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AY 2011/2012 B.Eng in Naval Architecture MAR3102- PROJECT A Literature Review on A STUDY OF LNG BUNKER DESIGN ONBOARD TANKERS VANESSA LIEW NU 109257518 Table of Content
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AY 2011/2012

B.Eng in Naval Architecture

MAR3102- PROJECT

A Literature Review onA STUDY OF LNG BUNKER DESIGN ONBOARD TANKERS

VANESSA LIEW NU 109257518

Table of Content

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1 Problem Statement...........................................................................................................2

2 Background.......................................................................................................................2

2.1 Advantages of LNG.....................................................................................................3

2.2 Disadvantages of LNG................................................................................................3

3 Literature Review..............................................................................................................4

4 References........................................................................................................................ 9

5 Appendix.........................................................................................................................10

A. Nomenclature................................................................................................................10

B. Capability........................................................................................................................10

C. Aims and Objectives.......................................................................................................11

D. Project Methodology and Work Packages.....................................................................11

E. Deliverables....................................................................................................................13

F. Resource Requirement...................................................................................................13

G. Schedule of Work.............................................................................................................0

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1 Problem Statement

At present, most of the merchant vessels operating as fully-LNG fuelled ships are classified as non-tankers. I.e. Container ships. From prior research done, tankers burning purely LNG fuel have not been in the market yet.

The motivation for this project arises because the author believes that for new fuel for ships, new designs should be considered. For example, because an LNG-fuelled vessel is no longer burning HFO, there may not be a need for double bottom tanks anymore.

2 Background

Currently marine vessels run on either Marine Diesel Oil (MDO) or Heavy Fuel Oil (HFO). Of these two, the latter is more popular because it is generally a lot cheaper and because of its popularity, it is very convenient to take up bunkers because of the availability of bunkering terminals for HFO worldwide.

Burning HFO however, does have its downsides. From 2005 up till present, MARPOL1 has been coming hard on emissions. Emission Controlled Areas (ECAs) and Sulphur Emission Controlled Areas (SECAs) have been established in the USA and increasing waters of the European Union. This means that ships with that do not comply with the upcoming emission standards of CO2, SOx∧NOx will not be able to sail within these areas.

Many solutions have been offered to remedy this problem, and most of them still involve the use of the cheap, environmentally damaging HFO. Some methods of tackling the problem include installing scrubbers in the exhaust, which promises to remove up to 80% of the emissions, as well as burning low sulphur fuel oil. This means that the major changes are done to the ship, not the fuel. However, it should be noted that these solutions do not completely get to the root of the problem, and while MARPOL intends to totally eliminate SOx∧NOx by 2016, the future of HFO is beginning to look bleaker and bleaker.

This has caused shipping companies to rethink the future of HFO and look for other fuel alternatives. One of the most promising alternatives which has already been in place for a few years is Liquefied Natural Gas (LNG). According to DNV, as of the end of November, there was about 21 merchant ships that were burning LNG fuel. It is also estimated that by 2020, most owners would state LNG fuel tanks as a requirement when they request for new-builds.

1 Annex VI: International Convention for the Prevention of Air Pollution From Ships

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2.1 Advantages of LNG

As highlighted above, one of the biggest advantages burning LNG has over HFO is that it is the cleanest of all fossil fuels. In addition to eliminatingSOx emissions and reducing up to 80% of NOx, it has a small carbon footprint.

In recent years, engineers have developed a duel-fuel engine. i.e. able to burn HFO and LNG. This was developed so that ships were still able to operate in ECAs by doing a fuel-oil-changeover to LNG. In addition to this fuel flexibility, another advantage is that LNG bunker tanks and engines can be retrofitted onto existing vessels. Lastly, because there are already ships operating exclusively on LNG in Norway, it makes converting to LNG a more reassuring and viable option for ship owners.

2.2 Disadvantages of LNG

The obvious disadvantage of LNG is the price compared to HFO. However, because the pricing of LNG fuel is based on long term contracts, the LNG fuel price is not market driven.

A higher initial capital cost for a LNG-fuelled propulsion system compared to conventional diesel engines may deter ship owners initially.

In addition, because LNG vessels are still relatively new to much of today’s crew, additional costs will be incurred to send the crew for training. Downtime for the crew to be familiarised with the engine will have to be considered as well.

The LNG market is dominated by very few suppliers worldwide. As such, one of the biggest challenges of converting to LNG fuel is the availability of bunkers. Because the LNG infrastructure is not as well established as conventional bunker fuel structures (HFO and MDO), the LNG bunkering process is not as convenient. To counter this, marine engineers have come up with and put to work a ship-to-ship bunkering concept.

