RILSAN Polyamide 11 in Oil & Gas Off-shore Fluids ... · RILSAN® Polyamide 11 in Oil & Gas Off-shore Fluids Compatibility Guide ATOFINA Chemicals, Inc. 2000 Market Street Philadelphia,

RILSAN® Polyamide 11

in Oil & Gas

Off-shore Fluids

Compatibility Guide

ATOFINA Chemicals, Inc. 2000 Market Street Philadelphia, PA 19103-3222 Telephone: (215) 419-7000

ATOFINA Canada, Ltd. 700 Third Line Oakville, Ontario L6J5A3 Canada, Telephone: (905) 827-9841

www.AtofinaChemicals.com

After 14 years of research in a program

launched in 1958 by the French Institut de

Petrole, polyamide 11 was chosen as the

best material out of several hundred

tested. Today RILSAN® polyamide 11, the

unique polyamide from ATOFINA, looks

back at a service history of over 30 years

in the petroleum industry. The combined

qualities of flexibility, excellent impact

resistance even at low temperatures, high

resistance to aging and good compatibility

with products common to the petroleum

industry environment have made RILSAN

polyamide 11 an unequaled standard.

For even higher demands, especially at

higher temperatures or when the

combined high temperature and high

water content requirements are too

severe, ATOFINA proposes its unique

KYNAR® off-shore grade. KYNAR is a

thermoplastic fluoropolymer resin

developed by ATOFINA. Outstanding

thermomechanical properties combined

with exceptional chemical and aging

resistance enable KYNAR to meet the

most stringent demands.

The data given in this brochure describe the material performance of RILSAN® polyamide 11 in applications such aspneumatic or hydraulic tubes. For large diameter pipes or sheaths such as in flexible pipe the data give indicationsof lifetime limits, but further considerations might have to be taken into account. Hence this data may be inapplica-ble where lifetime and design specifications established by flexible pipe manufacturers or joint industry efforts haveresulted in new recommended practices or industry specifications.

The statements, technical information and recommendations contained herein are believed to be accurate as of the date hereof. As the condition and methods of use of

the products and of the information referred to herein are beyond our control, ATOFINA expressly disclaims any and all liability as to any results obtained or arising from

any use of the product or reliance on such information; NO WARRANTY OF FITNESS FOR ANY PARTICULAR PURPOSE, WARRANTY OF MERCHANTABILITY, OR ANY OTHER WAR-

RANTY, EXPRESS OR IMPLIED, IS MADE CONCERNING THE GOODS DESCRIBED OR THE INFORMATION PROVIDED HEREIN. The information provided herein relates only to the

specific product designated and may not be applicable when such product is used in combination with other materials or in any process. The user should thoroughly test

any application before commercialization. Nothing contained herein should be taken as an inducement to infringe any patent and the user is advised to take appropriate

steps to be assured that any proposed use of the product will not result in patent infringement.

BEFORE HANDLING THIS MATERIAL, READ AND UNDERSTAND THE MSDS (MATERIAL SAFETY DATA SHEET) FOR ADDITIONAL INFORMATION ON PERSONAL PROTECTIVE EQUIP-

MENT AND FOR SAFETY, HEALTH AND ENVIRONMENTAL INFORMATION.

1 General introduction and material overview Page 2

1.1 Introduction to thermoplastic polymers 3

1.2 General guide for the use of polyamide 11 3

2 Technical data: RILSAN® BESNO P40 TLO resin 5

2.1 Mechanical properties and design parameters 5

2.2 Thermal properties 5

3 Overview of aging properties and chemical compatibility 7

3.1 Heat aging 7

3.2 UV aging 8

3.3 Chemical aging 9

3.4 Chemical resistance tables – RILSAN® BESNO P40 resin grades 10

3.5 Aging in water and acidic solutions – hydrolysis 15

3.6 Influence of methanol on aging and mechanical

properties, permeability data 17

3.7 Influence of monoethyleneglycol and ethyleneglycol

based hydraulic liquids on mechanical properties 19

3.8 Compatibility of RILSAN® BESNO P40 TLX and BESNO P40 TLO

resins with various offshore fluids and chemicals 21

3.8.1 Demulsifiers 22

3.8.2 Corrosion inhibitors – oil soluble 22

3.8.3 Corrosion inhibitors – water soluble 23

3.8.4 Corrosion inhibitors – oil soluble and water dispersible 24

3.8.5 Oxygen scavengers 24

3.8.6 Biocides 25

3.8.7 Paraffin inhibitors 26

3.8.8 Scale inhibitors 27

3.8.9 Overview of chemical compatibility of RILSAN® BESNO P40 TLX

and BESNO P40 TLO resins with common offshore chemicals 27

3.9 Compatibility with crude oil, natural gas,

carbon dioxide (CO2) and hydrogen sulfide (H2S) 29

3.9.1 Compatibility with crude oil 29

3.9.2 Compatibility with natural gas 29

3.9.3 Compatibility with carbon dioxide (CO2) 30

3.9.4 Compatibility with hydrogen sulfide (H2S) 30

3.10 Data on permeability of polyamide 11 30

3.11 Blistering resistance 31

1

2

3

CONTENTSPA11

General introduction and

material overview

The term umbilical is applied to

connective systems between underwater

equipment such as wellheads, subsea

manifolds or remote operated vehicles

(ROVs).

An umbilical generally consists of a group

of hydraulic lines, injection lines and/or

electrical cables bundled together in a

flexible arrangement, sheathed and

sometimes armored for mechanical

strength and/or a specific buoyancy.

Related information describing

recommended practice can be found in

the API documents 17R, but also in

API 17B and API 17J on flexible pipes.

Specific examples of structures are given

below.

A range of materials comes into play to

make up the entire structure:

• carbon steel for the armor

• metals for electrical wire

• cable sheathing

• different thermoplastics for the

injection and hydraulic lines

• fiber reinforcement, often aramid

fibers are used

• outer sheathing of umbilical, often

polyethylene or polyurethane

• duplex steel for hydraulic lines

Extruded pipe made from polyamide 11,

in combination with an aramid braiding

and subsequently sheathed with another

layer of polyamide, provides a very

reliable hose possessing high flexibility,

very high pressure performance, unlimit-

ed seamless tube length and long life in

harsh offshore environments.

1

1

2

Tape binder

Power cablesPA11 hydraulic

hose 1/2”

PA11 hydraulic

hose 1/2”

PA11 hydraulic

hose 1”

PP fillers PP fillers

Outer sheath

PE sheath

PP separator

and outer sheathSteel armor wires Steel armor wires

Fig.1 Umbilical cross sections

1.1 Introduction to thermoplastic

polymers

Thermoplastic polymers are a class of

materials with a wide range of flexibility,

a medium range of elasticity and a wide

range of upper temperature limits. For

semicrystalline materials, their maximum

use temperatures are limited by the

melting point of the crystalline phase.

An image of the general structure of a

semicrystalline thermoplastic material is

given above. The properties of such a

material are governed by the interplay of

the crystalline phase giving strength and

temperature resistance and the amor-

phous phase rendering the material

tough and flexible. Typical examples of

semicrystalline polymers are high density

polyethylene (HDPE), polyamide 11 or

nylon 11 (PA11) and polyvinylidene

fluoride (PVDF).

The following table gives an outline of the scope of properties of thermoplastic

polymers which can be found in offshore applications today.

