Gas Permeation in Multi-Layered Composite Pipe for High Pressure Pipelines

Session 5A
11:00

Mel Kanninen, Smart Pipe Company, Inc.

This paper is focused on the use of a pipe that is a composite of thermoplastic materials that has been primarily developed for the internal rehabilitation of damaged/degraded high pressure pipelines. In this technology an arbitrarily high burst pressure is achieved by the use of ultra high strength/light weight ballistic fabrics that are contra helically wrapped onto a polymeric core pipe. Internal rehabilitations are made with pipe manufactured at the job site either by (1) long continuous insertions made possible by folding the composite pipe for ease of insertion, then re-rounding it to become a tight fitting pipe within a pipe, or (2) as a loose fit in relatively short installation lengths where folding is unnecessary; e.g., in cased crossings. In either mode there is no theoretical limit on the operating pressure; an embedded fiber optic sensor system detects and precisely locates mechanical impacts, leaks, and ground movements; and installation in buried pipelines can be accomplished with minimal surface disruption.

Among many other challenges in the engineering of a thermoplastic composite pipe for high pressure service, because the gas permeation rate in thermoplastic materials is directly proportional to pressure, this phenomenon must be quantified. For this objective, a soundly based permeation predictive model based on classical diffusion theory buttressed by testing work has been developed. This methodology applies to the full range of permeation in reinforced plastic pipe carrying methane, hydrogen, CO2, and other greenhouse gases for which diffusion/permeation data are available. It uniquely includes the effects of an internal pressure build-up in the reinforcement layer of the composite, as well as for the back pressure from permeation that builds-up in the annulus between a rigid steel host pipe and a flexible inner reinforcement pipe. While the progress presented in this paper is specifically focused on the internal rehabilitation of damaged/degraded steel pipe by multi-layered thermoplastic composite pipes, it may also be useful for non reinforced plastic pipe as well as for all other types of multi-layered composite pipe.

Mel Kanninen
Senior Technical Adviser

Kyle Bethel
Chief Operating Officer

Aron Ekelund
Factory Operations Manager

Smart Pipe Company, Inc.