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3 Literature Review

BANAWAN, GOHARI and SADEK (2010) did an analysis on the environmental and economic benefits of moving from MDO to LNG fuel. In this study, it was established by the authors that short voyage trips with high power ratings would be most suitable for LNG applications in order to obtain the maximum environmental and economic benefits. The vessels applicable to their study were high powered passenger ships. In this report, they mentioned that LNG “a higher adaptability than other marine fuels, with emphasis on reciprocating engines.” In the latter part of his journal article, a comparison was made for the annual cost of fuel consumption between diesel engines and dual fuel engines. The comparison table is included below:

Fig 1-1: Comparison table showing differences in diesel and dual fuel engines

The result of the cost benefit analysis was that switching LNG fuel would save a significant amount. One of the more relevant points the author included was that in the report, the authors considered TVS-54-60 bunker container models, which is parallel to IMO 7 (Cryogenic gases) tanks.

Author’s comments: As one of the first articles I reviewed, I felt that this was an informative article which broadened my perspective on LNG. The cost benefit analysis justifies the global switch from HFO to LNG. For this article, the authors included: fuel cost, maintenance cost and conversion costs. I felt that the analysis could have been improved if the team had considered subtler factors such as the cost for training the crew as well as the economic losses during the downtime needed for installing the dual-fuel engine. In addition, more explanation could have been given to help the reader understand why the economic and environmental benefits are maximised for short voyage trips and not the longer voyages, which are applicable to tanker routes.

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BRETT (2008) sought out the feasibility of LNG-fuelled vessels in the US. Through the span of her research, she listed the possible applications for LNG-fuelled vessels. Some of those she listed included are: Ferries, cruises, offshore supply vessels, harbour craft and short sea shipping, with well-defined routes, for domestic transportation of commercial freight.

Fig . 1-2: Global LNG importers and their markets (2006)

One of the highlights of the report included the bunkering possibilities for an LNG cruise. In summary, she said that because the cruise ship does not go to port every 24 hours, it would require a bunker tank with larger capabilities. She concludes the report by saying that for LNG to take flight and be further accepted by the US as an alternative fuel, more safety and security concerns would have to be addressed to change the public’s conception of LNG.

Author’s comments: I felt that this was a very useful and well written article, although one might get a feeling that the author might have been a little bias toward promoting LNG and less keen in highlighting the factors hindering the growth of LNG infrastructure in US.

In general, I was disappointed that Ms Brett did not (Anderson, et al., 2001) put down more information regarding the barge vessel-to-vessel transfer of LNG fuel. This concept may be a good way to expedite the development of LNG infrastructure around US and the rest of the world. Although the author listed the various methods of LNG bunkering, I was hoping that she would pick up and predict which methods might be more workable and easier to implement with respect to the US.

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ANDERSSON and WINROTH (2010) investigated the potential for LNG fuel shipping with regards to short sea voyages in East Asia. The reason for their study was because Asia is home to the largest sea borne trade, especially container shipping, in the world (Stopford, 2009). One of the valid points that the authors made regarding the competitiveness of LNG as an upcoming fuel was that being emission-reducing will not be good enough for owners to consider it. Other factors such as fuelling capacity, capacity and speed and flexibility also play huge factors.

The authors then made their knowledge of LNG fuelled shipping applicable to the Asia context and continued to expound on container shipping. The latter part of this thesis looks at the various major ports and LNG infrastructure in Asia, naming Shanghai, Singapore, and Hong Kong as the busiest ports in the world.

Author’s comments: The authors didn’t give an estimate as to which year they might see the LNG infrastructure coming to life in East Asia. From an Asian standpoint, because we are a conservative people, I personally feel that unless the US and EU begin using LNG as bunker fuel, Asia will not see reason to follow suit. Other than that, I think that LNG will be a really good fuel alternative for Asia. This is because as China commercialises and becomes more open to trade, we would expect to see more voyages between the Asian countries, therefore these short sea shipping options could work out in the near future. Overall, the points raised about LNG as a fuel is agreeable with what the other articles have mentioned, i.e.

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ANDERSON, TURAN and SEMERCIGIL (2010) studied the effects of sloshing in a cylindrical container. In the article, they mentioned that “Liquid sloshing can cause loss of dynamic stability and manoeuvrability of the transportation vehicle”. In the first part of the article, they evaluated past methods other authors have done previously to counter sloshing, and these methods include:

I. Momentum of liquid in an inverted U-tubeII. Submerged blocks and plates placed strategically along the cylinder

III. Actively injecting air bubbles in the liquid

Considering the above methods, the 3 authors presented their idea in the form of using dumbbell type controllers.