COMPARISON OF DIFFERENT THERMOPLASTIC POLYMERS USED IN OFFSHORE SERVICE

PVC HDPE PA11 PVDF

Density (g cm-3) 1.38 – 1.40 0.95 – 0.98 1.03 1.78

Melting Point (°C) 80 130 – 135 188 160 – 170

Flexural modulus (MPa) 1100 – 2700 700 – 1000 300 – 1300 800 – 2000

Tensile strength (MPa) 50 – 75 20 – 30 25 – 30 37 – 48

Shore D hardness 55 – 70 32 – 61 75 – 77

LOI (%) 42 5.7 26 44

1.2 General guide for the use of polyamide 11

Polyamide 11 is a specialty nylon. It combines high ductility, excellent aging resistance

and high barrier properties with mechanical strength and resistance to creep and fatigue.

It thus compares advantageously to standard nylons such as 6 and 66. Notably its signifi-

cantly lower water absorption results in better aging resistance, higher chemical resist-

ance and less property fluctuation due to plasticization by water.

COMPARISON OF DIFFERENT POLYAMIDES

PA 66 PA 6 PA 11 PA 11 plasticized

Melting point (°C) 255 215 188 184

Density 1.14 1.13 1.03 1.05

Flexural modulus (MPa)

50% RH (23°C) 2800 (1200) 2200 1300 300

Water absorption

50% RH (23°C) 2.5 2.7 1.1 1.2

in water immersion 8.5 9.5 1.9 1.9

Charpy notched impact

ISO 180/1A (kJ/m2)

23°C 5.3 (24) 8 (30) 23 N.B.

- 40°C X X 13 7

ISO 527

Tensile stress (MPa) 87 (77) 85 (70) 36 21

Tensile elongation (%) 5 (25) 22 –

Elongation at rupture (%) 60 (300) 15 – 200 360 380

N.B. = no break, values in parentheses at elevated humidities, RH = relative humidity

a. repeat unit cell b. crystalline (lc) and amorphous(la) domains within the long period Lp (lamellar structure) c. a stack of lamelle d. the spherolite.

3

●

●●

●

●

●

●●

●

●●

●

●

●

●

●

●

●

●

●

a. b.

Lp

lc

la

c.d.

Fig. 2 Morphology of a semicrystalline polymer

The excellent properties of polyamides

and in particular polyamide 11 are a result

of the amide linkages in the chain which

allow a strong interaction between the

chains by hydrogen bonds. Low creep,

high abrasion resistance, good resistance

to fatigue and high barrier properties are

a direct result of these strong inter-chain

links.

Molecules which can create hydrogen

bonds such as water, methanol, ethanol,

ethylene glycol can penetrate polyamide

11 and lead to plasticization. They can

interfere in inter-chain hydrogen bonds

thus weakening the hydrogen bond net-

work. Especially methanol has a signifi-

cant absorption rate and must be consid-

ered in certain applications. Please refer

to section 3.6.

Although polyamide 11 is highly resistant

to aging and chain breakdown, the reac-

tion of water with amide bonds creates a

limit to the use of polyamide at higher

temperatures and in the presence of

water. The specific reaction induced by

water, called hydrolysis, can be accelerat-

ed in the presence of acids. At continuous

service temperatures of 65°C and below,

the impact of hydrolysis on polyamide 11

in a neutral medium such as water can be

neglected. Under these conditions, the

material can have a service life of 20 years

or more. The use at higher continuous

service temperatures depends on the per-

formance requirements and more precise

conditions. The reader should refer to

data on temperature – lifetime correla-

tions in section 3.5.

A special molecule, butyl-benzene-sulfon-

amide or BBSA, has been chosen as a

plasticizer. It has very low volatility and

leads to an efficient plastification of the

resin. Questions related to its extraction

or its influence on material properties are

discussed in section 3.7.

A range of RILSAN® polyamide 11 grades

has been developed to correspond to the

specific needs of the oil and gas industry.

BESNO P40 TL

A high viscosity and plasticized grade

developed for pipe extrusion.

BESNO P40 TLX


developed for pipe extrusion especially

for the inner pressure layer of flexible

pipe.

BESNO P40 TLO


developed for pipe extrusion with a low

extractable content especially adapted for

hydraulic hoses in umbilicals.

The blooming of oligomers has clogged

valves or filters in subsea installations.

Oligomeric molecules present in the

polymerized PA11 resin are extracted and

the material is compounded with a

plasticizer and heat additives.

BESNO P20 TL

A medium plasticized, high viscosity extru-

sion grade for pipe and sheath extrusion.

BESNO TL

A high viscosity unplasticized grade

adapted for pipe extrusion.

BMNO TLD

An injection molding grade.

These grades are all of natural color.

Certain colored grades or color master

batches are also available.OIISIIO

N

H

H–NC=O

O=CO=C

H–N

O=CN–H

H–NC=O H–N

N–H

IIIIIII O=CN–H IIIIIII O=C

C=O IIIIIII H-NC=O IIIIIII H–N

C=O

H–N

C=O

N–H IIIIIII O=C

IIIIIII

IIIIIII

IIIIIII

4

PA CHAINS WITH H-BONDING

BUTYL-BENZENE-SULFONAMIDE OR BBSA

REACTION: HYDROLYSIS

vvvvvC–Nvvvvv +H2O vvvvv CO2H + vvvvv NH2→←

=–

O

H

FLEXURAL TESTS ACCORDING TO ISO 178 : 93

Temperature °C -40 -20 23 80

Flexural modulus MPa 1950 1350 320 165

(dry material)

Flexural modulus MPa 2050 1150 280 160

(after conditioning 15

days at 23°C, 50% R.H.)

FLEXURAL TESTS ACCORDING TO ASTM D790

Temperature °C 23 80

Flexural modulus MPa 330 170

(dry material)

IMPACT TESTS ACCORDING TO ISO 179 (type 1)

Temperature °C -40 23

Unnotched KJ.m-2 N.B. N.B.

Notched KJ.m-2 8 N.B.

N.B. = no break

IMPACT TESTS ACCORDING TO ISO 179 :93 CA

Temperature °C -40 -20 0 23

Notched KJ.m-2 6.8 9.9 52.9 N.B.

2.2 Thermal properties

THERMAL CONDUCTIVITY

Temperature (°C) 39 61 82 102 122 142 163 182 202 223

K (W/m°K) 0.21 0.24 0.24 0.24 0.24 0.24 0.25 0.25 0.25 0.25

Technical data: BESNO P40 TLO

BESNO P40 TLO is a plasticized and

washed polyamide 11 grade. The

methanol washing process eliminates

low molecular weight extractables

(chemical name: oligomers) which can

lead to fouling or clogging of the filters

or needle valves.

2.1 Mechanical properties and

design parameters

DENSITY

ASTM D792 1.05 g/cm3

HARDNESS

ISO 2039/2 (R SCALE) 75

ISO 868 (D SCALE) 61

COMPRESSION STRENGTH

ASTM D695 (23°C) 50 MPa

ABRASION RESISTANCE

ISO 9352 : 1995(F)(loss in weight after 1000 rev under500g H18 wheel) 22 mg

THERMAL EXPANSION HEAT DISTORTION TEMPERATURE SOFTENING POINT

ASTM E 821 ASTM D648 ASTM D1525

from -30°C to +50°C 11x10-5 °K-1 ISO 75 (0.46 Mpa) 130 °C under 1 daN 170 °C

from +50°C to +120°C 23x10-5 °K-1 ISO 75 (1.85 Mpa) 45 °C under 5 daN 140 °C

2

5

HEAT CAPACITY

Measured by D.S.C.

