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My first presentation in my life was about container ship in my first year at college in department of Marine and Naval Engineering hope to add some information to you about container ships
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Modern technologies for efficient propulsion & fuel saving (by dwivedi)anand dwivedi
above paper consist information of all latest and upcomming technology to improve propulsion efficiency of ship.it deals with technologies which has been installed in many ships across the globe for fuel saving.
special thanx to chetan shivans randev, hari krishna malil & gaurav gosain.
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Similar to Portable Fuel Tank - The Application of a New Method of Bunkering for Small Scale Gas Fuelled Vessels(compressed) (20)
Portable Fuel Tank - The Application of a New Method of Bunkering for Small Scale Gas Fuelled Vessels(compressed)
1. No part of the materials published in this journal may be reproduced, stored in a retrieval system or transmitted in any form whatsoever without the prior written permission of KOMtech
Portable Fuel Tank - The Application of a
New Method of Bunkering for Small Scale Gas Fuelled Vessels 79
Portable Fuel Tank - The Application
of a New Method of Bunkering for
Small Scale Gas Fuelled Vessels
XU Junwei Kelvin, B.Eng
Abul BASHAR, BSc Eng
Sreekala KUMAR, B.Tech
Nigel KOH, BEng, MSc, PhD
THIS PAPER PRESENTS THE APPLICATION OF A NEW METHOD OF
BUNKERING FOR SMALL SCALE GAS FUELLED VESSELS in which a portable
LNG tank is used as the ship’s fuel tanks. The bunkering could be a simple
procedure as replacing the empty tanks with preloaded fuel tanks which are
transported by truck, ship or rail. This can greatly reduce the overall bunkering
duration and ship will be no longer required to travel to remote designed shore
facilities for bunkering. This bunkering method has been adopted in the KOMtech
Ocean-going/Harbour LNG Fuelled (Dual Fuel) Tug design. This is achieved
through a carefully designed and well-utilised deck layout without reducing the
accommodation spaces, maintaining the vessel within the 500GT cap to avoid
more implementation from SOLAS regulation.
2. 80 KOMtech Technology Review 2016
INTRODUCTION
As many LNG terminals over the world are either still
under-development or planning for development,
the supply of LNG for use as marine fuel via shore
based terminals can be an issue. Other bunkering
methods such as ship-to-ship, LNG bunker vessels
(carrying dangerous cargo) are restricted to entering
non-Petroleum harbour areas lest with authorized.
Additionally, the industry is hesitant to invest in
such vessels due to its high investment costs and
limited alternative operations when LNG bunker
demand is limited.
Due to lack of fully developed LNG bunkering
infrastructure, the most preferred method will
be perhaps either the conventional truck-to-ship
bunkering method or the portable fuel tank transfer
which is adopted in the KOMtech LNG fuelled
tug. Both methods are best suited for smaller-sized
LNG-fuelled vessels with up to 90m3
tank capacity
due to the limited capacity of trucks with 44.5 m3
and LNG is only to transfer at a low rate. Refer to
Table 1.
PORTABLE FUEL TANKS – APPLICATION
ON A LNG FUELLED (DF) HARBOUR TUG
KOMtech has introduced the use of portable tanks as
primary fuel tank on a 32m tugboat. The cryogenic
Table 1. Comparison of LNG bunkering method for inland vessel
Description Shore-to-ship Ship-to-ship Truck-to-ship Portable tank
transfer
Operation Cost High Very High Average Average
Maintenance Cost High Very High Average Low
Personnel Training Yes Yes Yes Only Ship Crews
Affect Other Trade Yes Yes Yes Yes
Ship Shore Link
(with ESD)
Yes Yes Yes No
Bunkering Time
(for 40m3
filling at
low rate)
Max. 55 min Max. 45 min Max. 80 min *Max. 30min
Bunkering Rate 60 ~ 1000m3
/hr 80 ~ 500 m3
/hr 35 ~ 60m3
/hr NA
Capacity Up to 2000m3
Up to 1000m3
45m3
(each) 20m3
~ 40m3
(each)
Suitable Ship Scale 500 GT and above 500 GT and above 250 ≤ 1500 GT 250 ≤ 1500 GT
*Esitmated
Note: Ship to Ship bunkering process time is longer depend on sea state and weather condition. Refer to [1] & [6]
tank container (IMO - container) is arranged on the
aft deck area to avoid obstructing either the towing
operation or the visibility of the master at bridge.
