Comparing Wet and Dry Exhaust Gas Cleaning Systems

Transcription

Bachelor project
Aarhus School of Marine and Technical Engineering
2013
Comparing Wet and Dry Exhaust
Gas Cleaning Systems
By Ole Groulef Vestergaard
04-06-2013
Ole Groulef Vestergaard
Bachelor project
2013
Writer: Ole Groulef Vestergaard
Student number: A10049
Title: Comparing Wet and Dry Exhaust Gas Cleaning Systems
Project type: Bachelor project
Date of submission: 4th June 2013
Subject area: Marine Engineering, rules and regulations
Education: Bachelor of Technology Management and Marine Engineering (Maskinmester)
Year/Class: 6. Semester / Class E6 / 2013
Educational institution: Aarhus School of Marine and Technical Engineering
(Aarhus Maskinmesterskole)
Name of supervisor: Henrik Møller Nielsen
Standard pages: 40.4 (96902 characters including spaces)
Source of the picture on the front page:
01- 06 – 2013 - http://www.safety4sea.com/images/media/2011.6.6-emissions.jpg
Signature
1
Bachelor project
2013
Resumé
Baggrunden for dette projekt er udfærdigelse af et bachelorprojekt i forbindelse med
maskinmesteruddannelsen på Aarhus Maskinmesterskole. Emnet i projektet er ønsket af
Scandic Diesel Services i Montreal/Canada, hvor bachelorpraktikopholdet blev udført.
Dette projekt omhandler forskellen mellem et vådt og tørt afsvovlingsanlæg på skibe. Det
stillede hovedspørgsmål lagde op til en undersøgelse af, hvilken af de to systemer som er
den mest bæredygtige i forhold til at kunne overholde fremtidens miljøkrav. Projektet tager
udgangspunkt i de regler og reguleringer, som er opstillet i MARPOL Annex VI regulation
14, der regulerer svovludledningen fra skibsindustrien. Den næste vigtige dato angående
svovludledning er d. 1. januar 2015, hvor svovlindholdet i brændselsolien maximalt må
være 0,1 % inden for bestemte områder kaldet Emission Control Areas (ECA). Ang. NO X
udledning bliver der strammet op d. 1. januar 2016 ifølge TIER III. Dette sker, med mindre
en revision udfærdiget af IMO1 ændrer på dette. Bemærk at dette kun gælder for nye skibe
eller om konstruktioner.
Det tekniske aspekt er derefter undersøgt i forhold til at kunne sammenligne de to
systemer. Projektet har klargjort de væsentligste forskelle, som der er i mellem et vådt og
et tørt afsvovlingsanlæg på skibe. En af forskellene er opbygningen, hvor et tørt anlæg er
væsentligt tungere i forhold til et vådt anlæg. Samtidig gør konstruktionen, at det tørre
anlæg er placeret højere oppe i skibet, hvilket har en negativ indflydelse i forhold til
tyngdepunktet på skibet. En anden forskel er håndteringen af de førnævnte NO X krav, som
måske kommer i 2016. Grunden til det er, at en katalysator som reducerer NOX ikke kan
håndtere svovl i udstødningsgassen, og derfor skal katalysatoren placeres efter
afsvovlingsanlægget. Sammenlignet med et tørt afsvovlingsanlæg sænker et vådt anlæg
udstødningstemperaturen væsentligt. Dette gør, at monteringen af en katalysator til at
reducere NOX udledningen findes bedre egnet til et tørt anlæg grundet den høje
temperatur, som en katalysator kræver for at være effektiv. Den væsentligste forskel er det
tørre anlægs brug af kalkpiller, som er højt sammenlignet med det kemikalieforbrug, det
våde anlæg forbruger. Dette gør, at skibe med et tørt anlæg skal have store tanke til
1
International Maritime Organization
2
Bachelor project
2013
kalkpillerne for at kunne sejle længere strækninger. Og samtidig skal der også indhentes
nye forsyninger af kalkpiller, hvilket er mest realistisk, hvis skibet har fast rutefart til de
samme havne.
Der var et tilbud på et vådt afsvovlingsanlæg til rådighed i projektet. I forhold til det blev
der gentagne gange forsøgt at indhente et tilbud til det samme skib på et tørt anlæg fra
Couple-Systems, uden at det lykkedes. Derfor blev der lavet nogle antagelser for at kunne
sammenligne de to systemer økonomisk, hvor det våde afsvovlingsanlæg viste sig at være
en bedre investering, men grundet de usikre antagelser er dette kun vejledende.
Begge afsvovlingsanlæg har vist sig at kunne overholde de krav, som er opstillet til et
afsvovlingsanlæg på skibe. Derfor er hovedkonklusionen, at det ikke har været muligt at
konkludere, om det er det våde eller tørre afsvovlingsanlæg, som er den mest
bæredygtige. Hvert skib må lave deres egen vurdering før valget træffes.
Den positivistiske metode er fundamentet i projektet, og de data som er brugt, er
hovedsageligt fra materiale fundet på nettet samt materiale modtaget fra relevante
personer i afsvovlingsindustrien. Den kvalitative metode er brugt ved de spørgsmål, som
er stillet ved interview og e-mail korrespondance. Empirisk viden fra personer i
afsvovlingsindustrien på kraftværker er brugt til at sammenligne om de data, som er
modtaget fra skibsindustrien er valide.
3
Bachelor project
2013
Table of contents
Nomenclature list ................................................................................................................. 6
Preface ................................................................................................................................ 7
1.
Introduction ................................................................................................................... 8
Initial problem analysis ..................................................................................................... 8
Delimitation .................................................................................................................... 10
Problem statement ......................................................................................................... 11
Theory and Method ........................................................................................................ 12
2.
Why the need for EGCS? ........................................................................................... 13
Environmental impact ..................................................................................................... 13
Exhaust gas ................................................................................................................... 14
Vessel Fuels ................................................................................................................... 14
Composition of the exhaust gas ..................................................................................... 15
SOX and NOX emissions ................................................................................................. 20
Rules and regulations..................................................................................................... 22
The International Maritime Organization (IMO) ........................................................... 22
Marine Environment Protection Committee (MEPC)................................................... 22
MARPOL .................................................................................................................... 23
MARPOL Annex VI Prevention of Air Pollution from Ships ......................................... 24
ECA ............................................................................................................................ 25
Regulation 14 ............................................................................................................. 26
Regulation 4 ............................................................................................................... 28
Regulation 13 ............................................................................................................. 29
Discussion of: ”Why the need for EGCS?” ..................................................................... 31
3.
The EGCS .................................................................................................................. 32
The wet EGCS ............................................................................................................... 32
4
Bachelor project
2013
The wet scrubbing process ......................................................................................... 33
Removal of the sulphur – seawater ............................................................................ 36
Removal of the sulphur – freshwater with chemical reaction ...................................... 37
Different wet Exhaust Gas Cleaning Systems ............................................................ 39
Operating and maintaining the wet EGCS .................................................................. 43
The dry EGCS ................................................................................................................ 45
Discussion of Ca(OH)2 usage ..................................................................................... 49
Operating and maintaining the dry EGCS ................................................................... 50
Summary of: “The EGCS” .............................................................................................. 51
4.
Dealing with nitrogen oxides - NOX ............................................................................. 52
Selective Catalytic Reduction (SCR) .......................................................................... 52
Exhaust gas recirculation system (EGR) .................................................................... 54
5.
Supplying and disposal of the different consumables and residues ........................... 56
6.
Compliance with the regulation ................................................................................... 59
Commenting compliance of wet and dry systems ....................................................... 62
7.
Person gallery ............................................................................................................. 63
Alf Helge Torkelsen, Senior Sales Engineer at Clean Marine A/S .............................. 63
Max Bøgh Frederiksen, Mechanical and Technical Engineer (Maskinmester) at
Esbjergværket (power plant) ....................................................................................... 65
Viggo Rahbek Warming, Operation Engineer at Studstrupværket (power plant) ........ 66
Anders Rooma Nielsen, Catalyst & Process Specialist at Haldor Topsøe A/S ........... 67
Jesper Arvidson, Low Speed Engineering / Operation dept. at MAN Diesel & Turbo . 68
Discussing the Person Gallery .................................................................................... 69
8.
Table comparing wet and dry EGCS .......................................................................... 70
9.
Payback period regarding EGCS ................................................................................ 72
10.
Conclusion ............................................................................................................... 74
5
11.
Bachelor project
2013
Suggestions for further research .............................................................................. 76
Afterword ........................................................................................................................... 76
12.
References............................................................................................................... 78
13.
Appendix .................................................................................................................. 81
13.1 Appendix ................................................................................................................ 81
13.2 Appendix ................................................................................................................ 85
13.3 Appendix ................................................................................................................ 89
13.4 Appendix ................................................................................................................ 94
13.5 Appendix .............................................................................................................. 101
Nomenclature list
Ca(OH)2
Calcium Hydroxide Granulate (lime)
ECA
Emission Control Areas
EGCS
Exhaust Gas Cleaning Systems
EGR
Exhaust Gas Recirculation
FGD
Flue Gas Desulphurization
HFO
Heavy Fuel Oil
IMO
International Maritime Organization
LSMDO
Low-Sulphur Marine Diesel Oil
MDO
Marine Diesel Oil
NaOH
Aqueous Sodium Hydroxide (caustic soda)
PM
Particulate matter
SCR
Selective Catalytic Reduction
6
Bachelor project
2013
Preface
To do my undergraduate internship I contacted Scandic Diesel Services located in
Montreal/Canada. Mikkel Elsborg who is president at Scandic Diesel Services took me into
his company and treated me with respect and kindness. He was very interested in my stay
and he ensured that my time in Montreal became an adventure of a lifetime. Not only
during work hours, but also in my spare time. His idea led to the subject in this project and
he used the contacts in his network to help me realise it. For all of that I am very grateful.
A special thanks to Mikkel Elsborg and Scandic Diesel Services.
I would also like to thank the following persons for helping me with my project:

Alf Helge Torkelsen, Senior Sales Engineer at Clean Marine A/S

Max Bøgh Frederiksen, Mechanical and Technical Engineer (Maskinmester) at
Esbjergværket (power plant)

Viggo Rahbek Warming, Operation Engineer at Studstrupværket (power plant)

Anders Rooma Nielsen, PhD, Chem. Eng, Catalyst & Process Specialist at Haldor
Topsøe A/S

Jesper Arvidson, Low Speed Engineering / Operation dept. at MAN Diesel & Turbo

Anna Eske Jensen, Cand. Scient in physics and chemistry, Lector at Aarhus School
of Marine and Technical Engineering

Kirsten Skaaning, Cand. Mag in English and Information Science, Lector at Aarhus
School of Marine and Technical Engineering
Note that during this project it was not possible to retrieve all the information needed from
the Exhaust Gas Cleaning Systems manufacturers. There has been no response to the
inquiries send to Couple-Systems (the only dry manufacturer).Other attemps to retrieve
information from wet manufacturers failed as well. Therefore I am very thankful for the help
provided to realise this project. Without this help it would have been difficult to get some of
the unknown aspects enlightened due to the lack of technical descriptions on the
manufacturers websites. It is possible that it is due to commercial interests or too many
inquiries from other students as well.
7
Bachelor project
2013
1. Introduction
This bachelor project is about the difference between the wet and dry Exhaust Gas
Cleaning Systems (EGCS). The EGCS can remove sulphur oxide in the exhaust gas on
vessels equivalent to the allowed amount of sulphur content in marine fuel oil.
Currently this is a hot topic due to the change in the allowed sulphur content in marine fuel
oil in 2015 inside Emission Control Areas (ECA).
The bagground for this thesis is the writers graduation project as a Bachelor of Technology
Management and Marine Engineering (Maskinmester) at Aarhus School of Marine and
Technical Engineering.
This subject is choosen in cooperation with Scandic Diesel Services in Montreal/Canada
where the writer did his undergraduate trainee period.
Initial problem analysis
The tighter emission regulations for the marine industry are forcing the vessel owners and
constructors to be innovative and think in new creative ways to solve the increased
demands. Vessels operating within the ECA are already under more strict sulphur
regulations set by the International Maritime Organization (IMO) and European Community
(EC). In the European ports the fuel oil sulphur limits changed from 1.5 %2 to 0.1 % in
2010, and from the first of July 2010 the fuel oil sulphur limits changed from 1.5 % to 1 %
in the ECA (EU - Parliament, 2012, p. 6 and 7). The demands are still increasing both in
and outside the ECA from 2015 to 2025. Vessel owners can meet these new
requirements/regulations by burning fuel with lower sulphur content, for example burning
high-sulphur fuel outside ECA and then switching to low-sulphur (LS) fuel3 when entering
ECA. There are complications when switching between different fuel types because of the
fuel equipment’s technical specifications. The reason is the fuel’s physical characteristics
which are different and it can cause the engine to run improperly - if it can start at all.
2
3
Mass percentage
LSMDO (LS Marine diesel oil)
8
Bachelor project
2013
It is not the only issue when switching to LS fuel because even though sulphur has
lubrication abilities it is also the substance which produces sulfuric acid in the combustion
process. And since cylinder lubrication counteracts that process by its alkalinity the
requirement decreases due to the reduced sulphur amount. An additional issue is the LS
fuel production at the oil refineries due to extension of the process, which the oil goes
through in order to remove the high sulphur content. This results in higher fuel prices
which raise costs for consumers. This process also has an environmental impact, due to
the increased amount of energy used at the refinery. The use of Liquefied natural gas
(LNG) is also known to comply with the regulations, because it has a very low sulphur
content (Kevin J. Reynolds, PE, 2011, p. iii).
There are several ways to comply with the new regulations, but what has recently gained
interest is the Exhaust Gas Cleaning Systems (EGCS) also known as scrubbers. IMO
allow the use of EGCS so the vessels can burn high-sulphur fuel if the EGCS meet the
requirements from IMO about the exhaust emissions (EU - Parliament, 2012, pp. 5 (article
1, 2c)). There are two types of EGCS systems, the wet and dry EGCS technology. Both
technologies are known to reduce sulphur in stationary applications such as land based
power plants burning coal and oil. In the marine industry the EGCS has not yet widely
gained impact although the first prototype of the wet system was installed on a vessel in
1991 (Ryan Albert and Shirley Fan, 2011, p. 2). There are technical and financial
challenges with the EGCS making the vessel owners reluctant about installing the
systems. One of the concerns is that the vessel is off hire4 when installing the EGCS at a
shipyard and if the vessel owners get return of their investment. Do the systems function
and comply with the regulations and what if the regulations change in the future both
locally and worldwide – will the EGCS then be able to comply with future regulations? Can
the EGCS handle any future regulations on Particulate Matter (PM)?5 There are also
issues of wastes from the chemical treatment of the water used in the EGCS.
As these factors give a calculated risk assessment for installing the EGCS it leads to
question if it is the right way to deal with the future requirements and if it would be a longterm sustainable solution?
4
5
The vessel is docked
Not yet regulated
9
Bachelor project
2013
Delimitation
This project will focus on the dry EGCS from Couple-System and the wet EGCS, but only
the open loop, closed loop and hybrid technology. It looks into the present emission
regulations.
Other limitations in this project:

This project will not take future or local changes of sulphur regulations into account.

This project is only including MARPOL Annex VI Regulation 14,13 and 4.

The use of EGCS and switching to LS fuel will not be compared to other solutions of
the sulphur regulation.

This analysis is limited to LSMDO/HFO versus EGCS technology based on two
stroke engine operations.

When looking into the environmental perspective only the impact of air pollution
from vessels is discussed.

The compliance passage of this project deals only with SOX emission.

This project will not cover the environmental impact caused by the discharged water
used in the wet EGCS.

This project is not covering the use of cylinder lubrication in regard of the sulphur
amount in fuel.

Software monitoring of the systems is not explained in this project.

The Selective Catalytic Reduction and Exhaust Gas Recirculation System is the
only NOX reduction devices analysed in this project.

