Reducing NOx and SOx - Maritime Symposium Rotterdammaritimesymposium-rotterdam.nl/uploads/Route/Emission Reduction.pdf · 3.4 Effects on man-made materials ... 4. What are the options

REDUCING NOX AND SOX A summary of options

Rotterdam Mainport University MAROF - 2017

Wessel Pluim Kaj vd Valk

Niels Prinsen Wouter Fontijn

Date of issue: 31-01-2017

Project managers: Mr. van Kluijven Mrs. van der Drift

Project 2 – No sea too high Research

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Management review

Backgrounds All members working on the project are students of the Rotterdam Mainport University of Applied

Sciences. The team consists out four Maritime Officer students. The students have basic knowledge

gained from their previous study and sailing the high seas.

This project is made to improve the vessel’s ability to reduce the SOx and NOx that the vessel emits.

Problem Definition The vessel Sten Bergen emits to much NOx and SOx.

Main question How can the NOx and SOx on the vessel Sten Bergen be reduced?

The objective Reduce the amount of emitted NOx and SOx, so the Sten Bergen complies with the (future) regulations.

Epitome This research is about the options for reducing SOx and NOx on the vessel Sten Bergen. The options which are compared to each other are, Spark ignited Heavy Fuel Oil, Turning Electricity into Gas, Plasma technology, Selective Catalytic Reduction, Hydride propulsion, Nuclear Power in Marine Propulsion, Dimethyl ether (DME), scrubbers and exhaust gas recirculation. When those options are compared, a conclusion is given about what the best option is. It is possible to reduce the SOx and NOx at best with the following options. Combining DME (Dimethyl ether) + SCR (Selective Catalytic Reduction) will give no SOx emission and reduces NOx emission with 80%. The other option is Nuclear Propulsion. This will reduce the emission of SOx and NOx completely.


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Preface This research is written to see what kind of system the best option is for reducing NOx and SOx emissions

on the vessel Sten Bergen. Also, this research is part of our education in order to learn about doing

research, working as a team and learning about the different type of propulsion systems. This research

has been assigned to us, because of our preferences to educate about the technical sector in the

maritime industry. This research is given by the shipping company of the Sten Bergen. The research

compares existing researches which are about reducing NOx and SOx.

We would like to thank our supervisor Mr. van Kluijven and Mrs. Van der Drift for guidance and support.

Furthermore, we would like to thank all the experts for providing us with great feedback and

information.

Special thanks goes to the existing symposiums of the Mainport University of Rotterdam which provided

us with many information.


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Table of contents Management review ..................................................................................................................................... 1

Backgrounds .............................................................................................................................................. 1

Problem Definition .................................................................................................................................... 1

Main question ........................................................................................................................................... 1

The objective ............................................................................................................................................. 1

Epitome ..................................................................................................................................................... 1

Preface ........................................................................................................................................................... 2

1 Introduction ........................................................................................................................................... 5

1.1 Problem description ...................................................................................................................... 5

1.2 Problem definition ......................................................................................................................... 5

1.3 Main question................................................................................................................................ 5

1.4 The objective ................................................................................................................................. 5

1.5 Sub-questions ................................................................................................................................ 5

2 Legislation .............................................................................................................................................. 7

2.1 MARPOL (international) ................................................................................................................ 7

2.2 North-America ............................................................................................................................... 8

2.2.1 The United States .................................................................................................................. 8

2.2.2 Canada ................................................................................................................................... 8

3 SOx ....................................................................................................................................................... 10

3.1 Sulphur inside a fuel .................................................................................................................... 10

3.2 From Sulphur to Acid rain ............................................................................................................ 11

3.3 Effect on ecosystems ................................................................................................................... 11

3.4 Effects on man-made materials .................................................................................................. 12

4 NOx ...................................................................................................................................................... 13

4.1 Origin ........................................................................................................................................... 13

5 Possible options ................................................................................................................................... 14

5.1 How to reduce SOx ...................................................................................................................... 14

5.2 How to reduce NOx ..................................................................................................................... 14

5.3 Possible options ........................................................................................................................... 14

5.3.1 Spark ignited heavy fuel oil ................................................................................................. 14

5.3.2 Turning Electricity into gas .................................................................................................. 16

5.3.3 Plasma Technology and emission reduction ....................................................................... 17


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5.3.4 Selective Catalytic Reduction .............................................................................................. 18

5.3.5 Hybrid propulsion ................................................................................................................ 19

5.3.6 Nuclear Power in Marine Propulsion .................................................................................. 20

5.3.7 Dimethyl ether (DME) ......................................................................................................... 21

5.3.8 Scrubber .............................................................................................................................. 22

5.3.9 Exhaust gas Recirculation .................................................................................................... 23

6 Conclusion ........................................................................................................................................... 25

7 Recommendations............................................................................................................................... 26

8 Epilogue ............................................................................................................................................... 27

9 List of literature ................................................................................................................................... 28

10 List of Figures ................................................................................................................................... 30

11 List of tables..................................................................................................................................... 30

12 Glossary ........................................................................................................................................... 31

13 Appendix ............................................................................................................................................ 0

13.1 Decision matrix .............................................................................................................................. 0


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1 Introduction Since the beginning of the industrial revolution, mankind has the problem of SOx and NOx emitted from

the factories. These emissions were a big problem for the farmers and the workers in the factory. This is

solved for the factories. However, the merchant navy is still struggling with this problem, including the

company that possesses the Sten Bergen. That is why this research is made: to find a solution to the SOx

and NOx problem.

