Advanced CO2 consequence modelling
for safe CCS
Agenda
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01
Introduction
02
CO2 releases to the atmosphere
03
CO2 releases under water
04
DNV’s expertise in CCS
DNV ©
Introduction
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CCS: Carbon capture and storage in brief
• CCS: important carbon abatement technology
• Capture: millions of tonnes of CO2 from significant emitters
• Transport: pipelines or ships before being injected
• Storage: deep into the earth’s rock formations
Source: Econnect Energy
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Operational and planned capture capacity
[Mt of CO2 per year]
Properties of carbon dioxide (CO2)
• Colourless, odourless & invisible gas at standard
conditions
Pure CO2 Phase Diagram
• “Dense phase”: means liquid or supercritical CO2
Triple point
(5.18 bara, -56.6°C)
• Supercritical: viscosity similar to gas, density
closer to a liquid
• Dissolves in water to form carbonic acid
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ation
Satur
Line
Critical point
(73.8 bara, 31.1°C)
Gas phase
• Only gas or solid phase at atmospheric pressure
• Solid CO2: known as “dry ice” (-78°C)
Liquid phase
Solid phase
Melting Line
• Four phases: gas, liquid, solid and supercritical
Pressure (bar)
• Heavier than air; not reactive or flammable
ion
ine
L
at
m
bli
Su
Supercritical
phase
Atmospheric Pressure
Sublimation temperature at
atmospheric pressure: -78.5°C
Temperature (°C)
CO2 hazards
• Asphyxiant when displacing oxygen in air
• Impacts depend on location specific factors
• Threat to life at concentration of 15% due
toxicological impact
• Animals may suffer hypercapnia and
asphyxiation
• Immediately Dangerous Life or Health
(IDLH) of 4%
• Dissolves to form carbonic acid
• Absorbed in soil can cause vegetation die-off
• Rapid expansion and phase change creates
high velocity, low temperature 2-phase jet
• Personnel exposed to cold jet of gas with
entrained solid particles
• Brief exposure harms delicate tissues
• Prolonged exposure: cold burn and frostbite
• Inhalation causes severe lung damage
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CO2 HAZARDS
• Reduced visibility within CO2 water vapour
cloud
• Stopping of internal combustion engine
• Projectiles upon containment failure
Hazard analysis software for safe CCS
Phast
Control CO2 hazards by
modelling discharge,
dispersion and toxic effects
KFX
Advanced CO2 discharge and
dispersion modelling using
computational fluid dynamics
Image provided by the Global CCS Institute
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CO2 releases to the atmosphere
Source term and dispersion modelling
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Dispersion of CO2 in the atmosphere
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100 mm pure CO2 release – video
Dispersion of CO2 in the atmosphere
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100 mm pure CO2 release – video
Phast™ consequence modelling
CO2 releases to the atmosphere
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Phast™ modelling
LOC scenario
Discharge
Weather
Toxic
Dispersion
Radiation
Explosion
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Phast capabilities for modelling CO2
• Release scenarios – source term:
• Pressure vessels: leaks, catastrophic ruptures
• Long pipelines (buried or above ground): punctures, full-bore ruptures
• Dispersion: unified dispersion model (UDM)
• Toxic effects: concentrations, probit, lethality levels
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Phast extensions for solid phase CO2
• Phast generally handles fluids, not solids
No solid CO2 modelling Solid CO2 modelled
• Phast solid extensions for CO2 more than 15 years ago
• Discharge: Solid effects accounted for in expansion from
vessel orifice/pipe exit to atmospheric pressure
Atmosphere
• Dispersion: solid/vapour equilibrium, sublimation
• No deposition of solid CO2 on the ground
Vessel
Pipe
Vapour
Liquid
Flow
Expansion zone
https://www.sciencedirect.com/science/article/abs/pii/S0950423009001351
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Vapour
Liquid
Solid
Vapour
Solid
Validation of Phast for CO2
• Comparing Phast predictions with experiments is a crucial activity
• DNV Spadeadam Research and Testing facility in Cumbria in the North of England
• Numerous CO2 release experiments over the years
• Phast validation: discharge and dispersion predictions compared against these experiments
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Experiments
Scenario
Phase
Hole size
Year
BP
Orifice, horizontal
Dense, Supercrit
6-26 mm
2006-7
Shell
Orifice, horizontal
Dense, Supercrit
6-25 mm
2010-11
CO2PIPETRANS
Long pipe and
orifice, horizontal
Dense
10-150 mm
2012-13
COSHER
Buried long pipe
Dense
203 mm
2013
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Phast CO2 pipeline releases
• Phast pipeline release modelling
• Fluid phases: liquids, vapour, super-critical
• Accident scenario: full-bore rupture and
partial breaches of a long pipe
• Transient modelling
• Accounts for valve action and finite pumped
throughput
• Subsea pipeline releases not modelled
• Pipelines can be buried - crater effects
Image provided by the Global CCS Institute
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Phast buried CO2 pipeline releases
• Phast models buried CO2 pipeline releases
• Depth of soil cover and type of soil key inputs
• Crater effects: dimensions, modified velocity and CO2 solid fraction
• Stalling plume / gas blanket effect
• Improved modelling released in Phast 8.9 June 2023
• Based on large-scale COSHER experiments
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Crater from COSHER experiments
International Journal of Greenhouse Gas Control 37 (2015) 340–353]
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Buried CO2 pipe releases: COSHER validation
Maximum arcwise concentrations – observed vs predicted
COSHER 1 (wind~4.7m/s)
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COSHER 2 (wind~1.9m/s)
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Do you recognize these photos?
