MAN B&W two-stroke engine operating on ammonia - LNG
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O2
H2 NH3
Electrolysis
O2
Air N2
separation
CO2 CCS
Steam
reforming
H2 NH3
LNG
O2
Air N2
separation
MAN B&W
two-stroke engine
operating on
ammonia
2 MAN Energy Solutions
MAN B&W two-stroke engine operating on ammonia
Future
in the
making3 Contents 1. Introduction 05 2. United effort towards a future decarbonising fuel 06 3. Reflections on ammonia as a future two-stroke marine fuel 07 4. In the process of developing the first two-stroke, dual-fuelled engine for ammonia 10 5. Summary and Outlook 14 6. Bibliography 15 7. Acronyms and abbreviations 16
4 MAN Energy Solutions
MAN B&W two-stroke engine operating on ammonia
Ammonia as a marine fuel is put into perspective as
this paper presents our current knowledge about
ammonia as a potential long-term fuel for
two-stroke marine engines. We address the
challenges encountered by the maritime market,
which are best described as a paradigm shift to
ensure compliance with global decarbonisation
goals.
To develop an engine for a new fuel such as
ammonia calls for partnerships, cooperation and an
understanding of the market interests. MAN Energy
Solutions works diligently towards designing the
MAN B&W engine for operation on ammonia and
offering retrofit conversions of existing two-stroke
engines to ammonia.
Decarbonisation constitutes one of the largest
transitions encountered, and the short deadline to
succeed requires a united and committed approach
from the entire supply chain from well to wake.5
1. Introduction
One of the future fuel candidates Another distinctive feature is the ability ignition, combustion and emission as
receiving a growing global interest and to operate on almost any fuel or fuel well as fuel handling.
likely to play a significant role in the quality with no or limited decrease in
decarbonisation is ammonia (NH3). Our efficiency and with the reliable Therefore, research of ammonia as a
aim with this paper is to share our performance and operating fuel for two-stroke engines involves
current knowledge about ammonia as a characteristics as the conventional extensive testing with a complete
potential long-term fuel for two-stroke two-stroke engine even in adverse engine monitoring setup to achieve
marine engines and to give a new weather conditions. fundamental information about, for
update on the development of an example, the ignition properties of
ammonia-based propulsion. The fundamental reasons for the large ammonia in a two-stroke engine, pilot
tolerance to poorly ignitable and fuel requirements and emissions. These
Thanks to the carbon- and sulphur-free burning fuels are the low speed of the research results will govern the final
molecular composition of NH3, burning engine, allowing time for the design of the ammonia-burning engine
it in an engine creates near-zero CO2 combustion to finish, and the large and auxiliary systems.
and SOX emissions. From a dimensions, leading to large
well-to-wake perspective, ammonia volume-to-surface ratios, which is
becomes a carbon-neutral fuel when beneficial for a complete combustion
produced from renewable energy and low wall heat losses.
sources like electricity produced from
hydropower, wind or solar energy. The beneficial carbon-free nature of
Furthermore, emission of air pollutants ammonia also implicates that ammonia
related to carbon (black carbon or soot, combustion physics will not fully
unburned hydrocarbons (HC), methane resemble the combustion
slip and carbon monoxide (CO)) will be characteristics of previously known
virtually eliminated. two-stroke fuels. To provide our
customers with an optimised and
One of the characteristics defining the reliable engine of the well-known MAN
two-stroke engine portfolio of MAN ES standard, it is vital to research the
Energy Solutions (MAN ES) in Fig. 1 is entire propulsion solution and the
the fuel diversity. two-stroke engine processes, that is,
LNG Ethane Methanol LPG Ammonia
ME-GI ME-GA ME-GIE ME-LGIM ME-LGIP → 2024
Fig. 1 MAN B&W dual-fuel two-stroke engine portfolio6 MAN Energy Solutions
MAN B&W two-stroke engine operating on ammonia
2. United effort towards a future decarbonising fuel
At MAN ES, we are committed to and engine components. In addition, Furthermore, besides working closely
continuously optimise the MAN ES will provide the engine test together with our licensee Mitsui
environmental impact of our engines. bed and conduct the engine trial run. Engineering & Shipbuilding in a
To develop an engine for new fuels partnership agreement we also work
such as ammonia calls for partnerships As a step on the transition path towards together with different universities.
