A thermoplastic resin piping system connecting landfill gas to the local gas distribution system will save operators money with reduced installation cost and minimal maintenance cost compared to steel, says chemicals producer Arkema, which manufactured the plastic piping.
Arkema, Georg Fischer Central Plastics, and BioResource Development (BRD) teamed up to install the polyamide 11 (PA11) piping system near Omaha, Nebraska. The project demonstrates the advances made in thermoplastic piping systems and the cost savings operators can realize from choosing high-pressure, PA11 plastic piping, the companies say.
Polyamide 11 is marketed under the Rilsan trade name. Arkema designed this specific Rilsan PA11 grade exclusively for onshore oil and gas piping applications. The PA11 is derived from a bio-renewable source, castor oil.
Georg Fischer supplies the piping, fittings and transitions, offering a complete PA11 piping system under the Hyperplast trade name. BRD based in Nebraska, develops, manages and operates the collection, treatment, production, storage, and distribution of biofuels made from renewable sources, such as landfills, feedlots, and domestic wastewater plants.
For this project, BRD needed a 3-mile piping system that could be operated at up to 200 psi to transport the methane produced by the State Street Landfill, operated by Douglas County, in Nebraska. The pressure requirements exceeded the tolerances that HDPE offers, resulting in BRD’s move to consider either PA11 or steel.
The upfront economics for PA11 were far more attractive than steel, says Greg Maclean, co-founder of BRD.
Rilsan PA11 offers higher pressure and temperature capabilities compared to HDPE due to its chemical structure. It was approved by the Pipeline and Hazardous Materials Safety Administration (PHMSA) for use in regulated gas pipelines in December 2008.
PHMSA permits the use of PA11 pipe for up to 4-inch diameter piping and 200 psi, although the material can achieve 6-inch, 250 psi with a special waiver. The material also can be used for oilfield applications, including oil/gas gathering and water flow lines at pressures exceeding 300 psi.
The value in Rilsan PA11 is embedded in the reduced installation cost and minimal maintenance cost compared to steel. Arkema and BRD estimate a CAPEX savings of $95,000/mile, and significant additional savings from the minimum maintenance when compared to epoxy coated steel pipe. From historical data on previous installations, Arkema estimates maintenance savings of $6,300/mile each year when choosing PA11 over steel.
Arkema also estimates there is a significant economic advantage of PA11 over steel for pipe sizes up to and including 6 inches in diameter.
BRD is anticipating production of approximately 130,000-140,000 MMBTU/yr of untreated gas from the State Street landfill. The landfill received its last solid waste in 1989 and began collecting and flaring the landfill gas in 1995. The 2-inch line will tie into Metropolitan Utilities District’s 12-inch, 125 psi gas main in Omaha that feeds their liquefaction facility. The pipeline is privately owned and operated by BRD.
USDI Engineering was the design engineer and construction observer, and Michels Corporation constructed the system. The 3-mile-long project was installed in just over four working weeks, beginning in December and ending in January 2015.