering [email protected]
M.J. Downie – Professor of Technology in the Marine Environment [email protected]
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