and an understanding of the market decarbonisation, Maersk, MAN Energy
interests. An analysis of the actual Solutions and five partners have joined
potential is also essential before forces in launching the Maersk
starting the development of the Mc-Kinney Moller Center for Zero
ammonia engine. In this case, the fuel Carbon Shipping in Copenhagen [2].
can enter the market as an intermediate Brian Østergaard Sørensen, Vice
fuel until green ammonia is available President and Head of R&D Two-Stroke
and the logistics are in place. Business at MAN Energy Solutions, has
framed the nature and successful
Another uncertain and most essential progress of the present task:
parameter in the decision of the future
fuel is the prices of the future fuels. On “Decarbonisation will be one of the
the one hand, if green ammonia was largest transitions that we will see
available today, it would be several within the maritime industry for years
times more expensive than and requires a holistic approach looking
very-low-sulphur fuel oil (VLSFO) and at the complete supply chain from well
LNG. On the other hand, we to wake. No technology or company
acknowledge that the marine market can do this alone, which is why we
widely understands that if CO2 and need to join forces across the supply
greenhouse gas (GHG) footprints are to chain to meet this challenge. We at
be reduced for the foreseeable future, MAN Energy Solutions have
some kind of international regulation of decarbonisation as part of our
the CO2 and GHG emissions needs to corporate strategy, and developing
come into force. sustainable technologies and solutions
is at the core of what we do. While
We have entered into commitments two-stroke engine technology will likely
with other players to investigate the remain the prime mover for deep-sea
opportunity for ammonia as the coming shipping, cleaner fuels will play a larger
future fuel and hydrogen carrier. role in the future. MAN Energy Solutions
recognises that there are several
In this connection, we are happy to pathways to achieving a carbon-neutral
announce that the Innovation Fund economy and that we need to work
Denmark has decided to support the together, which is why we are happy to
development within the framework of have joined the Center.”
the project AEngine, the project’s aim
being the design and demonstration of The Maersk Mc-Kinney Moller Center
an ammonia-based propulsion system. for Zero Carbon Shipping will be an
MAN ES is the AEngine project independent research centre, bringing
coordinator and a part of the together stakeholders from the shipping
cross-functional project team together sector, industry, academia and
with Eltronic FuelTech (fuel supply authorities. A highly specialised,
systems), the Technical University of cross-disciplinary team will collaborate
Denmark and the classification society globally to create overviews of
DNV GL [1]. decarbonisation pathways, accelerate
the development of selected
MAN ES will integrate existing technolo- decarbonising fuels and powering
gy in the ammonia-based propulsion technologies, and support the
system while designing the ammonia establishment of regulatory, financial
fuel injection, combustion components, and commercial means to enable the
exhaust gas after-treatment technology transformation.7
3. Reflections on ammonia as a future two-stroke marine fuel
Physical/chemical properties of hydrocarbons or from electrolysis of temperature (20°C). To keep it in the
ammonia govern many of the design water, as outlined in more detail below. liquid phase if the ambient temperature
aspects of an ammonia-fuelled increases, it is common to design
propulsion system and auxiliary For comparison, Table 1 shows the non-refrigerated ammonia tanks for
systems, including storage. physical properties of ammonia, other approximately 18 bar.
alternative fuels, and MGO.