This arrangement of the portable tanks on deck
does not sacrifice spaces below the main deck which
could otherwise be used as accommodation space or
engine room and also eliminates the risk of enclosed
vapour cloud explosions.
This arrangement is best suited for dual fuel vessels,
in which the diesel tanks can be arranged within
the hull and the LNG tanks can be arranged on the
deck. However, this makes the tank vulnerable to
high saline seawater which might cause corrosion of
the exposed metal over a period of time.
KOMtech – Ship & Marine Technology have
developedthedualfuelTugforworldwideapplication
as well for harbour use. Both versions are integrated
with the new hull form which is developed by MTD
(Marine & Offshore Technology) for Diesel Escort
Tug version in 2015.
The 32m tugboat is designed as dual fuelled vessel
which can run on both marine diesel oil and natural
gas. The hull tanks for the diesel oil storage has
been maintained as with its parent diesel version.
The fuel LNG is carried in two portable fuel tanks
arranged on the aft deck of the vessel.
3. Table 2. Principal Particulars of LNG Fuelled (DF) Harbour Tug.
Length Overall 32.00 m
Moulded Breadth 12.48 m
Moulded Depth 5.30 m
Design Draft 4.00 m
Extreme Draft (With Skeg) 5.40 m
Service Speed 13 knots
Bollard Pull (Astern) 65 Tons
Main Propulsion Engine 2 x 1920kW @ 800 RPM
Thruster (ASD) 2.7 m diameter
LNG Tank Capacity 2 x 20 m3
LNG System LNG Vaporizer, Buffer tank
Classification ABS +A1, + AMS, E , Towing Vessel, Fire Fighting Vessel Class 1, BP ( ),
GFS (DFD), UWLD.
Vent Mast
LNG Tanks
Bunkering Station
The main areas of interest while having a gas fuelled
vessel are the following:
1) Bunkering
2) Supply of LNG from tank to the prime mover
3) Gas venting arrangement
BUNKERING
Portable Fuel Tanks - Description
A cryogenic tank (e.g. IMO-container) comprises
a vacuum insulated container that is designed with
performance, ease of operation and safety in mind.
The cryogenic tank can store LNG. The cryogenic
tank is designed in accordance with ISO standards
and its size and dimensions ensure that the tanks
can be conveniently transported by trailers, ship and
railway. These tanks are to be certified and should
comply with International Maritime Organization
(IMO) regulations, Classification Societies and ISO
1496-3:1995(E) [4]
.
Figure 1. 3D View of the 32m LNG Fuelled (DF) Harbour Tugboat.
Portable Fuel Tank - The Application of a
New Method of Bunkering for Small Scale Gas Fuelled Vessels 81
4. 82 KOMtech Technology Review 2016
Figure 3. Plan View of the 32m LNG Fuelled (DF) Harbour Tugboat.
Figure 2. Profile View of the 32m LNG Fuelled (DF) Harbour Tugboat.
5. The structural frame around the tank helps to
protect against mechanical damage. The tank is
secured on the deck of the vessel using a twist-lock
securing mechanism that is commonly used in
container ships as illustrated in Figure 4.
The main components of the portable tanks are
mainly LNG transfer line and the pressure relief
valves.
Figure 4. Typical Portable Fuel tank and the twist lock arrangement.
