The Kem One plant in Lavéra is using the brine pipeline to produce sodium carbonate, hydrogen and sodium hypochlorite from chlorine. The sodium chloride concentration in the transported fluid amounts to 300 grams per litre completely dissolved in water. The plant in the south of France near Marseille is the source of 25% of French chlorine production and 40% of French VCM (vinyl chloride monomer) production. The DN 450 steel pipe concerned is regularly inspected with ILI tools to assess the condition of the pipe. In 2018, the pipeline operator identified the need to perform preventative maintenance on a section with 455 m, running underneath a channel with four sweeping bends of 45 degrees and a definition of r = 33 x D each.
The client had the choice to install a new steel pipe using HDD or rehabilitate the existing pipe using Primus Line®, a Kevlar®-reinforced no-dig relining solution. A comparison study was performed by engineering consultant Eureteq specialized in French and international project management for transmission pipelines and in technical and regulatory consulting. The study came to the conclusion that significant cost savings were feasible using the Primus Line® system in addition to an essential reduction of time required to execute the project. Furthermore, using the Primus Line® system eliminates corrosion. The project was realised by two Primus Line partners: Altero Travaux Publics as general contractor and Danphix S.p.A. as their subcontractor.
During factory acceptance testing, a burst pressure test was conducted on the produced DN 400 high pressure liner as well as the connector. The test results showed a burst pressure of the liner of 92 bar. The connectors were successfully tested with 115.5 bar. Long term tests according to DVGW VP 643 and ISO 9080 determined a fabric factor of 2.0 to achieve a 50-year life span. In addition, a safety factor of 1.25 is incorporated. Hence, the pipeline can be safely operated with 28 bar. The liner’s PE inner coating is suitable for the transport of brine.
In preparation of the Primus Line® system’s installation, a by-pass was created to guarantee the supply of brine during the renovation time. In a first step, the pipe was CCTV inspected to assess the condition of the host pipe. The contractor performed mechanical cleaning of the host pipe using rubber pigs. The 455 m of liner were delivered pre-folded into U-shape on a transport reel directly to the site. A pulling head was mounted to the start of the liner and connected to a rotation joint and subsequently to the cable of a pulling winch.
The liner could be installed in less than one hour and was re-rounded using compressed air. The end fittings equipped with DIN flanges PN 40 were mounted. The renovated section was successfully pressure-tested using brine with 34.5 bar. The void between the liner and the host pipe was filled with nitrogen to monitor the annulus space. The whole installation of the Primus Line® system was completed within one week. This rehabilitation extended the life of the existing asset by at least 50 years.