1.1 Problem description The Sten Bergen travels a lot between the U.S. and Europe, both have regulations concerning NOx and SOx emissions, both in their ports and in their ECA. These regulations are about the amount of emissions that the vessel is allowed to produce. In all of these ECA and ports the vessel has to comply with the regulations. Many vessels do not have a decent system on board to reduce these emissions, they must change over heavy fuel oil to gas oil. Changing over to gas oil is expensive and when changing over goes wrong, the vessel will lose her propulsion. The owner of the Sten Bergen wants to research the possibilities to reduce the emission of Sulphur and Nitrous oxides. SOx are formed when sulphur molecules react with oxygen. The sulphur is present in crude oil, and for that reason also in ship’s fuels. There is a certain amount of sulphur in the fuel. This sulphur will react with the oxygen in the engine. SOx is the main cause of acid rain. NOX emission can cause serious health problems, in the UK alone, thousands of people die from this emission every year. The following factors are necessary to form NOx in the diesel engine.

1. Sufficient oxygen available for the reaction 2. Sufficient temperature, this should be higher than 1200°C to form NOx 3. Enough time to form the NOx

Soon, legislations will get stricter regarding SOx and NOx. Therefore, the Sten Bergen needs a proper solution to comply with the regulations in an economic and safe way.

1.2 Problem definition The vessel Sten Bergen emits too much NOx and SOx.

1.3 Main question How can the NOx and SOx on the vessel Sten Bergen be reduced?

1.4 The objective Reduce the amount of emitted NOx and SOx, so the Sten Bergen complies with the (future) regulations

1.5 Sub-questions 1. What are the regulations regarding NOx and SOx? 2. What causes the SOx? 3. What causes the NOx? 4. What are the options for reducing NOx and SOx?


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These sub-questions are answered the same way as they are order here above. The legislation part is

about the legislation of North-America and Europe. The SOx part is about how they formed and what

damage they do. The NOx part is made up the same way as the SOx part. In the fifth chapter are all

the solutions explained with the specific rating. The weighted average of these solutions will be in

the appendix. In the conclusion and the recommendations are the answers for the main question:

how can SOx and NOx be reduced on the Sten Bergen.


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2 Legislation

2.1 MARPOL (international) MARPOL is the environmental part of the IMO legislation. All laws regarding: oil, chemicals, sewage,

garbage and emissions are listed in here. Laws regarding emissions are listed in annex VI of MARPOL.

Ships must comply with the maximum amount of sulphur dioxide they produce. sulphur amount inside a

fuel is being expressed as a percentage per ton. This means that if the sulphur amount of a fuel is

3,50%/ton, that for every ton of fuel there is 35 kilograms of sulphur dioxide mixed into it. Right now, the

maximum amount of sulphur dioxide in the SECA areas is 0,10%/ton. The maximum amount of sulphur

dioxide outside of the SECA areas is 3,50%/ton. In 2020 will the maximum amount outside the SECA area

decrease to 0,50%/ton.

Ships must also comply with the maximum nitrogen dioxide regulations of MARPOL. The quantity of NOx

is measured in gram per kilowatt-hour (g/kWh). This is because nitrogen is not originally in the fuel, but it

is in the air. Nitrogen dioxide is created inside the combustion chamber while the fuel is getting ignited.

More about this in the next chapter.

There is a tier system that will order all the ships to their specific maximum emitted NOx amount. The

variable that determines what tier the ship is in is the construction date of the ship or more specifically

the engine. After that the emission limit will be determined based on the engine’s rated speed (rpm).

Tier

Ship

construction

date on or after

Total weighted cycle emission limit (g/kWh)

n = engine’s rated speed (rpm)

n < 130 n = 130 - 1999 n ≥ 2000

I 1 January 2000 17.0 45·n(-0.2)

e.g., 720 RPM – 12.1 9.8

II 1 January 2011 14.4 44·n(-0.23)

e.g., 720 RPM – 9.7 7.7

III 1 January 2016* 3.4 9·n(-0.2)

e.g., 720 RPM – 2.4 2.0

Table 1 – MARPOL tiers

Tier III only counts when the ship is built after 1 January 2016 and is being located inside the North-

America emission control area. If the ship is not being in the North-America emission control area, it

must comply with tier II. (IMO, sd)


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2.2 North-America

2.2.1 The United States The United States has its own legislations. The is called the Act to Prevent Pollution from Ships or APPS

for short. The standard limits of MARPOL are adopted in this legislation.

The APPS is enforced in the coastal area of United states.

2.2.2 Canada Canada has its own legislation about emission control. This legislation is called Vessel Pollution and

Dangerous Chemicals Regulations. The standard limits of MARPOL are adopted in the legislation.

Both The coast of the United States and the coast of Canada have their own emission control area that is

Europe

Europe has two emission control areas, one is for the Baltic sea and the other is for the North Sea. These

areas only control the amount of sulphur dioxide that is being emitted. The port areas of member states

also have a sulphur dioxide emission control area. That means that they have same regulations about the

sulphur dioxide emissions as in the SECA areas.

Figure 1 - North American ECA


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A map of the North Sea and Baltic sea SECA area can be found. The northern border is placed at 62°

north latitude, the north-west border is placed at 4° west longitude and the south west border is placed

at 5° west longitude. (News, sd)


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3 SOx

3.1 Sulphur inside a fuel All products that are used as marine fuel, originate from crude oil. Crude oil is found around the world,

and is the fossil fuel that is most commonly used around the world. The amount of Sulphur in crude oil

varies around 0.5% to 6%, crude oil is defined as sour when the content of Sulphur is more than 0.5%

and sweet when it is below 0.5%. The most sought after oil is the sweet crude oil, this oil enables the

refineries to produce low sulphur fuels without too many problems, the crude oil with the higher Sulphur

content needs more processing to have fuel with the proper specifications. This will up the cost of the

fuel.

