ethane, methanol, and lpg as marine fuel. - intertanko lng wg feb 2013/dnvgl met… · ethane,...

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.

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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.


LFL Fuelled Ship Installations

LFL Fuelled Ship Installations

Gas Fuelled Ship Installations

Main Class Fuel Cell Installations

Battery Power

DNV GL Rule development

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Ethane carriers

Regulatory:

– Not covered by IGC code. Requires Flag State acceptance.

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Ethane carriers

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Ethane carriers

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Ethane carrier tank types

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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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LFL fuelled ships

Regulatory:

– Not covered by IGF code. Requires Flag

State acceptance.

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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


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) ?


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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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 ?

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VOC fuelled ships

Regulatory:

– Not covered by IGF code. Requires Flag State acceptance.

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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 %


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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Current Steam system

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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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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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Engine alternatives.

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Gas turbines

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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


Engine alternatives.

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ethane, methanol, and lpg as marine fuel. - intertanko lng wg feb 2013/dnvgl met… · ethane,...

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