Temperature (°C) 20 50 80 120 160 200 230 260

cal/g.°C 0.40 0.50 0.6 0.6 0.65 0.65 0.65 0.65

GLASS TRANSITION TEMPERATURE

D.M.A. 0-10 °C

TEMPERATURE ( °C)

ST

OR

AG

E M

OD

ULU

S E

' (P

a)

LO

SS

MO

DU

LUS

E"

(P

a)

-140 -120 -100 - 80 -60 -40 -20 0 20 40 60 80 100 120 140 160 180

1.00E+10

1.00E+09

1.00E+08

1.00E+07

E'

E"

Fig. 3 BESNO P40 TL – plasticized PA11 Measurement in a 3-point bending flexural mode at 10 rad/s

DYNAMIC MECHANICAL ANALYSIS

(full curve)

The DMA curve obtained is characteristic

for semicrystalline polymers. Essentially

four different temperature zones can be

described which are related to character-

istic relaxational transitions.

The first zone is a low temperature high

modulus zone which starts to soften

around –20°C. Due to efficient low tem-

perature relaxations (centered around

–80°C) PA11 is tough even at these very

low temperatures.

Between –20 and 40°C the material soft-

ens gradually to attain its characteristic

flexibility. This softening is due to the

onset of motion, the glass transition, in

the amorphous regions. From 40 to 160°C,

the PA11 modulus remains very stable

due to the crystalline phase with its

onset of melting starting only around

160°C. The fine distribution of the crys-

talline phase and its constant modulus,

largely independent of temperature,

guarantee very stable mechanical

properties over a very wide temperature

range and a high resistance to creep.

For a textbook on the comprehensive

analysis of DMA data refer to Anelasticand Dielectric Effects in Polymer Solids by

N.G. McCrum, B.E. Read, G. Williams;

Dover Publication, New York, 1991.

6

Overview of aging properties of

polyamide 11

Polyamide 11 is subject to aging phe-

nomena. These phenomena are rather

varied and depend on the specific envi-

ronment. The most important factors

inducing aging and subsequent loss of

properties for polyamides are:

• Heat

• UV light

• Chemicals

All data given in the following chapters

refer to BESNO grades. The suffix “P40”

signifies a plasticized grade.

“TL” and “TLX” signify various heat and

light stabilizer packages.

The suffix “TLO” signifies an oligomer

extracted grade which is heat and light

stabilized.

500

450

400

350

300

250

200

150

100

50

100 150 200 250 300 3500

TIME (HOURS)

ELO

NG

AT

ION

AT

BR

EA

K (

%)

50

•

•

•

•

••

•

mean values•

Fig. 4 Reduction of elongation at break: BESNO P40 TLX aged at 155°C

3.1 Heat aging

Heat in the presence of oxygen causes oxidative degradation. For the reaction of

oxygen with an organic polymer to take place, oxygen molecules must diffuse into the

bulk polymer from the outside. Reactions occur first on the surface, leading to surface

embrittlement.

Oxidative degradation can be efficiently suppressed by anti-oxidants. All RILSAN® PA11

grades used in offshore applications have specially suited anti-oxidant packages. In

the grade nomenclature, this is notified by a suffix “TL.”

Heat aging performance has been established based on accelerated tests in a ventilat-

ed oven. In most cases the performance is monitored by tensile experiments. An

example of a typical test series is given in the figure below.3

7

3.2. UV aging

UV light in conjunction with oxygen leads

to similar surface degradation effects as

heat degradation. Effective anti-UV light

stabilizing packages are routinely

employed to protect the resin (marked by

suffix “TL”). Different tests have been

developed to simulate the impact of UV-

light combined with natural weathering.

These tests include cycles where the sam-

ples are alternatively subject to moist heat

and UV light.

The UV resistance is measured under

accelerated conditions on a standardized

machine, XENOTEST 1200, according to

the RENAULT standard no. 1380. Results

are shown in Figure 6.

Conditions:

Xenon lamps with filters eliminating radia-

tion with wave lengths less than to 300 nm.

Intermittent exposure – equal periods of

light and darkness.

During a 20 minute cycle, the specimens

are exposed to 3 minutes of distilled

water spray and 17 minutes of exposure

without spraying. The relative humidity of

the cabinet during period without spray is

approximately 65%.

Black panel temperature in the measure-

ment cabinet:

65°C ± 2°C before spraying

45°C ± 2°C after spraying

The specimens are dumbells according to

ISO/NFT 51034 cut from a film of 1 mm

thickness. Tensile tests are carried out at

50 mm/minute.

TEMPERATURE ( °C)

LOG

TIM

E (

DA

YS

)

150 140 130 120 110 100 90 80

4

3.5

3

2.5

2

1.5

1

.5

0

■■■ 1 YEAR ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 5 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 10 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 20 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

+++ + + + + +

Machined

Injected

Linear (machined)

Linear (injected)

+

400

350

300

250

200

150

100

50

500 1000 1500 2000 25000

•

•

•

TIME (HOURS)

ELO

NG

AT

ION

AT

BR

EA

K (

%)

•

•

Fig. 5 Laboratory aging as a function of temperature – half times from elongation at break

are taken from injection-molded and machined samples – material is BESNO P40 TLX. The

influence of poorer surface quality on aging performance is demonstrated.

Fig. 6 Laboratory aging of BESNO P40 TLX: Xenotest 1200

TIME (h) 0 500 1000 1400 2000

EB (%) 380 330 275 85 33

EB/EB0 1 0.87 0.72 0.22 0.09

MB (MPa) 72 61 47 34 25

YI 6 14 16 13 13

EB = elongation at break, MB = modulus at break, YI = yellowness index

8

3.3 Chemical aging

In offshore applications, certain offshore

fluids and chemicals can have a detrimental

effect on polyamide 11 performance. For

each application, the specific chemicals

should be reviewed in order to estimate

service life.

Polyamides, and in particular polyamide

11, are very resistant to many types of

chemicals. Polyamide 11 is very resistant

to oils and hydrocarbons as well as to a

large variety of solvents. In contrast to

standard polyamides 6 and 66; polyamide

11 shows only little absorption of water

and is also resistant to diluted acids and

bases. Due to its increased flexibility and

molecular structure, it is also highly resistant

to stress cracking, unlike most other thermo-

plastics.

Polyamide 11 can be used in conjunction

with a great variety of standard offshore

chemicals. A detailed description of compat-

ibilities is given in sections 3.8 and 3.9.

Because chemical species attack thermo-

plastic resins when they are absorbed,

diffusion and solubility play important roles

in the assessment of chemical compatibility.

There are two effects induced by absorbed

species – an influence on the mechanical

properties due to plasticization, and a

chemical effect leading to loss of material

performance.

Specific examples of absorption and

plasticizer extraction are given in sections

3.6 and 3.7 on methanol-and glycol-based

hydraulic liquids.

The main chemical effect is reduction in

polymer molecular weight due to hydroly-

sis. Hydrolysis is the reverse reaction of the

chain-forming polycondensation reaction.

It can be induced by water at elevated

temperatures and is accelerated by acids

and, to some extent, also by bases. Due to

the importance of hydrolysis in aging relat-

ed to offshore applications, section 3.5

describes the phenomenon in detail.

Fig. 6A Evolution of Yellowness Index (YI) in Xenotest aging

EQUILIBRIUM SWELLING AND CHEMICAL COMPATIBILITY

OF COMMON SOLVENTS AND OFF SHORE FLUIDS

Solvent Swelling at 20°C in % weight Compatibility

Benzene 7.5 good up to 70°C / swelling

Toluene 7 good up to 90°C / swelling

Cyclohexane 1 good

Petrol ether 1.5 good

Decaline < 1 good

Gasoline depends on type, mostly < 2% good

Kerosene depends on type, mostly < 2% good

Ethylene glycol 2.5 good up to 60°C / swelling

Glycerol 1 good up to 60°C

9

40

35

30

25

YI 20

15

10

5

500 1000 1500 2000 25000

••

•

TIME (HOURS)

ELO

NG

AT

ION

AT

BR

EA

K (

%)

•

•

3.4. Chemical resistance table – BESNO P40 grades

The following tables give a first impression of chemical

resistance of PA11 extrusion resins.