The crude oil is pumped from the ground in various areas around the world, the crude oil is then

transported to refineries. These refineries will produce fuel products by means of distillation. By

distillation the crude oil is divided in different fractions, by distillation various components with different

boiling points are evaporated and condensates in an ongoing process. (pollution, sd)

The fuels needed are the heavy fuel oils,

these HFOs are literally at the bottom of

the plant, they have a higher boiling point

then the rest of the product, this is also the

reason they are called residual oils.

The HFO consists of long Hydrocarbon

chains. The residual oil gets more refining

then described above. It needs to meet the

IMO specifications. The viscosity and other

component needs to be within limits, now

to the Sulphur part. Most of the Sulphur

stays in the bottom of the plant, the

Sulphur needs to get out of the fuel to

meet the IMO specifications.

In Europe, the most commonly used

desulphurization method is hydrocracking,

by injecting hydrogen under high pressure,

the Sulphur elements are "broken" of from

the hydrocarbon chains and turned into

Hydrogen sulphide (H2S).

Figure 2 - Processing of crude oil


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3.2 From Sulphur to Acid rain Sulphur is becoming a problem when the fuel is ignited in the combustion chamber. Due to a chemical reaction between Sulphur and Oxygen, Sulphur dioxide (SO2) is formed. Acid rain is formed due to a chemical reaction of Hydrogen Peroxide and Sulphur dioxide in clouds. The rain which is formed is called Sulfuric acid. (Acid Rain - Causes, Effects and Control) Acid rain is having effect on multiple aspects (United States Environmental Protection Agency, 2008).

- Effects of acid rain on ecosystems

- Effects of acid rain on man-made materials

3.3 Effect on ecosystems “An ecosystem is all the living and non-living things in an area, as well as interaction between them.”

(United States Environmental Protection Agency, 2008)

3.3.1.1 Forests

Acid rain causes significant damage to forests. It directly affects trees and other plants which are

important to the ecosystem as a whole, because they are primary producers.

Primary producers are organisms that produce their own food through photosynthesis.

This acid causes trees in forests to grow more slowly, and for some sensitive species, it can even make

the leaves or needles turn brown and fall off.


3.3.1.1.1 Forest floor

The rain damages trees by dissolving the calcium in the soil and in the leaves of trees. This hurts the tree,

because calcium Is a mineral that trees need to grow. Once the calcium is dissolved, the rain washes it

away so the trees and other plants cannot use it to grow.

A spring shower in the forest washes leaves and the rain falls through the trees to the forest floor below.

Some of the water soaks into the soil. Some trickles over the ground and runs into a stream, river, or

lake.

Soil sometimes contains substances, like limestone, that buffer acids or bases. Some salts in soil may also

act as buffers. The soil may neutralize, or make less acidic, the acid rainwater. This ability of the soil to

resist pH change is called a buffering capacity. A buffer resists changes in pH. Without buffering capacity,

Figure 3 Formation of acid rain Source: (United States Environmental Protection Agency, 2008)


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soil pH would change rapidly.


3.4 Effects on man-made materials Acid rain eats away at stone, metal, paint and almost any other material exposed to the weather for a long period of time. Human-made materials gradually deteriorate even when exposed to unpolluted rain. But acid speeds up the process. Acid can rust metals and cause marble statues carved long time ago to lose their features. Many monuments and buildings are made of marble and limestone, which consists of calcium carbonate. Calcium carbonate can be dissolved by acids. (United States Environmental Protection Agency, 2008)


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4 NOx

4.1 Origin NOx is the result of a chemical reaction inside the combustion chamber. The intake air consists mostly

out of nitrogen (N2) and oxygen (O2). These two gases will react with each other in certain

circumstances.

N_2+O_2=2NO

These circumstances are:

- There must be sufficient oxygen. This will always be the case with marine diesel engines, because

there will always an overload of air being brought in the cylinders.

- The right temperature. This will also be the case with marine diesel engines. The temperatures in

the cylinders exceed levels of 1400 °C.

- There must be enough time for the reaction to happen. Bigger engines that have a slow rotation

speed, may have bigger emissions of NOx than faster running engines, because the reaction has

more time to happen in slower engines.

NOx is a serious problem regarding health and environment. When NOx interacts with sunlight it will

create smog. Smog reduces visibility and is dangerous for health reasons. NOx can irritant the eyes and

nose and giving breathing problems. It can also cause cancer and heart attacks. There are 50.000

premature deaths because of air pollution of ships1.

NOx is also the cause of more damage like: killing biodiversity in ecosystems and depleting the ozone

layer.

To stop these reactions from happening it will be necessary to lower the temperature in the cylinders, or

by another way.

(Maanen), (international, 2014)

1 Air pollution from ships - https://www.transportenvironment.org/what-we-do/shipping/air-pollution-ships

https://www.transportenvironment.org/what-we-do/shipping/air-pollution-ships


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5 Possible options

5.1 How to reduce SOx As read in the previous chapter, the source of the sulphur in the SOx is coming from the fuel. One way to

reduce SOx is by using clean fuel like LNG. Another way of reducing SOx is by cleaning the exhaust

gasses.

5.2 How to reduce NOx As read in the previous chapter, the main cause of NOx is a high temperature in the cylinder that causes

the reaction of oxygen and nitrogen. One way of reducing NOx is by reducing those temperatures in the

cylinders. Another way is by cleaning the exhaust gasses.

Cleaning the exhaust gasses requires most of the time another expensive system on the ship, however it

is possible to both reduce SOx and NOx with just one solution. It is also possible to have a combination of

two solutions.

5.3 Possible options Each option will be rated on several subjects. These subjects are:

- The ability to reduce SOx. - The ability to reduce NOx.