Vessel owners have to consider
ammonia storage and availability, Currently, parameters for fuel supply 3.2 Transition towards a green
vessel trade pattern and related and injection pressures for NH3 are 80 ammonia production
emission regulations combined with an bar and 600–700 bar, respectively.
increased focus on the environmental However, these parameters make up Although it is in the nature of things that
impact of the vessels. the topics of further research and combustion of ammonia emits no CO2,
optimisation in the engine test scheme. as it contains no carbon atoms,
large-scale industrial productions of
3.1 Physical properties A comparison of the properties related ammonia is based mainly on a fossil
to storage in Table 1 shows that fuel feedstock for grey and blue
Generally, ammonia is produced via the hydrogen (H2) liquefies when cooled to ammonia production. This conventional
Haber-Bosch synthesis process from temperatures below -253°C, and LNG ammonia production produces CO2 as
hydrogen and nitrogen. While the at -162°C. By contrast, ammonia a by-product. Blue ammonia
nitrogen comes from air separation, a liquefies already at -33°C. production involves capture of the
number of production routes can be generated CO2, which is liquefied and
used to produce hydrogen, most Liquid ammonia can be stored at a stored using the carbon capture and
prominently from steam reforming of pressure above 8.6 bar at ambient storage (CCS) principles.
Energy Energy Fuel tank size Supply Emission reduction
Energy storage type/chemical structure content, LHV density relative to MGO pressure compared to HFO Tier II [%]
[MJ/kg] [MJ/L] [bar] SOX NOX CO2 PM
Ammonia (NH 3) 18.6 12.7(-33°C) 2.8 (-33°C)*1 Compliant
(liquid, -33°C) 10.6 (45°C ) 3.4 (45°C)*1 80 100 with regulation ~90 ~90
Methanol (CH 3 OH)
(65°C) 19.9 14.9 2.4 10 90–97 30–50 11 90
LPG (liquid, -42°C) 46.0 26.7 1.3 *2 50 90–100 10–15 13–18 90
LNG (liquid, -162°C) 50.0 21.2 1.7 *2 300 90–99 20–30 24 90
LEG (liquid, -89°C) 47.5 25.8 1.4 *2 380 90–97 30–50 15 90
MGO 42.7 35.7 1.0 7–8
Hydrogen (H 2) (liquid, -253°C) 120 8.5 4.2
1)
The relative fuel tank size for ammonia has been provided for both cooled (-33°C) and pressurised tanks (45°C)
2)
Assuming fully refrigerated media
Table 1: Alternative fuel comparison8 MAN Energy Solutions
MAN B&W two-stroke engine operating on ammonia
However, ammonia has the potential to However, when it comes to the – It is less expensive and less complex
become the sustainable future fuel ammonia synthesis, the Haber-Bosch to transport and store than hydrogen
choice, when it is produced using process is still the industrially applied and other fuels in need of cryogenic
hydrogen obtained by using renewal method. temperatures
energy sources, see Fig. 2.
– T
he low risk of ignition in ambient
Ammonia (or anhydrous ammonia) is a 3.3 Challenges and advantages of an atmosphere makes the storage of
globally traded commodity. The annual ammonia fuel large quantities of ammonia safer
global ammonia production is than hydrogen in terms of fire safety
approximately 180 million tonnes, of There are challenges but also
which approximately 80% becomes advantages associated with storage, The lower heating value of approxi-
feedstock for fertiliser production [3]. transport and combustion of ammonia mately 18.6 MJ/kg for ammonia is com-
Therefore, transport and storage of governed by the physical and chemical parable to methanol. The energy densi-
ammonia from production facilities to properties [3], see also Table 1: ty per unit volume of ammonia (12.7
end users have been going on for MJ/L) and the other alternative fuels, is
years. H3 is carbon- and sulphur-free and
– N lower than that of MGO (35 MJ/L). To
gives a clean combustion with carry the same energy content of am-
3.2.1 Electrolysis of water near-zero generation of CO2 or SOX monia relative to MGO will require an
To produce sustainable green ammonia approximately 2.8 times larger volume
using hydrogen obtained by electrolysis – T
he volumetric energy density of NH3 if the ammonia tank is cooled.
