10-nylon-11-in-oil-gas1.pdf

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 as pneumatic or hydraulic tubes. For large diameter pipes or sheaths such as in flexible pipe the data give indications of lifetime limits, but further considerations might have to be taken into account. Hence this data may be inapplicable where lifetime and design specifications established by flexible pipe manufacturers or joint industry efforts have resulted 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 WARRANTY, 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 EQUIPMENT AND FOR SAFETY, HEALTH AND ENVIRONMENTAL INFORMATION.

PA11

1 2 3

CONTENTS

1

General introduction and material overview

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

Influence of monoethyleneglycol and ethyleneglycol based hydraulic liquids on mechanical properties

19

3.7 3.8

Page 2

®

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

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

3.9

2

1 A range of materials comes into play to make up the entire structure:

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.

• 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, unlimited seamless tube length and long life in harsh offshore environments.

Fig.1 Umbilical cross sections

PA11 hydraulic hose 1”

PA11 hydraulic hose 1/2”

Power cables

Outer sheath PP fillers

PP fillers

1

Tape binder Steel armor wires

PE sheath PP separator and outer sheath

Steel armor wires

PA11 hydraulic hose 1/2”

3

Fig. 2 Morphology of a semicrystalline polymer a. ● ● ● ●

●

●

d.

● ●

The following table gives an outline of the scope of properties of thermoplastic polymers which can be found in offshore applications today.

lc

● ● ● ●

● ● ●

●

●

b.

Lp la

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

55 – 70

32 – 61

75 – 77

5.7

26

44

c.

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.

Shore D hardness

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 amorphous 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).

LOI (%)

42

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 significantly lower water absorption results in better aging resistance, higher chemical resistance 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

2800 (1200)

2200

1300

300

2.5 8.5

2.7 9.5

1.1 1.9

1.2 1.9

Charpy notched impact ISO 180/1A (kJ/m2) 23°C - 40°C

5.3 (24) X

8 (30) X

23 13

N.B. 7

ISO 527 Tensile stress (MPa) Tensile elongation (%) Elongation at rupture (%)

87 (77) 5 (25) 60 (300)

85 (70)

36 22 360

21 – 380

Flexural modulus (MPa) 50% RH (23°C) Water absorption 50% RH (23°C) in water immersion

15 – 200

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

4

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 network. Especially methanol has a significant absorption rate and must be considered in certain applications. Please refer to section 3.6.

Although polyamide 11 is highly resistant to aging and chain breakdown, the reaction 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 accelerated 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 performance requirements and more precise conditions. The reader should refer to data on temperature – lifetime correlations in section 3.5.

REACTION: HYDROLYSIS

PA CHAINS WITH H-BONDING

=

O

vvvvv

C–N vvvvv +H2O → ←

vvvvv

CO2H +

vvvvv

NH2

–

H–N C=O

IIIIIII

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 A high viscosity and plasticized grade developed for pipe extrusion especially for the inner pressure layer of flexible pipe. BESNO P40 TLO A high viscosity and plasticized grade 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.

H

H–N C=O

IIIIIII

H–N C=O

O=C N–H IIIIIII O=C N–H IIIIIII O=C H–N

A special molecule, butyl-benzene-sulfonamide 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.

C=O IIIIIII H-N IIIIIII

H–N C=O

O=C N–H IIIIIII O=C N–H IIIIIII O=C

BESNO TL A high viscosity unplasticized grade adapted for pipe extrusion. BMNO TLD An injection molding grade.

H–N C=O

BESNO P20 TL A medium plasticized, high viscosity extrusion grade for pipe and sheath extrusion.

BUTYL-BENZENE-SULFONAMIDE OR BBSA

O II S II O

These grades are all of natural color. Certain colored grades or color master batches are also available.

N H

5

FLEXURAL TESTS ACCORDING TO ISO 178 : 93 Temperature

°C

-40

-20

23

80

Flexural modulus (dry material)

MPa

1950

1350

320

165

Flexural modulus (after conditioning 15 days at 23°C, 50% R.H.)

MPa

2050

1150

280

160

FLEXURAL TESTS ACCORDING TO ASTM D790

Temperature

2

Flexural modulus (dry material)

°C

23

80

MPa

330

170

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.

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

2.1 Mechanical properties and design parameters DENSITY ASTM D792

IMPACT TESTS ACCORDING TO ISO 179 :93 CA Temperature

1.05 g/cm3

Notched HARDNESS ISO 2039/2 (R SCALE) ISO 868 (D SCALE) COMPRESSION STRENGTH ASTM D695 (23°C)

°C

-40

-20

0

23

KJ.m-2

6.8

9.9

52.9

N.B.

