Emission Control Technology for Marine Applications

IMO MARPOL VI: Stage TIER III

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Tier I Tier II Tier III

RPM

NO

X g/

kWh

From TIER I to Tier II engine modifications are sufficient

From TIER II to Tier III engine modifications are no longer sufficient and

emission technology is required

The challenge is NOX reduction: the most

obvious solution is SCR technology

SCR catalystEngine

Urea Pump

Urea Doser

Urea tank

SCR Schematic Layout

Control Unit

SCR Pros and Cons

Emission target TIER III can be achieved for both TIER 1 and TIER II engines

Can be used with diesel containing sulphur (up to 2000 PPM*)

Exhaust geometry less flexible

Engine can be optimized for fuel consumption

Extra tank

Extra technical complexity

SCR technology was introduced >10 years ago in the HD market.

Extra cost (investment)

Over 1 500 000 installations are operational today

Extra cost of ownership

* Sulphur impact on system size

Ceramic substrates

Possible catalyst chapes

Metal substrates

Race track

Rectangle

RingRound

Oval

Square

Round

Oval

Square

Oval ring

Race track ring

Validation programs SCR(F) on two ships

Barge

This is considered as a normal application

Engine: Scania V8 16 liter 450 kW

Police Patrol ship

Considered as a worst case scenario

Engine : 2 x MTU V2000-01 600 kW

The Barge

The Barge

DOC SCR(F)

The barge

The silencer

The SCRF

The patrol ship

The patrol ship

The patrol ship

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SCR for Superyachts

Superyachts have access to good quality fuel

(European and American ports / marinas deliver road fuel or low sulphur fuel maximum 1000 PPM )

Facts

Superyachts use mainly high speed diesel engines

Annual operational hours are low150 -200 hours for privately owned vessels

500 hours for charter vessels

The average load profile is low

Challenge for superyachts

Integration of the SCR into the silencer• Space for SCR catalyst• Urea mixing – Gamma over the catalyst • Pressure drop• Silencing capacities• Maintenance and service

Model from DISCOM BV Netherlands

Typical exhaust for superyacht

Dry exhaust bypass

Wet exhaust(venturi)

Examples for MTU 2880 kW – SCR

Silencer for Superyacht with MTU 2880 kW.• Catalyst volume required +/- 422 dm³• Available volume in silencer 5422 dm³ • Less then 8 % of silencer volume• Expected pressure drop over the SCR catalyst 14 mBar

Model from DISCOM BV Netherlands

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SCR sizing versus fuel quality

Parameters affecting durability

Sulphur from fuel and lubrication oil- Formation of ammonium bisulphate (NH4SO4) – reversible- Clogging by soot and metal sulphates - reversible/irreversible

Phosphorous from lubrication oil- Phosphorous depositing in the catalyst pores – irreversible

Alkali metals- Na and K react with active sites on the surface – irreversible

Temperature- Sintering of the catalyst carrier – irreversible

Test results prove

Regulated emissions are not affected with sulphur levelsup to at least 350 ppm in the fuel with vanadium SCRCatalyst (tested for 4200 hours) (testcycle E3, ETC, ESC).

Testing with 1200 ppm S fuel shows that NOx conversion is affected when long periods of low temperatures occur.

Testing reveals good sulphur tolerance of the vanadium SCR catalyst as activity is fully recovered at increased temperature (350°C).

Urea dosing strategy must be adjusted accordingly.

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Urea dosing & NOx measurement for ships

Urea dosers

Injection section

Urea pressure rail

& Urea return rail

Nox sampling

Control cabinet - multi engine

Conclusions

Superyachts can be equipped with compact SCR systems that are resistant to the fuel used in this market.

By using metal substrates, a high degree of freedom in design is possible and can be combined with low pressure drops.

SCR systems will be effective between 20 % and 100% of engine load.

Last minute roll-out / introduction / implementation will lead to systems that are neither validated nor optimized for cost.

There are no other drawbacks for the technology other than economical drawbacks (space, investment, cost of ownership).

Thank you for your attention