of water (2H2O → 2H2 + O2), the is higher than for H2
electricity must be produced using only Although ammonia has the potential to
renewable energy sources. – NH3 can be cracked to N2 and H2 become the future fuel, it is a toxic
substance that, regulation-wise, has
3.2.2 Nitrogen separation from air – NH3 is non-explosive unlike H2 not yet been released for use as a
Separation of nitrogen from air for marine fuel.
ammonia production takes place via – T
he widespread use of ammonia in
various technologies depending on the industrial processes and as an
required purity and amount of agricultural fertiliser means that it is 3.4 Trends in marine fuels
ammonia. In large-scale productions of already a commercially attractive
nitrogen, air is liquefied and separated product As phrased by Kjeld Aabo, Director of
into its constituents. New Technologies, Sales and
O2
H2
Electrolysis
O2
Air
separation
N2
Fig. 2: Illustration of green ammonia production9
Promotion, Two-stroke Marine at MAN are aware that the transition requires the next few years, a regulation of both
Energy Solutions: “No one can afford to new fuels instead of the fuels we know existing and new vessels might be
go green alone“. today. The shipowners face a complex expected. Not to the same extent, but
puzzle in the light of carbon-free or in a way that allows the environment
Introduction of regulation initiatives will carbon-neutral fuel prices several times the impeding benefit from the CO2
be one of the cornerstones of the higher than the fuel oil prices today, emission reduction, and at the same
transition. To incentivise the industry to and the fact that fuel often makes up time, avoids distorting the industry.
invest in equipment for future fuels, the largest operational cost for vessels.
regulation initiatives governed by When looking at the market, we have
subsidies, CO2 or GHG taxes have to 3.4.2 Regulation initiatives picked up a distinct preference for
be introduced. For future CO2-emission-free fuels to ammonia compared to hydrogen. The
become attractive, the fuel prices, explosion risk is one argument, but the
The general public opinion is that the when considering all costs/incentives, discussion more often concerns the
global warming challenge needs to be must be comparable with traditional actual handling of hydrogen and the
addressed and that the maritime fuel prices. If achieved by a CO2 /GHG cost of handling ashore and onboard.
industry must contribute to the CO2 regulation as mentioned, the period for Another important aspect is the high
emission reduction. Today, the maritime engine conversion to a future fuel can energy consumption required to liquefy
industry accounts for 3-4% of the be short, once the regulation becomes hydrogen at -253°C, a more efficient
global human-caused CO2 emission. effective, and the implications to approach is to use the hydrogen gas in
The existing fleet consumes close to shipowners and yards must not be the production of ammonia, which
300 million tonnes of fuel oil annually. underestimated. liquefies at -33°C. Handling of
However, it also plays a fundamental hydrogen is complicated and expensive
role in the global economy, transporting The question remains whether a part of compared to the ammonia solution.
more than 80% of the world’s total the existing fleet will be CO2 /GHG Engineering a practical solution for
trade volume [3]. regulated even stricter than required by handling hydrogen that can be adapted
the energy-efficiency design index to a typical two-stroke engine room is
3.4.1 Prediction of the future fuel (EEDI) or the energy-efficiency not without its hurdles. Still, many
It is difficult, if not impossible, to operational indicator (EEOI), or if projects are ongoing and continuously
predict which fuels will carry off the title regulations will apply only to new increasing in number. The projects
as future fuels. Since the future cost of vessels from a certain date [4]. Based concern the development of production
different fuels is hard to predict, the on the assumption that CO2 /GHG facilities, logistics, propulsion plant
shipowners want to be prepared. They regulations will become effective within engines, and fuel supply systems (FSS)
to handle ammonia.
The early, considerable, and increasing
interest in using ammonia as a fuel
made it part of the zero-emission
strategy of MAN ES to investigate and
provide technology that utilises
ammonia as fuel.