Type Portable, IMO independent type C tank container
Insulation type Vacuum insulation
Size 20’ IGF ISO container
Dimensions 6,058 x 2,438 x 2,591 mm (L xW x H)
Vacuum ≤0.1Pa (Warm)
Net evaporation rate 0.34%/d (LIN) (ambient conditions: 100kPa and 15ºC
Total geometric volume Abt 20m3
MARVS (inner vessel) 1.0 MPa gauge
MAWP (inner vessel) 0.9 MPa gauge
Design pressure (outer vessel) -0.1 MPa gauge
Design temperature -196ºC
Medium density 426~470 kg/m3
Baffles Two transverse baffles
Frame material Stainless steel 304
Main materials Low alloy steel
Tare Weight 8200kg
Load Weight 8460kg
Maximum gross weight 16600kg
Vacuum design life 5 years
Production design life Not less than 20 years
Connections Quick- Coupling cryogenic hoses
Table 3. Typical Portable Tank Specification
The nitrogen on-board is used for the purging of
the pipeline to ensure gas-free before connecting/
disconnecting cryogenic hoses/ stainless steel pipe
connection. The cryogenic tank is fitted with o the
pressure relief valve when the tank pressure increased
above safe level.
Portable Fuel Tank - The Application of a
New Method of Bunkering for Small Scale Gas Fuelled Vessels 83
6. 84 KOMtech Technology Review 2016
Portable Fuel Tank Transfer –
A new bunkering method
Portable fuel tank transfer is not considered as a
typical bunkering process. The process is treated
as loading and unloading of dangerous materials.
Such operation will have to follow the stowage and
handling requirements for portable tanks containing
hazardous materials. Under CG-OES Policy letter
02-15 [7][8]
. LNG delivered in Portable Tanks fall
under the definition of “Dangerous Cargo” in
33 CFR Part 126 and must be loaded from a
designed Waterfront Facility inspected under
33 CFR Part 126.
The advantage of portable fuel tank transfer
compared to truck-to ship are mainly lesser
maintenance and operation cost (including training
of personnel with LNG handling training) and
lesser bunkering time. Additionally, there is no
requirement for vessel which adopts a Portable Tank
transfer to have the Ship Shore Link (SSL) installed
on board. However, the shore facility will need a
crane facility to transfer these tanks.
Figure 5. Truck-to-Ship LNG Bunkering.
SUPPLY OF LNG FROM TANK TO THE
PRIME MOVER
In the regasification unit, liquefied natural gas is
boiled off then to regasified to form natural gas, in
a circulation of an intermediate fluid (freshwater/
glycol mixture) between a vaporizer and ambient
air heater. The gas from the regasification unit is
supplied to the engine room through double walled
pipes. The annular space in double wall pipe is
ventilated by air/insert gas supplied either from
engine room or via pipeline outside the engine
room (to keep away from hazardous zone). This is
to ensure maximum safety in event of gas leakage.
The fuel supply from the vaporizer passes through
a buffer tank for maintaining a stable supply to the
engine to reduce the risk of knocking phenomenon
in case of not within the range of fuel quality and
temperature as recommended by engine maker.
GAS VENTING ARRANGEMENT
Excessive Pressure Build Up
The changes in temperature result in higher vapour
pressure in the tank especially if the tank is nearly
Figure 6. Portable Fuel Tank Transfer.
7. full with reduce vapour space in tank. The cryogenic
tank container is fitted with at least two lines exiting
the tank top into the pressure relief valve. In case of
excessive pressure build up, gas passes through the
lines into a main vent mast where it is vented to
atmosphere.
Maintaining a minimum safe distance of the venting
outlet from openings such as accommodation
entrances, engine exhaust outlets and others, is done
to avoid the risk of flammable or toxic mixtures
accumulating in little air movement condition and
drawn into machinery spaces or accommodation.
These vapours can be heavier than air when in cold
condition and will accumulate in bilges and other
low areas.
Commonly observed when flammable or toxic gases
can eddy and cause pockets of gas present in most
unexpected places such as the aft of the superstructure
when wind blowing from forward. The operation
profile of a tug demands frequent turning and
manoeuvring the vessel during towing, helps to avoid
the accumulation of vapors on those areas.
