Wärtsilä Ship Design for Aframax
Transcript of Wärtsilä Ship Design for Aframax
EFFICIENT AFRAMAX DESIGN PROVIDING SOLUTIONS FOR EMISSIONS LEGISLATION (SOX and NOX)
At Wärtsilä, we are passionate about
optimising lifecycle value by offering
precisely what each of our customers need.
We can deliver on this promise because
we provide the only true total offering of
marine products, integrated solutions and
services in the industry – worldwide. We
help our customers find the shorter route
to robust growth and bigger profits through
operational efficiency, environmental
excellence, fuel flexibility and services. Even
though this brochure is just a beginning
to learn why Wärtsilä nowadays powers
one in every three ships worldwide, it still
demonstrates how we are able to customise
our comprehensive offering in order to give
customers a crucial competitive edge. What
can we do for you?
• A single decked, single screw motor ship with
machinery and accommodation located aft
• Double bottom and double shell protection
along cargo area
• Compliant with Common Structural Rules
(CSR) for double hull tankers
• The centre section to be subdivided into
twelve (12) cargo tanks by means of
transverse bulkheads and one longitudinal
bulkhead at the centre line. Slop tanks and
cargo drain tank to be arranged aft of cargo
tanks
• Clean design – HFO tanks in engine room
arranged with cofferdams against outer shell
• Unrestricted ocean services and terminals
compatible with vessel’s dimensions
TANKER FOR CRUDE OIL AND DARK PETROLEUM PRODUCTS
WSD AFRAMAXMAIN DATALength over all ..................................253.20 mDeadweight ................................. 117,500 dwtSpeed ............................................ 14.8 knotsOperation range ............................ “Worldwide”Main engine .................................Wärtsilä X62
RESISTANCE AND PROPULSIONDuring design stage hull shapes have been
generated and carefully tested by means of
RANS CFD computations.
The purpose has been to minimise hull
resistance and maximise propulsive efficiency of
the vessel keeping constrains of deadweight and
cargo capacity to the upper limit.
During optimisation stage wave profiles,
pressure distribution and flow lines along the
hull have been carefully analysed. Necessary
modifications have been done showing
sufficient improvement in the forward and aft
parts of the hull.
Finally cylindrical bow design showed
improved performance for variable operational
draughts and also during rough weather
conditions still having high deadweight and
cargo capacity kept.
Propulsion of the vessel has been
optimised by the adaptation of the modern
high performance electronically-controlled
2-stroke long-stroke / low-speed Wärtsilä X62
engine. The new engine offers high propulsion
efficiency in a unique combination of low
engine revolutions and an engine design with
a minimum physical width. This benefit results
in a slimmer aft body design leading to further
propulsion efficiency improvements. When
comparing the new Wärtsilä X62 to currently
available main engine options, a gain of
approximately 7% in efficiency can be achieved.
Thanks to the optimised engine parameters,
the required propulsion power for the same
vessel speed for the specific vessel can
be achieved with one cylinder less (6 cyl)
compared to previous generation main
engine options. With a propeller diameter of
7600 mm, including a sea margin of 15%
and an engine margin of 10%, Power (Pb) of
14,400 kW at 92 rpm is required.
A 7 cylinder is a solution for even higher
efficiency due to the lower rpm and higher de-
rating potential that can be achieved. Power
(Pb) of 14,150 kW at 83 rpm is required with
a propeller diameter of 7900 mm, including
a sea margin of 15% and an engine margin
of 10%.
The achieved EEDI value is below the
requirements of Phase 1 (Jan 2015–Dec
2019). Further reduction can be achieved with
waste heat recovery, power take-off devices.
During optimisation stage vessel’s hull form was considerably improved providing lower resistance with higher propulsion efficiency together with the increased deadweight and cargo capacity.
Aframax tanker (previous generation
main engine)
Aframax tanker (Wärtsilä X62 main engine)
Propeller diameter 7200mm 7600mm 7900mm
Number of cylinders for main engine 7 cylinders 6 cylinders 7 cylinders
Efficiency gain due to larger propeller Reference ~ 4% ~ 5%
Efficiency gain due to higher engine internal efficiency Reference ~ 1% ~ 1%
Efficiency gain due to de-rating potential Reference Equal to reference ~ 1%
Total efficiency gain ~ 5% ~ 7%
Daily fuel consumption at CSR (approx MT/day) 53.5 50.9 49.5CSR = Continuous Service Rating / LCV of MDO = 42,700kJ/kg
Wärtsilä X62 – High performance 2-stroke main engine – Electronically-controlled common-rail – Extra long stroke – Low rpm.
SOLUTIONS FOR NOX AND SOX EMISSIONSIn order to achieve compliance with both the
IMO Tier III NOX standards and the requirements
for SOX control, aftertreatment solutions such as
SCR and Scrubber have been selected. In the
main engine the SCR unit is placed before the
turbocharger turbine and the Scrubber unit is
placed on the funnel. The equipment are tuned
together with the main and auxiliary engines for
operation in the complete load range.