3.4.3 Ammonia fuel mixture
Today, many of the vessels delivered
are ready for later dual-fuel adaption,
as the engine builders are ready or
working on being ready to retrofit their
NH3 engine design accordingly. Although
the anticipation is that fossil fuels will
remain in the maritime industry for
many years to come, especially during
the transient period from 2020 through
2050, the possibility exists to run on
grey or blue ammonia or any mixture of
either of these and green ammonia.
This possibility will lower the risk
related to investing in a ship operating
on ammonia, since conventional
ammonia is a commercial commodity
traded in large quantities.10 MAN Energy Solutions
MAN B&W two-stroke engine operating on ammonia
4. In the process of developing the first two-stroke,
dual-fuelled engine for ammonia
As Fig. 3 shows, one of the We started a pre-study of the fuel in general. We will finalise the
characteristics describing the supply and injection concept and development process of the ammonia
two-stroke engine portfolio of MAN ES conducted several hazard identification, engine in 2021 and the commercial
is the fuel diversity. The development of and hazard and operability studies design verification is scheduled for
the MAN B&W two-stroke engine has (hazid/hazop) together with 2023. When the engine design is
since the beginning been adapted to classification societies, shipowners, released, the first engine can be
combust diverse fuel types. yards and system suppliers. prepared for test bed. The ammonia
development project reaches a major
In 2019, the journey towards a Presently, we are working on verifying milestone when the first ammonia
two-stroke engine operating on the development concept of the engine is installed in a vessel during the
ammonia began, as illustrated in Fig. 4. injection system and the engine design first six months of 2024.
Engine delivery Engine delivery ME-GI retrofit First sea trial First sea trial First order of MAN 4 x MAN B&W ME Hapaq Lloyd
for TOTE Maritime for TEEKAY LNG for Nakilat on methanol ethane B&W6G60ME-LGIP LGIP retrofit orders 9S90ME-C ME-GI
engines by Exmar for BW LPG, retrofit, dry dock
dry dock 2020 2020
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
ME-GI test at Demonstration Demonstration Development Ethane ME-GI/E PVU LPG testrig at LPG tightness LGIP cylinder
Research Centre test at HHI test at MES of ME-LGI development at RRC RCC and function installed on the ME-GA multi-fuel
Copenhagen (RCC) test at RCC research engine &
at RCC ammonia engine
Fig. 3: Fuel diversity and engine types
2019 2020 2021 2022 2023 2024
Pre-study Project kick-off 1st engine test Emission Full scale engine 1st engine
specification test delivery to yard
✓ N
H 3 combustibility ✓ 4
T50ME-X test st engine
– 1
investigation. engine received as confirmation at – S
pecification of – F
ull scale engine mmonia engine
– A
platform for the Research Centre emission test at RCC in engine
Ammonia engine Copenhagen after-treatment completed. programme.
development. (RCC). done.
st ammonia
– 1
✓ H
AZID workshop ngine basic
– E burning engine to
on engine concept defined be installed at
concept. based on engine yard.
tests.
mmonia supply &
– A
Auxiliary systems
specified
Fig. 4: Two-stroke ammonia engine development schedule11
4.1 Engine foundation tage of the ammonia-fuelled low-speed In principle, the main differences
two-stroke engine is that it will not between the fuel characteristics
When designing an engine governed fundamentally change merchant governing the ME-LGIP and the
by altered combustion physics due to shipbuilding or operation, and thus a ammonia engine designs are related to
the chemical composition of a new simple and well-engineered solution is heating values, the foul odour, and the
fuel, it requires thorough research of in place to cater for the requirements corrosive nature of ammonia:
the influence on all conceivable engine of this novel fuel.