G: good

L: limited (important swelling or dissolution)

P: poor

Index * denotes swelling, index b denotes discoloration

(brownish or yellowish)

Concentration 20°C 40°C 60°C 90°C

Inorganic Salts

calcium arsenate Concentrated or paste G G G

sodium carbonate Concentrated or paste G G L P

barium chloride Concentrated or paste G G G G

potassium nitrate Concentrated or paste Gb Lb P P

diammonium phosphate Concentrated or paste G G L

trisodium phosphate Concentrated or paste G G G G

aluminium sulphate Concentrated or paste G G G G

ammonium sulphate Concentrated or paste G G L

copper sulphate Concentrated or paste G G G G

potassium sulphate Concentrated or paste G G G G

sodium sulphide Concentrated or paste G G L

calcium chloride Concentrated or paste G G G G

magnesium chloride 50% G G G G

sodium chloride saturated G G G G

zinc chloride saturated G G L P

iron trichloride saturated G G G

barium formate saturated G L P

sodium acetate saturated G L P

10


Other Inorganic Materials

water See section 3.5 G G G G

sea water G G G G

carbonated water G G G G

bleach L P P P

hydrogen peroxide 20% G L

oxygen G G L P

hydrogen G G G G

ozone L P P P

sulphur G G

mercury G G G G

fluorine P P P P

chlorine P P P P

bromine P P

potassium permanganate 5% P P

agricultural sprays G G

Organic Bases

aniline Pure L P P P

pyridine Pure L P P P

urea G G L L

diethanolamine 20% G G* G* L

Inorganic Bases

sodium hydroxide 50% G L P P

potassium hydroxide 50% G L P P

ammonium hydroxide concentrated G G G G

ammonia liquid or gas G G

11


Inorganic Acids

hydrochloric acid 1% G L P P

10% G L P P

sulphuric acid 1% G L L P

10% G L P P

phosphoric acid 50% G L P P

nitric acid P P P P

chromic acid 10% P P P P

sulphur dioxide L P P P

Halogenated solvents

methyl bromide G P

methyl chloride G P

trichloroethylene L P

perchloroethylene L P

carbon tetrachloride P

trichloroethane L P

Freon G

Phenols P P P P

Esters and Ethers

methyl acetate G G G

ethyl acetate G G G

butyl acetate G G G L

amyl acetate G G G L

tributylphosphate G G G L

dioctylphosphate G G G L

dioctylphthalate G G G L

diethyl ether G

fatty acid esters G G G G

methyl sulphate G L

12


Various Organic Compounds

anethole G

ethylene chlorohydrin P P L

ethylene oxide G G P P

carbon disulphide G L L

furfuryl alcohol G G

tetraethyl lead G

diacetone alcohol G G L P

glucose G G G G

Organic Acids and Anhydrides

acetic acid L P P P

acetic anhydride L P P P

citric acid G G L P

formic acid P P P P

lactic acid G G G L

oleic acid G G G L

oxalic acid G G L P

picric acid L P P P

stearic acid G G G L

tartaric acid G G G L

uric acid G G G L

refer to section 3.5 – role of acidity in hydrolysis

13


Hydrocarbons

methane G G G G

propane G G G G

butane G G G G

acetylene G G G G

benzene G G L P

toluene G G L L

xylene G G L L

styrene G G

cyclohexane G G G L

naphthalene G G G L

decalin G G G L

crude oil G G G L

Alcohols

methanol Pure G L P

ethanol Pure G L P

butanol G L P

glycerine pure G G L P

glycol G G L P

benzyl alcohol L P P P

Aldehydes and Ketones

acetone Pure G G L P

acetaldehyde G L P

formaldehyde G L P

cyclohexanone G L P

methylethylketone G G L P

methylisobutylketone G G L P

benzaldehyde G L P

14

3.5 Aging in water and acid solutions – hydrolysis

In many offshore conditions, the performance loss for polyamide 11 has been linked to

a chain scission mechanism due to a reaction with water. Polyesters, polyamides and

polyurethanes are created by polycondensation. The polycondensation reaction creating

the long chains is reversible and the opposite reaction is called hydrolysis. Among the

cited polymers, polyamide 11 is particularly resistant to hydrolysis due to its low

moisture absorption (~2% water at saturation).

The hydrolysis chain scission reaction is not significant in ordinary use at ambient tem-

peratures. Polycondensates are formed at temperatures between 200 and 350°C. The

reverse reaction rate at, or slightly above, room temperature is insignificant. Only the

use of PA11 continuously over many years at a maximum temperature of 65°C or higher

makes hydrolysis a prevailing degradation mechanism.

In oilfield use, PA11 is rarely exposed to pure water but rather to oil/water mixtures. It

has been shown that the hydrolysis mechanism operates in exactly the same way

whether only water is present or a water phase is present alongside an oil phase.

150

140

130

120

110

100

90

80

70

60

100 1000 10000 100000

AGING TIME (DAYS)

AG

ING

TE

MP

ER

AT

UR

E (

°C)

100

----

----

----

----

----

----

----

----

----

----

----

--

----

----

----

----

----

----

----

----

----

----

----

--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

---

----

----

----

----

----

---

1 year

5 years

10 years

20 years

1 month

Fig. 7 Lifetime estimation of PA11 in water contact with pure water (pH 7) as a function of temperature

polycondensation => <= hydrolysis

vvvvv CO2H + vvvvv NH2 vvvvvC– N vvvvv +H2O→←

=–

O

H

15

An aggravating factor for the hydrolysis

process is the presence of acids – either

carbonic acid produced under CO2 pres-

sure or naphthenic acids possibly present

in crude oil.

Carbonic acid formed by the dissolution

of carbon dioxide in water under pressure

causes a more severe polymer perform-

ance loss than gaseous carbon dioxide.

In the case of naphthenic acids, the larger

molecule size slows its diffusion into the

polymer. In this case, a distinct surface

attack or a gradient over the sample thick-

ness can be observed.

TEMPERATURE ( °C)

■■■ 1 YEAR ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 5 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 10 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 20 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

LIF

ET

IME

(D

AY

S)

140 130 120 110 100 90 80 70

100000

10000

1000

100

10

1

•

•

•

•■

■

▲

▲

■

■

■

■

■

■

▲

▲

■

■

•

pure water pH=7

pH=5 CO2 liquid

pH=4 CO2 gas

pH=4 CO2 liquid

▲■

TEMPERATURE ( °C)

■■■ 1 YEAR ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 5 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 10 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 20 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

LIF

ET

IME

(D

AY

S)

140 130 120 110 100 90 80 70

100000

10000

1000

100

10

1

•

•

•

•■

■

■

■

■

■

•pure water pH=7

pH=4 CO2 liquid

Strong organic acid

■

◆

◆

◆

◆

■

16

Fig. 8 Hydrolysis resistance as a function of pH

Fig. 9 Aging behavior as a function of pH

3.6 Influence of methanol on aging and mechanical

properties, permeability data

Methanol is a widely used injection fluid. For example, it is effi-

cient in dissolving gas hydrates formed during a gas production

pipe shut-down. Methanol, due to its small molecule size and its

high solubility, has a high permeation rate through PA11. It is

also an efficient solvent for plasticizer extraction. In spite of

these unfavorable factors, methanol can be successfully used in

conjunction with PA11 hydraulic tubes.

Methanol affects the material performance of PA11 in

several ways:

• A swelling effect accompanied by plasticization. At temperatures

of 140°C and above, methanol becomes a solvent for PA11.

• Plasticizer extraction.

• A methanolysis reaction which leads to a loss of

polymer molecular weight.

