Development of SPB LNG Fuel Tank for Ships. Section of Tank (2) Concept Design of SPB® LNG Fuel...

Structure Engineering Group

Gas Project Department

Offshore and Engineering Division

Gastech 2017

Development of SPB® LNG Fuel Tank

for Ships

Contents

(1)Introduction

(2)Concept Design of SPB® LNG Fuel Tank

(3)Development of the Simplified Vibration Calculation

(4)Development of High Manganese Steel

2

(1) Introduction

(1)-1 Emission Control Requirement

3

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021

NOx Tier II Tier III （only ECA）SOx Global Cap 4.5% 3.5% 0.5%

ECA 1.0% 0.1%

ECA Coast of USA/Canada (from August)

Baltic Sea, North Sea Puerto Rico ,US Virgin Islands (Caribbean Sea)

CO2 EEDI Base △10% △20%

Source: Environmental Protection Agency (U.S.A.)

(1) Introduction

(1)-2 Use of LNG as Fuel

4

Advantage

- Emission Reduction

NOx: -80%

SOx: -100%

CO2: -25%

- LNG Price

Cheaper than Low Sulfur Fuel Oil

Disadvantage

- Increase Tank Space

Double in Fuel Volume

(= 1/2 density of heavy fuel oil)

Reduction of cargo volume

- Complexity of LNG fuel handling

- Undeveloped Infrastructure

Fuel Type SOx (g/kWh) NOx (g/kWh) CO2(g/kWh)

Heavy Fuel Oil 3.5% S 13 9-12 580-630

LNG 0 2 430-480

(1) Introduction

(1)-3 Feature of SPB® LNG Fuel Tank

SPB (Self-supporting, Prismatic-shape IMO type B)

In case of LNG fuel tank…..

5

Assumed Problem

Tank Space

LNG handling

(pressure and temperature)

Intermediate liquid level

(sloshing problem)

Damage

(accidental, fatigue etc.)

Solution

Flexible tank shape & volume

(Best space efficiency for any size & type of ships)

Easy operation and less maintenance

(Strong against outer / inner pressure)

Any level loading without sloshing

(Eliminate sloshing phenomenon by internal bulkhead)

Robust & Reliable tank system

(Proven by robust tank concept and experience)

Hull

Tank

Support

Insulation

6

(2) Concept Design of SPB® LNG Fuel Tank

(2)-1 Concept Design Study for Container Ship

Ship’s Principal Particular

Length: app. 330.0 ~ 400.0 m

Breadth: app. 45.0 ~ 65.0 m

Depth: app. 25.0 ~ 35.0 m

Container Loading Capacity 10,000 ~ 20,000 TEU

Sea Route: Far East to Europe

Range: app. 20,000 miles

LNG Fuel Tank

Capacity: 5,000 ~ 10,000 m3

L x B x D: app. 9.0~10.0m x 35.0~55.0m x 15.0~20.0m

Arrangement: In front of Engine Room

LNG Fuel

Tank SpaceEngine Room

Trans. Section of Tank


(2)-2 Development of Cost-competitive Tank

14,000TEU container ship

Rationalization (optimization) of tank structure

- Reduction of tank weight

- Increasing of machinability and construction workability

Standardization of tank support construction

- Improvement of design and construction efficiency

(divided into three patterns by assumed reaction force)

FE modelling tool

- Efficiency and Speeding up of FE modelling

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(2)-2 Development of Cost-competitive Tank

AfterBefore

10%reduction

8

14,000TEU container ship

Optimization Result of Longitudinal Girder Ring

Condition for Optimization

Target Structure Long. Girder Ring

Optimization Item Weight

Tank Material A5083-O

Tank Status Full

LNG Density 0.5 ton/m3

Vapor Pressure 0.07 MPa

Loading Condition - Static Heel Case

- Max. Trans. Acceleration Case

- Collision Case

ThicknessThin Thick


(2)-3 High Design Vapor Pressure Tank

9

Approval in Principle (AIP)

JMU received an AIP for the design

procedure for increasing design

vapor pressure SPB® tank up to

0.4 MPa (4.0 barG) from American

Bureau of Shipping in January 2017.

Diesel Engine

-Typical main engine for merchant ships

-Larger exciting force of vibration than turbine engine

Location

-Close to engine room

(3) Development of the Simplified Vibration Calculation

(3)-1 Background

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Severer environment of vibration

comparing to LNG carrier, FLNG, etc.

LNG Fuel


LNG Fuel



(3)-2 Tank Vibration Assessment -Obtaining the Natural Frequency-

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Conventional way

FEM: Time-consuming

Simplified method

Time can be saved.

Accuracy shall be verified.

𝑓 = 0.057𝜋2

𝑙2𝐸𝐼

𝜌𝐴

𝑓 =? ? ?SPB® fuel tank


(3)-3 Tank Vibration Assessment for Container Ships

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Tank height is taller than that of other types of ship


(3)-4 Rigid Body Model (Step 1) and Elastic Body Model (Step 2)

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Simplified methodFEM

Rigid + Elastic vibration

Step 1

Rigid body vibration

Step 2

Elastic body vibration

+


(3)-5 Coupling of Step 1 and Step 2 –Actual Phenomenon-

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Simplified method

1

𝑓2 ≅1

𝑓12 +

1

𝑓22

𝑓: Natural frequency of the coupling mode𝑓1: Natural frequency of Step 1 mode𝑓2: Natural frequency of Step 2 mode

FEM

Rigid + Elastic vibration


(3)-6 Verification of the Accuracy

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The Ratio of Natural Frequency (Simplified method vs FEM)

Filling level Longitudinal vibration Transverse vibration

Full 1.06 1.18

Empty 1.05 1.14

Enough accuracy for initial planning stage.

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Effect of Higher Strength compared to other cryogenic materials

Yield Stress:

3 times as that of Aluminum

Plate Thickness : 60% of Aluminum

(Stiffener size can be reduced similarly)

Comparison with Aluminum

(4) Development of High Manganese Steel

(4)-1 Creation of New Material and Welding Material

To confirm Adequate Quality and Manufacturing Cost

- Creation of New Material and Welding Material

- Basic Test for Material Property

- Confirmation of Workmanship

(4)-2 Basic Test for Material Property

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- Fatigue Strength Analysis

- Crack Propagation Analysis

- Leakage Quantities Estimation

SPB® Tank Design

・SN curve Data

・Fatigue Crack Growth Rate Curve Data

(4)-3 Confirmation of workmanship

- workability (cutting, bending etc.)

- welding

- corrosion resistance during construction

(4) Development of High Manganese Steel

Thank you for your kind attention.

More Information Available!! (Keyword: “jmu product spb”)

Homepage: http://www.jmuc.co.jp/en/products/spb_system/

Development of SPB LNG Fuel Tank for Ships. Section of Tank (2) Concept Design of SPB® LNG Fuel...

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