Fig 1-3 Showing the equilibrium positions of the dumbbells when the bottom plate is (a) floating on the surface, (b) immersed in liquid.

They then carried out experiments to determine the effect of mass ratio at different gaps of the bell plates with varying ratio of separation distance between the dumbbell plates to the static water height.

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Fig 1-4 Effect of mass ratio on the sloshing wave at different gaps of dumbbell plates (S) of 0.26 and 0.65

The results revealed that increasing the separation distance gave an improved control effect. The final conclusion of this experimental research is that the dumbbell type controllers were an inexpensive and versatile passive control to reduce the sloshing amplitude. The authors held high hopes for this controller-type to have practical applications.

Author’s comments: While this could be a practical and viable solution to implement on normal liquids, it is not known if this controller type is suitable to be applied with cryogenic liquids. This is because although this dumbbell type controller effectively damps out the sloshing amplitude by as much as 80% in normal fluids, installing it into LNG tanks causes more surface area for friction. When the ship rolls, this friction is likely to generate sufficient heat to cause a greater percentage of bunkers to boil off.

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4 References

Anderson, J. G., Turan, ö. F. & Semercigil, S. E., 2001. Experiments to Control Sloshing in Cylindrical Containers. Journal of Sound and Vibration, 240(2), pp. 398-404.

Andersson, H. & Winroth, C., 2010. Potential and Conditions for LNG Fueled Short Sea Shipping in East Asia, Göteborg: Chalmers University of Technlogy.

Banawan, A. A., Gohary, M. M. E. I. & Sadek, I. S., 2010. Environmental and economical benefits of changing from marine diesel oil to natural-gas fuel for short-voyage high-power passenger ships. Journal of Engineering for the Maritime Environment, 224(103), pp. 103-113.

Brett, C. B., 2008. Potential Market for LNG-Fueled Marine Vessels in the United States, Massachusetts: Massachusetts Institute of Technology.

Harsema-Mensonides, A., 2010. Dual Fuel Electric Propulsion Systems in LNG shipping, 2010: MPT Consultancy.

M., S., 2009. Maritime Economics. 3rd ed. Abingdon: Routledge.

Nightingale, A., 2010. Bloomberg. [Online] Available at: http://www.bloomberg.com/news/2010-11-19/liquefied-natural-gas-to-dominate-ship-fuel-in-40-years-det-norske-says.html[Accessed 7DEC2011 December 2011].

Pitblado, R. M. & Woodward, J. L., 2011. Highlights of LNG Risk Technology. Journal of Loss Prevention in the Process Industries, Issue 24, pp. 827-836.

Shivam Shipping Services, 2006. Tank Services. [Online] Available at: http://www.shivamship.com/tank-services.htm[Accessed 9DEC2011 December 2011].

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5 Appendix

A. Nomenclature

LNG : Liquefied Natural Gas

MDO: Marine Diesel Oil

HFO : Heavy fuel oil

DNV: Det Norske Veritas

MARPOL: Marine Pollution

B. Capability

This thesis is relevant to the marine industry, particularly affecting LNG fuelled powering. The student will be carrying out this design study under the guidance of project supervisor Dr Jonathan Downes.

Dr Downes has previously worked on a project Structural Performance of Aluminium Naval Vessels which dealt with aluminium. Because this project will deal with the impact loadings, his expertise will be very valuable. In addition, Dr Downes was also a senior researcher in the ALERT (Assessment of Life-cycle Effects of Repairs on Tankers). His vast experience and insight on structural strength on tankers will be especially helpful when assessing the effect of sloshing loads.

With regards to the design capabilities, the student will be consulting Mr Zhou YiLi, a senior lecturer and deputy course manager at Ngee Ann Polytechnic. Mr Zhou, who has very kindly agreed to act as a consultant for this design project, is also the AVEVA module lecturer for NUMI Singapore and has many years of experience working on the software.

While in NUMI Singapore, the student will have access to the online resources provided by the Newcastle University library via https://ras.ncl.ac.uk. While students in Singapore do not have access to the Robinson library in Newcastle, the facilities in Ngee Ann polytechnic such as the library, computer labs and project rooms are provided should a need for these resources arise.