design parameters to provide an – lower calorific values (LCV) of the
efficient and safe engine and fuel The findings will also govern the FSS fuels:
supply system to the customers. configuration. Although the first tests ⎼ 46.4 MJ/kg for propane (LPG)
of the engine will be concluded in ⎼ 18.6 MJ/kg for ammonia
Currently, MAN ES carries out research 2021, and the FSS design must be
in the Research Centre Copenhagen adapted to the outcome, we assume – a
mmonia is corrosive to copper,
(RCC) and in different partnerships to that the configuration for ammonia will copper alloys, alloys with a nickel
assess combustion and heat release inherit main features from the concentration larger than 6%, and
characteristics of ammonia. The well-known LGP supply system for plastic
findings of the research will guide the liquid injection.
development of the specific fuel The ideal solution is to reuse part of the
injection properties and clarify the The ultimate design of the FSS requires dual-fuel LPG injection system on the
nature of two-stroke emissions, when final confirmation, but we have started ammonia engine and part of the LPG
operating on ammonia. the development to have a supply fuel supply system from tank to engine
system ready for the engine. The fuel [5]. Again, an affirmative engine test in
Ammonia is a toxic substance, and supply system for the ME-LGIP engine 2021 is required, but in the following,
proper safety measures must be in being the starting point. the design has been based on the fuel
place to safeguard the ship’s crew and supply system for the ME-LGIP engine.
the surrounding environment. In As for the engine, development of an
addition to catering for these FSS calls for a safe and reliable design
requirements, MAN ES brings based on the outcome of hazid and 4.2 Fuel supply system
technology to the market that is hazop investigations. Currently, we considerations
engineered to adapt to the skills and have performed three hazid
work routines of the engineering crew investigations observed by Fig. 5 and the following sections
and the resources onboard. This is representatives from the classification highlight the main principles of the fuel
achieved without fundamentally societies, shipowners, yards and supply system for the ammonia engine
changing the ship operation. An advan- suppliers of components for the FSS. and dual-fuel operation.
Amminia catch N2 vent
system
Vent air outlet
Recirculation Dry air inlet
system Knock-out
drum
Knock-out (engine)
LT drum HC FS
(system) FVT
Gas
safe
area ▸
FSS
LS
HP Heater/
cooler Gas
From NH3 pump safe
supply system area ▸
MAN B&W
engine
Nitrogen
Cooling supply
water
Fig. 5 Principles of the ammonia supply system showing main components12 MAN Energy Solutions
MAN B&W two-stroke engine operating on ammonia
4.2.1 Principles of dual-fuel necessary to ensure that ammonia fuel comparable to a conventional
operation is delivered to the engine at the low-speed diesel engine. However, the
During dual-fuel operation, the required temperature, pressure and pathway of NOX production during
ammonia fuel supply to the engine quality. In most cases, the FSS has a combustion is quite different from the
comes from the storage tanks via the high-pressure pump, a heater, filters, conventional engine, and hence also
fuel supply system. To maintain the valves and control systems to maintain the sensitivity to changes in engine
required fuel conditions at the engine, a the ammonia fuel pressure and performance.
small portion of the ammonia fuel temperature at varying engine
continuously recirculates to the FSS via consumptions. Obviously, ammonia will only be an
the recirculation system. environmentally viable fuel if the
4.2.4 Fuel valve train emissions known from a conventional
When the engine is not in dual-fuel The fuel valve train (FVT) is the engine are not merely replaced with
mode, the double block-and-bleed interface between the engine and the other types of harmful emissions.
arrangements of the FVT depressurise auxiliary systems. The purpose of the Naturally, it is an important part of the
and completely isolate the ammonia FVT is to ensure a safe isolation of the MAN ES development effort to ensure
fuel systems inside the engine room engine during shutdown and that only very low levels of any
from the ammonia fuel supply and maintenance, and to provide a problematic emissions escape from the
return systems. Before every start, the nitrogen-purging functionality. This ammonia engine, and that the new fuel
systems are pressurised with nitrogen functionality ensures a safe will not create a new problem for the
to verify the tightness of the system. environment on the engine after shipping industry to consider.
shutdown.