- The size of the system or medium. - The difficulty for installation.

- How much waste it generates. - If any other problems that acts as barriers.

The scores are from 0 to 5, where 0 is really bad and 5 is really good. These number are added up to a total score. The options with the highest scores will be taken to the conclusion and recommendation.

5.3.1 Spark ignited heavy fuel oil Spark ignited heavy fuel oil will increase efficiency

by replacing the compression stroke by a “non-

compression-stroke”. This is good because the

compression-stroke uses a lot of the generated

energy by the work-stroke. But now there is not

enough air to have a proper combustion and the

fuel won’t be ignited by the high temperatures

generated by the compression-stroke. A

turbocharger will insert the required amount of air

in the cylinder right before the top end of the

stroke. The inlet valve will open to let the air into

the cylinder. The required temperature can be

solved in two ways. Figure 4 - Spark ignited HFO


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- A laser plug can be used to ignite the

fuel mixture. This is only possible with

MDO.

- A pilot fuel like LNG will be used to

create a flame in a pre-chamber to

ignite the fuel mixture. This is also

possible with HFO.

Solution 1 can be used in combination with the

low sulphur fuel MDO to comply. Solution 2 can

be used with a cheaper fuel, but this fuel

contains likely too much sulphur. So, solution 2

can only be used in combination with an

exhaust gas cleaner. (Spark ignited heavy fuel

oil and marine diesel oil)

5.3.1.1 Effectiveness reducing SOx

This option is not for reducing SOx, but for increasing efficiency and reducing NOx. A cleaner fuel like

MDO or LNG should be used in combination with this option to reduce SOx. Because it is not reducing

SOx it will score 1 point. (Spark ignited heavy fuel oil and marine diesel oil)

5.3.1.2 Effectiveness reducing NOx

Air will not be compressed with this method, so temperatures that were created by this compression will

be much lower. The overall temperatures in the cylinder will also be lower because of this. Less NOx is

formed because of these lower temperatures. Further research is necessary to know how much the

temperatures will be lowered, and thus know how much the NOx will be reduced. It scores 3 points,

because it does reduce NOx, but it is unknown how much. (Spark ignited heavy fuel oil and marine diesel

oil)

5.3.1.3 Size

The extent of these upgrade is small and therefore the extra weight also. This upgrade requires a change

in the cylinder heads of the engine and an extra tank for the pilot fuel for solution 2. It scores 4 points,

because the size is small but it still requires room for the pilot fuel tank. (Spark ignited heavy fuel oil and

marine diesel oil)

5.3.1.4 Ease to install

The installation consists of an upgrade to the engine. The cylinder head are being replaced by the

upgraded ones. The camshaft needs an upgrade to change the timing of the valves and the injection.

Also, a turbocharger needs to be placed instead of the normal turbo. Because these upgrades are only

being applied on the engine, it will score 4 points. (Turning Electricity Into Gas)

5.3.1.5 Waste generation

The only waste generated with this option are the broken parts. This option scores 5 points, because of

very small waste generation. (Spark ignited heavy fuel oil and marine diesel oil)

5.3.1.6 Miscellaneous problems

This option has not been tested yet. This may be a problem, because of unexpected results. Further

research is necessary, so it will score 2 points. (Spark ignited heavy fuel oil and marine diesel oil)

Figure 5 - Spark ignition


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5.3.2 Turning Electricity into gas This option is based on making methane gas by producing hydrogen and let it react with the CO2 of the

exhaust gasses. Hydrogen will be made by a chemical process called electrolyse. The electricity that will

be used is generated by green methods. This process will use electricity to separate the hydrogen

molecule of the oxygen one.

2H_2 O→2H_2+O_2

The hydrogen molecule will later be added to the carbon dioxide one to make methane gas and water.

CO_2+4H_2→CH_4+H_2 O

This methane gas can be used as fuel for the engines. This gas does not contain sulphur, so it will not

produce any SOx. According to the research It also complies with tier III of the NOx legislation.

All research points of this paragraph are referred to (Turning Electricity Into Gas).


The methane gas does not contain any sulphur, so there will not be any SOx produced. It scores 5 points

because of this.


This option makes the ship comply with tier III of the NOx legislation. However, it does not say how. The

engine will still have high combustion temperatures, also with gas. Further research necessary to find

out. It scores 2 points.

5.3.2.3 Size

The gas will probably be made on shore by a surplus of electricity, according the recommendation

section of the report. This gas is used only for the North-Amerika ECA area. However, the ship cannot

rely on shore based equipment for this research, so the gas production must be on board. All the

electricity must be produced by “green” methods. Solar panels and wind turbines can be used as

options. 4,3 kilowatt-hour of electricity is needed to obtain one kilowatt-hour of thrust. 81,7 square

meters of solar panels is needed to produce 4,3 kilowatt-hours. This is roughly the size of a square with

the size nine by nine meters. This means that a tremendous and unrealistic number of solar panels is

needed to power the hydrogen plant and main engine. Also with wind turbines this is not realistic.

Therefor it scores 0 points. (Spark ignited heavy fuel oil and marine diesel oil)


The ship needs to be retrofitted. The ship needs a hydrogen plant that makes hydrogen and methane of

the produced electricity. The ship needs a storage tank of the produced methane. Also, all the solar

panels and wind turbines should be fitted. This is an enormous job and probably not the effort. Therefor

it scores 1 point. (Spark ignited heavy fuel oil and marine diesel oil)


This option is completely “green”. All the electricity produced on board is done by “green” methods.

