Corrosion Testing of Armour Wire in Simulated Annulus Environments of Flexible Pipelines: An Update

2003 ◽  
Author(s):  
Richard Clements ◽  
Andrew D. Ethridge
Keyword(s):  
Deionized Water ◽  
Small Scale ◽  
General Corrosion ◽  
Flexible Pipe ◽  
Scale Test ◽  
Condensed Water ◽  
Test Cells ◽  
Sour Service ◽  
First Time ◽  
Permeation Models

This paper describes further investigations, utilising small scale test cells, into the general corrosion which can occur on wires within the inherent annulus space in a flexible pipe, particularly, and for the first time, in a sour service (H2S containing) environment. The work enhances data presented previously in 2002. Tests have been performed in cells specifically designed to simulate, as closely as possible, the environment and confines of a flexible pipe annulus, using solutions of both deionized water and seawater (to represent seawater flooding and condensed water). The systems were saturated with CO2 and H2S to simulate permeation of gases through the polymer pressure sheath (as predicted by validated permeation models). Weight loss measurements were undertaken in order to quantify the corrosion rate in these simulated annulus environments and metallography was undertaken to characterise the corrosion and check for HIC/SOHIC.

Corrosion Testing of Reinforcement in Simulated Annulus Environments of Flexible Pipelines

2002 ◽  
Author(s):  
N. J. Underwood
Keyword(s):  
Weight Loss ◽  
Carbon Steel ◽  
Small Scale ◽  
General Corrosion ◽  
Flexible Pipe ◽  
Operational Conditions ◽  
Simulated Environments ◽  
Scale Test ◽  
Test Cells ◽  
Internal Volume

The multi-layered unbonded structure of a flexible pipe creates an inherent internal volume known as an annulus. This annulus envelops the hoop pressure and tensile reinforcements of the pipe. This presents very specific corrosion conditions if seawater intrudes or water condenses in the annulus and no protection system operates to prevent corrosion. This paper describes an investigation into the effect on general corrosion as a result of this environment utilising small-scale test cells. This was undertaken as an attempt to simulate the corrosion conditions that may occur in differing zones of a flexible pipeline. The cell environment was varied by use of both de-ionised water and seawater. The system was saturated with CO2 and CH4 to simulate permeation of this gas through the polymer pressure sheath. Electrochemical and weight loss measurements were undertaken in order to quantify the corrosion rate in these simulated environments. This approach attempts to give useful information regarding the nature of carbon steel tensile reinforcements used in flexible pipeline under operational conditions.

Comparison of 200 Liter and 40 Milliliter Leach Tests

1982 ◽  
Vol 15 ◽  
Author(s):  
J. H. Westsik ◽  
C. O. Harvey ◽  
F. P. Roberts ◽  
W. A. Ross ◽  
R. E. Thornhill
Keyword(s):  
Large Scale ◽  
Deionized Water ◽  
Waste Form ◽  
Small Scale ◽  
Matrix Elements ◽  
Elemental Concentrations ◽  
The Past ◽  
Leach Test ◽  
The Matrix ◽  
Scale Test

ABSTRACTDuring the past year we have conducted a modified MCC-1 leach test on a 145 kg block of a cast cement waste form. The leach vessel was a 200 liter Teflon®-lined drum and contained 97.5 liters of deionized water. The results of this large-scale leach test were compared with the results of standard MCC-1 tests (40 ml) on smaller samples of the same waste form. The ratio of leachate volumes between the large and small scale tests was 2500 and the ratio of sample masses was 150,000. The cast cement samples for both tests contained plutonium-doped incinerator ash.The leachates from these tests were analyzed for both plutonium and the matrix elements. Evaluation of plutonium plateout in the large-scale test indicated that the majority of the plutonium leached from the samples deposits onto vessel walls and little (<3 × 10−12M) remains in solution. Comparison of elemental concentrations in the leachates indicates some differences up to 5X in the concentration in the large- and small-scale tests. The differences are attributed to differences in the solubilities of Ca, Si, and Fe at pH ˜11.5 and at pH ˜12.5. The higher pH observed for the large-scale test is a result of the larger quantities of sodium in the large block of cement.

