Technical Presentations at the January 2009 Meeting
InfiniteFocus system is ideal for the study of the effects of all types of
corrosion and engineered surfaces. It
is now in use in many corrosion laboratories around the world.
operating principle is Focus Variation.
This moves the focus plane of a known objective lens vertically
over a surface which in conjunction with Smartflash illumination builds up
a 3D full colour model of the surface to be examined.
areas up to 100mm square can also be imaged using the built in X-Y stage,
artefacts that can be caused by multiple imaging are avoided by the
alignment of the 3D data points as opposed to stitching.
The resultant 3D model can then be used to measure features on the
surface of the object.
Measurement Capabilities include
these measuring tools enables quantification of corrosion damage with high
resolution visualisation permitting examination of features such as crack
viewable image is made up of 3D data points that can also be exported into
other 3D analysis packages for further investigation.
Contact: Brian Kyte,
Alicona Uk Ltd, Lime Tree House, 15 Lime Tree Walk, Sevenoaks TN13 1YH, [email protected],
tel: 07984596015, www.alicona.com
The presentation gave an
introduction to the Cathelco Group Companies compromising:- Cathelco,
Cathelco Jotun, Corrintec, MPSL, F.A.Hughes, Wilson Taylor and Morgan
The next section highlighted the problems of corrosion and the need for corrosion control of submerged hulls. The principles of ICCP and Sacrificial anodes were then covered including the arrangement of an ICCP system and detailed description of all the components of the ICCP system.
Further types of ICCP system were also introduced including systems for Bow and Stern thruster Tunnels, Aluminium Hulls and Aluminium Waterjets, summarised by a list of advantages of ICCP systems over Sacrificial anodes.
On Antifouling systems the problem of bio-fouling was discussed including the bio-fouling sequence and the problems, maintenance requirements caused by marine growth within pipework systems. The Cathelco copper dosing Anti-fouling system was then introduced with an explanation of the process and the components required.
In summary, ICCP systems in conjunction with coating systems:-
q Totally prevent hull corrosion
q Are cost effective
q Are low maintenance
Marine pipework Anti-fouling systems:-
q Prevent blockages and restrictions
q Make major savings in pipework maintenance and renewal costs
q Prevent engines from overheating and reduce fuel usage
Contact: Steve Ellis, Cathelco
Corrintec, Marine House, 18 Hipper Street South, Chesterfield S40 1SS,
Tel: +44 1246 246700, [email protected], www.corrintec.co.uk
investigation of the behaviour of 70/30 copper-nickel tube alloy under
conditions of sulphide exposure was undertaken after occurrences of rapid
pitting corrosion in naval seawater cooled heat exchangers, believed to
have been induced by microbial sulphide generation.
response of copper-nickel alloy surfaces to various pre-conditioning
practices prior to exposure to seawater was studied, covering short
chemical pre-treatments using sodium dimethyl-dithiocarbamate (SDD),
benzotriazole (BTA) or ferrous sulphate solutions and longer term
conditioning with static or flowing freshwater or clean seawater.
The experimental programme used the Linear Polarisation Resistance
method supported by mass loss measurements to determine the resistance of
copper-nickel pre-conditioning surface films towards corrosion induced by
the high localised levels of sulphide believed to be induced by microbial
It was found that none of the pre-conditioning treatments employed provided immunity to corrosion due to high levels of sulphide in seawater, but that some treatments did improve or accelerate the formation of corrosion protective films on 70/30 copper-nickel alloy surfaces when subsequently exposed to sulphide-free seawater.
of Interactions Between Impressed Current and Sacrificial Anode Cathodic
Protection Systems in Offshore Installations’, Robin Jacob,
Corrosion Consultancy & Cristina Peratta & John Baynham, CM BEASY
Recent oil and gas developments have involved
operations in deep waters, with installation depths greater than 2000 m
becoming commonplace. For
such developments, the most practical approach has been to use a floating
production storage and offloading [FPSO] system, with produced fluids
transferred from the well heads through manifolds, flow lines and a riser
system to the FPSO. Designing
Cathodic protection [CP] systems to protect the individual components of
such a development can be problematic without an appreciation as to how
they will interact once the entire asset is commissioned.
This is particularly true where impressed current [ICCP] systems
are fitted to the FPSO hull, with sacrificial anodes on the subsea
equipment. It can also be further complicated where responsibility for the
various structures lies with different parties.
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 components and in particular the interaction currents flowing
between the FPSO and the riser system.
The principal aim was to ensure that the ICCP system on the hull of
the FPSO could be operated in such a manner as to reduce interaction with
the sub sea sacrificial anodes to a minimum throughout the operating life
of the field. As CP
monitoring data becomes available from the field, the model will be
further refined and developed as a working tool for the field Operations
group to utilize as input to Risk Based Inspection and maintenance
presentation describes the strategy and rationale behind the modelling
programme and some of the major lessons learned.