The effect of methanol absorption on mechanical properties is

outlined in the figure below.

A rapid drop in strength as measured by stress at rupture is

observed due to deplasticization. The resin strength then equili-

brates in methanol leading to stable properties.

Extraction of plasticizer and swelling due to methanol change

the modulus, but this is not an aging effect. Once the modulus

after methanol conditioning is attained, it remains stable. The

long-term stability of polyamide 11 in methanol is further

demonstrated in experiments outlined below.

Long term aging data of PA11, BESNO P40 TLO in methanol

Small dogbone samples are immersed at a given temperature in

methanol in an autoclave. After a given time, five samples are

retrieved and tensile tests are performed.

DATA AT 40°C

Time (days) Stress at rupture (MPa) Elongation at rupture (%)

0 53 ± 0.86 438 ± 13

40 42.2 ± 2.63 597 ± 34

100 42.9 ± 0.9 646 ± 22.6

150 42.8 ± 2.71 667 ± 31.7

250 40.6 ± 1.94 591 ± 46

300 39.7 ± 1.4 603 ± 51

360 43.2 ± 1.4 646 ± 28.8

410 37.4 ± 2.2 561 ± 32.5

At 40°C, the plasticizer is extracted after 2 days. The initial

decrease of the stress at rupture is due to a plasticization effect

of absorbed methanol.

50

45

40

35

30

25

20

15

10

5

20 400 60

• • ••

•

•

80 100 120 140 160

TEMPERATURE (°C)

ME

TH

AN

OL

AB

SO

RP

TIO

N W

T. %

60

50

40

30

20

10

100 35 45

TIME (DAYS)

ST

RE

SS

AT

RU

PT

UR

E (

MP

a)

403025205 15

•

•• • •

Fig.10 Methanol absorption of BESNO P40 grades

CH3OH + vvvvv N –H2 – C vvvvv vvvvv NH2 + vvvvv C – OCH3→←

=

O O

H

–

=

17

Fig. 11 Methanol aging: Stress at rupture in time at 40°C

The plasticizer is extracted after 2 hours at 70°C. The strong plastification effect of

methanol more than compensates for the plasticizer loss. The material becomes more

flexible. At 70°C, Rilsan® PA11 is not significantly degraded.

All these factors lead to the following picture for a service life – temperature relationship:

DATA AT 70°C

Time (days) Stress at rupture (MPa) Elongation at rupture (%)

0 53 ± 0.86 438 ± 13

1 31.9 ± 2.58 419 ± 25.1

2 32.8 ± 3.43 419 ± 32.8

8 33.7 ± 2.48 432 ± 19.6

42 34.9 ± 3.02 440 ± 22.7

120 33.8 ± 4.3 460 ± 44

160 33.1 ± 3.8 442 ± 30

2000 (5 1/2 years) 32 ± 5 320 ± 40

TEMPERATURE ( °C)

■■■ 20 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

LIF

ET

IME

(D

AY

S)

120 110 100 90 80 70 60 50

100000

10000

1000

100

10

1

water, pH=7

methanol

18

Fig. 12 Polyamide 11, BESNO P40 grades – lifetime in methanol contact

METHANOL PERMEATION DATA

Temperature in °C 4 23 40 50

PA11 unplasticized 6 18

PA11 plasticized 13.5 40 115 190

units: g mm/m2 day atm

The activation energies for the unplasticized and plasticized

grades are respectively:

39.4 kJ mol-1 and 43.1 kJ mol-1.

Pressure effects on permeability have been observed. As a

general rule, a tenfold increase in pressure results in a three-fold

increase in methanol permeation.

Conclusions:

• Methanol has a finite permeation rate through PA11 which has

to be taken into account in design.

• Liquid methanol efficiently extracts the plasticizer from PA11

plasticized grade “P40”. For umbilicals, this extraction has no

consequence on the integrity of the pipe.

• Methanol induces a softening and also polymer breakdown at

higher temperatures. We suggest 70°C as the maximum contin-

uous use temperature and 90°C for occasional temperature

peaks in the case of hydraulic hoses. For offshore flexible

pipes, the extraction of plasticizer and the modification of the

flexiblity can further reduce the continuous use temperature.

3.7 Influence of monoethylene glycol and ethylene

glycol-based hydraulic liquids on mechanical

properties

Monoethylene glycol and other ethylene glycols mixed in

different ratios with water are used as constituents of hydraulic

liquids in offshore applications. These liquids can extract plasti-

cizer from polyamide resin because the plasticizer has a rather

high solubility in glycol/water mixtures. This effect is shown in

the graph below. The tensile yield shifts to higher

modulus with the departure of the plasticizer.

To some extent glycol/water mixtures act as plasticizer them-

selves when absorbed by polyamide 11 resin.

All these phenomena are well known today and experience has

shown that they do not cause any particular problem in the

functioning of the subsea installation under ordinary working

conditions.

In the following, the phenomena are described in detail so that a

thorough understanding of the prevailing material behavior can

be developed.

1/TEMPERATURE

PE

RM

EA

BIL

ITY

(G

.MM

/M .

DA

Y)

50°C 40°C 30°C 20°C 10°C 0°C

1000

100

10

1

• BESNO TL

BESNO P40TL■

■

■

■

■

•

•

2

ST

RE

SS

AT

YIE

LD

(M

Pa

)

40

35

30

25

20

15

10

5

0 200 400 600 800 1000

TIME (DAYS)

40°C

70°C

METHANOL PERMEATION DATA

Fig. 14 Evolution of tensile stress of BESNO P40 TL 12mm bore

hoses in water/glycol 60/40

Fig. 13 Methanol permeability

19

The physical picture of the interactions

In a physical description of the ensemble

“umbilical filled with control fluid,” we

have to consider a closed system with

two phases, PA11 and control fluid, and

several components which, in time, can

interdiffuse between the two phases.

These components are the plasticizer

BBSA and constituents of the control

fluid, mainly glycols.

The effects can be described when the

solubility parameters of the diffusing

species and the diffusion kinetics are

known. The mathematics of diffusion in a

plane sheet are well described (Crank).

We will use some simple forms to illus-

trate the effects in a semiquantitative

manner.

For a particular umbilical, the ratio

between the two phases may be different

due to the particular tube dimensions.

The approach is best described in a

worked example.

Standard 1/2’’ hydraulic tube

ID = 12 mm WS = 1.5 mm

OD = 15 mm L = 100 mm

We calculate:

Fluid volume: 11.3 ml

Weight of tube (r = 1.05 mm): 5.4 g

The plasticizer content is on average

12.5% by weight of the resin.

BBSA content in a tube

with L = 100 mm: 675 mg

...................

...................

...................

...................

The maximum extractable amount of plasticizer adds up to approximately 6% by

weight. For a hydraulic fluid containing 45% glycol, the maximum plasticizer solubility

at ambient temperature is close to 6%. For a hydraulic fluid containing 25% glycol, the

solubility limit is 2.2 – 2.5%. At temperatures over 60°C, the plasticizer will be extract-

ed as it will become soluble in such a fluid.

