Post on 01-May-2018
K E I T H S P E N C E
HEALTH AND SAFETY RISKS OF CARBON CAPTURE,
TRANSPORT & STORAGE
WHAT IS HEALTH AND SAFETY?
• Occupational safety and health
• Primarily covers the management of personal health & safety i.e. the safety, health & welfare of people engaged in work or employment
• Good management systems also address process safety issues
• Process safety
• Focuses at more of a system level on preventing fires, explosions & accidental chemical releases in chemical process facilities or other facilities dealing with hazardous materials
• Prevention of major accident events
• A major accident event (MAE) is an event connected with a facility, including a natural event, having the potential to cause multiple fatalities of persons at or near the facility
WHY HEALTH & SAFETY IS IMPORTANT FOR CCS
• Protection human health and safety
• Maintaining “license to operate” – increase
stakeholder/community confidence that CCS is reliable & safe
• Facilitating cost-effective, timely deployment – safety
promotes quality outcomes
• Protection of ecosystems
• Protection of underground sources of drinking water and other
natural resources
Transport
20%
Industry
26%
Buildings
8%
Other
6%
Agriculture
1%
Power
39% CCS is the only option available
to reduce direct emissions from
industrial processes at the large
scale needed in the longer
term.
CCS should play a key role in
curbing CO2 emission from fossil
fuel-based power generation,
potentially reducing the overall
cost of power decarbonisation
by around US$2 trillion by 2050.
Without CCS, reducing CO2 emissions through 2050 in a 2°C world is highly unlikely in industry and at best very expensive in power
(Source: IEA Energy Technology Perspectives, 2012,2014)
CCS PROCESS
Source: CO2CRC
Capture
Transport Storage
• Health and safety must be assessed across all elements of the
CCS process
• also over the project lifecycle from research, planning, design &
construction, operation & maintenance, decommissioning, long
term monitoring & stewardship
RISK MANAGEMENT CYCLE
Identify major
accident
hazards
Risk assessment
Identify key risk
treatment
measures
Reduce the
risks to
acceptable
level
Set
performance
requirements
Performance
assurance &
verification
Review &
improve
process
MAJOR ACCIDENT HAZARDS
• Identification of hazards at all stages of the CCS process
CO2 gathering
& compression
CO2 capture
from diverse emitters
CO2 transport CO2 storage
Integration hazards• Impact of process upsets
• Interface between different operators
• Impact of different organisational cultures
• Impact of different commercial priorities
• Emergency response
• Operating pressure
• CO2 gathering
networks
• Impact of impurities
in CO2 stream
• Supercritical CO2
• Impact of topography
• Impact of distance & time
• Heavily populated areas
• Variability of CO2 stream spec.
• Pipeline corrosion
• Release of CO2 through
pipeline rupture
• Release of CO2 from well failure
• Leakage into aquifers
• Drilling hazards
• Long injection well life
• Multiple land/resource use hazards
• Encroachment of population
post-closure
• Stewardship post closure
• Capture technology
• Impact on population
• BLEVE
• Water use
RISK RANKING TOOL
PeopleSlight injury or health effect
Minor injury or health effect
Major injury or health effect
Permanent disability of fatality
Multiple fatalities
Assets Slight damage Minor damage Moderate damage Major damage Massive damage
Economic 1% of budget 5% of budget 5-10% of budget>10% of budget
>30% of budget
Environment Slight effect Minor effect Moderate effect Major effect Massive effect
Reputation Slight impact Minor impact Moderate impact Major impact Massive impact
Probability Frequency Insignificant Negligible Moderate Extensive Significant
>95%Has happened more than once per year at the location
Almost certain
>65%Has happened at the location or more than once per year in the orgnisation
Likely
>35%Has happened in the organisation or more than once per year in industry
Possible
<35% Heard of in the industry Unlikely
<5% Never heard of in Industry Rare
Severe Tolerability to be endorsed by management - Immediate action required
High Manage to ALARP
Medium Management action required
Low Monitor and manage by routine procedures
Very Low Manage by routine procedures
Like
liho
od
Consequence
SEVERE
V. LOW
LOW
HIGH
MEDIUM
• Risk - combination of Likelihood &
Consequence
• Risks are compared using the risk
matrix – consequence is not just
about safety
• Effectiveness of
mitigations can
also be compared
• Severe/High risks
• mitigate to ALARP
• Take immediate
action
IS CO2 HAZARDOUS?
