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Polyurethane solutions for the pipeline industry |
Polyurethane and other foams
Polyurethane solutions for the pipeline industry
Presented by Dr. Stefan Quaiser, European Sales Manager for coatings, adhesives, sealants, elastomers and specialities, Elastogran GmbH, Olching
Trade Press Conference K 2004, June 22, 2004, Ludwigshafen, Germany
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Pipelines are an essential means of transporting oil and gas, and often stretch for hundreds of kilometres, in sometimes extremely hostile environments. Not surprisingly, the engineering requirements - designed to prevent corrosion and leakage - are correspondingly high (figure 1).
Polyurethane (PU) is nowadays a standard coating material for pipelines thanks to its ability to reinforce, insulate and protect against corrosion. Elastogran, the leading European supplier of PU systems to the oil and gas industry, has been an early player in the development of engineering solutions for oil and gas transmission. The company now offers a new three-product package for laying pipelines on land and at sea (figure 2).
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Fast coating of welds and pipe sleeves: Elastocoat C 6830
The new coating and casting compound Elastocoat® C 6830 provides pipelines with permanent protection irrespective of whether laid on land or at sea. Elastocoat C 6830 in particular enables an effective wear-resistant, anti-corrosion layer to be applied quickly and economically to the pipe joints and connecting sleeves. The hardness, density and curing time of Elastocoat can be individually matched to the conditions at the job site (figure 3).
One common method of pipe laying is microtunneling, in which the pipes are pushed into a bored tunnel as opposed to being laid in an open trench. The pipe itself is encased in a concrete jacket. As the pipe is being installed, the connecting sleeves and centering rings are subjected to high tensile stress - which places special demands on the mechanical stability and abrasion resistance of the insulation material (figure 4).
The ease with which the casting compound can be handled and applied is a real advantage, especially on-board pipe-laying ships. Here, the individual pipe sections are first joined and the welds cleaned and sand-blasted. If necessary a thin coat of PU primer is applied to the prepared area. A casting form is next placed around the connecting sleeve and filled with polyurethane. Elastocoat systems provide extremely short curing times so that after just a few minutes the form can be removed and the pipe section is ready to be submerged.
Elastocoat C 6830 was also used to coat the protective anodes fitted to a 400 km gas pipeline running between Libya and Italy.
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Keeping warm under water: The proven Elastopor H and the new Elastoshore 2570
Polyurethanes for offshore use not only have to protect metal by excluding sea-water and air, they must themselves be stable to hydrolysis, absorb very little water and adhere well to steel. Of particular importance however is quick, easy and reliable processing in the cramped environment on board ship, as well as in icy and tropical conditions (figure 5).
Elastopor H
Special rigid foams are used for insulating pipes laid at sea. The insulation is necessary to keep the oil at a pumpable viscosity by minimizing heat loss from the pipe. Together with a customer, Elastogran developed a special high-compression variant of Elastopor® H for use at depths of up to 200 metres (figure 6).
Elastoshore 2570
The tapping of ultra-deep offshore oil required the development of foams able to withstand enormous pressures. At depths of 3,000 metres, "shallow-water" foams would simply collapse. The required compressive strength was achieved by incorporating microscopic glass beads into a solid PU elastomer matrix. The thermal insulation properties are due to the vacuum within the glass beads. The resulting foam/glass-bead composite is practically incompressible; even several thousand metres of water pressure fail to distort its structure. The name of this special material is Elastoshore® 2570 and completes Elastogran's product portfolio for the pipeline industry (figure 7).
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