TPI April 2009

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Pipel ine productsOCTG goods and
48 Tube Products International April 2009
hardness, roughness, pull off and
impact performance. Polyurethane is
used as insulation on pipelines, for
example subsea. Dow Hyperlast has
new technology to reduce weight by
8% and improve thermal properties by
12.5%. Interface bonding, with the use
of primers, can increase pull strength to
10 MPa.
In the Northern hemisphere current
Borealis Borcoat PE meets the
challenges from -50° to +85°C. The
Southern hemisphere requires a range
from -30° to +90°C, with outstanding
UV and mechanical resistance. The
new Borcoat HE3450-H meets these
demands. A new PE adhesive has been
developed by LyondellBasell to improve
bonding and widen the application
window (it can be used in induction
coil and flame heating systems). The
company also has a top coat resin
from multimodal HDPE with high safety
margins.
EUPEChasbeenexaminingPP insulation
coatings and field joints. In water depths
up to 500m a system of FBE, adhesive
PP, solid PP, foamed PP and solid PP
is used. For 3,000m more layers are
required, for example a 7-layer system
involving FBE, adhesive PP, solid PP
and syntactic PP (with hollow glass
microspheres). Joint systems include
injection moulded PP (IMPP).
Arkema has 40 years of experience
with oilfield applications of polyamide
11. It has been used as a barrier layer
in offshore flexible pipes, as a liner for
sour gas, in gas pipelines in Australia for
35 years, in desalination plants, water
and wastewater treatment plant pipes.
The pipe surface must be prepared and
primed and the polyamide layer ranges
from 100 microns to several millimetres
thickness. Evonik is another supplier to
the industry and has looked at materials
for rotational sintering, used in pipe
lining. It produces polyamide 12 and
PEEK which are very high performance
polymers. PEEK can be used at
temperatures up to 300°C and has high
abrasion and chemical resistance.
Bandera has developed machinery
to reduce the use of polymer in pipe
coating. Pipes are never completely
straight so extra coating is used up
where the pipe bends. Sensors are used
Market and technical trends in steel pipe coating
The pipeline coating market expanded
from 120 million m2 in 2004 to 190 million
m2 in 2007, with a global annual growth
rate of 15%, according to research
conducted by Noru Tsalic at Applied
Market Information.
Polyethylene (PE) accounts for the
majority of the market for polymers (over
350 kt), followed by polypropylene (PP)
and epoxy (FBE). Asphalt is still used
but generally now in more specialised
applications such as under impinged
concrete. Concrete is also used as
a coating, for example for weight in
negative buoyancy applications. The
challenges for pipeline engineers are the
increasingly aggressive contents and
the harsher operating conditions for oil
and gas. Cathodic protection is limited
by the amount of current required,
hence the need for coatings. This was
discussed at the January 2009 AMI
conference on Pipeline Coating, held
in Vienna, Austria. Bredero Shaw and
Shawcor are leaders in the field of pipe
coating. Graded structure coatings were
developed in the 1990s and comprise
an FBE layer covered by an adhesive
layer and a polyolefin. The FBE gives
excellent adhesion to steel and the
polyolefin provides a moisture barrier.
The traditional multilayer PE application
process can lead to a tenting effect in
the weld region. The company’s new
technology overcomes this, and the
outer layer provides enhanced resistance
to damage.
Denis Melot of Total outlined the
company’scurrentresearchandpractice:
3-layer PE is used up to operating
temperatures of 80°C and 3-layer PP is
used over 80°C and offshore, with heat
shrink sleeves for field joints. There have
been problems worldwide with coating
disbondment, and Total is looking to
remedy the situation.
In Brazil, Andre Koebsch of Petrobras
has worked with pre-qualification testing
(PQT) of FBE coated pipeline. The pipe
is checked for areas of disbondment,
coating thickness, gouge resistance,
Brushes for weld cleaning
Osborn International manufactures
brushes and abrasives for use in the
industrial, trade and private sector. Steel
wire brushes are an ideal solution for
the cleaning of welded seams. They are
a cost effective and practical method
for removing welding cinder and beads
that prevent the next seam from being
applied. The use of cellulose and alkaline
electrodes are insignificant, as a brush
will carefully remove all types of cinder.
A rotating wire brush will provide a clean
welded seam without having to remove
up to 30% of the welding material, as is
inevitable with a grinding disc.
Any defects in the weld seam also
become immediately visible, enabling
any rework to be carried out promptly.
The use of steel wire brushes reduces the number of seams by a claimed
30-50%, and additional time needed for resoldering work can be avoided.
Whether weld cleaning, internal or external cleaning, bevel end cleaning,
removal of insulation coats or rehabilitation work, Osborn pipeline brushes
promise long life, optimal brushing results and safe work.
Osborn International GmbH – Germany
Cleaning a welded seam using a S S
rotating wire brush