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Dual-fuel Low-Speed Main Engine for Newbuilds and Retrofit
Dual-fuel Low-Speed Main Engine for Newbuilds and Retrofit
Rudolf Wettstein, Application Development
Ship Power 2-stroke, Wärtsilä Switzerland Ltd
Ship Management KonferenzSeptember 25, 2014, HamburgShip Management Konferenz
September 25, 2014, Hamburg
Content
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Introduction
Concept & Design details
Emission levels
Safety aspects
Fuel gas handling system
2sDF engine portfolio
References
Summary
3 pillars required for the success of LNG as fuel
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Environment sustainability
Economics Safety & reliability
The driving forces behind the “LNG as fuel” trend are environmental and economical considerations
The development path for gas powered Marine Engines1972 – launching 7RNMD90Low-Pressure DF Engine for 29,000 m3 LNGC, ‘MV Venator’ Moss Yard, Norway
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1986 – testing High-Pressure DF Engine 6RTA84 at IHI, Japan
1995 – Low-Pressure Dual-Fuel EngineBreak through in marine segment
2013 – Low-Pressure Dual-Fuel Engine
1987 – High-Pressure Gas Diesel Engine
1992 – Low-Pressure Spark-Ignited Engine
1970 1980 1990 2000 2010
Wärtsilä 2sDF engine development / milestones
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2010 Decision to start the 2sDF engine development
2011 Demonstration to the Licensees (single cylinder version)
2012/13 Full scale prototype tests
2013 Customer presentation in Trieste
2014 First contracts for RT-flex50DF + X62DF, orders for X72DF expected
2015 First FAT’s and sea trial RT-flex50DF
2016 Deliveries ramp up for 2sDF type engines
Gas admission system
Engine Control & Automation system
Micro-pilot common rail systemwith pre-chamber injector
Concept
A few key technologies make the difference...
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Concept
Principles
Engine operating according to the Otto process
Pre-mixed ‘Lean burn’ technology
Low pressure gas admission at ’mid stroke’
Ignition by pilot fuel in pre-chamber
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‘Pre-mixed lean-burn’ combustion
Scavenging Compression/ gas admission
Ignition expansion
Pilot ignition system
Electronically controlled injectors + common-rail fuel supplyPilot fuel (for ignition) only 1% -minimizing fuel costsPre-chamber technology for best combustion stability and reduced emissionsCurrent version only MDOFuel pressure 800-1200 bar, load dependent
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Pre-chamber
Pilot fuel system
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Pilot fuel pump unit
Pilot injectors
High pressure pipes double walled
Gas admission system
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Two gas admission valves (GAV) per cylinderGAV hydraulically actuated and electronically controlledHydraulic power from servo oil system (already existing for exhaust valve actuation)Double gas pipes (double walled-ventilated) on both sides of cylindersPrecise gas admission control – from full load to ’idling’Valve operation monitoredInspection interval: 6,000 RHOverhaul/replacement: min. 18,000 RHFinal value not yet defined, prolonged intervals are expected
Valve lift sensor
Low pressure DF - operation
Fuel mode transferTransfer to gas• Gradual, speed controlled transfer
from Diesel to Gas on load between ~ 5% to 85%Fully automatic transfer, just by pressing the push button “gas mode” on the bridge
Trip to diesel• The switch from gas to diesel is
instant ‘within 1 revolution’• At any load up to 100% to maximize
safetyEngine speed/load remains stable during transfer
Transfer to gas
Trip to diesel
Transfer back to gas
Trip to diesel
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Low pressure DF - operation
‘Port-to-port’ operation on gas
Entire voyage in gas mode
• Engine start on diesel for safety check
• Transfer to gas at low load/idling
• Transfer to diesel before stop
In case of FPP, reversing/restart will be done on diesel, then transfer back to gas
Engine Start/Stop in dieselaccording to the IGF-code (draft) and IACS rules.
Illustrative operating profile
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Emission picture
Comparison LP vs HPengine emissions
CO2 and SOx reduced in gas operation due to fuel composition
NOx very low with LP technology due to lower peak temperature
PM further reduced by the DF technology with lean-burn Otto combustion with pre-chamber ignition
Tier3!
-25% -25% -25%
-37%
-99%-96%
-98%
-85%
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LP HP
NOx emissions
Wärtsilä2sDF
Wärtsilä2sDF
Significant reduction of NOxemissions due to the low pressure DF technology
clearly below IMO Tier IIIwithout exhaust gas after treatmentport fee discounts
HP
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Source: Market-based Instruments for NOx abatement in the Baltic Sea by Per Kågeson
Wärtsilä4sDF
Wärtsilä4sDF
Safety aspects - Principles
Main systems to detect abnormal conditionsGas detectors (in double wall pipes, machinery space, on engine)Knocking sensorsCylinder pressure monitoring system
Possible system reactions upon detection of abnormal conditionsTrip back to diesel (back-up mode), all gas pipes vented,no pressurized gas on engineEngine slow-downEngine shut-down (only if impossible to runin back-up mode)
Back-up mode and system
redundancy of diesel engine is
always available!
