High pressure transmission pipeline of natural gas tee reinforcement

Transmission pipelines are widespread. Most of these pipelines you are not aware of, because they are located underground or at the bottom of the sea. Gas and Oil are typical media transported via transmission pipelines. It is crucial to keep these lines in perfect condition as many times high pressure is involved. This infrastructure also includes block valve stations (BVS) at certain distances. Equipment located in these stations need good maintenance. Inspection discovered welded joints on the gas transmission pipeline did show a high-level degradation. Immediate action was required.

Challenge

The repair challenge in this case was to strengthen the affected weld of a reducing tee (from 18- to 2-inch) at a pressure close to 100 bar. Wrapping a normal tee already is a job that needs to be performed by a trained installer. Wrapping a tee with this large difference in diameter requires even more skills. Together with the client we have designed a flower wrap. This case study will provide you with some inside.

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Additional reinforcement of the pipeline diameter of DN530 mm

The operator of the high-pressure crude oil pipeline requested additional protection due to the planned construction of a motorway above this 20-inch line. The pipeline should be strengthened for a length of 40-meters.

Challenge

Wrapping a pipeline of such a diameter for 40 meters is a job that requires good organization. A blasted and clean surface of the pipeline should be wrapped as soon as possible to avoid flash rust. Irregular surfaces will be treated by a Putty, a compressive modulus filler, followed by applying the Primer for an optimal adhesion between the wrap and the pipeline. The process of mixing and setting of these two-component epoxies is irreversible. The surface still needs to be a bit sticky when the impregnated carbon cloth is wrapped around the pipe. The whole process should be performed in steps and the team leader should keep all crew members busy during the installation.

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Leak repair and pipeline reinforcement at girth weld of DN700 mm oil pipeline

The pipeline operator detected a leak at the girth weld of a carbon steel pipeline operating at working pressure 16 bar. The damaged weld is on an elbow with a reduction from a diameter of 28-inch to 20-inch (reducer).

Challenge

Composite repair materials cannot be installed directly over the leaking pipe. Leaks need to be stopped always before moving on. This case study describes how to stop the leak. Second challenge was the geometry of the wrapping area. Using different width carbon cloth almost every geometry can be wrapped, like in this case the reducer section of the line.

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Repairing dents in an underground carbon-steel pipeline

Dents in transmission pipelines are a common problem that need to be fixed as soon as possible. Dents will make the pipeline in that particular area weaker. There is a chance of crack forming or even creation of a hole if the dents are not properly repaired. CTE BV is working with epoxy composites and carbon fiber cloth to save repair the pipeline. Compressive Modular Filler (CMF) is applied to bring back the dent area in it’s normal shape. The carbon fiber cloth in combination with epoxy composites will bring back the integrity of the pipe after curing. The case study explains how to approach a dent defect in your pipeline. The repair is performed according the standard ISO 24817.

Challenge

The repair has to take place under pressure to push out the dent as much as possible before applying the CMF putty and carbon fiber wrap. Often natural gas pipelines are buried and access is only allowed when the installer did receive a confined space training.

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Repairing a carbon-steel pipeline 11 meters above the ground

Repairing a tee using composites needs a special training program. During Level-1 training courses applied by CTE BV applicants will be trained according ISO 24817 and/or ASME PCC-2 standards. If applied correctly the number of layers over the defected area should count 4-8 layers. In this case one of the girth welds needed to be strengthen by applying a carbon fiber and epoxy composite repair. This operation is a very common activity that trained installers perform daily.

Challenge

The particular challenge in this case was working at height and with a High Temperature solution. Access to the repair area was complicated due to the lack of being able to bring in aerial platform equipment. Scaffolding was the only possibility for the installers to save repair the tee. Although the cost for scaffolding and other safety precautions did increase operational costs, the composite repair was preferred above replacing this part of the pipe. Finally the high ROI (Return on Investment) did decide management to carry out the repair.

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Extending the lifetime of a pipeline with ten years in 48 hours

Flare lines at refineries often suffer from corrosion. These lines are crucial for the refinery as these systems are used for safe disposal of waste gases by burning them under controlled conditions. Imagine the mixture of chemistry these lines face. Very susceptible for corrosion attacks, mainly internally but also external. The often high temperatures of the medium also accelerate corrosion. Blasting, cleaning and wrapping the lines by applying composite materials is a way to extend the lifetime. Composite materials have strong capabilities and it’s a durable and environmentally accepted method for repair. The engineered repair applied can withstand a 100% wall loss situation of a certain diameter.

Challenge

In this particular case blasting the pipe was not an option. The crew had to roughen and clean the flare line sections by hand(tools). In many instances a Bristle Blaster® of Monti may be the solution. Surface preparation is a key part of a successful wrapping project.

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Repairing a massive carbon steel pipe within 24 hours

A small leak under a metal sleeve at a 28” pipe is a problem and requests a fast and proper solution. The size of the sleeve basically would be considered as the defected area which required a repair of a reasonable size. By dropping the pressure in the pipeline the small leak was stopped and contained. Immediately after the leak was stopped the engineered carbon fiber epoxy based system was applied covering the sleeve and surrounding pipe area. The multi-layer carbon fiber solution will last for many years.

Challenge

The timeframe between starting preparation of the 100 kg repair kit, shipping from the Netherlands to Croatia, installing the wrap and curing of the epoxy was roughly 24 hours.

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Carbontech Composites certifies its carbon fiber wrap system Revowrap

Carbon Tech Europe BV proudly announce the certification by TUV of the Carbon Composite Repair Programs Revowrap110™, Revowrap185™ and Revowrap225™. This certificates’ scope include but is not limited to the Gas & Oil Industry, Power Plants, Mining and Transmission Pipelines. With this step we make the wrap program even more complete. We are ready to help our clients in Europe, Earasia and Northern Africa.

Check our TUV ISO 24817 Certificate

Repairing an active leak at a natural gas carbon steel pipeline

An active leak in a natural gas transmission pipeline is a nightmare for every gas distributor. It creates an environmental undesirable and dangerous situation that needs to be fixed as soon as possible. Stopping the leak was the first step in the process of repairing the pipeline. In this case the girth welds of the pipe were showing weak points and in one particular case there was a small leak. After the leak was stopped by using a low-profile leak sealing solution provided by CTE BV the engineered carbon fiber epoxy based system was wrapped around the repaired area. The particular area was secured for future leakages.

Challenge

Besides stopping an active leak also the winter circumstances did ask for a professional approach towards a successful repair according ISO 24817.

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