DISMANTLING OF ABOVEGROUND LNG STORAGE TANKS ...

DISMANTLING OF

ABOVEGROUND LNG

STORAGE TANKS

AND THEIR AGING RESEARCH

By: Hiroshi Nishigami,

Osaka Gas

2013 APR 18

17th INTERNATIONAL CONFERENCE & EXHIBITION ON

LIQUEFIED NATURAL GAS (LNG 17)

Table of Contents

1. Introduction

2. Demolition work method of the tanks

3．Aging research of the demolished tanks 3.1 Major items

3.2 Inner tank

3.3 Foundation piles

3.4 Instrumentation Devices

4. Conclusion

1. Introduction

No.2 tank

No.4 tank

No.3 tank

demolished

No.1 tank

demolished

Osaka

Kyoto

Kobe

Nara

Osaka Tokyo

Senboku terminal 1

No.1 Tank No.3 Tank

Capacity 45,000m3 45,000m3

Structure Single

containment

Single

containment

Inner tank

Material

9%Nickel

steel

Aluminum

alloy

Construction

year

1972 1972

Specification of demolished tank

Japan

Welded joint

between Inner

shell & annular

plate

Perlite powder

Thermometer,

level gauge Inner tank shell

& bottom plate

Outer tank roof

& shell plate

Outer tank

bottom plate pile Base slab

Bottom

insulation

Inner tank Visual check, Chemical

composition, Strength,

Cryogenic toughness, Fatigue

Foundation & Dike Strength, Chloride ion

content, Carbonation

depth

Outer tank Corrosion Pile Corrosion

Insulation Visual check, Thermal

conductivity, Strength

Thermometer,

level gauge

Insulation residence,

Wearing

3.1 Major items of aging research

Dike

3.2 Aging research items ~Inner tank ~

Top Shell

(8.0mm)

Bottom Shell

(20.0mm)

Sampling Part Chemical

Composition

Tensile

Test

Charpy

Impact Test

CTOD

Test

Duplex

Esso Test

Bottom Shell ○ ○ ○ ○ ○

Top Shell ○ ○ ○ - -

Annular Plate ○ - - - -

Bottom Plate - ○ - - -

Sampling Parts and Tests (Base Metal 9%Ni steel)

3.2 Results of Tensile Strength Test

9%Ni steel Base Metal

As compared with inspection certification, it is apparent

that the base metal doesn’t deteriorate with age.

Sampling

Part

Rolling

Direction

0.2% Proof

Stress [MPa]

Tensile

Stress [MPa]

Elongation

[%]

Bottom Shell L 708 761 36

C 706 762 36

Top Shell L 722 767 29

C 719 767 27

Bottom Plate L 723 776 28

C 714 769 28

Inspection

Certification - 723 779 35

Requirement - 590 690 -

3.2 Results of Tensile Strength Test

9%Ni steel Weld Joint

As compared with inspection certification, it is apparent

that the weld joint doesn’t deteriorate with age.

Sampling Part

Test after Dismantling Construction

Management Test

Tensile

Stress [MPa]

Fracture

Location

Tensile Stress

[MPa]

Bottom Shell

Vertical Weld Joint 756 Weld Metal 761

Bottom & 2nd Shell

Horizontal Weld Joint 756 Base Metal 767

Top Shell

Vertical Weld Join 781 Base Metal 788

Requirement 655

(at 20 deg C) - -

3.2 Results of Charpy Impact Test

As compared with inspection certification, it is apparent

that the base metal doesn’t deteriorate with age.

9%Ni steel Base Metal

Bottom Shell

Top Shell (Half size)

Inspection Certification (Bottom shell)

Requirement

Ch

arp

y A

bso

rbe

d E

ne

rgy (

J)

100

80

60

40

20

0

Rolling Direction L C

3.2 Results of Charpy Impact Test

As compared with inspection certification, it is apparent

that the weld joint doesn’t deteriorate with age.

9%Ni steel Weld Joint

Charp

y A

bsorb

ed E

nerg

y (

J)

Notch Location

WM FL FL+1mm FL+3mm FL+5mm

Bottom Shell V

Bottom & 2nd Shell H

Top Shell V (Half size)

Inspection Certification (Bottom shell)

Requirement

Corrosion measurement on actual piles in order to

grasp actual corrosion condition.

Specification of tank foundation

Diameter of base slab

48.0m

From pile head to 6m below

Whole length

Framing plan of piles

Pile head

Pile toe

Joint

Measure points

Steel pipe pile

Length: 25.0m

Outer diameter: 406.4mm

Thickness: (Upper part) 12.7mm

(Lower part) 9.5mm

Number: 496

3.3 Corrosion survey of foundation piles

-25

-20

-15

-10

-5

0

0.0 0.5 1.0 1.5 2.0 2.5 3.0

Corrosion loss : up to 0.6mm

less than the 2.0mm as the corrosion margin.

Corrosion rate : up to 0.014mm/year Depth

(m)

Corrosion

allowance

Corrosion loss (mm)

Test results regarding corrosion content

3.3 Test results of corrosion survey

Groundwater level:

GL -2m

(Cut into each 1 m)

3.4 Deterioration of Instrumentation Devices Thermometer for Roll-over detection

<Model>

Metal-sheathed resistance

thermometer sensor

(3-wire type, Platinum resistor)

<Sheath length>

13m～41m (at intervals of 2m)

<Classification>

0.5

<Sheath material>

SUS316

<Sheath outer diameter>

φ4.8mm

Thermometer

No.

Insulation resistance

[MΩ]

Region of insulation

degradation [m] (distance from the head)

No.1 tank

1 1 1

3 6 1

5 2 1

12 11 1

No.3 tank 1 0.1 1

3.4 Insulation resistance test

Insulation

resistance

The degradation occurred within 1m from the

thermometer’s head.

4. Conclusion

>It was proved that our demolition work method is

safe and does not affect on the other city gas

production plants in surrounding area.

>The mechanical properties of the inner tank’s

material satisfied sufficient levels. The other

results (thermal insulation material, steel pipe and

instrumentation devices) also showed no

significant deterioration.

>The results also proved the high integrity of the

LNG storage tanks at that time.

Thank you for your attention!! Thank you for your attention!!

Fin

Contact E-mail address

[email protected]