2. ABSTRACT
Ship’s SOX emissions forms 60% of total SOX
Emissions.
We are polluting our environment by our
choice of fuel.
Emission control in the angle of MARPOL
and the technologies for reduction are taken
into account.
3. POLLUTANTS
Air pollutants can also be of primary or secondary
nature.
Primary is emitted directly to atmosphere.
Secondary is formed by reactions between primary
pollutants.
The major pollutants are
1. Oxides of nitrogen
2. Oxides of sulphur
3. Particulate matter
5. HAZARDS
Corrosion
Climate change
Photochemical smog
SO2 irritates the eyes, nose and lungs
SO2 causes acid rain
NO2 causes pulmonary edema
6. MARPOL LEGISLATION
Annex VI- Regulations for the prevention of
air pollution from ships
Came to force on 19th May 2005
For every ship with 400 gross tonnage and
above and for fixed and floating drilling rig
Certificate- “International air pollution
prevention certificate”
Validity- period not exceeding five years
7. MAJOR REGULATIONS
There are 19 Regulations but the following
Regulations impact Vessel operation :
Regulation 12 – Ozone Depleting Substances
Regulation 13 – NOx emissions
Regulation 14 – Sulphur Oxide emissions
Regulation 15 – VOC emissions
Regulation 16 – Shipboard Incinerators
Regulation 18 – Fuel Oil Quality control
8. Emission standards are referred to a Tier I,
II,III
Tier I came into force on 19th May 2005.
The revised Annex VI enters into force on 1st
July 2010.
Tier II,III are more stringent than Tier I .
Tier II standards are expected to be met by
combustion process optimization.
Tier III standards are expected to require
dedicated NOx emission control technologies.
9. REGULATION 13
Deals with control of NOX emissions.
All engines with power more than 130KW and
built on or after 1/1/2000
Doesn’t apply to engines used in emergency.
Emissions must be limited to,
17.0 g/kWh when n <130 rpm;
45.0 x n-0.2 g/kWh when n is 130 or more but
less than 2000 rpm;
9.8 g/kWh when n is 2000 rpm or more
10.
11.
12. SOX CONTROL
Sulphur content of fuel shall not exceed 4.5%.
SOX emission ECA include Baltic and North sea
area.
Sulphur content shall not exceed 1.5% in ECA.
Total emission must be less than 6 g SOX/kWh
in ECA
13.
14.
15. FUEL OIL QUALITY
Fuel oil shall be free from inorganic acid.
Bunker delivery note must be maintained.
Bunker delivery note must kept for 3 years.
Fuel oil sulphur content must never exceed
4.5%.
Parties of 1997 protocol must maintain a
register of local suppliers of fuel oil.
16. EMISSION MEASUREMENT
For Attaining Interim Certificate of
Compliance.
Engines combined into engine groups by
manufacturer
Engine from this group selected for emission
testing
17. EXHAUST GAS MONITORING
TECHNIQUES
Exhaust Gas
Monitoring
Equipments
EExxttrraaccttiivvee
SSyysstteemmss NNoonn--EExxttrraaccttiivvee
SSyysstteemmss
UUVV AAnnaallyysseerrss Chemi-luminescence
IInnffrraarreedd
AAnnaallyysseerrss
UUllttrraa--VViioolleett
AAnnaallyysseerrss
18. Extractive Systems
Permanently installed
Requires additional equipment to process the
exhaust gas sample.
Advantages
Able to be remotely located in a controlled environment
Easier to operate, calibrate and maintain.
Can be set up to monitor exhaust gas emissions from more
than one engine.
Disadvantage
High Cost
19. NON-EXTRACTIVE SYSTEMS
Predominately use infrared or ultra-violet
techniques.
Measure the exhaust gas emissions without
extracting the exhaust gas from the uptake
system.
Advantages
More portable
Provides more rapid responses.
Disadvantages
Difficult to calibrate.
20. CHEMILUMINESCENCE
HCD (Heated Chemiluminescence Detector).
Accepted standard for laboratory and test cell
measurement of NOx.
Was the only available NOx detector available
during the development of the IMO Technical
code.
