Technical Presentations at the April 2010 Meeting

1.1  Material Testing in Super Critical CO2 Environments’, Matthew Peet, CAPCIS

Capture of CO2 from fossil fuel is currently very expensive (~£90/T-) but there are drives during 2010-2020 (particularly in the UK)  to reduce this to £30-£50/T, which would make the technology more viable.  Experience of handling CO2 transport has been gained through enhanced oil recovery techniques and 13,000 wells with 13,000 miles of high pressure CO2 pipelines are currently operating successfully.  No significant corrosion issues have been experienced with this technology, although the water content of the CO2 used is generally <500ppm.   

Regarding CCS, the main issues with its development are: characterisation of the CO2 involved (including composition), properties of proposed storage sites, the potential leakage rates and the transportation infrastructure.  Results are presented showing  testing carried out at CAPCIS on carbon steel and corrosion resistant alloys (CRAs) in supercritical CO2 for 6 months. The CO2 environment was modified through the addition of water and H2S.  Decompression testing was used to determine the effects of such environments on a number of polymers.  The presence of water in the CO2 was found to greatly increase the corrosion rate of carbon steel (corrosion rates around 20mm/y being determined) and polymer coatings were found to lose strength due to hydrolysis. However, CRAs were found to show good corrosion resistance.  CT

 

3.1  Computer Modelling in the Design and Operation of Oil & Gas Fields and its Role in Effective Asset Management’, Robert A Adey, CM BEASY Ltd

 CP System designers and operators are frequently presented with challenges to extend the life of offshore structures, develop new systems to protect deepwater developments and provide innovative solutions to new forms of energy devices such as wind farms.  Designing the cathodic protection [CP] systems is problematic without an appreciation as to how CP systems fitted to the various components will interact with one another once the entire asset is commissioned and how this will impact the protection provided to the individual components and the degree of corrosion control over the life of the structure.  This presentation will describe how computer modelling can be used to provide answers to these questions during both the design phase and as an aid to predictive planning during the operation of the asset.

For a recent deep-water project, a computer modelling study was commissioned to provide information on the performance of the CP systems protecting each of the subsea structures and in particular the interaction currents flowing between them.  The principal aim was to ensure that the impressed current CP (ICCP) system on the hull of the FPSO would be operated in such a manner as to reduce interaction with the sub sea sacrificial anode CP (SACP) systems to the minimum possible throughout the operating life of the field and to develop an understanding of the probable behaviour of CP systems on the key components (FPSO, Oil offloading lines & Buoy, Riser Structures, etc.) particularly in respect of sacrificial anode lives.

The model has been also used to aid future planning as CP monitoring data has become available from the ICCP system and ROV surveys to verify the system is performing as per the design assumptions.  The intention is to further refine and develop the model as a working tool that will be used to provide input to Risk Based Inspection and maintenance planning and interpret information from surveys.

Information is now available from surveys carried out on the structure and the presentation compares the model predictions with the measured data.  The presentation described the strategy and rationale behind the modelling studies and some of the major lessons learned from the comparisons. 

[Contact: Dr Robert A Adey  C M BEASY Ltd, Ashurst Lodge, Ashurst, Southampton, SO40 7AA  www.beasy.com].

A pdf version of this presentation has kindly been provided for staff of MCF member companies – please contact the Secretariat for a copy  

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3.2   Modern Surface Analysis Techniques and their Possible Application to Corrosion Issues’, John Sullivan, Midlands Surface Analysis, Aston University

It is estimated that corrosion in industrialised nations can costs between 3 and 5 % of GDP per year, thus reduction or elimination of corrosion has the potential to save vast amounts of money.

Under normal circumstances corrosion begins and terminates at very thin layers at a surface, when a protective or passivating surface oxide film breaks down allowing contact between the active metal and invading molecular species. To eliminate or at least alleviate the effects of corrosion it is necessary to understand the controlling processes and this can only be done by developing an understanding of interactions within the first few atomic layers of a surface. This understanding may only be achieved by the use of modern surface analytical techniques. It is explained that traditionally used methods, such as, electron microscopy, EDX/ EDXS/ EDAX and XRD based techniques are not surface specific and will not provide the chemical information required to solve the problems.