Empirical knowledge from Flue Gas Desulphurization (FGD) systems used on
power plants is obtained to compare land based units with EGCS on vessels.
Technical descriptions of FGD systems are although not included in this project

The fuel oil prices in the future is not analysed in this project
The reason for these limitations was to make sure the focus was on the differences
between the wet and dry EGCS. Without these limitations it would have been difficult to
point out the right direction. Time and resources could have been spent by following a
wrong path.
10
Bachelor project
2013
Problem statement
The considerations in the problem analysis and the details that are explained in the
delimitation, lead to the main issue:
Which one of the exhaust gas cleaning systems is the most sustainable in order to
comply with the future regulations/requirements – the wet or dry technology?
To answer the question the following points will be analysed:
 What are the known rules and regulations today?
 How does the wet and dry Exhaust Gas Cleaning System function?
o Wet system
o Dry system
o Operation and maintaining the system
o The difference between the wet and dry system
 Advantages / disadvantages
o Combination of EGCS with NOX emission reduction equipment
o How can EGCS be compliant with the regulations?
o Payback period of EGCS
11
Bachelor project
2013
Theory and Method
The background of the writer to this project is a lot of technical basic knowledge obtained
through his earlier profession as a car mechanic and through his nearly finished education
as Bachelor of Technology Management and Marine Engineering (Maskinmester). This
knowledge gives the writer abilities to consider the reliability and validity of the consumed
information and he knows how to ask relevant questions to the people who were
interviewed in the process.
This project is based on positivism. It means that the mind-set behind this project is based
on logical and rational observations to reach the conclusion. The information in this project
is from different kind of sources like published handbooks online and from reliable people
working in the emission reduction industry. To make this project up to date, the sources of
information are as new as possible.
The provided information was double checked as much as possible to confirm the
reliability of it and the providers interest in the outcome of this project were considered in
order to reach the conclusion without any misleading information. To get as exact answers
as possible the questions asked at the interviews and through email correspondence was
made in the qualitative way. Asking the exact questions in order to analyse and investigate
what was the essential about the problem.
Although Flue Gas Desulphurization (FGD) systems used on power plants is not described
in this project, empirical knowledge from the industry is used to confirm some of the
discovered aspects in this project.
12
Bachelor project
2013
2. Why the need for EGCS?
Environmental impact
Vessels are like any other device running on fossil fuel and thereby affect the environment
due to the discharged exhaust gases. Note that here only ship emission is focused on and
not the other environmental impact like discharge of stored wastes from the vessels.
It is a commonly known fact that the world population is increasing and thereby the need
for transportation and shipping is also increasing because of the rising demand for goods
and globalisation.
Figure 1: Global energy consumption in 2000 (Kuiken, 2008, p. 145)
Figure 1 shows the global energy consumption in year 2000 that illustrates how much
shipping is contributing to global emissions. The figure is from year 2000 which currently
makes it 13 years old and it must be assumed that the global energy consumption has
changed a little since then. It still gives an idea of how much the worldwide shipping
consumes.
13
Bachelor project
2013
Exhaust gas
The exhaust gas composition is dependent on a lot of factors like the fuel composition and
the quality of the combustion in the diesel engine which is highly influenced by the injection
timing, the quality of the injection and the overall performance of the engine,
turbochargers, cylinders, pistons etc.
The discharged exhaust gas by the marine industry is divided into different groups. Some
of which are contributing to the believed climate change by the greenhouse effect, others
are classified as pollutants, solid particles (PM) and vapours derived from the fuel and the
lubricants used in diesel engines.
Vessel Fuels
Since there are no global standardisation of marine fuels these abbreviations are used in
this project:
Fuel type
Abbreviated
Sulphur content in %
Heavy Fuel Oil
HFO
>1.5 %
Low Sulphur Heavy Fuel Oil
LSHFO
≤1.5 %
Marine Diesel Oil
MDO
<1%
Low Sulphur Marine Diesel Oil
LSMDO
≤ 0.1 %
Vessel fuels are known under different names with each their abilities and prices. Some
are called Heavy Fuel Oil (HFO) which is the oil referred to as high-sulphur fuel. It is the
remaining residue after the distillation process at the refinery. To obtain the correct
viscosity the residual fuel is mixed with lighter fuel distillates. HFO is characterised by its
high specific mass and high viscosity. Due to the high viscosity the HFO needs to be
heated to a maximum of 150oC in order to pump the fuel and since it is the residue after
the distillation HFO has to be cleaned by using centrifuges (Kuiken, 2008, p. 137). The
HFO can be of different quality and can be bought with a high sulphur level above 1.5 %. It
is also available with a lower sulphur content known as Low Sulphur Heavy Fuel Oil
(LSHFO) which is with a sulphur level under or equal to 1.5 %.
Marine Diesel Oil (MDO) is the oil referred to as low sulphur fuel. This fuel is the distillates
after the refining process added a small amount of residues. MDO is characterised by its
low sulphur content and low viscosity which means that it does not need any heating for
14
Bachelor project
2013
pumping although it can have problems with blockage of the piping system because of
crystallisation called flocculation (Kuiken, 2008, p. 137). MDO can also be obtained with
ultra-low sulphur content with a maximum of 0.1 %.
Generally vessels run on HFO. Auxiliary engines use distillates like LSMDO which are
more expensive than HFO and that is why the marine industry is operating about 95 % on
HFO and the last 5 % is on other distillates like LSMDO (Ministry of transport, 2009, p. 10).
The fuel composition is very important regarding emissions in the exhaust gas e.g.
operating on low-sulphur fuel can easily decrease the sulphur level in the exhaust gas, but
fuel is more than sulphur. Fuel consists of carbon, hydrogen, oxygen, nitrogen, sulphur,
water and a lot of various metals etc. Today the quality of fuels can be different from each
bunkering because to obtain lower sulphur content in HFO, the residues is mixed with
distillates to lower the sulphur content – making it difficult to predict the quality of the fuel
and samples must be examined upon bunkering.
Composition of the exhaust gas
In regard to the exhaust gas composition one significant substance is the amount of air in
the diesel engine which has to be higher than the theoretical required amount of air. This is
because the oxygen needed to make a complete combustion must be placed exactly
where the injected fuel is sprayed to get the complete combustion and that is not working
in practical. Therefore the amount of air needed to create a complete combustion must be
higher which is given by the lambda value.
In figure 2 an example of a Wärtsilä two-stroke crosshead engine is showing the exhaust
gas composition operating on HFO with a sulphur content of approximately 3.5 %:
15
Bachelor project
2013
Figure 2: Wärtsilä two-stroke crosshead engine (Kuiken, 2008, p. 145)
To give an example of the lambda value this engine has an air consumption of 7.8 kg/kWh.
The air consists of 21 % oxygen (O2) and therefore the incoming air to the engine contains
kgO2/kWh and the exhaust gas contains 1.1 kgO2/kWh.
Therefore is the oxygen used in the combustion process
kgO2/kWh.
That gives the lambda value (Kuiken, 2008, p. 145):
This means that on two-stroke diesel engines three times or more air is used than
theoretical needed, some of it is used in the scavenging process but most of it in the
combustion. It is important when looking at the exhaust composition because the air
consists of roughly 21 % O2 and 79 % nitrogen (N2) hence adds the extra O2 to the level of
the produced SOX and NOX.
16
Bachelor project
2013
The exhaust composition is:
Figure 3: Exhaust gasses (Kuiken, 2008, p. 147)
Nitrogen - N2: Due to the amount on nitrogen in air, exhaust gases consists of a large
amount of nitrogen as well. It is not important because nitrogen is an inert 6 gas under
these conditions.
Oxygen - O2: Oxygen is required in the combustion process and it is always in the
exhaust gases due to the excess air. The Exhaust gases contain about 13 to 16 % O2 and
the data from the Wärtsilä engine confirms that:
Water vapour – H2O: Water vapour is formed due to the hydrogen which reacts with the
oxygen.
Carbon Dioxide – CO2: The injected fuel contains carbon and it reacts with the oxygen so
carbon dioxide is produced. Carbon dioxide is known to contribute to the discussed
greenhouse effect. The ways to decrease carbon dioxide is to use light fuel with a lower
carbon quantity or/and optimize the engine and thereby lower the fuel consumption.
6
It is a gas that does not undergo a chemical reaction under these conditions
17
Bachelor project
2013
Sulphur oxide – SOx: Sulphur oxide is formed in a perfect combustion and it is a reaction
between sulphur and oxygen. Sulphur dioxide SO2 and sulphur trioxide SO3 is formed in
that reaction. The main compounds in acid rain are sulphur oxides, it is also very
unhealthy to the human respiratory system and it can dissolve building material like soft
limestone (Kuiken, 2008, p. 147). Seawater which is slightly alkaline can easily neutralise
sulphur in the exhaust gas.
Hydrocarbon – HC: Hydrocarbons is a reaction between hydrogen and carbon. Hydrogen
can react in any possible chemical combination of carbon, oxygen, nitrogen and sulphur in another word hydrocarbon compounds. These combinations are in very low
concentrations. The impacts from these reactions are difficult to predict due to the low
concentration, but it is generally a result of the parameters in the combustions process and
is due to an imperfect combustion. The amount of hydrocarbon compounds is in well-tuned
engines kept to a minimum.
Carbon monoxide – CO: Carbon monoxide is a product due to an imperfect combustion
where the amount of oxygen is too low and thereby not turned into CO 2. It is merely
happening close to the cylinder walls of the combustion chamber or if the air and fuel
mixture is insufficient. It is a transparent and odourless gas which is very toxic for both
fauna and man. It can kill instantly if inhaled in higher concentrations known from e.g.
suicidal incidents using a car and the accidents from using a barbecue in a garage.
Therefore it is very important to make a complete combustion through the use of high
amount of oxygen and create a good air and fuel mixture in the combustion chamber.
18
Bachelor project
2013
Nitrogen oxides – NOX: Nitrogen oxides is a product of different compounds but mostly
known as NO or NO2. It is produced when there is a high temperature and an excess of
oxygen during the combustion which is inevitable in diesel engines. Upon leaving the
combustion chamber some of the NO oxidises to nitrogen dioxide (NO 2), approximately 90
– 95 % NO and 5 – 10 % NO2. Together it is called NOX (EGCSA, 2012, p. 67).
Measures to lower the temperatures are used in diesel engines such as recirculating some
of the exhaust gas back to the inlet air and thereby give the same filling of the cylinder, but
with less oxygen. This also decreases the combustion temperature. The amount of NOX is
thereby due to the amount of nitrogen in the fuel, the combustion temperature, the time of
that temperature during the combustion process and the amount of oxygen. Heavy fuel
contains more nitrogen than light fuel, but in general fuel contains only smaller amounts of
nitrogen (Kuiken, 2008, p. 148).
Solids: There are different solids in the exhaust gas.
Some of them are (Kuiken, 2008, p. 150):
”carbon, ash particles, heavy metals, precipitated sulphur
oxides, water, corrosion particles and a variety of partially combusted
hydrocarbons from the fuel and the lubricating oil”
They are less than 1µm and therefore the solids are easily carried out by the exhaust air.
19
Bachelor project
2013
SOX and NOX emissions
Diesel engines are the predominant means for propulsion of vessels. Usually there are
several diesel engines on board like the main engine and auxiliary engines to power the
vessel with electricity. The use of HFO is widely used in the marine industry which means
that the amount of sulphur is above 2.3 %. 95 % of vessels with a two-stroke low speed
engine installed are sailing on HFO and the remaining 5 % is using MDO. 70 % of vessels
with medium speed engines use HFO and the last 30 % are propelled using MDO or
LSMDO. The overall picture is that approximately 80 % of international shipping consumes
HFO (OECD, 2011, p. 54).
The premature deaths caused by the shipping industry due to the use of HFO is difficult to
conclude but an estimation made in 2008 claimed that pollution from international shipping
would cause 80.000 or more premature deaths every year by 2012. The estimation was
based on the use of HFO with an average sulphur content of 2.7 %.
It is also assumed that (OECD, 2011, p. 54):
“A “global scenario”, with all ships using marine distillate fuel with a 0.5%
sulphur cap, could cut premature mortality rates by around 60%, to 33 700”.
Estimations made to conclude the amount of sulphur dioxide (SO 2) discharge caused by
humans globally showed that 10 % originated from international shipping. That is
compared to the 50 % which is caused by industrial coal consumers on land (EGCSA,
2012, p. 7). Thus is the sulphur discharge by the marine industry relatively low but is still
contaminating the environment.
In the atmosphere the general amount of SO2 is less than 10 parts per billion (ppb7). SO2
has a suffocating odour if the amount reaches a level around 500 ppb where it can be
fatal. Amounts lower than 500 ppb and above 20 ppb can cause eye irritation and
respiratory problems may be experienced depending on the time exposed. It is worse if the
person exposed is dealing with bad health like people with asthma or chronic lung or heart
diseases (EGCSA, 2012, p. 7).
The most commonly known problem with the SO2 emission is that the discharge of sulphur
into the atmosphere is a (OECD, 2011, p. 54):
” major cause of acid rain and the acidification of soil, groundwater and lakes”
7
-9
10
20
Bachelor project
2013
Figure 4: Wet and dry acid deposition (Likens, 2011)
The problem with SO2 emission is that it oxidises into sulphur trioxide (SO3) and then
reacts with water in the atmosphere and turns into sulphuric acid (H 2SO4) which
unfortunately is the main reason for acid rain:
SO2 + 1/2O2 + H2O = H2SO4
Even though NOX is a minor component to acid rain compared to SOX it is still a significant
pollutant. It contributes to the formation of ground level ozone which is a major health
hazard. It can cause irritation of the respiratory system and can harm lung function. Ozone
is also causing reduced crop yields, vegetation damage and it is also a greenhouse gas
(OECD, 2011, p. 56).
21
Bachelor project
2013
Rules and regulations
The International Maritime Organization (IMO)
IMO is the main international maritime organization established by the United Nations (UN)
in 1948 and entered into force in 1958 (IMO, 2013). IMO’s main purpose was to ensure
cooperation between the countries in order to heighten the safety in the marine industry.
Currently IMO has 170 member states and three associate members. In the beginning
MARPOL’s main purpose were to ensure the safety of life at sea which led to (SOLAS)8 in
1960. After that IMO turned its attention on the polluting side of the marine industry.
Today IMO's mission statement is as stated in Resolution A.1011(26) from 2010 to 2015
(IMO, 2013):
"The mission of the International Maritime Organization (IMO) as a United
Nations specialized agency is to promote safe, secure, environmentally
sound, efficient and sustainable shipping through cooperation. This will be
accomplished by adopting the highest practicable standards of maritime safety
and security, efficiency of navigation and prevention and control of pollution
from vessels, as well as through consideration of the related legal matters and
effective implementation of IMO’s instruments with a view to their universal
and uniform application"
So as stated by their mission today they are still ensuring safety but they are also focusing
on the pollution side and that’s why IMO is important in this matter.
Marine Environment Protection Committee (MEPC)
IMO has five main committees that consist of all member states. The marine environment
protection committee (MEPC) is one of them and it is empowered to consider any matter
within IMO in regard to prevention and the control with pollution from vessels.
The MEPC is in particular concerned with (ECG, 2011, p. 3):
”the adoption and amendment of conventions and other regulations and
measures to ensure their enforcement (e.g. MARPOL)”
The MEPC was first a helping committee of the IMO but in 1985 it was raised to full
conventional status (IMO, 2013).
8
Safety of life at sea
22
Bachelor project
2013
MARPOL
The environmental impact created by the emission from vessels has thus led to rules and
regulations demanded internationally by the International Convention for the Prevention of
Pollution from Ships also known as (MARPOL – abbreviated from marine pollution). The
main international convention for preventing pollution from the marine industry is
MARPOL. Important years are the IMO adoption of the MARPOL Convention in 1973 and
the protocol of 1978 which went into effect 2 October 1983 and that is why it is called
MARPOL 73/78. In 1997 another amend was made to the convention to address the
pollution problem which is why Annex VI was added and it went into force on 19th May
2005 (IMO, 2013).
There are different annexes to address when joining MARPOL. To become member the
countries must ratify at least annex I and II out of six – as of November 2011 151 states
have ratified the first two annexes (ECG, 2011, p. 3).
The MARPOL ANNEXES (IMO, 2013):”

Annex I Regulations for the Prevention of Pollution by Oil (entered into force 2
October 1983)

Annex II Regulations for the Control of Pollution by Noxious Liquid Substances in
Bulk (entered into force 2 October 1983)

Annex III Prevention of Pollution by Harmful Substances Carried by Sea in
Packaged Form (entered into force 1 July 1992)

Annex IV Prevention of Pollution by Sewage from Ships (entered into force 27
September 2003)

Annex V Prevention of Pollution by Garbage from Ships (entered into force 31
December 1988)
 Annex VI Prevention of Air Pollution from Ships (entered into force 19 May 2005)”
This project is only focusing on Annex VI
23
Bachelor project
2013
MARPOL Annex VI Prevention of Air Pollution from Ships
The MARPOL Annex VI regulates emissions from the marine industry which are engaged
in international trade and regulations. According to IMO 73 states have on 30th April 2013
ratified Annex VI (IMO, 2013). The convention went into force 19 May 2005 where
regulation 14 set the limit of sulphur content in fuel oil inside SOX Emission Control Areas
(SECA) to be 1.5 % by using fuel with lower sulphur content. An approved EGCS could be
used as an alternative way to lower SOX emissions. On 11th August 2006 the Baltic Sea
fully implemented SECA as the first area. Exactly one year later on 11th August 2007 the
English Channel and the North Sea joined SECA under European Commission Directive
2005/33 (EU - Parliament, 2005, p. 64). After the implementation of MARPOL Annex VI in
2005 IMO began to review the emission limits with the sight of strengthening the emission
limits according to technological progress and empirical experiences of emission
prevention technologies. This led to a revised Annex VI in 2008 where the NOX Technical
Code was adopted and entered into force in July 2010 (EGCSA, 2012, p. 15). At the same
time the SOX word was erased from the SECA name in some areas due to the added NOX
regulation and today these areas are called Emission Control Areas (ECA).
Figure 5: Current and future ECA (Lloyd's Register, 2012, p. 8)
24
Bachelor project
2013
ECA
ECA are defined as an (EGCSA, 2012, p. 15):
”area where the adoption of special mandatory measures for emissions from
ships is required to prevent, reduce and control air pollution from NOx or SOx
and particulate matter or all three types of emissions and their attendant
adverse impact on human health and the environment”
This means that the ECA are widened so restrictions can contain other than SOX
emissions. The Baltic and North Sea will remain a SECA but the sixtieth session of MEPC:
”adopted a proposal from the USA and Canada for an ECA extending 200
nautical miles from both east and west coasts and around the islands of
Hawaii” (EGCSA, 2012, p. 15).
On 1th August 2012 it became fully implemented in North America setting the sulphur
content in fuel oil to 1 %. Similar to this the ECA will be implemented around Puerto Rico
and the U.S Virgin Islands on 1th January 2014.
As of June 2012 there are discussed new ECA implementing around the world according
to a presentation from Couple-Systems e.g. in the Australian waters and the
Mediterranean Sea. Note that the presentation is from June 2012 and therefore figure 6 is
edited to be up to date.
Figure 6: Discussed ECA as of June 2012 (Jürgens, 2012) - edited
25
Bachelor project
2013
California
California is special because they have their own regulation on sulphur emission for ocean
going vessels stretching an area of 24 nautical miles from the California baseline and
within the waters. They only give permission to the use of EGCS as a trial program
allowed by the California authorities, and after the trials the vessels must be fitted back
into compliance with the California fuel requirements (Lloyd's Register, 2012, p. 49).
Figure 7: Fuel regulation requirements in California (Lloyd's Register, 2012, p. 49
The most important regulations of MARPOL Annex VI in regards of this project are
regulation 14, 4 and 13.
Regulation 14
Regulation 14 place limits on sulphur content in marine fuel oil in order to lower SOX and
PM emissions. It is applicable to all vessels that are in service and it depends where the
vessels are sailing, if it is inside or outside ECA. There is no limit on PM yet, but it is
regulated indirect by the limits on sulphur content in marine fuel oil due to the sulphurs
contribution on PM emissions. A special regulation are on passenger vessels (RoPax)
sailing outside ECA between the European members states setting the sulphur limit to 1.5
% and member states are obligated to ensure the regulation are followed like the
2012/33/EU sulphur directive claims (EU - Parliament, 2012, p. 6):
” Member States shall take all necessary measures to ensure that marine
fuels are not used in their territorial seas, exclusive economic zones and
pollution control zones falling outside SOx Emission Control Areas by
passenger ships operating on regular services to or from any Union port if the
sulphur content of those fuels exceeds 1,50 % by mass until 1 January 2020”.
After 1th January 2020 the limit will be set to 0.1 % on the passenger vessels.
26
Bachelor project
2013
Important dates and regulations on sulphur content in marine fuel oil outside ECA (IMO,
2013):