75 61

50 MPa

ABRASION RESISTANCE ISO 9352 : 1995(F) (loss in weight after 1000 rev under 500g H18 wheel) 22 mg

2.2 Thermal properties THERMAL CONDUCTIVITY Temperature (°C) K (W/m°K)

THERMAL EXPANSION ASTM E 821

39

61

82

102

122

142

163

182

202

223

0.21

0.24

0.24

0.24

0.24

0.24

0.25

0.25 0.25

0.25

HEAT DISTORTION TEMPERATURE

SOFTENING POINT

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

6

HEAT CAPACITY

Measured by D.S.C. Temperature (°C) cal/g.°C

20

50

80

120

160

200

230

260

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

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 crystalline 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.

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 characteristic relaxational transitions. The first zone is a low temperature high modulus zone which starts to soften around –20°C. Due to efficient low temperature relaxations (centered around –80°C) PA11 is tough even at these very low temperatures.

For a textbook on the comprehensive analysis of DMA data refer to Anelastic and Dielectric Effects in Polymer Solids by N.G. McCrum, B.E. Read, G. Williams; Dover Publication, New York, 1991.

STORAGE MODULUS E' (Pa) LOSS MODULUS E" (Pa)

Between –20 and 40°C the material softens gradually to attain its characteristic

1.00E+10

E' E" 1.00E+09

1.00E+08

1.00E+07 -140 -120 -100 - 80 -60

-40

-20

0

20

40

60

80

100 120 140 160 180

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

7

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.”

3

Heat aging performance has been established based on accelerated tests in a ventilated oven. In most cases the performance is monitored by tensile experiments. An example of a typical test series is given in the figure below.

Overview of aging properties of polyamide 11

• 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.

• mean values

450 ELONGATION AT BREAK (%)

Polyamide 11 is subject to aging phenomena. These phenomena are rather varied and depend on the specific environment. The most important factors inducing aging and subsequent loss of properties for polyamides are:

500

•

400 350

•

•

•

•

300 250 200 150 100

•

50

• 0

50

100

150

200

250

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

300

350

8

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.

4 ■■■

20 YEARS

■■■

10 YEARS 5 YEARS

■■■

1 YEAR

■■■

3.5

■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

LOG TIME (DAYS)

3 2.5

■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

2

+ .5 0

+

150

+

140

+

130

+

120

+

+

110

Machined Injected Linear (machined) Linear (injected)

100

+

90

+

Conditions: Xenon lamps with filters eliminating radiation with wave lengths less than to 300 nm.

80

Intermittent exposure – equal periods of light and darkness.

TEMPERATURE ( °C) Fig. 6 Laboratory aging of BESNO P40 TLX: Xenotest 1200

400

ELONGATION AT BREAK (%)

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%.

•

350

•

300

•

250

Black panel temperature in the measurement cabinet: 65°C ± 2°C before spraying 45°C ± 2°C after spraying

200 150 100

•

50

• 500

0

1000

1500

2000

2500

TIME (HOURS)

TIME (h)

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 UVlight combined with natural weathering. These tests include cycles where the samples 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.

1.5 1

3.2. UV aging

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

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.

9

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

3.3 Chemical aging

40

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 thermoplastics. Polyamide 11 can be used in conjunction with a great variety of standard offshore chemicals. A detailed description of compatibilities is given in sections 3.8 and 3.9. Because chemical species attack thermoplastic 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 hydrolysis. 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 related to offshore applications, section 3.5 describes the phenomenon in detail.

35 ELONGATION AT BREAK (%)

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.

30 25 YI 20 15

•

•

10

•

•

5• 0

500

1000

1500

2000

TIME (HOURS)