Methane is a very clean fuel that only emits CO2 and water vapour. The hydrogen plant can even recycle


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the CO2 in the exhaust gas. Because this method is very green it will score 5 points. (Spark ignited heavy

fuel oil and marine diesel oil)


The recommendation section of the report says that it is more likely to create methane on land and

deliver it to the ships. Hydrogen on board is always very dangerous. The amount of power needed to

create the methane is also a big problem and probably not worth it. It scores 0 points. (Spermon)

5.3.3 Plasma Technology and emission reduction Matter can be: solid, liquid or a gas. But after gas is another state. This state

is plasma and can be reached by heating a gas to very high temperatures.

The electrons will free themselves from their atom shells and float around.

The electrical characteristics will change, because of this ionization. This

ionization will break the NOx molecules, and thus lowering the NOx

emissions. These high temperatures are reach by converting 400 volts to 10

kilo volts and zapping it through the exhaust gasses 1000 times a second.

All research points of this paragraph are referred to (Mulders).


This option does not remove SOx. It scores 0 points.


This method will reduce 90% of the NOx in the air, like the SCR system. This

system still requires a lot of energy to remove the NOx. It scores 4 points.

5.3.3.3 Size

The system requires a plasma reactor and a catalyst. The size of these two components can be compared

with the size of an exhaust gas cleaner. The system also needs a generator that supplies the power to the

plasma plant. This can be a ships generator. It scores 3 points.


This system can be installed on existing ships. The funnel is the best place for the system. It scores 3

points.


This method does not generate any waste. It scores 5 points.


High fuel demand is the cause of the high voltage requirement, it is unknown how much power the

system needs. Because of this it scores 3 points. (Mulders)

Figure 6 - Plasma technology


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5.3.4 Selective Catalytic Reduction Selective Catalytic Reduction or SCR is a way of cleaning the exhaust gasses by making it react to

ammonia. This will break the NOx molecules back to nitrogen.

NO+NO2+2NH3→2N2+3H2O

The NOx will break into nitrogen and water after the reaction. Nitrogen and water are not harmful for

the environment. However ammonia is a very toxic and corrosive substance. Therefor it is possible to use

urea that is less dangerous and corrosive. Urea must be converted to ammonia at high temperatures in a

hydrolysis catalyser.

All research points of this paragraph are referred to (Boot).


This method does not include

cleaning SOx. The SCR system is not

able to eliminate SOx in the system. A

combination of another system is

needed to comply with these

legislation, or a low sulphur fuel

should be used. So it scores 0 points.


The SCR makes the ship comply with

the tier III regulations. It needs an

additive to clean it. This additive needs its own storage tank. The system will always work when the

additive is added. Because the system needs an additive it will score 4 points.

5.3.4.3 Size

The system is roughly the size of a muffler that is used to decrease vibration of the exhaust. It is

therefore possible to replace this muffler with an ECR system. This is done multiple times with other

ships. The urea tank only requires a volume of around 40 litres. The system is only active in the ECA.

Because the system can replace the muffler and the tank is not big it will score 3 points.


The system is not too difficult to install. The system can be replaced with the muffler on the exhaust. This

method has been done before on previous ships. It scores 4 points.


No waste is generated with this method. However the additive urea is a toxic substance. It may be

possible that this may pollute the environment if it spills. It scores 5 points.


The system is reliable on specific temperatures of the exhaust gasses. The engine should not run on a

low load for a long time. This can clog up the system because of condensation of certain gasses. The

chemical process will not work if the temperatures are too high. This can be solved to stop adding urea if

the temperatures are too low or high. The ship should run on the same load as much as possible. It

scores 4 points. (Boot)

Figure 7 - SCR schematic


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5.3.5 Hybrid propulsion Hybrid propulsion is a method that is based on storing power for later to use in the ECA. The power is

generated when the ship is sailing on the ocean and stored in batteries. The ship will stop the main

engine and continue sailing on the stored power when entering the ECA. The power is generated on the

ocean using the shaft generator. The engine does not emit any exhaust gasses when using the stored

power, because it does not run. The ship complies to the ECA and SECA legislation, because of this.

All research points of this paragraph are referred to (e.a. A. M.).


The ship is able to completely stop the SOx emissions while sailing in the ECA and SECA. However, the

ship still uses the main engine on the ocean. Here it still has its full SOx emissions and it will not be

reduced without another way. The SOx limit on the ocean right now is 3,5%, but in 2020 it is 0,5%. This

means that it requires fuel with a maximum sulphur amount of 0,5%. The ship does not need to use the

expensive gasoil with a sufficient amount of sulphur, but still needs a low sulphur fuel. It scores 2 points.


The ship’s main engine does not run in the ECAs. This means that all kinds of exhaust gasses are not

emitted while sailing in these ECAs. These means that any kind of NOx will not enter the atmosphere. On

the ocean, it still does emit NOx. It scores 4 points.

5.3.5.3 Size

The vessel requires a set of equipment to use this method of propulsion. These are:

- A shaft generator/motor to generate the electricity on the ocean, and can be used to power the

propeller (power take in and power take off).

- High capacity batteries to store the energy for the ECAs.

If the is already fitted with a shaft generator, then this one should be upgrades to also power the

propeller. It is unknown what kind of shaft generator is installed on the Sten Bergen. It is not too difficult

to upgrade it but also not easy, so it scores 3 points.


The vessel requires a moderate overhaul to install the system. The shaft generator needs to be upgraded

and a set of high capacity batteries needs to be placed. Again, it is not too hard to install the system but

also not very easy, so it scores 3 points.


The system does not generate any waste while operated. It scores 5 points.