4.50 % m/m prior to 1 January 2012

3.50 % m/m on and after 1 January 2012

0.50 % m/m on and after 1 January 2020 - (2025)
The 0.50 % on 1 January 2020 is depending on an IMO review in 2018 regarding the
availability of low sulphur fuel oil due to if it is possible to implement the global regulation in
2020 or 2025 as illustrated in figure 8 (EGCSA, 2012, p. 15).
Important dates and regulations on sulphur content in marine fuel oil outside ECA (IMO,
2013):

1.50 % m/m prior to 1 July 2010

1.00 % m/m on and after 1 July 2010

0.10 % m/m on and after 1 January 2015
Figure 8: MARPOL Annex VI – sulphur limits implementation (ECG, 2011, p. 12)
27
Bachelor project
2013
To ensure that these regulations are followed there are different responsibilities which are
demanded by regulation 18. Regulation 18 supports regulation 14 by setting out the
responsibilities which the marine fuel oil supplier and the vessel owner must follow. This is
explained very briefly since this regulation is seen as a support to regulation 14 in regard
of the aspect which is outside of the vessel owner’s control.
The Marine fuel oil supplier must ensure that the sulphur content referred to in figure 8 is
not exceeded according to regulation 18, but still the vessel owner is implied to do all
necessary measures to ensure that the sulphur content is compliant with the regulations
(DNV, 2009, p. 25).
The vessel owner is also obligated to document that the fuel oil complies with regulation
14 when the vessel is entering or leaving an ECA if the vessels is operating on different
marine fuel oils. The vessel shall carry a written procedure which is documenting how the
change over from the different fuels is to be done as prescribed by the administration. It
must ensure that the change-over is done sufficiently regarding the time before entering an
ECA to ensure all high sulphur fuel oil is flushed out of the system.
The needed documentation recorded in the logbook for change-over is:

The time and date

The vessels position

The volume of low sulphur fuel oils in each tank
When leaving an ECA the documentation must show that the change over from low
sulphur fuel oil is done outside the ECA.
Regulation 4
Regulation 4 allows the use of alternative methods to lower SOX emission if they are at
least as effective in terms of emission reduction as the prescribed sulphur limits in
regulation 14. This means that a vessel can operate on high sulphur fuel oil if an approved
EGCS is fitted according to reduce the SOX emission equivalent or lower than the
compliant fuel emissions. If an EGCS is fitted it must be compliant according to IMO
(Lloyd's Register, 2012, p. 7). For further information see the: ”Compliance with the
regulation” passage.
28
Bachelor project
2013
Regulation 13
Regulation 13 set limits on nitrogen oxides (NOX) emissions from marine diesel engines. It
applies to (IMO, 2013):

Diesel engines installed on or after 1th January 2000 with a power output of or more
than 130 kW

Diesel engines that undergo a major conversion on or after 1th January 2000 – like
changing the engine or system components regarding NOX emission e.g. fuel
injectors

Diesel engines installed on or after 1th January 1990 but prior to 1th January 2000
with a power output of or more than 5000 kW, or with a cylinder displacement at or
above 90 litres per cylinder
In accordance to the above there are three limits and dates to notice which are called
TIER I, II and III.
Figure 9: MARPOL Annex VI - NOX schedule (Lloyd's Register, 2012, p. 8)
The TIER limits depend on how many revolutions per minute (rpm) the diesel engine
operates. This is due to the time during combustion since the time where there is a high
temperature in the combustion chamber is significantly increasing NOX. If the rpm (n) is
from 130 to 1999 the formula is used to find the maximum limit e.g. TIER II (44 n-0.23).
29
Bachelor project
2013
TIER I – outside ECA
TIER I applies to diesel engines installed on or after 1th January 2000 to 1th January 2011
and marine diesel engines installed on or after 1th January 1990 but prior to 1th January
2000 with a power output of or more than 5000 kW, or with a cylinder displacement at or
above 90 litres per cylinder. It also includes diesel engines on vessels from before 1th
January 2000 that undergo a major conversion.
The limit is (45 n-0.2) depending on the rpm from under 130 and equal to or above 2000:

Lowest limit = 45 2000-0.2 9.8 g/kWh

Highest limit = 45 130-0.2 17 g/kWh
Marine diesel engines failing to comply with these limits are prohibited.
TIER II – outside ECA
TIER II applies to diesel engines installed on vessels on or after 1 January 2011.
The limit is (44 n-0.23) depending on the rpm from under 130 and equal to or above 2000:

Lowest limit = 44 2000-0.23 7.7 g/kWh

Highest limit = 44 130-0.23 14.4 g/kWh
Marine diesel engines failing to comply with these limits are prohibited.
TIER III – inside ECA
TIER III is subject to a technical review from IMO which is supposed to be concluded in
2013 hence the implement of TIER III could be delayed according to MARPOL Annex VI
regulation 13.10 (IMO, 2013). TIER III will only apply in ECA i.e. North American and US
Caribbean ECA, and there is to date no suggestions to add ECA to the North and the
Baltic seas which will remain SECA (IMO, 2013).
TIER III is supposed to be implemented on 1th January 2016 which applies to all marine
diesel engines to the limit that is (9 n-0.2) depending on the rpm from under 130 and equal
to or above 2000:

Lowest limit = 9 2000-0.2 2 g/kWh

Highest limit = 9 130-0.2 3.4 g/kWh
Marine diesel engines failing to comply with these limits will be prohibited unless the limits
are changed according to the above mentioned review.
30
Bachelor project
2013
Discussion of: ”Why the need for EGCS?”
There is no doubt that emissions from vessels have an influence on the environment. The
concern about SOX is the predominant in this project. The overall picture is that 80 % of
international shipping consumes HFO. The data used from the research on the impact by
using HFO, e.g. the premature deaths caused by SOX may be misleading since the impact
caused by the marine industry is difficult to measure. Some assumption was made in order
to reach the conclusion which is why the data is not considered valid. Although it gives a
picture of how SOX emissions influences the environment. The main concern about SO X is
that it leads to acid rain.
The rules and regulations set by MARPOL Annex VI Regulation 14 sets the limit for
sulphur content in fuel oil for member states and in ECA. MARPOL Annex VI Regulation
13 sets the limit for NOX emission by TIER I, II and III.
What is important to notice and remember for further reading are:

The next important date is 1th January 2015 where the sulphur content in fuel oil is
regulated to 0.1 % in ECA

TIER III is maybe implemented on 1th January 2016 which tightens the NO X limit in
ECA

Currently the North and Baltic Sea is only SOX ECA and thereby not under TIER III

MARPOL Annex VI regulation 4 allows an approved EGCS instead of LSMDO
31
Bachelor project
2013
3. The EGCS
The wet EGCS
The wet EGCS systems have four basic components (EGCSA, 2012, p. 35):
1. The exhaust gas cleaning unit (EGC unit), placed high up in the vessel due to
available space and to get easy access to the unit. Mostly it is placed in or around
the funnel area.
2. A water treatment plant in order to clean the used scrubbing water before discharge
overboard.
3. A facility to handle sludge from the water treatment plant.
4. Controls and instruments in order to measure the exhaust gas and maintain the
EGCS. (not shown on figure 10)
1
2
3
Figure 10: Basic wet EGCS (EGCSA, 2012)
32
Bachelor project
2013
The wet scrubbing process
The wet scrubbing principle is a method undergoing three steps:
1. Create water droplets in a size range of around 100µm to 1000µm.
2. Force the water droplets to make contact with the exhaust gas.
3. Dry the cooled cleaned exhaust gas by removing the contaminated water droplets.
To create water droplets in the wet system the use of a pressure drop through appropriate
shaped nozzles is the most common way (EGCSA, 2012, p. 60), but there are different
ways to design the tower in order to mix the water with the contaminant which is illustrated
in figure 11.
Figure 11: Classical types of wet towers (EGCSA, 2012)
The general idea is to mix the exhaust gas with the water in order to remove the sulphur.
At the same time some of the PM is removed. The different designs use their own special
technique. The spray tower sprays directly into the exhaust gas through multiple nozzles.
The cyclonic use the centrifugal principle in order to mix and coalescence the water with
33
Bachelor project
2013
the sulphur and PM where the velocity of the round going exhaust stream forces the water
out to the wall due to the higher density of the water. The packed bed removes
contaminants by leading the exhaust gas through a packed structure that provides a larger
surface for the water droplets thus is the mixing created by the flow in the narrow space in
the wet packed bed surface. In the water bath the exhaust stream is pressed through the
water where the exhaust gas dissolves and mixes with the droplets. The bubble plate
system uses only one injection nozzle by spraying the water over the bubble plates using
the larger surface area and narrow spaces to mix the gas and water. The venturi system
have only one injection nozzle, but because of the high velocity of the exhaust gas in the
venturi channel it is possible to reach a suitable mix of the water and exhaust gas.
The different designs are not explained further in this project due to the focus between the
wet and dry EGCS. The designs must nevertheless be made so it fits the requirements
from the vessel owner according to available space on the vessel, if it’s a refit or retrofit
and to optimize benefit to cost ratio.
When particles impact with the water droplets it is believed that three processes of particle
removal occur (EGCSA, 2012, p. 58):
1. The particle impacts directly with the water droplet.
2. Through interception where the droplet is not fully displaced around the particle.
3. By molecules bumping randomly into each other (Brownian motion) and by
diffusion is trapped by the water droplet.
Figure 12 shows the three ways of trapping the contaminants. Exhaust gas has a very low
density, it will therefore stream past the water droplets. Also, the larger particles, with
(their) higher density, stream forward with more inertia and are thus resistant to change
their path. This allows for impacts with the water droplets. Therefore the best effect in
order to trap the larger particles is by the having a high velocity between the water droplets
and the particles – it means more inertia effect. Medium sizes particles tend to follow the
exhaust gas stream around the edge of the water droplet but are still trapped. Fine
particles less than 1µm with lower density follow the exhaust gases direction but due to the
Brownian motion of molecules bumping randomly into each other, the particles are trapped
by diffusion and the force of attraction between small and larger particles (Jensen, 2013).
It is different with ultrafine particles (100nm range) which have a very low mass and
34
Bachelor project
2013
therefore act the same way as the exhaust gas. To deal with those particles a coalescing
technique is required and it is done by using water vapour which makes the particles come
together. It forms bigger particles that are now wet and heavier causing them to stream out
with the scrubbing water.
Figure 12: Trapping particles (EGCSA, 2012, p. 58)
The wet scrubbing process is to make a large scale of water droplets and water vapour in
order to separate the contaminant from the exhaust gas. But to assure a proper scrubbing
of the exhaust gas, the velocity of the exhaust gas must be varied as well because the
large particles are trapped using a direct impact method with a high velocity. However the
finer particles and those particles requiring coalescing technique tend to be easier trapped
using a lower velocity with less turbulence (EGCSA, 2012, p. 60). Therefore the wet EGCS
are designed with all that in mind, water droplets and vapour, different velocity of the
exhaust stream and the mixture of exhaust gas and water in order to separate the
contaminated water.
There is also another thing to consider in the wet system. It is due to the decreased
velocity of the exhaust gas leaving the funnel if the design is insufficient in getting the
exhaust gas into the atmosphere and away from zones where human activity is located.
35
Bachelor project
2013
There is also a concern with the relative humidity of the cleaned exhaust gas which is
close to 100 % upon leaving the EGCS. That may be a concern under cold atmospheric
conditions where the surrounding air cools down the saturated cleaned exhaust gas
making a condensation plume of moist air just outside the funnel. It leaves a white stream
of water condensate in the surroundings next to the funnel area including some of the
pollutants.
There are some ways to address the problem with getting the exhaust gas into the
atmosphere (EGCSA, 2012, p. 63):

Increase the velocity of the outgoing exhaust gas by using a constricted gas exit,
but that may cause a problem with back pressure issues.

The cooled cleaned exhaust gas can be re-heated to increase buoyancy which also
removes the risk of condensation of the water in the gas due to a lower relative
humidity. This would require additional energy if a solution with using waste heat
recovery is impractical.

The velocity of the outgoing exhaust gas is increased using an induced draft fan.
This option also requires additional energy but is a viable way of solving
backpressure issues.
There are therefore different solutions to solve the problem and (EGCSA, 2012, p. 63):
“Most designers make arrangements to avoid the plume formation”
The wet EGCS is able to remove sulphur and about 60 to 90 % PM from the exhaust gas
(Lloyd's Register, 2012, p. 29). There are issues which the designers are aware of with the
moist and velocity of the exhaust gas leaving the funnel and it should be addressed upon
the final choice when purchasing the system.
Removal of the sulphur – seawater
Wet EGCS that use seawater as a scrubbing medium have the advantage that there is
always enough water available. It requires the water to be mixed sufficiently with the
exhaust gas before the reactions take place. In the exhaust gas the amount of sulphur
dioxide (SO2) highly exceeds the very small percentage of sulphur trioxide (SO3). SO3 is
more common when the exhaust gas reaches the atmosphere where the amount of
oxygen is higher and it allows the SO2 to oxidise into SO3. Nevertheless the SO3 is also
removed from the exhaust gas as shown in figure 13.
36
Bachelor project
2013
Figure 13: Chemical reaction scrubbing with seawater (EGCSA, 2012, p. 12)
When SO2 is dissolved in seawater, the reaction that occurs is in fact the sulphur dioxide
(SO2) and the water (H2O)
bisulphite
(HSO3-)
reacting to sulphurous acid, that then rapidly
and then/finally ionise to sulphite
(SO32-)
ionise to
which in turn rapidly oxidize to
sulphate due to the oxygen in the seawater.
These reactions leave excess hydrogen (H+) ions (acidity) as well as the small amount of
SO3 reacts to sulphuric acid (H2SO4). This acidity is initially neutralized by the seawaters
buffering capacity. However when the pH level reaches approximately 3 the removal of the
sulphur becomes limited because the reaction of SO2 to sulphite is negligible (EGCSA,
2012, p. 40).
Hence the amount of seawater used to scrub the exhaust gas has to be appropriate in
order to remove the sulphur content. If the amount is too low the required sulphur
reduction is not achieved. If the amount is higher than needed, the use of energy to pump
the seawater and the component size / weight is inefficient. The temperature of the
seawater is also influent, because lower temperature increases the SO2 solubility
(EGCSA, 2012, p. 40).
Removal of the sulphur – freshwater with chemical reaction
The sulphur can also be removed by using freshwater with the addition of a suitable
alkaline chemical where the majority of EGCS use sodium hydroxide (NaOH) also known
as caustic soda. The advantage of this system is that it can be used in a closed system
with only a small amount of water residue which can be stored when sailing in areas
sensitive to overboard washwater.
The reactions between SO2 and water are the same in this system as with seawater where
the final product is sulphate and excess acid.
37
Bachelor project
2013
NaOH added to water expressed as aqueous sodium hydroxide:
Figure 14: Scrubbing media - aqueous sodium hydroxide (EGCSA, 2012, p. 40)
NaOH for the wet EGCS is usually a 50 % solution – a mixture of water and NaOH9
When scrubbing with NaOH (EGCSA, 2012, p. 41):
”The overall reactions with SO2 therefore produce a mixture of sodium
bisulphite, sodium sulphite, and sodium sulphate. The exact proportions of the
sulphur species depend on the pH and degree of oxidation”
Figure 15: Sodium hydroxide to sodium sulphate (EGCSA, 2012, p. 41)
The added NaOH and the increased alkalinity enable the washwater circulation rate to be
approximately 20 m3/MWh10. It is less than half of the seawater system which is
approximately 45 m3/MWh. It gives this system the advantage of using less energy to run
the water pumps, less discharge rates and have less corrosion issues of system
components due to higher alkalinity. Furthermore this system also needs storage to handle
NaOH, additional coolers to the circulating washwater, water treatment plant to handle
circulated water and freshwater capacities in case of additional freshwater needs in the
system (EGCSA, 2012, p. 41). Typical chemical systems use a 50 % NaOH solution and
the dosage rate is 15 litres/MWh when 2.7 % sulphur HFO is scrubbed to the equivalent of
0.1 % sulphur content.
9
From now on the aqueous sodium hydroxide is referred to as “NaOH”
When operating on an average sulphur content at approximately 2.7%
10
38
Bachelor project
2013
Different wet Exhaust Gas Cleaning Systems
The Open Loop EGCS
Figure 16: Open Loop Exhaust Gas Cleaning System (EGCSA, 2012, p. 37)
The open loop EGCS is a process where seawater is used as scrubbing water. Therefore
additional pumping is required at the sea chest to feed the EGCS. After the scrubbing
process the contaminated water is going through the wash water treatment whereby some
of the contaminant is separated. The cleaned washwater is then pumped overboard like
the engine cooling water. Typical required water usage in an open water system is 45
m3/MWh when operating on fuel with a sulphur limit of 2.7 % (EGCSA, 2012, p. 37). The
open loop system can be insufficient if alkalinity level in the seawater is too low.
39
Bachelor project
2013
Closed Loop EGCS
Figure 17: Closed Loop Exhaust Gas Cleaning System (EGCSA, 2012, p. 38)
The closed loop scrubbing process is as the name says a closed loop where most of the
water is recirculated after the scrubbing process. Before recirculation the contaminated
water is cleaned and cooled in the process tank which also functions as a buffer tank. The
most typical media is freshwater, seawater is also possible, (EGCSA, 2012, p. 38).
Chemicals and additional water are added to keep alkalinity level up. The amount of water
recirculating in this system is less than 20 m3/MWh, and the small usage discharged to the
water treatment plant is 0.1 to 0.3 m3/MWh (EGCSA, 2012, p. 38). If the closed loop
system includes a holding tank to store the water before discharge overboard, then the
EGCS can operate without discharging the treated water for a limited period.
40
Bachelor project
2013
Hybrid EGCS
Figure 18: Hybrid Exhaust Gas Cleaning System – open loop operation (EGCSA, 2012, p. 39)
The hybrid EGCS is a combination of the open and closed system as illustrated in figure
18 (open loop) and 19 (closed loop). Then the open loop system can be used when
operating in open waters where alkalinity is high enough for scrubbing and the closed
system can then be used when in sensitive areas or where alkalinity is too low.
41
Bachelor project
2013
Figure 19: Hybrid Exhaust Gas Cleaning System – closed loop operation (EGCSA, 2012) (EGCSA, 2012, p. 39)
The advantage of the hybrid system is the possibility of switching between open and
closed loop when it suits the purpose. It optimises the chemical use and when fitted with a
holding tank the closed loop system ensures that there is no discharged water in contained
or sensitive areas. It has to be noted that the power to operate this system is higher when
operating in open loop due to the higher amount of water needed in the scrubbing process.
The hybrid system is also the system consisting of most components which increases
weight and the total costs of the system.
42
Bachelor project
2013
Operating and maintaining the wet EGCS
This passage is based on a Clean Marine Hybrid Multistream Exhaust Gas Cleaning
System. Before operation the crew shall be aware of safety procedures and take special
precautions when handling NaOH. NaOH is corrosive and in contact with unprotected eyes
or tissue it can cause blindness, chemical burns or scarring (Clean Marine, 2012, p. 5).
The environment handling NaOH shall not contain aluminium. If NaOH is exposed to
aluminium hydrogen gas is produced which is highly flammable (Clean Marine, 2012, p. 5):
3 H2(g) + 2 Na3AlO3(aq)”
An operation screen layout is shown in figure 20:
Figure 20: Operator screen layout (courtesy of Clean Marine A/S)
The operation screen shows that the system consist of pumps, valves, filters, pipes, air
blowers, sludge tank, holding tank, buffering tank, NaOH tank, pressure and temperature
gauges etc. All these mechanical components and parameters need constant operation,
maintenance and service. The system is designed so it can be controlled if a fail arises
e.g. if one of the sea chest pumps fails or if one of the air blowers controlling backpressure
fails.
43
Bachelor project
2013
The working procedure of the system should be taught to the crew before handling
operation of the system. The reason for doing correct operation is to control the EGCS in
order to (Clean Marine, 2012, p. 13):