H2S Consumption and the Derivation of a New Annulus Prediction Model for Offshore Flexible Pipes

2016 ◽  
Author(s):  
Marie Haahr ◽  
Jonas Gudme ◽  
Jacob Sonne ◽  
Sten Overby ◽  
Torben Nielsen ◽  
...  
Keyword(s):  
Prediction Model ◽  
Scale Validation ◽  
Cost Savings ◽  
Small Scale ◽  
Annular Space ◽  
Flexible Pipe ◽  
Independent Verification ◽  
Outer Sheath ◽  
Flexible Pipes ◽  
Sour Service

This paper presents the outcome of investigations on the effects of H2S consumption in the annulus of a flexible pipe. Low-molecular gases, such as CH4, H2S, H2O and CO2, permeate slowly from the bore through the inner liner into the annular space between the inner liner and outer sheath of a flexible pipe. This space is densely packed with carbon steel armour wires leaving a very limited free volume. In the presence of water, a corrosive environment for the armour wires is generated and a risk of sour service cracking is introduced. H2S concentration in the annulus is traditionally calculated by balancing the inflow through inner liner and the outflow through outer sheath and vent valve. In order to assure H2S resistance of the armour wires towards calculated H2S concentrations, pipes for sour service are typically designed with lower strength wire grades of larger dimensions compared to the possibilities of sweet service pipes. Over the last decade, more and more offshore data has been obtained indicating considerably less H2S in the annulus than predicted by the traditional annulus models. This observation has triggered in-depth investigations of the complex corrosive H2S environment inside a flexible pipe annulus exposed to sour service conditions. An extensive small-scale test program has been conducted and showed that at permeation rates typical for flexible pipes, the consumption of H2S in the corrosion processes occurring in the annular space lowers the concentration and hence criticality of the H2S so significantly that it leaves the traditional models overly conservative to an extreme extent. Using this knowledge of consumption of the corrosive gases in the annulus has become an increasingly important topic with the focus on deeper waters, cost savings and service life extensions without compromising flexible pipe integrity. Based on experimental data obtained, a new annulus model for prediction of H2S pressure in annulus has been derived. Data is presented in this paper to illustrate the methodology for an annulus prediction where the consumption of H2S is included. The data presented covers laboratory tests with variations and effects of gas flux, H2S concentration and total pressure. A full-scale validation, led to an Independent Verification Agency certification of the model. With the introduction of this new annulus prediction model, a wider range of wire products becomes available for the pipe designers. Lower weight pipes with stronger armour wires render optimizations for both cost savings and applications at deeper waters possible.

Advanced Finite-Element Modeling for Creep Simulation on Flexible Pipe Pressure Sheath

2016 ◽  
Author(s):  
Jérôme Naturel ◽  
Thomas Epsztein ◽  
Thierry Gavouyère
Keyword(s):  
Finite Element ◽  
Full Range ◽  
Sensitivity Study ◽  
Small Scale ◽  
Main Function ◽  
Flexible Pipe ◽  
Creep Tests ◽  
Additional Information ◽  
Fea Model ◽  
Scale Test