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The amount of work the batteries need to supply is a lot. The time the vessel is in the ECA (200 nm) with

a speed of 12 knots is around 17 hours. If the engine is supplying 8000 kW of power to the propeller it

would have created around 140000 kWh of work. The batteries also need to supply enough power to

supply the shaft generator. This is done by creating a very high voltage to decrease the capacity needed

for the batteries. The highest voltage that can be created on board is 10 kV. The amount of current

needed is done by dividing the power needed by the voltage. The answer is that the batteries need to

supply 800 amperes at a voltage of 10 kV. The capacity is the current times the time needed to stay in

the ECA. This is 13600 Ah and that is a lot. Further research is necessary to find out how big and how

many batteries are needed for the ship. It scores 1 point. (e.a. A. M.)

5.3.6 Nuclear Power in Marine Propulsion Nuclear marine propulsion is a ship propulsion using a nuclear reactor, it has been used on battle ships

for several years. But only a few nuclear merchant ships were built as an experiment. The nuclear system

that is used on vessels is called a high-pressure reactor (155 bar). In this type of reactor, the reactor

delivers heat to make the water boil and the steam of this boiled water will drive the steam turbine.

With one nuclear reactor, can generate a total power of 25.000 KW. With one reactor load, this means a

reactor fully filled with fuel bundles of enriched uranium, can sail about 350.000 nautical mile.

All research points of this paragraph are referred to (Ligtvoet).


The effectiveness of reducing SOx with a nuclear reaction is very good. This is because there is no

combustion of SOx when the nuclear reaction is in use. This is because the power is generated by

pressurised steam. It scores 5 points


The effectiveness of reducing NOx is the same as SOx. There is no combustion of NOx during the use of

this nuclear reaction. Because the power is generated by pressurised steam. It scores 5 points.

5.3.6.3 Size

There is already an existing nuclear power system for on-board of merchant vessels; this system is called

the “HPM (Hyperion Power

Module)”. The size of this

system are 1,5 meters in

diameter and a height of 2,5

meters. As can be seen in the

picture below the HPM is

just a part of the total

installation. This is a

proximately the size of the

main engine. It scores 4

points. Figure 8 - Nuclear propulsion schematic


21 Project group 1


As can be seen in the picture below the HPM is just a part of the total installation. On-board this should

not be a problem. Most of the other components are already in use at nowadays combustion based

vessels. This picture gives the application of the Hyperion Power Module on land. There the nuclear

reactor will be fit in a so-called reactor vault. This is placed under the ground. On-board a vessel this is

impossible of course. When applied on a vessel it won’t be exactly as this picture shows but it gives a

good short overview of the system which is necessary for propulsion on board. The whole engine room

must be changed. It scores 2 points.


When the reactor has lost its power, the core must be renewed. The old core is still sending out nuclear

radiation. It takes years before the nuclear waste has lost its strength and won’t send out dangerous

radiation anymore. The waste is still difficult to handle, so it scores 1 point.


Furthermore, there are some miscellaneous problems with a nuclear system. Because of the disasters

that happened on land with nuclear power plants in the past, people are afraid that this could also

happen at sea. and that it will be a danger when ships collide or hit a reef, in that case the sea water will

get exposed to radioactive material. Also, a human error is a risk what can occur. When entering some

harbours, it is possible that they don’t accept the waste generation of the nuclear system. What also a

serious miscellaneous problem can be with a nuclear system is the high installation costs. Engineers

should be trained to work with the reactor. It scores 1 point. (Ligtvoet)

5.3.7 Dimethyl ether (DME) DME is a new kind of biofuel that will reduce SOx and NOx. DME is a gas that is easily handled. Unlike

other gasses DME does not need cooling. It is not less safe than other fuels like MDO and HFO which

make is. DME is used as propellant for deodorant.

All research points of this paragraph are referred to the (e.a. A. v., 2013).


Just like LNG, DME does not contain any sulphur. This makes the reduction of SOx 100%. It scores 5

points.


The fuel creates just like any other fuels high temperature in the cylinders. The fuel itself is not effective

against NOx. It scores 0 points.

5.3.7.3 Size

The fuel can be used on modern diesel engines. All the existing piping can be used for the fuel. It scores 5

points.


The vessel needs a few modifications before it can use DME. DME has bad lubrication qualities, therefore

the engine requires additional machinery to lubricate the fuel pump separately. The fuel tanks also need


22 Project group 1

small modification to store the DME. The total amount of modification needed are low and easy to

install. It scores 5 points.


DME does not generate any waste while used. It scores 5 points.


The Inner energy output of DME is lower than MDO and HFO. The inner energy output lies around

28MJ/kg, MDO and HFO are around 40 MJ/kg. This is about 30% lower. More DME must be burned to

get the same power output. Still this should not be a huge problem, since other solutions may solve this.

It scores 4 points. (e.a. A. v., 2013)

5.3.8 Scrubber In the main scrubbing process, the first

stage is to cool the exhaust gas which

is up to 350°C down to 160-180°C in an

exhaust gas economiser (optional) as

opposed to just wasting the heat.

In the second stage, the exhaust gas is

treated in a special ejector where it is

further cooled by injection of water

and where much of the soot particles

in the exhaust gas will be removed.

In the third stage, the exhaust gas is

led through an absorption duct where

it is sprayed with water and thus

cleaned of the remaining Sulphur

dioxide.

These exhaust gas cleaning systems

can be broadly divided into two types:

wet and dry. Wet scrubber systems

use seawater or freshwater in combination with chemical additives such as NaOH - or the scrubber may

be able to operate in both modes. For marine use, wet scrubbers are so far dominating the market.

(COWI, 2012)


The main objective of scrubber operation is washing out sulphur, but also significant amounts of particle

mass is trapped. Multiple studies show that a Scrubber system will wash away around 90% of SOx.

