Abstract
Thermoplastic liners for pipelines have emerged as an effective solution for protecting pipeline assets from internal corrosion, significantly reducing the life cycle cost.
High Density Polyethylene (HDPE) and Polyethylene Raised Temperature (PE-RT) are the most widely used materials in thermoplastic lining for water applications. Their favorable properties, availability, and cost-effectiveness contribute to their popularity. However, like all polymers, HDPE and PE-RT are susceptible to permeation, particularly when interacting with fluids or gases with smaller molecular sizes.
Factors such as fluid composition, pressure, and temperature will have an impact on the rate of permeation. When fluids or gases migrate between the polymer liner and the steel substrate, they can lead to pressure build-up and compromised integrity of the lining system.
The emergence of innovations in thermoplastic raw materials in thermoplastic lining technology and thermoplastic raw materials provided an opportunity to explore the possibility of extending the application envelope to highly demanding applications such as pipelines with hydrocarbon service CS fittings
The safety liner system addresses these challenges by incorporating a unique design that includes external grooves on the outer surface of the liner. These grooves provide a designated space for accumulating fluids and gases, thereby preventing pressure build-up and the design allows for effective management of annual pressure, which is crucial for the longevity and reliability of the pipeline.
This paper details the design considerations for the Safety liner, highlighting the installation process and best practices for ensuring optimal performance. The system's ability to collect and manage accumulated fluids and gases is a key feature that sets it apart from traditional liners. This includes the installation of external absorption units, which will be connected to vents, which will create a safe passage for the vented gases
The authors explore new generation polymers that may minimize or eliminate the need for venting and annual pressure management. These innovations represent a significant advancement in thermoplastic liner technology, offering enhanced protection against permeation and fluid accumulation.