22°C 60°C

pure water based, eg., Oceanic* HW 500 0.1 - 1 1.5 – 2.5

approx 25% glycol, eg., Oceanic HW 525 2.2 – 2.5 6.8 – 7.4

approx 40% glycol, eg., Oceanic HW 540 4.0 – 5.0 12.0 – 13.6

GLYCOL CONTENT ( %)

BB

SA

SO

LUB

ILIT

Y (

G/

L)

0 5 10 15 20 25 30 35 40 45

14

12

10

8

6

4

2

60°C

22°C

Fig. 15 The solubility of BBSA in glycol-based control fluids and its temperature

dependence

Control Fluid

BBSA BBSA

PA11

L

20

OD ID

*Hydraulic fluid manufactured by MacDermid Canning, PLC

3.8 Compatibility of RILSAN® BESNO P40 TLX and

BESNO P40 TLO resin with various offshore fluids

and chemicals

A variety of offshore fluids have specific functions in the explo-

ration and production process in offshore installations:

• Demulsifiers to break oil/water emulsions

• Corrosion inhibitors to slow corrosion of steel

• Bactericides to suppress the formation of acid-creating

bacteria

• Paraffin inhibitors which prevent the crystallization of

paraffins leading to a blocking of the pipes

• Scale inhibitors which prevent the formation of salt scales

capable of blocking of the pipes

• Oxygen scavengers which help prevent corrosion

Numerous formulations exist depending on the producer and

specific adaptions. However, the nature of the ingredients

remain essentially the same. Often even the compounds remain

the same and given formulations differ only in the amounts of

the constituents. The aim of this chapter is to analyze the behav-

ior of PA11 when exposed to the specific chemicals used in off-

shore applications. It supplements the information in the more

general chemical resistance table in section 3.4.

For convenience, the results of the tests of typical offshore fluids

are summarized in a final subsection 3.8.9.

For the screening tests, small dogbone samples were autoclaved

at a given temperature immersed in the chosen offshore fluid.

After a given time, 5 samples were retrieved on which tensile

tests were performed, weight changes monitored, and the

molecular weight changes analyzed.

All compatibility tests were performed at 60°C. Testing periods

were generally 2 years.

Given the typical activation energy for the chemical degradation

processes, a good behavior after 2 years at 60°C should give a

service life over 20 years at temperatures around 20°C.

21

3.8.1 Demulsifiers

Chemicals

• oxypropylated and/or oxyethylated alkylphenol

• ethylene oxide/propylene oxide copolymers

• glycol esters

• condensates of modified propylene oxide/ethylene oxide

• aromatic solvents, C7 to C10

(benzene, toluene, xylene, ethylbenzene)

TEST: PROCHINOR 2948 (AROMATIC SOLVENTS, NON-IONIC SURFACTANT)

Immersion time at 60°C Ultimate tensile Elongation at break Weight Inherent viscosity

strength % change % change % change % change

1 week - 2.7 - 0 + 1.26

1 month + 5.3 0 - 0.43

3 months + 85 + 2.7 - 2.37

6 months + 0.4 - 4.5 – 2.9

12 months + 10.5 + 0

18 months - 4 - 7.2 - 3.16

24 months + 1.4 - 1.2 - 3.26 no change

3.8.2 Corrosion inhibitors – oil soluble

Chemicals

• fatty amines

• imidazoline derivatives

• aromatic solvents

TEST: NORUST® PA23 (FATTY AMINES, IMIDAZOLINE DERIVATIVES, AROMATIC SOLVENT)

Immersion time at 60°C Ultimate tensile stress Elongation at break Weight Inherent viscosity

(% change) (% change) (% change) (% change)

1 week + 3.6 - 3.6 - 1.13

1 month + 3.4 - 6.3 - 2.0

3 months + 8.7 - 3.3 - 3.17

6 months + 1.8 - 9.0 - 4.07

12 months + 9.7 - 7.5

18 months + 1.0 - 6.0 - 5.37

24 months + 5.15 - 10.2 - 5.85 + 1.6

Comments

None of these chemicals have adverse effect on PA11.

Aromatic solvents exert slight swelling at temperatures above 40°C.

22

3.8.3 Corrosion inhibitors – water soluble

Chemicals

• fatty amines

• imidazoline derivatives

• sulphite derivatives

• water/glycol mixtures

TEST: NORUST® 743D (FATTY AMINES, IMIDAZOLINE DERIVATIVES, WATER/GLYCOL MIXTURES)

Immersion time at 60°C Ultimate tensile stress Elongation at Weight Inherent viscosity

(% change) break (% change) (% change) (% change)

1 week - 6.7 - 4.2 - 1.04

1 month + 0.2 - 2.4 - 3.06

3 months + 4.5 - 0.6 - 5.02

6 months + 2.0 - 3.3 - 5.82

12 months + 4.2 - 2.1

18 months + 5.0 + 2.4

24 months + 3.0 - 3.3 - 6.79 0

TEST: NORUST 720 (FATTY AMINES, IMIDAZOLINE DERIVATIVES, WATER)

1 week - 1.4 + 2.7 - 1.03

1 month + 2.2 + 0.9 - 3.22

3 months + 5.9 + 4.8 - 5.7

6 months - 5.7 - 3.0 - 6.63

12 months - 4.7 - 7.8 - 7.54

18 months - 3.0 - 3.6

24 months + 2.6 - 0.6 - 7.55 + 0.8

TEST: NORUST CR486 (FATTY AMINES, SULPHITE DERIVATIVES, WATER/GLYCOL MIXTURE)

1 week - 8.9 - 6.0 - 1.0

1 month - 5.7 - 10.0 - 2.86

3 months + 2.6 - 0.9 - 5.1

6 months - 4.5 - 3.3 - 5.89

12 months - 15 - 12.7

18 months - 36.6 - 38.4 - 6.33

24 months - 42.7 - 50.1 - 5.98 - 38

23

3.8.4 Corrosion inhibitors (oil soluble and water dispersible)

TEST: NORUST® PA23D (FATTY AMINES, IMIDAZOLINE DERIVATIVES, AROMATIC SOLVENT, ALCOHOL)



1 week + 5.1 - 1.8 - 0.74

1 month + 5.1 - 5.1 - 1.31

3 months + 9.1 + 0.3 - 2.37

6 months + 0.4 - 8.4 - 4.4

12 months + 6.5 - 5.1

18 months + 3.0 - 1.5 – 4.67

24 months + 8.3 - 2.7 - 6.02 + 4.0

3.8.5 Oxygen scavengers

Chemicals

• sodium bisulphite

NORUST SC45



1 week - 13.6 - 5.4 + 4.23

1 month - 10.3 - 1.5 + 5.78

3 months - 10.5 + 2.1 + 3.94

6 months - 13.9 + 3.6 + 4.67

12 months - 23.2 + 0.9

18 months - 80.2 - 97 + 5.22 - 65

24 months

24

3.8.6 Biocides

Chemicals

• ammonium quarternary salts

• ammonium salts

• aldehydes

• water/glycol mixtures

TEST: BACTIRAM® C85 (AMMONIUM QUARTERNARY SALTS, WATER)



1 week + 0.6 + 1.5 - 0.73

1 month + 8.7 + 5.1 - 2.79

3 months + 7.5 + 0.9 - 4.86

6 months + 7.3 - 0.6 - 5.32

12 months + 3.1 - 3.3

18 months - 6.8

24 months - 3.0 - 7.5 - 8.07 + 5.6

TEST: BACTIRAM CD30 (AMMONIUM SALTS, WATER/GLYCOL MIXTURE)

1 week - 15.8 - 0.6 - 0.09

1 month - 15.4 - 1.8 - 1.87

3 months - 9.3 + 5.7 - 2.44

6 months - 7.9 + 3.6 + 0.48

12 months -12.3 0.0

18 months - 18.8 - 8.8 - 1.59

24 months - 21.8 - 1.5 - 3.19 - 4

TEST: BACTIRAM 3084 (ALDEHYDES, WATER)

1 week - 3.2 - 1.8 + 0.77

1 month + 2.2 + 0.3 - 2.23

3 months + 0.2 - 5.4 - 3.53

6 months 0.0 - 5.4 - 4.1

12 months + 2.4 + 3.6

18 months - 8.9 - 9.4 + 0.65

24 months - 9.1 - 3.9 - 2.02 - 22.6

25

3.8.7 Paraffin inhibitors

Chemicals

• non-ionic surfactants

• polyacrylate

• aromatic solvents

TEST: PROCHINOR® AP 104 (NON-IONIC SURFACTANT, AROMATIC SOLVENTS)