Unbounded Flexible pipe used for offshore fields development are usually composed of different layers of polymer and steel, each layer having a specific function during the product service life. This multi-layer characteristic enables to tailor the cross-section of the pipe to meet project-specific requirement, and optimize the cost of the product for each application. In particular, the main function of the thermoplastic pressure sheath is to guaranty the sealing of the product. The material and the thickness of this pressure sheath mainly depend on the pressure and temperature of the bore, and the design choice is driven by the creeping of the sheath in the interstices of the pressure vault: it must be limited with regard to sheath thickness reduction, as per API17J design requirement. Consequently, when developing new material for pressure sheath application, the early prediction of the creep performance over the full range of the targeted application is crucial. For this reason, before any full-scale test, a test campaign is required to evaluate the creeping of the material on small-scale material sample. In this development context, the use of advanced finite-element simulation for predicting the creeping behavior is quite useful to amplify the benefit of tests campaign results, and to give additional information on material performances. As far as the modelling is validated by correlation with small-scale tests, the numerical tool is used to multiply virtual creep tests configurations. This paper will focus on the numerical challenges for developing such creeping simulation, based on ABAQUS commercial software. Firstly, the identification of the viscoelastoplastic parameters for polymer material law will be presented. This material law is a nonlinear viscoelastoplastic model consisting of multiple networks connected in parallel. The number of parameters of such law is not limited, but a compromise between law precision and identification robustness must be found. Then, the correlation process between small-scale test and finite-element results will be detailed. In particular, the influence of the experimental protocol has to be determined. Finally, a sensitivity study of the most influent parameters, based on parametric FEA model, will be presented to highlight the benefice of such model. The benefice of such model does not only consist on correlation with small-scale test. As the material modeling is intrinsic, it is also possible to use the same law for studying the creep behavior on very different geometrical configurations.

Gas and Water Permeation in Flexible Pipes

2002 ◽  
Author(s):  
Tore Roberg Andersen ◽  
Jan Ivar Skar
Keyword(s):  
Large Scale ◽  
Cold Water ◽  
Small Scale ◽  
Test Results ◽  
Test Program ◽  
Flexible Pipe ◽  
Water Permeation ◽  
Flexible Pipes ◽  
Scale Test ◽  
Temperature And Pressure

A test program has been performed to obtain the permeation coefficients for methane, carbon dioxide and water in PVDF. Small-scale tests showed that water is transported through the PVDF inner sheath of the flexible pipes, and into the annulus. A large-scale test was carried out to verify the small-scale test results. It was performed in a 2″ flexible pipe with length 3 m. The bore temperature and pressure were 100°C and 50 bar, respectively. The pipe was submerged in cold water in order to get a correct temperature gradient in the pipe. The test showed that the annulus of flexible pipe with PVDF inner sheath would become water wet due to permeation, depending upon the bore and annulus conditions.

Study of Multiaspect and Multistatic Sonar Systems Using a Small-Scale Test Bed

2010 ◽  
Author(s):  
Jon La Follett ◽  
John Stroud ◽  
Pat Malvoso ◽  
Joseph Lopes ◽  
Raymond Lim ◽  
...  
Keyword(s):  
Small Scale ◽  
Test Bed ◽  
Sonar Systems ◽  
Scale Test

scholarly journals A Novel Niosome-Encapsulated Essential Oil Formulation to Prevent Aspergillus flavus Growth and Aflatoxin Contamination of Maize Grains During Storage

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 646 ◽  
Author(s):  
García-Díaz ◽  
Patiño ◽  
Vázquez ◽  
Gil-Serna
Keyword(s):  
Aspergillus Flavus ◽  
Fungal Growth ◽  
Storage Conditions ◽  
Aflatoxin Contamination ◽  
Small Scale ◽  
Low Concentrations ◽  
Oil Formulation ◽  
Scale Test ◽  
Encapsulation Method

Aflatoxin (AF) contamination of maize is a major concern for food safety. The use of chemical fungicides is controversial, and it is necessary to develop new effective methods to control Aspergillus flavus growth and, therefore, to avoid the presence of AFs in grains. In this work, we tested in vitro the effect of six essential oils (EOs) extracted from aromatic plants. We selected those from Satureja montana and Origanum virens because they show high levels of antifungal and antitoxigenic activity at low concentrations against A. flavus. EOs are highly volatile compounds and we have developed a new niosome-based encapsulation method to extend their shelf life and activity. These new formulations have been successfully applied to reduce fungal growth and AF accumulation in maize grains in a small-scale test, as well as placing the maize into polypropylene woven bags to simulate common storage conditions. In this latter case, the antifungal properties lasted up to 75 days after the first application.

scholarly journals On the Relationship between Low Latitude Scintillation Onset and Sunset Terminator over Africa

