Emission Control Technology for Marine Applications

IMO MARPOL VI: Stage TIER III 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 NO X reduction: the most obvious solution is SCR technology

SCR catalyst Engine 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 installations are operational today Extra cost of ownership * Sulphur impact on system size

Ceramic substrates Possible catalyst chapes Metal substrates Race track Rectangle Ring Round 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 V kW

The Barge

DOC SCR(F)

The barge The silencer The SCRF

The patrol ship

13 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 low 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

17 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 levels up to at least 350 ppm in the fuel with vanadium SCR Catalyst (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.

20 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).

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