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MAINTENANCE & TECH SUPPORT May 16, 2011 Emissions from offshore drilling operations
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Page 1: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

MAINTENANCE & TECH SUPPORTMay 16, 2011

Emissionsfrom offshore drilling operations

Page 2: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Synopsis

Today, offshore drilling is a power intensive industry and as such the large drilling platforms potentially emit in excess of 25,000 tonnes of CO2/year. EPA’s threshold for a “major” source of CO2equivalent emissions.

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Page 3: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

OperationsOur challenge is in how we operate, and what BACT can be introduced given the conflicting demands of diesel efficiency and safe, black out free operations. Our drilling operations require power at all times and spinning redundancy. However, the best efficiency comes when running at a steady 85% load.

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Normal load 1,200 kW (25%)

Peak loads 2,600 (55%)

55% * 2 = 110%, if only one engine was running; BLACKOUT

Page 4: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

0

200

400

600

800

1000

1200

1400

1600

1800

2000

8:36 9:06 9:36 10:06 10:36 11:06 11:36 12:06

Engine 1

Engine 4

Max load 1850 kW. (39%)

Min Load 1100 kW. (23%)

However, we’re not always tripping pipe and the engines can be loadedup better. Power management needsexamining

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Page 5: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Many emissions reduction technologies are in development; however, these are not commercially available yet for large marine engines. SCR’s are available but are impractical for an offshore drilling rig

Emission Reduction

Technologies

Exhaust Gas RecirculationIgnition timing retardationDerating of enginesDirect water injectionEmulsified fuel useHumid air motor/water mistNOx Scrubber/absorber technologyReplacement of enginesSelective Catalytic Reduction (SCR)Good Combustion Practice

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Page 6: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Uninformed Assumptions

Initially, offshore industry was being pushed into the use of SCR’s by governing agencies.We studied the feasibility of operating an SCR system offshore and identifiedthe pitfalls in the operation and logistics. For offshore drilling, SCR’s are a non-starter…

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Page 7: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

First StepsTo be able to reduce emissions, we need to ensure that all quick fixes and simple steps have been taken to reduce emissions before moving on to major overhauls and fixes. To this end, we have devised a system that we have called DEWT. Diesel Emissions with Turbochargers.

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Page 8: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Basic Requirements

NOx ρ – derived from NOx ppm concentration

Load – Generator load in kW.

Exhaust Flow – Air flow + fuel flow

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Page 9: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Air FlowFlow of any description is the most difficult variable that is needed to measure; for this reason, we look at what is normally measured.

Pressure. (Charge air & E.R. pressure)

Temperature. (Temperatures for the gas through the combustion process)

Turbocharger RPM.

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Page 10: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Air FlowFlow of any description is the most difficult variable that is needed to measure; for this reason, we look at what is normally measured.

Pressure. (Charge air & E.R. pressure)

Temperature. (Temperatures for the gas through the combustion process)

Turbocharger RPM.

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Page 11: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Air FlowWe are able to calculate the NOx reading using temperature and pressure data, measured with a time stamp to generated load

Exhaust Gas FlowThe exhaust flow is the combination of the air flow and fuel flow. For a diesel engine, that’s approximately the ratio of 50:1.

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y = 0.177x3 - 1.537x2 + 6.174x - 4.105

02

46

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0,0 1,0 2,0 3,0 4,0

Air F

low M

³/sec

Pressure Ratio

Air flow formula

Air flow

Poly. (Air flow)

Charge Air Pressure bar

Charge Air Temp ºC

Turbocharger RPM (A & B) RPM

Exhaust Temp after blower(s) where exhaust sample's taken. ºC

Engine air inlet pressure mbar

Engine air inlet temperature ºC

Engine Air inlet relative humidity %

Generator Load kW

Emissions concentration ppm

Test Bed fuel Consumption g/kW·h

Page 12: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Data Collection & Actions

The DEWT system is designed to be used twice daily, over an average of 60 minutes. This value is logged in our daily machinery report along with the other, normal engine parameters. From this, our maintenance system will raise a flag to inspect the engine if the NOx level is rising.

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Page 13: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Actions

Once the DEWT system indicates a rise in emissions, the maintenance system instigates a job to investigate the engine combustion. The investigation identifies the emissions deviation and fixes it. Essentially this moves engine maintenance to CBM, the condition being the emissions value.

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Page 14: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Today

Today, we have a rig with a permit that’s currently open for public comment. This permit includes fully trialing DEWT whilst drilling east of 87½°Longitude.

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Page 15: Emissions from offshore drilling operations - IADC Robertson.pdf · Emissions from offshore drilling operations. Synopsis Today, ... Engine air inlet pressure mbar Engine air inlet

Questions?

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