Vent Mast Arrangement
Hence, directing the vent mast outlet as high as the
foremast allows the vapours to rapidly disperse to
atmosphere vertically, especially in windy condition.
The vent mast outlet is directed to the foremast for
achieving a safe distance radius of 10m away from
the opening to accommodation and others. The safe
distance can be reduced to 4.5m radius as long as a
gas dispersion analysis is made to justify the risk and
in case of vapour cloud form beyond the 4.5m, a gas
detector system is to be provided to acknowledge
operator of the risk for precaution. Refer to Figure
7, hazardous zone are define as per description in
IGF-code MSC 95/WP.7 [3]
and ABS Guideline [2]
.
Protecting the areas affected by Hazard area on
vessel
Any equipment within the hazard area is to be
explosive proof certified. For example, the walkie-
talkie, navigation lights and other lights etc. The
main challenge in a small vessel like this tugboat is
how to restrict the hazard zone.
Vent Mast Exit
Figure 7. Illustration of the Hazard Area Plan.
Entrance/ exit
Zone 2
Engine room
ventilation
inlet/outlet
Tank
connection
pipelines
Engine
exhaust
outlet
Zone 1
3.0m
4.5m
Portable Fuel Tank - The Application of a
New Method of Bunkering for Small Scale Gas Fuelled Vessels 85
8. 86 KOMtech Technology Review 2016
Efficient deck and equipment layout restricting the
hazard zone to a small central area on the aft deck
is the method adopted in the design of this tugboat.
The LNG related equipment, tanks and pipelines
are carefully arranged to avoid hazard zone area for
tanks on deck. This also allows the people to work
at the wharf/berth while vessel is alongside.
CONCLUSION
The purposes of this paper is to introduce the portable
fuel tank as an efficient method of fuel storage in
small scale gas fuelled vessels and highlighting the
issues related to installation and handling of such
tanks on deck. Portable fuel tank transfer is best
suited for small vessels and in countries where facility
is far from vessel operation region or facilities still
under development. The advantage over truck-to-
ship bunkering method is the reduction in bunkering
time with minimum equipment, in a safer manner
and also eliminates the ship shore link.
The design concept have been filed for
Singapore Provisional Patent (Application no.
10201508833W) – “AN ARRANGEMNT OF
CYROGENIC CONTAINERS FOR LNG OR
CNG ON A DECK OF A TUGBOAT”.
ACKNOWLEDGEMENTS
• ABS Classification Society
• Marine Technology and Development (MTD)
We also acknowledge the information input from one of the LNG system suppliers; SHANGAI HANSAIL
MARINE & OFFSHORE DESIGN CO., LTD
AUTHOR’S CONTACT Kelvin.xu@komtech.com.sg
REFERENCES
[1] American Bureau of Shipping (ABS), Bunkering of Liquefied Natural Gas-Fuel Marine Vessels in North America 2th Edition, USA, 2015.
[2] American Bureau of Shipping (ABS), Guide for Propulsion and Auxiliary System for Gas Fueled Ships, Houston, USA, May 2015.
[3] International Maritime Organization (IMO), IGF-Code MSC 95/WP.7 Adoption of the International Code of Safety for Ships using Gases or other Low-Flashing
Point (IGF CODE), NORWAY, 10 June 2015.
[4] International Standardization Organization (ISO), ISO 1496-3:1995 (E) Series 1 freight containers –Specification and testing; Part 3: Tank containers for
liquids, gases and pressurized dry bulk, Switzerland, 1995.
[5] John L. Woodard and Rohin M Pitblado, LNG Risk Based Safety – Modelling and Consequence Analysis, Hoboken, New Jersey, John Wiley & Son INC.,
2010.
[6] Swedish Marine Technology Forum (SMTF), LNG Bunkering Ship to Ship Procedure, Uddevalla, 2013.
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