Allow safe start up, running operation/synchronizing and shut down

Ensure maximum automated control is reached

Minimize thermal and mechanical stress during start up and shut down

Maximize SOX capturing efficiency with minimum consumed water/power and
NaOH
In general the sequences are controlled from the operator workstation through automatic
start up, operation and shut down. The main operation modes are the open and closed
loop mode:
Open loop
Closed loop
Seawater or fresh water pumped from the Freshwater is circulated in the system with
sea chest is passed through the EGC unit added NaOH to control SOX reduction and
with added NaOH in order to control SOX pH levels. The water circulated is treated in
reduction and pH level if necessary.
the water treatment unit before reintroduced
Some of the washwater is filtered through to the system.
the water treatment unit. If washwater levels As water is saturated more freshwater is
are in excess of the limits allowed in the added to the system while the equal amount
guidelines (see the:” Compliance with the of saturated water is led to the holding tank.
regulation” passage)
Manual control of the components can also be done by local push buttons.
Frequently checks should be done on the system on a daily basis:

Levels of NaOH storage

Sign of vibrations, excessive heat and of any leakages
Maintenance on the system has to be done to keep the system operational and calibration
of the system ensures that the equipment measures correct. Regularly cleaning of sensors
in the system may be required e.g. the PAH sensor (Joel Goodstein, 2013, p. 12).
44
Bachelor project
2013
The dry EGCS
Dry EGCS remove pollutants by the absorption mechanism. Dry EGCS for the marine
industry functions due to a chemical absorption process called chemisorption.
Through this process the SOX is trapped by the chemical reaction which is converting it
into a stable compound.
Figure 21: Principle of a dry EGCS (Alejandro Hombravella, 2011, p. 64)
The principle of dry EGCS is that the exhaust gas enters the absorber sidewise as shown
in figure 21. It then streams horizontally through the bulk layer of the absorbent which is
loaded from the top into the absorber. The exhaust gas is forced to find its way through the
layer due to the outlet. It is constructed as triangle-shaped cascade channels which are
reciprocally closed at the housing wall – forcing the exhaust gas through the absorbent
layer and thereby removing the sulphur dioxide (Alejandro Hombravella, 2011, p. 99). In
the bottom of the EGCS the residue is removed by a conveyor and stored in the vessels
ballast tanks.
Figure 22: Cascade channels (Lodder, 2011) - edited
45
Bachelor project
2013
To make the dry EGCS effective the right absorbent material must be used. Lime based
material such as calcium hydroxide (Ca(OH)2) is used as absorption material. To make the
Ca(OH)2 more effective a larger surface is needed. Therefore the Ca(OH)2 is supplied as
granulate11 with a very high surface to mass ratio in a size range of 2mm to 8mm. Efficient
dry EGCS remove about 99 % of the SOX (EGCSA, 2012, p. 63).
Figure 23: Calcium Hydroxide Granulate - Ca(OH)2 (Jürgens, 2012)
The amount of Ca(OH)2 used in the dry scrubbing process must be regulated according to
engine load, the amount of sulphur in the fuel and the required SOX reduction. Usually the
amount of Ca(OH)2 used is 40 kg/MWh12 based on a marine engine operating on HFO
with a 2.7 % sulphur content (Lloyd's Register, 2012, p. 27). The density of the Ca(OH)2 is
800 kg/m3 which gives a usage of 0.05 m3/MWh. Hence is a vessel with 20 MW power
using 19.2 tonnes Ca(OH)2 based on 24 hours operation.
Figure 24: Chemisorption (EGCSA, 2012, p. 53)
The chemisorption process in a dry EGCS with Ca(OH)2 undergoes different reactions but
all of them end up with turning into a stable compound like gypsum. The reaction with SO2
and Ca(OH)2 forms calcium sulphite and water (CaSO3 + H2O).The sulphite is then
11
12
From now on the calcium hydroxide granulate is referred to as “Ca(OH)2”
Note that Couple-systems claims another usage – see that in passage: ”Discussion of Ca(OH)2 usage”
46
Bachelor project
2013
oxidised by the exhaust gas to form calcium sulphate (2CaSO 4) and then hydrated in the
exhaust gas to form calcium sulphate dihydrate (CaSO4·2H2O) which is gypsum.
The SO3 forms gypsum as well without the need for further oxidisation. The reaction only
needs Ca(OH)2 and water to form calcium sulphate dihydrate (CaSO4·2H2O). Note that the
produced gypsum is not clean enough13 to use directly as e.g. building material and must
undergo further processes e.g. a power plant desulphurization system.
Figure 25: Dry Couple System in combination with SCR (Couple system, p. 20)
The dry system in figure 25 is in combination with a Selective Catalytic Reduction (SCR) in
order to reduce NOX. The process in this system is to let the exhaust gas stream through
the silo where the Ca(OH)2 is added to absorb SOX. Then convert it into a stable
compound which is gypsum. Bypass operation is available for areas with no sulphur
requirements. This option saves Ca(OH)2 and it also saves the vessel from generating
unnecessary wastes to be stored and discharged from the residue tanks.
The exhaust gas is let into the dry EGCS after the turbocharger thus is the exhaust gas
temperature approximately 240oC to 350oC14. Due to the temperature the only thing
required for the desulphurization is the Ca(OH)2 and electrical energy to power the load
and discharge system, the conveyor to remove the residue, the optional exhaust gas fan to
13
14
The quality is too low
Depending on engine type
47
Bachelor project
2013
handle back pressure issues and the electrical control of the system. Furthermore the dry
EGCS functions as a silencer lowering the noise caused by the engine.
The exhaust gas temperature is not reduced during the dry scrubbing and therefore the
gas volume remains the same throughout the process. In accordance to this a suitable
sized EGCS volume must be used in order to reduce the gas flow which enables impact
and filter trapping to occur so as to remove PM. The problem with the high temperature is
that removal of other secondary PM is reduced. Further development of sections for the
dry EGCS is undergoing to address this problem (EGCSA, 2012, p. 63). Compared to the
temperature loss during wet scrubbing, the temperature is significantly higher after the dry
EGCS without any additional added energy. It gives the option of combining NOX reduction
using an SCR system after the EGCS that requires the high temperature (see:“Selective
Catalytic Reduction (SCR)” passage). Note that on engines with low combustion
temperatures additional heating is required in order for the SCR to be efficient. E.g. slow
crosshead engines.
48
Bachelor project
2013
Discussion of Ca(OH)2 usage
The data used in this project regarding the amount of Ca(OH)2 needed in a dry EGCS
might be misleading. The reason is the different claimed usage from both, Lloyd’s
Register, Caterpillar and Couple-Systems.
The different Ca(OH)2 usage is:
1. 40 kg/MWh at 2.7 % to 0.1 % sulphur content (Lloyd's Register, 2012, p. 27)
2. 30 kg/MWh at 3.0 % to 0,1 % sulphur content (Larsen, 2012, p. 18)
3. Specific fuel oil consumption of 200g/kWh and 16 kg/MWh at 2.7 % sulphur to ?
(Couple, 2013)
The different values might all be accurate since unknown factors from the sources aren’t
available in this project. The unknown factors are e.g. the specific fuel oil consumption, the
quality of the used Ca(OH)2 and the scrubbed exhaust gas SO2/CO215 ratio value. The
most obvious difference is between the data from Lloyd’s Register and Couple-Systems.
The reason for the significant difference is not clear. In accordance to this the low amount
claimed by Couple-Systems may be different due to the current required sulphur content in
fuel oil of 1 % found in Annex VI Regulation 14. The lower sulphur content required, the
more Ca(OH)2 is needed to remove SOX. If the data from Couple-Systems is based on
reducing the SOX emissions to those equivalent to fuel oil of 1 % instead of 0.1 % that
could be the explanation. Before purchasing the dry EGCS this should be cleared to avoid
misunderstandings. It is very important regarding the need for storage space, time at sea
and the economy.
15
It is explained in the: “Compliance with the regulation” passage
49
Bachelor project
2013
Operating and maintaining the dry EGCS
Since no information about procedures and operation of a dry EGCS was obtained to
realize this project, ordinary operation and maintenance procedures are assumed. As it is
for the wet system the crew shall be aware of safety procedures before operation
regarding how to handle the system in case of failures and bunkering the Ca(OH)2. The
Ca(OH)2
must be stored in a dry environment/container in order to avoid humidity
problems which may cause the lime to stick together i.e. it gives problems with the
Ca(OH)2 clogging the system. Regularly checks of the storage facilities in order to avoid
the problem are advised.
Figure 26: Dry EGCS (Courtesy Couple-Systems)
As illustrated on figure 26 the dry EGCS consist of mechanical components like valves, air
blowers, pipes and storage etc. Other dry EGCS have conveyor belts to move the lime
around the system. The system also consists of measuring equipment to control the
SO2/CO216 ratio and temperature indicators. All these mechanical components and
parameters need constant operation maintenance, service and calibration. Crew needs to
be trained to handle the system and know the operation parameters to ensure correct
handling and safety.
16
It is explained in the: “Compliance with the regulation” passage
50
Bachelor project
2013
Summary of: “The EGCS”
The main technical differences between the wet and dry EGCS were cleared in this
passage.
Note the following for further reading:

The wet EGCS uses water to remove SOX and consists of the open loop, closed
loop and a combination of the two – the hybrid EGCS

The open loop is a one way process discharging the used washwater overboard
which could be a problem if operating in sensitive areas

The closed loop and hybrid17 EGCS consume aqueous sodium hydroxide (NaOH)
also known as caustic soda to operate in a closed loop system without any
discharge overboard for a limited time

The dry EGCS consumes calcium hydroxide granulate (Ca(OH)2) which has to be
stored aboard

The exhaust gas temperature loss is minimal during dry scrubbing

The closed loop, the hybrid and the dry EGCS is the suitable choice if the vessel is
operating in sensitive areas due to the interdiction to discharge overboard
17
When operating in closed loop
51
Bachelor project
2013
4. Dealing with nitrogen oxides - NOX
Selective Catalytic Reduction (SCR)
A further decrease of nitrogen oxides (NOX) levels from marine diesel engines in ECA is
scheduled for 1th January 2016 due to regulation 13 of MARPOL Annex VI. A review of
the enabling technologies will set the limit according to the third step of TIER III where NOX
emissions must be no more than 2 to 2.3 g/kWh depending on engine speed (EGCSA,
2012, p. 64). It is however only required on newly build vessels or reconstructing.
SCR converts NOX into water (H2O) and nitrogen (N2) by a stoichiometrically reaction
between NOX and ammonia or urea to form Nitrogen (N2) and water vapour (H2O) (Couple
system, p. 18).
Figure 27: Schematic structure of Couple Systems SCR technology (Couple system)
The temperature in the catalyst must be high enough (above 300 oC) before the reaction is
sufficient which is not always the case. In four strokes medium and high speed engines the
combustion temperature is above 300oC which is why SCR systems are normally
equipped on those types of engines. Engines operating on low load and slow crosshead
engines have lower exhaust temperatures which makes it a problem to use SCR. SCR has
52
Bachelor project
2013
been equipped on a few slow crosshead engines, but the reactor has been placed
upstream of the turbocharger in order to expose the catalyst to the highest temperature
available. Additional heating may be required e.g. install a burner to increase the
temperature after the turbocharger (EGCSA, 2012, p. 64). The problem with placing the
SCR before the EGCS on engines operating on HFO is that the SCR process is sensitive
to the exposure of SOX. It can react with the ammonia (NH3) to ammonium hydrogen
sulphate (NH4HSO4) and it can clog the surface in the catalyst and reduce the efficiency of
the SCR (Couple system, p. 18). Additional development of the SCR is required to solve
the SOX problem.
Figure 28: Catalyst element fouling (Lloyd's Register, 2012, p. 33)
A combination of EGCS and SCR is therefore an issue of the temperature of the exhaust
gas. If it is too low additional heating can increase the temperature to the SCR but requires
energy. Hence is the combination of SCR currently best suited for dry EGCS due to the
minimal loss of exhaust gas temperature compared to the wet EGCS.
53
Bachelor project
2013
Exhaust gas recirculation system (EGR)
As explained in the: “Composition of the exhaust gas” passage there is excess oxygen
during combustion in a diesel engine. During a combustion process a lot of reactions
occur, but when dealing with NOX it is a reaction between nitrogen and oxygen.
The rates of the reactions are highly influenced by the combustion temperature. At 1200 oC
the formation of NOX is considerable and above 1500oC it rises exponentially. Thus is the
combustion temperature, the amount of excess air/oxygen in a diesel engine, and the time
that the exhaust gas is exposed to the high temperature significant when dealing with NOX
emission.
Figure 29: The combustion temperatures influence on NOX emission (Egeberg, 2009)
A way to decrease the combustion temperature and the amount of oxygen is by
recirculating some of the exhaust gas into the combustion chamber by using an EGR
system. It decreases oxygen in the combustion mixture and increases its heat capacity
and thereby reduces the peak combustion temperature.
EGR is known to reduce NOX in the automobile market, but is relatively new to vessels. A
test engine by Man Diesel & Turbo has reached tier lll NOX levels by recirculating 40 % of
the exhaust gas (Lloyd's Register, 2012, p. 36).
54
Bachelor project
2013
Figure 30: An EGR system arrangement of a two-stroke low-speed engine (image courtesy of MAN Diesel &
Turbo) (Lloyd's Register, 2012)
The main components of an EGR system are illustrated in figure 30:

A high pressure EGCS which are fitted before the turbocharger

A cooler and water mist catcher to cool down the recirculated gas

A blower to increase the recirculated exhaust gas pressure before being let in to the
scavenge air