(E. den Boer, 2015)


The scrubber technology does not remove nitrogen oxides or only to a very small degree. Maximum 10%

NOx reduction. (E. den Boer, 2015)

Figure 9 - Scrubber Schematic Source: (COWI, 2012)


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5.3.8.3 Size

Scrubbers have the advantage, to be medium sized and fit inside a vessels funnel.


Because of the medium sized shape, which could easily be retrofitted on older vessels, it would be an

optional possibility.

Scrubbers are installed in the ships funnel.


The wash water of the scrubber produces waste that will be put overboard. This waste can be treated

with a wash water treatment plant. The scrubber also produces sludge. This sludge has to be treated

with separator to separate to water out of it. The water can be set overboard or hold on board. Future

legislation may prevent dumping this waste in the ocean. It scores 3 points. (E. den Boer, 2015) (COWI,

2012)


Problems could occur during the disposal of the scrubber’s sludge. Sludge tanks can run full when a port

is not regularly called.

5.3.9 Exhaust gas Recirculation A way to reduce the nitrogen oxide emissions of a diesel engine is the use of exhaust gas recirculation,

EGR. Here, a part of the exhaust gases is rerouted into the combustion chamber. This leads to a lower

peak combustion temperature which in turn reduces the formation of NOx.

This can be achieved either

internally with the proper valve

timing, or externally with piping.

The exhaust gas acts as an inert gas

in the combustion chamber, it does

not participate in the combustion

reaction. This leads to a reduction of

the combustion temperature by

different effects.

The fuel molecules need more time

to find an oxygen molecule to react

with, as there are inert molecules

around. This slows down the

combustion speed and thus reduces

the peak combustion temperature,

as the same amount of energy is released over a longer period of time. (Reifarth, 2010)


This system does not have any effect on the reduction of SOx

Figure 10 - Schematic drawing of EGR Source: (Kech, 2014)


24 Project group 1


NOx will be reduced between the 20 and the 30%. The rest of the NOx could be reduced using an

exhaust after treatment. Such as the SCR. (Rahhod, 2012)

5.3.9.3 Size

This system will not take too much space. The cooler and the piping along the cooler are considered as

the aspects which need to take care of.


The installation of such a system should be relative simple. Piping’s, heat exchanger, sensor, valves and a

soot filter should be installed, but do not underestimate.


The only waste which is generated during the EGR operation is more soot particles, which are filtered out

by a particulates filter. This filter need to be cleaned at a regular basis.


The system which requires to reduce the amount of oxygen inside the cylinder, has the side effect of

losing some of its engine power.

The deliberate reduction of the oxygen available in the cylinder will reduce the peak power available

from the engine. For this reason, the EGR is usually shut off when full power is demanded, so the EGR

approach to controlling NOx fails in this situation.

The EGR valve cannot respond instantly to changes in demand, and the exhaust gas takes time to flow

around the EGR circuit. (CamBustion, 2017)

While reducing the NOx with the EGR-system, more soot particles are formed. Which must subsequently

be filtered out by a particulates filter. During operation, the filter has to be regularly regenerated by

burning out the soot. (Trucks, 2015)


25 Project group 1

6 Conclusion SOx and NOx emissions are going to be a big problem for the future. Nations are making regulations to

prevent this from happening. This a problem for ship owners, because they should modify their ship in

order to comply. A lot of companies are designing new systems that will make it possible for the ships

comply.

SOx is caused by the sulphur elements in the fuels. This sulphur gets in the air by combustion. The easiest

way to prevent this is by removing the sulphur in the fuel.

NOx is much more difficult to remove from the exhaust gasses. NOx is created because of the high

temperatures in the cylinders. It is a real challenge to lower these temperatures. It is better to filter of

the NOx out of the exhaust gasses. This must be done with complex chemical processes.

The conclusion that will determine the best option is based on a score system. Each option was rated on

six different subjects. The options with the highest score is the winner. However, there are no options

that will cover both the reduction of SOx and NOx. This means that a combination of two options should

be made to cover both reductions. Except for nuclear energy. Nuclear energy is able to completely

remove SOx and NOx from the ship’s emissions.

The options listed in chapter six are reviewed in a decision matrix, based in their scores. This matrix can

be found in appendix 1 on page 32.


26 Project group 1

7 Recommendations Two recommendations are the result of this research. One recommendation is to have a combination of

two options to cover both the reduction of SOx and NOx. The other option will cover both with just one

solution.

1. According to this research, this recommendation is to use the new fuel DME in combination with

a Selective Catalytic Reduction. The DME does not contain sulphur, and the SCR reduces the

NOx.

2. The second option is to use nuclear power. Nuclear power is totally free from exhaust gasses.

The biggest problem is that it generates dangerous waste and that the reactor can cause severe

damage to the environment when a meltdown happens.

If DME is not available for use, the conventional MDO can also be used, because of its low sulphur

content. Further research to DME may be necessary.

Scrubbers may also be a good choice if HFO is required for the operation of the vessel.


27 Project group 1

8 Epilogue During this research, we have learned which new innovations are available on the maritime market and which innovation is the best option on board of reducing pollutant emissions. Reducing techniques like EGR, SCR, Scrubbers and Spark ignition are researched on its liability and DME and Nuclear propulsion are described. After a decision matrix, the best choice for the vessel would be a mix of the DME fuel with the SCR system, or Nuclear propulsion. Nuclear power reduces both NOx and SOx. Meanwhile DME is a well promising gaseous fuel, but only reduces the SOx by 100% and should be fitted together with a NOx reducer like the SCR-System which reduces the NOx with roughly 80%. Research is done by learning more about innovation of the future, like spark ignition and Nuclear power. Still further research should be done regarding spark ignition and Nuclear propulsion. The research itself went very well. The only problem which occurred was a project member leaving the project half way through. Teamwork was one of the strong points during this project. When the unfortunate event happened of a project member leaving the group, everyone was well prepared to divide his work along to other group members. Informing each other on the progress and helping each other was daily routine.


