ethane, methanol, and lpg as marine fuel. - intertanko lng wg feb 2013/dnvgl met… · ethane,...
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DNV GL © 2013 12th February 2015 SAFER, SMARTER, GREENER DNV GL © 2013
12th February 2015
Olav Tveit
MARITIME
Ethane, Methanol, and LPG as Marine Fuel.
1
ISTEC WG on Alternative Fuels
DNV GL © 2013 12th February 2015
IGF code development
The IGF code opens for low-flashpoint fuels
given compliance with chapter 2,3,4:
– Equivalent safety level demonstrated by
risk assessment.
– High level goals and functional
requirements.
Prescriptive requirements for natural gas
fuel only.
Sweden to coordinate phase 2 work
package to follow up development on
Methanol, Ethanol, low flashpoint diesel and
fuel cells.
2
From the draft IGF code:
3.2 Functional requirements
3.2.1 The safety, reliability and dependability of
the systems shall be equivalent to that
achieved with new and comparable
conventional oil‐fuelled main and auxiliary
machinery
4 General requirements
4.2.1 A risk assessment shall be conducted to
ensure that risks arising from the use of
gas‐fuel or low‐flashpoint fuels affecting persons
on board, the environment, the structural
strength or the integrity of the ship are
addressed. Consideration shall be given to the
hazards associated with physical layout,
operation, and maintenance, following any
reasonably foreseeable failure.
DNV GL © 2013 12th February 2015
LFL Fuelled Ship Installations
LFL Fuelled Ship Installations
Gas Fuelled Ship Installations
Main Class Fuel Cell Installations
Battery Power
DNV GL Rule development
3
DNV GL © 2013 12th February 2015
Ethane carriers
Regulatory:
– Not covered by IGC code. Requires Flag State acceptance.
6
DNV GL © 2013 12th February 2015
Ethane carriers
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DNV GL © 2013 12th February 2015
Ethane carriers
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DNV GL © 2013 12th February 2015
Ethane carrier tank types
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DNV GL © 2013 12th February 2015
Ethane carriers
MAN-GI adapted for Ethane.
NOx abatement may be required.
High supply pressure: 550 bar vs. 300 bar (LNG).
Norwegian Authorities have accepted Ethane as
fuel based on IGC code equivalence with additional
requirements:
– Additional barriers related to cryogenic hazards
and high pressure leaks (Hazid results).
– Gas detection also in lower parts of ER (Ethane
marginally heavier than air).
Power generation:
– AE (4-stroke) alternatives ? (Wartsila GD).
– Shaft generator.
Boiler technology available.
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DNV GL © 2013 12th February 2015
LFL fuelled ships
Regulatory:
– Not covered by IGF code. Requires Flag
State acceptance.
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DNV GL © 2013 12th February 2015
Methanol fuel properties
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Properties Methanol
CH3OH Diesel fuels
C8-C25 Methane
CH4
Flash point (°C) 12 > 60 -187
Boiling point (°C) 65 180-360 -162
Lower heating value (MJ/kg) 19,9 41-42 48,6
Flammability limits (% in air)
LEL 6.7 0.6 5
UEL 36 7.5 15
Autoignition (°C) 470 250-450
540
Cetane no. <5 38-53
Density (kg/m3) 796 860 420
Data sources: -DNV GL Position Paper 17-2014, Alternative Fuels for Ships Hess Material Datasheet, Murphy, Michael J (1994) and Pitblado et al., 2006 and Stokes H -MAN Diesel & Turbo -Methanex, Technical Information & Safe Handling Guide for Methanol
1. Study fuel properties
2. Map the risks
3. Design system
4. Formal safety assessment
DNV GL © 2013 12th February 2015
The risks are known in the industry
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Chemical tankers Offshore supply Gas fuel
Burns with an invisible flame Toxicity Detectability Lubrication/Viscosity Methanol vapor is heavier than air Corrosivity ? Emissions (Formaldehyde & Formic acid) ?
DNV GL © 2013 12th February 2015
Methanol fuel
Standard chem.tanker
requirements to
containment.
Segregated LFL fuel tanks
and piping systems.
IGF code principles.
10 bar supply pressure
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DNV GL © 2013 12th February 2015
Methanol fuel
Norwegian Authorities have accepted Ethane
as fuel based on IGF code equivalence with
additional requirements:
– Systems and arrangements reflecting that
methanol vapour is heavier than air).
– Methanol is liquid, not gas. I.e. purging,
leakage and drainage issues.
MAN-LGI engine.
NOx abatement may be required.
High injection pressure: 600 bar
AE (4-stroke) alternatives (Watsila Z40S, GD)
Boiler technology ?
15
DNV GL © 2013 12th February 2015
VOC fuelled ships
Regulatory:
– Not covered by IGF code. Requires Flag State acceptance.
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DNV GL © 2013 12th February 2015
VOC as fuel
VOC streams:
– Surplus VOC gas from cargo tanks (12-16 000 m3/h VOC+IG @ 20-80% mix)
– Liquefied VOC (LVOC ~ LPG) from LVOC tank (200-500 m3)
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LVOC composition
Methane (C1) Ethane (C2) Propane (C3) Butane (C4) Pentane (C5) C6 C7+
Gullfaks 0,01 0,04 7,4 45,9 27,3 13,6 5,7
VOC composition (based on condensation plant baseline from 2000)
Methane (C1) Ethane (C2) Propane (C3) i-Butane (C4) n-Butane (C5) i-Pentane (C5) n-Pentane (C5) Hexane (C6) Condensable (C3-C6) Surplus VOC (ex. IG)
Statfjord 5,7 15,4 39,6 7,1 20,3 4,4 5,4 2,6 79,40 % 21,10 %
Gullfaks 22,9 23,6 27,3 5,6 11,6 3,3 3,3 2,8 53,90 % 46,50 %
DNV GL © 2013 12th February 2015
VOC utilization alternatives
Discharge with Cargo
Boiler fuel – Heating, IG, Power generation (T/G), Cargo & Ballast pumps turbines
Gas turbine fuel – Power generation to grid.
DF aux. engine fuel (4-stroke) – Power generation to grid.
DF M/E fuel (2-stroke) – Propulsion (+ shaft generator for power to grid)
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DNV GL © 2013 12th February 2015
Current Steam system
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DNV GL © 2013 12th February 2015
2-stroke engine alternatives.
M/E alternatives (2-stroke):
– As surplus VOC is only generated during loading, it is assumed that surplus VOC
operation on direct driven M/E is not very feasible.
– Surplus VOC: No available technology
– LVOC: MAN ME-LGI
– Reformed LVOC*: DF engines can be used
* Steam reformed gas with enhanced methane number
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DNV GL © 2013 12th February 2015
4-stroke engine alternatives
Engine alternatives for VOC (4-stroke):
– Surplus VOC: No available technology
– LVOC: Wartsila GD ?
– Reformed LVOC*: DF engines can be used.
* Steam reformed gas with enhanced methane number
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DNV GL © 2013 12th February 2015
Engine alternatives.
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DNV GL © 2013 12th February 2015
Gas turbines
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DNV GL © 2013 12th February 2015
Gas turbines
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Low pressure gas turbines considerations:
Fuel flexibility (Surplus VOC, LVOC, Standard Fuel)
Compact (small footprint and high power/weight ratio)
Low NOx (25 ppm)
Thermal efficiency lower than engines (waste heat generation)
Proven technology offshore
Surface temp. issues.
ESD-engine room issues
DNV GL © 2013 12th February 2015
Engine alternatives.
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