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Safety principles as stipulated in the IGF-code (draft) and IACS rules
Machinery space concept – Gas safe engine room
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Dual-fuel engine machinery for Merchant Vessels
DF auxiliary enginesGas valve unit
G
G
G
Gas valve unit
Gas valve unit
Gas valve unit
LNGPacCyl.tank IMO C-type
Wärtsilä Package…..a complete and modularized solution for LNG fuelled ships
Low-speed DF main engine
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• Single wall pipe on open deck• Ventilated double wall piping following class rules for ‚inherently safe engine room‘
• Purging system for piping, GVU, tank,….
‘Tank room’ with 16 bar low-pressure pumps, evaporator, heater, valves, etc Low electrical energy
consumption for gas feed
Gas storage tanks
Single Shell(Submerged Pumps)
Double Shell(Cryogenic Pumps)
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Capacity range from 30-1000m³Tank material: Inner/outer tankaustenitic stainless steel or9% Ni steelOuter tank: function of secondary barrier, creating a double containment systemPerlite / Vacuum insulation or optionalMulti Layer Insulation / Vacuum
Capacity range from 600-2500m³Tank material: 9% Ni steel oraustenitic stainless steelDome on top of Tank for all tank pipeconnections above maximum liquid levelTank Connection Space separated fromtank
Construction
Installation
Commissioning
Operation
Source: Sinopacific
System provider
Full flexibility tank designs for every marine & offshore vessel applicationExperience with
Wärtsilä fully automated and integrated LNGPacTM system provider
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Engine rating fields
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Covered vessel segments:
• LNG Carriers
• Container Vessels1000 – 18000 TEU
•Tankers• Product• Aframax• Suezmax• VLCC
• Bulkers• Handysize• Handymax• Panamax• Kamsarmax• Capesize• VLOC
• PCTC, CONRO
• Ship type 4 x 15,000 dwt Chemical Tankers, 14.5 kn (vDES) • Owner Terntank Rederi AS, Sweden• Shipyard AVIC Dingheng Shipbuilding Co, China• Vessel delivery Q2, 2016• Engine type Wärtsilä 5RT-flex50DF, CMCR of 5850 kW
INTO the FUTURE - Baltic SO2lution
Leading into the Gas Age – Reference 1
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Leading into the Gas Age – Reference 2
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First costal LNG Carrier with 2sDF engine• Ship type 14,000 m3 LNG Carrier, 15 kn (vDES) • Owner Zhejiang Huaxiang Shipping Co., Ltd
• Private shipping company• Major player in LPG transportation market• One of the operators of LNG transportation in China domestic water
• Shipyard Qidong Fengshun Ship Heavy Co., Ltd, • Vessel delivery 2015• Engine type Wärtsilä 5RT-flex50DF, CMCR of 6000 kW
Leading into the Gas Age – Reference 3
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First LNG- fuelled Container Feeder Vessel for Baltic Sea operation• Ship type 3 (+1+2) x 1400 TEU C/V, 18.5 kn (vDES), iceclass 1A • Owners GNS Shipping / Nordic Hamburg, Germany• Charter Containerships, Finland• Shipyard Yangzhou Guoyu Shipbuilding, China• Vessel delivery Q3, 2016
• Engine type Wärtsilä 7RT-flex50DFCMCR of 10070 kW6L20DF generating setMCR of 1055 kW
Leading into the Gas Age – Reference 4
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First LNG Carrier with low-speed LOW-PRESSURE DF engine• Ship type 2 x 180,000 m3 LNG Carrier, 19.5 kn (vDES)
Twin-skeg, twin-screw
• Owners SK Shipping, KoreaMarubeni Corporation, Japan
• Charter Total SA, France
• Shipyard Samsung Heavy Industries, Korea
• Vessel delivery Q1, 2017
• Engine type Wärtsilä 2 x 6X62DF main enginesCMCR of 13450 kW eachWärtsilä 4 x L34DF gensets
Conclusions
Why to choose a Wärtsilä low-pressure dual-fuel engine:
1) Meets IMO Tier III requirements without exhaust gas after-treatment due to lean burn Otto combustion process
2) Low CAPEX due to low pressure gas supply system• No large pressurization and high pressure equipment• No exhaust gas after treatment
3) Low OPEX due to high overall efficiency (low parasitic loads)
4) Full Wärtsilä Package - Complete and modularized solutions for LNG fuelled ships
5) Retrofit for existing RT-flex50-D, X52, X62, X72, X82 will be made available depending on market demand
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THANK YOU!
WärtsiläWärtsiläLeading gas applications in the marine marketLeading gas applications in the marine market
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