slide presentation lng carrier

8/10/2019 Slide Presentation LNG Carrier

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GROUP MEMBER:

MUHAMMAD ALIFF IRFAN BIN MOHD SUHAIMIMUHAMAD RIDHWAN BIN KHAIRIL ANUARMUHAMAD SYAMIL HILMI BIN BAHARAM

MUHAMAD FIRDAUS BIN ISMAILMOHD ZUHER BIN ZAKARIA


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INTRODUCTION


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Nowadays, the global demand for energy is increasing.

The expansions in the global demand for natural gashave opened up a new chapter of gas field development.

The LNG ship has becomes the most important ship

that was uses to transport all the gas.

The LNG carrier has different design compare to othership due to their functions.


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To study about the design and production processrelated to production of LNG carrier.

To determine the difference between LNG carriercontainment system

To identify how the material selected and testing forconstruction of LNG carrier


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This study is necessary in order to find the process related to

production of LNG (natural gasses) carrier production which is

stated in our objective. Besides that, students can know the

difference between LNG carrier containment system and way to

identify the material selected and testing for construction of

LNG carrier.


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LITERATURE REVIEW


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The story of LNG shipping is a tale of massive investment, sophisticated

technology, engineering wizardry and repeated efforts to tame the ocean's

mayhem. It's a fast-growing industry that connects a mix of sellers, buyers,

middlemen, financiers and engineers. Worldwide, ships carried more than 11.5 trillion cubic feet of natural gas as

LNG in 2013, however it's only enough to supply the entire United States

for nearly half a year During 2013, about 360 LNG tankers were in service. They averaged

150,000 cubic meters in capacity, which is enough gas to supply some

42,000 U.S. homes for a year.


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In January 1959 Methane Pioneer, a converted World War II

freighter containing five aluminum prismatic tanks, carried a

liquefied natural gas cargo from Lake Charles, La to Canvey Island,

United Kingdom. The LNG industry started in 1964 with the first shipment from

Algeria to the UK. The first gas carrier tanks that were uses in continuous regular

trade in United States were of the membrane tank design. In 1999 Samsung Heavy Ind. successfully constructed the worlds

largest New Membrane-type LNG carrier, which was the largest

single hull-form vessel in the world at that time.


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Natural gas is a mixture of hydrocarbons which, when liquefied, form a clear

colorless and odorless liquid.

Its usually transported and stored at a temperature very close to its boiling point at

atmospheric pressure (approximately 160 degree C).

LNG is very cold liquid form of natural gas and fuel that's burned in gas stoves,

home heaters, and electric power plants.

When it warms back up, LNG becomes natural gas again. LNG does not burn itself

but needs to be in vapor form and mixed with air to burn.


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SHIP BUILDING PROCESS

(LNG CARRIER)


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The ship design process starts with deciding the mission requirements.

These are usually specified by the ship owner, who based on thecurrent and future market scenario and expectations, define theparameters and features of the ship.

A concept design should, from the objectives, provide sufficientinformation for a basic techno-economic assessment of thealternatives to be made.

Economic criteria that may be derived for commercial ship designs andused to measure their profitability are net present value, discountedcash f low, or required freight rate.


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After all the preliminary design has been selected, there are followinginformation that must be available:

1. Dimension: The dimension of the ships are mostly important and itprimarily influenced by the cargo-carrying capacity of the vessel.

2. Displacement: The addition between the light weight and the deadweightof the ship.

3. Stability: T he statically stability is always be consider in order to ensurethat this is sufficient in all possible conditions of loading.

4. Propulsive characteristic and hull form: A better propulsiveperformance will ensure that the vessel attains the required speeds.

5. Preliminary general arrangement: The general arrangements for LNGcarriers have a similar overall arrangement to tankers in that their

machinery and accommodation are aft and the cargo containment isspread over the rest of the ship to forward where the forecastle is fitted.6. Principle structure detail : The standard of classification specified will

determine the structural scantlings and these will be taken out by theshipbuilder.