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C. Aims and Objectives

The aim of this thesis is to provide a design alternative for LNG bunker designs for tankers. By the end of this project, the student will aim to answer the following questions:

1. What will the completed tanker look like and how stable is this design with LNG bunkers?

2. Can anti-roll technology be implemented on the LNG bunker tanks to decrease the sloshing effect?

The objectives of the author’s study are listed as follows:

i. To identify suitable LNG bunker containment on the tanker (type, tank capacity)ii. To determine the location of the bunker tanks (for optimised stability without

compromising on safety)iii. To study the effect of sloshing and possibly suggest ways to minimise the sloshing

loadiv. To produce a general arrangement drawing of the final recommended design

D. Project Methodology and Work Packages

Stage 1: Problem definitionThe very first stage of every design project is identifying a current problem which needs to be addressed. In this stage, the author will take into consideration that the problem statement should only be focused on one problem, and that it is at most one or two sentences long.

Stage 2: Planning and data collectionThe second stage of the project encompasses planning and conceptualization. Having established the basis of the deliverable outcome of this project, it is necessary to gather information to support the latter part of this design project. Firstly, it would be important to establish that LNG as marine fuel will continue to be a viable option for the marine industry, and investigate how LNG has already been implemented as bunker fuel.

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There are a number of ways to gather this information, and one of the ways is to go through engineering databases (IEEE, Science Direct, EBSCO) and compile relevant journal articles or conference proceedings. From the information there, a broader perspective of LNG bunkering will be gained. The second way to collect data would be to peruse through engineering books related to LNG to gather field specific data required for this project. The final method of the planning phase would include looking at the relevant class society (DNV) rules already established to ensure that the generated initial designs comply with the class rules. For effective data collection, information filtering will be vital. This means that redundant, obvious bias, or unwanted information will be sieved out. Information filtering will ensure that the information input remains objective and reliable.

Stage 3: Setting practical goalsAt this stage of the project, it would be wise to set specific goal-oriented deadlines. A work schedule should be drawn up to keep track of progress and manage the time frame allocated for this project. The entire sum of work anticipated should be broken down into work packages(work breakdown structure) which further expounds into specific deadlines. This is to give a macro view of the work to be done as well as set milestones for the project. (E.g. Completing the literature review; Getting familiarised with AVEVA software).

Stage 4: Application and designThis stage of the project commits to applying the knowledge that the student has accumulated in the planning stage and putting into practice. The student will begin practising the design software, AVEVA and get familiar with the software functions.While exploring, the student should be innovative, constantly keeping in mind that the final design should be novel.

Once familiar with the software, an initial design should be drafted and the loading conditions (fully loaded departure/arrival and ballast departure/arrival) simulated. From there, the software will be able to generate stability calculations, as well as initial drawings of the vessel.

Stage 5: Analysis and discussion of resultsIn the final stage of this project, the student will review and consolidate the project as a whole from beginning to end. This includes the findings, drawings, data collected etc. The student should be able to discuss the result findings and make comments in retrospect.

Stage 6: Report compilation and ReferencingWhile doing referencing is not an actual work package or stage of work, the student should make continuous, conscious efforts to keep track of information used to prevent plagiarism. Newcastle university adopts the Harvard style of referencing. All references should be correctly cited and compiled into a bibliography at the end of the report.

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E. Deliverables

On the deadline 6th May 2012, the following articles are to be submitted:

I. General arrangementII. Stability calculations

III. Final schedule of workIV. Final report

F. Resource Requirement

For this project, the anticipated resources required include databases. These include engineering databases like IEEE, EBSCO, Science Direct. Another requirement on the list is the software AVEVA, which as previously mentioned is accessible in the Ngee Ann Polytechnic campus. Any data in the form of books, journals or conference proceedings regarding tanker design, use of LNG as fuel and stability assessment would be handy.

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G. Schedule of Work

9 Stage 3 - Setting Practical Goals

Exam

Wee

k10 T3.1 - Breaking down work into work packages11 T3.2 - Draw up a project work breakdown structure (PWBS)

12 Stage 4 - Application and Design13 T4.1 - Familiarising design software, AVEVA 4 sessions AVEVA lessons

4 sessions AVEVA lessons

14 T4.2 - Drafting of initial design15 T4.3 - Check that design complies with class specification16 T4.4 - Generate initial stability assesment17 T4.5 - Input 4 critical loading conditions and comsumables

25 Stage 5 - Analysis and Discussion of Results26 T5.1 - Analyse critically what values mean27 T5.2 - Identify the difference LNG bunkering has from conventional bunkering 28 T5.3 - Provide discussion of results

29 Stage 8 - Report Compilation30 T7.2 - Draft of final report

Legend

TargetActual

25262728

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