• Everyday substance in the air we breathe, in drinks etc
• Properties:
• Inflammable, non-toxic, heavier than air
• Uses – fire extinguishers, EOR, food & drink preparation, plant
growth stimulation humane killer many other uses
• But it is hazardous
• dangerous to humans in high concentrations (Immediate Danger
To Life & Health, IDLH, level is 4%)
• reduction in oxygen in breathing air
• effect on other CO2 stream components
• low temperature during rapid decompression
• corrosive effect on metal
MAJOR ACCIDENT EVENTS - CO2
• Lake Nyos, Cameroon 1986
• Nyos is a deep lake high on the flank of an inactive volcano.
• A pocket of magma lies beneath the lake and leaks CO2 into the water, changing it into carbonic acid.
• On 21 August 1986, possibly as the result of a landslide, Lake Nyossuddenly emitted a large cloud of CO2
(estimated 1,600 kT released) which rose at nearly 100 km/h
• The cloud spilled over the northern lip of the lake into adjacent valleys displacing the air and suffocating 1,746 people & 3,500 livestock within 25 km of the lake.
MAJOR ACCIDENT EVENTS - CO2
• Nagylengyel, Hungary 1998
• Naturally-occurring CO2 and H2S was injected into the Nagylengyel oil field as part of an Enhanced Oil Recovery project.
• The incident occurred on well NIT 1079 on 13 November 1998. Routine work was underway to replace a blowout preventer with a Christmas Tree well-head completion. It is likely that the work dislodged a packer seal, allowing CO2 to escape through the well annulus, leading loss of control. The well was controlled after 60 hours.
• No one was injured but 5,000 inhabitants from three adjacent villages, were evacuated.
Outbreak of CO2 escape
CO2 storage facilityAssume ~30mpta onshore CO2 injection300 injection wells, 20 years of injectionRelease frequency – HC gas injector well is ~3 x 10-5/well year
Likelihood of CO2 release over well injection life ~18%
MAJOR ACCIDENT EVENTS - CO2
• Worms, Germany 1988• On the 21 November 1988 there was a catastrophic failure of a vessel
containing liquid CO2 (30 tonnes) at a citrus facility.• The vessel was over-pressured, leading to loss of containment. • A CO2 Boiling Liquid Expanding Vapor Explosion (BLEVE) occurred • The force of the explosion propelled the majority of the vessel into the
Rhine river, ca 300 m away.
• There were three fatalities, eight employees were hospitalised with serious injuries, three months’ lost production and 20 million dollars’ worth of property damage.
• Monchengladbach 2008• 15 tonnes of CO2 accidentally released from a fire extinguishing system
• 107 people intoxicated• 19 people hospitalized• several fell unconscious & would have died if not rescue
RISK ASSESSMENT
• What could happen?
• Consequence - How much? Duration? How far? How bad?
How many people affected?
• Likelihood - how often?
• What is an acceptable level of risk?
RISK RELATED DECISION SUPPORT FRAMEWORK (OIL AND GAS UK, 2014)
Drilling wells
CO2 storage
wells
CO2 TRANSPORT MAJOR ACCIDENT HAZARD – ASSESSMENT EXAMPLE
• CO2 transport is not new - today, >40 Mtpa of CO2 is safely
transported through over 5,800 km of pipeline
• The scale of future infrastructure & its proximity to populated
areas introduce a risk exposure
• What could happen?
• Accidental discharge & dispersion of concentrated CO2
• What causes?