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For LNG carrier, there are several main principles governing the design of hull to ensure

the effective productivity of the ship.

A double hull concept with a large deck area: A rather shallow draft wasselected for the LNG carrier so as to provide a large deck area for the liquefaction

process plant and to allow the complete construction of the ship in a single location

Longitudinal storage tanks: T he tanks are partially filled most of all the time whether it fill with liquefied natural gasses or ballast, the tanks are arranged in a

longitudinal manner because It allows a high transverse stability with negligible free

surface effect


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Its very important due to the liquefied natural gasses that they will

carry out.

The design of tank must have a characteristic that can avoid from

the natural gasses are not become a gasses during transportation.

There are two design of tank which is dominantly uses for natural

gasses storage which is Moss and Membrane.


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Moss Tanks Membrane Tanks

Heavy rigid metallic

High material & fabrication costs Specialized, light construction

High material & fabrication costs

Tanks capacity 125,000 m 3

Ship tank material weight: 4000 tons Tank capacity 125,000 m 3

Ship tank material weight: 400 tons

Insulation: non load bearing relatively

cheap Insulation: rigid load bearing over whole surface

relatively expensive.


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The hull and tanks are independent structures and self-supporting tanks are arrangedinside the hull.

So, the deformation due to thermal expansion and contraction is not directlyconveyed to the hull.

The liquid cargo load in the tanks acts on the self-supporting tanks, not directly onthe insulation material, and all loads act on the tank supporting members.

Therefore sufficient strength and insulation performance are required for thesupporting structure.

Secondary barriers are required to be installed from the viewpoint of hull protectionagainst leakage of LNG in an accident emergency.


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The insulation material is installed on inner hull and its surface is covered with a

metallic membrane sheet.

This containment system aims at reducing the metallic material exposed to low

temperatures.

The cargo liquid load acts directly on the hull via the insulation material, therefore

the insulation structure must have not only insulation performance but also

strength.

The membrane keeps liquid-tightness to prevent cargo leakage, and has no strength

against cargo load. There are two different type of membrane tank which is Gaz Transport and

Technigaz


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The main features of this containment system are made by orthogonalcorrugations low carbon stainless steel.

1.2 mm thick stainless steel waffle membrane Corrugations absorb the thermal contraction and ship movement stress

Fiberglass insulation within balsa wood panels bounded by plywood sheets Mk I

system (balsa wood now replaced by PVC/PUF foam sections Mk III system)

Inner balsa wood or Triplex laminate provides secondary barrier Corrugations and insulation spaces kept inert in service

Suspended tower framework for pumps, piping etc.


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The main features of this containment system, made by flatsurface with ridges, are:

Two 0.7 mm Invar membranes No need to compensate for thermal contraction

Invar - 36% iron-nickel alloy 63% Fe - very low thermal expansion

coefficient Insulation consists of layers of plywood boxes filled with perlite

Insulation spaces filled with inert gas in service

Suspended tower framework for pumps, pipes etc.


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In the Gaz Transport GT96 design, the inner hull which is the outer shell of each of the

cargo tanks, is lined internally with the patent of tank containment and insulation

system. This consists of the following:

A thin flexible membrane, called the primary membrane, which is in contact with the cargo.

This is fabricated from Invar and has a typical thickness of 0.7mm.

A layer of plywood boxes filled with Perlite, called the primary insulation, typically of

approximately 230 mm thickness.

A second flexible membrane similar to the first one, called the secondary membrane. Also of

Invar and having a typical thickness of 0.7mm.

A second layer of boxes, also filled with Perlite, and in contact with the inner hull, called the

secondary insulation. This layer is typically of approximately 300 mm thickness.