When dual-fuel operation stops, the 4.3.1 Selective catalytic reduction
nitrogen pressure pushes back the 4.2.5 Nitrogen system technology
ammonia fuel from the engine to the Nitrogen must be available for purging To reduce emissions of nitrogen oxides
recirculation system. When the purging the engine after dual-fuel operation, for (that is, NO and NO2, commonly
sequence is complete, the FVT will gas freeing prior to maintenance and referred to as NOX) and to fulfil the
once again ensure the isolation of for tightness testing after maintenance. regionally different emission
engine room systems from the supply The capacity of the nitrogen system regulations, MAN ES engines have
and return systems. must be large enough to deliver a been equipped with, for example,
certain flow at a pressure higher than advanced SCR (selective catalytic
Throughout the entire operation, the the service tank pressure. reduction) technology. The SCR system
double-walled ventilation system from using ammonia was introduced in the
existing MAN ES dual-fuel engines 4.2.6 Double-walled ventilation 1990s in four bulk carriers. Pending the
detects any ammonia fuel leakage and system outcome of the first engine test results,
directs it away from the engine room to To maintain a safe engine room, it is an increase in SCR volume and
a separate ammonia trapping system. vital to detect any leakages from the ammonia consumption may be
ammonia fuel system and direct these necessary to achieve compliance in
4.2.2 Recirculation system to a safe location. This has led to the Tier III mode.
The recirculated ammonia fuel will heat double-walled design of ammonia fuel
up in the engine during operation. To systems and piping inside the engine The SCR technology is an
avoid two-phase conditions, a certain room. A constant flow of ventilation air after-treatment process, where NOX
amount of the ammonia fuel is is kept in the outer pipe in accordance formed during the combustion is
recirculated to a dedicated recirculation with IMO requirements. The system is removed from the exhaust gas in a
line. The same recirculation line already part of other MAN B&W catalytic reduction.
recovers the ammonia fuel from the dual-fuel engine designs.
engine whenever dual-fuel operation is Normally, the ammonia (reducing agent)
stopped. 4.2.7 Ammonia capture system required is added by injecting a urea
The ammonia systems must be solution (CH4N2O + H2O) into the
The recirculated fuel may contain designed with an ammonia capture exhaust gas, however, ammonia can be
traces of sealing oil from the injection system to prevent release of ammonia injected as the catalytic agent instead
valves. The recirculation line eliminates to the surroundings. of urea. One of the benefits of this is
the risk of contaminating fuel storage that an ammonia-fuelled vessel already
tanks with oil. The recirculation line also carries ammonia. The consumption of
separates and bleeds off nitrogen from 4.3 Emission reduction technologies ammonia for the SCR system will be
the recovered ammonia fuel. very small compared to the ammonia
It is expected, that the raw engine NOX fuel consumption.
4.2.3 Fuel supply system emission level of a two-stroke engine
The FSS contains the equipment running on ammonia will be at a level13
Fig. 6 outlines the principle of selective NO
Exhaust gas
catalytic reduction of the NOX content NO2
NH3
in the exhaust gas.
NH3
In the catalytic reaction, NH3 and NOX
This SCR process
are converted to diatomic nitrogen (N2) requires ammonia
and water (H2O): in order to work SCR
reactor
4NO + 4NH3 + O2 → 4N2 + 6H2O
6NO2 + 8NH3 → 7N2 + 12H2O
By ensuring a complete combustion, N2
the emission of unburned NH3 H2O
(ammonia slip) and the formation of
nitrous oxide (N2O) will be minimised. Fig. 6: The selective catalytic reduction process14 MAN Energy Solutions
MAN B&W two-stroke engine operating on ammonia
5. Summary and Outlook
Decarbonisation is a central and highly future market demands for CO2-neutral
integrated part of developing propulsion including retrofits.
sustainable technologies and solutions
at MAN ES. However, as The future installation of an
decarbonisation remains a global ammonia-combusting engine can be
endeavour and one of the largest adapted to the customer, for example
transitions within the maritime world, it as a dual-fuel, modular retrofit solution
will require a united maritime industry for existing electronically controlled
to question and evaluate the entire engines, as an ammonia-ready engine,
supply chain. or from newbuilding.