• Corrosion from uptake of humidity
• Over-pressuring pipeline
• Material compatibility (elastomers, polymers)
• Consequence
How much, what duration?
• Brittle & ductile fracture: in-service ductile fractures have propagated up to 300m in natural gas pipelines
• CO2 is to be transported in dense phase (~400x density of CO2 in air), in big diameter pipelines (e.g. 48”) so CO2 “inventory” is significantly increased
Fracture in natural
gas pipeline
CO2 TRANSPORT MAJOR ACCIDENT HAZARD – ASSESSMENT EXAMPLE
• How far?
• CO2 is heavier than air and can accumulate in low topographic points
• Dispersion modelling along pipeline route to estimate distances & concentrations
• How bad? How many people?
• CO2 is dangerous to humans in very high concentrations - IDLH is 4%
• Likelihood?
• has occurred known in the oil and gas industry. But scale and phase of CO2 transport is new.
• What is an acceptable level of risk?
Dispersion modelling& dose contouring
(UK HSE)
Pipeline fracture arrestor
WHAT IS AN ACCEPTABLE LEVEL OF RISK?AS LOW AS REASONABLY PRACTICABLE (ALARP)
• For risk to be ALARP, it must be possible to demonstrate that the cost
involved in reducing the risk further would be grossly disproportionate to
the benefit gained
Unacceptable
Broadly
acceptable
or negligible
Tolerable or
ALARP
Risk not justifiedexcept in exceptionalcircumstances
Tolerable only if risk
reduction is impracticableor if cost grossly
disproportionate to thebenefit gained
No need for detailed effort to demonstrate ALARP
Inc
rea
sin
g in
div
idu
al ri
sk &
soc
ieta
l c
on
ce
rn
HIERARCHY OF CONTROLS
Elimination
Substitution
Engineering
Controls
PPE
Administrative
Controls
Most
effective
Least
effective
Physically eliminate
the hazard
Replace hazard with
processes/methods with
lower risk
Isolate people from
the hazard through
engineering design
Change the way people work –
training, competency, procedures,
permits, maintenance, ER
Protect workers with
personal protective equipment
CO2 TRANSPORT MAJOR ACCIDENT HAZARD EXAMPLE – REDUCE THE RISK
• Fracture of pipelines can be controlled by:
• control of steel toughness to prevent brittle fracture and to control ductile fracture.
• mechanical collar devices (fracture arrestors) that surround the pipe are employed along the pipelines to arrest a propagating fracture
• Consequence of release can be mitigated by route selection away from populated areas & areas of high risk identified by dispersion modelling
• In heavily populated areas, transport CO2
as low pressure, gaseous phase to reduce inventory
Pipeline fracture arrestor
BOW-TIE TECHNIQUE FORHAZARD & RISK MANAGEMENT
HazardThreat
Threat
Threat
Prevention
barriersConsequence
Consequence
Consequence
Escalation
Barriers
Event/
Loss of
control
Prevention: reduce
the likelihood of
the event
Control & recovery:
limit & mitigate
consequences
Event
THE SWISS CHEESE MODEL
• Accidents are rarely attributed to a single cause/failure – there
are usually many contributing factors
• While many layers of defense lie between hazards and
accidents, there are flaws in each layer that, if aligned, can
allow the accident to occur
Latent conditions create breaches in
barriers - poor design, procedures,
decisions, training
CONCLUSIONS
• Studies show no major show stoppers associated with the CCS process
• comparable risk versus distances for gaseous CO2 and natural gas
• Operators have the tools to prevent major incidents so far as is reasonably practicable
• Major hazard laws and regulations require this
• While it is tempting to say that there are many similarities with Oil and Gas, there are many aspects of CCS that are unique and sometimes subtly different (e.g. scale versus impact on basin hydrogeology)
• Piloting CCS technologies & practices at smaller (but industrial) scale mitigates the implementation risks & provides an opportunity to learn while building vital stakeholder/community confidence that CCS is reliable & safe