28 Project group 1

9 List of literature Boot, Q. (n.d.). Selective catalytic reduction. Retrieved from www.maritimesymposiumrotterdam.nl:

http://www.maritimesymposium-

rotterdam.nl/uploads/Route/Plasma%20Technology%20and%20emission%20reduction..pdf

CamBustion. (2017). Exhaust Gas Recirculation (EGR) and NOx measurement. Retrieved from

CamBustion: http://www.cambustion.com/products/egr

COWI. (2012). Assesment of possible impacts of scrubber water discharges on the marine environment.

kopenhagen: Danish Ministry of the Environment.

E. den Boer, M. '. (2015). Scrubbers - an economic and ecological assessment. Delft: CE Delft.

e.a., A. M. (n.d.). Hybrid propulsion. Retrieved from www.maritimesymposiumrotterdam.nl:

http://www.maritimesymposium-rotterdam.nl/uploads/Route/Hybrid%20propulsion.pdf

e.a., A. v. (2013, 4 16). Dimethyl ether. Retrieved from www.maritimesymposiumrotterdam.nl:

http://www.maritimesymposium-rotterdam.nl/uploads/Route/Dimethylether.pdf

e.a., M. M. (n.d.). Spark ignited heavy fuel oil and marine diesel oil. Retrieved from

www.maritimesymposiumrotterdam.nl: http://www.maritimesymposium-

rotterdam.nl/uploads/Route/SPARK%20IGNITED%20HFO%20AND%20MDO.pdf

IMO. (n.d.). Nitrogen Oxides (NOx) – Regulation 13. Retrieved from IMO.org:

http://www.imo.org/en/OurWork/environment/pollutionprevention/airpollution/pages/nitroge

n-oxides-(nox)-%E2%80%93-regulation-13.aspx

international, Y. (2014). NOx Reduction - SCR Systems and DeNOx Reagent for Ships. Retrieved from

https://www.youtube.com/watch?v=rpFyIYpfVg4

Kech, D. J. (2014). Exhaust Gas Recirculation: Internal engine technology for reducing nitrogen oxide

emissions. MTU Friedrichshafen GmbH.

Kulp, J. L. (n.d.). Acid Rain - Causes, Effects and Control.

Ligtvoet, S. (n.d.). Nuclear power in marine propulsion. Retrieved from


rotterdam.nl/uploads/Route/Nuclear%20power%20in%20marine%20propulsion.pdf

Maanen, P. v. (n.d.). Dieselmotoren en het milieu. In P. v. Maanen, Scheepsdieselmotoren (p. 2.12).

Mulders, R. (n.d.). Plasma technology and emission reduction. Retrieved from


rotterdam.nl/uploads/Route/Plasma%20Technology%20and%20emission%20reduction..pdf

News, P. (n.d.). High aims of low sulphur. Retrieved from portnews.ru:

http://en.portnews.ru/comments/1573/

pollution, C. (n.d.). Extraction of raw materials. Retrieved from Chemical pollution.com:

http://www.chemical-pollution.com/en/chemicals/production.php


29 Project group 1

Rahhod, D. P. (2012). Effect of exhaust gas Recirculation (EGR) on NOx emission from C.I. engine.

International Journal of advanced Engineering Research and Studies.

Reifarth, S. (2010). EGR-Systems for Diesel Engines. Stockholm: KTH Industrial Engineering and

Management.

Spermon, J. (n.d.). Turning Electricity Into Gas. Retrieved from www.maritimesymposiumrotterdam.nl:

http://www.maritimesymposium-

rotterdam.nl/uploads/Route/Turning%20electricity%20into%20gas.pdf

Trucks, N. (2015). SCR vs EGR - Which is the best technology. Retrieved from NI-trucks: http://www.ni-

trucks.co.uk/news/scr-vs-egr-which-is-the-best-technology

United States Environmental Protection Agency. (2008). Learning about acid rain. Washington: Clean air

markets Division.


30 Project group 1

10 List of Figures Figure 1 - North American ECA ...................................................................................................................... 8

Figure 2 - Processing of crude oil ................................................................................................................ 10

Figure 3 Formation of acid rain Source: (United States Environmental Protection Agency, 2008) ............ 11

Figure 4 - Spark ignited HFO ........................................................................................................................ 14

Figure 5 - Spark ignition ............................................................................................................................... 15

Figure 6 - Plasma technology ...................................................................................................................... 17

Figure 7 - SCR schematic ............................................................................................................................. 18

Figure 8 - Nuclear propulsion schematic ..................................................................................................... 20

Figure 9 - Scrubber Schematic Source: (COWI, 2012) ................................................................................. 22

Figure 10 - Schematic drawing of EGR Source: Ongeldige bron opgegeven. .............................................. 23

11 List of tables Table 1 – MARPOL tiers ................................................................................................................................. 7


31 Project group 1

12 Glossary SOx: Sulphur oxide NOx: Nitrogen oxide U.S.: United states ECA: Emission control area SECA: Sulphur emission control area MARPOL: International convention for the prevention of marine pollution IMO: International maritime organisation RPM: Revolutions per minute APPS: Act to prevent pollution for ships MDO: Marine diesel oil HFO: Heavy fuel oil LNG: Liquefied natural gas SCR: Selective catalytic reduction HPM: Hyperion power module DME: Dimethyl Ether

13 Appendix

13.1 Decision matrix

Documents

Reducing NOx and SOx - Maritime Symposium Rotterdammaritimesymposium-rotterdam.nl/uploads/Route/Emission Reduction.pdf · 3.4 Effects on man-made materials ... 4. What are the options