The Innovation Fund Denmark supports The engine design and FSS
the AEngine project with the aim to configuration for ammonia will be
design and demonstrate an based on the testing in 2021.
ammonia-based propulsion system.
MAN ES is the AEngine project MAN Energy Solutions works diligently
coordinator and part of the towards offering retrofit conversions of
cross-functional project team together existing two-stroke engines to
with Eltronic FuelTech (fuel supply ammonia, preferably accommodating
systems), Technical University of the vessels’ five-year docking
Denmark and the classification society schedules after Q1 2025.
DNV GL.
As an important step towards a
carbon-neutral economy, MAN ES has
joined forces with important players on
the market in the launch of the Maersk
Mc-Kinney Moller Center for Zero
Carbon Shipping in Copenhagen. The
combined global and cross-disciplinary
effort will take us one step closer to the
research required to highlight
decarbonisation pathways. - Research,
which can guide and accelerate the
development of carefully selected
decarbonising fuels. Furthermore, the
global teamwork will support the
establishment of vital regulatory,
financial and commercial means to
enable the transformation.
The future will see cleaner fuels, and
the two-stroke engine technology will
likely remain the prime propulsion
motor for deep-sea shipping. Our
engine portfolio shows that the MAN
B&W two-stroke engines combust
various fuel types. MAN B&W ME-C
engines are based on future-proof
technology that already can be
retrofitted to run on LNG, LPG, ethane
and methanol as fuel. The development
of an engine type for ammonia
supplements our extensive dual-fuel
portfolio with an engine that will meet15
6. Bibliography
[1] https://innovationsfonden.dk/da/
investeringer/investeringshistorier/
dansk-konsortium-ledet-af-man-en-
ergy-solutions-vil-udvikle
[2] https://zerocarbonshipping.com/
[3] ALFA LAVAL, HAFNIA, HALDOR
TOPSOE, VESTAS, SIEMENS
GAMESA: Ammonfuel – an
industrial view of ammonia as a
marine fuel, August 2020
[4] Efficiency of Ships, IMO, www.imo.
org/en/OurWork/Environment/Pollu-
tionPrevention/AirPollution/Pages/
Technical-and-Operational-Mea-
sures.aspx, 2004
[5] MAN B&W ME-LGIP dual-fuel
engines, 5510-0210-00, MAN
Energy Solutions, 201816 MAN Energy Solutions
MAN B&W two-stroke engine operating on ammonia
7. Acronyms and abbreviations
CCS Carbon capture and storage
EEDI Energy efficiency design index
EEOI Energy-efficiency operational indicator
EGR Exhaust gas recirculation
FSS Fuel supply system
FVT Fuel valve train
GHG Greenhouse gas
GI Gas injection
GWP Global warming potential
HC Hydrocarbon
IMO International Maritime Organization
LCV Lower calorific values
LGI Liquid gas injection
LGIM Liquid gas injection methanol
LGIP Liquid gas injection propane
LNG Liquefied natural gas
LPG Liquefied petroleum gas
MGO Marine gas oil
NG Natural gas
RCC Research Centre Copenhagen
SCR Selective catalytic reduction
VLSFO Very-low-sulphur fuel oil17
MAN Energy Solutions
2450 Copenhagen SV, Denmark
P +45 33 85 11 00
F +45 33 85 10 30
info-cph@man-es.com
www.man-es.com
All data provided in this document is non-binding.
This data serves informational purposes only and
is not guaranteed in any way. Depending on the
subsequent specific individual projects, the
relevant data may be subject to changes and will
be assessed and determined individually for each
project. This will depend on the particular
characteristics of each individual project,
especially specific site and operational conditions.
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