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Classification: Statoil internal
The Zero Continuous Flaring Technology.Thormod Hope, Vice president Statoil EPN ONS Brage.
Classification: Statoil internal
Facts.• The Norwegian Continental Shelf
(NCS) is the most energy efficient petroleum region in the world, producing oil and gas with 60% less energy than the world average. Limited flaring is a significant reason.
• Flaring currently accounts for about 10 % of Statoil’s carbon emissions. In 1995 the figure was about 20% (NDP).
• Norway’s special carbon tax has been an important carrot in reducing the amount of gas flared.
Classification: Statoil internal
History.Using Gullfaks C as a case Statoil experienced that:
Too much gas was burned during a normal day.
Too much time were spent to detect leaking flare valves and doing maintenance on leaking valves.
CO2 tax at about $ 8 million from flaring per year could be reduced.
From an environmental point of view, flaring was one of the emissions that could be reduced.
Classification: Statoil internal
In 1990 the Norwegian government introduced the CO2 tax.
CO2 tax was calculated based on the amount gas emitted to the flare.
Statoil through its Gullfaks field developed in 1992 a system eliminating continuous flaring by recycling the flare gas.
A flare ignition system was developed to ignite the flare in emergency situations.
14th of November 1994 Statoil’s Gullfaks A and Gullfaks C platforms operated the first zero normal flare system.
History
Classification: Statoil internal
New flare practice on Gullfaks oil field
•One production mode - Two flare modes
Open and ignited flare Closed flare system
Classification: Statoil internal
Illustration of continuous and non-continuous flaring
Continuous flaring:
Non-continuous flaring gas:
time
• Purge gas.
• Leak gas from valves. • Vast gas.• Equipment blow-down.
• Emergency depressurization.• Compressor trip.• Etc.
Classification: Statoil internal
Estimates of reduced flaring
•Total flaring 2005 for Gullfaks C: 25 656 Sm3/day•Continuous basic load: App. 50 000 Sm3/day•Estimated total flare load: App. 75 000 Sm3/day
•Estimated reduction for Gullfaks C in 2005: 60 – 70%.
Average reduction in yearly flaring due to the “no-flare” technology is approximately 50 % on Gullfaks during normal operation.
Classification: Statoil internal
Basic elements in the new flare system
1. High integrity flare opening valve (FOV)
2. Flare gas recovery system
3. Flare ignition system
4. High quality safety system
Classification: Statoil internal
Basic elements in the new flare system
To the flare stack withignitionsystem
XV
HP K.O. Drum
Bursting Disc
Sources
PTHH
PTHH
LO LO
FOV
Flare gas recovery system
Classification: Statoil internal Flare Gas Recovery
Fast Opening Valve (FOV) layout.
To flare
Tie-in 1
Tie-in 2 Manual valve
Bursting disc
FOV
Flare K.O. drum
Classification: Statoil internal
Flare gas recovery equipment
•Several options exists.•Cost effective solution is based
on finding the correct tie-in. •Typical recovery packages are:
– Cross over line
– Ejector skid
– Blower skid
– Screw compressor skid
– Liquid ring compressor skid
Ejector
The ejector used at Gullfaks.
Classification: Statoil internal
Flare Ignition System
An long rang ignition pellet is launch when the flare need to be ignited.
Long-range ignition pellet
The ignition pellet is launched through a guide pipe and ignite when the pellet emerge from the guide pipe.
Ignition unit
Classification: Statoil internal
Zero continuous flare system - 15 years after.
Most new platforms at the Norwegian Continental Shelf have installed the system which has become the new design standard.
The technology led to a revised international flare standard API 521.
The flares on Gullfaks A and C in the North Sea were extinguished by Statoil 15 years ago, cutting carbon emissions by 1.5 million tones. That equals the volume released during one year by 625,000 cars.
Since the technology was adopted on Gullfaks, it has been used in full or in part on about 30 Norwegian offshore installations as well as off Azerbaijan, the UK, Angola and elsewhere.
BP FPSO ”Greater Plutonio” northwest of Angola.
Classification: Statoil internal
• The flare has always been a symbol for stable production.
Now a flameless flaremay be a symbol for stable and clean production.
Statoil Oseberg Field