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

2.5

good up to 60°C / swelling

1

good up to 60°C

Ethylene glycol Glycerol

2500

10

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

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

magnesium chloride

11

Concentration

20°C

40°C

60°C

90°C

G

G

G

G

sea water

G

G

G

G

carbonated water

G

G

G

G

bleach

L

P

P

P

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

P

P

G

G

Other Inorganic Materials water

hydrogen peroxide

potassium permanganate

See section 3.5

20%

5%

agricultural sprays

Organic Bases aniline

Pure

L

P

P

P

pyridine

Pure

L

P

P

P

G

G

L

L

20%

G

G*

G*

L

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

urea diethanolamine

Inorganic Bases

12

Concentration

20°C

40°C

60°C

90°C

1%

G

L

P

P

10%

G

L

P

P

1%

G

L

L

P

10%

G

L

P

P

50%

G

L

P

P

P

P

P

P

P

P

P

P

L

P

P

P

methyl bromide

G

P

methyl chloride

G

P

trichloroethylene

L

P

perchloroethylene

L

P

carbon tetrachloride

P

trichloroethane

L

Freon

G

Phenols

P

P

P

P

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

Inorganic Acids hydrochloric acid

sulphuric acid

phosphoric acid nitric acid chromic acid sulphur dioxide

10%

Halogenated solvents

P

Esters and Ethers

13

Concentration

20°C

40°C

60°C

90°C

Various Organic Compounds anethole

G

ethylene chlorohydrin

P

P

L

ethylene oxide

G

G

P

carbon disulphide

G

L

L

furfuryl alcohol

G

G

tetraethyl lead

G

diacetone alcohol

G

G

L

P

glucose

G

G

G

G

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

P

Organic Acids and Anhydrides acetic acid

refer to section 3.5 – role of acidity in hydrolysis

14

Concentration

20°C

40°C

60°C

90°C

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

Hydrocarbons

Alcohols methanol

Pure

G

L

P

ethanol

Pure

G

L

P

G

L

P

G

G

L

P

glycol

G

G

L

P

benzyl alcohol

L

P

P

P

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

butanol glycerine

pure

Aldehydes and Ketones acetone

Pure

15

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).

CO2H +

vvvvv

NH2

vvvvv

C – N vvvvv +H2O

–

vvvvv

=

O

→ ←

H <= hydrolysis

polycondensation =>

The hydrolysis chain scission reaction is not significant in ordinary use at ambient temperatures. 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.

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

150 140 ----------------------------------------------

90 80 70 60 0

10

100

1000

AGING TIME (DAYS)

10 years 20 years -----------------------

100

5 years

----------------------------

110

1 year -----------------------------------

120

----------------------------------------------

AGING TEMPERATURE (°C)

1 month 130

10000

100000

16

Fig. 8 Hydrolysis resistance as a function of pH 100000

■

LIFETIME (DAYS)

10000

■■■

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

■■■

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

■■■

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

1000

▲ ■■■

•

■■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 1 YEAR ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ▲ ■

•

■

100 ■ ▲ ■

•

An aggravating factor for the hydrolysis process is the presence of acids – either carbonic acid produced under CO2 pressure or naphthenic acids possibly present in crude oil.

10

■ ▲

•

•

1 140 130

120

110

100

90

80

70

TEMPERATURE ( °C) Fig. 9 Aging behavior as a function of pH 100000

■

10000

■■■

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

■■■

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

■■■

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

■

LIFETIME (DAYS)

Carbonic acid formed by the dissolution of carbon dioxide in water under pressure causes a more severe polymer performance 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 thickness can be observed.

■ pure water pH=7 ▲ pH=5 CO2 liquid ■ pH=4 CO2 gas pH=4 CO2 liquid

■

■

1000 ■■■

•

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

100

•

◆

◆ ■

• 10

◆

■ pure water pH=7

•

■

pH=4 CO2 liquid

◆ Strong organic acid

• 1 140 130

120

110

100

90

TEMPERATURE ( °C)

80

70

17

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

The effect of methanol absorption on mechanical properties is outlined in the figure below. 60 STRESS AT RUPTURE (MPa)

3.6 Influence of methanol on aging and mechanical properties, permeability data

50

•

40

•

•

••

30 20 10

0

5

10

15

25 20 TIME (DAYS)

30

35

40

45

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

• A methanolysis reaction which leads to a loss of polymer molecular weight.

A rapid drop in strength as measured by stress at rupture is observed due to deplasticization. The resin strength then equilibrates in methanol leading to stable properties.

O =

=

O –

CH3OH + vvvvv N – H2 – C vvvvv

→ ← vvvvv NH2 + vvvvv C – OCH3

H

50

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.

METHANOL ABSORPTION WT. %

45

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.

40 35

•

30 25 20

•

15 10

•

•

20

40

•

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

5 0

60

80

100

120

TEMPERATURE (°C)

Fig.10 Methanol absorption of BESNO P40 grades

140

160

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.