AFRAMAX CASE STUDY – OPERATION IN ECAA case is shown of an Aframax tanker with a
route between Galveston (US) to Rotterdam
(NL). Assuming the North America and the
European ECA`s, the percentage of the time
spend in ECA`s per roundtrip corresponds to
approximately 35% including harbour time.
By the installation and operation of scrubbers,
savings to the order of 7% can be achieved
per roundtrip. In the case of an increased time
spend in ECA savings will be even higher. Fuel
costs include the operation of the auxiliary
engines but the consumption of auxiliary boilers
during port stay has not been taken into account.
The alternative with SCR is Tier III compliant.
ASSUMPTIONSHFO price: .....................................650 USD/tonneMGO price: ....................................975 USD/tonneUrea price: .....................................240 USD/tonneCaustic soda price: .........................235 USD/tonne
SCR (Selective Catalyst Reactor) Scrubber (Funnel positioned)
Oper
atin
g tim
e pe
r rou
ndtr
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)
50
45
40
35
30
25
20
15
10
5
0Harbour 12.5 knots
(reduced speed)14.8 knots(ballast)
14.8 knots(loaded)
Outside ECA
Inside ECA
Cons
umab
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osts
per
roun
dtrip
(kUS
D) 1000
800
600
400
200
0Wärtsilä 7X62
(Tier II)Wärtsilä 7X62
(SCR & scrubber, Tier III)
100.0%93.2%
NaOHUreaMGOHFO
1200
Operating profile per roundtrip (Galveston – Rotterdam).
Comparison of consumable costs per roundtrip of the different alternatives.
Daily fuel consumption vs vessel speed Design Draught / LCV-42,700kJ/kg / Delta Tuning (Part load)
10.815.0
20.0
25.929.0
31.7
36.3
40.6
45.8
52.4
0.0
10.0
20.0
30.0
40.0
50.0
60.0
8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0Vessel speed (knots)
Fuel
con
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T/da
y)
WÄRTSILÄ EQUIPMENT • Main engine (Wärtsilä X62 –
electronically-controlled common-rail) • Auxiliary engines/generators
(Wärtsilä genset 20) • Integrated scrubber
(Main engine+Auxiliary engines+Auxiliary boilers)
• Selective catalyst reactors • Automation • Fixed pitch propeller, seals and
bearings • Ballast water treatment • Oily water separator • Inert gas systems
WÄRTSILÄ® is a registered trademark. Copyright © 2012 Wärtsilä Corporation.
WARTSILA.COM
MAIN DIMENSIONSLength over all, approx. .........................253.20 mLength between PP ...............................244.60 mBreadth moulded ....................................44.00 mDepth moulded, approx. ..........................21.30 mDesign draught .......................................13.60 mScantling draught ....................................15.20 mGross tonnage, approx. .........................65,000 GTDeadweight, D = 15.20 m ................ 117,500 dwt
SPEED
Speed, d = 13.6 m, approx. ..................14.8 knotsCruising range ....................................14,700 nm
CAPACITIES
Cargo tanks, approx. ..........................134,250 m³Slop tanks, approx. ..................................3020 m³Ballast water tanks, approx. ..................39,600 m³HFO, storage, serv., approx. .....................3115 m³MDO, approx. ...........................................520 m³Lub. Oil, approx. ........................................250 m³ME cylinder oil, approx. ...............................50 m³Fresh water tanks, approx. .......................2000 m³Urea, approx. ............................................310 m³Caustic soda, approx. ................................370 m³
PROPULSION PLANT
• 1x2-stroke Wärtsilä X62 § 6 cyl CMCR 14 400 kW at 92 rpm FP-propeller, Æ 7 600 mm or
• § 7 cyl CMCR 14 150 kW at 83 rpm FP-propeller, Æ 7 900 mm
DECK’S EQUIPMENT
• One Free-fall motor lifesaving boat for 40 persons• Four inflatable rafts for each 20 persons• One inflatable raft for 6 persons• One Rescue boat
SHIP EQUIPMENT
• One balanced semi spade rudder• One el.-hydraulic steering gear
DECK’S MACHINERY
• Two separate combined windlass/mooring winches, main deck fwd.
• Two mooring winches, main deck, fwd area• Two mooring winches, main deck forward of
accommodation block• Three mooring winches, main deck aft.
AUXILIARY ENGINE PLANT• Three auxiliary diesel generator sets• Wärtsilä 875W6L20, 875 kWe, 900 rpm• One emergency / harbour generator set
E-PLANTPower .....................................3 AC, 440 V, 60 Hz
ACCOMMODATION• 32 persons fully air-conditioned
CLASSIFICATION• DNV Tanker for Oil, ESP, CSR
PLUS, NAUTICUS (Newbuilding), BIS, TMON, E0, NAUT-AW, COAT-1, SPM, OPP-F, CCO, VCS-2, CLEAN
EMISSIONS• Compliance CO2 – EEDI value 3.59 (7 cyl engine)
(Below Phase 1, Jan 2015–Dec 2019)• Compliance NOX – IMO Tier III (SCR)• Compliance SOX – 0.1% sulphur limit (Scrubber)
(IMO / USA / Europe – SOX legislation) or low sulphur fuel/distillates
SP
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08.
2012
Boc
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