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ERECTION.Erection process is where the blocks are joined together in the dock and seated onthe dock keel blocks which are arranged according to hull form and then it will be welded.In erecting the ship units, it is important to employ the correct welding sequences.These are arranged to avoid excessive locked in stresses. Locked in stress is the release of internal strain energy at some part of the ship after welding.The ship also has to be fully faired and welded.The fairness of the hull form required to improve hydrodynamic performance andproductivity characteristics.These structures are covered for gaps and spaces between parts of the ship withaccurate and precise welding to reduce form drag and interference drag, and toimprove appearance.Nowadays, modern shipyards may employ or use automatic welding processes where it can be required.


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The figure shows the erection sequence for double hull tanker.


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LAUNCHING.Launching involves the transference of the weight of the shipfrom the keel blocks on which it is supported duringconstruction, to a cradle on which it is allowed to slide into thewater.

Normally the vessel is launched end on, stern first.

Shipyards usually located on rivers or narrow channels areobliged to launch sideways.

Stability calculates very important in doing the sidewayslaunch.


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Reinforced berths are relatively solid and reinforced with piles toallow them to sustain the weights of ships built upon them.

Weight of vessel taken by keel blocks, shores & bilge

During building, the keel blocks take the greater part of the weight, the remainder being carried by shores, and where it usedbilge blocks.Foundations under the specific positions of grounds ways shouldalso be strong structurally since during a launch the ways aresubject to large pressures.


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Pre Outfit and OutfittingPre-outfit

installing piping, electricalcomponents and othersystem components in the

panels, sections and blocksmaking up the hullstructure.

performed inside thespecialized and well-equipped workshops withideal lighting .

Outfittingcontinues activities, which have not yet beenfinished in the previouspre-outfitting stage orembarks on newactivities that can only

be done during the hullerection or afterlaunching.


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Ventilationto prevent damage of cargo because of moisture, shipsare fitted with natural or forced ventilation systems. All components of ventilation systems such as fans,motors, ducts, air intakes and outlets and filters must work properly in order for the systems to operatesafely.

proper ventilation system design and equipmentselection can minimize shipboard noise problems andat the same time enhance the service life of equipment


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cargo tank ventilators in entirely separate from airpipes from the other compartments so that flammable vapor emissions cannot be admitted to other spacescontaining source of ignition.


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Refrigeratoris the process of removal of heat from componentssystem or spaces in order to maintain them at thetemperature lower than the ambient.play a vital part in carrying refrigerated cargo andprovisions for the crew on board.The main purpose is to avoid any damage to the cargo

which carry Liquefied natural gas(LNG) so that thecargo in transported in good and healthy condition


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Pumping and pipe arrangementGeneral services pipes and pumpingprovided with pumps and substantial piping system tosupply essential services of hot and cold fresh water forpersonal use, and salt water for sanitary andfirefighting purposes.The sanitary system supplies sea water for flushing

water closets


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Air and sounding pipesprovided with air pipes to prevent air being trappedunder pressure in the tank when it is filled.Sounding pipes are small-bore mild steel pipes used toallow the measuring equipment to enter a tank or aspace.


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Corrosion Control and Anti-fouling

System (Painting)Cathodic protection Protective coating (paints)

Sacrificial anode -sacrificialanodes are metals or alloys

attached to the hull which havea more anodic, less noble andpotential than steel whenimmersed in sea water.Impressed current -applicableto the protection of theimmersed external hull only.

Voltage difference is maintainedbetween hull and fitted anodes,

which will protect the hullagainst corrosion.

to protect against corrosionconsist of pigment dispersedin a liquid


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Anti-fouling systemimmersed hull today are finished with very effective self-polishing anti-fouling paints. Why??particularly in coastal waters, are subjected to algae,barnacle, mussel and other shellfish growth that canimpair its hydrodynamic performance and adversely affectthe service of the immersed fittings.

regulations limiting the release rate of tributylencompounds(TBT) for antifouling paints on larger ships dueto had a harmful effect on certain marine organisms. Henceuse of copper-based self-polishing antifouling products.

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