In this presentation the most important and relevant surface analytical techniques are discussed in order of importance. These are X-ray Photoelectron Spectroscopy (XPS), Auger Electron Spectroscopy (AES) and Secondary Ion Mass Spectrometry (SIMS). The principles of these techniques are briefly discussed as is the information relevant to corrosion investigations that can be gained from each technique.

Several case studies are shown where the above techniques have been used to solve corrosion related and surface coating failure problems.  [Contact: Professor John Sullivan, Midlands Surface Analysis, SEAS, Aston University, 0121 204 3532, j.l.sullivan@aston.ac.uk, www.midsurfanalysis.co.uk ]

A pdf version of this presentation has kindly been provided for staff of MCF member companies – please contact the Secretariat for a copy

 

3.3    

The Real Cost of Corrosion’, Chris Fowler, Exova and President of NACE International

 The estimated worldwide direct cost of corrosion exceeds $2.1 trillion (>3%GDP), but money is only one of the real costs.  Others highlighted included:  

q       The use of cooking pots in the third world which are made of a metal composition, of aluminium-containing scrap from parts of cars, drinking cans, tins and tubes, and which easily corrodes from a reaction with the cooked food, seriously impairing health.

q       Interstate 35-Minnesota Bridge collapse in Minneapolis. 

q       Water, a precious commodity, >25% wasted. 

q       Corrosion of steel-reinforced concrete piles in the splash zone.

q       Corrosion of  pipelines running close to habitation.

The work of the World Corrosion Organisation was explained, along with its goals.  The WCO has applied to the United Nations for NGO status, and has the intention to bring Governmental awareness to the cost of corrosion and stimulate R&D funding.  

Future major areas of Research include the areas of Nuclear plants, Transportation and Carbon Capture.  

To satisfy the basic needs of the 6.3 billion people on this globe, including proper nutrition, clean water, good health, safe housing, dependable energy, effective communication, and mobility, many technological changes with global dimensions must be accomplished. While this concept is widely appreciated as such, there is often only a limited awareness of how critical it is to solve corrosion problems and what the real implications are to society.  

A pdf version of this presentation has kindly been provided for staff of MCF member companies – please contact the Secretariat for a copy. 

 

3.4 ‘Numerical Simulations for Design and Monitoring of Offshore Structures’ ICCP Systems’, Jacques Parlongue, Elsyca, Belgium

Design considerations for cathodic protection systems of seawater applications have been changing in the past 20 years, because Impressed Current Cathodic Protection (ICCP) systems have made a big development in the last decades. Nowadays ICCP systems offer a lot of monitoring and control features. Today a gradual shift from sacrificial anode systems to Impressed Current Cathodic Protection (ICCP) systems can therefore be recognized.  From a general point of view ICCP systems are better performing than sacrificial anode systems, but the performance is strongly dependent on the number of anodes and rectifiers being used, thereby impacting heavily on the total installation cost of the ICCP system.  A computer aided ICCP system design allows optimization of the performance of the ICCP system while keeping the total number of anodes and rectifiers as limited as possible.

The paper presented described an ICCP system that was applied for the first time to a bare steel offshore platform. Computer modeling simulations for predicting the local protection level on the submerged surfaces of this structure have enabled the design of an optimized ICCP system configuration that was successfully installed into the field.

This presentation described the performance of an intermediate design stage of the ICCP system as predicted from the computer simulations and discussed the specifics of the simulation method.  It was demonstrated that the computer simulation results can provide an indication on how to improve the ICCP system design.  [Contact: Jacques.parlongue@elsyca.com]

A pdf version of this presentation has kindly been provided for staff of MCF member companies – please contact the Secretariat for a copy.

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