Valves to control the system
The recirculated exhaust gas is scrubbed in order to remove the SOX and PM. It is done to
reduce fouling and prevent corrosion of EGR and engine components. The EGCS system
is normally a closed loop system with the included buffer tank with fresh water, a NaOH
chemical device and a water treatment plant.
A first generation MAN EGR was installed on M.V Alexander Maersk to undergo trials.
Corrosion issues of EGR components such as cooler casing and blowers were
experienced. It was reported that operating on 3.0 % sulphur HFO a reduction of NOX
exceeded 50 % with an exhaust gas recirculation rate of 20 %. MAN is now constructing a
second generation EGR system and is planning a 40 % exhaust gas recirculation rate in
55
Bachelor project
2013
order to comply with Tier lll (Lloyd's Register, 2012, p. 37). The advantage of the EGR
system is that operations on low load and the sulphur content in fuel oil is not constraining
factors compared to SCR. However EGR is not without problems because it can result in
increased CO and PM emissions which can be controlled by using other techniques such
as adding water to the fuel in order to reach the right balance between NOX, CO and PM.
Failure of the EGCS system in the EGR can cause accelerated engine wear and the need
for more maintenance if the EGCS fails to clean and cool the exhaust gas to the required
levels. EGR system which malfunctions or run with deviations from normal operation can
decrease engine efficiency significantly and increase CO and PM (Lloyd's Register, 2012,
p. 37). The EGR system is suitable for both the dry and wet EGCS. If wet EGCS
manufacturers install a standardised outlet to the EGR system, the complexity of the EGR
arrangement is reduced.
5. Supplying and disposal of the
different consumables and residues
Wet EGCS
In both the open and closed loop wet EGCS the residue from the treatment plant has to be
stored aboard. A sludge tank at 0.5 m3/MWh is typically recommended by the wet EGCS
manufacturers (Lloyd's Register, 2012, p. 24). It is a relatively minor problem due to the
small space needed. It is not allowed to incinerate the residue. Hence it must be landed
ashore and disposed of appropriately like the other residues from the sludge tanks e.g. oil
residue.
The closed loop and the hybrid EGCS uses NaOH to control alkalinity of the recirculated
water at a rate of approximately 15 L/MWh if HFO with sulphur content of 2.7 % is
scrubbed to the equivalent of 0.1 %. This amount is also a minor problem compared to the
total system space needed. NaOH is a normal produced chemical which are easy to obtain
and is typically used as a 50 % solution in wet EGCS (EGCSA, 2012, p. 40).
56
Bachelor project
2013
Dry EGCS
The Ca(OH)2 similar to the substance used in the dry EGCS is used in large scale in FGD
systems on power plants. Power plants, tough, are placed at the same location at all times
thus making it easier to obtain Ca(OH)2 from a permanent supplier. In accordance to this
FGD systems on power plants dissolves the Ca(OH)2 using water which then is used to
scrub the flue gas. Thereby do they not need the Ca(OH)2 delivered as granulate which is
used in the dry EGCS on vessels. MAN Diesel shows in a presentation from 2011 (Figure
31) the supply partners that can deliver new and receive the used Ca(OH)2 for vessels in
Europe.
Figure 31: Ca(OH)2 supply partners (Lodder, 2011)
The Ca(OH)2 is not a common storage product and has to be ordered in advance to be
ready in the selected bunker port. Ca(OH)2 usage in the dry EGCS is approximately 19.2
tonnes/day based on a 20 MW engine operating on HFO with 2.7 % sulphur content in
order to reduce SOX emissions equivalent to fuel with 0.1 % sulphur content (Lloyd's
Register, 2012, p. 27). The density of the Ca(OH)2 is approximately 800 kg/m3 which gives
the space needed for storage on a 30 day basis: 18
18
Note that Couple-systems claims another usage – see that in passage: ”Discussion of Ca(OH)2 usage”
57
Bachelor project
2013
It requires a large storage facility to handle the huge amount and weight of the Ca(OH)2
and the used Ca(OH)2 which requires approximately the same storage space. Due to this
the limits on the size of storage available and the days on open seas makes it difficult to
implement the dry EGCS on vessels sailing for longer periods. It is because of the problem
with bunkering new Ca(OH)2 at some of the ports. Currently it is not possible to get new
Ca(OH)2 on open seas only at the ports. Couple-Systems assure that the Ca(OH)2 is
available worldwide (Couple, 2013):
“A world-wide availability of the granulate is ensured by Couple Systems.
Production licences for additional capacity can be assigned geographically,
close to the global bunker ports where the merchant ships are supplied with
granulate. Both power plants and lime plants are located worldwide within a
radius of 200 km from all major ports.”
The Ca(OH)2 is available in bags, can be in a special container or by using silo trucks as
shown in figure 32.
Figure 32: Ca(OH)2 supply and disposal (Couple, 2013)
The used Ca(OH)2 is disposed the same way as it is supplied and it can be used by
different facilities e.g. desulphurization on power plants, cement plants, steel plants etc.
Figure 33: Disposal facilities (Couple, 2013)
Couple-systems claims that the disposal of the used Ca(OH)2 is on a cost neutral basis
due to the functional use of the substance.
58
Bachelor project
2013
6. Compliance with the regulation
Both the wet and the dry EGCS can follow the (Lloyd's Register, 2012, p. 42):
“MEPC 184(59) – 2009 Guidelines for Exhaust Gas Cleaning Systems”
In order to meet the requirements from MARPOL Annex VI regulation 4 which allow the
use of EGCS instead of low sulphur fuel oil to comply with regulation 14. The guideline for
EGCS specifies the requirements for how certification, in-service verification and test of
EGCS are done. It is briefly explained in the following passage:
Since it is only a guideline IMO cannot claim or enforce that it is followed. The
responsibility rests with the vessels flag state and thus the national government. The
guidelines are made as a help to show additional evidence on the performance of the
EGCS, to an additional flag administration if the vessels e.g. changes flag.
The guideline allows measuring the SO2/CO2 ratio to enable compliance with regulation 4.
That is because the majority of SOX in the exhaust gas is SO2 and it is almost entirely
derived from the sulphur content in the fuel. The majority of CO2 emissions in the exhaust
gas are also almost entirely derived from the fuel. This leaves the opportunity to measure
the sulphur content in the fuel relatively easy by measuring the SO2 and CO2 emissions in
the exhaust gas. Then other engine parameters such as engine speed and fuel
consumption is not needed (Lloyd's Register, 2012, p. 42). Thereby is the complexity of
establishing a monitoring system relatively reduced and thus is the price of the system
also reduced. The guidelines enable compliance with regulation 4 to be demonstrated if
the SO2/CO2 ratio in figure 34 is followed in regard of the fuel oil sulphur content allowed.
Figure 34: Fuel oil sulphur content and corresponding SO2/CO2 ratio (Lloyd's Register, 2012, p. 42)
A vessel having EGCS installed will require a SOX Emission Compliance Plan (SECP).
SECP is prepared by the vessel operator and it must show how the vessel will ensure
59
Bachelor project
2013
compliance with Annex VI regulation 4. As a help in the guidelines there are two schemes
available to give an alternative method to ensure that the EGCS are in compliance with
Annex VI regulation 4. The schemes are called A and B.
Scheme A (Lloyd's Register, 2012, p. 43):
Scheme A is used as an initial certification of the EGCS. The EGCS must have a SOX
Emissions Compliance Certificate (SECC). It can be done in a test bed or when installed
aboard the vessel. It certifies that the EGCS can reduce SOX emission as described in
Annex VI regulation 14. An approved EGCS has an EGCS – Technical Manual (ETM-A)
where the relevant components and operating parameters for the EGCS is found. If the
system is according to the (ETM-A) then is the EGCS compliant with Annex VI regulation
4. The guidelines also approves identically serially produced units with the same design
but with different capacity to be approved without the need for repeat testing on each unit.
There are also demands in the certification to ensure compliance when the EGCS are in
service by continuously monitoring some operational parameters. It is also recommended
to do daily checks on the emissions. Parameters in a wet EGCS which have to be
monitored are e.g.

Scrubbing water pressure and flow rate

Exhaust gas pressure and temperature before the EGCS

The pressure and temperature drop across the EGCS

A record of chemical consumption
To keep track of these measurements an approved On-board Monitoring Manual (OMM) is
required. It is also required that the vessels position and standard time is recorded and
stored for at least 18 months, ready for inspection to confirm compliance. Maintenance,
service records and component adjustments must be kept in the EGC record book.
60
Bachelor project
2013
Scheme B (Lloyd's Register, 2012, p. 44):
Scheme B is ensuring compliance with Annex VI regulation 4 by using a continuously
emission monitoring system. The emission monitoring system is required to show the
SO2/CO2 ratio in the scrubbed exhaust gas and that it complies with Annex VI regulation 4.
With emission monitoring system installed the need for initial certification of the EGCS is
not necessary, but the emission monitoring system must be approved. It is subject to
periodic surveys and an initial survey at installation. Under scheme B the On-board
Monitoring System (OMM) shall contain the same records as under scheme A. An EGCS –
Technical Manual (ETM-B) must also be approved and shall contain the same as scheme
A, but also show what action is to be taken if the SO 2/CO2 ratio is exceeded. Like under
scheme A, maintenance, service records and component adjustments must be kept in the
EGC record book.
Figure 35: EGCS documents required in the guidelines (Lloyd's Register, 2012, p. 43)
Washwater (Lloyd's Register, 2012, p. 44):
Regardless of the schemes the washwater discharged from the wet EGCS systems must
be continuously monitored. These parameters must be logged against the time and the
vessels position e.g.

pH to measure the waters acidity

Polycyclic aromatic hydrocarbons (PAH)

PM and oil
A test of the nitrate content is also required at each renewal survey.
EGCS using chemical must undergo a specific assessment to determine if additional
washwater criteria is required.
The washwater residue must not be incinerated and therefore it has to be stored aboard in
sludge tanks ready for proper disposal ashore.
61
Bachelor project
2013
Commenting compliance of wet and dry systems
Using the guidelines to make sure the EGCS are in compliance with Annex VI regulation 4
is useful for the different EGCS manufacturers. It is because they know what parameters
and limits to measure without using all their resources on each flag states different rules
and regulations. The wet systems have all the parameters needed in the guidelines so
they know what to measure and keep track of. It is up to each manufacturer to determine if
they want to follow the guidelines and if they want to use scheme A or B.
The dry EGCS can also use the guidelines according to Couple-Systems homepage
(Couple, 2013) where a dry EGCS was installed on MV Timbus (3.6 MW) and approved
using scheme B. Although nothing about discharge of used Ca(OH)2 is found in the
guidelines. It is assumed without following up on other annexes that it is prohibited to
dump used Ca(OH)2 in the ocean. It would also be a waste since the used Ca(OH)2 is
useful for e.g. power plants.
According to the EGCSA19 only WÄRTSILÄ/HAMWORTHY has obtained a scheme A
approval (EGCSA, 2012, p. 99).
19
Exhaust Gas Cleaning System Association
62
Bachelor project
2013
7. Person gallery
The gallery is based on email correspondence and interview with relevant people in
account of this project. The reason for contacting these people was to get answers to
some issues and confirm some of the aspects in this project. Empirical knowledge is also
obtained on operation and maintenance from Flue Gas Desulphurization (FGD) systems
on power plants which can be compared to EGCS on vessels. All of this is to widen the
knowledge in this project. The qualitative method was used to get the exact answer to the
issues.
For further information the emails are found in appendix 13.1 to 13.4. Note that they are
not in English. The most important from the answers is translated, commented or
discussed in this gallery.
Alf Helge Torkelsen, Senior Sales Engineer at Clean Marine A/S
(Found in appendix 13.1. From page 81)
Any unforeseen events during implementation of EGCS?
During implementation of EGCS events has occurred that would be called unforeseen.
Clean Marine was well prepared for it due to the comprehensive implementation there is of
the relative new EGCS.
Typical errors and lifetime of the system?
EGCS is still too new to tell anything about typical errors on the system due to the limited
running hours. The system consists of a large scale of mechanical components like air
blowers, valves, pumps and electronic sensors which do not last forever.
The lifetime of an EGCS is made so it fits the rest of the vessels engine installations.
What service must be made on the system?
Clean Marine delivers the EGCS with a manual in the documentation explaining the
needed service requirements. In general there are some filters on the exhaust gas
equipment and in the water system which must be changed.
A calibration procedure on the analysis equipment is also needed. The system can be
remotely controlled from our office but once a year service on the equipment is needed.
63
Bachelor project
2013
How is the operation on the vessels and main engine affected by EGCS?
Operations of the vessel are not affected on a larger scale. The system is self-regulating
and doesn’t need anything else than being turned on or off. The ordering of NaOH has to
be planned and the crew has to ensure enough of it for the whole trip. In general there is
no need for further crew in the machine. Clean Marine will teach how to operate the
system and the chief should point out one or two crew members who will be specialised in
the system. The daily work on the equipment will just be a part of the daily routine by the
machine crew.
Can SCR be useful on the wet EGCS in order to handle NOX emission?
A solution of SCR in combination with the wet EGCS has its challenges. First of all, the
temperature after the wet EGC unit is too low for the SCR to function properly. The other
problem is the SOX level in the exhaust gas which the catalyst elements cannot withstand.
Although manufacturers claim to have developed a catalyst that can handle SOX there is
not enough documentation and test on it yet. If the problem is solved the SCR can be
mounted before the wet EGCS and then it would be a viable solution.
Discussion of Alf Helge Thorkelsen’s answers
The answers from Alf Helge Thorkelsen are considered to be reliable because he is a
professional working and following the business. The answer he has given supports the
following studies of EGCS in this project. When he says that the electronic equipment
does not last forever, an article from March 2013 in the Danish Marine Engineer magazine
(Maskinmesteren) is agreeing with his answer due to problems with PAH sensors on
EGCS (Joel Goodstein, 2013).
Even though the answers seem to be reliable they have to be seen with a sceptical eye
since there is competition between the EGCS manufacturers. He thinks that the
temperature after a dry EGCS is insufficient for an SCR to function properly. He is not
specialised in dry EGCS and thus is that answer not considered valid or reliable.
64
Bachelor project
2013
Max Bøgh Frederiksen, Mechanical and Technical Engineer
(Maskinmester) at Esbjergværket (power plant)
Phone interview with Max Bøgh Frederiksen 21th May 2013:
The questions asked at the interview were regarding operation, service and failure on the
wet FGD system at Esbjergværket and distribution of the residue from the system.
According to Max their system was very reliable.
In brief details he said:

Normal operation and maintenance is needed at the system regarding mechanical
components like filters, pumps, valves etc.

They have never had major breakdowns on the system

Every third year the system needed to be cleaned since the lime connections from
the storage to the EGC unit gets coated

Although the EGCS is made of stainless steel it also needs glass and rubber
coatings inside due to the wet acidic atmosphere inside the EGCS. Thus is the
coating on the EGC unit controlled at the same time as it is cleaned.

The water treatment plant is using a lot of resources because the electronic
equipment needs cleaning regularly

They receive mixed gypsum residue from other power plants e.g. Studstrupværket
where they have a dry FGD producing what is known as (TASP). In the FGD
system at Esbjergværket, the can use the TASP as an absorbent product. He was
sure that they could use the residue from dry scrubbing aboard vessels in their
process.

The gypsum produced in the FGD system is not total clean gypsum but they have
strict standards to comply with due to their distribution of the gypsum to a gypsum
company
Commentary
Max Bøgh Frederiksen is educated in engineering and is specialised in the FGD system at
Esbjergværket. The answers are considered reliable due to his special interest in FGD and
there is no commercial interest involved. Even though he believed that the used Ca(OH)2
from dry EGCS from vessels could be used at Esbjergværket it is not considered fully
documented.
65
Bachelor project
2013
Viggo Rahbek Warming, Operation Engineer at Studstrupværket (power
plant)
Phone and email correspondence:
The questions asked at the interview were regarding operation, service and failure on the
dry FGD system and distribution of the residue from the system at Studstrupværket.
In brief details he said and wrote to the questions:

The dry FGD at Studstrupværket is reliable and the produced product is called
TASP which is used at Esbjergværket

Time based maintenance is done on the mechanical components which prevents
major breakdowns

The mixing tanks for the lime and water is cleaned every year

The DeNOX system is cleaned once every day using a soot blower

The catalyst in the DeNOX is normally consisting of two layer and after normally two
years another layer is installed in order to extend the catalyst lifetime for minimum
another year.
Commentary
Viggo Rahbek Warming has great experience with the FGD system at Studstrupværket
and there is no commercial interest involved. Hence, is his answers considered reliable.
His answer was brief, but he gave the impression that the dry FGD system was very
reliable and only needed normal maintenance and operation.
66
Bachelor project
2013
Anders Rooma Nielsen, Catalyst & Process Specialist at Haldor Topsøe A/S
Anders has a PhD in chemical engineering and he answered questions about NOX
reduction:
Is a catalyst developed that can withstand the high SOX level when operating on
HFO?
Haldor Topsøe can make a catalyst with low vanadium content that ensures a lower SO2
oxidation. Conditions that is difficult for the catalyst to withstand is high SOX level and low
temperatures under 300 degrees since there is a risk of ammonium bisulphate blocking
the elements in the catalyst. The only thing to do in these cases is to regenerate the
catalyst by heating it up until about 350 degrees where the ammonium bisulphate will
evaporate from the catalyst. It can be done by installing a burner to heat up the exhaust
gas before the catalyst.
Are catalysts with the opportunity of changing the element developed so it can be
changed in case of failure when operating on HFO and what about soot blowing?
The elements can be changed of course, but it is expensive. Soot-blowers are used on
vessels by air nozzles installed at each catalyst layer. But it cannot remove all the
ammonium bisulphate. Heating is required.
Commentary
Anders Rooma Nielsen is considered very reliable due to his degree in chemical
engineering and his work at Haldor Topsøe where he is catalyst and process specialist.
Even though he does not answer clearly he explains how to handle the problem with
ammonium bisulphate blocking the elements in the catalyst.
67
Bachelor project
2013
Jesper Arvidson, Low Speed Engineering / Operation dept. at MAN Diesel &
Turbo
MAN Diesel & Turbo was contacted regarding dry scrubbing due to the failed attempt to
contact Couple-Systems where there was no response. MAN Diesel & Turbo is
cooperating with Couple-Systems. Jesper answered in great details and therefore a brief
summary of his answers is listed:

Dry EGCS can be used at both 2 and 4 strokes engines

A lot of Ca(OH)2 is used in the dry EGCS and the residue has to be stored as well.
A vessel with a larger engine power installed has to get a lot of Ca(OH)2 bunkered
and it would take several trucks causing logistic problems

That’s why we only see the use of dry EGCS on vessels with limited engine size
and small sea routes with the possibility of arriving at the same ports. Hence a fixed
delivery system of Ca(OH)2 can be established

In some cases additional heating is required for the SCR to work properly in
combination with dry EGCS

It is possible to get the Ca(OH)2 in Canada but it is not entirely clear if it can be
delivered worldwide in the proper granulate size even though it is a well-known
industrial product

The system is basically consisting of air blowers, screw conveyors which needs
regularly maintenance