18

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

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: Fig. 12 Polyamide 11, BESNO P40 grades – lifetime in methanol contact 100000

LIFETIME (DAYS)

10000

■■■

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

1000

100 water, pH=7 methanol 10

1 120

110

100

90

TEMPERATURE ( °C)

80

70

60

50

19

METHANOL PERMEATION PERMEATION DATA DATA METHANOL

Temperature in °C

4

23

PA11 unplasticized

6

18

13.5

40

PA11 plasticized

40

50

115

190

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 plasticizer 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.

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.

To some extent glycol/water mixtures act as plasticizer themselves when absorbed by polyamide 11 resin.

Fig. 13 Methanol permeability

•

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.

BESNO TL

■ BESNO P40TL

■ ■

100

In the following, the phenomena are described in detail so that a thorough understanding of the prevailing material behavior can be developed.

■

•

■

10

• Fig. 14 Evolution of tensile stress of BESNO P40 TL 12mm bore hoses in water/glycol 60/40

1 50°C

40°C

30°C

20°C

10°C

40

0°C

1/TEMPERATURE

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 continuous 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.

35 STRESS AT YIELD (MPa)

PERMEABILITY (G.MM/M2.DAY)

1000

30 25 20 40°C 70°C

15 10 5

0

200

400

600

TIME (DAYS)

800

1000

20

14

The physical picture of the interactions

Control Fluid

12 BBSA SOLUBILITY (G/L)

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.

60°C 22°C

10 8 6 4

PA11

2 BBSA

BBSA

0

5

10

15

20

25

30

35

40

45

GLYCOL CONTENT ( %) 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 illustrate 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 L

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

OD ID ................... ...................

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

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

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 extracted 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

*Hydraulic fluid manufactured by MacDermid Canning, PLC

21

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 exploration and production process in offshore installations: • Demulsifiers to break oil/water emulsions

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.

• Corrosion inhibitors to slow corrosion of steel • Bactericides to suppress the formation of acid-creating bacteria

All compatibility tests were performed at 60°C. Testing periods were generally 2 years.

• Paraffin inhibitors which prevent the crystallization of paraffins leading to a blocking of the pipes

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.

• 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 behavior of PA11 when exposed to the specific chemicals used in offshore applications. It supplements the information in the more general chemical resistance table in section 3.4.

22

3.8.1 Demulsifiers Chemicals

Comments

• oxypropylated and/or oxyethylated alkylphenol

None of these chemicals have adverse effect on PA11. Aromatic solvents exert slight swelling at temperatures above 40°C.

• 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 strength % change

Elongation at break % change

Weight % 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

Inherent viscosity % change

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 (% change)

Elongation at break (% change)

Weight (% 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

Inherent viscosity (% change)

+ 1.6

23

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 (% change)

Elongation at break (% change)

Weight (% 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

Inherent viscosity (% change)

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

24

3.8.4 Corrosion inhibitors (oil soluble and water dispersible) TEST: NORUST® PA23D (FATTY AMINES, IMIDAZOLINE DERIVATIVES, AROMATIC SOLVENT, ALCOHOL)

Immersion time at 60°C

Ultimate tensile stress (% change)

Elongation at break (% change)

Weight (% change)

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

Inherent viscosity (% change)

- 6.02

+ 4.0

Inherent viscosity (% change)

3.8.5 Oxygen scavengers Chemicals • sodium bisulphite NORUST SC45

Immersion time at 60°C

Ultimate tensile stress (% change)

Elongation at break (% change)

Weight (% change)

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

24 months

+ 5.22

- 65

25

3.8.6 Biocides Chemicals • ammonium quarternary salts • ammonium salts • aldehydes • water/glycol mixtures TEST: BACTIRAM® C85 (AMMONIUM QUARTERNARY SALTS, WATER)

Immersion time at 60°C

Ultimate tensile stress (% change)

Elongation at break (% change)

Weight (% change)

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

Inherent viscosity (% change)

+ 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

26

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 stress (% change)

Elongation at break (% change)

Weight (% 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

Inherent viscosity (% change)

+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

27

3.8.8 Scale inhibitors Chemicals

• phosphonate • polyacrylate TEST: INIPOL® AD100 (POLYACRYLATE, WATER)

Immersion time at 60°C

Ultimate tensile stress (% change)

Elongation at break (% change)

Weight (% change)

1 week

- 0.6

+ 2.7

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

Inherent viscosity (% change)

- 0.58

- 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 compatibility, 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.