2021 ◽  
Vol 13 (11) ◽  
pp. 2087
Author(s):  
Mogese Wassaie Mersha ◽  
Elias Lewi ◽  
Norbert Jakowski ◽  
Volker Wilken ◽  
Jens Berdermann ◽  
...  
Keyword(s):  
Moving Boundary ◽  
Occurrence Rate ◽  
Scintillation Index ◽  
Small Scale ◽  
Bahir Dar ◽  
Remarkable Change ◽  
Equatorial Africa ◽  
Night Side ◽  
Solar Terminator ◽  
First Time

The solar terminator is a moving boundary between day-side and night-side regions on the Earth, which is a substantial source of perturbations in the ionosphere. In the vicinity of the solar terminator, essential parameters like S4 index measurements are widely analyzed in order to monitor and predict perturbations in the ionosphere. The utilization of the scintillation index S4 is a well-accepted approach to describe the amplitude/intensity fluctuation of a received signal, predominantly caused by small-scale irregularities of the ionospheric plasma. We report on the longitudinal daily and seasonal occurrence of GNSS signal scintillations, using the data derived from the GNSS stations in Bahir Dar, Ethiopia, Lomé, Togo and Dakar, Senegal. The observed seasonal climatology of GNSS signal scintillations in equatorial Africa is adequately explained by the alignment of the solar terminator and local geomagnetic declination line. It should be pointed out that the strongest scintillations are most frequently observed during the time when the solar terminator is best aligned with the geomagnetic declination line. At all three stations, the comparison of computational and observational results indicated that the scintillation activity culminated around equinoxes in the years 2014, 2015 and 2016. Comparatively, the western equatorial Africa sector has the most intense, longest-lasting, and highest scintillation occurrence rate in equinoctial seasons in all three years. For the first time, we show that the seasonal variation of the scintillation peaks changes systematically from west to east at equatorial GNSS stations over Africa. A detailed analysis of the solar day–night terminator azimuth at ionospheric heights including the time equation shows that the scintillation intensity has a maximum if the azimuth of the terminator coincides with the declination line of the geomagnetic field. Due to the remarkable change of the declination by about 10° at the considered GNSS stations, the distance between scintillation peaks increases by 46 days when moving westward from the Bahir Dar to the Dakar GNSS station. The observations agree quite well with the computational results, thus confirming Tsunoda’s theory.

BLISS@CNR-Pisa: a flexible laser for small scale test experiments on fusion oriented physics

2010 ◽  
Author(s):  
O. Ciricosta ◽  
L. Labate ◽  
S. Atzeni ◽  
A. Barbini ◽  
D. Batani ◽  
...  
Keyword(s):  
Small Scale ◽  
Scale Test

scholarly journals Nucleation in continuous flow cooling sonocrystallization for coiled capillary crystallizers

2021 ◽  
Author(s):  
Mira Schmalenberg ◽  
Lena K. Weick ◽  
Norbert Kockmann
Keyword(s):  
Time Distribution ◽  
Residence Time Distribution ◽  
Flow Cell ◽  
Deionized Water ◽  
Small Scale ◽  
Non Invasive ◽  
Ultrasonic Bath ◽  
Continuous Crystallization ◽  
Wide Range ◽  
Inner Diameter

AbstractNucleation in continuously operated capillary coiled cooling crystallizers is experimentally investigated under the influence of ultrasound. It was found that there is no sharp boundary but rather a transition zone for nucleation under sonication. For this purpose, a tube with an inner diameter of 1.6 mm and a length of 6 m was winded in a coiled flow inverter (CFI) design and immersed into a cooled ultrasonic bath (37 kHz). The CFI design was chosen for improved radial mixing and narrow residence time distribution, which is also investigated. Amino acid l-alanine dissolved in deionized water is employed in a supersaturation range of 1.10 to 1.46 under quiet and sonicated conditions. Nucleation is non-invasive detected using a flow cell equipped with a microscope and camera. Graphical abstract Since the interest and demand for small-scale, continuous crystallization increases, seed crystals were generated in a coiled tube via sonication and optically investigated and characterized. No distinct threshold for nucleation could be determined in a wide range of supersaturations of l-alanine in water

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