The newest version of MAN developed EGR is showing successful results on an
Maersk vessel
Discussion of Jesper Arvidson’s answers
Jesper Arvidson has knowledge about dry EGCS through his work at MAN Diesel which
makes his explanations a reliable source. He uses data from Couple-System which can be
discussing if they are accurate about the Ca(OH)2 usage. Jesper has though confirmed
some aspects of the studies of dry EGCS in this project which was very useful.
68
Bachelor project
2013
Discussing the Person Gallery
The information given by the interviewees can certainly be considered reliable material
due to their professions and backgrounds. This was why they were contacted in order to
confirm and widen the knowledge in this project.
The broader picture from the interviews is that there are still some challenges with EGCS
even though the land based units are very reliable. Normal operation and maintenance on
the systems are all that is required, but since the EGCS is still relatively new on vessels
implementation problems may occur. FGD systems requirement for cleaning and control of
coating inside pipes and the EGC unit every 1 or 3 year may be referred to the EGCS on
vessels as well to extend the EGCS lifetime. The problem with combining SCR in
combination with the wet EGCS due to SOX is a known problem. It is still unanswered
although alternative solutions can be implemented in order to comply with TIER III in 2016.
EGR is maybe a better solution for the wet EGCS and the newest version of MAN Diesel
EGR system has shown good results. SCR may seem as a better solution for the dry
EGCS, but on engines with low combustion temperature like two-stroke low speed
engines, additional heating may be required. According to MAN Diesel the dry EGCS only
seems possible on vessels with limited engine size and small sea routes. In accordance to
this the vessels should arrive at the same ports due to logistics problems caused by the
Ca(OH)2 usage. If a proper sea route and delivery system is established the vessel owner
have to consider if the vessel is supposed to operate under these conditions for the full
lifetime of the vessel. A hypothetical situation where the conditions changes or if the vessel
is sold could be a problem due to longer sea routes or operation in ports without any
realistic Ca(OH)2 suppliers.
69
Bachelor project
2013
8. Table comparing wet and dry EGCS
Data from (Lloyd's Register, 2012, p. 29)
Wet - open loop
Type
Operation in fresh
Only in areas with
water
sufficient alkalinity
Operation without
discharge to sea
Wet – closed loop
Wet - hybrid
Dry EGCS
Yes
Yes – in closed loop
Yes
Yes – For a limited time depending on the size of
No
Yes
the washwater holding tank
≈200t
Weight. Typical
values for a 20MW
EGCS
30-55t
30-55t
(Including Ca(OH)2
(Excluding washwater
(Excluding washwater system, treatment
stored adjacent to the
system and
equipment, washwater, processing tank and
absorber but excluding
treatment equipment)
washwater holding tank)
additional Ca(OH)2
storage)
Power
consumption in %
1–2%
0.5 – 2 %
(Depending on
whether it is
operating in open or
closed loop mode)
0.5 – 1 %
of max. power
Consumables
No
(Chemical)
Sodium hydroxide – NaOH (50 % solution)
Compatibility with
Yes, provided the EGC unit is installed after the waste heat recovery system,
waste heat
due to the cooling in the EGCS. The waste heat recovery system have to be
recovery system
fitted after SCR (optional)
0.15 - 0.20 %
Calcium hydroxide
granules - Ca(OH)2
Yes. Can be placed
before or after the waste
heat recovery system, but
after SCR (optional)
Additional need for
operation or
No additional needs. It will be part of the daily routine by the crew
maintenance
Maximum engine
power with EGCS
Unlimited according to
Unlimited depending on the manufacturer (EGCSA, 2012, pp. 94,95)
Couple-Systems
(EGCSA, 2012, p. 95)
installed
Yes – If the SCR is placed
after the EGCS. In some
Compatibility with
SCR system
Yes – If the SCR is placed after the EGCS and the exhaust gas is reheated to
cases the exhaust gas
reach sufficient SCR temperature
needs reheating in order
to reach sufficient SCR
temperature
Compatibility
with
Yes
EGR system
70
Type
Bachelor project
Wet - open loop
Wet – closed loop
2013
Wet - hybrid
Dry EGCS
% Particulate
matter removal
From 60 to 90 % depending on design and manufacturer
(EGCSA, 2012, pp.
80 % according to
Couple-system
92,93)
Maximum % fuel
sulphur to
achieve equivalent
Standard 3.5 %
Max 4.5 % (Realistic maximum)
5%
of 0.1% (EGCSA,
2012, pp. 92,93)
Tested on vessels?
Yes
Yes - one
Scheme A certified
Yes - WÄRTSILÄ/HAMWORTHY (EGCSA, 2012, p. 99)
NO
Scheme B certified
Yes
Yes
Weight
The weight between the wet and dry EGCS is significant. Note that the weight of the wet
EGCS increases when the NaOH storage tank, processing and holding storage tank is
filled. The difference is the structure of the systems where the wet EGCS can store most of
their weight in tanks in the lower part of the vessel. The weight of the dry EGCS is installed
in the relative high part of the vessel. Thus can the vertical centre of gravity be changed in
a more negative way when implementing the dry EGCS compared to the wet EGCS. In
account to this a retrofit system is usually placed in the higher part of the vessel since
there is no available space in the lower parts of the vessel. Thus is a revision of the
vessels stability manual a necessity (Lloyd's Register, 2012, p. 28).
Particulate matter removal
PM is removed in the EGCS either by being trapped in the washwater droplets or by
absorption in the dry EGCS. The EGCS has proved to be effective to remove PM –
between 60 to 90 %. The EGCS can handle any future regulations on PM emission if the
demand is lower than what the EGCS can remove.
71
Bachelor project
2013
9. Payback period regarding EGCS
A budgetary quote from Couple-Systems was never received during this project and
therefore the data from a MAN Diesel presentation is used to compare the wet and dry
EGCS. When investing in an EGCS it is difficult to calculate the payback period accurately
due to the unknown future price on fuel oil. The main influences on the payback period in
regard of EGCS are the difference in fuel prices and the annual operation hours. MAN
Diesel has calculated the payback period in a presentation from 2011 showing the
payback period in relation to the fuel price gap when investing in the dry EGCS.
Figure 36: Payback time of the dry EGCS from Couple-Systems according to MAN Diesel (Lodder, 2011)
According to MAN Diesel, the payback period of the dry EGCS is under two years if the
price difference is above either
100 to 160$20. When the price gap is under 75$ it is no
longer considered a profitable investment regarding the payback period.
A budgetary quote from 2011 on a wet hybrid EGCS was obtained during this project on a
bulk carrier with 24.11 MW power installed. The manufacturer is confidential and therefore
the company is not revealed in this project. A simple payback period in figure 37 is
calculated from the obtained data which can be found in appendix 13.5. It is assumed that
there are no major expenses due to breakdown on the system and no additional operating
costs.
20
The difference between the two calculations is unknown in this project. Maybe it is because one is for the
main engine, the other is for the auxiliary engine or a combination of them both.
72
Bachelor project
2013
Figure 37: Wet EGCS payback years (own archive)
According to data from the budgetary quote the simple payback period is under two years
already around a fuel oil price gap at 80$. It is slightly better than the calculations on the
dry system from MAN Diesel, but the data from their calculations is unknown. Each vessel
will have to do its own calculation in regard of estimated fuel oil prices, vessel type,
specific fuel oil consumption, operation costs, average engine load, operation hours and
time in ECA. What is most important regarding investing in EGCS is the annual money
saved due to the price difference on fuel oil, annual operation costs and the investing price
of the EGCS.
According to bunkerworld.com on 29th May 2013 the fuel oil prices in Rotterdam are:
HFO380 = 587$
HFO180 = 609$
LSMDO = 864$
That leaves a price gap at either: 864 – 587 = 277$ or 864 – 609 = 255$
According to the conditions in the calculations above it is currently a profitable investment
regarding the payback period since it is under or almost one year which is a short payback
period. When the price gap is under 70 $ the payback period is
2.4 years. When the
price gap is below 70 $ the payback years rises exponentially and it is not considered a
profitable investment.
The calculations might be optimistic due to the unforeseen errors that may occur when
implementing a new EGCS and it is based on the economical HFO that not all vessels are
operating on. Also note the commercial interest by the manufacturers offering a fast
payback period. Thus should these calculations only be used as a guideline.
73
Bachelor project
2013
10. Conclusion
The essential in this project was to analyse the sustainability of the wet and dry EGCS and
compare them against each other regarding the future requirements and regulations.
According to the EGCS manufacturers all the systems can remove SOX emissions
according to the equivalent fuel oil sulphur content as described in MARPOL Annex VI
regulation 14. The next important date in the marine industry is the 1th January 2015
where the maximum allowed sulphur content in fuel oil is set to 0.1 % inside ECA. The wet
and dry EGCS have both been successful in removing SOX to the equivalent of 0.1 %
sulphur content in fuel oil. The EGCS has proved to be effective to remove PM. The dry
EGCS can remove 80 % according to Couple-Systems and the wet EGCS removes
between 60 to 90 % PM. The EGCS can handle any future regulations on PM emission if
the limit is set under the capability of what the EGCS can remove.
A budgetary quote from Couple-Systems (dry EGCS manufacturer) was never received
during this project. Thus it is not considered reliable to conclude if it is the wet or dry
EGCS that is the best investment. But the main factor when investing in EGCS is the
annual money saved due to the fuel oil price difference between the economical HFO and
the expensive LSMDO. According to the assumptions in this project an investment in the
wet hybrid EGCS was slightly better, but it should only be used as a guideline. Currently it
would seem like the EGCS is a profitable investment due to the high fuel oil price
difference which is above 255 $ according to bunkerworld.com on 29th May 2013.
Therefore the conclusion to the main question is that this project has not been able to
conclude if the wet or the dry EGCS is the most sustainable in order to comply with the
future requirements/regulations.
Even though there is no clear conclusion, the main differences between the wet and dry
EGCS have been cleared in this project. The wet EGCS uses water to remove SOX and
consists of the open loop, closed loop and a combination of the two – the hybrid EGCS.
The open loop is a one way process discharging the used washwater overboard which
could be a problem if operating in sensitive areas. The closed loop and hybrid 21 EGCS
21
When operating in closed loop
74
Bachelor project
2013
consume aqueous sodium hydroxide (NaOH) also known as caustic soda to operate in a
closed loop system without any discharge overboard for a limited time. The dry EGCS
consumes calcium hydroxide granulate (Ca(OH)2) which has to be stored aboard.
Therefore the closed loop, the hybrid and the dry EGCS is the suitable choice if the vessel
is operating in sensitive areas due to the interdiction to discharge overboard. The Ca(OH)2
usage in the dry EGCS is considerably high according to weight and storage space
needed when compared to the consumables used in the wet EGCS. Therefore it only
seems possible to implement the dry EGCS on vessels with limited engine size and small
sea routes due to a realistic supply of Ca(OH)2.
The structure and weight of the dry EGCS is also significant compared to the wet EGCS
due to the dry EGCS significant superior weight which is placed in the upper part of the
vessel. Thus can the vertical centre of gravity be changed in a more negative way when
implementing the dry EGCS compared to the wet EGCS.
TIER III is supposed to implement tighter NOX limits inside ECA on 1th January 2016 on
new vessels or if the engines is reconstructed. Currently the North and Baltic Sea is only a
SOX ECA and therefore not applying to TIER III. There is a difference when comparing the
wet and dry EGCS about how they can be in a combination with NOX reduction
technologies in order to comply with TIER III limits. They can both use the developing
Exhaust Gas Recirculation system (EGR) to be compliant with TIER III. But if the wet
EGCS implement a standardised outlet to an EGR it could reduce the complexity of
implementing the EGR system. It is because the EGR system requires the recirculated
exhaust gas scrubbed and cooled. The Selective Catalytic Reduction system (SCR) needs
a high temperature (above 300oC) to be efficient. It is also a problem when operating on
HFO due to the catalyst element fouling caused by the high SO X levels in the exhaust gas.
In accordance to this the SCR should be placed after the EGCS. The wet EGCS is
decreasing the exhaust gas temperature significantly and additional heating is required for
the SCR to be efficient. The dry EGCS operates without any significant temperature loss
during scrubbing. Hence is the SCR system best suited for the dry scrubber.
The conclusion to all these differences is that each vessel should do their own assessment
about vessel type, NOX, operation hours, the economy and sailing routes before choosing
either the different types of wet EGCS or the dry EGCS.
75
Bachelor project
2013
11. Suggestions for further research
During this project other issues were encountered which could be studied further.

A further research on the economical part and where some different sailing routes is
suggested due to the annual operations hours, fuel oil price and time in and outside
ECA, price and availability of Ca(OH)2

Fuel availability in the future could also be another issue. Hence is there enough
capacity to deliver LSMDO from the refineries when the sulphur limit outside ECA is
tightened to 0.5 % in either 2020 or 2025 – or from 1 % to 0.1 % inside ECA in 2015
for that matter?

Problems with changing between the different fuel oil due to the fuels different
characteristics and the fuel equipment on the engines

SNOX FGD system used at power plants is deriving sulphuric acid from SOX
emissions and NOX is reduced to free nitrogen. Why is this technology not used in
the marine industry?