Needs to have a continuous supply of clean
dry air else damage to the analyser
components will result.
NO determination with detection limits down
to 1 ppb.
21. ULTRA-VIOLET ANALYSERS
Particularly useful for measuring SO2 .
Used in extractive and non-extractive systems.
Not suitable for the measurement of NOx.
22. REDUCING SOX EMISSIONS
2 Possibilities :-
Burning fuels with lower sulphur content
Treating the engine exhaust gases
At Present limits on sulphur content of marine
fuel
Globally – 4.5%
SECA – 1% from 1st july,2010
SOX emission control areas (SECA)
North Sea, English Channel and the Baltic Sea.
23.
24. TECHNIQUES FOR
REDUCING SOX EMISSIONS
3 possibilities to reduce SO2 emissions from
combustion processes:
1) REMOVAL OF SULPHUR BEFORE COMBUSTION
2) REMOVAL OF SULPHUR DURING COMBUSTION
3) REMOVAL OF SOX AFTER COMBUSTION ( I.E.
FLUE GAS DESULPHURISATION )
25. REMOVAL OF SULPHUR
BEFORE COMBUSTION
Process used : Hydrotreating or Hydrodesulphurisation
Treatment of the oil with hydrogen gas obtained e.g. during
catalytic reforming.
Sulphur compounds are reduced by conversion to hydrogen
sulphide (H2S) in the presence of a catalyst.
H2S washed from the product gas stream by an amine wash
H2S is recovered in highly concentrated form
Converted to elemental sulphur via the Claus-Process
Feedstock is mixed with hydrogen-rich make-up and recycled
gas and reacted at temperatures of 300 - 380 °C.
26. Removal of sulphur from heavier oils such as marine fuel oil
often requires pressures of up to 200 bar.
Catalysts employed : cobalt, molybdenum or nickel finely
distributed on alumina extrudates.
27. CLAUS PROCESS
Most significant Gas desulphurizing process
Recovers elemental sulphur from gaseous
hydrogen sulphide
The overall main reaction equation is:
2 H2S + O2 → S2 + 2 H2O
28.
29. REMOVAL OF SULPHUR
DURING COMBUSTION
Experimental Stage
The combustible compound is mixed with an
admixture of water soluble and water insoluble
sulphur sorbent.
Such admixtures, remarkably, produces a
reduction in the SOX level far greater than
would be expected based on the activity of
each sorbent alone.
31. LIMESTONE/GYPSUM
SYSTEM
Most widely used process
Principle
Suspension of crushed limestone in water is
sprayed into the flue gases.
SO2 reacts with calcium ions to form calcium
sulphite slurry
Aeration of the slurry with compressed air
oxidizes calcium sulphite to calcium sulphate
After removal of the water, the calcium
sulphate can be disposed off
32.
33. Advantage :
SO2 reduction around 90 %
Disadvantages :
limestone has to be stored onboard
large quantities of gypsum waste is produced
34. SPRAY DRY SYSTEM
A slurry of slaked lime is used as an alkaline
sorbent
The slurry is injected into the flue gases in a
fine spray.
The flue gases are simultaneously cooled by
the evaporation of water
The SO2 present reacts with the drying sorbent
to form a solid reaction product, with no
wastewater.
35. WELLMAN-LORD PROCESS
Hot flue gases are passed through a pre-scrubber
Ash, hydrogen chloride, hydrogen fluoride and SO3 are
removed.
the gases are then cooled and fed into an absorption tower
SO2 reacts with a saturated sodium sulphite solution to form
sodium bisulphite.
The sodium bisulphate is regenerated after a drying step to
sodium sulphite again.
The released and clean SO2 - may then be liquefied or
converted to elemental sulphur or sulphuric acid.
The sorbent is regenerated during the combustion process and
is continuously recycled, but the products (sulphur
compounds) have to be stored.
36. TTHHEE SSEEAAWWAATTEERR SCRUBBER
Krystallon Sea-Water Scrubber
Removes 90-95 % of SO2
In addition removes 80 % of the particulates
and 10-20% of hydrocarbons.
