ALTERNATIVE SPIRAL WOUND GASKET FILLER ......ALTERNATIVE SPIRAL WOUND GASKET FILLER MATERIAL TO REDUCE FLANGE FACE CORROSION Paul Welsford AMIMechE, Flexitallic Ltd OGA 2017 –Subsea

ALTERNATIVE SPIRAL WOUND GASKET FILLER MATERIAL TO REDUCE FLANGE FACE CORROSION

Paul Welsford AMIMechE, Flexitallic LtdOGA 2017 – Subsea UK

PREVENTING FLANGE FACE CORROSION

>300 PLATFORMS

>8,000KM OF PIPELINES

> 1 MILLION GASKETED

FLANGE CONNECTIONS


“Every flange connection in a plant is an essential built-in weakness that allows

the overall plant to be stronger in the long-term by giving it the power to be

maintained safely and upgraded with relative ease.

All it takes is one of these weak links to not be strong enough for the whole

system to fall apart.”

- Some Smart Pipeline Engineer


CONTENT

• Corrosion – the hidden enemyCorrosion: challenges & mechanisms

• Current products on the marketWhere are we at?

• The New Solution

• Testing

• Summary


Bolted flange joints can be vulnerable to

gasket degradation and

flange face corrosion


CORROSION – challenges & mechanisms

Detection Waste HSEShutdown

(Unscheduled)Cost


Traditional Sealing Materials

• Graphite is widely used for spiral wound gaskets. An electrical conductor and highly “noble” so promotes corrosion.

• Mica is sometimes chosen in place of graphite however it exhibits very poor sealingcharacteristics.

• PTFE is not fire safe. Associated with increasing crevice corrosion in certain applications.


GALVANIC SERIES OF METALS IN SEAWATER

• Seawater is an electrolyte with well known

effects on different materials

• Graphite is the most noble, causing corrosion

of common stainless steels

• Relative position in the table, distance apart,

contact area, temperature, flow rate all affect

corrosion


CORROSION – challenges & mechanisms

1. Flange and gasket material remain important criteria

to avoid corrosion

2. Choosing the right gasket can have significant

impact on galvanic corrosion prevention

3. The selection of traditional gasket materials leads to problems


Market need for new materials

and corrosion resistance

combining optimum sealing properties


New Material (CORRICULITE) Development

• Formulation optimised for corrosion applications

• Inert, non-conductive filler material prevents the onset of galvanic

corrosion

• Improved sealing performance compared to graphite-filled spiral

wound gaskets

• Fire safe to API 6FB


Evaluates gasket

materials

resistance to

seawater induced

corrosion

Evaluates gasket

sealing capacity

under “real world”

conditions in a

flanged connection

Measures leakage

rates against a

gasket stress with

internal pressure at

different

temperatures

AMTEC

sealing test

PRODUCT PERFORMANCE VALIDATION

Corrosion

testing

Submerged

testing

Records the

electrochemical

potential of sealing

materials

Electrochemical

evaluation


1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

1.00E+01

1.00E+02

0 20 40 60 80 100 120 140 160 180

Leak

rat

e [m

g/m

/s]

Gasket stress [MPa]

Graphite Corriculite Mica

AMTEC SEALING TEST

• A flatter line in better as it indicates resilience to unloading in service

• New Material significantly tighter than both graphite and mica

x500

x100,000


CORROSION TESTING

PTFE Isolator

PTFE Isolator

PTFE Isolator

PTFE Isolator

PTFE Isolator

THERMICULITE

NEW MATERIAL

NEW MATERIAL

GRAPHITE

Control sample

No visible corrosion

No visible corrosion

Corrosion due to presence of graphite


ELECTROCHEMICAL EVALUATION

• The graphite gasket initiates corrosion at a level around half that of the New Material sample.

0

50

100

150

200

250

300

-5

0

5

10

15

20

25

30

35

Vo

ltag

e (m

V A

g/A

gCl)

Time

Co

rro

sio

n P

ote

nti

al (

mA

)

Corriculite Current (mA) Graphite Current (mA) Voltage Step (mV)


SUBMERGED TESTING

• https://vimeo.com/210782491

• VIDEO

https://vimeo.com/210782491


SUBMERGED TESTING

• Flange assemblies submerged in seawater and pressurized with Nitrogen.

• New Material (4%)

• Graphite (17%)

• Mica (20% in 1 hr)460

480

500

520

540

560

580

600

620

0 25 50 75 100 125 150 175 200 225 250 275 300 325 350P

ress

ure

(p

si)

Time (Hours)

Corriculite Graphite Mica


FIRE SAFETY – API 6FB

• Pass achieved

• Zero leak rate measured


SUMMARY

• Addresses shortcomings of current materials on

the market.

• Extends equipment life by preventing corrosion

• Eliminates safety & environmental risks

• Reduces downtime & production losses

• Reduces costs associated with maintenance

• Maintains seal integrity even in an external fire

situation

www.corriculite.com


THANK YOU

ANY QUESTIONS?

www.Corriculite.com

[email protected]

http://www.corriculite.com/

Documents

ALTERNATIVE SPIRAL WOUND GASKET FILLER ......ALTERNATIVE SPIRAL WOUND GASKET FILLER MATERIAL TO REDUCE FLANGE FACE CORROSION Paul Welsford AMIMechE, Flexitallic Ltd OGA 2017 –Subsea