• Not a controlled experiment
• COSHER large scale experiment was 8”
• Accidental rupture of 24” CO2 pipeline near Satartia in
2020
• Leak size 9 times larger for the 24” Satartia rupture
• Operator’s hazard assessment did not identify the scale of areas that
could be affected
https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2022-05/Failure%20Investigation%20Report%20-%20Denbury%20Gulf%20Coast%20Pipeline.pdf
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Significant improvements in upcoming Phast 9.1
• Liquid phase CO2 pipelines handled by Phast PIPEBREAK model
• Extended Phast 9.1 model PIPEBREAK-II with crucial
improvements for liquid CO2 pipelines
• Initial rapid depressurization modelling for dense liquid
• Modelling small holes (aperture ratio below 20%)
• Modelling of liquid densities (inventories)
Impact
• More accurate liquid pipeline releases  avoid workarounds
• Avoid underprediction of fluid inventories
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Phast PIPEBREAK-II: CO2PIPETRANS validation
• DNV-led JIP, tests at DNV Spadeadam in 2012/13
• Full validation to be published, including dispersion
• 200 m long pipe, 52 mm diam. P~100 bar, T ~3-14°C
• Extended model validates well for CO2PIPETRANS
• 8 releases from end of pipe, hole size: 10-50 mm
• Test 6: hole size 10 mm, 3.6% relative aperture
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Phast CO2 modelling: Further information
Knowledge Centre: https://myworkspace.dnv.com/knowledge-centre/phast-and-safeti
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Select publications on Phast CO2 modelling
• Modelling of discharge and atmospheric dispersion for carbon dioxide releases
(Journal of Loss Prevention, 2009)
• Modelling of discharge and atmospheric dispersion for carbon dioxide releases including
sensitivity analysis for wide range of scenarios (Energia Procedia, 2011)
• Phast validation of discharge and atmospheric dispersion for pressurised carbon dioxide
releases (Journal of Loss Prevention, 2014)
• Verification and validation of Phast consequence models for accidental releases of toxic or
flammable chemicals to the atmosphere (Journal of Loss Prevention, 2018)
• Model improvements and validation for buried CO2 pipeline ruptures
(Mary Kay O’Connor Safety & Risk Conference, October 2023)
• A comprehensive pipeline source term model for pressurized/flashing liquids in Phast/Safeti
(PIPEBREAK-II) (Global Congress on Process Safety, March 2024)
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KAMELEON FIREEX KFX®
dispersion modelling
CO2 releases to the atmosphere
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Atmospheric CO2 gas dispersion
Typical release of liquid or supercritical CO2
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CO2 dispersion in complex terrain
• Full-scale CO2 dispersion predicted by KFX™-CO2 .
• Multiphase CO2 dispersion from release of CO2 stored as liquid at 16 bar Release of 570t CO2
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Predicted 4 vol % CO2 iso-surface development after rupture of a pipe connection below CO2 storage tank
CO2 dispersion in complex terrain
Reliable CO2 dispersion simulation
technology, which accounts for effects of:
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•
•
•
CO2 thermodynamics
Geometry
Topography
Atmospheric conditions,
is a key to safe, full-scale CCS
Major full-scale CO2 accident scenario simulated with KFX™-CO2
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KFX™-CO2 Joint Industry Project (JIP)
• Improve modelling and validation of complex
thermodynamics processes for liquid releases
including
• Dry ice formation
• Deposition of solid particles in complex geometries
• Sublimation and dispersion of the resulting cloud
• Account for 3D time varying effects of terrain, geometry
and atmospheric conditions
 Provide a solid basis for improved CCS safety and
for finding cost-effective technical solutions for
design
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CO2 concentrations predicted by KFX™-CO2 through a
high-pressure CO2 release, including visualization of small,
solid CO2 particles in the gas flow
KFX validation for CO2
KFX vs. measurements
BP tests
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Shell tests
KFX-CO2 JIP: Findings so far and next steps
• Improved thermodynamic models predicting
source characteristics at expanded
conditions as input to multiphase dispersion
• Improved models for gas dispersion being
developed and tested focusing on:
• Able to predict formation of solid particles, including
sublimation
• Improved treatment of wind boundary conditions
and atmospheric turbulence for far-field dispersion
including effects of water vapour condensation
• 2-phase release of a mixture of vapour and solid
modelled using interconnected Eulerian-Lagrangian
model to describe behaviour of solid particles
• 3D terrain and geometry modelling with automatic
import of map data and CAD models for accurate
dispersion simulation
• Model for interaction of solid particles and surfaces
will be implemented
• Algorithms for automatic import and conversion of
topography data into appropriate CFD geometry
models
• Testing against full scale scenarios being developed
with customers
• Investigation of effects of vegetation using 3D
vegetation data
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Effects of vegetation on CO2 dispersion
• Vegetation has a huge capacity for storing and
slowing down spreading of leaked gas because
of:
• high drag
• low solid fraction
• Leaked (dense) gas such as CO2 can be hold
back in the forest making the lethal volume
close to leak point much larger.