Advantages
♦ no limestone has to be stored on board,
♦ no waste (gypsum) is produced, which has to
be deposited on land,
♦ the seawater already contains substantial
amounts of sulphate and nitrate
♦reduction of engine noise and a reduction of
the diesel smell..
37. FFeeaattuurreess
Uses Cyclone Technology
The system needs only a little extra space
Aeration of the effluent is necessary
high degree of recirculation
38. WWoorrkkiinngg
Water in contact with hot exhaust gas
Exhaust gas is channelled through a concentric
duct into a shallow water tank.
Mixing baffles break up large gas flow into
smaller bubbles
SOx in exhaust gas is dissolves in seawater
Larger particles (greater than 2.5 micron)
captured in the water.
Fine particles (smaller than 2.5 micron) may
pass through without capture.
39. Pumped through a set of large cyclones
Designed to separate some of the heavy
particles, as well as light particles in a two-stage
system.
Fed to a settling tank for collection of soot and
oil.
Runs with no ongoing maintenance
Cleaned recirculated water is maintained at
extremely low concentrations of hydrocarbons,
making it safe for discharge to sea.
40.
41. OPERATIONAL CONCERNS
AROUND THE CHANGE TO
LOW SULPHUR FUELS
REDUCED FUEL VISCOSITY
FUEL ACIDITY
IGNITION AND COMBUSTION QUALITY
FUEL LUBRICITY
42. REDUCED FUEL VISCOSITY
MGO and MDO fuels have a lower inherent
viscosity than heavy fuel oil which can :
Effect Diesel Engines
Effect Steam Boilers
43. Effect On Diesel Engines
Changes in fuel atomisation
Adversely affects power output and engine
starting performance.
Solution Recommended : Use fuel coolers to
control fuel viscosity
44. Effect On Steam Boilers
Affects fuel flow setting (for a given pressure)
at the burners
Can lead to “Over Firing”
Increased risk of flame failures and flame
impingement on boiler tube plates.
Solution Recommended :
Change the nozzle
Or the air/fuel ratio settings
45. FFUUEELL AACCIIDDIITTYY
Does not present a problem for steam boilers
But has a significant effect on diesel engines
Engine lube oils are formulated with alkaline
additives to neutralise the acidic, sulphur, by-products
of combustion.
IF amount of sulphur in the fuel is reduced, THE
amount of alkaline additives should be reduced.
Too much alkalinity causes build-up of deposits that
will affect the lubricating film
Solution Recommended : Oil with a lower Base
Number (BN).
47. Effect On Diesel Engines
Poor combustion and ignition may lead to
increased fouling of the engine
Fouling is so excessive that moving parts such
as exhaust valves are inhibited by the soot,
leading to broken/bent valves
Excessive fouling of the scavenge air receiver
combined with late ignition or prolonged
combustion may lead to a buildup of soot
deposit and the risk of fire.
48. Effect On Steam Boilers
Leads to starting failures and more frequent
flame failures
May lead to increased soot formation and
consequent fouling of the boiler and exhaust
system.
Solution Recomended: Follow detailed advice
given by manufactures on procedures to follow
when switching fuel qualities.
49. FFUUEELL LLUUBBRRIICCIITTYY
Ultra Low Sulphur Diesel (ULSD) contains
<15ppm sulphur.
Inherent lubricity of such diesel is reduced
which in turn increases wear on fuel pumps
and injectors.
