Carbon Fiber Armors Applied to Presalt Flexible Pipe Developments

Spread moored FPSO (Floating Production and Storage Offloading) vessels are generally used for the large West African oil fields. The oil is transferred from the FPSO to shuttle tankers via an Oil Loading Terminal (OLT). 2 to 3 large diameter flexible lines are connecting the FPSO to the OLT. The final connection between the OLT and the shuttle tanker is made by floating hoses. The single length of each flexible pipe can be typically 2,300 meters or higher, and the internal diameter is generally very large in the order of 15_23″ to minimize the pressure drop and the offloading time. Conventional flexible pipe is the most suitable solution for this application. However, its long length and large diameter require a large number of buoyancy modules which are necessary to support the substantial weight generated by the steel armor wires. An alternative to steel is Carbon Fiber Composite (CFC). This material is not only twice as strong and five times lighter than a high strength steel but it is also characterized by its exceptional performance in fatigue. As the weight of the composite armor flexible pipe is significantly reduced, the use of buoyancy is no longer necessary. The pipe can also be manufactured in a single length without intermediate connection. A qualification program based on a 19″ internal diameter prototype has been launched. This is the first time that a large internal prototype with Carbon Fiber Composite Armor (CFA) and end-fittings have been designed and manufactured. The main goals are to confirm the suitability of the CFA flexible pipe for oil offloading application in accordance with the design tools. The mechanical behavior responses of the CFA are monitored by strain gages when the flexible pipe is in straight and curved positions under internal pressure and bending cycles. The paper will present the main mechanical properties and the overall performance of the flexible pipe designed and tested. The economic viability will be demonstrated by showing how the CFC material cost is positively offset by the removal of the buoyancy modules and a faster offshore installation.

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Full Generic Qualification of Nylon 12 Carbon Fiber Composite for Dynamic Thermoplastic Composite Pipe and Hybrid Flexible Pipe Applications

10.4043/31266-ms ◽

2021 ◽

Author(s):

Carsten Schuett ◽

Alexandre Paternoster

Keyword(s):

Carbon Fiber ◽

End Of Life ◽

Material Characterization ◽

Stress Rupture ◽

Thermoplastic Composite ◽

Flexible Pipe ◽

Knowledge Based ◽

Composite Pipe ◽

Nylon 12 ◽

Rupture Mode

Abstract Composite structures are used as corrosion insensitive load bearing reinforcement in dynamic Thermoplastic Composite Pipe (TCP) and Hybrid Flexible Pipe (HFP) applications. The qualification of such structures can follow different strategies: product level versus material characterization. DNVGL-ST-F119 proposes a generic knowledge-based approach based on a testing pyramid. The pyramid allows a generic material characterization for a large number of conditions. Testing of dedicated specimens in constant media exposure measures the actual properties and changes of the material. Regression data is obtained for end-of-life properties. Simulations can be conducted using these properties to determine performance of the product in any state and condition and validate any load cases through classical stress combination. The characterization for VESTAPE® Nylon 12 Carbon Fiber thermoplastic composite (CF-PA12) covers all failure mechanisms for matrix, fiber and interface in static, dynamic and stress rupture mode for virgin, fully hydrocarbon saturated and aged to end of life in saturated condition. Each condition assessment is carried out in complete temperature dependency for subzero, room temperature, intermediate and maximum use temperature of 176°F (80°C). Fatigue testing covers runtimes of 106 cycles whereas stress rupture assessment exceeds 12,500h which corresponds to almost 1.5 years. With dense data populations for both regression curves and static test results the coefficient of variation is controlled. All characterization logic and data are analyzed for validity and certified by the official body of the DNV-GL. The material characterization enables simulation of a variety of application designs in predictive engineering and a simplified study is made for a dynamic gas injection jumper to demonstrate relevant occurring load cases. Utilizing all data and approaches allows to define the overall application envelope of the material. For the case of the thermoplastic composite of CF-PA12 it covers static flowlines, dynamic jumpers, service lines up to dynamic risers in sour crude service up to 176°F (80°C). The knowledge-based approach allows for economic design in engineering cases without compromising safety.

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The Study of a New Concept of Flexible Pipe With Carbon Fiber/Epoxy Reinforced Inner Sheath

Volume 5A: Pipelines, Risers, and Subsea Systems ◽

10.1115/omae2017-61069 ◽

2017 ◽

Author(s):

Chongyao Zhou ◽

Zhiming Huang ◽

Yongtian Kang ◽

Dagang Zhang ◽

Naiquan Ye ◽

...