Immersion time at 60°C Ultimate tensile Elongation at break Weight Inherent viscosity

stress (% change) (% change) (% change) (% change)

1 week + 1.4 - 1.5 + 0.8

1 month + 3.2 - 1.2 - 0.43

3 months + 7.5 + 1.2 - 2.44

6 months - 5.9 - 9.4 - 2.9

12 months + 3.0 - 4.8

18 months + 3.0 - 0.6 - 3.38

24 months + 4.9 - 0.1 - 4.35 + 8

TEST: PROCHINOR AP 270 (POLYACRYLATE. AROMATIC SOLVENTS)

1 week - 3.7 + 0.6 + 3.07

1 month + 0.6 - 1.5 - 0.04

3 months + 6.3 + 4.2 - 0.28

6 months + 2.0 + 1.5 + 1.37

12 months + 4.0 + 4.2

18 months - 1.0 + 6.0 - 1.84

24 months - 3.2 - 2.7 + 0.2 - 13.7

26

3.8.8 Scale inhibitors

Chemicals

• phosphonate

• polyacrylate

TEST: INIPOL® AD100 (POLYACRYLATE, WATER)



1 week - 0.6 + 2.7 - 0.58

1 month + 2.6 + 1.8

3 months + 11.5 + 9.4 - 3.83

6 months + 0.8 - 0.3 - 5.64

12 months - 4.9 - 0.9

18 months - 6.9 - 4.5 - 5.48

24 months - 9.7 - 3.6 - 5.5 - 16

TEST: INIPOL AD20 (PHOSPHONATE, WATER)

1 week - 3.4 + 4.5 + 1.88

1 month - 3.6 + 6.0 + 1.98

3 months - 82.2 - 97.8 + 2.5 - 48

6 months

12 months

18 months

24 months

3.8.9 Overview of chemical compatibility of RILSAN®

BESNO P40 TLX and BESNO P40 TLO with

common offshore chemicals

Offshore fluids are complex mixtures of several functional

chemicals which are either

• water based

• glycol/water mixture based

• hydrocarbon based

To quickly assess the compatibility of a given offshore fluid, it is

useful to examine the active constituents which are most often

given in the safety data sheet. Concentrations of the active

chemical species in the concentrated offshore fluid range

between 3 and 30%. In order to estimate the chemical compati-

bility, the most aggressive species must be identified. Its given

temperature limit can be taken as the limit for the given offshore

fluid. In the given list, no two chemicals have a synergistic

degradative effect, but some have antagonistic effects.

Furthermore, the pH value should be noted when it is given.

27

Chemical Liquid base Functions Compatibility class

oxypropylated and/or oxyethylated hydrocarbon demulsifier < water

alkylphenols “non ionic surfactants” water/glycol

ethylene oxide/propylene oxide copolymers hydrocarbon demulsifier < water

glycol esters hydrocarbon demulsifier < water

fatty amines hydrocarbon corrosion inhibitor class 1

water

water/glycol

imidazoline derivatives hydrocarbon corrosion inhibitor class 1

water

water/glycol

sulphite derivatives water corrosion inhibitor class 1

water/glycol

bisulphite salts water oxygen scavenger class 2

quaternary ammonium salts, water

“quats”, ammonium salts water/glycol biocides < water

aldehydes water biocides class 2

water/glycol

polyacrylates water paraffine inhibitors class 1

water/glycol scale inhibitors

organic phosphonates water scale inhibitors class 3

water/glycol corrosion inhibitors

organic sulfonates water scale inhibitors class 3

water/glycol corrosion inhibitors

hydrochloric acid, 15% water well stimulation class 4

hydrofluoric acid, 15% water well stimulation class 4

The sign “< water” means that the chemical is less agressive than water.

Fig. 16 Overview: compatibility

between PA11 grades BESNO

P40 TLO, TL and TLX and different

chemical classes

TEMPERATURE ( °C)

■■■ 1 YEAR ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 5 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 10 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■ 20 YEARS ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

LIF

ET

IME

(D

AY

S)

120 110 100 90 80 70 80 50 40 30 20

100000

10000

1000

100

10

1

Water

Class 1 Class 2 Class 3

Class 4

28

3.9 Compatibility with crude oil,

natural gas, carbon dioxide (CO2)

and hydrogen sulfide (H2S)

3.9.1 Compatibility with crude oil

Polyamide 11 is not chemically attacked

by hydrocarbons. Aliphatic hydrocarbons

have a very low solubility in polyamide

11, so that barrier properties are very

high. Low molecular weight aromatic

hydrocarbons can lead to some swelling

at higher temperatures as shown in the

following table.

The low solubility of hydrocarbons and

the high cohesive energy of polyamide

11 result in an excellent blistering

resistance (see section 3.11).

Whereas polyamide 11 is highly resistant

to hydrocarbons, certain other con-

stituents of crude oil can lead to perform-

ance limitations. These constituents are

water, organic acids, often referred to as

naphthenic acids, carbon dioxide and, to

a lesser extent, hydrogen sulfide. All

these chemicals create different acidities

depending on pressure, concentration

and overall fluid composition. Their

effects are described in the correspon-

ding chapters.

3.9.2 Compatibility with natural gas

Polyamide 11 is perfectly resistant to

methane, ethane, propane and butane as

well as higher hydrocarbons. Chemical

degradation can only be induced by acid

species, that is carbon dioxide and/or

hydrogen sulfide in combination with

water vapor.

The following test demonstrates the

chemical resistance:

Sheets of BESNO P40 TL with 2mm

thickness are immersed in natural gas at

100°C and 120 bar pressure for a given

time. Mechanical properties are checked.

Composition of the natural gas: 93%

hydrocarbon, 4% hydrogen sulfide, and

3% carbon dioxide and moisture.

Solvent Swelling at 20°C in % weight Compatibility

Benzene 7.5 good up to 70°C / swelling

Toluene 7 good up to 90°C / swelling

Cyclohexane 1 good

Petrol ether 1.5 good

Decaline < 1 good

Gasoline depends on type, mostly < 2% good

Kerosene depends on type, mostly < 2% good

Time Flexural modulus Yield strength Elongation Stress at rupture

(hours) (MPa) (MPa) at break (%) (MPa)

0 350 27 325 45

100 350 32.5 345 53

250 500 30.5 325 57

500 600 34.5 375 60.5

1000 400 28 360 63

2000 480 32 335 43

5000 460 34.5 430 55

500

450

400

350

300

250

200

150

100

50

1000 2000 3000 4000 5000 60000

• ••

•

TIME (HOURS)

ELO

NG

AT

ION

AT

BR

EA

K (

%)

••

•

Fig. 17 Polyamide 11, BESNO TL in natural gas - Evolution of elongation at break

29

CRUDE OIL EXPOSURE

METHANE OR NATURAL GAS EXPOSURE AT 20° C

No chemical degradation was observed. Fluctuations in the

mechanical properties are caused by the loss of plasticizer and

changes in moisture content of the gas.

In a typical field experience, polyamide 11 grade BESNO P40 TL

used as a lining for carbon steel pipe was aged in the following

conditions:

Temperature: 65°C

Natural gas: moist, with some condensate, H2S 17%, pH 5.5.

A sample was retrieved after 5 years of service. A chemical

analysis revealed no polymer degradation. Of the initial plasti-

cizer, 30% was lost.

As a conclusion, polyamide 11 grades BESNO TL, BESNO P40 TL,

BESNO P40 TLX and BESNO P40 TLO are compatible with hydro-

gen sulfide.