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CO2 releases under water
Source term and dispersion modelling
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Under water CO2 release
• Offshore CO2 pipelines might be a major hazard.
• Pipeline failure  CO2 plume under water  CO2
cloud on the surface
• Understand
• behaviour of CO2 leaking from underwater highpressure pipelines
• impact of CO2 releases on the safety of shipping or
offshore infrastructure.
• Input to QRA
 Setting up safety guidelines for CO2 offshore pipelines
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Sea current
Dissolved
CO2
Coral
reef
Under water CO2 release – the questions to answer
How is the plume of the
release affected by a
current above the
release?
How much of the gas is
dissolved in the water
at real, large-scale
conditions?
At what release
rates/depth will bubbles
start reaching the
surface?
What concentration of
CO2 is recorded at the
surface above the
release?
How is the dynamics of
the bubble zone, and how
can the interface be
modelled in a best way?
What are the safety
distances on the surface
for personnel for different
subsea release rates?
What is the extent of
influence zones for
marine life for different
subsea releases?
What are the capabilities
to predict both the
subsea and atmospheric
CO2 plumes?
Spadeadam Testing Centre - UK
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Under water CO2 release
– Experimental set-up
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Under water CO2 release
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4 mm upward CO2 release - video
Under water CO2 release
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4mm downward CO2 release - video
SINTEF SURE + DNV KFX™ for under water CO2
release modelling
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DNV’s expertise in CCS
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Developing the first international CCS standards
DNV
RESEARCH/JOINT
INDUSTRY
PROJECT
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CO2RISKMAN – Guidance on CCS CO2 Safety and Environment Major Accident Hazard Risk Management
CO2 PIPETRANS – Guidance on transportation component of CCS projects
CO2SafeArrest – Guidance on the efficient design of CO2 pipelines
CO2QUALSTORE – Guidance for the selection and qualification of CO2 storage sites
CO2 WELLS – Guidance on the risk management of existing wells at CO2 storage sites
CO2 CAPTURE – Guidance on procedure for capture technology qualification
HiPerCap – Development of novel Capture technologies
ECO2 – Best environmental practice for offshore CO2 injection
DNV
RECOMMENDED
PRACTICE
DNV-RP-J201
Qualification procedures for carbon
dioxide capture technology
DNV-RP-F104
Design and operation of carbon dioxide
pipelines
DNV-RP-J203
Geological storage of carbon dioxide
INTERNATIONAL
STANDARD
ISO 27919-1
Carbon dioxide capture – Performance
evaluation methods for post-combustion
CO2 capture integrated with a power
plant
ISO 27913
Carbon dioxide capture, transportation
and geological storage – Pipeline
transportation system
ISO 27914
Carbon dioxide capture, transportation
and geological storage – Geological
storage
DNV-SE-0160
DNV-ST-F101
Technology qualification management
and verification
Submarine pipeline systems
DNV-SE-0473: Certification of sites and
projects for geological storage of CO2
DNV-SE-0617: Qualification management
for geological storage of CO2
DNV FRAMEWORKS
FOR ASSURANCE
SERVICES
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Helping scale CCS: 200+ projects in past 10 years
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CAPTURE
TRANSPORT
STORAGE
• Fossil power plants
• Natural gas CO2 reduction
• Other industrial processes
• Pipelines
• Ships
• Depleted oil or gas reservoirs
• Saline aquifers
• Enhanced oil recovery (EOR)
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Cost estimations
Introduction of new technologies
Technology review and benchmarking
Up-scaling risk assessment
HSE risk assessment
Accidental release and dispersion
Value of avoided CO2
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Corrosion
Material selection and structural design
Flow assurance and operational issues
Accidental release and dispersion
Concept design for CO2 ships
Requalification of infrastructure
Verification of storage sites
Permanence of storage
Risk management
Monitoring and verification
Public concern
Transfer of responsibility
DNV’s ongoing activities
• SUB-CO2 Phase 3
• Skylark
• CO2SafePipe
• KFX-CO2
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Summary
• R&D pivotal to understand
underwater and atmospheric CO2
releases and dispersion and its
associated risks
• Consequence modelling tools: Phast
and KFX developed to handle key
physical phenomena such as:
• Sublimation
• Solid deposition
• Craters
• Time-varying releases
• Topography
• Vegetation
• JIP between DNV and partners
contribute to developing models for
our tools and setting up guidelines
for safe CCS
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Image provided by the Global CCS Institute
Thank you
digital@dnv.com
www.dnv.com
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