Keyword(s):

Composite Material ◽

Carbon Fiber ◽

Laminated Composite ◽

Flexible Pipe ◽

Inner Pressure ◽

Offshore Industry ◽

Pressure Resistance ◽

Steel Weight ◽

Carbon Fiber Epoxy ◽

Fea Analysis

Flexible pipe has been widely used in offshore industry for many years. The traditional composite structure of flexible pipe consists of many layers, including multiple metallic layers, such as tensile armor, pressure armor and carcass, as well as nonmetallic layers, such as sheath and liner. Typical flexible pipe is heavy and requires complex manufacturing process, especially pressure armor and carcass manufacturing. Therefore, there is a desire to find a replacement to pressure armor and carcass. With the recent development of a new composite material with lighter weight and higher strength, it now becomes possible. This new composite material is called epoxy compounded carbon fiber (EP/CF). Carbon fiber is 10 times stronger than steel, while it is only 1/5 of the steel weight. Epoxy protects carbon fiber from environmental conditions such as high temperature and corrosion, also bond carbon fiber together and help to redistribute the loading between carbon fibers. This paper is to present a new concept of flexible pipe by applying the EP/CF material to flexible design. In this new flexible concept, EP/CF is used to strengthen the inner sheath by surface activation treatment of sheath material. This provides excellent hoop strength to resist the inner pressure, hence provides a good replacement to the pressure armor and carcass. A new FEA analysis method with ABAQUS is also presented in this paper. In the analysis approach, all helix fibers are modelled using predefined beam element, and EP/CF reinforced inner sheath is modeled using laminated composite shell. Nonlinear FEA analysis is carried out in ABAQUS to investigate the tension and bending behavior of flexible pipe with reinforced inner sheath, including the performance of inner pressure resistance, which is one of the key performances. Analysis is also carried out to study the benefit of using EP/CF on outer sheath reinforcement for collision protection. Lastly, the economics and feasibility of this concept are discussed, and conclusions are drawn.

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Effects of high pressure on the crystallization of carbon fiber reinforced polyetheretherketone (CF/PEEK) laminate composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177519 ◽

1990 ◽

Vol 48 (4) ◽

pp. 876-877

Author(s):

Hong-Ming Lin ◽

C. H. Liu ◽

R. F. Lee

Keyword(s):

High Pressure ◽

Carbon Fiber ◽

Sample Surface ◽

High Yield ◽

Fiber Reinforced ◽

Laminate Composites ◽

Peek Composite ◽

Continuous Carbon Fiber ◽

Carbon Fiber Reinforced

Polyetheretherketone (PEEK) is a crystallizable thermoplastic used as composite matrix materials in application which requires high yield stress, high toughness, long term high temperature service, and resistance to solvent and radiation. There have been several reports on the crystallization behavior of neat PEEK and of CF/PEEK composite. Other reports discussed the effects of crystallization on the mechanical properties of PEEK and CF/PEEK composites. However, these reports were all concerned with the crystallization or melting processes at or close to atmospheric pressure. Thus, the effects of high pressure on the crystallization of CF/PEEK will be examined in this study.The continuous carbon fiber reinforced PEEK (CF/PEEK) laminate composite with 68 wt.% of fibers was obtained from Imperial Chemical Industry (ICI). For the high pressure experiments, HIP was used to keep these samples under 1000, 1500 or 2000 atm. Then the samples were slowly cooled from 420 °C to 60 °C in the cooling rate about 1 - 2 degree per minute to induce high pressure crystallization. After the high pressure treatment, the samples were scanned in regular DSC to study the crystallinity and the melting temperature. Following the regular polishing, etching, and gold coating of the sample surface, the scanning electron microscope (SEM) was used to image the microstructure of the crystals. Also the samples about 25mmx5mmx3mm were prepared for the 3-point bending tests.

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Enhanced performance of supercapacitors by constructing a “mini parallel-plate capacitor” in an electrode with high dielectric constant materials

Journal of Materials Chemistry A ◽

10.1039/d0ta04364h ◽

2020 ◽

Vol 8 (32) ◽

pp. 16661-16668

Author(s):

Huayao Tu ◽

Shouzhi Wang ◽

Hehe Jiang ◽

Zhenyan Liang ◽

Dong Shi ◽

...

Keyword(s):

Dielectric Constant ◽

Carbon Fiber ◽

Parallel Plate ◽

Sandwich Structure ◽

High Dielectric Constant ◽

Parallel Plate Capacitor ◽

Plate Capacitor ◽

Fiber Metal ◽

High Dielectric ◽

Mini Plate

The carbon fiber/metal oxide/metal oxynitride layer sandwich structure is constructed in the electrode to form a mini-plate capacitor. High dielectric constant metal oxides act as dielectric to increase their capacitance.

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