3.9.3. Compatibility with carbon dioxide (CO2)

Polyamide 11 is quite resistant to dry carbon dioxide. However,

carbonic acid formed by dissolution of carbon dioxide in water

under pressure can lead to chain degradation due to hydrolysis.

The rate of hydrolysis, as a function of acidity, is relatively well

known and described in section 3.5.

3.9.4. Compatibility with hydrogen sulfide (H2S)

Polyamide 11 is also resistant to hydrogen sulfide. As with car-

bon dioxide, only aqueous solutions which are acidic can lead to

chain degradation. Due to the low acidity and generally low par-

tial pressures of hydrogen sulfide in crude oil or natural gas,

degradation via hydrolysis seldom occurs.

For a series of tests, please refer to the preceeding section 3.9.2

“Compatibility with natural gas.”

3.10 Data on permeability of polyamide 11

The following data were obtained from a detailed study on 6 mm

extruded sheet.

RILSAN® BESNO P40 TL

P (bar) T (°C) Permeability Diffusion Solubility

/f (bar) cm3.cm/cm2.s.bar cm2/s cm3/cm3.bar

10-8 10-7

CH4 96 99 3.8 7.3 0.05

99 99 4.4 6.1 0.07

103 78 2 2.8 0.07

97 80 2 3.3 0.06

101 61 0.8 2.6 0.03

103 61 0.9 2.2 0.04

102 41 0.4

101 60 0.8 2.2 0.03

CO2 40 79 10 4.5 0.22

39 80 9.4 4.7 0.2

39 60 4.5 1.9 0.23

39 61 4.4 2.3 0.19

41 41 1.5 0.9 0.16

H2S 100/47.5 80 67 7.6 0.88

103/48 80 66 8.2 0.8

92/47 80 77 9.2 0.84

41/33 80 43 4.2 1.04

40/33 80 46 5.1 0.9

39/33 80 38 4.5 0.85

Elongation Stress at Stress at Elongation at Tensile at break (%) rupture (Mpa) yield (Mpa) yield (%) modulus (Gpa)

Aged sample 315 ± 38 46.7 ± 8,3 27.7 ± 0.5 42.4 ± 0.6 2.82 ± 0.02

Initial sample 359 ± 48 42.0 ± 3,0 – – 2.78 ± 0.008

TABLE COMPARING INITIAL AND AGED MECHANICAL PROPERTIES

30

Complementary data can be obtained from the literature.

PLASTICIZED POLYAMIDE 11

Fluid Conditions Permeation value/

cm3.cm/cm2.s.bar

CH4 70°C, 100 bars 9x10-9

CO2 70°C, 100 bars 50x10-9

H2O 70°C, 50 to 100 bars 2x10-6 to 7x10-6

H2S 70°C, 100 bars 1.5x10-7

METHANOL 23°C, 1 bar 3.7x10-9

data from IFP/ COFLEXIP OTC 5231

PLASTICIZED POLYAMIDE 11

Fluid Permeation value/cm3.cm/cm2.s.bar

70°C, 25 bar 70°C, 50 bar 70°C, 75 bar 70°C, 100 bar

CH4 0.53x10-7 1.4x10-7 1.9x10-7 1.8x10-7

CO2 2.3x10-7 5.8x10-7 7.8x10-7 7.8x10-7

H2O 3.6x10-6 6.5x10-6 3.4x10-6 1.9x10-6

data from NACE publication, Jan Ivar Skar (Norsk Hydro)

Some differences exist in reported values which can be

explained by different conditioning of the measured samples. For

example, some plasticizer loss leads to high barrier and lower

permeation.

3.11. Blistering resistance

The blistering resistance of a polymer material is directly related

to the solubility of gases in the material and its cohesive

strength. The blistering effect has its origin in the gas bubbles

formed when gas dissolved in the polymer material under high

pressure is expelled on a rapid decompression.

An extensive study has been performed at IFP (French Petroleum

Institute) which confirms the excellent blister resistance of

plasticized polyamide 11 according to the procedures outlined

in API 17J.

The following grades were tested on samples cut from an

extruded pipe, thickness 8 mm:

BESNO P40 TLX

BESNO P40 TLOS

Test conditions:

medium: 85% CH4 + 15% CO2

temperature: 90°C

pressure: 1000 bar

The decompression rate was explosive. The soak time was more

than 30 hours.

Result:

After 20 pressure/decompression cycles, no blister was

observed.

The same result is obtained when the samples were

preconditioned in oil or diesel fuel.

31

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ADDRESSES OF REGIONAL SALES OFFICES

After 14 years of research in a program

launched in 1958 by the French Institut de

Petrole, polyamide 11 was chosen as the

best material out of several hundred

tested. Today RILSAN® polyamide 11, the

unique polyamide from ATOFINA, looks

back at a service history of over 30 years

in the petroleum industry. The combined

qualities of flexibility, excellent impact

resistance even at low temperatures, high

resistance to aging and good compatibility

with products common to the petroleum

industry environment have made RILSAN

polyamide 11 an unequaled standard.

For even higher demands, especially at

higher temperatures or when the

combined high temperature and high

water content requirements are too

severe, ATOFINA proposes its unique

KYNAR® off-shore grade. KYNAR is a

thermoplastic fluoropolymer resin

developed by ATOFINA. Outstanding

thermomechanical properties combined

with exceptional chemical and aging

resistance enable KYNAR to meet the

most stringent demands.

The data given in this brochure describe the material performance of RILSAN® polyamide 11 in applications such aspneumatic or hydraulic tubes. For large diameter pipes or sheaths such as in flexible pipe the data give indicationsof lifetime limits, but further considerations might have to be taken into account. Hence this data may be inapplica-ble where lifetime and design specifications established by flexible pipe manufacturers or joint industry efforts haveresulted in new recommended practices or industry specifications.

The statements, technical information and recommendations contained herein are believed to be accurate as of the date hereof. As the condition and methods of use of

the products and of the information referred to herein are beyond our control, ATOFINA expressly disclaims any and all liability as to any results obtained or arising from

any use of the product or reliance on such information; NO WARRANTY OF FITNESS FOR ANY PARTICULAR PURPOSE, WARRANTY OF MERCHANTABILITY, OR ANY OTHER WAR-

RANTY, EXPRESS OR IMPLIED, IS MADE CONCERNING THE GOODS DESCRIBED OR THE INFORMATION PROVIDED HEREIN. The information provided herein relates only to the

specific product designated and may not be applicable when such product is used in combination with other materials or in any process. The user should thoroughly test

any application before commercialization. Nothing contained herein should be taken as an inducement to infringe any patent and the user is advised to take appropriate

steps to be assured that any proposed use of the product will not result in patent infringement.

BEFORE HANDLING THIS MATERIAL, READ AND UNDERSTAND THE MSDS (MATERIAL SAFETY DATA SHEET) FOR ADDITIONAL INFORMATION ON PERSONAL PROTECTIVE EQUIP-

MENT AND FOR SAFETY, HEALTH AND ENVIRONMENTAL INFORMATION.

RILSAN® Polyamide 11

in Oil & Gas

Off-shore Fluids

Compatibility Guide

ATOFINA Chemicals, Inc. 2000 Market Street Philadelphia, PA 19103-3222 Telephone: (215) 419-7000

ATOFINA Canada, Ltd. 700 Third Line Oakville, Ontario L6J5A3 Canada, Telephone: (905) 827-9841

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RILSAN Polyamide 11 in Oil & Gas Off-shore Fluids ... · RILSAN® Polyamide 11 in Oil & Gas Off-shore Fluids Compatibility Guide ATOFINA Chemicals, Inc. 2000 Market Street Philadelphia,