Solution : Lubricity additives are commonly
added at source to such fuels to reduce these
problems
50. EENNGGIINNEE EEXXHHAAUUSSTT DDEEPPEENNDDSS
UUPPOONN
ENGINE TYPE ( i.e LOW,MEDIUM AND
HIGH SPEED)
ENGINE SETTING ( i.e LOAD,SPEED AND
FUEL INJECTION TIMING)
FUEL USED
51. FFAACCTTOORRSS AAFFFFEECCTTIINNGG
NNOOxx FFOORRMMAATTIIOONNSS
SPEED OF ENGINE
MAXIMUM TEMPERATURE
INSIDE CYLINDER
COMPRESSION RATIO/PEAK
PRESSURE
AMOUNT OF SCAVENGE AIR
57. WWAATTEERR AADDDDIITTIIOONN TTOO FFUUEELL
UNDER RESEARCH WITH 30% OF
WATER IN FUEL
30% REDUCTION IN NOx EMISSION
EFFECT ON ENGINE COMPONENTS IS
NOT KNOWN
DECREASE MAXIMUM TEMPERATURE
INSIDE CYLINDER
HIGH SPECIFIC HEAT
59. MMOODDIIFFIICCAATTIIOONNSS IINN
CCOOMMBBUUSSTTIIOONN PPRROOCCEESSSS
INJECTION TIMING RETARDATION
INCREASE IN INJECTION PRESSURE
OPTIMIZATION OF INDUCTION SWIRL
MODIFICATION OF INJECTOR
SPECIFICATION
CHANGE IN NUMBER OF INJECTORS
64. CCHHAANNGGEE IINN NNUUMMBBEERR OOFF
IINNJJEECCTTOORR
COMBUSTION PROCESS CAN BE
CONTROLLED BETTER
REDUCE MAXIMUM COMBUSTION
TEMPERATURE
ADDITIONAL COST OF FUEL INJECTOR
AND PIPING
INCREASE IN MAINTENANCE COST
30% REDUCTION IS ACHIEVABLE
65. SSCCAAVVEENNGGEE//CCHHAARRGGEE AAIIRR
CCOOOOLLIINNGG
14% REDUCTION IS POSSIBLE BY
LOWERING CHARGE AIR TEMP. FROM
40oC to 25oC
REDUCE COMBUSTION TEMPERATURE
SUITABLE FOR MEDIUM AND HIGH
SPEED ENGINES
COOLING AIR TOO MUCH COULD LEND
TO COMBUSTION PROBLEMS
66. WWAATTEERR IINNJJEECCTTIIOONN
DURING COMBUSTION THROUGH
SPECIAL INJECTOR
REDUCES THE BULK TEMPERATURE OF
COMBUSTION
40% REDUCTION IN NOx EMISSION IS
ACHIEVED
70. WWHHAATT IISS SSCCRR??
SELECTIVE CATALYST REDUCTION IS
THE PROCESS OF REDUCING NOx
COMPOUNDS WITH AMMONIA INTO
NITROGEN AND WATER VAPOURS IN
PRESENCE OF CATALYST.
71.
72. SSCCRR SSYYSSTTEEMM CCOOMMPPOONNEENNTTSS
REDUCTANT STORAGE TANK
PUMP
VAPORIZER (NOT IN CASE OF
ANHYDROUS AMMONIA)
MIXER
INJECTION NOZZELS
CATALYST CHAMBER
73. WWOORRKKIINNGG OOFF SSCCRR SSYYSSTTEEMM
AFTER TREATMENT TECHNIQUE
REDUCTANT(AMMONIA) IS INJECTED
AND MIXED INTO EXHAUST
PASS THIS MIXTURE THROUGH
CATALYST CHAMBER
TEMPERATURE OF CATALYST
CHAMBER SHOULD BE 450K-720K
83. EMISSION TRADE
Credit based system
This system was proposed by the swedish ship
owners association.
Large combustion installations are capped by
their maximum annual emissions.
Installation that emits less than its allocated
credits can trade the difference in the
emissions market.
84.
85. HOW IT WORKS?
Emission reductions become a tradable
commodity, which can be bought and sold like
any other product in the market.
Each ship will be allocated points depending
on its yearly emissions in tons.
Trading can be made anonymously through an
emissions market.
86. CONCLUSION
Emission control is a necessity to make
shipping transport viable.
CSR and Green marketing are the new buzz
words.
One time investment and high returns.
Decrease in peak temperature can limit NOX
emission.
Limit SOX by removing sulphur prior
combustion.
87. REFERENCES
Reduction of NOx and SOx in an emission a snapshot of
prospects and benefits for ships in the northern European
SECA area.
www.imo.org
MARPOL consolidated edition 2006
Exhaust emissions from ship engines - significance,
regulations, control technologies by Laurie Goldsworthy
www.dieselnet.com