28

100000

Fig. 16 Overview: compatibility between PA11 grades BESNO P40 TLO, TL and TLX and different chemical classes

Water Class 1 Class 2 Class 3

LIFETIME (DAYS)

10000

■■■

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

■■■

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

■■■

5 YEARS ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■Class ■■■■■4 ■■■

■■■

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

1000

100

10

1 120

110

100

90

80

70

80

50

40

30

20

TEMPERATURE ( °C)

Chemical

Liquid base

Functions

Compatibility class

oxypropylated and/or oxyethylated alkylphenols “non ionic surfactants”

hydrocarbon water/glycol

demulsifier

< water

ethylene oxide/propylene oxide copolymers

hydrocarbon

demulsifier

< water

glycol esters

hydrocarbon

demulsifier

< water

fatty amines

hydrocarbon water water/glycol

corrosion inhibitor

class 1

imidazoline derivatives

hydrocarbon water water/glycol

corrosion inhibitor

class 1

sulphite derivatives

water water/glycol

corrosion inhibitor

class 1

bisulphite salts

water

oxygen scavenger

class 2

quaternary ammonium salts, “quats”, ammonium salts

water water/glycol

biocides

< water

aldehydes

water water/glycol

biocides

class 2

polyacrylates

water water/glycol

paraffine inhibitors scale inhibitors

class 1

organic phosphonates

water water/glycol

scale inhibitors corrosion inhibitors

class 3

organic sulfonates

water water/glycol

scale inhibitors corrosion inhibitors

class 3

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.

29

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 constituents of crude oil can lead to performance 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 corresponding chapters.

CRUDE OIL EXPOSURE

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

METHANE OR NATURAL GAS EXPOSURE AT 20° C

Time (hours)

Flexural modulus (MPa)

Yield strength (MPa)

Elongation at break (%)

Stress at rupture (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

3.9.2 Compatibility with natural gas

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.

450 ELONGATION AT BREAK (%)

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.

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

500

•

400

•

350 300

•

• •

• •

250 200 150 100 50 0

1000

2000

3000 TIME (HOURS)

4000

5000

6000

30

TABLE COMPARING INITIAL AND AGED MECHANICAL PROPERTIES Elongation at break (%)

Stress at rupture (Mpa)

Stress at yield (Mpa)

Elongation at yield (%)

Tensile 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

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.

3.10 Data on permeability of polyamide 11 The following data were obtained from a detailed study on 6 mm extruded sheet.

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.

RILSAN® BESNO P40 TL P (bar) /f (bar)

T (°C)

Permeability cm3.cm/cm2.s.bar 10-8

Diffusion cm2/s 10-7

Solubility cm3/cm3.bar

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

40

79

10

4.5

0.22

39

80

9.4

4.7

0.2

39

60

4.5

1.9

0.23

3.9.4. Compatibility with hydrogen sulfide (H2S)

39

61

4.4

2.3

0.19

Polyamide 11 is also resistant to hydrogen sulfide. As with carbon dioxide, only aqueous solutions which are acidic can lead to chain degradation. Due to the low acidity and generally low partial pressures of hydrogen sulfide in crude oil or natural gas, degradation via hydrolysis seldom occurs.

41

41

1.5

0.9

0.16

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

A sample was retrieved after 5 years of service. A chemical analysis revealed no polymer degradation. Of the initial plasticizer, 30% was lost.

CH4

As a conclusion, polyamide 11 grades BESNO TL, BESNO P40 TL, BESNO P40 TLX and BESNO P40 TLO are compatible with hydrogen 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.

For a series of tests, please refer to the preceeding section 3.9.2 “Compatibility with natural gas.”

CO2

H2S 100/47.5

31

Complementary data can be obtained from the literature.

3.11. Blistering resistance

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

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

PLASTICIZED POLYAMIDE 11 Fluid

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.

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.

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.

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Inipol®, NoRust®, Prochinor® and Bactiram® are registered trademarks of CECA, S.A. Rilsan® is a registered trademark of Atofina. ATOFINA S.A. - Société Anonyme au capital de 2 953 089 200 F - RCS Nanterre B 319 632 790 4, cours Michelet - La Défense 10 - Cedex 42 - 92091 Paris La Défense (France) - Tél. 149 00 80 80 - Téléfax 149 00 83 96 © 2003 ATOFINA Chemicals, Inc. All rights reserved.

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 as pneumatic or hydraulic tubes. For large diameter pipes or sheaths such as in flexible pipe the data give indications of lifetime limits, but further considerations might have to be taken into account. Hence this data may be inapplicable where lifetime and design specifications established by flexible pipe manufacturers or joint industry efforts have resulted 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 WARRANTY, 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 EQUIPMENT 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 www.AtofinaChemicals.com