Is there an environmental issue with the wet EGCS overboard discharging water?
Afterword
This bachelor project is supposed to show how I can handle a project and widen my
knowledge by using the correct methods and analyse the obtained data. Although this was
the main purpose of this project it was also considered how some elements could be
implemented so some of the requests from Scandic Diesel Services was a part of it this
project. One e.g. is the: ”Compliance with the regulation” passage where it is explained
briefly how the EGCS could be in compliance with MARPOL Annex VI Regulation 4. To
reach the conclusion in this project it was not necessary to describe the details. Only
ensure that the wet and dry manufactures was in compliance with the regulation.
Another suggestion was that this project was written in English so it could be used
worldwide as a guideline for the costumers to Scandic Diesel Services. I agreed to write it
in English although I knew it would be a challenge for me compared to write this project in
my own language. Afterwards and in account of this I am happy that I did it because it
enhanced my English vocabulary and skills.
76
Bachelor project
2013
This project was supposed to include data and experience from a Clean Marine wet EGCS
installed on a vessel. I was also supposed to have visited the vessel and obtain empirical
data from the crew members and seen an EGCS installed on a vessel. This was one of the
main methods that should have been included in this project. It failed due to the limited
resources at Clean Marine and unfortunately I was cut of my main contact at Clean Marine
in the middle of this project. Therefore I went to other sources like persons working with
FGD on power plants, MAN Diesel and Haldor Topsøe. In account to this I have learned
that during a research project setbacks must be expected and that I should not rely on only
one source of information. I have also learned that it was difficult to obtain information from
the different sources when I am a student without backup from a larger company. I talked
to other students at my school and it seems like they have had another experience from
their point of view, due to backup from the larger companies where they did their
undergraduate trainee period.
I did my best to work professional with this project and I learned how realistic deadlines
should be established. Even though I worked hard with this project I found it difficult to
keep my own deadlines. At one point I came to a standstill where I could not manage to
figure out in what direction I should head for. Due to the frustration about this problem I
took a break from the project and studied how a student project should be done. I figured
out that I had two problems. At first I had not pointed out enough limitations in the
delimitation. Therefore I could not manage the situation. The other issue was that I did not
split the project up in smaller sections to focus on only one thing at the time. I got confused
when I read about one thing and then I went through my data to solve the question and
another issues showed up which I then tried to solve. I completed the delimitation and split
my project up in smaller sections. It helped me about the direction and that I should only
focus on one thing at the time.
I have learned that the initial planning is very important and that I should to be more
realistic when working on a project. In account to that I have learned about my own limits
and what I can accomplish.
77
Bachelor project
2013
12. References
Alejandro Hombravella, A. K. J. P. C. R., 2011. Study of Exhaust Gas Cleaning Systems.
Kiel: Fachhochschule Kiel, University of Applied Sciences.
Clean Marine, 2012. Process Description, Exhaust Gas Cleaning System (EGCS)
developed by Clean Marine A/S (Confidential). s.l.:Clean Marine A/S.
Couple system, n.d. The very new exhaust gas cleaning system.. Bardowick: Couple
System.
Couple, 2013. Couple-systems. [Online]
Available at: http://couple-systems.de/index.php/start.117.html
[Accessed May 2013].
DNV, 2009. Marpol 73/78 Annex VI - Regulations for the Prevention of Air Pollution from
Ships. Høvik: DNV (Det Norske Veritas).
ECG, 2011. Sulphur Content in Marine Fuels. Brussels: The Association of European
Vehicle Logistics.
EGCSA, 2012. A practical guide to exhaust gas cleaning systems for the maritime
industry, EGCSA Handbook 2012. 2 ed. London: Exhaust Gas Cleaning Systems
Association.
Egeberg, C.-E., 2009. Velkommen til Dieselhouse. Copenhagen: MAN Diesel A/S.
EU - Parliament, 2005. DIRECTIVE 2005/33/EC OF THE EUROPEAN PARLIAMENT
AND OF THE COUNCIL. Brüssels: Official Journal of the European Union.
78
Bachelor project
2013
EU - Parliament, 2012. Directive 2012/33/EU of the European Parliament and of the
Council of 21 November 2012 amending Council Directive 1999/32/EC as regards the
sulphur content of marine fuels. Luxembourg: Official Journal of the European Union.
IMO, 2013. International Maritime Organization. [Online]
Available at: www.imo.org
[Accessed 15 May 2013].
Jensen, A. E., 2013. Lector, Cand. Scient in physics and chemistry [Interview] (07 May
2013).
Joel Goodstein, 2013. Bachelorprojektet bliver til nyt måleinstrument. Maskinmesteren,
Volume 3, pp. 11-15.
Jürgens, R., 2012. Emission abatement technologies for HFO fuelled marine diesel
engines. Wiesbaden: Couple Systems.
Kevin J. Reynolds, PE, 2011. Exhaust Gas Cleaning Systems Selection Guide, Ellicott
City, MD: The Glosten Associates.
Kuiken, K., 2008. Diesel engines l. Onnen: Target Global Energy Training.
Kuiken, K., 2008. Diesel Engines ll. Onnen: Target Global Energy Training.
Larsen, S. K., 2012. Exhaust Gas Cleaning Systems. s.l.:Caterpillar Inc.
Likens, G. E., 2011. http://www.eoearth.org/. [Online]
Available at: http://www.eoearth.org/article/Acid_rain?topic=49506
[Accessed 24/05 - 2013 May 2013].
Lloyd's Register, 2012. Understanding exhaust gas treatment systems, Guidance for
shipowners and operators. London: Lloyd's Register.
79
Bachelor project
2013
Lodder, M., 2011. Dry Scrubber Technology. s.l.:MAN Diesel & Turbo SE.
Ministry of transport, 2009. Sulphur content in ships bunker fuelin 2015 - A study on the
impacts of the new IMO regulations on transportation costs. Helsinki: Ministry of transport
and communications Finland.
OECD, 2011. Environmental Impacts of International Shipping: The Role of Ports.
s.l.:OECD Publishing.
Ryan Albert and Shirley Fan, 2011. Exhaust Gas Scrubber Washwater Effluent,
Washington, DC 20460: United States Environmental Protection Agency, Office of
Wastewater Management.
80
Bachelor project
2013
13. Appendix
13.1 Appendix
RE: Ang. Spørgsmål til Alf og CO
Fra: Alf Helge Torkelsen (aht@cleanmarine.no)
Sendt: 11. april 2013 22:15:23
Til: sales@scandiserv.com (sales@scandiserv.com); Frode Helland-Evebø
(FHe@cleanmarine.no)
Cc: Ole Groulef Vestergaard (ov86@live.dk); Rasmus Vestergaard Jensen
(rasmus__vj@hotmail.com)
2 vedhæftede filer
Process description CM EGCS 20120318.pdf (556,9 KB) , P&ID with NaOH and BL
return.pdf (558,9 KB)
Hallo Canada
Jeg skal svare så godt jeg kan jeg Mikkel, så får du se om det kan være til noe hjelp.
1.
Kan der ikke monteres SCR anlæg på Wet Scrubber – kun Dry? - hvad med NOx?
Svar:
Dette er nok ikke helt tilfelle. Det er to ting som er viktig vedrørende SCR og scrubber. Det ene er
temperaturen etter en scrubber, og det andre er svovel i eksosgassen. «Katalysator stenene/
blokkene», har enda ikke vist seg å være særlig holdbare med svovel i eksosen. Her hevder riktig
nok noen av leverandør at dette er mulig med spesial «stener» for høy svovel, men det finnes ikke
tilstrekkelig dokumentasjon/ langtidstester på dette enda. Jeg snakket med MAN B&W
vedrørende dette for en uke siden, og de sier det samme, og kjører nå noen tester for å se om
holdbarheten er god nok. Hvis holdbarheten forbedres, så kan man kjøre en SCR foran scrubberen,
der eksos temperaturen fremdeles burde være høy nok for å få god nok virkning. Etter scrubberen
er jo svovel problemet løst, men her vil jo temperaturen være alt for lav til at en SCR kan fungere.
Uten at jeg vet nøyaktig temperatur fall etter en ”dry scrubber”, så vil jeg nok tro at den blir alt for
lav også her. En annen mulighet er jo og kjøre en «re-heat» av eksosen etter scrubber, slik at man
får høy nok temperatur til og kjøre det igjennom en katalysator etterpå. Vi har ikke levert noen
slike løsninger enda, men teknisk skulle ikke det være noe større problem. Er mer usikker på
energibehovet ved en slik løsning. Det er en annen løsning som nok vil være mye bedre, med
tanke på NOx problemet. Det vil være en kombinasjon av Scrubber og EGR, som vil kunne fjerne
en god del NOx. MAN B&W kjører denne linjen, og mener også at det vil være den beste løsningen
i dag. Det vil si at MAN ikke leverer scrubber, men utstyrer motorene sine med EGR. Den kan helt
greit kombineres med til dømes vår scrubber. Clean Marine har for øvrig også en patent på en
81
Bachelor project
2013
egen EGR løsning i kombinasjon med scrubberen. Her vil da en del av eksos gassen bli ført tilbake,
etter at den er reset igjennom scrubberen.
2.
Kan vi få et detaljeret beskrivelse af Clean Marines anlæg (teknisk)?
Svar:
Vedlagt finner du PDF fil med prosess beskrivelse og en illustrerende P&ID
3.
Hvad betyder det for driften af skibet / MA, at der monteres EGCS?
Svar:
Driften av skipet bliver ikke påvirket i noe spesiell grad. Systemet er selvjusterende og trenger
egentlig ikke noe annet enn å bli slått på eller av. Dette vil jo bli gjort inn og ut i ECA soner O.S.V.
Man må jo kanskje også planlegge litt vedrørende bunkring av NaOH, slik at man har nok av dette
til turen. Det vil jo være en ekstra kostnad her selvfølgelig. Ellers så kan det vel nevnes at skipets
«point of gravity» i liten grad blir endret, slik at man ikke må ta noen ekstra hensyn her. Det skal
generelt ikke være behov for noen ekstra maskinfolk for driften, og da heller ikke behov for noen
spesielle operatører. Vi vil gi en opplæring ved oppstart av systemet, slik at det blir vel kanskje slik
at maskinsjefen blinker ut en mann eller to som skal være ekstra kunnskap rik om dette. Det
daglige arbeide med utstyret, vil bare inngå i det vanlige generelle vedlikeholdet de har i
maskinen.
4.
Har der været uforudsete hændelser ved implementering af EGCS?
Svar:
Tja, det har det vel saktens, men i hvilken grad jeg kan si det var uforudsett vet jeg ikke I en
såpass omfattende implementering, er det jo litt av hvert som kan dukke opp, men det er jo også
noe man er forberedt på.
5.
Typiske fejl på anlægget?
Svar:
Her er det vel ingen av scrubber leverandørene som har nok driftstimer til å si noe eksakt om
dette. Vi har vel i hvert fall ikke noe liste på slikt enda.
6.
Forventet levetid på anlægget?
Svar:
Levetiden på anlegget generelt, er vel det samme som resten av skipets motor installasjon. Det vil
si at det jo er en hel masse av komponenter med ulik leve tid her. Vifter og viftemotorer har jo en
levetid, motor styrte ventiler, dyser og pumper en annen. Det finnes jo også en hel del sensorer og
data/ elektronikk, som ikke lever evig heller.
82
7.
Bachelor project
2013
Hvad skal der laves af service på anlægget?
Svar:
Her blir det jo levert service manual med i EGCS dokumentasjonen, men generelt så kan jeg vel
nevne at det er noen filter som inn i mellom skal skiftes på gassmåler utstyret. Det er også filter og
siler på vannsiden, som jo også må rengjøres fra tid til annen. Videre så er det jo en kalibrerings
prosedyre på analyse systemet, som kan være litt ulike etter leverandør av dette. Vi har ikke låst
oss til noen på dette, og jeg vet ikke nok om de ulike leverandørene sine krav til dette. Systemet
kan fjern kjøres og det kan gjøres ulike tester og kontroller fra vårt kontor, men det vil vel være
behov for en årlig service/ kontroll om bord på skipet. Service på alle de ulike komponentene blir
som nevnt beskrevet i egen service manual, og vil også kunne være litt ulik etter hvilke parameter
leverandørene har satt opp. Vi er ikke låst på noen spesielle leverandører her, slik at det kan være
noe
endringer
mellom
hver
installasjon.
Alf Helge Torkelsen
Senior Sales Engineer
Mobile: +47 913 52 432
E-mail: aht@cleanmarine.no
Switchboard: +47 21 04 33 11
www.cleanmarine.no
83
Bachelor project
From: Mikkel Elsborg - Scandic Diesel [mailto:mie@scandiserv.com]
Sent: 10. april 2013 15:06
To: Alf Helge Torkelsen
Cc: Ole Groulef Vestergaard; Rasmus Vestergaard Jensen
Subject: FW: Ang. Spørgsmål til Alf og CO
Hi Alf,
Kan du hjaelpe med svar 
Please respond to our general e-mail address sales@scandiserv.com,
Best regards
(Mr.) Mikkel Elsborg – President
Scandic Diesel Services Inc - It's smooth sailing from here
+1 514 566 1553 (Cell phone) | +1 514 228 1299 (Office – 24 hrs)
+1 514 221 3270 (Primary fax) | +1 514 256 8237 (Secondary fax)
mie@scandiserv.com | sales@scandiserv.com
Please visit our website www.scandicdiesel.com for latest news and product lines..
Ellers har jeg disse spørgsmål foruden Rasmus's til Alf:

Kan der ikke monteres SCR anlæg på Wet Scrubber – kun Dry? - hvad med NOx?

Kan vi få et detaljeret beskrivelse af Clean Marines anlæg (teknisk)?

Hvad betyder det for driften af skibet / MA, at der monteres EGCS?

Har der været uforudsete hændelser ved implementering af EGCS?

Typiske fejl på anlægget?

Forventet levetid på anlægget?

Hvad skal der laves af service på anlægget?
Vi ses til middag
84
2013
Bachelor project
2013
13.2 Appendix
RE: Ang. Hjælp til BA-Projekt. Ox s rubber
Fra: Viggo Rahbek Warming (vigwa@dongenergy.dk)
Sendt: 26. maj 2013 16:48:22
Til: 'Ole Groulef Vestergaard' (ov86@live.dk)
1 vedhæftet fil
3540_001.pdf (1151,5 KB)
Hej
Se svar herunder med rødt
Med venlig hilsen
Viggo Rahbek Warming
Driftsmester
Studstrupværket Driftsmestre
DONG Energy
Tlf. +45 99 55 66 31
From: Ole Groulef Vestergaard [mailto:ov86@live.dk]
Sent: Thursday, May 23, 2013 9:14 AM
To: Viggo Rahbek Warming
Subject: RE: Ang. Hjælp til BA-Projekt. SOx skrubber
Hej Viggo
Mange tak - vi havde en god session med Max.
Vi snakkede også om DeNOx anlæg, fordi på skibene har de problemer med, at der kommer
slagger fra svovl'en på elementerne i katalysatoren. Og det kan elementerne ikke holde til. Jeg tror
i tænker på ammoniumbisulfat,NH4HSO4. Det er et klistret stof som binder flyveasken, og det kan
ikke sodblæses bort.
En løsning kunne være at sætte katalysatoren efter scrubberen, som fjerner svovl'en, men det
giver for lav temperatur da scrubberen køler gassen. . Se vedhæftede fil vedrørende DeNOx kemi
Renser I også katalysatoren med sodblæsning?
Vi lyd sodblæser katalysatoren flere gange dagligt, derudover sodblæser vi med damp 1 gang / døgn.
Blæsninger fjerner dog kun støv (flyveaske).
85
Bachelor project
2013
Men for at gøre en lang historie kort så nævnte Max, at du måske vidste, hvor tit jeres elementer
skal skiftes i katalysatoren pga. at det har I gjort for nyligt? Og det må svovlindholdet vel også have
indflydelse på?
Normalt har vi 2 lag i katalysatoren, når effektiviteten falder installeres der et 3 lag efter ca 2 år.
Dette forlænger hele kattens levetid med min 1 år.
Fortsat god dag til dig.
Venligst
Ole og Rasmus
Aarhus Maskinmesterskole
OV86@live.dk
29865233
From: vigwa@dongenergy.dk
To: ov86@live.dk; rasmus__vj@hotmail.com
Subject: RE: Ang. Hjælp til BA-Projekt. SOx skrubber
Date: Fri, 17 May 2013 17:59:04 +0000
Hej
Se svar herunder med rødt. se vedhæftede vedr. afsv kemi, og hvordan vi driver vore
anlæg. http://www.techmedia.dk/default.asp?Action=Details&Item=680
Filen TASP anlæg er et intern kursus dokument
Mine svar er baseret på et tøranlæg hvor restproduktet kaldes TASP.
86
Bachelor project
2013
I vender bare tilbage hvis der er flere spørgsmål
Med venlig hilsen
Viggo Rahbek Warming
Driftsmester
Studstrupværket Driftsmestre
DONG Energy
Tlf. +45 99 55 66 31
Sent: Friday, May 17, 2013 12:38 PM
To: Viggo Rahbek Warming
Cc: Rasmus Vestergaard Jensen; Anders Warming
Subject: Ang. Hjælp til BA-Projekt. SOx skrubber
Hej Viggo
Vi er to maskinmesterstuderende som går i klasse med Anders.
Han sagde at du gerne ville hjælpe med et par spørgsmål, hvilket vi er meget taknemmelige for. Vi
skriver om afsvovlingsanlæg på skibe
og vil gerne trække paralleller til landbaserede enheder.
Vi tænker ikke så meget på hvordan det fungerer teknisk.
Vi tænker:

Kalksten til opblanding af vandet. Hvad består det helt præcist af, er der kvalitetskrav og er det
billigt og nemt at få fat på. Det ”gips produkt” som udvindes, hvordan er distributionen af det?
Vi anvender brændt kalk der modtages fra Faxe eller Gotland
Går det til cementvirksomheder eller? SSV ( Studstrupværket) restprodukt anvendespå Esbjerg
værket og om dannes til gips. Se vedhæftede vedr. kemi

Hvordan ser driften af systemet ud - typiske fejl osv. Mekaniske, elektriske, kemiske
fejl? Overvejende fejl / udfordring er at opnå en tilfredsstillende økonomi i driften, Vi skal afsvovle
røgengassen til ca 10 ppm SO2 og dette kan somme tider være problematisk idet vi også har
kvalitets krav til TASP da den skal anvendes i Esbjerg, se vedhæftede.
87

Bachelor project
2013
Vedligehold og eftersyn af systemet – skal selve skrubberen renses engang i mellem og have
udskiftet dyser med mere, er der korrosions problemer, eller er der andre ting, som vi ikke har
overvejet (se også nedenstående)?
Vi anvender time baseret vedligehold på kritiske komponenter, derved undgår vi haverier af større
omfang.
Vedrørende vore opblandings tanke renses de 1 gang årligt.
Eks. kan vi læse os frem til, at der på nogle anlæg har været fejl med for lav pH værdi, her står:”
Dog har man på flere anlæg oplevet et fald i pH, som ikke kunne imødegås ved øget
kalkstensdosering. Årsagen er at aluminium (Al) hidrørende fra flyveaske og fluor (F) danner en
tungt opløselig forbindelse, der inaktivere opløsningen af kalkstenen”Ikke relevant for tør
anlæg

Spildevand – her tænker vi på pH værdien. Udledes det direkte i havnen og hvad med miljøet ang.
det?
Ellers også overordnet konklusion på systemet, hvis du har noget uddybende at fortælle om det.
Har du hørt om et bedre system eks. SNOx anlæg?
Vi har seperate anlæg, et DeNOx anlæg ( såkaldt high dust anlæg) og et afsv. anlæg, SNOx anlæg kender jeg nok til.
Venligst
Ole og Rasmus
Aarhus Maskinmesterskole
OV86@live.dk
29865233
88
Bachelor project
2013
13.3 Appendix
Fw Mail til Mi
el udt
h
lp til - ro e t
Fra: Anders Rooma Nielsen (arni@topsoe.dk) på vegne af dnxsupport@topsoe.dk
Sendt: 27. maj 2013 13:59:08
Til: ov86@live.dk
Cc: htj@topsoe.dk; hajh@topsoe.dk
1 vedhæftet fil
NOx reduction system for diesel engines_WIP May 2011.pdf (2,4 MB)
Hej Ole,
Jeg vil forsøge at svare på dine spørgsmål her:
1. Inden for NOx-reduktion med SCR-teknologi har vi i høj grad mulighed for at skræddersy katalysatoren så
den passer til forholdene. Er brændslet fx. heavy fuel oil med højt svovlindhold vil vi typisk bruge en
katalysator med lavt vanadium-indhold, hvilket giver en lavere SO2-oxidation.
Der er dog også forhold, som vi har svært ved at gøre noget ved: Højt svovlindhold og lave temperaturer
(typisk under 300°C) er en skidt kombination. Der vil være risiko for ammonium-bisulfat (ABS) udfældning i
katalysatoren, hvilket reducerer aktiviteten. Det eneste vi kan gøre i dette tilfælde er, at regenerere
katalysatoren med jævne mellemrum. Regenereringen består i, at opvarme katalysatoren til fx 350°C, så
ABS vil fordampe fra katalysatoren. Denne regenerering kan gøres, hvis der er installeret en brænder til at
varme røggassen op med.
2. Kat-elementerne kan selvfølgelig udskiftes, men det koster jo penge. Sodblæsning bruges ofte på skibe til
at holde elementerne rene (i form af trykluft-dyser installeret ved hvert katalysatorlag). Men sodblæsning vil
ikke fjerne alt ABS, som godt kan dannes i katalysatorens små porer, og derfor kun kan fjernes ved
opvarmning (=fordampning).
3. Jeg er ikke helt med på hvad du mener med slagge-dannelse på elementerne...? En brænder kan godt
bruges til at hæve temperaturen. Dog kan elementerne ikke tåle højere kontinuerte temperaturer end 540°C.
Jeg håber, at dette gjorde dig lidt klogere. Ellers er du velkommen til at kontakte mig igen for mere
information.
Mvh
Anders Rooma Nielsen
Catalyst & Process Specialist, PhD, Chem. Eng. | DeNOx and VOC Control Technologies, Environmental Business Unit
Haldor Topsøe A/S
Catalyzing your business
Nymøllevej 55, DK-2800 Kgs. Lyngby
Phone (direct): +45 2275 4627
Switchboard: +45 4527 2000
Read more at www.topsoe.com
Created on 23-05-2013 13:23:55 by hes
89
Bachelor project
2013
To:
"denox@topsoe.dk" <denox@topsoe.dk>,
cc:
bcc:
Subject:
FW: Mail til Mikkel Budtz (hjælp til B-Projekt)
Hej Haldor Topsøe
Har fået automatisk svar tilbage pga. Henrik ikke er tilbage før 31 maj.
Kan I evt. svare tilbage på nedenstående inden for rimelig tid, da jeg skal aflevere projektet d. 4
Juni.
Mvh
Praktikant: Scandic Diesel Services
Studerende – Aarhus Maskinmesterskole
Ov86@live.dk
From: ov86@live.dk
To: htj@topsoe.dk
Subject: RE: Mail til Mikkel Budtz (hjælp til B-Projekt)
Date: Thu, 23 May 2013 11:27:07 +0200
Hej Henrik
Du sendte mig nedenstående i april. Og jeg er meget taknemmelig.
Jeg har undersøgt NOx reduktion yderligere, og der er et par spørgsmål, som presser sig på.
Jeg tænker:



Er der udviklet katalysatorer, som kan klare det høje svovlindhold i heavy fuel? Jf. s. 20 i
første spalte i vedhæftede. Har du evt. mere materiale omkring dette?
Ellers er der ikke mulighed for at udvikle udskiftelige elementer og sodblæsning ligesom på
kraftværker så problemet med for det høje svovlindhold kan imødekommes?
Har også læst i det tilsendte at højere temperaturer i katalysatoren, kan hjælpe på
dannelsen af slagger på elementerne - er det en brugbar løsning ved evt. at koble en
"burner" på?
Venligst
Ov86@live.dk
90
Bachelor project
2013
To: ov86@live.dk
CC: mie@scandiserv.com; rasmus__vj@hotmail.com; jens.peterhansen@alfalaval.com
Subject: Re: FW: Mail til Mikkel Budtz (hjælp til B-Projekt)
From: htj@topsoe.dk
Date: Fri, 19 Apr 2013 11:06:41 +0200
Hej Ole,
Skrubbere er spændende men vi er SCR eksperter her her i huset. I dag udvikler og sælger vi katalysator og
proces know how (tidligere hele anlæg)
SCR sidder før Scrubber grundet temperaturen. Svovl og SCR Scrubber kombination er måske en
udfordring men der er ringe erfaring på området og mange mulige løsninger hvis det ikke bare kører.
Jeg talte men en branche kollega som er førende inden for marine skrubbere, Jens Peter fra Alfa Laval, cc
her. Han har ikke tid til aktive at støtte dig med dit projekt men henviser til Alfa Lavals hjemmeside.
Jeg tror også du kan være heldig at han kan sende dig lidt yderligere materiale hvis du sender han en venlig
maill. Start med at sætte dig godt ind i tingene så du ved hvad du skal spørge om.
Jeg vedhæfter lidt info om SCR du er velkommen til at bruge hvis du husker at referere til kilden.
God arbejdslyst
Mvh
Henrik
Henrik Trolle Jacobsen
B. Sc. Mech. Eng. Area Sales Manager | Catalyst end Technology | Environmental
Haldor Topsøe A/S
Catalysing your business
Nymøllevej 55, DK-2800 Kgs. Lyngby
Mobile: +45 2265 7547
Read more at www.topsoe.com
91
<ov86@live.dk> 18/04/2013 20:17
Bachelor project
To
cc
2013
"htj@topsoe.dk" <htj@topsoe.dk>,
Mikkel Elsborg Scandic Diesel Service <mie@scandiserv.com>, Rasmus Vestergaard
Jensen <rasmus__vj@hotmail.com>,
Subject FW: Mail til Mikkel Budtz (hjælp til B-Projekt)
Hej Henrik
Jeg er maskinmesterstuderende og kontakter dig jf. nedenstående korrespondance.
Jeg har været i kontakt med Mikkel Budtz Nielsen gennem Mikkel Elsborg, som er CEO ved det
firma, hvor jeg er i praktik.
Kan du hjælpe i den forbindelse - se den første mail.
Venligst
From: Mikkel Budtz Nielsen [mailto:mbn@topsoe.co.za]
Sent: April-18-13 1:50 PM
To: mie@scandiserv.com
Subject: Re: Mail til Mikkel Budtz
Hej Mikkel
Jeg tror der ligger noget på haldortopsoe.com.
Din mor har været i kontakt med Henrik Trolle fra HT A/S som er manden i københavn som har
med skibs SCR (og kraftværker) at gøre.
Mvh Mikkel
Sent from my iPhone
92
Bachelor project
2013
Sent: April-18-13 12:09 PM
To: Mikkel Elsborg Scandic Diesel Service
Subject: Mail til Mikkel Budtz
Hej Mikkel
Jeg er i praktik ved Mikkel Elsborg i Canada, som maskinmester og er i den forbindelse i gang med
at skrive bachelorprojekt vedr. Exhaust Gas Cleaning System (Scrubbers) på skibe. Dette er dog et
relativt nyt indenfor den maritime sektor, og derfor leder jeg efter materiale/info omkring emnet
fra kraftværker. Her tænker jeg på, hvordan systemet fungerer rent teknisk, hvilke udfordringer
som opstår i forbindelse med scrubbers eks. hvor meget spilprodukt som opstår ved brug af
scrubbers. Her tænker jeg både på wet og dry scrubbers. Energiforbrug ved brugen af scrubbers
ect.
Kan også forstå at der ved brug af SCR er problemer med svovlindholdet i udstødningsgassen, og
ved brug af diverse scrubbers, som fjerner svovlen – giver det problemer med temperaturen ind i
SCR da scrubber’en sænker temperaturen under driftstemperatur i SCR?
Drift og service af scrubber systemer?
Kan du hjælpe?
Venligst
Ov86@live.dk
Haldor Topsøe A/S: CVR: 41853816 This e-mail message (including attachments, if any) is confidential and may be privileged. It is intended
only for the addressee.
Any unauthorised distribution or disclosure is prohibited. Disclosure to anyone other than the intended recipient does not constitute waiver of
privilege.
If you have received this e-mail in error, please notify the sender by e-mail and delete it and any attachments from your computer system and
records.
HALDOR TOPSOE (www.topsoe.com)
93
Bachelor project
2013
13.4 Appendix
RE: Hjælp til Bachelorprojekt
Fra: Jesper Arvidsson (Jesper.Arvidsson@man.eu)
Sendt: 28. maj 2013 08:03:41
Til: Ole Groulef Vestergaard (ov86@live.dk)
Hej Ole
Vores holdning til Tier II problematikken er, at vi gerne vil beholde heavy fuel og dermed
fleksibiliteten for vores kunder. Vi har valgt at forholde os sådan, at det som direkte kan påvirkes
gennem forbrændingsprocessen eller umiddelbart på motoren er i vores ”scope” – dvs primært
NOx reduktion. Al røggasbehandling og alt hvad der i øvrigt foregår ude i systemet (Scrubbere,
kedler o.lign.) vil vi evaluere og samle erfaring omkring, men ikke selv udvikle.
Vores NOx-tilgang består af to sideordnede teknologier – EGR og SCR. Hvor vi som du ved har
udviklet et færdigt EGR-system som vi allerede nu leverer, er der lidt længere udsigter med
SCR. SCR er vanskeligt – især på en to-takt motor – fordi det kræver ret høje udstødstemperaturer
og fordi SCR-cellerne ikke ret godt kan lidt svovl i brændolien (som du også selv er inde på). Vi
forsker og udvikler fortsat på dette sammen med ledende leverandører.
EGR systemet kan uden tvivl udformes på mange måder. Vi har valgt at montere det direkte på
motoren således at vi ikke er ”afhængige” af feks en scrubber for at systemet skal kunne virke. Det
skal dog siges at vi løbende evaluerer hvilke synergier der kan være at finde i at kombinere
forskellige systemer og teknologier og jeg vil da ikke udelukke at vi laver et system kombineret
med en SOx scrubber.
Vi har ikke haft nævneværdige problemer med slagger osv. De største problemer vi har haft med
EGR har været udfældning af salte samt for ringe (ikke korrosionsresistente) materialer i vores
første udgaver.
Der har været lidt lækager af udstødsgas omkring ventiler osv men dette har vist sig at stamme fra
fejl i samlingen af pakdåserne på ventilerne – de var simpelthen ikke spændt ordentligt sammen.
Vores sidste udgave af EGR er lige nu idriftsat og sejler på et Maersk skib med rigtig gode
resultater.
Mvh
Jesper
94
Bachelor project
2013
Sent: 23. maj 2013 18:08
To: Jesper Arvidsson
Subject: RE: Hjælp til Bachelorprojekt
Hej Jesper
Tak for det de meget fine svar - jeg skriver nogle fine referencer ind i mit projekt.
Ang. flere spørgsmål er jeg faktisk nysgerrig ang. jeres tilgang til at kunne overholde NOx jf. TIER III
i forhold til at have både SOx (scrubber) og NOx reducering på.
Kan her forstå at water emulsification ikke er tilstrækkelig, og derfor skal der enten installeres SCR
eller EGR.
Jeg tænker eks.



Jeg har læst lidt på jeres EGR system, hvor der er scrubber til at rense det recirkulerende
gas (undgå corrosion osv.), men kunne det ikke ligeså godt tages fra en evt. installeret
scrubber, så det ikke behøver at være en integreret del af EGR systemet. Eks. kunne et
udtag på standardiserede scrubberer ikke afhjælpe kompleksiteten af EGR systemet?
Jeg har i min tid som automekaniker oplevet mange problemer med EGR-systemer. Er det
ikke det samme, man oplever ved at recirkulere udst-gassen på skibe? Eks. slagger,
problemer med ventiler osv.
Ang. SCR - se evt. nedenstående link. Er det ikke et problem med SOx slagger at placere
SCR før en evt. scrubber, hvis man opererer på HFO? Jeg ved, at på kraftværker har de
installeret sodblæsning, som de bruger ca. en gang i døgnet og mulighed for at udskifte
elementerne i katalysatoren - er det ikke en mulighed indenfor dieselmotorer også?
http://www.mandieselturbo.com/1014557/Press/Press-Releases/Trade-Press-Releases/MarinePower/Medium-Speed/MAN-Diesel-PrimeServ-Retrofits-First-SCR-System.html
På forhånd stor tak!
Kind regards/yours sincerely
Marine Engineering student at Aarhus School of Marine and Technical Engineering (Aarhus
Maskinmesterskole)
Denmark
OV86@live.dk
+45 29865233
95
Bachelor project
2013
From: Jesper.Arvidsson@man.eu
To: ov86@live.dk
CC: Jesper.Gram@man.eu
Subject: RE: Hjælp til Bachelorprojekt
Date: Thu, 23 May 2013 07:31:51 +0000
Hej
Jeg har fået din forespørgsel fra min kollega og skal hermed forsøge at besvare nogle af dine
spørgsmål. Du er velkommen til at vende tilbage med yderligere spørgsmål.
Dry scrubbers som system kan anvendes både på to og firetaktsmotorer. Temperaturerne på
udstødsgassen både på to og firetaktsmotorer ligger vel indenfor dry scrubberens operationelle
virkeområde.
Systemet har imidlertid den ulempe, at der anvendes ret store mængder CaOH som skal kunne
bunkres ombord.
Da CaOH’en ikke opbruges som produkt men i stedet virker som absorber, er man desuden også
nødt til at kunne opbevare det brugte media indtil det er muligt at debunkre.
Man skal altså groft sagt have plads til 2 gange den forventede forbrugsmængde ombord. På en
større motor (typisk en to-takt hovedmotor) skal der qua den større effekt/røggasmængde bruges
ret store mængder og det stiller store krav til pladsen ombord.
Der er desuden logistikken ved bunkring/debunkring. Hvis et skib med en større motoreffekt skal
bunkre/debunkre CaOH nok til et rimeligt antal driftstimer før næste bunkring, vil det kræve
adskillige lastbil-læs med media.
For at sætte lidt tal på vil der (ifølge Couple) skulle anvendes ca 16 kg/h/MW ved 2.7% S fuel og et
fuelforbrug på 200g/kWh. Til en større motor (feks 40 MW) svarer dette altså til et forbrug på ca
15,3 ton/døgn.
Skal der bunkres nok til drift mellem normale bunkerstop skal der altså bunkres 3-400 tons media
ad gangen ( - og debunkres lige så meget.)
Desuden er det langt fra et almindeligt lagerprodukt men skal bestilles særskilt til leverance i den
valgte bunkerhavn.
Der ud over er et dry scrubber anlæg ret omfangsrigt hvilket taler imod retrofit-løsninger for
større skibe. Couple angiver selv at et anlæg til en 20 MW motor vil fylde 63 m2 og dertil 13
meter i højden med en anslået driftsklar anlægsvægt på 294 ton.
Vi ser derfor anvendelsen ombord i WW trade skibe som begrænset men absolut som en mulighed
på ruter hvor man har begrænset motorstørrelse og få faste havne uden lange sø-passager. Det
96
Bachelor project
2013
kunne være færger i fast fart mellem to havne eller andre shuttle-lignende ruter hvor der kan
opbygges et fast supplysystem for medialeverancer.
For at prøve at svare på dine andre spørgsmål venligst se nedenfor;

Combination of Dry Scrubber and SCR would probably be possible in most cases. The dry scrubber
can operate at lower temperatures than required by the SCR –unit which means, that it is the SCR
that determines the operational profile – not the Dry Scrubber. The heat loss in the Dry Scrubber
is minimal (according to Couple), meaning that the inlet exhaust gas temperature will determine
the use of SCR. In some cases it has proven difficult to maintain sufficiently high exhaust gas
temperatures for proper SCR use – even without a dry scrubber, and alternate methods for
heating the exhaust gas before system entry must be devised.

As far as we know it is also possible to get the limestone granulate in Canada. The limestone
granulate is a well known industrial product, however whether it can be readily delivered in the
proper grain size for use in dry scrubber systems is not entirely clear.

The system is running mostly in automatic mode. Normal system knowledge as with all other
systems on board will be sufficient for crew.

Only one system has been delivered for a ship so far. Picture of the hopper on board M/V Timbus
(3,6MW engine) are supplied below. One more plant is reportedly ordered for a new building at
Flensburg FSG Yard, Germany.

System is basically consisting of a hopper, air fans and screw conveyors. Regular maintenance on
conveyors and electric motors is required.

We do not have detail drawings/photos – must be obtained from Couple Systems.

Process description below

Budgetary quote must be obtained from Couple Systems.
Vedlagt et dokument med lidt billeder.
Mvh
Jesper Arvidsson
Low Speed Engineering / Operation Dept.
MAN Diesel & Turbo
97
Bachelor project
Teglholmsgade 41,
2450 Copenhagen SV,
Denmark
From: Jesper Gram
Sent: 21. maj 2013 09:30
To: Jesper Arvidsson
Subject: FW: Hjælp til Bachelorprojekt
Med venlig hilsen/Best regards
Jesper Gram
Manager LEO8 - Emission Technology
MAN Diesel & Turbo,
filial af MAN Diesel & Turbo SE, Tyskland
Marine Low-Speed/Engineering/Operation department
Teglholmsgade 41, DK-2450 Copenhagen SV
( Phone (Direct):
+45 33 85 29 36
( Phone (Mobile):
+45 40 29 03 16
* E-mail (Office):
jesper.gram@man.eu
www.mandieselturbo.com
98
2013
Bachelor project
2013
Sent: 21. maj 2013 09:25
To: Jesper Gram
Subject: Hjælp til Bachelorprojekt
Hej Jesper
Her er de uddybende spørgsmål - den samme mail som jeg har sendt til Couple-systems, og hvis det
primært er i forbindelse med 4-takts motorer, som du nævnte, er det så grundet den varme, som er
nødvendig for at systemet fungerer, eller er der andre årsager?
I am a Danish Marine Engineering student who is writing about the differences between wet and dry
scrubbers in the shipping industry in my final thesis.
I am right now in favor for the dry system due to the ability of handling NOx emission by combining it
with the SCR. I am in lack of information and want to know if you can provide the needed information
for my project which is due 4th of June.
Questions on my mind:

Is it always possibly to combine the dry scrubber with SCR without additional heating? Any EGR
system in combination with DRY scrubber?

Is it only possible to get limestone in Europe as shown in the attached presentation?

What additional crew training is needed in regard of operation of the system?

Can you you provide a operation screenshot from a dry scrubber system on board a ship?

What maintenance is needed in this system?

Do you have a good picture of the cascade channels in the scrubber since I'm having problems
understanding how it functions?

If you can provide me with a process discription of the dry system?
And is it possible to get an overall budgetary quote/operation costs on these specification for the
financial aspects:

Main engine: 1 off MAN B&W 7S70ME-C

Power: 1 x 21,770 kW at 100%
99
Bachelor project

Auxiliary engines: 3 off MAN B&W 6L23/30H

Power: 3 x 780 kW at 100%

Boilers: 2 off OVS
2013
Any help provided will be well appreciated and my project can be confidential if you prefer that.
Kind regards/yours sincerely
Marine Engineering student at Aarhus School of Marine and Technical Engineering (Aarhus
Maskinmesterskole)
Denmark
OV86@live.dk
From: Jesper.Gram@man.eu
To: ov86@live.dk
Subject: hilsen
Date: Tue, 21 May 2013 07:14:13 +0000
Med venlig hilsen/Best regards
Jesper Gram
Manager LEO8 - Emission Technology
MAN Diesel & Turbo,
filial af MAN Diesel & Turbo SE, Tyskland
Marine Low-Speed/Engineering/Operation department
Teglholmsgade 41, DK-2450 Copenhagen SV
www.mandieselturbo.com
100
Bachelor project
13.5 Appendix
Data from confidential manufacturer.
used in the: ”Payback period regarding EGCS”
101
2013

Comparing Wet and Dry Exhaust Gas Cleaning Systems

Transcription

Similar documents

Exhaust Type: SINGLE HYPERLOW SYSTEM - Motokufry-AM

Accudraft 3000 Prep Station

Sexy hausfrau

Page 8

PART NO. 15312 2014 FIAT 500L 1.4L TURBO

Ole Fuego Functions 2016

West Calcasieu Association of Commerce

brochure

COMPUTER SCIENCE