Lined Pipe in Alaska

Alaska moves corrosive fluid in some of the harshest conditions on earth, from produced water and methanol on the North Slope to cyanide circuits in the Interior and brine freezers in Dutch Harbor. Marspec Technical Products fabricates steel pipe spools lined with PTFE, PVDF or polypropylene, and supplies lined fittings and valves, for that service, and we ship spools to Alaska the same way we ship to every state, from our shop in Fairhope, Alabama.

A spool that arrives wrong in Deadhorse or Unalaska is expensive to fix, so we build to your isometrics and spark test every liner. Call (251) 625-4949 or contact us online with drawings or a description of the line. We have been fabricating plastic-lined piping for more than fifty years.

Where lined pipe works in Alaska

North Slope oil processing and the pipeline corridor

The Prudhoe Bay and Kuparuk fields anchor North Slope production, and the central processing facilities there separate oil, gas and water before crude enters the trans-Alaska pipeline to Valdez. That means high-chloride produced water and treated seawater for waterflood that corrode carbon steel, plus methanol and glycol for hydrate control and a steady diet of corrosion inhibitor, scale inhibitor and biocide that must reach the injection point clean. PTFE-lined pipe carries all of them, and PVDF all but the amine-based inhibitors, without the internal corrosion that drives so much Slope maintenance, and lined ball and plug valves give chemical injection skids a tight, non-corroding shutoff.

Refining and gas on Cook Inlet and in the Interior

Alaska's refineries are small by Gulf Coast standards but essential: the Nikiski refinery on the Kenai Peninsula, the topping refinery at North Pole outside Fairbanks that makes jet fuel and diesel, and the Valdez refinery beside the pipeline terminal. Nikiski also hosts Cook Inlet gas processing. These plants handle caustic treating, spent caustic, amine, sour water, demineralized water and the hypochlorite and ferric chloride at their wastewater plants. Lined spools and valves let them replace alloy on those lines with carbon steel housings that cost far less.

Gold, zinc and silver mines

Alaska is a major hard-rock mining state. The heap leach and mill at the large gold mine north of Fairbanks, the underground gold mine at Pogo, the silver, zinc and lead mine on Admiralty Island, the gold mine north of Juneau and the Red Dog mine in the Northwest Arctic, one of the largest zinc mines in the world, all run reagent circuits that attack steel. Cyanide leaching uses sodium cyanide at high pH, carbon stripping uses hot caustic and cyanide, carbon acid washing uses hydrochloric or nitric acid, and cyanide destruction uses peroxide or hypochlorite. Mine water treatment adds lime slurry, sulfuric acid and metal-laden water. PTFE-lined pipe handles the acid wash and destruction circuits as well as the caustic and cyanide solution; polypropylene-lined pipe is available for the ambient caustic and cyanide leach lines where a specification calls for it, but not for the hot strip circuit, which runs above its 225 °F (107 °C) limit, and lined sampling valves give assayers a safe draw.

Seafood, water and the coast

Alaska lands more seafood than every other state combined, and the processing plants at Dutch Harbor, the nation's busiest fishing port by volume, along with Kodiak, Bristol Bay, Cordova, Petersburg and Ketchikan run sanitation and freezing chemistry around the clock in season: sodium hypochlorite, chlorine dioxide and peracetic acid sanitizers, hot caustic clean-in-place, and sodium chloride or calcium chloride brine for brine freezing. Brine and hypochlorite together will pit stainless steel; lined pipe and lined diaphragm valves resist both. The water and wastewater utilities in Anchorage, Fairbanks and Juneau dose hypochlorite, ferric chloride and sodium bisulfite through the same kind of lined lines.

Built for Alaska cold

Cold changes the engineering. Liner minimums are -20 °F (-29 °C) for PTFE and 0 °F (-18 °C) for PVDF and polypropylene, and polypropylene can crack if a line is impacted or flexed in the cold. An exposed line in an Interior or North Slope winter gets colder than any of those minimums, so it needs heat tracing and insulation, plus low-temperature (impact-tested) housing steel. Fifty percent caustic freezes at about 54 °F (12 °C) and sets up solid outdoors; methanol injection and glycol lines thicken; brine and hypochlorite feeds stall. Our temperature maintenance products address all of it: electric heat tracing for long runs and remote skids, clamp-on steam heaters where steam is available, and heat-transfer compound to move heat through the steel housing, each sized to keep the liner inside its rating. For jacketed or traced service, we recommend specifying PTFE. We also build spools to exact finished lengths, so the fabricated pipe is ready to bolt up in the cold without the hassle of field fab and liner flaring.

What we ship north

Custom lined pipe spools up to 20 ft long, 1/2" through 12", with PTFE, PVDF or polypropylene liners in carbon steel or 304/316 stainless housings, plus lined pipe and fittings in every common pattern: elbows, tees, crosses, laterals, reducers, flanged spacers and instrument tees. Our lined valves cover ball, plug, butterfly, diaphragm, check and sampling styles, and our accessories include lined strainers, expansion joints, spectacle blinds, sight glasses and solid PTFE pipe. Our lined pipe and fittings comply with ASTM F1545, fittings conform dimensionally to ANSI B16.5 and are welded to ASME B31.3 by welders certified to ASME Section IX, and each lined pipe spool and fitting receives a minimum 10,000-volt spark test. Liner temperature limits, liner thicknesses, flange dimensions and torque tables are on our technical details page.

Serving Anchorage, Fairbanks, the Kenai Peninsula and the Slope

Spools, fittings and valves ship from Fairhope, Alabama, to Anchorage, Fairbanks, North Pole, Kenai, Nikiski, Soldotna, Valdez, Deadhorse and Prudhoe Bay, Juneau, Ketchikan, Kodiak, Unalaska and Dutch Harbor, Naknek, Dillingham and Kotzebue. Tell us the full story: line size, medium, concentration, temperature and the flange standard to match. Call (251) 625-4949 or contact us online and we will quote it.

FAQ: Lined Pipe in Alaska

Which liner should we use for produced water and chemical injection on the North Slope?

PTFE or PVDF. Both resist high-chloride produced water, methanol, glycol and the biocides used on the Slope, and PTFE also takes the amine-based corrosion inhibitors. PTFE is rated to -20 °F (-29 °C) and PVDF to 0 °F (-18 °C), so exposed runs that get colder need electric tracing and insulation, plus low-temperature (impact-tested) housing steel.

Can lined pipe handle cyanide, caustic and acid wash at an Interior Alaska gold mine?

Yes. PTFE-lined pipe and PFA-lined valves handle sodium cyanide and caustic solution, the hydrochloric or nitric acid wash for carbon and the peroxide or hypochlorite used for cyanide destruction on one liner; polypropylene-lined pipe is available for the ambient cyanide and caustic leach lines where your specification names it, but not for the hot strip circuit, which runs above its 225 °F (107 °C) limit. Lined sampling valves add a safe draw point.

Do you supply lined pipe for brine freezing and sanitizer lines at Alaska seafood plants?

We do. Sodium chloride and calcium chloride brine and sodium hypochlorite pit stainless steel over time, and PTFE- or PVDF-lined pipe with lined diaphragm valves, or ball valves with a vented ball (vent facing upstream), eliminates that problem in plants at Dutch Harbor, Kodiak, Bristol Bay and Southeast, with PTFE on full-strength bleach, which carries excess caustic at about pH 12 to 13 that attacks PVDF over time.

How do we keep 50 percent caustic or hypochlorite from freezing at an Alaska plant?

Our temperature maintenance line includes electric heat tracing, clamp-on steam heaters and heat-transfer compound, each sized to the pipe, the medium and the lowest ambient temperature while staying under the liner's limit. For jacketed or traced service, we recommend specifying PTFE. On hypochlorite we trace only to keep it from freezing and never overheat it, since heat speeds its decay. Tell us the conditions and we will size it with the spools.